Capitellum Coronal Shear Fracture Rehabilitation: Flexion-Block Bracing Protocols

A capitellum fracture is an uncommon intra-articular coronal shear fracture of the distal humerus, accounting for approximately 1% of all elbow fractures. Typically caused by a fall onto an outstretched or slightly flexed hand where axial force is transmitted through the radial head directly into the anterior humeral articular surface, this injury shears the capitellum off the humeral column. Classified by Bryan and Morrey into Type I (Hahn-Steinthal: large osseous fragment with subchondral bone), Type II (Kocher-Lorenz: thin sliver of articular cartilage with minimal bone), Type III (Broberg-Morrey: severely comminuted), and Type IV (McKee: coronal shear extending into the trochlea). Because the capitellum has no muscular attachments, displaced fragments often rotate anteriorly and superiorly into the radial fossa, mechanically blocking elbow flexion. Modern treatment mandates anatomical open reduction and internal fixation (ORIF) using headless, countersunk cannulated mini-screws placed from anterior-to-posterior or posterior-to-anterior beneath the articular cartilage. Physiotherapy must restore joint mobility while protecting the reconstructed articular surface from damaging shear.

Domestic and Cultural Indian Realities

In an Indian domestic setting, everyday tasks frequently generate axial and rotational elbow shear forces. Pushing oneself up from low seating, such as a traditional wooden charpoy, low diwan, or bathroom stool (patla), concentrates upper body weight directly through the radiocapitellar joint, which can shear the capitellar repair; patients must rise using leg power and uninjured arm support. Culinary tasks like grinding spices on a stone sil-batta, wringing heavy cotton clothes, or kneading thick dough with a rolling pin (belan) produce repetitive compressive contact across the healing anterior cartilage and must be suspended for 10 weeks. Personal grooming routines like bathing with a handheld plastic mug (lota) require combined flexion and pronation; patients should use lightweight cups. Commuting in shared autorickshaws exposes the arm to sudden road shocks; wearing a supportive hinged brace locked within safe parameters shields the elbow from traumatic impact.

Clinical Biomechanics and Anatomical Healing

The capitellum is a hemispherical anterior-inferior projection of the distal humerus that articulates with the shallow cup of the radial head. During elbow flexion, the radial head glides anteriorly across the capitellar surface. In coronal shear fractures, the fragment is completely intra-articular and relies primarily on synovial fluid diffusion and limited metaphyseal blood vessels for healing. Countersunk headless compression screws provide absolute stability, drawing the articular fragment tightly against the humeral column without leaving hardware protruding into the joint space. However, terminal elbow extension past 30 degrees during early healing places significant shearing forces on the anterior articular surface. Utilizing an extension-block hinged brace restricts terminal extension while allowing protected flexion within an arc that keeps the radial head centred on the repair.

Validated Special Tests and Differential Diagnosis

Clinical evaluation assesses active and passive range of motion, checking for mechanical blocks to elbow flexion (where an anteriorly displaced fragment impinges in the radial fossa). Palpation assesses the lateral epicondyle and lateral collateral ligament (LCL) complex. Lateral radiographs demonstrate the classic double-arc sign (representing the displaced capitellum and lateral trochlear ridge). Differential diagnosis distinguishes isolated capitellum fractures from radial head fractures, lateral condyle fractures, and coronoid process disruptions using fine-slice 3D CT reconstructions.

Stage-by-Stage Functional Recovery Protocol

Phase 1 (Weeks 0 to 2 post-op) protects the surgical repair in an extension-block hinged elbow brace set to block extension beyond 45 degrees, while permitting active-assisted flexion up to 90 degrees. Active finger, thumb, and shoulder exercises begin immediately. Phase 2 (Weeks 2 to 6) advances the extension stop by 10 to 15 degrees every two weeks (30° at week 2, 15° at week 4), increasing flexion past 110 degrees, accompanied by gentle active forearm pronation and supination. Phase 3 (Weeks 6 to 12) discontinues the brace, progressing to low-load long-duration terminal extension stretches, light resistance exercises, and progressive functional domestic reach once radiographic union is verified.

Red Flags and Urgent Surgical Indicators

Seek immediate orthopaedic assessment if you experience a sudden, painful mechanical block that prevents you from bending or straightening your elbow, indicating screw loosening or fragment displacement. Tingling or numbness in the little and ring fingers suggests ulnar nerve irritation requiring evaluation. Worsening wound redness, warmth, or purulent drainage along lateral incisions indicates surgical site infection.

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