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TROCHLEAR FRACTURE ADULT

Introduction

Fracture Nomenclature for Trochlear fractures

Hand Surgery Resource’s Diagnostic Guides describe fractures by the anatomical name of the fractured bone and then characterize the fracture by the Acronym:

In addition, anatomically named fractures are often also identified by specific eponyms or other special features. For the trochlear fracture, the historical and specifically named fractures include no common eponyms.

Fractures of the humeral trochlea are intra-articular coronal shear fractures that rarely occur in isolation. The most common mechanisms of injury for trochlear fractures are falls on an outstretched hand—with the elbow extended—and falls producing an axial force upon the elbow with the elbow in some degree of flexion. Associated bone and soft tissue injuries are common and may include capitellar fractures, ligamentous injuries, ipsilateral fractures, and dislocations. Due to their low incidence, trochlear fractures are often overlooked at the initial evaluation, which can complicate long-term treatment plans. Although closed reduction may be considered for trochlear fractures that are minimally displaced or displaced without significant comminution, surgical intervention is typically preferred by most treating physicians.1-4

Definitions

  • A trochlear fracture is a disruption of the mechanical integrity of the trochlea.
  • A trochlear fracture produces a discontinuity in the trochlea contours that can be complete or incomplete.
  • A trochlear fracture is caused by a direct force that exceeds the breaking point of the bone.

Hand Surgery Resource’s Fracture Description and Characterization Acronym

SPORADIC

S – Stability; P – Pattern; O – Open; R – Rotation; A – Angulation; D – Displacement; I – Intra-articular; C – Closed

S - Stability (stable or unstable)

  • Universally accepted definitions of clinical fracture stability is not well defined in the literature.5-7
  • Stable: fracture fragment pattern is generally nondisplaced or minimally displaced. It does not require reduction, and the fracture fragments’ alignment is maintained by with simple splinting or casting. However, most definitions define a stable fracture as one that will maintain anatomical alignment after a simple closed reduction and splinting. Some authors add that stable fractures remain aligned, even when adjacent joints are put to a partial range of motion (ROM).
  • Unstable: will not remain anatomically or nearly anatomically aligned after a successful closed reduction and immobilization. Typically unstable trochlear fractures have significant deformity with comminution, displacement, angulation, and/or shortening.

P - Pattern2

  • Type 1: shear fracture involving most of the capitellum and little or none of the trochlea
  • Type 2: variable amount of articular cartilage of the capitellum with minimal attached subchondral bone
  • Type 3: comminuted or compression fracture of the capitellum
  • Type 4: shear coronal fracture of the distal humerus involving the capitellum and most of the trochlea

O - Open

  • Open: a wound connects the external environment to the fracture site. The wound provides a pathway for bacteria to reach and infect the fracture site. As a result, there is always a risk for chronic osteomyelitis. Therefore, open fractures of the trochlea require antibiotics with surgical irrigation and wound debridement.5,8,9

R - Rotation

  • Trochlear fracture deformity can be caused by proximal rotation of the fracture fragment in relation to the distal fracture fragment.
  • Degree of malrotation of the fracture fragments can be used to describe the fracture deformity.
  • Fracture fragments in trochlear fractures are typically rotated internally.3

A - Angulation (fracture fragments in relationship to one another)

  • Angulation is measured in degrees after identifying the direction of the apex of the angulation.
  • Straight: no angulatory deformity
  • Angulated: bent at the fracture site

D - Displacement (Contour)

  • Displaced: disrupted cortical contours
  • Nondisplaced: ≥1 fracture lines defining one or several fracture fragments; however, the external cortical contours are not significantly disrupted
  • Fracture fragments in trochlear fractures are typically displaced proximally.3

I - Intra-articular involvement

  • Intra-articular fractures are those that enter a joint with ≥1 of their fracture lines.
  • All trochlear fractures are considered intra-articular fractures.3
  • Isolated trochlear fractures can have fragment involvement with the ulnohumeral joint, while concomitant fractures with the capitellum can also involve the radiocapitellar joint.
  • If a fracture line enters a joint but does not displace the articular surface of the joint, then it is unlikely that this fracture will predispose to post-traumatic osteoarthritis. If the articular surface is separated or there is a step-off in the articular surface, then the congruity of the joint will be compromised, and the risk of post-traumatic osteoarthritis increases significantly.

C - Closed

  • Closed: no associated wounds; the external environment has no connection to the fracture site or any of the fracture fragments.4-6

Related Anatomy3,10

  • The elbow is a hinge-type synovial joint comprised of the radius, ulna, and humerus, and formed by three articulations: the ulnohumeral joint, radiocapitellar joint, and proximal radioulnar joint.
  • The ulnohumeral joint is a hinge joint in which the trochlear notch (or semilunar notch) of the ulna articulates with the trochlea of the humerus. It allows for elbow flexion and extension.
    • The trochlea is the medial portion of the articular surface of the distal humerus, which is contained between the lateral and medial columns of the elbow and is primarily covered with articular cartilage. It has medial and lateral ridges with an intervening trochlear groove.
  • The radiocapitellar joint is the articulation of the radial head with the capitellum of the humerus.
    • The capitellum is the lateral column of the distal humerus. It is covered with articular cartilage on its anterior and inferior sides, but not its posterior side.
  • The key ligaments of the elbow include the lateral collateral ligament (LCL, which extends from the lateral epicondyle and blends with the annular ligament of the radius), the medial collateral ligament (MCL, which originates from the medial epicondyle and attaches to the coronoid process and olecranon of the ulna), and the annular ligament which encircles and stabilizes the radial head within the radial notch.
  • The key tendons of the elbow include the tendons associated with the biceps, triceps, and extensor carpi radialis longus (ECRL) muscles as well as the common extensor tendon (the shared origin of the extensor carpi radialis brevis (ECRB), extensor digitorum communis (EDC), extensor digiti minimi (EDM) and extensor carpi ulnaris (ECU)), and the common flexor tendon (the shared origin of the pronator teres, flexor carpi radialis (FCR), palmaris longus, flexor digitorum superficialis (FDS), and flexor carpi ulnaris (FCU)).

Incidence

  • Coronal fractures of the distal humerus involving the capitellum and trochlea are extremely rare, accounting only for 1% of all elbow fractures and 3–6% of all distal humeral fractures.11
    • Isolated trochlear fractures are even less common than isolated capitellar fractures.3
  • LCL injuries or radial head fractures have been documented in ~60% of patients with coronal shear fractures of the distal humerus, including trochlear fractures.1

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ICD-10 Codes

  • TROCHLEAR FRACTURE - ADULT

    Diagnostic Guide Name

    TROCHLEAR FRACTURE - ADULT

    ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    TROCHLEAR FRACTURE - ADULT    
    - DISPLACED S42.462_S42.461_ 
    - NONDISPLACED S42.465_S42.464_ 

    Instructions (ICD 10 CM 2020, U.S. Version)

    THE APPROPRIATE SEVENTH CHARACTER IS TO BE ADDED TO EACH CODE FROM CATEGORY S42
     Closed FracturesOpen Type I or II or OtherOpen Type IIIA, IIIB, or IIIC
    Initial EncounterABC
    Subsequent Routine HealingDEF
    Subsequent Delayed HealingGHJ
    Subsequent NonunionKMN
    Subsequent MalunionPQR
    SequelaSSS

    ICD-10 Reference

    Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams
TROCHLEAR FRACTURE ADULT
  • Trochlear Fracture (arrows) as part of a distal humerus fracture
    Trochlear Fracture (arrows) as part of a distal humerus fracture
  • Trochlear Fracture (arrows) as part of a distal humerus fracture
    Trochlear Fracture (arrows) as part of a distal humerus fracture
Symptoms
History of trauma
Fracture pain
Fracture deformity, swelling, ecchymosis and/or tenderness
Abrasion
Typical History

A typical patient is a 35-year-old woman who slipped on a loose rug in the hallway while carrying a pile of laundry. She landed on her right elbow, which was partially flexed, on the hardwood floor. The impact of the fall resulted in a fracture of the humeral trochlea and an LCL tear in her right arm. Immediately after the injury, the woman experienced moderate-to-severe pain, swelling, tenderness, and restricted range of motion in her elbow.

Positive Tests, Exams or Signs
Work-up Options
Images (X-Ray, MRI, etc.)
Trochlear Fracture
  • Trochlear Fracture (arrows), AP X-ray, as part of a distal humerus fracture
    Trochlear Fracture (arrows), AP X-ray, as part of a distal humerus fracture
  • Trochlear Fracture (arrows), CT Scan, as part of a distal humerus fracture
    Trochlear Fracture (arrows), CT Scan, as part of a distal humerus fracture
  • Trochlear Fracture (arrows), Lateral X-ray, as part of a distal humerus fracture
    Trochlear Fracture (arrows), Lateral X-ray, as part of a distal humerus fracture
Treatment Options
Treatment Goals
  • When treating closed trochlear fractures, the treating surgeon has 4 basic goals:5,9
    1. An elbow with a normal appearance. The X-ray may not need to be perfect, but the elbow should have no obvious deformity (ie, the elbow looks normal!)
    2. Avoid elbow stiffness by maintaining a normal functional ROM (ie, the elbow works!)
    3. The elbow is not painful (ie, the elbow does not hurt!)
    4. Congruent joint surface with none-to-minimal joint surface irregularities (ie, the elbow does not develop early post-traumatic arthritis!)
  • One additional goal is mandatory for open fractures:
    • Fracture care should minimize the risk for infection and osteomyelitis.
Conservative
  • Trochlear fractures with articular displacement <2 mm—which are rare—and displaced fractures without significant posterior comminution can potentially be treated conservatively with closed reduction and immobilization; however, outcomes are unpredictable in these cases, and thus most trochlear fractures are currently treated surgically.1,4,10,12
Operative
  • Surgical treatment of trochlear fractures must always be an individualized therapeutic decision. However, surgical trochlear fracture care is most frequently recommended when:
    1. Closed reduction fails or the simple splint or cast immobilization does not maintain the reduction. For these irreducible or unstable fractures, operative treatment is recommended to achieve the 4 treatment goals of fracture care.
    2. There is a significantly displaced trochlear fracture involving the ulnohumeral joint or radiocapitellar joint.
    3. Open trochlear fractures. These injuries require surgical care in the form of irrigation and debridement to prevent chronic infection.
  • Open reduction and internal fixation (ORIF)
    • Generally regarded as the preferred treatment for most displaced trochlear fractures.1
    • Can effectively restore the congruity of articular surfaces and allow for early elbow mobilization.11
  • Other surgical options1,11
    • Arthroplasty
      • For lower-demand and/or elderly patients or when stable internal fixation cannot be completed
    • Fragment excision
    • Arthroscopic-assisted reduction and internal fixation
  • Fixation methods1
    • Fine-threaded K-wires
    • Biodegradable pins
    • Headless compression screws
    • Small fragment cancellous screws
    • Plates

Post-treatment Management

  • The care and precautions related to immobilization devices for the trochlear fracture must be carefully reviewed with the patient. Patients should be educated regarding care and precautions. Patients should know that pain, especially increasing pain, numbness, tingling, skin irritation, splint loosening, or excessive tightness are red flags and should be reported to the surgeon or his team.
  • Pain should be managed with properly fitting splints and casts, reassurance, elevation, ice in the initial post-fracture period, and mild pain medications. Patients should be encouraged to discontinue pain medication as soon as possible. Opioid use should be kept to a minimum.
  • Joints that are splinted for closed stable fractures are usually immobilized.
  • Fractures that require internal fixation can typically be mobilized after 4-6 weeks.
  • After surgery, the elbow is splinted in a stable position for 2 weeks, after which the patient can begin moving the joint. The integrity of the LCL and MCL should be incorporated into a ligament-specific rehabilitation protocol, and radiographs are used in the first 3 weeks to ensure joint congruency. Unrestricted range of motion can begin at 6 weeks, and then progressive strengthening at 8–10 weeks after surgery if there is evidence of fracture healing.1
  • A thorough physical examination of patients is imperative to detect any associated injuries—such as an elbow dislocation, LCL or MCL injury, or radial head fracture.1 With all elbow fractures the neurologic exam should include assessment of the median, radial, and ulnar nerves, as well as their more distal branches (eg, anterior and posterior interosseous nerves and cutaneous branches).10
Complications
  • Elbow stiffness13
  • Post-traumatic arthritis
  • Nonunion
  • Heterotopic bone formation
  • Avascular necrosis
  • Neurologic complications
  • Fixation failure
  • Post-traumatic osteoarthritis
  • Osteomyelitis
Outcomes
  • The general use of ORIF for complex distal humerus fractures is associated with satisfactory or better outcomes in 71–86% of patients. Most patients can expect overall arc of motion of approximately 100° and about a 75% return of strength after recovering from surgery.10
    • However, although ORIF is the preferred surgical treatment for displaced trochlear fractures and has been the most studied procedure, evidence to support this approach is limited to small, non-comparative case series.1
  • Studies comparing the outcomes of conservative treatment to surgery for trochlear fractures are lacking.4
Key Educational Points
  • Evidence-based treatment recommendations for trochlear fractures do not exist and establishing a definitive management plan is challenging because the injury pattern is uncommon, the clinical research available is limited to case series, and most research features a range of outcome measures, which complicates data comparisons. Thus, treatment decisions should generally be based on the fracture characteristics and presence of concomitant injury.1
  • Healthcare providers must investigate for concomitant injury during the diagnosis of trochlear fractures, such as capitellar fractures, LCL or MCL lesions, or ipsilateral fractures (eg, radial head fractures or epicondylar humeral fractures), which can have significant implications on treatment decisions.11
  • Providers should also be keen to recognize and properly address comminuted fractures with associated bone defects, as small fragment fixation may be achieved with countersunk fine-threaded K-wires in the presence of extensive comminution. Nonthreaded K-wires should be avoided in these cases due to the risk for migration.1
  • Although closed reduction and immobilization were once used frequently to treat isolated capitellar and trochlear fractures, increased understanding of the complexity of these injuries has ushered in a preference shift toward surgical intervention—particularly ORIF—in management strategies.13
  • Anteroposterior (AP), lateral, oblique, and radiocapitellar X-ray views of the elbow are necessary.1 Since plain radiography cannot identify subtle fracture planes and underestimates the extent of comminution, a CT scan may be necessary.1
References

Cited Articles

  1. Carroll, MJ, Athwal, GS, King, GJ, et al. Capitellar and Trochlear Fractures. Hand Clin 2015;31(4):615-30. PMID: 26498550
  2. Dubberley, JH, Faber, KJ, Macdermid, JC, et al. Outcome after open reduction and internal fixation of capitellar and trochlear fractures. J Bone Joint Surg Am 2006;88(1):46-54. PMID: 16391249
  3. Mehdian, H and McKee, MD. Fractures of capitellum and trochlea. Orthop Clin North Am 2000;31(1):115-27. PMID: 10629337
  4. Ashwood, N, Verma, M, Hamlet, M, et al. Transarticular shear fractures of the distal humerus. J Shoulder Elbow Surg 2010;19(1):46-52. PMID: 19884023
  5. Cheah, AE and Yao, J. Hand Fractures: Indications, the Tried and True and New Innovations. J Hand Surg Am 2016;41(6):712-22. PMID: 27113910
  6. Nesbitt, KS, Failla, JM and Les, C. Assessment of instability factors in adult distal radius fractures. J Hand Surg Am 2004;29(6):1128-38. PMID: 15576227
  7. Walenkamp, MM, Vos, LM, Strackee, SD, et al. The Unstable Distal Radius Fracture-How Do We Define It? A Systematic Review. J Wrist Surg 2015;4(4):307-16. PMID: 26649263
  8. Ketonis, C, Dwyer, J and Ilyas, AM. Timing of Debridement and Infection Rates in Open Fractures of the Hand: A Systematic Review. Hand (N Y) 2017;12(2):119-126. PMID: 28344521
  9. Meals, C and Meals, R. Hand fractures: a review of current treatment strategies. J Hand Surg Am 2013;38(5):1021-31. PMID: 23618458
  10. Miller, AN and Beingessner, DM. Intra-articular distal humerus fractures. Orthop Clin North Am 2013;44(1):35-45. PMID: 23174324
  11. He, SK, Xu, L, Guo, JH, et al. The impact of associated injuries and fracture classifications on the treatment of capitellum and trochlea fractures: A systematic review and meta-analysis. Int J Surg 2018;54(Pt A):37-47. PMID: 29684669
  12. McKee, MD, Jupiter, JB and Bamberger, HB. Coronal shear fractures of the distal end of the humerus. J Bone Joint Surg Am 1996;78(1):49-54. PMID: 8550679
  13. Ruchelsman, DE, Tejwani, NC, Kwon, YW, et al. Coronal plane partial articular fractures of the distal humerus: current concepts in management. J Am Acad Orthop Surg 2008;16(12):716-28. PMID: 19056920
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