Hand Fractures and Dislocations Flashcards

Question

``` A 20-year-old man comes to the emergency department after falling on the thumb of the dominant right hand during basketball practice. The thumb remained in a “bent back position” despite the coach’s attempt to straighten it. Radiographs of the hand are shown and demonstrate a dorsal dislocation of the thumb. Which of the following is the most appropriate treatment? (A)Closed reduction (B)Dynamic traction splinting (C)Open reduction (D)Percutaneous pin fixation in flexion (E)Serial splinting ```

Answer 1

(A)Closed reduction The radiographs show a dorsal dislocation of the thumb. Most metacarpophalangeal (MCP) dislocations of the thumb are dorsal and are reducible. The standard technique is gentle hyperextension of the MCP joint with direct pressure on the dorsal base of the proximal phalanx.

Answer 2

Most metacarpophalangeal (MCP) dislocations of the thumb are dorsal and are reducible. The standard technique is gentle hyperextension of the MCP joint with direct pressure on the dorsal base of the proximal phalanx.

Answer 3

The standard technique is gentle hyperextension of the MCP joint with direct pressure on the dorsal base of the proximal phalanx. A median nerve block added to a radial nerve block allows the thenar musculature to relax and loosen its noose. Further wrist flexion can loosen the FPL.

Answer 4

The mechanism of the dislocation is a disruption of the volar plate, dorsal capsule, and portions of the collateral ligaments.

Answer 5

Reduction becomes more difficult when: 1. The volar plate becomes interposed between the metacarpal head and the proximal phalanx. Hyperextension helps extricate the volar plate and allow reduction. 2. Reduction can also be inhibited when the flexor pollicis longus (FPL) and the thenar musculature ensnare the metacarpal head like a noose.

Answer 6

Inside the volar plate

Answer 7

Observation of the location of the sesamoid bones, which are imbedded in the volar plate, will give evidence of the location of the disruption.

Answer 8

Open reduction is appropriate if closed reduction is unsuccessful using adequate anesthesia and appropriate reduction maneuvers.

Answer 9

Proponents of the dorsal approach avoid endangering the volar digital nerves, which are pushed very close to the skin by the metacarpal head. In contrast, the volar approach allows repair of the volar plate if needed.

Answer 10

(A)Closed reduction The critical element is reduction to alleviate the numbness and pain. Splinting follows successful reduction. The patient described has a closed right dorsal perilunate, transscaphoid, transulnar styloid fracture-dislocation. In the scenario described, with no immediate operating room availability and with worsening pain and numbness, the most appropriate treatment is closed reduction followed by splinting, which can be performed in the emergency department under conscious sedation. When an operating room becomes available, the injuries to ligament and bone can be open repaired or reconstructed

Answer 11

The critical element is reduction to alleviate the numbness and pain. Can reduce in the ED to alleviate pain before taking to the OR.

Answer 12

(C)Reduction and fixation The patient described has an avulsion of the flexor digitorum profundus (FDP) tendon from the distal phalanx, otherwise known as a jersey finger. This injury most commonly involves the ring finger.

Answer 13

Classification for avulsion of the flexor digitorum profundus (FDP) tendon from the distal phalanx, otherwise known as a jersey finger.

Answer 14

The ring finger

Answer 15

In type 1 injuries, the proximal FDP retracts to the palm. These injuries must be repaired within two weeks to avoid a tendon graft.

Answer 16

In type 1 injuries, the proximal FDP retracts to the palm. These injuries must be repaired within two weeks to avoid a tendon graft.

Answer 17

In Type 2 injuries, the tendon retracts to the level of the proximal interphalangeal (PIP), where it is usually maintained by a distal phalanx bone fragment by the A3 pulley.

Answer 18

Type 2 injuries can usually be repaired without the need for a graft iftreated within three months. However, over time, type 2 injuries can convert to type 1 injuries with proximal migration of the tendon to the palm.

Answer 19

In Type 3 injuries, the bone fragment prevents tendon retraction proximal to the A4 pulley. Type 3 injuries can usually be repaired without a tendon graft, at any time, even after three months.

Answer 20

In Type 3 injuries, the bone fragment prevents tendon retraction proximal to the A4 pulley. Type 3 injuries can usually be repaired without a tendon graft, at any time, even after three months.

Answer 21

3 months | However, over time, type 2 injuries can convert to type 1 injuries with proximal migration of the tendon to the palm.

Answer 22

A3: In Type 2 injuries, the tendon retracts to the level of the proximal interphalangeal (PIP), where it is usually maintained by a distal phalanx bone fragment by the A3 pulley.

Answer 23

A4: In Type 3 injuries, the bone fragment prevents tendon retraction proximal to the A4 pulley.

Answer 24

(D)Open reduction with rigid screw fixation with early protected motion Condylar fractures of the proximal phalanx are inherently unstable. The patient described has a displaced condylar fracture. The standard of care is open reduction and internal fixation with either screws or Kirschner wire. Screw fixation allows for early active range of motion. Percutaneous pinning or fixation with cannulated screws under C-arm control is a reasonable approach; however, it can be more difficult to obtain reduction using these techniques

Answer 25

Condylar fractures of the proximal phalanx are inherently unstable.

Answer 26

The standard of care is open reduction and internal fixation with either screws or Kirschner wire. Screw fixation allows for early active range of motion. Percutaneous pinning or fixation with cannulated screws under C-arm control is a reasonable approach; however, it can be more difficult to obtain reduction using these techniques

Answer 27

Nondisplaced condylar fractures can be treated with splinting alone. However, displacement is likely and radiographs must be taken frequently to monitor for displacement. Similarly, closed reduction can be performed, but frequent follow-up radiographs are needed

Answer 28

Skeletal dynamic traction splinting is appropriate for severely comminuted proximal interphalangeal (PIP) joint fractures such as those seen with pylon-type injuries

Answer 29

Skeletal dynamic traction splinting is appropriate for severely comminuted proximal interphalangeal (PIP) joint fractures such as those seen with pylon-type injuries

Answer 30

(B)Extension block splinting of the proximal interphalangeal joint After evaluation and radiography, the injury should be splinted in a protected position. A dorsal semiflexed splint should protect the PIP joint in a stable, reduced position. The dorsal splint, which blocks extension, protects the injured joint from further complications

Answer 31

The most common pattern involves the volar lip of the middle phalanx. With the stability of the PIP joint disrupted, the finger subluxes or dislocates dorsally.

Answer 32

After evaluation and radiography, the injury should be splinted in a protected position. A dorsal semiflexed splint should protect the PIP joint in a stable, reduced position. The dorsal splint, which blocks extension, protects the injured joint from further complications.

Answer 33

Buddy taping is useful for PIP joint collateral ligament injury. H

Answer 34

(B)Fracture dislocation of the proximal interphalangeal joint Operative treatment of a fracture dislocation of the proximal interphalangeal (PIP) joint is generally indicated when more than 30% to 40% of the volar articular surface is involved.

Answer 35

Operative treatment of a fracture dislocation of the proximal interphalangeal (PIP) joint is generally indicated when more than 30% to 40% of the volar articular surface is involved. With this fragment volume, the PIP joint is unstable and displaced.

Answer 36

Treatment options include open reduction and internal fixation, extension block pinning, or use of a dynamic traction device.

Answer 37

The technique relies on the fact that distraction of the finger will reliably reduce the fracture and restore the joint anatomy. It also allows the patient to move the joint during fracture healing, decreasing the incidence of PIP stiffness.

Answer 38

(A) Dynamic traction When intra-articular fractures of the phalanges are severely comminuted or unstable, traditional methods of operative fracture fixation or immobilization may have an unacceptably high rate of late joint stiffness. The dynamic traction method, however, combines movement and traction in the treatment of intra-articular fractures. Distal traction reduces and realigns the articular fragments by forces exerted on them through ligamentous attachments (ligamentotaxis). In severely comminuted articular surface fractures, open reduction may be impossible and ligamentotaxis the only way to achieve adequate fragment reduction. Movement under continuous traction also helps prevent joint stiffness and contracture.

Answer 39

When intra-articular fractures of the phalanges are severely comminuted or unstable, traditional methods of operative fracture fixation or immobilization may have an unacceptably high rate of late joint stiffness. Immobilization (splints, casts, or K-wire fixation) can hinder joint mobility by promoting the formation of intra-articular adhesions and extra-articular joint capsule contractures.

Answer 40

Distal traction reduces and realigns the articular fragments by forces exerted on them through ligamentous attachments

Answer 41

he dynamic traction splint is usually worn for six weeks, but this can vary from four to eight weeks, depending on the severity of the fracture.

Answer 42

(C) Lumbrical muscle, volar plate, and flexor digitorum profundus The lumbrical muscle, volar plate, and flexor digitorum profundus tendons are most likely interfering with reduction of the index finger dislocation. Dorsal dislocations are uncommon injuries that occur as a result of forced hyperextension. The membranous proximal portion of the volar plate ruptures and becomes interposed dorsally between the base of the proximal phalanx and the dorsal metacarpal head. Reduction can be accomplished by flexing the wrist, which loosens the flexor tendons, and then applying pressure, directed distally and volarly, to the base of the proximal phalanx. In patients with complex dislocations, open reduction is required because the volar plate lies in the joint space, blocking a successful closed reduction.

Answer 43

(E) Open reduction and miniplate fixation This 17-year-old boy has displaced, angulated transverse fractures of the metacarpal shafts of thering and small fingers. Closed reduction of the fractures and use of a hand-based splint for four weeks has not resulted in healing. Therefore, operative treatment is the most appropriate next step. Repeat closed reduction and application of a long arm cast are unlikely to result in a successful reduction or lead to fracture healing. Closed reduction and transcutaneous fixation with Kirschner wires may have been considered at the time of injury but are not appropriate four weeks later. Closed reduction and external fixation are indicated in patients with highly comminuted fractures with or without bone loss or fractures associated with soft-tissue loss

Answer 44

Operative treatment is the most appropriate next step. This includes exploration to debride any material surrounding the fragments and open reduction of the fractures with manipulate fixation

Answer 45

Lag screw fixation is appropriate for treatment of spiral and oblique metacarpal fractures in which the length of the fracture is at least twice the diameter of the bone. This technique is advantageous because it minimizes periosteal stripping

Answer 46

(D) Extensor pollicis longus The vascular supply of the ulna can be maintained by harvesting the distally based posterior interosseous flap with a cuff of the extensor pollicis longus muscle. In this patient who has a 2-cm segmental defect of the metacarpal, vascularized bone from the ulna is appropriate for single-stage reconstruction. Other reconstructive options include the radius, scapula, fibula, humerus, and iliac crest. The radial forearm flap may also be harvested as an osteocutaneous flap for reconstruction of the metacarpal. Although free iliac crest corticocancellous grafts can be used to reconstruct metacarpal defects, vascularized bone graft is often preferred instead if the defect is large or the soft-tissue envelope has poor quality. The extensor carpi radialis brevis and supinator muscles do not supply perforators to the ulna.

Answer 47

The vascular supply of the ulna can be maintained by harvesting the distally based posterior interosseous flap with a cuff of the extensor pollicis longus muscle.

Answer 48

To determine the cutaneous portion of the posterior interosseous flap, a line is drawn from the lateral epicondyle of the humerus to the ulnar head with the forearm in full pronation. The cutaneous branch of the posterior interosseous nerve, which must be incorporated in the flap, lies 1 cm distal to the midpoint of this line.

Answer 49

The posterior interosseous artery lies deep to the deep fascia, and the septum passes between the extensor carpi ulnaris and extensor digiti minimi. After the artery has been identified, the surgeon dissects distally to the supinator, taking care to identify and preserve the posterior interosseous nerve.

Answer 50

Posterior interosseous nerve

Answer 51

A 5-to 7-cm segment of bone can be harvested by dissecting through of a portion of the extensor pollicis longus while leaving a cuff of muscle attached to the bone.

Answer 52

(D) Flexion of the wrist with pressure on the proximal phalanx directed distally and volarly This patient has a simple dorsal subluxation or dislocation of the metacarpophalangeal joint of the index finger. The finger can be easily reduced by flexing the patient's wrist while applying pressure at the base of the proximal phalanx directed distally and volary. This relaxes the flexor tendons and allows the proximal phalanx to slide over the metacarpal head and into the properly reduced position.

Answer 53

Longitudinal traction with a 5-lb weight or extension of the wrist with unweighted traction at the proximal interphalangeal joint draws the volar plate dorsally, where it may become folded between the metacarpal head and the base of the proximal phalanx, resulting in an irreducible dislocation. Additionally, because the narrow metacarpal neck is surrounded by taut lumbrical muscle and flexor tendons, further traction will tighten these structures and prevent reduction.

Answer 54

(D) Flexor digitorum profundus tendon The flexor digitorum profundus tendon is the most likely cause of the failed closed reduction. In this patient, the condyle of the proximal phalanx has ruptured through the flexor digital sheath on the ulnar side of the flexor digitorum profundus and superficialis tendons. The flexion power of these tendons foreshortens the digit, causing a sling-like entrapment around the condyles of the proximal phalanx. This constricting structure tightens as the digit is distracted distally and the flexor tendons are blocked by the condyles.

Answer 55

1. The flexor digitorum profundus tendon may cause of failed closed reduction when the condyle of the proximal phalanx has ruptured through the flexor digital sheath on the ulnar side of the flexor digitorum profundus and superficialis tendons. The flexion power of these tendons foreshortens the digit, causing a sling-like entrapment around the condyles of the proximal phalanx. This constricting structure tightens as the digit is distracted distally and the flexor tendons are blocked by the condyles.

Answer 56

Appropriate management of this irreducible dorsal dislocation of the PIP joint involves regional blockade with sedation to loosen the tendons, thorough irrigation of the joint, and partial division of the A3 pulley, which will allow the condyles to move from beneath the flexor tendons

Answer 57

(D) Closed reduction and longitudinal pin fixation This patient has a type IV mallet injury in which greater than 30% of the articular surface of the distal phalanx has been avulsed. The most appropriate management of this patient's fracture is closed reduction and longitudinal pin fixation. Because most of the collateral ligament remains attached to the avulsed fragment, the distal phalanx is subluxed on the middle phalanx. In order to correct this deformity, closed reduction and longitudinal Kirschner wire immobilization or open reduction with a pull-out wire technique should be performed. This will restore articular congruity and reduce the subluxed joint, preventing the development of osteoarthritis.

Answer 58

Most type IV mallet injuries can be reduced with a closed technique alone; open reduction should be considered only if closed reduction cannot be achieved

Answer 59

The stack splint immobilizes the distal interphalangeal joint in extension, allowing healing of the avulsed tendon to the distal phalanx: - May be used for correction of a type I mallet injury in which the tendon is avulsed from the proximal dorsal base of the distal phalanx. - May be used following suture repair in a patient with a type II mallet injury, which manifests as an open laceration of the terminal extensor tendon.

Answer 60

The Salter-Harris classification describes fractures involving the epiphyseal plate in children. The degree of growth disturbance correlates directly with the level of fracture classification.

Answer 61

In type I fractures, the epiphysis is separated from the metaphysis; the diaphysis and articular surface are unaffected.

Answer 62

Type II fractures involve a small fracture of the metaphysis and separation of the epiphysis from the metaphysis.

Answer 63

In type III fractures, the epiphysis is fractured and the articular surface is involved.

Answer 64

Patients with type IV fractures have involvement of the diaphysis, epiphyseal plate, and articular surface.

Answer 65

In type V fractures, the epiphyseal plate is compressed; the metaphysis is unaffected

Answer 66

In children with Salter-Harris type I fractures, appropriate management is closed reduction, followed by casting or pin fixation.

Answer 67

In children with Salter-Harris type II fractures, appropriate management is closed reduction, followed by casting or pin fixation.

Answer 68

(D) Open reduction Open reduction is the most appropriate management of this patient's deformity. These findings are consistent with a classic Stener lesion, in which the ulnar collateral ligament (UCL) avulses and retracts proximally. The interposed adductor aponeurosis precludes primary healing; the UCL will not heal properly without contact at the site of avulsion. Avulsion of the UCL can occur with or without a bony fragment. A mass can be palpated. Laxity of the ulnar capsule will occur and will notimprove with immobilization of the fracture, resulting in chronic pain and instability.

Answer 69

The ulnar collateral ligament (UCL) avulses and retracts proximally.

Answer 70

In a Stener lesion, the ulnar collateral ligament (UCL) avulses and retracts proximally. The interposed adductor aponeurosis precludes primary healing; the UCL will not heal properly without contact at the site of avulsion.

Answer 71

Laxity of the ulnar capsule will occur and will not improve with immobilization of the fracture, resulting in chronic pain and instability.

Answer 72

Open reduction and internal fixation should be performed to effectively restore contact between the fracture fragments and allow the fracture to heal.

Answer 73

In patients who have partial tears of the UCL, operative repair is indicated if collateral ligament instability is greater than 30 degrees during stress in both full extension and semi-flexion. Conservative management is recommended instead for incomplete ligament tears not associated with instability.

Answer 74

Appropriate surgical repair of this injury includes debridement of the fracture fragment, division of the adductor aponeurosis, and anchoring of the residual UCL to the small area of decorticated proximal phalanx using sutures. The adductor aponeurosis is repaired after the UCL is attached. The repaired ligament can be protected with a transarticular Kirschner wire and a cast for four weeks. After the cast is removed, a thumb spica splint should be worn for four weeks

Answer 75

(B) Capsulectomy In patients who develop flexion contractures following PIP joint injury, early management will result in optimal return of function. Serial casting is recommended for patients who have PIP joint contractures of greater than 30 degrees; dynamic splinting is used subsequently. Controlled application of 100 g to 250 g of torque will stretch the soft tissues Because treatment of this patient's severe posttraumatic flexion contracture has been delayed, the most appropriate management at this time involves release of the scarred soft tissues. The collateral ligaments, volar plate, capsule, and check rein ligaments of the PIP joint should be evaluated and then released sequentially. Capsulectomy is recommended to improve active motion of the finger.

Answer 76

Serial casting is recommended for patients who have PIP joint contractures of greater than 30 degrees; dynamic splinting is used subsequently. If timely treatment is delayed, the most appropriate management involves release of the scarred soft tissues.

Answer 77

For delayed treatment: The collateral ligaments, volar plate, capsule, and check rein ligaments of the PIP joint should be evaluated and then released sequentially.

Answer 78

(D) Repair of the lateral band

Answer 79

This patient has a volar rotary dislocation of the proximal interphalangeal (PIP) joint, an injury that is often described as irreducible.

Answer 80

This type of dislocation occurs following partial rupture of the volar plate, collateral ligament, and accessory collateral ligament; the flared ipsilateral condyle of the proximal phalanx often becomes entrapped between the central slip and lateral band in a "buttonhole" manner. The fragmented fibers of the lateral band become trapped beneath the flare of the condyle and redirected through the PIP joint.

Answer 81

However, in the majority of patients who have this type of injury, open repair should be considered. During this procedure, the fragmented lateral band should berepaired and properly aligned, and the central slip should also be repaired.

Answer 82

The usual maneuver for obtaining closed reduction, which involves traction and extension of the middle phalanx, actually tightens the encirclement around the condyle and ultimately leads to loss of the reduction. In some patients, closed reduction may be maintained by flexing the metacarpophalangeal and PIP joints, which relaxes the volarly displaced lateral band; a rotary motion can be used to re-establish congruity between the proximal and middle phalanges.

Answer 83

C) Hinge The metacarpophalangeal (MCP) joint of the thumb and interphalangeal joints of the index through little fingers are hinged joints and allow flexion and extension only. Lateral forces can disrupt the collateral ligaments, resulting in partial or full tears. Condyloid joints allow flexion and extension, abduction and adduction, and circumduction, and they can be seen in the MCP joints of the index through little fingers and in wrist joints. Saddle joints allow flexion and extension, abduction and adduction, and circumduction, and they can be seen in the carpometacarpal joint on the thumb. Ball-and-socket joints allow flexion and extension, abduction and adduction, and internal and external rotation, and they can be seen in the shoulder and hip joints. Pivot joints allow rotation and are seen in the atlas and axis bones.

Answer 84

Condyloid joints allow flexion and extension, abduction and adduction, and circumduction

Answer 85

the MCP joints of the index through little fingers and in wrist joints

Answer 86

Saddle joints allow flexion and extension, abduction and adduction, and circumduction

Answer 87

they can be seen in the carpometacarpal joint on the thumb

Answer 88

Ball-and-socket joints allow flexion and extension, abduction and adduction, and internal and external rotation

Answer 89

they can be seen in the shoulder and hip joints

Answer 90

B) Cancellous autograft The material that will most likely provide osteogenesis is cancellous autograft. Bony defects can be constructed by a variety of methods, and there has been an increase in the number of biomaterials that can be used. Autograft bone is obtained from the same individual, while allograft bone is obtained from another human source (i.e., cadaveric or donor). Demineralized bone matrix does not contain calcium, but retains growth factors and proteins as the nonmineralized components of bone. Calcium hydroxyapatite is a bone substitute that mimics bone in mineral structure, and gradually becomes replaced with native bone. Methylmethacrylate is used in orthopedic bone cement, and is not biodegraded or replaced, but can provide rapid structural support. Osteoconduction refers to the replacement of the graft material through a process known as creeping substitution, where native cells from the surrounding bone break down the material and replace it with new bone. This is the primary mechanism of healing of cortical bone grafts. It is also seen in biocompatible materials that are replaced with bone, such as calcium hydroxyapatite. Osteoinduction refers to the stimulation of bone-forming cells from surrounding host tissues, resulting in activation of progenitor cells and differentiation into osteoblasts, leading to the creation of new bone. This process occurs due to growth factors that are present in the graft material, and can be seen in cancellous bone grafts, as well as demineralized bone matrix, which contains growth factors. Osteoinduction also occurs with cortical grafts, although to a lesser extent. Osteogenesis refers to new bone formation, which is provided from surviving cells within the graft material. In order for osteogenesis to occur, viable cells must be transferred with the graft. This is seen in autograft materials, but not in allograft materials, which are processed and may be decellularized. Cells contained within autografts can survive and produce new bone. Vascularized bone transfer may give rise to more cell viability than traditional autografts, because it maintains perfusion to the grafted bone, rather than relying on nutrients from the bed.

Answer 91

C) Open reduction, repair of nail bed, and Kirschner wire fixation This patient has a Seymour fracture, or an open physeal/juxta-epiphyseal fracture of the distal phalanx. These injuries present as mallet-like injuries, but they are open fractures by definition. The treatment of choice is open reduction, debridement of the fracture site, repair of associated nail bed laceration, and Kirschner wire fixation of the fracture across the distal interphalangeal (DIP) joint. The injury is secondary to hyperflexion and is essentially a Salter I or Salter II fracture of the distal phalanx. The flexed posture occurs because the terminal extensor tendon inserts on the proximal dorsal epiphysis, while the flexor digitorum profundus inserts on the metaphysis of the bone distal to the fracture site. These injuries can often be mistaken for mallet injuries or DIP dislocations. Often a flap of nail bed matrix becomes interposed between the fracture fragments, preventing closed reduction. This must be repaired. It is recommended to not discard the nail plate, because it helps maintain bone reduction. Dorsal physeal widening and flexion of the distal fracture fragment is seen on lateral x-ray studies.

Answer 92

open physeal/juxta-epiphyseal fracture of the distal phalanx. These injuries present as mallet-like injuries, but they are open fractures by definition. The treatment of choice is open reduction, debridement of the fracture site, repair of associated nail bed laceration, and Kirschner wire fixation of the fracture across the distal interphalangeal (DIP) joint.

Answer 93

E) No functional impairment Vascular impairment related to pediatric supracondylar fractures occurs in roughly 5 to 10% of patients. Given the nontrivial morbidity of exploration of the brachial artery after reduction of the supracondylar fracture, controversy exists over what criteria should prompt surgical intervention. Recent large, retrospective studies have demonstrated that absence of pulses in the wrist after reduction is not, by itself, associated with poor outcomes. Most patients who lack pulses immediately after reduction, but who have an otherwise perfused hand, go on to recover a palpable radial pulse within 24 to 48 hours after the reduction. In this patient with a perfused hand, observation can be expected to result in a good outcome. Physeal arrest can occur secondary to ischemia, but this would not be the expected outcome based on the perfusion of the hand. Fibrosis of the deep flexor compartment (Volkmann ischemic contracture) is associated with compartment syndromes but would be rare in this setting. Median nerve impairment associated with the vascular insufficiency at the time of injury is advocated as an indication for surgical exploration. Development of a new median palsy as a late result of the vascular injury is unlikely. Rare case reports of late development of ischemia in the forearm and hand occur, and families should be counseled to watch for color or temperature changes in the hand following discharge after the recommended observation period of 24 to 48 hours.

Answer 94

C) Hemi-hamate arthroplasty Proximal interphalangeal (PIP) joint fracture dislocations are common finger injuries that result in pain and loss of motion. Normal PIP joint range is 0 to 110 degrees. This type of injury normally results from an axial load applied to the finger in a hyperextended position. If more than 30 to 50% of the volar base of the middle phalanx breaks off, the joint will become unstable. If identified early, the fracture can be managed with either open reduction and internal fixation or dynamic external fixation. At 6 weeks post injury, the fracture fragments would not be mobile, making dynamic external fixation unsuccessful. In addition, it is normally not possible to mobilize the fracture fragments in a manner that they can be reduced and fixated this far out from injury. Silicone implant arthroplasty can provide pain relief and preserve limited PIP motion in low-demand patients such as those with rheumatoid or osteoarthritis. It would not be sufficiently durable to tolerate the lifestyle of this patient and does not provide as much range of motion as a hemi-hamate graft. Arthrodesis will provide durable stability and pain relief even in a young patient. However, it sacrifices all motion at the PIP joint. As such, it should be reserved as a salvage option if motion-preserving options fail. Since its description by Hastings in 1999, hemi-hamate arthroplasty has become a reconstruction of choice for unstable late dorsal fracture-dislocations, particularly those involving more than 50% of the articular surface. The dorsal central portion of the hamate is harvested as an osteocartilaginous graft. Due to the thicker articular cartilage of the distal hamate compared with the base of the middle phalanx, the bone surfaces may appear uneven even though the cartilage surface (and, therefore, the joint surface) is confluent.

Answer 95

B) Distal radius Distal radius fractures usually occur in adults older than 40 years and are more common in women than in men due to the higher incidence of osteoporosis in women. The most common mechanism is a fall on an outstretched hand. After distal radius fracture, the next most common fracture of the wrist is scaphoid, followed by triquetrum, trapezium, and lunate.

Answer 96

D ) Interpose an autologous bone graft In a patient with a noncritical (less than 6- to 8-cm) bone defect of the hand, reconstruction with an autologous bone graft provides the best combination of maximal healing and minimal morbidity. To provide the best chance of successful healing, the graft should allow rigid stabilization. Corticocancellous grafts from the iliac crest are the typical source. Free vascularized bone flaps, such as the fibula, are essential tools when dealing with critical bone defects (greater than 6 to 8 cm). They do, however, add significant morbidity to the procedure and may not be feasible in individuals with severe peripheral vascular disease. In this patient, the noncritical defect would argue against the need for vascularized bone. Distraction osteogenesis works well for bone defects ranging from 1.5 to 13.5 cm. A prerequisite, however, is adequate bone stock to allow pin placement for the distractor. In this case, a 4-cm defect would leave insufficient bone at the metacarpal base and head to allow distractor placement. Calcium phosphate cement (Norian, Synthes) offers an osteoconductive substrate in bone defects that are already stabilized. In addition, its use is contraindicated in infected or potentially infected wounds. Demineralized bone matrix is osteoinductive, but, like calcium phosphate cement, will not offer any structural stability.

Answer 97

D ) Third metacarpal neck fracture with 25-degree angulation Angulation is better compensated for in the ring and little fingers. The carpometacarpal (CMC) joints of these digits have 20 to 30 degrees of mobility in the sagittal plane. Angulation deformities in the little finger up to 40 to 70 degrees have been followed and found to have no functional impairment. However, because of the lack of compensatory CMC motion in the index and long metacarpal neck fractures, there is universal agreement that residual angulation greater than 10 to 15 degrees should not be accepted. Metacarpal shaft fractures generally require reduction for angulation greater than 30 degrees in the little finger, 20 degrees in the ring finger, and any angulation in the long and index fingers.

Answer 98

D ) Open reduction and internal fixation The clinical scenario, photograph, and x-ray studies demonstrate classic symptoms of a ?jersey finger,? or avulsion of the insertion of the flexor digitorum profundus (FDP) tendon. In this instance, the rupture involves a large bone fragment to which the FDP tendon remains attached (Type III). The large size of the bone fragment lends itself to repair via open reduction and internal fixation of the fracture. Use of mini-screws or transosseous wiring will provide suitable internal fixation. Type II (retraction of the tendon to the proximal interphalangeal [PIP] joint) and Type I (retraction to the palm) injuries can be addressed through transosseous suture reattachment or suture anchor. Inadequate closed reduction would make percutaneous pin fixation a poor choice of treatment. Arthrodesis offers a salvage procedure for failed or unrepaired FDP avulsion injuries. In this young patient with an acute condition, arthrodesis would be too aggressive an intervention. Extension block splinting can be useful in volar plate injuries, which are often identified by a small, palmar avulsion fragment seen on the lateral x-ray study. This fracture would not be successfully reduced by attempts at flexion or splinting. Volar plate arthroplasty can restore a functional articular surface following intra-articular fractures of the PIP joint but are not useful in the DIP.

Answer 99

B ) Extension block splinting If the PIP fracture/dislocation can be maintained stable with 30 degrees of flexion, then this is suitable to treat by extension block splinting. This will be the case with an approximate 40% volar articular fracture of the base of the middle phalanx. There is a risk of late flexion contracture if greater than 30 degrees of flexion is required to maintain PIP joint stability. More complex injuries may be treated with force-coupler dynamic splinting or with hemi-hamate reconstruction. For a larger fracture fragment with greater instability, open reduction and internal fixation may be required. Volar plate arthroplasty may be suitable with more chronic injuries and is limited to 60% of the articular surface.

Answer 100

C) Flexor tendons and intrinsic muscles Dorsal metacarpophalangeal joint (MCP) dislocations are relatively uncommon. They occur with forced hyperextension injuries. The digit involved most commonly is the index finger, followed by the little finger. With complete dislocation, the volar plate ruptures in the membranous proximal portion and becomes interposed in the joint. If this were the only structure blocking reduction, traction on the joint would be sufficient to draw the proximal edge of the volar plate over the metacarpophalangeal head. This is not possible in an irreducible MCP dislocation because additional taut medial and lateral structures are drawn around the narrow metacarpophalangeal neck. At the index finger, the structures include the lumbrical on the radial side and the flexor tendons on the ulnar side. At the little finger, the structures are the common tendon of the abductor digiti minimi and flexor digiti minimi on the ulnar side and the lumbrical and flexor tendons on the radial side. Central slip remains dorsal at the proximal interphalangeal joint and is not associated with the metacarpophalangeal joint. The other structures at the MCP joint would not result in a noose around the metacarpal neck and block reduction.

Answer 101

B) Application of a thumb spica splint The patient described may have a scaphoid fracture that is not apparent on initial x-ray studies. Prudent management involves placement of a thumb spica splint until definitive diagnosis can be made. Repeating x-ray studies in 2 weeks or obtaining further radiologic studies, such as CT scans, can make the definitive diagnosis. Casting would be suboptimal in an acute injury such as this because soft-tissue swelling can cause constriction. Surgical exploration is not warranted at this time. A wrist-control, sugar-tong, or ulnar gutter splint would not adequately immobilize the scaphoid, and therefore, would not be adequate management. Acute scaphoid fractures can often be missed on initial x-ray studies, with reported sensitivities ranging from 84 to 98%. When clinical suspicion of a scaphoid fracture is high and plain films are negative, the traditional recommendation is for these patients to be immobilized in a thumb spica splint or cast with repeat x-ray studies after about 2 weeks. Even on the repeated x-ray study after 10 to 14 days propagated by many clinicians in cases of occult fracture, a scaphoid fracture is often missed since the additional sensitivity is low, although in a case of sclerosis, an x-ray study could confirm the suspected diagnosis. Further studies that may confirm the diagnosis include CT scan, MRI, and bone scan.

Answer 102

B) Genicular The descending genicular artery is the arterial pedicle for the medial femoral condyle free vascularized osseous corticoperiosteal free flap, or free vascularized bone graft. Scaphoid nonunions with a humpback deformity, carpal collapse, and proximal pole osteonecrosis are difficult to treat. Vascularized bone grafts have been shown to have nearly 2× the union rate of traditional nonvascularized bone grafts. Vascularized corticocancellous bone has the potential to revascularize necrotic bone and can provide structural support for fractures with loss of height of the scaphoid. Studies have shown superior union rates for the medial femoral condyle vascularized bone graft versus pedicled grafts from the distal radius. Anatomical studies show no clinical loss of stability of the femur after flap harvest. The peroneal artery is the blood supply of the fibular osseous or osteocutaneous free flap. It is generally reserved for head and neck reconstruction and larger defects of the extremities. The descending branch of the lateral femoral circumflex artery supplies the anterolateral thigh free flap. The dorsalis pedis artery supplies the dorsalis pedis fasciocutaneous flap. The medial sural artery and its perforators supply the medial gastrocnemius muscle, and musculocutaneous and fasciocutaneous flaps. All of these flaps are used for soft-tissue defects alone and are not appropriate for reconstruction of bony defects.

Answer 103

B) Dynamic scapholunate instability This patient has dynamic scapholunate instability. These injuries can be difficult to diagnose and require a high index of suspicion. A normal x-ray study at 12 weeks in the setting of these clinical findings suggests there is a disruption of the scapholunate interosseous ligament (SLIL) that is symptomatic only with mechanical loading. The SLIL is the primary stabilizer of the scapholunate joint, but it is surrounded by multiple secondary stabilizers consisting of the extrinsic wrist ligaments. Normal kinematic motion of the proximal carpal row is controlled by the tough interosseous ligaments. The dorsal component of the SLIL is the primary restraint to distraction, torsion, and translational forces. Disruption of the dorsal SLIL alone will result in changes in wrist mechanics, but the presence of the intact secondary stabilizing ligaments will prevent changes seen on a normal static x-ray study, such as scapholunate dissociation or an increased scapholunate angle. Stress view x-ray studies, such as the clenched-pencil view, should be obtained when dynamic instability is suspected in the setting of a normal static x-ray study series. These results can be compared with the contralateral normal side. Non-contrast MRI is an advanced imaging modality averaging 71% sensitivity, 88% specificity, and 84% accuracy for SLIL tears. There is improved accuracy with 3.0T MRI machines. Wrist arthroscopy is the gold standard for diagnosis and can be combined with therapeutic procedures such as debridement or thermal shrinkage. An occult scaphoid fracture should be visible at 12 weeks following the injury. Bone resorption at the fracture site makes the fracture line generally visible within 14 days. If suspicion remains for an occult scaphoid fracture at 2 weeks, additional imaging such as MRI or CT scan is indicated. At 3 months following the injury, any fracture present should be visible and treated as a non-union of the scaphoid. De Quervain tenosynovitis is defined as tendinitis of the first dorsal extensor compartment. This condition generally presents with pain and tenderness over the radial styloid with a positive Finkelstein test. Tenderness of the carpal bones and carpal bone instability such as a painful “clunk” would not be present. The condition is most associated with repetitive use and not acute trauma. Kienböck disease involves collapse of the lunate due to vascular insufficiency and avascular necrosis. Etiology is unknown but may involve a combination of anatomic factors and trauma. Early symptoms are similar to a wrist sprain but involve more global wrist pain, loss of dorsiflexion, and tenderness of the dorsal wrist over the lunate. Early stage I disease can have normal x-ray studies but will often show signs of a lunate fracture. Later stage disease shows sclerosis and ultimately fracture or collapse of the lunate. Flexor carpi radialis (FCR) tendinitis is not a common diagnosis. It presents with wrist pain, crepitus, and point tenderness over the FCR at the wrist flexion crease with flexion and radial deviation. Although it is a cause of radial-sided wrist pain, findings of carpal bone instability on examination are not present.

Answer 104

D) MRI The imaging study that is most sensitive and specific for detecting an acute scaphoid fracture is MRI. Many authors have written about the best secondary imaging study for scaphoid fractures not evident on standard x-ray studies. MRI is the best test considering both sensitivity and specificity, followed by CT scan. The majority of the published data shows bone scan to be the most sensitive but less specific than MRI or CT scan. Ultrasonography is used for evaluation of long bone fractures but is not yet indicated for evaluation of carpal bone fractures.

Answer 105

A) Capitolunate The capitolunate articulation should be intact in order to perform proximal row carpectomy. The patient described has a chronic scapholunate tear, which if left untreated, can lead to the consequences of scapholunate advanced collapse (SLAC) wrist. With ongoing progression, degenerative wrist arthritis and pain result. Arthritis occurs in a predictable sequence, initially at the radioscaphoid joint, followed by the scaphocapitate joint and the capitolunate joint. The radiolunate joint is typically spared until advanced stages. Proximal row carpectomy is a salvage wrist procedure that can be used in some cases of SLAC wrist. The proximal carpal bones of the wrist (scaphoid, lunate, and triquetral) are removed, and the capitate head is allowed to rest in the lunate fossa of the radius. In order for this procedure to be successful, the capitolunate joint should be free of arthritis. The patient should have preservation of cartilage on the capitate head and the lunate fossa of the radius, as this forms the new articulation of the wrist.

Answer 106

E) Triquetral The triquetral is the second most commonly fractured carpal bone. Most triquetral fractures are dorsal ridge fractures that appear as avulsion fractures on lateral view wrist x-ray studies. The most common carpal bone fracture incidences in order of frequency are scaphoid, triquetral, trapezium, lunate, and hamate.

Answer 107

D) Scapholunate ligament All the other answers are incorrect due to incorrect sequence of force transmission across the wrist. Furthermore B and E are wrong due to incorrect mechanism, as well. Wagner and Mayfield conducted classic studies on carpal dynamics and anatomy to determine the progression of stresses across the wrist in severe hyperextension injuries. They determined that there is a reliable and predictable pattern to these injuries, which is described as Progressive Perilunate Instability (PLI). There are four stages of PLI, corresponding to the degree of stress applied in the injury. The mildest form is the isolated scapholunate dissociation: PLI stage 1. As the forces continue in an ulnar and distal direction, the distal row and scaphoid progress dorsally, and the capitate separates from the lunate: PLI stage 2. As the force continues in an ulnar direction, the lunotriquetral ligaments separate, and if the lunate is still in place, this is the full Midcarpal Dislocation: PLI stage 3. Finally, in the most severe cases, the dorsally dislocated capitate will dislodge the lunate and push it volarly, creating the true lunate dislocation: PLI stage 4.

Answer 108

Treatment of a scaphoid malunion or “humpback” nonunion deformity by means of an opening interposition wedge bone graft is indicated when the lateral intrascaphoid angle is greater than 45 degrees. The intrascaphoid angle is determined by drawing a line tangent to the dorsal cortex of the distal fragment and the palmar cortex of the proximal fragment. Normally, this angle is 30 to 40 degrees. Amadio and coworkers reported on 45 patients with 46 scaphoid fractures greater than 6 months after healing. There were good clinical outcomes in 83% of those with intrascaphoid angles less than 35 degrees, and posttraumatic arthritis in 22%. In contrast, in those with greater than 45 degrees of lateral intrascaphoid angulation, only 27% had good outcome, and 54% developed posttraumatic arthritis. Nakamura and colleagues performed volar wedge bone grafting on seven symptomatic patients with scaphoid malunion, and all improved their symptoms. References

Answer 109

E) Trapezial resection, ligament reconstruction, and tendon interposition Thumb basilar joint arthritis is a common debilitating problem. The prevalence in postmenopausal women has been estimated at 33%, although many patients with radiographic evidence of arthritis remain asymptomatic. It more often occurs in the dominant hand. The extent of arthritis and joint deformity dictates the best treatment choice. The most widely used classification is that of Eaton and is based on radiographic findings. Stage I has normal joint contours but possible joint widening due to effusion. Although most patients respond to splinting, anti-inflammatory medications, trapezial hemi-resection, and metacarpal osteotomy have been advocated in very symptomatic patients. Stage II shows slight trapeziometacarpal (TM) joint narrowing and minimal sclerosis of the articular surface. The indications for operative treatment are more concrete, and surgical options are largely the same as Stage I, with the addition of CMC fusion as an option in a laborer. Stage III presents as TM joint narrowing with cystic or sclerotic changes in the articular surface. There is variable dorsal subluxation of the TM joint, and adduction contracture may occur. There can be early signs of scaphotrapezial (ST) joint arthritis. If the ST joint is in relatively good condition, some authors still advocate trapezial-sparing procedures such as hemi-resection. Nevertheless, most advocate trapeziectomy with or without ligament reconstruction/tendon interposition (LRTI). There is some evidence that ligament reconstruction preserves the joint space better than no reconstruction, but provides no better clinical outcome and has a higher complication rate. Trapeziectomy ± LRTI provides excellent pain relief and improved function, especially in lower demand patients. In Stage IV, the TM and ST joints are completely destroyed. In these patients, LRTI is the preferred treatment. Some authors report good early results in selected patients with implant arthroplasty; however, there is a moderately high rate (up to 40%) of instability, dislocation, and implant breakage. The use of silicone as a spacer has fallen into disuse due to the risk of chronic tissue inflammation and resultant bone resorption.

Answer 110

A ) Hook of the hamate fracture Specialized views of the wrist can provide better information regarding bony relationships and fractures, in addition to standard anteroposterior, lateral, and oblique films. There are many different specialized views that the plastic surgeon should be familiar with. Among these are the scaphoid, stress, and carpal tunnel views. The carpal tunnel view is a hyperextended wrist view displaying the carpal bone to carpal tunnel relationships. This view allows visualization of the hook of the hamate and the pisotriquetral joint, as well as the palmar surfaces of the trapezium, pisiform, and triquetrum.

Hand Fractures and Dislocations Flashcards

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