Arthroscopic Distal Clavicle Resection: A Biomechanical Analysis of Resection Length and Joint Compliance in a Cadaveric Model

Purpose: The purposes of this study were to assess the effects of a distal clavicle resection of less than 5 mm on bony contact and compliance in the acromioclavicular (AC) joint and to localize areas of persistent contact in the AC joint. The hypothesis of this study was that AC contact can be avoided by excising less than 5 mm of bone from the distal clavicle. Methods: Ten human AC joints underwent compressive loading of the distal clavicle into the acromion after the following: disk excision, distal clavicle resection of 2.5 mm, and distal clavicle resection of 5 mm. The joint resistance force, stiffness, and presence and location of contact were monitored. Results: Excising 2.5 mm or less resulted in no bone-to-bone abutment in 6 of 10 specimens. A 5-mm resection resulted in successful decompression in all specimens. The specimens that required a 5-mm resection had minimal contact after the 2.5-mm resection (inferior-posterior quadrant only). AC joint stiffness decreased significantly with increasing amounts of clavicular resection (P = .01). Conclusions: A 5-mm distal clavicle resection guaranteed no abutment but decreased joint stiffness. Persistent contact occurred only in the inferior-posterior quadrant of the joint after a 2.5-mm resection. Clinical Relevance: These findings support the efficacy of a 5-mm distal clavicle resection for eliminating bony contact but suggest that there is a bony contribution to AC joint stiffness. A resection of 2.5 to 5.0 mm could be adequate if care is taken to excise a greater depth of bone in the inferior-posterior quadrant.