The insertional footprint of the rotator cuff: an anatomic study.

PURPOSE: The purpose of this study was to define the entire rotator cuff footprint and relate it to known, easily identifiable landmarks as a guide for both open and arthroscopic rotator cuff repair. Anatomic: Gross and microscopic. METHODS: The myotendinous units of the rotator cuff and their insertions onto the humerus were dissected in 20 fresh-frozen cadavers. The separate tendon insertions were identified, and their length and width measured. The character and exact anatomy of the tendons were also noted. The entire insertion was measured and referenced to the articular surface, biceps groove, and bare area of the humerus. In a separate part of the study, 6 cadavers were decalcified and thin-sliced through the supraspinatus tendon insertion. This insertion was evaluated via scanning electron microscopy (SEM). RESULTS: Our findings demonstrated a consistent pattern at the insertion of the rotator cuff. The horseshoe-shaped insertion tapers away from the articular surface in a superior-to-inferior direction. Interdigitation of the muscle units may be noted, particularly between the supraspinatus and the infraspinatus. Average maximum insertional lengths and widths were as follows: subscapularis (SC): 40 x 20 mm; infraspinatus (IS): 29 x 19 mm; supraspinatus (SS): 23 x 16 mm; and teres minor (TM): 29 x 21 mm. The SC inserted on the lesser tuberosity adjacent to the biceps groove at the edge of the articular surface. It tapered away 18 mm at its inferior border. The SS inserted at the articular surface along its entire insertion from the bicipital groove to the top of the bare area. The IS wrapped the posterior border of the SS superiorly at the articular surface and tapered away inferiorly, framing the bare area. SEM microscopy showed the SS to be adherent to the edge of the articular surface medially. As it filled the sulcus, its lateral edge extended over the edge of the greater tuberosity. CONCLUSIONS: A consistent pattern was noted at the insertional anatomy of the rotator cuff. This anatomy was related to known, easily identifiable landmarks and may serve as a guide for evaluation of size, location, and propagation patterns of rotator cuff tears, as well as for their repair. CLINICAL RELEVANCE: Knowledge of the insertional anatomy of the rotator cuff can facilitate grading and repair of rotator cuff tears.

The biomechanical effects of low-dose irradiation on bone-patellar tendon-bone allografts.

BACKGROUND: Despite evidence that low-dose irradiation of 2 Mrad (20 kGy) is not virucidal for patellar tendon allografts and reduces tissue strength, many tissue bank protocols include low-dose irradiation. HYPOTHESIS: Maintaining tissue mechanical integrity may be particularly relevant toward accelerated rehabilitation of the injured knee, where the cyclic function of patellar tendon allografts is critical. STUDY DESIGN: Controlled laboratory study. METHODS: The cyclic and failure mechanical properties of paired bone-patellar tendon-bone allografts, with and without current low-dose irradiation of 20 kGy, were evaluated. Specimens were loaded from 50 N to 250 N for 1000 cycles at 0.5 Hz and subsequently loaded to failure at a strain rate of 100% per second. RESULTS: After 1000 cycles, grafts elongated 27% more when irradiated than when not (4.4 +/- 1.5 mm vs 3.4 +/- 1.0 mm; P = .03). Failure load averaged 1965 +/- 512 N for irradiated grafts and 2457 +/- 647 N for nonirradiated grafts (P = .007). CONCLUSIONS: The diminished strength of irradiated grafts may contribute to overt anterior cruciate ligament graft failure, and the increase in cyclic elongation may also be detrimental to graft function. CLINICAL RELEVANCE: These results suggest that one should consider the use of nonirradiated allografts as an alternative to irradiated grafts in anterior cruciate ligament reconstruction.

Surgical treatment of Achilles tendinitis by decompression of the retrocalcaneal bursa and the superior calcaneal tuberosity.

BACKGROUND: Initial nonoperative treatment of pain at the Achilles tendon, often referred to as "tendinitis," is not always successful. HYPOTHESIS: Surgical treatment is effective for patients with insertional tendinitis unrelieved by nonoperative measures. STUDY DESIGN: Retrospective cohort study. METHODS: Thirty-five patients (41 feet) who had painful Achilles tendon syndrome unrelieved by 6 months of nonoperative measures were treated surgically. The technique consisted of a single incision along the lateral border of the Achilles tendon. The dissection exposed the retrocalcaneal bursa and fat pad, which were completely excised along with any scarred and thickened paratenon. A partial calcaneal exostectomy of the tubercle was performed. RESULTS: At a minimum follow-up of 20 months (average, 39), the patients' pain scores (rated from 0 to 6) improved from 4.7 (SD, 1.1) preoperatively to 1.5 (SD, 1.3); 90% had complete or significant relief of symptoms, 10% felt improved, and none felt unchanged or worse. CONCLUSIONS: Surgical treatment of chronic Achilles tendon pain with resection of the prominent tuberosity, complete debridement of the bursa, excision of thickened, scarred paratenon, and removal of accessible calcific deposits within the tendon is an effective treatment.