Faculty Bibliography

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

INTRODUCTION: It has been shown that the asymptomatic, dominant elbow of professional baseball pitchers can demonstrate magnetic resonance (MR) imaging signal abnormalities of the ulnar collateral ligament (UCL) consistent with a strain. The purpose of this study was to determine if younger, asymptomatic, adolescent baseball pitchers exhibit similar signal abnormalities in the UCL. METHODS: Magnetic resonance images of both elbows of 14 asymptomatic, young male baseball pitchers (ranging in age from 12 to 20 years) were performed on an outpatient basis using a 1.5-T Sigma MRI unit with a dedicated extremity coil to obtain T1 and T2 coronal and axial images which were subsequently evaluated by a musculoskeletal radiologist. Chronic tears of the UCL were suspected if the signal was attenuated or absent. Magnetic resonance images of the UCL were also evaluated for high-intensity signal or thinning. Morphologic changes such as complete tears, avulsions or thickening were identified. The images were classified into 4 grades from 0 to 3 depending on the degree of signal abnormality. RESULTS: No discrete tears were found in any of the subjects. For the dominant pitching arm, 4 of 14 subjects had increased thickness of the ulnar collateral ligament, 3 of 14 demonstrated Grade 1 changes, and 11 of 14 demonstrated no abnormal signal within the ligament. No focal tears were present in any of the subjects. Contralateral elbows in 13 of 14 patients demonstrated Grade 0 signals with 1 patient demonstrating morphological thickening of the ligament without increased signal. DISCUSSION: Signal abnormalities in the throwing elbow of asymptomatic, adolescent pitchers were uncommon. These pitchers may not have experienced sufficient pitching time to develop changes in the UCL

PURPOSE: Classification and treatment of tibial eminence fractures are determined by the degree of fragment displacement. A variety of surgical procedures have been proposed to stabilize displaced fractures using both open and arthroscopic techniques. Two common fixation techniques involve use of cannulated screws and sutures tied over an anterior tibial bone bridge. We are unaware of any biomechanical studies that have compared the strength of various techniques of fixation. TYPE OF STUDY: Biomechanical study in a cadaveric model. METHODS: Seven matched pairs of fresh-frozen human cadaveric knees were stripped of all soft tissue except the anterior cruciate ligament (ACL). Simulated type III tibial eminence fractures were created using an osteotome. Fragments of each matched pair were randomized to fixation with either a single 4-mm cannulated cancellous screw with a washer or an arthroscopic suture technique using 3 No. 2 Fiberwire sutures (Arthrex, Naples, FL) passed through the tibial base of the ACL and tied over bone tunnels on the anterior tibial cortex. Specimens were then loaded with a constant load rate of 20 mm/min, and load-deformation curves were generated. The ultimate strength and stiffness were computed for each curve. The failure mode for each test was observed. A paired 2-tailed t test was used to determine the statistically significant difference between the two methods. RESULTS: Specimens fixed with Fiberwire had a mean ultimate strength of 319 N with a standard deviation of 125 N. Those fixed with cannulated screws had a mean ultimate strength of 125 N with a standard deviation of 74 N. This difference was statistically significant (P = .0038). There was no significant difference between the mean stiffness of Fiberwire constructs (63 N; SD, 50 N) and the mean stiffness of the cannulated screw constructs (20 N; SD, 32 N). The failure modes of the Fiberwire constructs included 1 ACL failure, 3 failures of suture cutting through the anterior tibial cortex, and 3 of suture cutting through the tibial eminence fragment. The single mode of failure for the cannulated screw constructs was screw pullout of cancellous bone. CONCLUSIONS: The initial ultimate strength of Fiberwire fixation of tibial eminence fractures in these specimens was significantly stronger than that of cannulated screw fixation. CLINICAL RELEVANCE: It appears that Fiberwire fixation of eminence fractures provides biomechanical advantages over cannulated screw fixation and may influence the type of treatment one chooses for patients with tibial eminence fractures

Advances in medical treatment have led to improved life expectancy in patients with sickle cell hemoglobinopathies. Improved life expectancy has, in turn, led to an increasing number of patients with osteonecrosis requiring total hip arthroplasty. Patient evaluation begins with understanding the extent of the disease process and the patient's musculoskeletal manifestations (ie, pyogenic infection, marrow hyperplasia, osteonecrosis). A multidisciplinary approach to implementing effective preoperative treatment strategies increases the likelihood of a successful surgical outcome. Intraoperatively, consideration of bone stock, bone quality, and method of component fixation may help minimize the risk of eccentric reaming, perforation or fracture of either the acetabulum or the femur, and loosening. The optimal mode of acetabular and femoral fixation in these patients has not been conclusively determined, but recent results of cementless total hip arthroplasty have been encouraging. Although patients with sickle cell disease are at increased risk of medical and surgical complications, total hip arthroplasty in the appropriately selected patient can provide significant pain relief, restoration of function, and patient satisfaction

PURPOSE: To compare the horizontal stability of the distal clavicle following arthroscopic resection of its lateral end by direct and indirect techniques. TYPE OF STUDY: Biomechanical test of cadaveric specimens. METHODS: We performed arthroscopic distal clavicle resection on 12 fresh-frozen human cadaveric shoulders using direct (group 1, n = 6) or indirect (group 2, n = 6) approaches. In both groups 5 mm of distal clavicle were resected using an arthroscopic burr. The specimens were mounted on a materials testing device that allowed translation of the clavicle along the anteroposterior axis. The degree of posterior translation was measured from maximum anterior displacement of the clavicle. RESULTS: Mean posterior translation was 19.4 mm (range, 18 to 23 mm; SD, 2.2) and 21.3 mm (range, 18 to 25 mm; SD, 3.1) for groups 1 and 2, respectively. This difference was not statistically significant ( P = .27). Conclusions: This study suggests that there is no significant difference in anteroposterior stability of the clavicle following arthroscopic distal clavicle resection with either a direct or indirect approach. CLINICAL RELEVANCE: Clinically, this study addresses concerns about increased potential instability associated with the indirect technique of distal clavicle resection. From a biomechanical standpoint, based on this study, there is no concern for increased instability with the indirect technique of distal clavicle resection compared to a direct technique

The simultaneous diagnosis of ipsilateral patellar tendon rupture and anterior cruciate ligament tear is rare. Surgical repair is complicated by different rehabilitation regimens as well as anterior cruciate ligament graft choices. We present a case where at the same operative setting, the patellar tendon was repaired, and the anterior cruciate ligament reconstructed with autologous hamstring graft

During exercise, muscular expansion and swelling occur. Chronic exertional compartment syndrome represents abnormally increased compartment pressures and pain in the involved extremity secondary to a noncompliant musculofascial compartment. Most commonly, it occurs in the lower leg, but has been reported in the thigh, foot, upper extremity, and erector spinae musculature. The diagnosis is obtained through a careful history and physical exam, reproduction of symptoms with exertion, and pre- and post-exercise muscle tissue compartment pressure recordings. It has been postulated that increased compartment pressures lead to transient ischemia and pain in the involved extremity. However; this is not universally accepted. Other than complete cessation of causative activities, nonoperative management of CECS is usually unsuccessful. Surgical release of the involved compartments is recommended for patients who wish to continue to exercise