SS Burkhart

One hundred two type II SLAP lesions without associated anterior instability, Bankart lesion, or anterior inferior labral pathology were surgically treated under arthroscopic control. There were three distinct type II SLAP lesions based on anatomic location: anterior (37%), posterior (31%), and combined anterior and posterior (31%). Preoperatively, the Speed and O'Brien tests were useful in predicting anterior lesions, whereas the Jobe relocation test was useful in predicting posterior lesions. Rotator cuff tears were present in 31% of patients and were found to be lesion-location specific. In posterior and combined anterior-posterior lesions, a drive-through sign was always present (despite absence of anterior-inferior labral pathology or a Bankart lesion) and was eliminated by repair of the posterior component of the SLAP lesion. We conclude that SLAP lesions with a posterior component develop posterior-superior instability that manifests itself by a secondary anterior-inferior pseudolaxity (drive-through sign), and that chronic superior instability leads to secondary lesion-location-specific rotator cuff tears that begin as partial thickness tears from inside the joint.

A previously undescribed mechanism of injury for posterior Type II SLAP lesions is described. The primary feature of this mechanism is a torsional peel-back of the posterosuperior labrum. Secure fixation by posterior-superior placement of suture anchors into the posterosuperior corner of the glenoid is essential. The repair must be protected against torsional peel-back forces by avoiding external rotation beyond 0 degrees for 3 weeks.

Biodegradable polymers, especially those belonging to the family of polylactic acid (PLA) and polyglycolic acid (PGA), play an increasingly important role in orthopaedics. These polymers degrade by hydrolysis and enzymatic activity and have a range of mechanical and physical properties that can be engineered appropriately to suit a particular application. Their degradation characteristics depend on several parameters including their molecular structure, crystallinity, and copolymer ratio. These biomaterials are also rapidly gaining recognition in the fledging field of tissue engineering because they can be fashioned into porous scaffolds or carriers of cells, extracellular matrix components, and bioactive agents. Although their future appears to be bright, several questions regarding the biocompatibility of these materials linger and should be addressed before their wide-scale use. In the context of musculoskeletal tissue, this report provides a comprehensive review of properties and applications of biodegradable PLA/PGA polymers and their copolymers. Of special interest are orthopaedic applications, biocompatibility studies, and issues of sterilization and storage of these versatile biomaterials. Also discussed is the fact that terms such as PLA, PGA, or PLA-PGA do not denote one material, but rather a large family of materials that have a wide range of differing bioengineering properties and concomitant biological responses. An analysis of some misconceptions, problems, and potential solutions is also provided.

SUMMARY: The author has previously elucidated and advocated various biomechanical principles for application in rotator cuff repair. This article is an attempt to link all these concepts together into a unified stepwise approach to arthroscopic rotator cuff repair that will maximize the strength of the repair for all tear configurations.

Secure arthroscopic repair of rotator cuff tears and Bankart lesions requires tight knots (knot security). Equally important, but usually overlooked, is the tightness of the suture loop (loop security). This study compared loop security in knots tied with No. 1 PDS suture using three different methods: (1) hand-tied, (2) single-hole standard knot pusher, and (3) cannulated double-diameter knot pusher. The results of this study show that the double-diameter knot pusher maintained tight suture loops that were equivalent in circumference to hand-tied loops and were significantly tighter than suture loops tied with a standard single-hole knot pusher. This study highlights the fact that loop security is equally important to knot security in tissue fixation.