Ch 51 fractures of the humerus Flashcards

Question

proximal normograde insertion, the pin is usually started from the craniolateral aspect of the greater tubercle For fractures involving the mid- or proximal diaphysis, the pin is driven distally to a point just proximal to the supratrochlear foramen.

Answer 1

For retrograde insertion or proximal/mid #, the pin is placed into the proximal segment from the fracture site cadaveric studies > retrograde pin placement for fractures of the distal part NOT be recommended, in either dogs or cats, due to the potential for damage

Answer 2

pin loosening breakage Complications usually occur as a direct result of fracture instability

Answer 3

apering shape of the humerus does not readily lend itself to interlocking nail fixation distal aspect of the bone,6 so there is often only room for placement of one locking device Suitable fractures for interlocking nail fixation are mid-diaphyseal, with sufficient bone on each side of the fracture | at least one bone diameter away from the fracture line

Answer 4

Complications fracture collapse, osteomyelitis, screw missing the nail hole, radial neuropraxia changes include the use of bolts rather than screw will change rate of these coplications

Answer 5

Type I Modified type I/II ESF tied into IM pin Usually placed on craniolateral surface IM pin can be placed first to aid bone alignment + prevent fragment rotation + resistance to bending | particularly where bone stock is limited proximal and distal

Answer 6

ESf + IM pin able to resist bending, shear, torsion, and compression at the fracture site. increase frame stability, and when the distal fragment is short, a centrally threaded, positive profile pin is placed as a full transcondylar pin may be advantageous to increase frame stiffness in large dogs

Answer 7

dogs aimed from craniodistal to the lateral epicondyle to exit the bone medially at a similar point halfway between the epicondyle and the articular surface cats similar, but the pin should be aimed from a position slightly cranial to the lateral epicondyle **2.0 mm or 1.6 mm** diameter pin

Answer 8

Craniolateral surface proximally Caudomedial surface distally

Answer 9

Medial - straighter epicondylar crest

Answer 10

plates positioned: - **craniolaterally** for fractures of the proximal and middle - **medially** for distal diaphyseal, supracondylar, and intracondylar fractures (less tissue dissection, straighter and better for cats vs need for careful dissection to preserve neurovascular) lateral surface of the distal half of the humerus: - marked curvature - close to the radial nerve and brachialis muscle - Penrose drain around the muscle and nerve - Curved plates designed for use on the distal aspect

Answer 11

A fracture which communicates with the supracondylar foramen but not with the articular surface Repair options: - Cross pins or Rush pinning (**immature**) - Unilateral or bilateral plate for comminuted (**adult**) - ESF - modified type I/II | require rigid stabilization because close proximity to elbow joint

Answer 12

- screws and plates do not interfere with elbow joint function - Distally (medial epicondyle), the plate can be placed medially, caudomedially, or caudally. - doouble plate (maximizing the number of screws that can be placed) - **locking plates**: > do not have to be contoured > allow angle-stable monocortical screw > diminishes the risk of screw insertion into the elbow joint > preserves local vascularity.

Answer 13

Fuse together: 8 to 12 weeks Fuse to metaphysis: 5.5 - 6m

Answer 14

Lateral (34 - 67%) (Salter Harris IV) Followed by T/Y (25.9 - 35%) Medial (6.9 - 11%) | In cats, olecranon fossa is absent, explain low incidence

Answer 15

20% study: evaluated the impact of growth plate damage after SH4 - showed no decrease in humeral length, even when the implants crossed the growth plate, so implant removal to allow for further growth is probably not indicated - growth plate closes at approximately 5 to 8 months of age

Answer 16

low-energy trauma such as jumping affects patients younger than 1 year of age (peak 4mths) Salter-Harris type IV fractures older dogs > preexisting humeral intracondylar fissure Ex pain and swelling that can be localized to the elbow joint epicondyles as the humerus subluxates from the ulnar notch important to take orthogonal radiographic views ensuring that the craniocauda

Answer 17

Anatomic reduction is usually achieved by open reduction > vs closed reduction with fluoroscopic guidance and minimally invasive surgery > transcondylar screw in lag fashion, with or without an antirotational pin, screw, or bone plate and screws > (self-compressing pins and a positional transcondylar screw)

Answer 18

Enter craniodistal to lateral epicondyle and exit at similar location on medial side Parallel to articular surface Perpendicular to fracture line | to minimize shear of the fracture fragments

Answer 19

Antirotation pin Supracondylar screw Lateral epicondylar plate

Answer 20

- minimizes the risk of implant-related growth plate damage - allows for accurate screw placement - fluoroscopic guidance > confirm that the screw does not cross the growth plate.

Answer 21

**normograde** - fracture reduced into anatomic reduction and secured with two reduction clamps - glide hole drilled from lateral to medial - Less soft tissue dissection and disruption of the joint capsule - exposure is limited for removing blood clot and fibrin from the fracture surface - intra-articular screw placement may occur **retrograde** - lateral part of condyle is rotated out > access to the fracture surface. - glide hole is then drilled from the fracture surface - drill bit to exit distocranial to the lateral epicondyle. - surgeon has control over screw placement - penetrate the articular surface is lessened. - difficult to place the screw at the appropriate transcondylar angle - Fracture reduction assessed by observing the fracture site on the lateral epicondylar crest - elbow should move freely, range of motion (particularly flexion) may be slightly restricted - Arthroscopic assessment of fracture reduction two pairs of pointed reduction forceps to prevent rotation when tightening the screw | sufficiently long > at least one thread protrudes from cortex

Answer 22

Kirschner wire were more likely to have major complications resulting in a poorer outcome than cases stabilized using a supracondylar screw or plate Osteoarthritis developed or progressed in all elbows Other studies have demonstrated a similar lack of correlation between accuracy of fracture reduction and outcome

Answer 23

usually caused by a fall, so a bending, rather than a shear force Chondrodystrophic breeds may be overrepresented.

Answer 24

osteotomy of the olecranon or tenotomy - the articular surface is first realigned using a transcondylar screw, then attached to the humeral diaphysis medial and lateral approach - medial part is stabilized to the diaphysis with a bone plate and screws - lateral part of the humeral condyle is stabilized with a screw in lag fashion and lateral bone plate and screws - medial the plate is positioned on the caudomedial aspect + screws angled in craniolateral direction - ensure that the screws do not penetrate the olecranon fossa or articular surface - lateral plate positioned on the caudal aspect

Answer 25

1. osteotomy of the tuber olecrani, good exposure but complications with repair 2. tenotomy of the tendon of the triceps brachii muscle, advantageous in immature animals because it avoids premature closure of the proximal ulnar growth plate. 3. separate lateral and medial approaches

Answer 26

inadequate stability is considered to be the key problem implant loosening breakage delayed union or nonunion.

Answer 27

23.5 - 25%

Answer 28

15 degree craniomedial caudolateral oblique

Answer 29

- Screw combined with transcondylar bone tunnels to allow vascular ingrowth - Autogenous cancellous bone graft - Fenestrated tubular screw 23% have implant fialure and loss of reduction

Answer 30

- ossification centers fail to fuse, and condyles remain separated by the fibrous band More recently, this theory was challenged by a study that reported the development of a fissure in Spaniel that 2 years previously had a completely normal elbow CT > support a previously noted hypothesis that stress fracturing may be involved - normal physiologic forces produce micro-movement, causes persistent thoracic limb lameness - predisposes to fracture - Spaniels appear to be the most predisposed breed, lab/pointer/GSD - often bilateral - pathogenesis of this condition is unclear: metabolic disease, a form of elbow dysplasia related to conformation, intense activity resulting in stress fracture - may be heritable with a recessive mode of inheritance - **Histology**: atrophic nonunion fracture with cancellous bone and osteosclerosis, no evidence of persistent cartilage

Answer 31

1. thoracic limb lameness (Pain on full extension of the elbow) 2. sustain an acute fracture of the humeral condyle (during fairly normal activity suspicious) contralateral distal humerus should also be assessed 3. diagnosed with incomplete ossification as an incidental finding on imaging

Answer 32

**rads** standard craniocaudal and flexed lateral views 15-degree craniomedial-to-caudolateral oblique projection fissure may extend only partway across the bone, making a radiographic diagnosis unlikely **Scintigraphy** bone activity will be increased. However, these changes are not specific **CT** more sensitive and specific method noninvasive examination complete hypoattenuation through the humeral condyle, articular surface > supratrochlear foramen, or partial fissure sclerosis surrounding fissure **Arthroscopic** may be used to confirm fissure in the articular cartilage not seen in all cases

Answer 33

**Conservative** high rates of fracture 3 of 7 (43%) with a partial radiolucent line and 1 of 12 (8%) with a complete radiolucent line fractured 11 days to 18 months after diagnosis **prophylactic surgical repair** as large a transcondylar screw as possible to reduce fatigue failure 4.5 mm cortical screw is suitable Controversy: positional vs lag fashion Medial-to-lateral drilling for transcondylar screw placement carries a higher risk of inadvertently penetrating the joint more guarded prognosis > difficulties in achieving healing of the fissure line. The development of a nonunion 23% had implant failure and loss of reduction. Infection seroma formation

Answer 34

- fractures of the humeral diaphysis is good - articular surface of the condyle is more guarded, residual lameness + reduced ROM common - posttraumatic osteoarthritis - Y fracture: veterinary surgeon follow-up 41% had an excellent outcome, 52% were considered good, and 10% were considered fair - IOHC: prognosis is even more guarded, with nonunion and implant failure commonly occurring.

Answer 35

Controlled clinical study. Animals: Dogs with HIF (14 dogs, 21 elbows) and dogs without HIF (20 dogs) cartilage lesion on the caudal humeral condyle of dogs with HIF. The lesion was found in all dogs with HIF but in no dogs without HIF. Clinical significance: Humero-anconeal incongruity and an associated cartilage lesion appear to be present in dogs with HIF. We propose that this lesion may be associated with humero-anconeal incongruity. The modification of the previously reported arthroscope portal to a caudo-medial: - allowed the inspection of all major intra-articular structures of the medial elbow joint compartment and partially of the lateral - allowed the caudal aspect of the humeral condyle to be inspected

Answer 36

Retrospective. 74. medial epicondylar fissure fracture during placement of 4.5mm shaft screw medially - rate: 11.4%, related to larger relative screw size (screw to height of condyle) - screw loosening most common complication (11.2%) - not associated with fissure fractures - complication rate: 22.4%, major 12.5%, minor 9.9% screws < 41% height of the condyle is recommended to avoid MEFF. care with torque applied. MEFF appears to have a low clinical significance

Answer 37

41. retro. epicondylar plate fixation + TCS for humeral condylar fractures in Frenchies - major complications 4/45 (8.9%) > reached union following revision surgery - 41/45 → radiographic union without further intervention - excellent long-term outcome in 26/26 with follow-up, no impact of crossing physis (absence of obvious condylar deformity evident) Chondrodystrophic at risk > eccentrically positioned capitulum and a relatively small lateral epicondylar crest contralateral HIF (15%) >2 subsequently developed #

Answer 38

Retrospective. 44 frenchies Lateral humeral condylar fractures (63.6%) contralateral HIF in 58.1% - age not correlated - complications: transcondylar screw + K-wire 7.62x more likely to → major complication - transcondylar screw migration in 100% of cases with TCS+K-wire fixation Ossification in the humeral condyle did not appear to occur in the previously described age range of other breeds. IOHC may have a part to play in prevalence of HCF seen in French bulldogs.

Answer 39

evaluate the accuracy of an aiming device on placement of humeral transcondylar screws 68 cadavers risk of joint involvement was 8 times greater in aiming device groups, though not significant (p = .0575). aiming device used > joint involvement (10%), compared to (1.5%) fluoroscopic Significant complications included increased drill attempts in fluoroscopic groups (p = .0237). The aiming device Results were similar to fluoroscopic-guided method.

Answer 40

retrospective Eighty dogs with 85 HCF were identified: 13 (15.3%) HCF were medial (bilateral in two dogs) and 72 (84.7%) were lateral (bilateral in three dogs). French Bulldogs (n = 19/80; 23.8%) were most commonly affected ORIF A transcondylar screw (TS) combined with a supracondylar (SC) K-wire (67/80; 83.8%) Considering all fracture fixation methods, complications (26/80; 32.5%) were classed as minor in 10 (12.5%), major in 14 (17.5%) and catastrophic in two (2.5%) Long-term outcome was excellent in 68.6% (24/35 HCF)

Answer 41

cannulated drill bits aremuch less efficient at drilling dense bone compared with a sharp drill bit, so they also have the potential to cause bone necrosis | temperatures above 55°C causing bone necrosis

Answer 42

Retrospective. 136. Humeral Condylar Fractures in French Bulldogs lateral 69.8% Complications (22%), 10 were major, and 20 minor. Fixation method did not impact complication rate kwire, plate, leap Comminution increased the risk of complication 9.77% HIF Prophylactic placement of a humeral transcondylar screw carries a high published rate of complication **Hattersley 2011 > case series 57, overall complication rate was 59.5%. Seroma (25) and SSI (24) most commonly. 2 screw failure. Lag possibly reduced risk** A recent case report > spontaneous resolution of HIF can occur in this breed.

Answer 43

observational radiographic retrospective study, particular attention should be taken when evaluating cases of humeral condylar fractures for a potential associated fractured medial coronoid process, even more so in comminuted fractures

Answer 44

Prospective, randomly assigned medial-lateral or lateral-medial TCS placement. 52. Shorter follow up period. - overall complications 41.1%, lateral 62%, medial 19% - 7/7% major complication rate - lower AMI implants associated with higher risk of major complication > place an implant with an AMI/bodyweight greater than 0.3 > > recent recommendations < 41% condyle size - seroma and SSI – proposed due to pressure on lateral screw head in recumbency. Overall rate 23.3, M>L 11% >> headless screws that are buried, reduce SSI? - 46.6% concurrent medial coronoid disease but majority of dogs responded to TCS alone implant failure of transcondylar screws for HIFs have been reported 4 years following surgery

Answer 45

Cadaveric lateral condylar fracture model: Ex vivo comparison of pins and plates with a novel composite (AdhFix) yield load was significantly higher for AdhFix compared to the pin No statistical significance was seen with plate group a technique that circumvents plate contouring | high energy visible light-cured fixator plate

Answer 46

Retrospective. 35. bioblique proximal ulnar osteotomy with elevation of interosseous ligament and K-wire placement + rhBMP for dogs >8mth - partial/complete healing in 80.3% (objective by measure HU units) - HIF due to caudal contact between humerus and anconeal process - axial and rotational loading of tip of anconeal process of caudo-proximal aspect of medial aspect of humeral condyle during weightbearing prevents fusion of humeral condylar ossification centers in young dogs → stress fracture in old dogs - major complications in 5/35 (14.3%) - lack of fissure healing → fracture - adjunct TCS recommended in dogs >8yo - prolonged exercise restriction post-op – up to 6 months on lead > slower healing in older dogs: sclerosis present on either side of the fissure of older dogs can further act as an important barrier to angiogenesis across the fissure. risk of delayed or nonunion, 31.1% in a recent manuscript analyzing PUO in dogs **letter to editor**: overall complication rate to 13/51 (25%). More recent studies trend towards lower complication rates. Walton et al., reported a major complication rate of 2/34 (6%) humeri treated with the humeral intracondylar repair system with no conservatively managed control group, this causation effect is not proven and the conclusion is scientifically unsound.

Answer 47

Ex vivo. 4.5 mm transcondylar positional vs cortical lag screws. model does not mimic the clinical > specimens were not cycled positional screw → increased stiffness, yield load and max load vs lag screw for > suspected that either screw for prophylactic treatment of HIF, may be an appropriate cons lag screw: may deform and weaken the medial and lateral supracondylar regions. less cis cortex purchase and compression may expose the screw to additional bending forces

Answer 48

Retrospective. 62. complication rate for fluoro-guided TCS = 45%, 15% required revision - risk factors for complications: earlier in the case series, increasing bWt - increased sx time protective – proposed slower drilling speed - all cases had improvement in lameness with TCS alone, 32% residual mild-mod lameness (due to concurrent MCPD?) Complications associated with transcondylar screw placement for HIF are common and range from 15 to 69% | accuracy not assessed

Answer 49

Retrospective case series. Animals: Twenty-five client-owned dogs with HIF 4.5-mm transcondylar screw Entry and exit points were planned at 0.3 Humeral condylar diameter cranial and 0.2 HCD distal to the medial epicondyle and 0.3 HCD cranial and 0.3 HCD distal to the lateral epicondyle Humeral transcondylar screws placed with the technique tested here were entirely within the humeral condyle in 33 out of 34 elbows deviation from the optimal drill line during the placement of 21 of 34 screws. In one of 34 elbows, this deviation was sufficient to result in penetration of the screw into the elbow joint. > seen during an arthroscopy performed immediately after screw is potentially exposed to many cycles of loading. Bending loads are concentrated on the part of the screw that crosses the fissure, these stress concentrating phenomena can be sufficient to lead to fatigue failure of the transcondylar screw.19,23 This can lead to recurrence of lameness or HCF This study did not include a control group with placement of a screw without an aiming device

Answer 50

Retrospective. humeral intracondylar repair system. 1/34 major surgical and 1/34 major medical complication for HIF = 6% major (low rate of SSI) 2/14 major surgical and 1/14 major medical fractures (implant losening, infection) drill bit creates a 5.9 mm diameter void at the fissure > packed with graft we report at least partial healing in all cases with CT follow-up, with the fissure accounting for <50% of the cross-sectional area of the condyle in 15 of 17 cases. Previous studies: post-op infection 21-30% (not all receieve post-op abs)

Answer 51

Retrospective case series. Animals: Twenty-eight client-owned dogs bilateral LCP and TCS for bicondylar fracture - 82.7% anatomical reduction, 6.8% major complications - 96.4% good-excellent outcome, 64% free of lameness at 6wk Long-term studies with objective outcome measures needed

Answer 52

French Bulldogs (OR 5.86) and English springer spaniels (OR 5.66) overrepresented for humeral condylar fracture - median age 4mth (2-10), 70% lateral, 9% medial, 21% bicondylar

Answer 53

French bulldogs are predisposed to HCF, including medial HCF. Epicondylar plate fixation is recommended over other epicondylar fixation methods to reduce complications There was norandomization of repair technique or prospective measurement of outcome indices Implant-related complications were significantly lower with plate constructs than with epicondylar screw(s) ± epicondylar K-wire(s) or with epicondylar K-wire(s) alone, which is in line with a previous study on lateral condylar fractures the pathogenesis of HCF in French bulldogs remains unknown. Among the fractures that had contralateral limb imaging, only 16 had a HIF, and none were French bulldogs; Sixty-nine percent of dogs had reduced elbow ROM at the first follow-up, which decreased to 33% at last radiographic follow-up outcome was excellent in 87% of dogs according to the long-term CBPI and questionnaire results. Previous literature has reported fair and poor limb function in 57% of dogs1 as well as 36% mild occasional lameness and 18% moderate to severe lameness.

Answer 54

Retrospective consecutive case series. Animals: 11 Client-owned dogs with HIF treated with a 5-mm transcondylar use of 3D printed patient-specific drill guides for HIF - some cranial translation in all cases, angulation of screws still occurred. no intra-articular. - overdrill of pilot hole invasive to fit guide on

Answer 55

outcome in 3 cases No complica tions were recorded in any of the cases, and lameness had completely resolved by the final recheck This study provides evidence that minimally invasive plate osteosynthesis represents an alternative to open reduction and internal fixation in the treatment of comminuted humeral T-Y fractures.

Answer 56

retrospective review, 18 dogs of locking screws may have been influential in minimizing primary loss of reduction, potentially maintaining the initial fragment reduction. In the present study, short-term outcome was excellent or adequate inmost cases aswas the long-term outcome.No dogs required additional surgery; however, the implant failure dog could have been a potential candidate for revision, although the pre-existing circumstances would remain a concern. The short-term outcome compared favourably with previous reports.1–3,6 Overall, the use of LCP, taking advantage of hybrid fixation and monocortical locking screws distally, gave good clinical outcomes and accurate articular alignment.

Answer 57

Retrospective. 35. SSI rate between medial-lateral vs lateral-medial directed TCS not different - overall complication rate 47.8%, SSI 23.9%, other mostly seroma - bWt and GA time → increased risk - administration of oral antibiotic medications after humeral intracondylar fissure surgery did not appear to influence the SSI incidence

Answer 58

design of canine humeral anatomic plating system (CHAPS) based on CT- morphometric data

Answer 59

patellar fracture and dental anomaly syndrome (PADS). Conclusion: Evidence of progression of HIF to fracture in a cat with PADS has implications for management of elbow-related lameness in this species. In this report, we seek to alert practitioners to the potential for HIF to be seen in cats

Answer 60

majority of the fractures were diaphyseal (71%), with only 10% condylar 16 (28%) plate–rod 31 (54%) external skeletal fixation (more comminuted fractures??) 10 (18%) plating and screws Open diaphyseal fractures were associated with more minor complications (P = 0.048). There was a significant difference between fixation groups in terms of overall complication rate between groups (P = 0.012). There was no significant difference between fixation groups in time to radiographic union (P = 0.145) or time to acceptable function (P = 0.306). Conclusions and relevance All three fixation systems were successful There was a significantly higher overall complication rate with ESF; however, the clinical impact of these is likely low.

Answer 61

retrospective 61 dogs Intraoperative contouring of the plate was required for one dog overall there were 14 minor, 8 major, and 2 catastrophic complications (35%) partial or complete osseous continuity of the condylar part of the fracture 32/53 HCF and lateral epicondylar part of the fracture in 53/53 HCF 20/28 dogs with lateral # and 5/13 dogs with T/Y# were not lame direct comparison of the LEAP with other epicondylar fixation methods was not performed

Answer 62

Eighty-nine dogs with HCF were included and 36/89 were diagnosed with HIF. 40% of French Bulldogs with HCF had a contralateral HIF. HIF as a cause of HCF should be considered in the French Bulldog,

Answer 63

Follow-up CT demonstrated resolution of the humeral intracondylar fissure in 11 (91.7%) of 12 cases. Contralateral humeral intracondylar fissures are common in skeletally immature French bulldogs sustaining humeral condylar fractures and the majority of these fissures tend to fuse within the follow-up period. Due to the potential for breed variation in ossification of the humeral condyle, follow-up CT may be warranted in skeletally immature French bulldogs before considering prophylactic transcondylar screw placement age of follow up CT 4-7mths. a prospective study evaluating serial CT scans at regular intervals until the dogs reach skeletal maturity would be necessary.

Ch 51 fractures of the humerus Flashcards

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