Clavicular tunnel widening in chronic acromioclavicular joint instabilities after primary versus revision arthroscopically-assisted acromio- and coracoclavicular stabilization.

Purpose: To evaluate joint reduction (loss of reduction [LOR]; dynamic posterior translation [DPT]) and clavicular tunnel widening (cTW) in patients treated with arthroscopically-assisted acromioclavicular joint (ACJ) stabilization after previously failed nonoperative versus surgical treatment.

Methods: Patients undergoing arthroscopically-assisted ACJ stabilization (bidirectional tendon allograft with a low-profile TightRope) after previously failed nonoperative versus surgical treatment were included retrospectively. Bilateral anteroposterior stress views served for evaluating LOR (side-comparative coracoclavicular distance [CCD]) and cTW at a 6-weeks- and 6-months-follow-up (FU) and for evaluating the filling ratio (FR, vertical device insertion depth relative to clavicle height) at the 6-weeks-FU. Postoperative DPT was assessed on Alexander's views.

Results: Twenty-seven patients (20 male, mean age 46.1 ± 14.8 years) were included (prior treatment: nonoperative:  = 15; surgical:  = 12). There were no differences in LOR, DPT or cTW between groups postoperatively. Initial CCD-symmetry at the 6-weeks-FU (CCD: -0.1 mm [95% confidence interval, CI, -2 to 1.4 mm]) was followed by LOR at the 6-months-FU (CCD: -3.5 mm [95% CI, -5.2 to -1.9 mm];  < 0.001). cTW increased towards the inferior cortex, compared to the superior cortex and the intermediate level ( < 0.001, respectively). cTW at the inferior cortex was associated with more LOR ( = -0.449;  = 0.024) and DPT ( = 0.421;  = 0.036), dependent on a smaller FR ( = -0.430;  = 0.032).

Conclusion: Patients undergoing arthroscopically-assisted ACJ stabilization for chronic bidirectional ACJ instabilities showed comparable radiologic results after previous nonoperative versus surgical treatment. cTW increased towards the inferior cortex and was associated with recurrent vertical and horizontal instability, related to a smaller FR. More research into reduced cTW, for example, by a more filling device, should be performed.

Level Of Evidence: Level III, retrospective comparative study.