Hidden instability in posttraumatic stiff elbows

Hidden instability could be one of the reasons for reoccurring stiffness after arthrolysis in posttraumatic elbows. Associated instability in stiff posttraumatic elbows is clinically hard to detect. Surgical treatment for instability and stiffness in the same surgical setting is challenging and has not been evaluated as of yet.

The primary hypothesis assumes (1) the existence of a posttraumatic "stiff and unstable elbow" and (2) that coexisting instability can be detected by arthroscopic instability testing. The secondary objective was to report the midterm results after arthrolysis and ligament stabilization in the stiff and unstable elbow.

From 2005 to 2015, 55 patients received arthroscopic arthrolysis of the elbow due to posttraumatic elbow stiffness at our institution. The arthroscopic instability was categorized into three grades with a switching stick: grade I (= stable), grade II (mild instability) and grade III (grossly instable). In cases of persisting instability (grade II-III), a ligament stabilization procedure was performed and all patients were followed up clinically at a minimum of 12 months. Besides ROM and clinical joint stability, PROs (patient reported outcomes) were assessed with the PREE-score (patient-rated elbow evaluation) and the Oxford-Elbow-score (OES). Furthermore, the MEPS (Mayo-elbow-performance-score) was assessed.

Out of 55 cases presenting for arthrolysis, coexisting elbow instability was detected during arthroscopic instability testing in 22 cases (40%). All 22 patients received additional ligament stabilization. At final follow-up 62.7 ± 35.7 months postoperatively, 20 patients (12 men; 8 women) with a mean age of 42 ± 16.8 were available. PREE, OES and MEPS were 19.8 ± 25.3, 37.5 ± 9.8 and 80 ± 14.5, respectively. ROM improved significantly from 95° ± 29° to 110° ± 24° postoperatively (p = 0.045). Five patients required revision arthrolysis within the follow-up period (20%). One patient demonstrated persisting instability (5%).

Intraoperative instability diagnostics during arthroscopic arthrolysis helps detect persisting posttraumatic instability and may provide a solid indication for a concurrent ligament stabilization procedure. This study is the first to present the postoperative results after arthrolysis with stabilization of the posttraumatic, stiff and unstable elbow. However, the results are heterogenic with 25% requiring revision arthrolysis. Therefore, the stiff but unstable elbow remains a complex clinical presentation in need of further investigations.

IV.