Osteochondral Autograft Options for Reconstruction of Intra-articular Distal Humerus and Proximal Ulna Injuries in Physiologically Young Patients.

PURPOSE: Surgical options are limited for distal humerus and proximal ulna injuries with articular bone loss in physiologically young patients. Osteochondral grafts are a potential treatment option between open reduction internal fixation and arthroplasty that does not impart lifelong activity restrictions and has longer longevity. Feasible graft harvest sites that match the surface geometry of the distal humerus and proximal ulna are unknown. This study assesses the surface geometry of potential grafts with known well-defined donor site morbidity for the reconstruction of distal humerus and proximal ulna articular defects.

METHODS: Osteochondral autograft harvest sites include the radial head, pisiform, trapezium, fibular head, and proximal and distal phalanx of the hallux. Between 2015 and 2022, 12 patients, who were in the hospital for problems unrelated to the current study and coincidentally had computed tomography (CT) scans of an intact elbow and an intact autograft harvest site, were identified at Massachusetts General Brigham. Fifteen elbow CT scans and 25 harvest site CT scans were analyzed. Three-dimensional segmentations of the graft harvest sites were constructed using Materialise (Mimics 13.0; 3-matic). The average morphological differences in surface geometry of subchondral bone between each site were quantified using surface topographic mapping.

RESULTS: Viable autograft harvest sites with <2 mm difference in surface morphology for the distal humerus include hallux proximal phalanx (1.65 ± 0.85 mm), whereas for the proximal ulna include fibular head (0.72 ± 0.63 mm), radial head (1.01±0.67 mm), and hallux proximal phalanx (1.01 ± 1.19 mm).

CONCLUSIONS: Based on geometric characteristics, several viable osteochondral graft options exist for intra-articular injuries to the ulnohumeral joint. These findings may guide future cadaveric and in vivo studies to assess the effect of autograft reconstruction on elbow stability, elbow function, and donor site morbidity.

TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.