Hypothesis: Conservative rehabilitation after arthroscopic rotator cuff repair does not result in long-term stiffness and improves rates of tendon healing Materials and methods: We retrospectively evaluated 43 patients with full-thickness rotator cuff tears who underwent a standardized, conservative protocol of full-time sling immobilization without formal therapy for 6 weeks after arthroscopic repair. At 6 to 8 weeks of follow-up, we categorized patients as "stiff" if they demonstrated forward elevation of less than 100 degrees and external rotation of less than 30 passively; all others were designated "nonstiff" Active range of motion in forward elevation, external rotation, and internal rotation was assessed at 3 months, 6 months, and 1 year. American Shoulder and Elbow Surgeons (ASES) and Constant-Murley scores were assessed at 1 year Follow-up magnetic resonance imaging (MRI) was obtained in all patients to assess tendon healing. Results: Ten patients (23%) were considered stiff after rotator cuff surgery At 1 year, there was no difference in mean forward elevation (166 degrees vs 161 degrees, P = 2), external rotation (62 degrees vs. 58 4 degrees, P = .5), or internal rotation (T7.4 vs T8.2, P = .07) between the stiff and nonstiff groups. respectively There were no differences in final ASES (83 vs 79. P = 57) and Constant-Murley scores (77 vs 74, P = 5) Repeat MRI suggested a trend toward a lower retear rate among the stiff patients (70% intact in stiff group vs 36% in nonstiff group, P = .079). Two clinically significant cuff retears occurred in the nonstiff cohort. Discussion: Concerns for recalcitrant stiffness have led some to favor early postoperative therapy We found that early restriction of motion did not lead to long-term stiffness after arthroscopic rotator cuff repair, even in patients who were clinically stiff in the early postoperative period. Conclusions: Sling immobilization for 6 weeks after arthroscopic rotator cuff repair does not result in increased long-term stiffness and may improve the rate of tendon healing. Level of evidence: Level IV, Case Series, Treatment Study. (C) 2010 Journal of Shoulder and Elbow Surgery Board of Trustees