Summary

The “all in one” interpositional scaffold anchor implant displayed good clinical efficacy, high MRI-confirmed rotator cuff tendon repair healing, excellent patient outcomes, and good survivorship.

Abstract

Purpose

Historically, most rotator cuff tendon repair interventions have focused on “time zero” biomechanical repair strength characteristics. The primary study objective was to evaluate the survivorship of arthroscopic rotator cuff tendon repair using a novel “all in one” interpositional scaffold anchor implant designed to vent biological fluids to the repair site. A previous ovine study revealed superior biological healing and biomechanical load to failure results using this device compared to control conditions. The secondary study objective was to determine device clinical efficacy based on postoperative shoulder range of motion (ROM), shoulder muscle strength, clinical outcomes scores, and overall device safety.

Methods

A prospective multicenter clinical trial was performed at 7 different sites enrolling consecutive patients with 1.5 cm to 4 cm moderate-to-large size full thickness rotator cuff tendon tears that met study inclusion criteria. Seventy-one patients (64.8% men) were enrolled for surgical repair using the implant. Average subject age was 60.5 years (range = 40 to 76 years) and 11.3% were smokers. Clinical shoulder evaluations were performed using the American Shoulder and Elbow Society (ASES) score, the Veterans Rand-12 (VR-12) physical and mental health scores, and visual analog scale (VAS) shoulder pain and instability questions at 3 month, 6 month, and 1 year follow-up. At the 6 month follow-up, repeat MRI was also performed and reviewed by a fellowship-trained, board-certified, independent radiologist. The median duration during which subjects were unable to perform daily activities because of their injured shoulder was 60 days (range = 0 to 365 days). Median symptom duration was 15 months (range = 0.5 to 120 months). Thirteen subjects had a normal biceps tendon at time of rotator cuff repair while 44 underwent tenodesis, and 14 underwent tenotomy.

Results

By the 1 year follow up, two device failures (97.0% device survival rate) had occurred, 10 subjects had been lost to follow up, and 1 death occurred (unrelated to the study). Patient self-reported outcome scores displayed continual improvement from study entry at each follow up period. The median preoperative ASES score of 44.2 improved to 92.5 at 1 year. Similar findings were observed with the median preoperative VAS pain score of 5.5 improving to 0.5 at 1 year, and the median preoperative VR-12 physical health score improving from 35.3 to 49.2 at 1 year. The median VR-12 mental health score did not display significant changes between the preoperative and 1 year follow up (53.7 and 57.0), respectively. The shoulder instability VAS score improved from the preoperative median score of 3.2 to 0.9 at 1 year. Shoulder ROM displayed a median 46° active forward elevation improvement (from 116.1° to 162.1°), and median 18.2° active adducted external rotation improvement (from 39.1° to 57.3°) between preoperative and 1 year follow up evaluations. At 6 months post-surgery, 52 subjects underwent repeat MRI. Sixteen subjects had experienced a rotator cuff tendon re-tear (31%). However, only 3 re-tears occurred at the footprint repair site (19% of all re-tears), with the rest occurring in tendon medial to the footprint. This observation confirmed that the previously torn tendon at the repair site had healed to the bone. One device failure was associated with an infection requiring implant removal, irrigation and intravenous antibiotic administration. No other major device related complications were observed.

Conclusion

Findings confirm the clinical efficacy, high healing rate, and safety of this “all in one” interpositional scaffold anchor implant for moderate-to-large size rotator cuff tendon tear repair. Significant shoulder function and symptom improvements were observed at each follow up relative to the preoperative state with good survivorship and minimal implant related complications.