Comparison of elbow contracture release in elbows with and without heterotopic ossification restricting motion.

We compared 16 patients with post-traumatic heterotopic ossification (HO) restricting elbow motion (but not complete bony ankylosis) after elbow trauma with 21 patients with capsular contracture alone to test the hypothesis that HO is associated with diminished motion after release. Patients with burns or head injury were excluded. The preoperative flexion arc averaged 59 degrees in the HO cohort and 52 degrees in the capsular contracture cohort. The mean flexion arc after the index surgery improved by 54 degrees to a mean arc of 113 degrees in the HO cohort and by 35 degrees to a mean of 87 degrees in the capsular contracture cohort (P = .02). After all subsequent procedures (including procedures to address residual stiffness in 1 patient in the HO cohort and 4 patients in the capsular contracture cohort), the flexion arc averaged 116 degrees in the HO cohort and 98 degrees in the capsular contracture cohort (P = .19). Open release of post-traumatic elbow stiffness is more effective when HO hindering motion is removed than when there is capsular contracture alone.

Reference points for radial head prosthesis size.

PURPOSE: Metallic radial head implants are useful when the radial head cannot be repaired reliably and when either the elbow or the forearm is unstable. Problems arise when the radial head prosthesis is too thick, causing erosions of the capitellum and incongruity of the ulnohumeral joint. We used quantitative 3-dimensional computed tomography analysis to investigate the relative height of the radial head relative to the lateral edge and central ridge of the coronoid process as reference points for optimal insertion of a radial head prosthesis. METHODS: Seventeen computed tomography scans of the elbow were analyzed. The anatomic coronal plane of the forearm was determined using 3-dimensional images and a 2-dimensional image bisecting the articular surface of the radial head was created in this plane. The distance between the plane of the articular surface of the radial head and parallel planes at the most proximal aspect of the coronoid (the central ridge) and the lateral edge of the coronoid articular surface were measured. Negative values indicate the radial head is proximal to the coronoid. RESULTS: The average distance between the planes defined by the radial head articular surface and the coronoid central ridge was -0.8 mm. The average distance between the planes defined by the radial head articular surface and the lateral edge of the coronoid articular surface was -0.9 mm. CONCLUSIONS: Because the radial head was on average only 0.9 mm more proximal than the lateral edge of the coronoid process and because the key is to not overstuff the joint a useful general guideline would be to place the plane of the articular surface of the radial head even with or just slightly more proximal than the lateral edge of the coronoid articular surface. Considering the substantial variability of the normal height of the articular surface of the radial head with respect to that of the coronoid, preoperative radiographs of the opposite elbow may be useful to avoid overstuffing the elbow.