Faculty Bibliography

PURPOSE: The purpose of this study was to evaluate the effect of hybrid femoral fixation with bioabsorbable interference screws (BioRCI; Smith & Nephew Endoscopy, Andover, MA) and EndoButton CL (Smith & Nephew Endoscopy) fixation. METHODS: Biomechanical testing of 3 different fixation techniques was performed by use of porcine hind-limb distal femurs and mature bovine extremity common extensor tendons. Two independent testing sessions were examined. The first testing session (group A) compared femoral fixation via the EndoButton CL device (n = 6) with femoral fixation via the EndoButton CL device with the addition of a BioRCI screw (n = 6). The second testing session (group B) compared femoral fixation via BioRCI screws alone (n = 6) with femoral fixation via the EndoButton CL device with the addition of a BioRCI screw (n = 6). The femur-graft complex was cyclically loaded between 50 and 250 N at 1 Hz for 1,000 cycles. After cycling, the amount of graft slippage was determined by measuring the change in grip-to-grip distance. The complex was then loaded to failure at 1 mm/s, and the ultimate tensile strength, stiffness, and mode of failure were determined. RESULTS: In group A the addition of an interference screw to the EndoButton CL fixation increased the ultimate tensile strength (1,364.7 +/- 102.4 N for EndoButton CL alone v 1,449.3 +/- 94.4 N for combined technique, P = .035) and stiffness (195.5 +/- 12.1 N/mm for EndoButton CL alone v 307.3 +/- 54.9 N/mm for combined technique, P = .004) and decreased the amount of graft slippage (2.6 +/- 0.5 mm for EndoButton CL alone v 2.0 +/- 0.3 mm for combined technique, P = .017). In group B the addition of the EndoButton CL device to interference screw fixation significantly increased the ultimate tensile strength (643.5 +/- 148.4 N for BioRCI screws alone v 1,290.3 +/- 254.4 N for combined technique, P = .004) but had no effect on stiffness (315.7 +/- 38.9 N/mm for BioRCI screws alone v 341.5 +/- 64.0 N/mm for combined technique, P = .267) or graft slippage (2.7 +/- 1.0 mm for BioRCI screws alone v 2.0 +/- 0.6 mm for combined technique, P = .087). CONCLUSIONS: Our study shows that hybrid femoral fixation of double-looped gracilis-semitendinosus grafts via the EndoButton CL device and a bioabsorbable interference screw is stronger than interference or EndoButton CL fixation alone with respect to ultimate tensile strength, stiffness, and slippage. The addition of an interference screw to suspensory fixation via the EndoButton CL device increased the ultimate tensile strength from 1,360 N to 1,450 N, improved reconstruction stiffness from 200 N/mm to 300 N/mm, and decreased the amount of graft slippage resulting from cyclic loading from 2.6 mm to 2.0 mm. CLINICAL RELEVANCE: The hybrid fixation of the EndoButton CL device and an interference screw is a stronger and stiffer construct than either device alone and allows for aperture fixation, which may translate into better clinical results

BACKGROUND: The effect of arthroscopic rotator interval closure on glenohumeral motion and translation is not well understood, nor is the ideal location or number of sutures required for closure. HYPOTHESIS: The number of arthroscopic rotator interval closure sutures and their placement will have a significant effect on glenohumeral range of motion and anterior-posterior translation. STUDY DESIGN: Controlled laboratory study. METHODS: Using a custom testing apparatus, the authors measured range of motion in 12 fresh-frozen cadaveric shoulders; anterior-posterior translation in adduction and neutral rotation was measured in 9. Specimens were initially tested without sutures and then tested after 3 interval closures using a random sequence of (1) an isolated medial suture at the level of the glenoid, (2) an isolated lateral suture 1 cm lateral to the glenoid, or (3) both sutures followed by removal of all sutures. RESULTS: Analysis of variance demonstrated that interval closure had a significant effect on decreasing flexion (mean, 6 degrees ), external rotation (mean, 10 degrees ), and anterior translation (mean, 3 mm) of the adducted shoulder. There was no significant difference between the 3 interval closures in any of the tests. CONCLUSION: Arthroscopic interval closure produced significant decreases in range of motion and anterior-posterior translation. The effects of single lateral or medial suture closures were similar to the use of 2 sutures. CLINICAL RELEVANCE: This study suggests that the initial effect of arthroscopic rotator interval closure on anterior translation of the shoulder will be similar whether 1 or 2 sutures are used. In vivo studies are necessary to determine if the effect of these 2 methods would be the same over time

PURPOSE: To retrospectively assess magnetic resonance (MR) imaging features of radial tunnel syndrome. MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was waived for the retrospective HIPAA-compliant study. MR images of 10 asymptomatic volunteers (six men, four women; mean age, 30 years) and 25 patients (11 men, 14 women; mean age, 49 years) clinically suspected of having radial tunnel syndrome were reviewed for morphologic and signal intensity alterations of the posterior interosseous nerve and adjacent soft-tissue structures. MR images of the asymptomatic volunteers were reviewed to establish the normal appearance of the radial tunnel. MR images of the symptomatic patients were evaluated for the following: signal intensity alteration and morphologic alteration of the posterior interosseous nerve; the presence of mass effect on the posterior interosseous nerve such as the presence of bursae, a thickened leading edge of the extensor carpi radialis brevis, or prominent radial recurrent vessels; signal intensity alteration within the depicted forearm musculature such as edema or atrophy; and signal intensity changes at the origin of the common extensor and common flexor tendons, which would suggest a diagnosis of epicondylitis. RESULTS: All images of volunteers demonstrated normal morphology and signal intensity within the posterior interosseous nerve and adjacent soft tissues. Two volunteers had borderline thickening of the leading edge of the extensor carpi radialis brevis. Thirteen patients (52%) had denervation edema or atrophy within muscles (supinator and extensors) innervated by the posterior interosseous nerve. One patient had isolated pronator teres edema. Seven (28%) patients had the following mass effects along the posterior interosseous nerve: thickened leading edge of the extensor carpi radialis brevis (n = 4), prominent radial recurrent vessels (n = 1), schwannoma (n = 1), or bicipitoradial bursa (n = 1). The rest of the patients had either normal MR imaging findings (n = 4) or lateral epicondylitis (n = 2). CONCLUSION: Muscle denervation edema or atrophy along the distribution of the posterior interosseous nerve is the most common MR finding in radial tunnel syndrome

The fixation of displaced greater tuberosity fractures with 5-0 Fiberwire, Fiberwire tape, and 5-0 Ethibond sutures was compared in 12 pairs of cadaveric humeri. A simulated fracture was created and fixed with suture in a figure-of-eight pattern. The tuberosity was cyclically loaded and its displacement measured. There was no statistical difference in fixation stability between the three suture types

A case of a 26-year-old male with symptoms resulting from loose bodies residing in a sublabral recess is presented. Operative intervention using the standard arthroscopic portals in addition to an accessory posterior portal was successful in removing the loose bodies and approximating the edges of the sublabral foramen. The shoulder is a complex region made up of numerous anatomic structures, which if damaged may be responsible for a patient's pathology. Normal anatomic variations also exist, which in certain situations, may contribute to a patient's presentation. One example of a normal anatomic variation is the sublabral foramen, which represents an unattached anterosuperior labrum

There are a variety of arthroscopic devices used to pass sutures through the rotator cuff for its repair. Because they vary in size and shape, it is possible that they could damage the cuff and affect the integrity of the repair. We chose four devices for assessment--SutureLasso (Arthrex, Naples, FL), straight BirdBeak (Arthrex, Naples, FL), Viper (Arthrex, Naples, FL), and a #7 tapered Mayo needle--and performed cuff reattachments in four paired shoulders using suture anchors. These repairs were cycled and tested to failure. The SutureLasso and Mayo needle repairs failed at approximately 285 N whereas the BirdBeak and Viper failed during cycling at 150 N. It appears that the devices, which made the bigger holes in the cuff, can compromise the integrity of the repair

In a recent experiment examining the effect of interference screw sizing on the fixation stability of multi-strand anterior cruciate ligament grafts, we noticed a large variation in fixation strengths and attributed it to the suturing of the grafts and its interaction with the screw. We performed an experiment using interference screws for fixation of hamstring grafts within a bone tunnel model to compare how the presence of sutures affected graft fixation. We found that having sutures along the region of the graft that contacts the screw within the bone tunnel can increase graft fixation strength 100%

Recent experimental studies suggest that the use of suture anchors for rotator cuff tear (RCT) repair transfers the 'weak link' to the suture-tendon interface where failure occurs as the sutures cut through the tendon. The purpose of this study was to evaluate the effect of using a suture augmentation button on the fixation strength of rotator cuff tendon repair. A 1.5 cm by 2 cm defect was created in the supraspinatus tendon of seven cadaveric shoulder pairs and two suture anchors inserted in each humerus for suture attachment. For one of each pair, the defect was repaired with sutures placed in a horizontal mattress configuration. The other side was repaired with the sutures being passed through low profile, bioabsorbable buttons placed on the bursal tendon surface prior to knot tying. The supraspinatus tendon was cyclically loaded at a physiologic rate and load (33 mm/sec and 180 N, respectively). The number of loading cycles was recorded when the specimens developed 0.75 cm and 1.5 cm gaps at the repair site. The specimens were then tested to failure. Specimens in the unaugmented group developed 0.75 cm and 1.5 cm gaps at an average of 135 cycles and 362 cycles, respectively. The button augmented group developed these gaps at average of 420 cycles and 708 cycles, respectively. These differences were statistically significant (p < 0.05). The gaps progressively increased in all specimens, which eventually failed by suture cutting through tendon in all specimens. This study demonstrates that in vitro, suture augmentation with a low profile, bioabsorbable button provides significantly enhanced fixation when using suture anchors to repair torn rotator cuff tendon. This device may be a useful adjunct to current methods of rotator cuff repair

To encourage consistent care for patients with musculoskeletal complaints, the AAOS developed treatment algorithms to aid primary care physicians in the management of these patients. A survey was designed to assess whether a random group of primary care physicians treated their patients in a manner consistent with these algorithms. The AAOS algorithm for shoulder pain was used to develop a questionnaire for primary care physicians. An Internet company provided access to a national base of physicians who volunteered to complete the survey. Ten questions were presented on five shoulder conditions: rotator cuff disease, fractures, instability, arthritis, and frozen shoulder The 'correct' answer was based upon the AAOS algorithm. The survey was completed by 706 physicians who treated variable (one to greater than ten) numbers of shoulder patients per month. Forty-eight percent of the physicians treated acute trauma according to the algorithm, 87% treated arthritis, and 58% treated instability. Only 46% of physicians chose the correct answer for an acute rotator cuff tear and 29% for chronic rotator cuff symptoms. Forty-four percent followed the algorithm for frozen shoulder. Overall only 49% of the patients described were treated according to the AAOS algorithms. Based on the number of shoulder patients seen each month, in one month over 2000 patients could be tested by the surveyed physicians in a manner inconsistent with the treatment algorithms, suggesting the need for improved musculoskeletal education for primary care physicians