Abstract
Introduction:
Reverse total shoulder arthroplasty (RTSA) has become an accepted surgical treatment for patients with severe deficiency of the rotator cuff. Despite the utility of RTSA in managing difficult shoulder problems, humeral rotation does not reliably improve and may even worsen following RTSA. Several approaches to increase active external rotation (aER) postoperatively have been proposed including the use of concomitant latissimus dorsi tendon transfer (LDTT) or the use of an increased lateral-offset glenosphere (LG). We hypothesized that clinical outcome and range of motion after RTSA with a +4 mm or +6 mm LG would be comparable to RTSA with LDTT in patients with a lack of aER preoperatively.
Methods:
An IRB-approved, prospective, single surgeon RTSA registry was reviewed for patients treated with LDTT or LG for preoperative aER deficiency with minimum 1-year follow-up. Patients qualified for aER deficiency if they had a positive ER lag sign or less than or equal to 10 degrees of aER preoperatively. Matched control groups with patients that did not have preoperative lack of aER and were not treated with LDTT or LG were included for comparison. Outcomes measures included Constant-Murley score (CMS), American Shoulder and Elbow Surgeons (ASES) score, Subjective Shoulder Value (SSV), ASES Activities of Daily Living (ADL) score, Visual Analogue pain Scale (VAS), active forward elevation (aFE), active internal rotation (aIR), and aER. An independent, institutional biostatistician performed statistical analyses.
Results:
The LDTT group had 21 patients (10 male, 11 female) and the LG group had 16 patients (5 male, 11 female). CMS, ASES, SSV, ADL, VAS, and aFE were significantly improved in case and control groups following RTSA (P < .05). There was no significant difference in the degree of improvement of CMS, ASES, SSV, ADL, VAS or aFE between the LDTT group and its control group or the LG group and its control group (P > .05). aER was significantly improved in the LDTT and LG groups (P < .001), but did not improve significantly in either control group (P > .05) (Figure 1). The LDTT group had a significantly lower postoperative aER than its control group (P = .001), whereas the LG group had similar postoperative aER to its control group (P = .376) (Figure 1). The LG group had significantly greater aER preoperatively and postoperatively than the LDTT group (P < .001 and P = .013). There was no significant difference in degree of improvement of aER between the LDTT and LG groups (P = .212). The LDTT group had a significantly lower postoperative aIR than its control group (P=.025), whereas the LG group had similar postoperative aIR to its control group (P = .234). The LG group had significantly greater improvement in aIR than the LDTT group (P=.009).
Conclusion:
To our knowledge, this is the first series to compare outcomes of two common techniques used to improve aER following RTSA. In this series, we found overall similar improvements in outcomes between the groups. These results suggest that use of a LG may be preferable to LDTT given the relatively simplified surgical technique, similar improvement in aER, comparable clinical outcome scores, and the added benefit of improved aIR.
