Background: Flail or unstable elbow presents a difficult challenge for the elbow surgeon. This study reports the medium-term follow-up of 30 elbows in 25 patients, treated with two different designs of sloppy-hinged prosthesis: the Coonrad-Morrey and the snap-fit Souter-Strathclyde.

Methods: All patients treated over a 12 year period by a single surgeon were identified and reviewed. This included a detailed history of indications, complications, and subjective assessment (including Mayo Elbow Performance Scores, subjective satisfaction score, and SF-12 mental and physical disability questionnaire), as well as examination and radiographic review of preoperative and most recent xrays.

Results: 30 elbows in 25 surviving patients were assessed at an average postoperative period of 5.7 years. 17 Coonrad-Morrey and 13 snap-fit Souter-Strathclyde prostheses were implanted. 4 elbows (13.3%) have been revised. Average Mayo Elbow Performance score was 78.8 out of a top score of 100, with 15 classed as excellent, 5 good, 4 fair and 6 poor. Average subjective satisfaction with the operation was 4.5 out of a top score of 5. There was an average flexion arc of 104.7°, with 18 elbows ≥100°. 3 of the 17 Coonrad-Morrey elbows (17.6%) and 3 of the 13 snap-fit Souter-Strathclyde elbows (23.1%) demonstrated at least Grade 3 humeral radiolucency at the bone-cement interface. In the ulna, these figures were 6 out of 17 (35.3%) for Coonrad-Morrey elbows and 2 out of 13 (15.4%) for snap-fit Souter-Strathclyde elbows.

Conclusions: Sloppy-hinged elbow replacement is a safe procedure with a high subjective satisfaction level. Its main indication is as a salvage operation in patients with a functionally useless elbow due to failed primary replacement or non-union of distal humeral fracture.