Lower Extremity Flashcards
Which of the following conditions is a relative CONTRAINDICATION for use of the flap in the image shown for reconstruction of an 8 x 10-cm anterior ankle wound?
A) Diabetes mellitus
B) Hypertension
C) Joint exposure with loss of the joint capsule
D) Occlusion of the peroneal artery
E) Underlying osteomyelitis
The correct response is Option D.
Hypertension does not preclude the use of any fasciocutaneous flaps in the lower extremity.
Diabetes mellitus can be associated with peripheral vascular disease, but by itself, would not prevent successful use of the reverse sural artery flap for foot or ankle reconstruction. Appropriate preoperative workup would include noninvasive ultrasound study of the lower extremity vasculature to prove the peroneal artery was patent.
Vascularized flaps, including the reverse sural artery flap, provide excellent coverage for foot/ankle wounds, including those with underlying osteomyelitis. Effective treatment would necessitate adequate debridement and antibiotic therapy as part of the reconstructive paradigm.
The distally based sural artery flap receives its blood supply from a few sources, the most robust of which are perforators from the peroneal artery. The most distal of these perforators arise between 4 and 7 cm proximal to the lateral malleolus. Additional perfusion arises from neurocutaneous perforators from the sural nerve and venocutaneous perforators from the lesser saphenous vein.
2018
A 61-year-old man comes to the office for evaluation of a 3 x 3-cm calcaneal defect with exposed bone. Medial plantar flap reconstruction is planned. The principal blood supply to this flap arises from which of the following arteries?
A) Arcuate
B) Dorsalis pedis
C) Peroneal
D) Plantar arch
E) Posterior tibial
The correct response is Option E.
The primary blood supply to the medial plantar flap is the medial plantar artery, a terminal branch of the posterior tibial artery. The dorsalis pedis is the continuation of the anterior tibial artery and does not contribute to this flap. The peroneal artery is a proximal branch of the posterior tibial artery and descends in the deep posterior compartment posterior to the tibialis posterior and anterior to the flexor hallucis longus; it does not contribute to this flap. The arcuate artery is the terminal branch of the anterior tibial artery. The plantar arch runs on the plantar aspect of the foot at the level of the metatarsals; it is formed from a confluence of the lateral plantar artery and the deep plantar artery from the dorsalis pedis.
2018
A 60-year-old man sustains a Gustilo type IIIB open fracture of the distal left tibia during a boating accident. There is severe contamination of the wound, and the patient undergoes multiple formal washouts in the operating room. There is no neurovascular compromise of the extremity. He undergoes external fixation to stabilize the limb. Which of the following is the most appropriate next step in treatment?
A) Coverage with a free tissue transfer
B) Negative pressure wound therapy until secondary healing is achieved
C) Pedicled gastrocnemius muscle and skin grafting
D) Primary bone allografting
E) Split-thickness skin grafting
The correct response is Option A.
The Gustilo classification describes open fractures of the tibia by the severity of the soft tissue injury overlying the fracture. In patients with IIIB injuries, there is extensive soft-tissue loss and periosteal stripping, but no vascular compromise requiring repair.
Gustilo classification:
Type I: The wound is less than 1 cm long. There is little soft-tissue damage and no sign of crush injury. There is no or minimal comminution of the fracture.
Type II: The laceration is more than 1 cm long but there is no extensive soft tissue damage, flap, or avulsion. There is slight to moderate crushing injury, moderate comminution of the fracture.
Type III: Extensive damage to the soft tissues, including muscle, skin, and neurovascular structures, and a high degree of contamination.
Type IIIA: Soft tissue coverage of the bone is adequate.
Type IIIB: Extensive injury to or loss of soft tissue, with periosteal stripping and exposure of bone, massive contamination, and severe comminution of the fracture from high-velocity trauma
Type IIIC: Any open fracture with a vascular injury requiring repair.
Free tissue transfer will bring healthy, nontraumatized tissue into the area to cover the exposed broken bone. Multiple recent studies have shown equivalence of muscle versus skin/fat/fascia flaps for coverage of the open fracture even in patients with osteomyelitis. Negative pressure wound therapy has proven to be an excellent adjunct in the management of patients with these injuries. Between washouts, negative pressure devices can help decrease edema and isolate the wound and bone from the outside world. In a patient with a IIIB injury, there is insufficient tissue available to cover the wound. Therefore, secondary intention would not close the wound.
Split-thickness skin grafting provides an epithelial barrier to help seal off a wound from outside contamination. Grafts require a viable wound bed to survive. There must be a pliable bed to help grafts resist minor trauma in the future. With the periosteal stripping in this type of injury, a graft would not survive. In addition, graft placed directly on bone with periosteum would be very vulnerable to breakdown from minor trauma.
Bone allografting can be used to bridge defects in many circumstances. In the patient described, the severe contamination of the initial injury would make bone allografting much less appealing than autografting. Because of contamination, any type of bone grafting may need to be delayed until after achieving stable soft tissue coverage of the fracture.
A pedicled gastrocnemius muscle flap provides excellent coverage for defects about the knee, including the proximal tibia. Although the free gastrocnemius muscle flap could be transferred to any location, the pedicled flap would not be able to reach the distal tibia.
2018
A 50-year-old man comes for evaluation 8 weeks after dislocating the right knee when he tripped on a railroad tie at work. Physical examination shows a right footdrop and dysesthesia along the lateral lower leg and dorsolateral foot. Electromyography and nerve conduction studies are most likely to confirm injury to which of the following nerves?
A) Femoral
B) Peroneal
C) Plantar
D) Sural
E) Tibial
The correct response is Option B.
The peroneal nerve innervates the tibialis anterior and extrinsic extensors of the toes, thereby extending the ankle. Paralysis of these muscles leads to footdrop. The sural nerve is a cutaneous nerve about the lateral ankle. The tibial nerve innervates the ankle and toe flexors, and paralysis of this nerve would not lead to a footdrop. The femoral nerve runs in the anterior thigh and is not likely to be affected by a knee dislocation; it innervates the extensors of the leg at the knee. The plantar nerves are the terminal branches of the tibial nerve and provide intrinsic innervation to the foot and sensation to the medial and lateral plantar foot.
2018
A 40-year-old man sustains an avulsion of the weight-bearing portion of the medial heel. Coverage with an instep flap is planned. Sensation to this flap is provided by which of the following?
A) Lateral plantar nerve from the deep peroneal nerve
B) Lateral plantar nerve from the superficial peroneal nerve
C) Lateral plantar nerve from the sural nerve
D) Medial plantar nerve from the deep peroneal nerve
E) Medial plantar nerve from the tibial nerve
The correct response is Option E.
The medial plantar artery flap, or instep flap, provides sensate, full-thickness glabrous skin and subcutaneous tissue that can be transferred as a pedicled or free flap. The tissue is well suited for weight-bearing areas of the foot but has also been used as a free tissue transfer for palmar defects. Because the instep donor site is non–weight-bearing, the donor site can be covered with a skin graft. The innervation of the medial instep flap comes from the medial plantar nerve, a branch of the tibial nerve.
2018
A 65-year-old man is referred for evaluation of a 3 x 4-cm wound with exposed tendon over the distal anterior tibia after sustaining fracture to the lateral malleolus, which was successfully treated with cast immobilization. The wound had been managed with local wound care for the past several weeks. Physical examination shows a clean wound with some fibrinous exudate. Periosteum and peritenon are intact. Pulses cannot be palpated. Pencil Doppler signals in dorsalis pedis and posterior tibialis are noted. Which of the following studies is the most appropriate next step in management?
A) Ankle brachial index
B) CT angiography
C) MRA
D) MRI
E) Percutaneous angiography
The correct response is Option A.
This patient has a pressure sore from cast immobilization. He also has asymptomatic peripheral vascular disease, as is evidenced from his clinical examination. For the lower extremity to heal, adequate blood flow is required and this can be most effectively quantified with an ankle brachial index measurement. Ankle brachial index less than or equal to 0.9 establishes the presence of peripheral artery disease. Ankle brachial index between 0.5 and 0.79 yields wound healing issues and less than 0.5 results in rest pain and arterial insufficiency.
CT angiography, MRI, MRA, and percutaneous angiography can assist in delineating anatomy but they do not yield clinically helpful information about perfusion, prognosis, or stratification of peripheral artery disease.
2018
A 50-year-old man comes to the office because of a persistent nonhealing wound 6 months after he underwent open reduction and internal fixation of an open ankle fracture. Examination shows palpable pedal pulse with retained protective sensation of the foot. Which of the following is the most appropriate initial step in management of this patient?
A) Application of collagenase ointment
B) Core needle bone culture
C) Coverage with a free flap
D) Operative debridement
E) Referral for hyperbaric oxygen therapy
The correct response is Option D.
The patient is at high risk for fracture nonunion and osteomyelitis. The best next course of management is operative debridement ideally along with the treating orthopedist to make judgments about bone viability and debridement and the risks and benefits of hardware removal. Enzymatic wound debridement would not address the concerns about the deeper wound issues. The role for hyperbaric oxygen in the scenario presented is not well established. Bone cultures at the time of operative debridement should be obtained; but, percutaneous core needle cultures alone would not likely be adequate to obtain best healing. Free flap coverage may be required but is not indicated at this time.
2018
A 50-year-old woman with systemic lupus erythematosus is evaluated because of a nonhealing ulcer of the right lower extremity. It started as a small pustule 3 months ago and steadily worsened to an ulcerative lesion. Examination of a biopsy specimen ruled out malignancy. Cultures have been negative for more than 4 weeks. Debridement of the wound and skin grafting are attempted but result in loss of the graft and development of similar ulcerative areas at the donor site. Which of the following is the most appropriate next step in management?
A) Bilayer skin substitute
B) Fasciocutaneous flap
C) Hyperbaric oxygen therapy
D) Long-term antibiotic therapy
E) Systemic corticosteroid therapy
The correct response is Option E.
The most appropriate next therapy option for this patient is systemic corticosteroids. These ulcerative lesions are most likely pyoderma gangrenosum (PG), an ulcerative cutaneous condition of unknown etiology. This condition is most likely associated with other systemic diseases like inflammatory bowel disease, or immunologic diseases. This diagnosis is usually one of exclusion, and one must have a high index of suspicion for ulcerative wounds that are persistent despite adequate workup and treatment. One must be especially aware of PG’s association with a condition known as pathergy. This is a phenomenon in which surgical manipulation of the area or distant sites may trigger worsening of the ulcerative condition and/or development of the condition in an area of skin trauma. First-line therapy for PG involves the use of prednisone. Other anti-inflammatory agents, including immunosuppressive agents, and biologic agents have also been used. The prognosis is generally good; however, the disease can recur and residual scarring is common. Because of these factors, the other options are not the most appropriate next steps in the treatment of this patient.
2017
A 55-year-old man comes to the office because of an exposed knee prosthesis. Repair with a gastrocnemius flap is planned, using the entire muscle for reconstruction of the anterior knee defect and hardware coverage. The biomechanical consequence of using this flap is most likely to be observed by which of the following motions?
A) Dorsiflexion
B) Foot eversion
C) Foot inversion
D) Leg extension
E) Plantar flexion
The correct response is Option E.
The most appropriate answer is plantar flexion. The gastrocnemius muscle originates as two heads off the femur. The medial head comes off the medial condyle of the femur, just above the condyle and the lateral head comes off just above the lateral condyle. The muscle inserts onto the posterior calcaneus via the calcaneal tendon. This is the common tendon shared with the soleus muscle. Because of this fact, both heads can be harvested and the patient still maintains 75% of plantar flexion strength. The function of the gastrocnemius muscle is to plantar flex the foot and also flex the leg at the knee. Plantar flexion is the only biomechanical consequence listed above, although minimal. The blood supplies to the gastrocnemius muscle are from the sural branches of the popliteal artery and are independent. The medial head is the larger of the two and will have a larger arc of rotation. The innervation is via separate branches to each head off the tibial nerve.
2017
A 68-year-old man presents 3 months after undergoing reconstruction of a large mandibular defect following tumor resection with a right fibula osteocutaneous flap. Postoperatively, immediate footdrop is noted. Which of the following is the most appropriate next step in management?
A) Clinical observation, conservative management, and re-evaluation in 3 months
B) Exploration of the peroneal nerve, neurolysis, and primary repair if transected
C) Exploration of the sural nerve, neurolysis, and primary repair if transected
D) Exploration of the tibial nerve, neurolysis, and primary repair if transected
The correct response is Option B.
It is recommended that the proximal 4 to 8 cm of the fibula be preserved in order to prevent knee instability and to avoid injury to the peroneal nerve. In large resections, more fibula length is required and the fibular head is often useful in the reconstruction. The common peroneal nerve is formed by the lateral division of the sciatic nerve. The peroneal nerve wraps around the lateral surface of the biceps femoris tendon and fibular head and courses into the anterolateral portion of the leg. The common peroneal nerve trifurcates into the superficial peroneal nerve, the deep peroneal nerve, and the recurrent articular branch. The deep peroneal nerve innervates the anterior compartment muscles of the leg, and provides ankle dorsiflexion. Injury to the common or deep peroneal nerve can result in footdrop or weakened dorsiflexion. Given that this patient had a large resection, the footdrop is indicative of a peroneal nerve injury. Exploration is warranted. The tibial nerve is a branch of the sciatic nerve and runs in the popliteal fossa to pass below the arch of the soleus muscle. The sural nerve is a sensory nerve in the calf. Injury to the tibial or sural nerve would not cause a footdrop.
2017
A 40-year-old man is brought to the emergency department because of a grade IIIB open fracture of the right distal aspect of the tibia and fibula sustained during a motorcycle collision. The plastic surgeon is consulted after initial debridement and external fixation of the fracture. Examination shows a 10-cm open wound of the right medial ankle with complete transection of the tibial nerve. The tibia fracture is comminuted but without marked bone loss. The foot is well perfused, but single-vessel run-off through the anterior tibial artery is noted. Which of the following is the most appropriate management of this patient’s condition?
A) Debridement and free muscle flap without nerve repair
B) Debridement, tibial nerve repair, and coverage with a bilaminar acellular dermal regeneration template
C) Debridement, tibial nerve repair, and coverage with a free fasciocutaneous flap
D) Debridement, tibial nerve repair, and coverage with a pedicled reverse sural fasciocutaneous flap
E) Primary below-knee amputation
The correct response is Option C.
The answer is debridement with repair of the tibial nerve and coverage with an anterolateral thigh (ALT) free flap. This patient is presenting with a grade IIIB open fracture of the distal tibia and fibula with an open medial wound. Traditionally, lower extremity injuries with an insensate plantar foot were considered unsalvageable. However, more recent data have demonstrated that an insensate foot by itself should not be considered a contraindication to limb salvage if repair is otherwise possible. Studies have shown equivalent long-term outcomes with limb salvage and primary amputation and that half of the patients with tibial nerve injuries will regain plantar sensation within two years post-injury. This vignette describes a situation in which one could reasonably expect a successful outcome.
The size and location of the wound are most amenable to coverage with a microvascular free flap. In this instance, a fasciocutaneous flap will provide adequate soft-tissue coverage with minimal donor morbidity and potentially better long-term outcome if secondary bone grafting or hardware revision is required.
The reverse sural fasciocutaneous is a versatile flap that can be used for reconstruction of many different wounds of the distal lower extremity. The flap is a neurocutaneous flap supplied by the vascular axis of the sural nerve as well as distal peroneal artery perforators. In this case, the peroneal artery was damaged from the trauma and the pedicle of the flap is in the zone of injury, making it an inappropriate choice for reconstruction when better options are available.
The use of biologic materials such as bilaminar acellular dermal regeneration templates have been used successfully to cover wounds with exposed vital structures such as bone, tendon, and nerve. However, its use is best suited for smaller wounds or in patients in whom microvascular reconstruction is contraindicated or not desired. This patient required soft-tissue coverage over a major nerve repair and a comminuted fracture with internal hardware. A microvascular free flap would be the method of choice in this patient when feasible.
As stated previously, up to fifty percent of patients with tibial nerve injuries will recover plantar sensation after nerve repair. Nerve repair should be attempted to improve the overall outcome.
2017
A 49-year-old man comes to the office because of dull, aching pain over the dorsum of the foot. Nerve study shows no abnormalities of the nerves around the knee but chronic denervation in the extensor digitorum brevis at the dorsum of the foot. Which of the following nerves is most likely to be entrapped?
A) Anterior tibial
B) Deep peroneal
C) Lesser saphenous
D) Medial plantar
E) Medial sural
The correct response is Option B.
The deep peroneal nerve emerges from the leg anterior compartment musculature, from beneath the extensor retinaculum of the ankle. The nerve gives off a motor branch to the extensor digitorum brevis, and then terminates into the first web space of the foot, after running beneath the tendon of the extensor hallucis brevis. Entrapment of this nerve, as it exits the extensor retinaculum of the ankle, can manifest itself as pain, weakness, or numbness or tingling over the dorsum of the foot. The saphenous nerve innervates the cutaneous region over the anterior-medial aspect of the distal leg and ankle. The medial sural nerve innervates the cutaneous region over the posterior lateral aspect of the lower leg. The tibial nerve innervates the plantar surface of the foot. It divides into the medial and lateral plantar nerve over the plantar aspect of the foot. The medial and lateral plantar nerves innervate the cutaneous aspect of the plantar foot and the intrinsic musculature of the foot.
2017
A 62-year-old man comes to the office because of an open ankle fracture with exposed hardware. Use of a sural artery flap for reconstruction is planned. Which of the following veins must be harvested within the flap?
A) Anterior tibial
B) Lesser saphenous
C) Peroneal
D) Popliteal
E) Posterior tibial
The correct response is Option B.
The sural artery flap is a cutaneous flap located on the posterior aspect of the lower leg. The flap is based on the arteries that accompany the lesser saphenous vein and sural nerve; the vein and nerve must be included in the flap. The axial pattern flap can cover defects around the knee and upper third of the leg. The reverse flow flap was first introduced by Masquelet in 1992 and is a workhorse flap for pedicle reconstruction of the lower third defects in the leg. The anterior tibial, posterior tibial, popliteal, and peroneal veins do not contribute to the vascular anatomy of this flap.
2017
A 26-year-old man comes to the office for evaluation after sustaining an open injury to the right knee during a motorcycle collision 2 weeks ago. Physical examination shows a 2-cm defect over the patella. A medial gastrocnemius flap is planned to close the defect. Which of the following is the dominant vascular supply to this muscle?
A) Anterior tibial
B) Inferior geniculate
C) Medial sural
D) Posterior tibial
E) Superior geniculate
The correct response is Option C.
The gastrocnemius flap is the primary flap used to cover soft-tissue defects of the upper third of the tibia and knee. The gastrocnemius muscle is a bipennate muscle located on the posterior surface of the lower leg. The muscle originates from the medial and lateral condyles of the femur and inserts into the Achilles tendon. The dominant blood supply of the muscle is the medial and lateral sural arteries, which are branches of the popliteal artery. Generally only one head of the gastrocnemius flap is harvested to cover soft-tissue defects. The muscle alone is generally taken and is covered with a split-thickness skin graft for lower extremity reconstructions. The geniculate arteries primarily supply the bone around the knee joint.
2017
A 30-year-old man is evaluated after sustaining multiple gunshot wounds to the right leg and thigh. X-ray study shows no retained foreign bodies and no fractures. On physical examination, the patient’s foot is warm, with palpable pulses at the ankle. He is able to extend the toes, dorsiflex the ankle, and evert the ankle. He is unable to flex his toes. He has normal sensation to the dorsum of his foot and medial-most part of the instep and lateral-most midfoot/hindfoot. Which of the following nerves is most likely injured in this patient?
A) Common peroneal nerve
B) Femoral nerve
C) Saphenous nerve
D) Sural nerve
E) Tibial nerve
The correct response is Option E.
Gunshot wounds can create a range of nerve injuries from contusion to transection. Electrodiagnostic testing can be very helpful in later diagnosis and intraoperatively during nerve reconstruction but will not demonstrate changes in the nerve on the day of injury. EMG/nerve conduction testing will not demonstrate changes in findings until 2 to 6 weeks after injury. An accurate sensory and motor examination is the best initial step to identify abnormalities that can be tracked over time.
The common peroneal nerve provides motor axons to the anterior and lateral compartment muscles. It also provides sensory axons to the dorsal foot, primarily via the terminal branches of the superficial peroneal nerve. Its only branch above the knee is to the lateral knee joint capsule.
The saphenous nerve receives the terminal branches of the femoral nerve. It provides sensation to the medial-most plantar surface of the instep.
The femoral nerve provides sensation to the thigh via cutaneous nerve branches as well as motor axons to the quadriceps muscle. Its terminal sensory fibers reach the foot via the saphenous nerve.
The sural nerve is a terminal branch of the tibial nerve. It provides motor axons to the gastrocnemius muscle and sensory fibers to the lateral-most forefoot and midfoot dorsally and lateral-most midfoot and hindfoot plantarly.
The tibial nerve provides sensation to the majority of the plantar surface of the foot via the medial and lateral plantar nerves. It also provides motor axons to the muscles of the deep posterior compartment, including the toe flexors. For the patient in this scenario, the tibial nerve is injured distal to the takeoff of the sural nerve.
2017
A 30-year-old man comes to the office because of stage IV heel pressure ulcer of the right foot. Reconstruction with a medial plantar artery flap is performed. The pedicle for this flap derives from which of the following arteries in the lower extremity?
A) Anterior tibial
B) Dorsalis pedis
C) Lateral plantar
D) Peroneal
E) Posterior tibial
The correct response is Option E.
The medial instep flap (or medial plantar artery flap) is an ideal choice for coverage of a heel defect in a patient with adequate peripheral vasculature. This flap is based on the medial plantar branch of the posterior tibial artery. This vessel lies between the abductor hallucis and flexor digitorum brevis muscles.
The lateral plantar artery supplies the lateral aspect of the sole and digits but does not supply the medial instep. The anterior tibial artery and dorsalis pedis supply the dorsum of the foot and digits and are not involved in this flap. The peroneal artery is used in a fibular flap but not in the foot.
2017
A 60-year-old man with type 2 diabetes mellitus comes to the office because of a diabetic ulcer on the sole of the right foot. Treatment of the ulcer with a medial plantar artery flap is planned. Against which of the following muscles is the arterial perforator located?
A) Adductor hallucis
B) Flexor hallucis
C) Lumbrical
D) Plantar interosseous
E) Quadratus plantae
The correct response is Option B.
The medial plantar artery flap is elevated starting at the plantar aspect, deep to the muscular fascia. The perforator is identified between the flexor hallucis and abductor hallucis muscles. The perforator is then dissected toward its origin on the medial plantar artery in the intermuscular space.
2017
A 19-year-old man is brought to the emergency department after being thrown from his motorcycle. The trauma team has ruled out intracranial, thoracic, abdominal, and spinal injury. A comminuted tibia fracture is visible through a 7-cm full-thickness soft-tissue avulsion of the lower one third of the leg. Which of the following is the most appropriate next step in management?
A) Intraoperative debridement and washout of the wound, external fixation, and immediate cross-leg flap
B) Intraoperative debridement and washout of the wound, external fixation, burring of the tibia, and formation of granulation tissue over the next several weeks
C) Intraoperative debridement and washout of the wound, placement of external fixator, serial debridement, and free tissue transfer within 1 week of injury
D) Irrigation of the wound, stabilization of reduction with a cast, and application of suction wound dressing
E) Serial debridement of the wound and coverage with a gastrocnemius muscle flap
The correct response is Option C.
Lower extremity open fractures are described using the Gustilo classification. The patient in this scenario has a Gustilo IIIB: extensive soft tissue avulsion or degloving, from high velocity injury and gross contamination. The best treatment for such injuries is intraoperative debridement and washout with early or immediate fracture stabilization, often with an external fixator. Immediate soft-tissue reconstruction is not done due to the high-energy mechanism and gross contamination. This mandates repeat evaluation to assure all nonviable tissue and foreign material are removed prior to reconstruction. Definitive and stable soft-tissue reconstruction should be done as soon as possible and is classically thought to be best when provided within 72 hours of injury. Soft-tissue reconstruction done as quickly as possible reduces the risk of nonunion and osteomyelitis. In the proximal third of the leg, the gastrocnemius flap is indicated, while the soleus flap is for the middle third. Most often, free tissue transfer is the best option for the distal third wounds. Cross-leg flap is seldom used because of the prolonged immobilization that is required. Delayed reconstruction beyond the one week window is sometimes necessary because of other confounding factors in a multiple-trauma patient. In such situations, preventing desiccation of the bone is necessary, for which negative pressure wound therapy is useful. Soft tissue reconstruction is then accomplished when feasible with preference for flap reconstruction.
2017
A 65-year-old man comes to the office because of an infected wound to the left plantar region. Medical history includes type 2 diabetes mellitus. Dorsalis pedis and posterior tibial pulses are not palpable but are located with a handheld Doppler probe. Ankle brachial index cannot be obtained because of noncompressible vessels in the left lower extremity, below the knee. Which of the following is the most appropriate next step in evaluating the arterial perfusion of this patient’s foot?
A) Computed tomography arteriography
B) Magnetic resonance arteriography
C) Percutaneous arteriography
D) Repeat ankle brachial index
E) Toe brachial index
The correct response is Option E.
The most appropriate next step when evaluating the arterial perfusion of this diabetic patient’s foot is obtaining a toe-brachial index (TBI). TBI is calculated by dividing the great toe systolic pressure by the brachial systolic pressure. An index of >0.7 is considered normal.
Patients with diabetes mellitus have a higher incidence of peripheral arterial disease than the non-diabetic population. Atherosclerotic lesions in diabetic patients tend to favor the arteries below the knee, which also commonly display medial calcinosis, causing stiffening of the arterial walls, poor compressibility, and an unreliably high ankle-brachial index (ABI). Interestingly, the small vessels of the great toes are usually spared of disease, therefore the diagnostic advantage of TBIs. These features should be taken into consideration whenever assessing arterial blood flow to the distal lower extremity of a diabetic patient.
Percutaneous arteriography is an invasive procedure and should be reserved for when surgical or endovascular therapeutic interventions are anticipated. Computed tomography arteriography and magnetic resonance arteriography may also be used in the diagnosis of peripheral artery disease in the lower extremities, but a normal TBI would most likely preclude their need. Repeating the ABI would most likely render a similar result, as the inability to compress the arteries in the leg is due to stiffened vessel walls.
2017
A functional 56-year-old woman who has a 20-year history of diabetes mellitus is referred for evaluation of a chronic calcaneal ulcer. The wound has failed to heal with bedside debridement, local wound care, and pressure offloading. On examination, the wound measures 6 × 8 cm with exposed bone and presumed osteomyelitis. CT angiography shows single-vessel flow to the foot through the posterior tibial artery. Clinically, the patient’s foot is warm to the touch with capillary refill time of 2 seconds. Which of the following is the most effective management?
A) Below-knee amputation
B) Hyperbaric oxygen therapy
C) Microsurgical free flap reconstruction
D) Operative debridement and placement of a collagen bilayer wound matrix dressing
E) Repeat bedside debridement and negative pressure therapy
The correct response is Option C.
The optimal choice in this patient is free flap reconstruction.
When possible, limb salvage is the ultimate treatment goal for patients with diabetic ulcers. As many as 25% of diabetic patients will develop lower extremity ulcers. In addition to significant physical, psychological, and economic impact, patients with diabetic ulcers have an eightfold increased chance of lower extremity amputation. Furthermore, studies show the 5-year mortality rate following lower extremity amputation ranges from 39 to 80%.
This patient has a nonhealing diabetic foot ulcer that has failed adequate nonoperative treatment. Treatment of diabetic ulcers is multifactorial and should include optimizing glucose control and other associated medical comorbidities. If the progress of the wound has stalled despite adequate infection control, edema control, vascular inflow, and pressure offloading, the patient is a candidate for soft-tissue reconstruction. Studies show greater than 90% flap survival with microsurgical reconstruction and limb salvage greater than 80%. Microsurgical free flaps allow the transfer of well-vascularized tissue to provide wound coverage and adequate soft tissue thickness to cover a weight-bearing surface of the foot.
This patient has not had success with bedside debridement and local wound care. Negative pressure dressings often are used as advanced wound care but are not appropriate when underlying infection or necrotic tissue is present. Bedside debridements are not adequate to treat osteomyelitis.
Hyperbaric oxygen therapy can be used as an adjunct to local wound care or following flap surgery to optimize perfusion and wound healing. However, hyperbaric oxygen therapy is not the most effective treatment for a wound this large in a patient who is able to undergo surgery.
The goal of treatment in diabetic ulcers should be limb salvage. The indications for amputation in diabetic foot ulcers include systemic sepsis, major tissue loss, multiple comorbid conditions, patient noncompliance, and nonreconstructable vascular disease. These are not present in this patient.
Collagen bilayer matrix allows for the formation of a neodermis and is a useful adjunct for the management of chronic wounds or wounds with exposed vital structures when autologous tissue is unavailable or inappropriate. The collagen matrix provides a scaffold for cellular ingrowth and angiogenesis. In this case, a bilayer wound matrix may allow for wound closure but would be inferior to a free flap for durability and improving foot vascularity.
2016
A 25-year-old surfer who sustained a shark bite to the left thigh is brought to the emergency department. The patient is hemodynamically stable. Physical examination shows a bleeding mid-thigh wound. The left foot is pale and cool; sensibility in the foot is decreased. The ankle pulses are absent. On surgical exploration, a 6-cm injury to the superficial femoral artery is identified. After local debridement, which of the following is the most appropriate next step in management of the artery?
A) End-to-end anastomosis
B) End-to-side anastomosis
C) Interposition prosthetic grafting
D) Interposition vein grafting
The correct response is Option D.
The patient has a major vascular injury that is greater than 5.5 cm in length. A shark bite is considered contaminated and requires debridement. Because of the length of arterial injury, vein grafting is the most appropriate management option. End-to-end and end-to-side anastomoses are incorrect because the arterial defect is too long. The use of prosthetic material is incorrect because this is a contaminated wound, increasing the risk for infection.
2016
Which of the following compartment pressure measurements is the minimum threshold that is most consistent with compartment syndrome?
A) 10 mmHg
B) 20 mmHg
C) 30 mmHg
D) 40 mmHg
E) 50 mmHg
The correct response is Option C.
The absolute minimum compartment pressure measurements ranging from 25 to 50 mmHg are quoted as absolute indications for fasciotomy. The most frequently quoted absolute measurement is 30 mmHg.
2016
A 28-year-old man is flown by helicopter to the emergency department after sustaining a deep, isolated, lateral abrasion to the right lower leg in a motorcycle collision. On physical examination, he has a segmental injury to the common peroneal nerve. Repair with a sural nerve autograft is planned. Which of the following is the maximum length at which any functional recovery is expected?
A) 3 cm
B) 6 cm
C) 9 cm
D) 12 cm
E) 15 cm
The correct response is Option D.
Nerve repair outcomes are related to mechanism of injury, need for a graft and graft length, and timing of surgery relative to injury. Although results vary, good results are typical for grafts measuring less than 6 cm, and may be possible in approximately 25% of patients with grafts measuring 6 to 12 cm. Almost no studies report an M4 motor recovery or better when a graft greater than 12 cm is used.
2016
A 35-year-old man who was involved in a motorcycle accident sustains fractures to the right tibia and fibula. On physical examination, he has numbness in the dorsum of the right foot and inability to dorsiflex the foot. Vascular status of the right lower extremity is normal. Which of the following nerves has most likely been injured?
A) Calcaneal
B) Common peroneal
C) Lateral plantar
D) Lateral sural cutaneous
E) Posterior tibial
The correct response is Option B.
The common peroneal nerve derives from the dorsal branches of the fourth and fifth lumbar and first and second sacral nerves. The common peroneal nerve lies between the biceps femoris and lateral head of the gastrocnemius muscle; it continues around the neck of the fibula between the peroneus longus muscle and the fibula, and then branches into the superficial fibular and deep fibular nerves. The common peroneal nerve innervates the peroneus longus, peroneus brevis, and biceps femoris muscle. Injury to this nerve results in a foot drop and sensory loss to the dorsal surface of the foot.
The lateral sural nerve is a cutaneous nerve arising from the common fibular nerve. It supplies sensation to the posterior and lateral surfaces of the leg. This nerve does not supply motor innervation.
The posterior tibial nerve, also known as the tibial nerve, is derived from L4, L5, S1, S2, and S3. It is a branch of the sciatic nerve. The nerve gives branches to the gastrocnemius, popliteus, and soleus muscles. Below the soleus muscle it supplies the tibialis posterior, the flexor digitorum longus, and the flexor hallucis longus muscles.
The lateral plantar nerve is a branch of the tibial nerve. It supplies the quadratus plantae and the abductor digiti minimi muscles. Its sensory component supplies the skin of the fifth toe and the lateral half of the fourth toe.
The lateral calcaneal nerve is a branch of the sural nerve supplying cutaneous sensation to the lateral aspect of the heel skin. This nerve is a cutaneous nerve with no muscle innervation.
2016
A 35-year-old man is brought to the emergency department because of an injury to the left lower leg after being involved in a motorcycle collision. X-ray studies confirm a Gustilo IIIB tibia-fibula fracture. After debridement, there is a bone defect measuring 12 cm in the mid shaft of the tibia. Which of the following is the most appropriate technique to restore the bone defect?
A) Autogenous bone grafting
B) Cadaveric bone grafting
C) Coverage with a fibular free flap
D) Osteodistraction
The correct response is Option C.
Although various techniques have been used successfully to reconstruct large bony defects of the lower extremity, the most reliable technique for such a large bone gap is the fibular free flap reconstruction. The Ilizarov osteodistraction technique can be used for large defects, but would necessitate a very long period of immobilization and fixation. Neither autogenous nor cadaveric bone graft would be as reliable as vascularized bone.
2016
A 27-year-old man is brought to the emergency department because of compartment syndrome of the lower left leg. Release of the deep posterior compartment includes decompression of which of the following muscles?
A) Flexor hallucis longus
B) Peroneus brevis
C) Plantaris
D) Soleus
E) Tibialis anterior
The correct response is Option A.
The flexor hallucis longus flexes the great toe and is located in the deep posterior compartment. The soleus and plantaris muscles are located in the superficial posterior compartment, just deep to the gastrocnemius muscles. The peroneus brevis is located in the lateral compartment. The tibialis anterior is located in the anterior compartment.
2016
A 24-year-old man is brought by ambulance to the emergency department after sustaining a tibial fracture in a motorcycle collision. On physical examination, there is an open, segmental fracture with a 4-cm wound and a large avulsion flap, but adequate soft-tissue coverage. Which of the following Gustilo-Anderson fracture classifications best describes this injury?
A) Type I
B) Type II
C) Type IIIA
D) Type IIIB
E) Type IIIC
The correct response is Option C.
2016
A 37-year-old postal worker is brought to the emergency department 2 hours after he sustained a crush injury to his right leg when his truck rolled downhill and pinned him to a wall. He reports progressive, intense burning pain of the right leg. On examination, the leg appears swollen and there is a tense woody feeling anterolaterally associated with severe tenderness on passive range of motion of the ankle. There is decreased sensation between the first and second toes. Palpable dorsalis pedis and posterior tibial pulses are noted. The difference between diastolic blood pressure and the anterior compartment pressure (delta pressure) is 15 mmHg. X-ray studies show no fracture. Which of the following is the most appropriate next step?
A) Perform emergency fasciotomy
B) Recheck anterior compartment pressure in 1 hour
C) Test electromyographic activity of the anterior tibialis
D) Test serum creatinine kinase activity
E) Wean analgesics to reduce variability in serial review
The correct response is Option A.
This patient is manifesting signs and symptoms of progressive acute compartment syndrome (ACS). ACS is a surgical emergency, and the next step in management is acute fasciotomy to fully decompress all involved compartments. Delays in fasciotomy increase unrecoverable tissue injury leading to permanent functional loss and morbidity such as muscle contractures, sensory deficits, paralysis, and infection.
Compartment syndrome occurs when increased pressures within unyielding fascial compartments lead to progressive cellular anoxic injury to tissues within the compartment. Symptoms of ACS include pain out of proportion to injury and deep aching or burning pain. Complaints of paresthesia suggest progressive ischemic nerve dysfunction. Signs of ACS include pain with passive ranging of muscles in the affected compartment, a tense compartment with a firm and indurated “woody” feeling, and diminished sensation.
Most cases of ACS occur with long-bone fractures, and risk increases with comminuted fractures. Other common forms of trauma including crush injury, severe thermal burns, constrictive bandages, penetrating trauma, vascular injuries, and ischemia-reperfusion injuries can lead to ACS. The anterior compartment of the leg is the most common site for ACS. Early signs of ACS affecting this compartment include loss of sensation in the distribution of the deep peroneal nerve, and weakness of dorsiflexion.
Normal compartment pressures fall between 0 and 8 mmHg. Pain develops as compartment pressures increase, and tissue ischemia occurs as compartment pressures approach diastolic pressure. Differences between diastolic blood pressure and measured compartment pressure (delta pressure) less than 20 to 30 mmHg indicate a need for fasciotomy.
As ACS evolves, muscle breakdown can lead to elevations in serum creatine kinase and myoglobinuria. Sensory deficits typically preclude motor deficits and EMG abnormalities progressing to total paralysis will occur. These are relatively late findings in ACS; they should not delay fasciotomy once progressive ACS is diagnosed.
There is no diagnostic role for withholding analgesics in extremity trauma.
2016
A 28-year-old man presents 8 days after open reduction and internal fixation of an unstable distal tibia fracture. Postoperatively, the incision has dehisced. Examination shows a 5 × 2-cm open wound with marginal skin necrosis and exposed hardware. Which of the following is the most appropriate next step in soft-tissue coverage?
A) Debridement with application of skin substitute
B) Hardware removal, casting, and wound care
C) Hyperbaric oxygen and wound care
D) Operative debridement and placement of a VAC for a bridge to skin grafting
E) Operative debridement and vascularized reconstruction with a flap
The correct response is Option E.
The best treatment that would allow salvage of the fracture fixation is operative debridement and vascularized flap reconstruction. Stable fixation has been achieved and subacute wound dehiscence has occurred because of ischemia or devitalization of the overlying soft tissue. This is due to the forces of the original trauma as well as potential further traumatic insult of the tissue during surgical repair. In the absence of infection, immediate soft-tissue reconstruction will provide stable vascularized soft-tissue coverage of the fracture site and the hardware. As such, vascularized flap reconstruction is appropriate. In the distal leg, this often requires free tissue transfer, but depending on the location and size of the defect, soleus flap or perforator propeller flaps can be used.
Gustilo provided a classification of open fractures of the leg in which the fracture site was exposed through a disruption of soft-tissue integrity:
Determination of the type of flap reconstruction required requires assessment of not only the location and size of the defect, but also the zone of injury. Greater degrees of force are associated with the increasing Gustilo classification such that type III fractures often require free tissue transfer because of concomitant damage of the regional and local tissues.
Operative debridement and placement of a VAC for a bridge to skin grafting is a potential treatment for an open wound with exposed bone without hardware. The period of time in which the wound remains open and granulates during this process provides a very high risk for hardware infection, nonunion, and osteomyelitis.
Debridement with skin advancement and closure is likely to fail because of the difficulty in providing appropriate tension-free advancement flaps in the leg, combined with the need to accommodate for tissue loss from the debridement and ischemia of the advancing skin edges. The reliability of this treatment is poor and would have high risk for failure and subsequent hardware infection and nonunion or osteomyelitis.
Hardware removal, casting, and wound care is not indicated since the fracture repair is intact and no signs of infection are present. However, if hardware removal were required because of overt infection, the most appropriate treatment would be placement of an external fixator and soft-tissue flap reconstruction.
Hyperbaric oxygen and wound care is not the best option in this acute situation in which prompt soft-tissue reconstruction and vascularized coverage of the fracture site are required to salvage the existent fixation and avoid mal/nonunion or osteomyelitis.
2016
An otherwise healthy 65-year-old man is evaluated because of a 2-month history of a nonhealing wound to the back of the left heel. He has a history of smoking 50 packs of cigarettes yearly but quit 1 year ago. Physical examination shows a clean wound with exposed bone and palpable distal pulses in the lower extremities. Coverage with a distally based fasciocutaneous sural flap is planned. Because of the patient’s history of smoking, a “delay” procedure is performed first. Division of which of the following is required for this procedure?
A) Distal greater saphenous vein
B) Distal lesser saphenous vein
C) Perforator 5 cm proximal to the lateral malleolus
D) Proximal greater saphenous vein
E) Proximal lesser saphenous vein
The correct response is Option E.
The surgical step required as part of the “delay” procedure in a distally based sural flap is division of the proximal lesser saphenous vein. The distally based sural flap is a neurofasciocutaneous flap used to reconstruct ankle, heel, and foot defects. The classically described and possibly most important arterial supply to the distally based sural flap is provided by septocutaneous perforators arising from the peroneal artery. The most distal of these is located 4 to 7 cm proximal to the lateral malleolus. However, there are at least three other sources described: fasciocutaneous perforators from the posterior tibial artery, venocutaneous perforators from the lesser saphenous vein, and neurocutaneous perforators from the sural nerve. The skin and fascia of the flap are drained primarily by the lesser saphenous vein. The lesser saphenous vein contains numerous valves that prevent retrograde blood flow. There are, however, one or more smaller collateral veins that run parallel to the lesser saphenous vein. These veins have anastomotic connections to the lesser saphenous vein, which can allow blood to bypass the valves of the lesser saphenous vein and flow in a retrograde fashion.
In attempts to redirect blood flow and decrease the risk of flap necrosis and other complications, several authors have described sural flap delay procedures. Two distinct delay procedures have been described. In one, the flap is first elevated without completely incising the proximal edge of the skin island. A powder-free glove is then placed between the elevated fascia and the gastrocnemius muscle, and the skin is closed. Two weeks later, the flap is completely elevated and transferred into the defect site. This procedure has the goal of redirecting blood flow in a longitudinal direction before complete elevation of the flap. In the other technique, the flap is raised in its entirety and then sutured back into its donor site. The flap is then transferred into its recipient site as a second procedure. This technique allows the flap to become viable on its distal vascular pedicle before causing the additional trauma of transferring the flap, which can potentially compromise that pedicle.
Division of the greater saphenous vein is not indicated because it is not in the vicinity of the flap. Similarly, division of the perforator 5 cm proximal to the lateral malleolus is not appropriate because this is the major pedicle supplying the flap.
2015
A 56-year-old man who is an active smoker sustains a degloving injury of the left foot from a motorcycle collision. The heel was avulsed from the calcaneus by a deep posterior laceration but has normal capillary refill. No tissue is missing, but the wound is heavily contaminated and the calcaneus has an abrasion that is imbedded with grit. After irrigation and debridement in the operating room, which of the following is the most appropriate next step in management of this wound?
A) Coverage with a free gracilis muscle flap
B) Healing by secondary intention
C) Layered closure over a drain
D) Negative pressure wound therapy and skin grafting
E) Serial debridement and delayed closure
The correct response is Option E.
The most appropriate management of this wound is serial debridement and delayed closure. With such a high level of contamination of both the soft and hard tissues, layered closure after the initial debridement will very likely lead to infection, especially in a patient with a history of smoking. It would be a mistake to perform a free tissue transfer in a highly contaminated wound. Furthermore, there is no missing or ischemic tissue. Negative pressure wound therapy followed by skin grafting would not be appropriate for a deep wound with bone exposure when local tissues are available for closure; this would be more appropriate for a superficial wound with missing skin. Healing by secondary intention is an option; however, serial debridement and delayed closure will take less time, is less painful, and avoids scar formation in the heel.
2015
A thin 40-year-old woman has an 8 × 5-cm skin defect in the distal third of the anterior leg extending to the dorsum of the foot, with tibia denuded of periosteum and exposed tendon, after undergoing stabilization of the fracture with internal hardware 3 days ago. The distal posterior tibial artery was ligated before surgery at the distal third of the leg. There are no signs of infection or osteomyelitis. Which of the following is the most appropriate method of reconstruction?
A) Application of bilaminate neodermis (Integra) and negative pressure wound therapy
B) Coverage with a dorsalis pedis flap
C) Coverage with a free anterior lateral thigh (ALT) flap
D) Coverage with a free tranverse rectus abdominus myocutaneous (TRAM) flap
E) Coverage with a reverse sural flap
The correct response is Option C.
A free anterior lateral thigh flap is large enough to close the defect, can be thinned for aesthetics and shoe wear, and may allow for primary closure of the donor site. Although free tranverse rectus abdominus myocutaneous (TRAM) flap coverage is a possibility, the potential complications of taking muscle and unpredictable control of the final contour make them less ideal options. The reverse sural flap is not an option because of the ligation of the posterior tibial artery. In addition to having severe donor site morbidity, the dorsalis pedis would remove the remaining blood supply to the foot. The vascular nature of the defect’s wound bed makes bilaminate neodermis (Integra) and negative pressure wound therapy a less optimal choice.
2015
A 15-year-old girl sustained an isolated open tibial fracture in a motor vehicle collision. At the proximal third of the tibia, 15 cm of anterior soft-tissue loss is noted. Despite fracture reduction, the foot is warm but pulseless without dopplerable signals. The patient is otherwise stable. Which of the following is the most appropriate next step in management?
A) Below-knee amputation
B) CT angiography
C) Four-compartment fasciotomy
D) Internal fixation and soft-tissue coverage
E) Surgical exploration of the popliteal artery
The correct response is Option B.
Lower extremity fractures with combined soft-tissue and neurovascular trauma have high rates of complications, and a percentage of these injuries lead to amputation. Risk factors for amputation include Gustilo IIIC injuries, sciatic or tibial nerve injuries, prolonged ischemia (more than 4 to 6 hours), significant soft-tissue injury, significant wound contamination, multiple injured extremities, advanced age, lower versus upper extremity trauma, and futile attempt at revascularization. While tibial nerve injury is a risk factor and relative indication for amputation, it is never an absolute indication for amputation.
Hard signs for vascular injury include: active hemorrhage, expanding hematoma, bruit or thrill, absent distal pulses, and distal ischemic signs and symptoms (five P’s). In the face of these hard signs, imaging such as CT angiography should be used to evaluate for vascular injury. With that said, most hard signs can be explained by soft-tissue or bone bleeding, traction of intact arteries due to unreduced fractures, or compartment syndrome.
Early soft-tissue coverage is associated with a lower complication rate. The goal is to close wounds within 7 to 10 days to decrease the risk for infection, osteomyelitis, nonunion, and further tissue loss.
It is best to get wound control prior to bone grafting, avoiding the risk of losing valuable limited bone; therefore, bone grafting is generally postponed until 8 to 10 weeks after soft-tissue wound coverage.
2015
A 20-year-old man has purulent breakdown 5 months after sustaining a Gustilo type IIIB open fracture treated with intramedullary rod placement and skin grafting over a medial gastrocnemius flap. A postoperative x-ray study and current photograph are shown. The intramedullary rod is removed and an external fixator is placed. There is 1.5 cm of bone without periosteum surrounding the fracture exposed in the wound. Which of the following is the most appropriate next step in wound reconstruction?
A) Full-thickness skin grafting with a bolster dressing
B) Reconstruction with an anterior tibial artery perforator flap
C) Reconstruction with a lateral gastrocnemius muscle flap and skin grafting
D) Reconstruction with a pedicled descending medial genicular artery flap
E) Split-thickness skin grafting with negative pressure wound therapy
The correct response is Option B.
Perforator flap reconstruction, whether free or pedicled, has become increasingly popular over the past decade. Perforator flap use allows for the creation of an axial pattern flap without the sacrifice of a major artery and can often be done for areas once considered to require free flaps for coverage. Prior transfer of a medial gastrocnemius flap might disrupt perforators from the posterior tibial artery to the medial leg skin, but would not have disturbed anterior tibial artery perforators through the skin of the anterolateral leg.
Skin grafting, whether split- or full-thickness, would not be successful on fractured bone without periosteum, regardless of the type of dressing used.
The lateral gastrocnemius muscle is smaller and cannot reach as far as the medial gastrocnemius. It would not be able to reach the mid-shaft tibia defect shown in this patient.
The descending medial genicular artery is the pedicle of the medial femoral condyle flap. It is normally used as a bone graft donor, although an overlying skin paddle can be harvested with it. When used in a pedicled fashion, it can be transposed proximally onto the thigh, but not distally onto the leg.
2015
A 35-year-old man is referred to the office after undergoing prolonged failed attempts at local wound care of an exposed Achilles tendon. Physical examination shows that the tendon is beginning to desiccate. Coverage with a flap is performed, as shown. The blood supply to this flap is derived from which of the following arteries?
A) Anterior tibial
B) Geniculate
C) Peroneal
D) Popliteal
E) Superficial femoral
The correct response is Option C.
The flap used to cover the Achilles tendon in the patient described is the reverse sural fasciocutaneous flap. It is based on perforators from the peroneal artery through a network of small vessels. The general axis of the flap follows the sural nerve from behind the lateral malleolus to the mid portion of the gastrocnemius muscle bellies. Sural nerve injury results in loss of lateral foot sensation. This is often of no functional consequence because its harvest does not result in loss of a major neurovascular structure.
The other vessels noted do not supply inflow to the flap.
2015
An otherwise healthy 30-year-old man is evaluated because of left foot drop after posterior knee dislocation. The common peroneal nerve is explored at the level of the knee shortly after the time of injury and found to be in continuity. The patient does not return for follow-up examination within the next year. Eighteen months after the injury, the patient returns for follow-up examination and shows no improvement of the foot drop. Passive range of motion of the ankle is full. Which of the following transfers is most likely to correct this patient’s foot drop deformity?
A) Peroneus brevis tendon with graft to calcaneus bone
B) Peroneus longus tendon to calcaneus bone
C) Peroneus longus tendon to talus bone
D) Tibialis anterior nerve to tibialis posterior nerve
E) Tibialis posterior tendon to tibialis anterior tendon
The correct response is Option E.
Common peroneal nerve injury is common after posterior knee dislocation, usually occurring at or near where the nerve crosses the fibula neck. After surgical exploration to confirm the peroneal nerve is intact, initial management consists of supportive care with an ankle brace to correct foot drop. Patients are observed clinically for recovery, often with serial electromyography and nerve conduction studies.
Tibialis posterior to anterior transfer will restore the patient’s ability to dorsiflex the ankle. The donor muscle is innervated by the tibial nerve, which is not commonly injured in a posterior knee dislocation. The tendon is dis-inserted from the tarsus and brought out through the medial leg.
(Please note that this pictorial appears in color in the online examination)
It is transferred through the interosseous membrane to the tibialis anterior tendon.
By 18 months after injury, the motor end plates to the tibialis anterior have degenerated, making a nerve transfer no longer an option. Earlier after injury, a nerve transfer from the tibialis posterior to the tibialis anterior might be a feasible option.
Peroneus longus and brevis would also be paralyzed in the setting of a common peroneal nerve injury such as this patient’s. In certain situations, such as with some patients with leprosy, the deep peroneal nerve is not paralyzed. For these patients, the peroneus longus can be used as a tendon transfer, but it is normally used to provide toe extension in conjunction with a tibialis posterior transfer to provide ankle dorsiflexion.
2015
A 57-year-old man comes to the office 4 weeks after undergoing a free osseocutaneous fibula flap. He says he has pain with walking. A photograph is shown. X-ray studies show 6 cm of fibular bone remains proximally and distally. Sensation of the right foot shows no abnormalities; pain is noted on plantar flexion. Which of the following is the most appropriate next step in management?
A) Cast immobilization of the lower extremity (above the knee)
B) Cast immobilization of the lower extremity (below the knee)
C) Operative exploration and bone grafting
D) Operative exploration and nerve grafting
E) Reassurance that the pain is self-limiting
The correct response is Option E.
Vascularized bone flap is typically needed for defects >6 cm regardless of location in the body. The fibula is a common donor for vascularized bone. Understanding the postoperative course and complications is needed both in terms of discussions with the patient preoperatively and management of the patient’s condition after surgery. Common sequelae of fibula harvest include pain in the leg (especially when walking). Four weeks is relatively early in the postoperative course and reassurance should be given.
Risks of fibula harvest include damage to the peroneal nerve (increased when <6 cm of bone is left behind or when the head of the fibula is included in the harvest); destabilization of the ankle (increased when <6 cm of bone is left behind); and damage to the posterior tibial nerve.
A free-fibular flap design with hash marks left intact is shown.
2014
A 32-year-old woman comes to the office because the toes of the right foot “drag” when she walks. She underwent vein stripping of the right leg and ligation of the lesser saphenous vein 4 weeks ago. Physical examination shows absent dorsiflexion and eversion of the ankle. Electromyography findings show:
Which of the following is the most likely site of nerve injury in this patient?
A) Common peroneal nerve at the knee
B) Superficial peroneal nerve at the knee
C) Sural nerve at the knee
D) Tibial nerve at the knee
E) Tibial nerve at the mid calf
The correct response is Option A.
The most likely site of injury would be the common peroneal nerve at the knee. Injuries to the common peroneal nerve are well documented in both traumatic (knee dislocation) and iatrogenic settings. Patients have footdrop and numbness over the first dorsal web space of the foot. History and clinical examination are the mainstays for diagnosis, but electromyography can be helpful in less-clear circumstances. The absence of recruitment of the lateral compartment muscles (peroneals) and the anterior compartment muscles (tibialis anterior, extensor hallucis longus) strongly suggest common peroneal involvement. The presence of recruitment of the biceps femoris and the tibialis posterior rules out tibial nerve involvement. An isolated superficial peroneal nerve injury would spare the anterior compartment muscles.
The sural nerve is a sensory nerve and provides no motor function.
2014
A 40-year-old man is diagnosed with a posterior thigh sarcoma. He undergoes resection of the tumor as well as some of the surrounding muscle. Partial sacrifice of the sciatic nerve is required, leaving a 40% circumferential defect and an 11-cm gap between proximal and distal ends. A photograph is shown. Which of the following is the most appropriate method of nerve reconstruction?
A) Mobilization and primary coaptation
B) Polyglycolic acid nerve tube
C) Processed human allograft conduit
D) Saphenous vein graft
E) Sural nerve cable graft
The correct response is Option E.
Fundamentals of nerve repair include coaptation in a tension-free manner. If there is any tension, nerve grafts or conduits are indicated. In this clinical scenario, there is a large nerve gap that precludes tension-free primary coaptation, even with extensive proximal and distal mobilization. Therefore, a nerve graft is indicated. Common choices include sural, lateral, or medial antebrachial cutaneous. For the size and length of the defect and the fact that multiple cable grafts would be needed, the sural is the most appropriate choice.
Nerve conduits such as PGA tubes and processed human allograft conduits serve as scaffolds to promote nerve regeneration, although these are typically used for gaps less than 3 cm. Given the distance involved, a sural nerve graft using a grouped fascicular or epineurial repair is the most appropriate choice, although a gap this large is almost certain to leave permanent deficits. Appropriate levels of expectation must be set with the patient.
2019
A 21-year-old man undergoes reconstruction with a free flap. Photographs are shown. This procedure places the patient at risk for claw toe with loss of active flexion of the great toe. The muscle responsible for this functional loss is located in which of the following compartments in the lower leg?
A) Anterior
B) Deep posterior
C) Lateral
D) Superficial posterior
The correct response is Option B.
Claw toe or loss of active flexion of the great toe interphalangeal joint can result from harvest of the flexor hallucis longus for free fibula flaps. The flexor hallucis longus is present within the deep posterior compartment of the lower leg and should be resuspended to the interosseus membrane and posterior tibial muscles as needed to maintain proper tension. Physical therapy is initiated after adequate wound healing to maintain the mobility of the great toe and ankle. The deep posterior compartment musculature is composed of the tibialis posterior, the flexor digitorum longus, the flexor hallucis longus, and the popliteus.
The superficial posterior compartment musculature is composed of the gastrocnemius, soleus, and plantaris.
The anterior compartment musculature is composed of the tibialis anterior, the extensor digitorum longus, extensor hallucis longus, and the peroneus tertius.
The lateral compartment musculature is composed of the peroneus longus and brevis muscles.
2019
A 48-year-old man presents to the emergency department because of spontaneous progressive pain, swelling, cyanosis, and edema of the left lower extremity for the past 24 hours. A photograph is shown. Medical history includes prophylactic inferior vena cava (IVC) filter placement in the setting of prolonged immobilization secondary to traumatic closed head injury sustained 2 years ago. Physical examination shows no dyspnea. Oxygen saturation is 98% on room air. Venous ultrasonography and CT scan show total left deep femoral thrombosis extending into the lower IVC at the indwelling filter. Which of the following is the most appropriate next step in management?
A) Catheter-directed thrombolysis
B) Femoral vein to IVC vascular bypass
C) Isolated extracorporeal membrane oxygenation (ECMO) support to the affected extremity
D) Open thrombectomy
E) Oral anticoagulation
The correct response is Option A.
The patient is presenting with extensive acute thrombotic occlusion resulting in clinically evident symptomatic venous insufficiency of the extremity. If the occlusion is left untreated, progressive cyanosis and secondary ischemia followed by gangrene develop. Locally delivered thrombolytic agents via catheter-directed thrombolysis with or without percutaneous transluminal angioplasty is an effective first line of treatment in this scenario where the patient presents within a few days of symptom onset (ie, prior to clot fibrosis) and is not high-risk for bleeding. In patients who are high-risk for bleeding (eg, acute intracerebral hemorrhage, gastrointestinal bleeding), alternative methods of restoring venous outflow include clot retrieval through other percutaneous or open techniques (eg, transluminal aspiration thrombectomy, open inferior vena cava (IVC) thrombectomy with or without temporizing groin arteriovenous fistula creation). Systemic thrombolysis can be considered when other first line therapies are not available but has been associated with high frequency of major bleeding complications in several randomized trials (14% for streptokinase).
Systemic anticoagulation infusion helps prevent progression but does not restore acute compromised ischemic limb secondary to venous outflow obstruction. Oral anticoagulation is not indicated for acute management of a limb-threatening thrombosis. Femoral vein to IVC vascular bypass is not a described procedure for venous insufficiency. Limb-threatening thrombo-occlusive venous insufficiency resulting in a painful swollen blue leg, such as that pictured (also known as “phlegmasia cerulea dolens,” literally “painful blue edema”) was first described with heparin-induced thrombocytopenia. It has also been associated with cancer or life-threatening critical illness. More recently, a growing population of patients are at risk due to unretrieved IVC filters. While IVC filter placement may protect the pulmonary vascular bed, it does not lessen thrombotic predisposition or incidence in the lower extremities, and IVC thrombosis with or without phlegmasia cerulea dolens has been reported to occur in 3 to 30% of patients following IVC filter placement. Filter retrieval following its initial indicated need can lessen secondary thrombotic complications, but data suggest that only a fraction of retrievable filters are later removed. In a systemic review, overall retrieval was 34% with a high percentage of nonretrieval occurring for a variety of reasons, including loss to follow up (particularly in trauma centers), limited life expectancy, and/or unresolved underlying conditions.
2020
A 25-year-old man presents with a comminuted tibia plateau fracture sustained during a self-inflicted gunshot wound. A CT scan is shown. During open reduction and internal fixation of the fracture, a 5-cm gap in the common peroneal nerve is noted. Tendon transfer, nerve repair with grafting, and nerve transfer are planned. Which of the following fascicular nerve transfers is most likely to aid in ankle dorsiflexion?
A) Flexor digitorum longus to soleus
B) Flexor digitorum longus to tibialis posterior
C) Flexor hallucis longus to tibialis anterior
D) Peroneal longus to extensor digitorum longus
E) Soleus to extensor digitorum brevis
The correct response is Option C.
Common peroneal nerve repairs tend to have less favorable results than their upper extremity counterparts. Traction injuries showed only good outcomes in 42% of patients, whereas sharp injuries showed good results in 61% of patients. Gunshot wounds, on the other hand, showed only 49% good outcomes due to the blast injury. This patient had damage of his nerve from penetrating trauma from the fracture fragments as well as damage from the blast injury. Because of the size of the defect, primary nerve repair would not be feasible. Nerve grafts less than 6 cm have been found to have a more favorable result than those greater than 6 cm. When combined with blast injury, a favorable result has only been found in 31% of patients.
In addition to nerve repairs, tendon transfers of the posterior tibial tendon have been useful for more immediate dorsiflexion. Fascicular nerve transfers have found some success in dorsiflexion. Of the options given, only transfer from the flexor hallucis longus (tibial nerve) to the tibialis anterior (deep peroneal nerve) would result in dorsiflexion. Although flexor digitorum longus is a common donor from the tibial nerve, innervating the soleus would result in plantar flexion and the soleus is also innervated by the tibial nerve, so it was not injured in the gunshot. Transfer from the flexor digitorum longus to the tibialis posterior (tibial nerve) would plantarflex the foot and not dorsiflex it. Although transfer to the extensor digitorum longus can lead to dorsiflexion, transfer from the peroneal longus (superficial peroneal nerve) to extensor digitorum longus would not result in a functional nerve repair, since the peroneal longus is innervated by the damaged nerve. Finally, transfer from the soleus to the extensor digitorum brevis (EDB, deep peroneal nerve) would not be a nearby transfer, nor would the EDB dorsiflex the ankle.
2022
A 20-year-old man presents to the emergency department 6 hours after a bicycle accident with an open tibial fracture. The patient was traveling at 10 miles per hour at the time of the accident. The wound is 5 cm in length, and there is moderate contamination. The fracture is a mid-shaft tibial fracture with moderate comminution, with an associated closed fibula fracture. Which of the following Gustilo classifications is most appropriate for this injury?
A) I
B) II
C) IIIA
D) IIIB
E) IIIC
The correct response is Option B.
Though it was never designed to predict treatment, the Gustilo classification has stood the test of time as a highly utilized grading system for lower extremity trauma. It is often used to predict the need for flap coverage, to estimate the risk for osteomyelitis, and to guide antibiotic use.
2022
A 46-year-old woman presents with new-onset pain following below knee amputation. Medical history includes a Gustilo IIIB left leg injury and failed limb salvage 3 years ago. The patient reports phantom sensation, pain in her great toe, burning that ascends the limb, and several points along the distal stump that are inappropriately tender.On examination, a well - healed amputation stump without evidence of unstable skin or skin changes consistent with pressure - related trauma is noted.Targeted muscle reinnervation surgery is planned. Which of the following is the most likely evolution of neuropathic pain at 4 weeks and 6 months postoperatively in this patient?
The correct response is Option C.
Targeted muscle reinnervation (TMR), as originally described by Dumanian and Kuiken, is a procedure in which sensory and/or mixed nerves are transferred or coapted to motor nerve branches, in an effort to promote organized nerve growth and also to improve prosthetic control. While initially explored for improvement of prosthetic functionality, researchers observed a concomitant reduction in neuropathic and residual limb pain.
Though more research is needed, targeted muscle reinnervation may be most successful in decreasing or preventing pain when performed at the time of the amputation. The natural history of pain following TMR performed secondarily (not at the time amputation) includes a period of immediate relief (nerves are cut proximal to the neuroma), followed by activation of the nerves and increased pain (3 to 6 weeks), and plateau and reduction of pain (6 weeks to 6 months).
Nearly all patients report a decrease in pain and improvement in quality of life. The degree with which the pain is decreased and life is improved may be related to the timing of the operation. Data suggest that the earlier the operation is performed, the better the results, perhaps because of the centralization of the somatic pain response, though more work is needed to elucidate this mechanism.
2022
A 38-year-old man is brought to the emergency department after he sustained a Gustilo Type IIIB injury to the distal left lower extremity in a motor vehicle collision. Photographs and an x-ray are shown. A free flap is planned for soft-tissue coverage, and a temporary antibiotic bone cement spacer is placed in the 5-cm bone gap. Which of the following is the optimal time for using this induction membrane technique to perform the second stage bone graft?
A ) 1 week
B ) 3 weeks
C ) 6 weeks
D) 12 weeks
The correct response is Option C.
The Masquelet technique (induction membrane technique) is an effective two-stage technique for managing large bone gaps (even greater than 20 cm). After appropriate debridement and soft-tissue coverage, the first stage involves meticulous debridement of the nonviable bone with placement of an antibiotic cement spacer to promote the creation of an organized pseudosynovial membrane rich in inductive molecules. During the second stage, the membrane is incised and cancellous bone graft is placed. The optimal time between the two stages is 4 weeks, but if delays are anticipated (especially with compromised vascularity or soft-tissues), the second stage can be performed at 6 to 8 weeks. The three largest published clinical series used 6 to 8 weeks for the second stage. At 1 to 2 weeks, the membrane has not formed adequately. Levels of growth factor release are lower before 4 weeks. After 4 weeks, the osteogenic capacity begins to decrease, so waiting 8 to 12 weeks has no advantage and may increase the risk for failure or nonunion.
2023
A 13-year-old boy is evaluated after undergoing debridement of calcaneal osteomyelitis by the orthopedic team. A photograph is shown. Reconstruction with a sensate anterolateral thigh flap is planned. Which of the following best describes the path of the nerve that should be harvested with this flap?
A) It arises from the common peroneal nerve
B) It branches from the tibial nerve
C) It descends through the fibers of the psoas muscle
D) It passes under the lateral aspect of the inguinal ligament
E) It pierces the gastrocnemius muscle
The correct response is Option D.
The lateral femoral cutaneous nerve (LFCN) of the thigh can be used to make an anterolateral thigh flap sensate. This flap is a good choice for a wound requiring some filling of dead space. In this patient, the LFCN was coapted to the sural nerve for sensory reconstruction. Photographs are shown. The anatomy of the LFCN is also important to understand when treating patients with meralgia paresthetica, or compression of the LFCN. The LFCN passes under the inguinal ligament, which can be a site of compression.
The gracilis muscle receives motor (not sensory) innervation from the obturator nerve, which descends through the fibers of the psoas muscle.
The sural nerve pierces the gastrocnemius muscle in the distal third. This is a commonly used nerve donor for graft reconstruction of nerve defects. It is also an important pedicle for the reverse sural flap (a nonsensate flap since the proximal nerve is divided in the harvest). It arises from the tibial nerve and the common peroneal nerve at the level of the knee.
The gastrocnemius muscle is commonly used for pedicled reconstruction of proximal third defects. This muscle receives motor (not sensory) innervation from branches of the tibial nerve.
The medial plantar artery flap can be harvested as a sensate flap, innervated by cutaneous branches of the tibial nerve. This flap is useful for small defects and would not be suitable for such a large wound.
2023
A 45-year-old man is evaluated because of an enlarging fluctuant mass over the posterior hip. Four months ago, he sustained injuries in a snowmobile accident. At that time, he received treatment for sacral and pubic rami fractures, but no skin injury was noted. The initial CT image is shown. Which of the following is the most likely cause of the deformity in this patient?
A) Fat necrosis
B) Hemorrhage
C) Lymphatic disruption
D) Postoperative seroma
E) Sarcoma
The correct response is Option C.
This is a Morel-Lavallée lesion (MLL), which can result from a shearing injury but also fromother forms of trauma. It occurs when the fascia is sheared away from the superficial subcutaneous tissues. This creates a prefascial plane which allows for a potential space to be filled from the leaking disrupted lymphatic vessels and capillaries.
The CT scan at time of injury shows the space filled with a hematoma. Although the blood typically resolves, the lymphatic fluid can continue to leak, causing surface damage and skin necrosis.
Fat necrosis would not worsen over time, although it can be present with this type of injury and can calcify. A hemorrhage, which would be present, would resolve over time, and it would not likely be the cause of skin necrosis or worsening this far out.
MLL can be confused with a postoperative seroma, but seromas generally don’t enlarge months after the procedure. MLL is also often seen with pelvic fractures, as in this patient.
MLL can also be confused with sarcomas, but they would be more fixed in nature and not fluctuant. There is no evidence of a tumor on the CT scan of the initial injury; the scan shows a large hematoma and shearing injury to the right hip. Although the blood has likely resorbed by now, the leaking lymphatic vessels would be the most likely cause of the increasing fluid collection.
The treatment of MLL varies, with aspiration and more conservative measures early on, followed by surgical excision of more recalcitrant lesions.
2023
