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CAPITELLAR FRACTURE ADULT

Introduction

Fracture Nomenclature for Capitellar 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 capitellar fracture, the historical and specifically named fractures include no common eponyms.

Fractures of the capitellum are coronal shear fractures of the distal humerus that rarely occur in isolation. The most common mechanisms of injury are falls on an outstretched hand (FOOSH) and falls that produce direct axial compression of the elbow while in a semi-flexed position. Associated bone and soft tissue injuries are extremely common and may include trochlear fractures, ligamentous injuries, ipsilateral fractures, and dislocations. Due to their low incidence, capitellar fractures are often overlooked during the initial evaluation, which can adversely affect long-term outcomes. Although conservative treatment with closed reduction and immobilization may be considered for minimally displaced capitellar fractures and displaced fractures without significant comminution, the general preference of most treating physicians is now surgical intervention.1-5

Definitions

  • A capitellar fracture is a disruption of the mechanical integrity of the capitellum.
  • A capitellar fracture produces a discontinuity in the capitellum contours that can be complete or incomplete.
  • A capitellar 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.6-8
  • 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).  A stable capitellar fracture does not displace during active elbow motion.
  • Unstable: will not remain anatomically or nearly anatomically aligned after a successful closed reduction and immobilization. Typically, unstable capitellar 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 capitellum require antibiotics with surgical irrigation and wound debridement.6,9,10

R - Rotation

  • Capitellar fracture deformity can be caused by rotation of the proximal 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 capitellar 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 capitellar 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 capitellar fractures are considered intra-articular fractures.3
  • Isolated capitellar fractures can have fragment involvement with the radiocapitellar joint, while concomitant fractures with the trochlea can also involve the ulnohumeral 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 Anatomy3,4,11,12

  • The elbow is a complex 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. This joint 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. It is essential to elbow longitudinal and valgus stability and has an integral relationship with the lateral collateral ligament (LCL).
    • The capitellum is a smooth, round, hemispheric structure that represents a portion of a forward-and downward-projecting sphere and which forms the anterior and inferior articular surface of the distal humerus. It is covered with articular cartilage on its anterior and inferior sides, but not its posterior side.
    • The elbow’s axis of flexion-extension and the axis of forearm rotation both pass through the capitellum, which enables effective reach by allowing the hand to function at different distances from the body.
  • 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 the 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

  • Capitellar fractures account for about 0.5–1% of all elbow fractures and about 6% of distal humerus fractures.3,12
  • Capitellar fractures are more likely to occur in women than men, which may be related to cubitus valgus, cubitus recurvatum, or osteoporosis.12
  • LCL injuries or radial head fractures have been documented in ~60% of patients following all coronal shear fractures of the distal humerus, which includes capitellar fractures.1

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ICD-10 Codes

  • CAPITELLAR FRACTURE - ADULT

    Diagnostic Guide Name

    CAPITELLAR FRACTURE - ADULT

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

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    CAPITELLAR FRACTURE - ADULT    
    CAPITELLUM (LATERAL CONDYLE OF HUMERUS)    
    - DISPLACED S42.452_S42.451_ 
    - NONDISPLACED S42.455_S42.454_ 

    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
Capitellar Fracture Adult
  • Left adult capitellar and later epicondylar fracture with arrows at fracture lines and at positive anterior fat pad sign.
    Left adult capitellar and later epicondylar fracture with arrows at fracture lines and at positive anterior fat pad sign.
Symptoms
History of upper extremity (elbow) trauma
Elbow pain
Elbow deformity and/or swelling
Elbow ecchymosis and/or skin abrasions
Typical History

A typical patient is a 42-year-old healthy woman who was jogging on a trail when she failed to notice a protruding tree root and tripped. She landed on her outstretched left hand, which produced a substantial axial force that was transmitted through the radial head to the distal humerus, fracturing both the trochlea and the capitellum. Upon recovering from the fall, the woman’s elbow became swollen, tender, and painful, and she had difficulty extending and flexing the joint. Later that day, she presented to the emergency department where elbow X-rays showed a displaced capitellar fracture.  The fracture was subsequently treated with open reduction and internal fixation.

Positive Tests, Exams or Signs
Work-up Options
Images (X-Ray, MRI, etc.)
Capitellar Fracture X-rays and CT Scan
  • Left adult capitellar and later epicondylar fracture with arrows at fracture lines and at positive anterior fat pad sign.
    Left adult capitellar and later epicondylar fracture with arrows at fracture lines and at positive anterior fat pad sign.
  • Left adult capitellar CT with arrows at fracture line.
    Left adult capitellar CT with arrows at fracture line.
Treatment Options
Treatment Goals
  • When treating closed capitellar fractures, the treating surgeon has 4 basic goals:6,10
    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 (i.e., the elbow works!)
    3. The elbow is not painful (i.e., the elbow does not hurt!)
    4. Congruent joint surface with none-to-minimal joint surface irregularities (i.e., There is no elbow crepitus with motion and the elbow does not develop early post-traumatic arthritis!)
  • One additional goal is mandatory for open fractures:
    1. Fracture care should minimize the risk for infection and osteomyelitis.
Conservative
  • Capitellar 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 posterior splint immobilization. However, outcomes are often unpredictable in these cases, and for this reason, most capitellar fractures are currently treated surgically.1,4,11,13
  • Other potential indications for conservative treatment include patients with a neurologic impairment, severe osteopenia/bone deficiency, soft tissue issues (eg, infection or skin loss), and patients who cannot tolerate or may not benefit from surgery.11
Operative
  • Surgical treatment of capitellar fractures must always be an individualized therapeutic decision. However, capitellar 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 radiocapitellar joint or ulnohumeral joint.
    3. Open capitellar 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 capitellar fractures displaced >2 mm.1
    • ORIF can effectively restore the congruity of articular surfaces and allow for early elbow mobilization.14
    • ORIF with lateral column approach
      • Indicated for isolated capitellar fractures and some Type 4 fractures.
    • ORIF with posterior approach (with or without olecranon osteotomy)
      • ORIF is also indicated for capitellar fractures with associated fractures to the distal humerus/olecranon and/or medial surface of the elbow.
  • Other surgical options1,14
    • Total elbow arthroplasty
      • For lower-demand and/or elderly patients or when stable internal fixation cannot be completed.
    • Arthroscopic-assisted reduction and internal fixation (AARIF)
      • Indicated for isolated Type 1 fractures with good bone stock.
    • Fragment excision
      • Indicated for Type 2 and Type 3 fractures displaced >2 mm.
    • Capitellar excision remains a treatment option for fractures that cannot be internally fixed
    • Prosthetic replacement has been an option in the past but is currently unavailable
  • Fixation hardware options1
    • Fine-threaded K-wires
    • Biodegradable pins
    • Small fragment cancellous screws
    • Cannulated headless compression screws
      • Recommended for fractures with only a thin shell of subchondral bone.1
    • Cannulated threaded screws (partially or fully threaded)
      • Recommended for large capitellum fractures with sufficient subchondral bone.1
Treatment Photos and Diagrams
ORIF of Capitellar Fracture
  • ORIF of left adult capitellar/medial epicondylar fracture.
    ORIF of left adult capitellar/medial epicondylar fracture.
  • Healed capitellar fracture after ORIF which allowed early active range of motion.
    Healed capitellar fracture after ORIF which allowed early active range of motion.

Post-treatment Management

  • The care and precautions related to immobilization devices for the capitellar 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 mobilized as early as possible.
  • Fractures that undergo stable internal fixation can typically be mobilized after 1-2 weeks if soft tissue healing is adequate.
  • 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 evaluated and used to create a ligament-specific rehabilitation protocol. Unrestricted ROM can begin at 6 weeks, and then progressive strengthening at 8–10 weeks after surgery so long as there is evidence of fracture healing.1
Complications

Complications1,15

  • Stiffness
  • Post-traumatic arthritis
  • Non-union
  • Cubitus valgus
  • Heterotopic bone formation
  • Avascular necrosis
  • Neurologic complications
  • Fixation failure
  • Post-traumatic osteoarthritis
  • Osteomyelitis
  • Ulnar nerve injury
  • Instability
  • Infection
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.11
    • However, although ORIF is the preferred surgical treatment for displaced capitellar fractures and has been the most studied procedure, evidence to support this approach is limited to small, noncomparative case series.1
  • Reports of successful outcomes following closed reduction of capitellar fractures have been documented, but studies comparing the outcomes between surgery and conservative treatment for these injuries are lacking.1,4
  • Arthroscopic Assisted Internal Fixation (AARIF) is becoming an increasingly popular, minimally invasive option for capitellar fractures, but research on the effectiveness of this procedure is still scarce.1
  • Although most patients eventually regain functional ROM after surgery, residual stiffness is common and may require reoperation.
  • Conditions that have been associated with a poor prognosis include significant capitellar articular injury, injury to the supporting bony architecture, posterior comminution of the lateral condyle, multiple articular fragments, and reoperation.4
Key Educational Points
  • Evidence-based treatment recommendations for capitellar 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 comparison. Thus, treatment decisions should generally be based on the fracture characteristics and presence of concomitant injury—or injuries.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 a shift toward surgical intervention—particularly ORIF—when managing these injuries.15
  • Healthcare providers must investigate for concomitant injury during the diagnosis of capitellar fractures, such as trochlear fractures, lateral collateral ligament (LCL) or medial collateral ligament (MCL) injuries, or ipsilateral fractures (e.g., radial head fractures or epicondylar humeral fractures), which can have significant implications on treatment decisions.14
  • Surgeons 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
  • Capitellar fractures can lead to a reduction in the arm’s arc of motion. If this produces a loss of flexion of >30°, it will adversely impact the reach of the arm and can lead to a contracture from scarring of the soft tissues.4
  • For elbow injuries the exam should include a neurologic exam which assesses the median, radial, and ulnar nerves, as well as their more distal branches (e.g., anterior and posterior interosseous nerves and cutaneous branches).11
  • A thorough physical examination of these patients look for signs of an associated injuries—such as an elbow dislocation, LCL or MCL injury, or radial head fracture.1
  • Anteroposterior (AP), lateral, oblique, and radiocapitellar X-ray views of the elbow are necessary.1 The true lateral and AP views are extremely helpful in assessing distal humerus injuries, since capitellar fractures can easily be missed.12 The “double arc” sign—which represents the displaced capitellum and lateral trochlea—may be seen a lateral radiographic view.
  • Since plain radiographies cannot always identify subtle fracture planes and often underestimates the extent of comminution, a CT scan may be necessary to assist with classification and surgical planning.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. Singh, AP, Singh, AP, Vaishya, R, et al. Fractures of capitellum: a review of 14 cases treated by open reduction and internal fixation with Herbert screws. Int Orthop 2010;34(6):897-901. PMID: 19894049
  6. 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
  7. 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
  8. 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
  9. 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
  10. Meals, C and Meals, R. Hand fractures: a review of current treatment strategies. J Hand Surg Am 2013;38(5):1021-31. PMID: 23618458
  11. Miller, AN and Beingessner, DM. Intra-articular distal humerus fractures. Orthop Clin North Am 2013;44(1):35-45. PMID: 23174324
  12. Cheung, EV. Fractures of the capitellum. Hand Clin 2007;23(4):481-6. PMID: 18054675
  13. 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
  14. 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
  15. 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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