Efficacy of Marrow-Stimulating Technique in Arthroscopic Rotator Cuff Repair: A Prospective Randomized Study (SS-14)

Abstract

To evaluate the efficacy of marrow-stimulating technique by microfracturing greater tuberosity during arthroscopic rotator cuff repair. The hypothesis of the study was that microfractures can improve outcome of rotator cuff repair. Eighty patients with a full-thickness tear of the posterior-superior rotator cuff underwent an arthroscopic repair. All procedures were performed by using single-row repair technique with metal suture anchors alone or combined with side-to-side repair. Patients were divided in two groups of 40 cases each. In group 1, standard repair was performed; in group 2, microfractures of the greater tuberosity were performed to enhance tendon repair. Exclusion criteria were: partial-thickness and irreparable cuff tears, subscapularis tears, labral pathology, os acromiale, degenerative arthritis of glenohumeral joint, symptomatic arthritis of acromioclavicular joint, rotator cuff arthropathy, previous surgery to the same shoulder, and workers' compensation claims. Sample size was calculate in order to achieve power equal to 0.80. Results were evaluated at minimum two-year follow-up. Clinical outcome was assessed using the DASH self-administered questionnaire (primary outcome) and the Constant score normalized for age and gender. Structural integrity of repaired tendons was evaluated with MRI. The following independent variables were considered: age, gender, dominance, type of work, timing of symptoms, size, shape and retraction of the cuff tear, fatty degeneration of rotator cuff muscles, treatment of the biceps tendon, repair technique (anchors or anchors and side to side), and number of anchors. Matched-pair comparison was performed for each independent variable. Comparisons between groups for clinical outcomes were adjusted for baseline values. Multivariate linear and logistic regression analysis was performed to determine which variables were independently associated with the outcome. Significance was set at p < .05. Mean follow-up was 28 months. Seven patients were lost at follow-up (2 patients in group 1, and 5 in group 2, respectively). Comparison between groups did not show significant differences for each independent variable. Mean DASH score was 28.6 points in group 1 and 23.3 points in group 2. Mean normalized Constant score was 92.7 points in group 1 and 94.5 points in group 2. Differences between groups were not significant. Tendon healing rate assessed by MRI was 52.6% (20/38) in group 1 and 65.7% in group 2, without significant difference between groups. However, stratified analysis for size of cuff tear showed that group 2 had significantly greater healing rate than group 1 for large tears (p = 0.040). Multivariate analysis showed that age, gender, timing of symptoms, tendon retraction and fatty degeneration significantly and independently affected clinical outcomes. Influence of microfractures on healing rate of repaired tendons approximated to significance (p = 0.07). Marrow-stimulating technique by microfracturing greater tuberosity during arthroscopic rotator cuff repair did not influence clinical outcome, but significantly improved healing rate of large rotator cuff tears.