Faculty Bibliography

A fracture construct, representing a worst-case model of a comminuted intertrochanteric fracture, was created in order to compare the fixation stability of two different cephalomedullary nails: one where the lag screw can telescope within itself to achieve displacement of the head-neck fragment, and the other where the solid lag screw slides only. After nail fixation, the models were loaded and then cycled, and positions of the head-neck fragment and lag screw were determined. Both nails similarly acted to limit motion of the head-neck fragment by the sliding of their lag screws, causing impingement of the fragment against the nail. Fragment movement was achieved with significantly less force with the telescoping lag screws, which also showed no final lateral projection from the nail. This was in contrast to the solid lag screws that demonstrated lateral projection in all cases.

Hip resurfacing arthroplasty has been developed as an alternative to traditional total hip arthroplasty, in an effort to minimize the loss of native bone in young patients with symptomatic hip osteoarthritis. Femoral neck fracture following hip resurfacing is a unique complication; several risk factors are associated with this complication, including female gender. In the present study, we used finite element models of the proximal femur to simulate stresses across the femoral neck in pelvis models with varying widths. This analysis demonstrated an increase in hip reaction forces as the width of the pelvis increases, a condition that simulates a resurfacing condition in a female pelvis. This difference in peak stress on the femoral neck may explain the increased incidence of femoral neck fractures seen in female patients following hip resurfacing.

Orthopaedic patients with poor nutritional status are at an increased risk of postoperative complications, such as infection and wound healing. Nasal colonization with Staphylococcus aureus, especially with methicillin-resistant Staphylococcus aureus, has been shown to be a risk factor for surgical-site infections. We examined the incidence of nutritional depletion in our arthroplasty population and its correlation with Staphylococcus aureus colonization. We conducted a retrospective review of prospectively collected data of our arthroplasty patient population. Patients with known Staphylococcus aureus colonization or surgical-site infection were compared with a random cohort of patients. Patient demographics, preoperative nasal culture, and two nutritional screening scores were collected. Six hundred and fifty-two patients underwent arthroplasty and completed preoperative nasal cultures and nutritional assessment. A high percentage (27%) of our patients demonstrated some level of nutritional depletion prior to joint replacement. Overall nutritional scores were not significantly associated with surgery-type, preoperative nasal culture, or surgical- site infection in our patient population.

The diagnostic value of the vacuum phenomenon between the femoral head and the acetabulum, and time frame of its occurrence after application of traction is an important clinical question. The resulting arthrogram may outline the shape, location, and extent of cartilage lesions prior to arthroscopy of the hip joint. The presence, duration, and diagnostic information of the vacuum phenomenon were evaluated in 24 hips that underwent arthroscopy. The operative diagnosis was compared to the results of imaging studies and to findings obtained during a traction trial prior to arthroscopy. Indications for arthroscopy included avascular necrosis, labral tears, loose bodies, osteoarthrosis, and intractable hip pain. In 22 hips the vacuum phenomenon developed within 30 seconds after application of traction. The most important data obtained from the vacuum phenomenon was the location and extent of femoral head articular cartilage detachment and the presence of nonossified loose bodies. The vacuum phenomenon did not reveal labral or acetabular cartilage pathology in any of these patients. The vacuum phenomenon obtained during the trial of traction can add valuable information prior to hip arthroscopy. Femoral head articular cartilage detachment was best documented by this method. The hip arthroscopist should utilize this diagnostic window routinely prior to hip arthroscopy.

INTRODUCTION: Wrong-site surgery is defined as an operation conducted at the wrong site, on the wrong person, or resulting in the wrong procedure. Since 1993, more than 2200 wrong-site surgeries have been reported by the National Practitioner Data Base. A 2005 survey reported, 5.6% of replying academy fellows encountered a wrong-site surgery incident. Multiple interventions have been since suggested for prevention of these occurrences by the American Academy of Orthopaedic Surgeons and Joint Commission on Accreditation of Healthcare Organizations. MATERIALS AND METHODS: This institutional review board-approved study was conducted to investigate patient compliance and reliability in marking the surgical site. Two hundred patients undergoing orthopedic surgery who agreed to participate were enrolled at the time of preoperative testing and clearance for surgery. The patients received instructions to mark the surgical site with a 'YES.' Patient data collected included age, sex, procedure type and location, history of previous orthopedic surgeries, workmen's compensation status or motor vehicle collision involvement, employment status, primary language, level of education, presence of depression or toxic habits, and the time between enrollment and day of surgery. RESULTS: We achieved an overall compliance rate of 68.2%. There was no difference with respect to sex, tobacco use or history of depression, level of education or occupation, workmen's compensation, or government insurance status. The mean age of compliant patients was 48.6 years versus 53.3 years for those who did not comply (P = 0.05). About 72% of those who spoke English as a primary language complied, as opposed to 49% in others (P = 0.009). The time between enrollment and surgery was 10.4 days in compliant patients versus 23.1 days in noncompliant patients (P = 0.05). No statistically significant difference was noted with all other variables recorded. In no instance did patients mark the wrong side or make any marks likely to contribute to the wrong operation. CONCLUSIONS: Patient's ability to be involved in this preventative measure is independent of most demographic variables previously thought to be significant. However, in view of the 68.2% compliance, patient involvement in surgical site marking is unreliable and may not help in decreasing the chances of wrong-site surgery

BACKGROUND: Patellar tendinitis is one of the several differential diagnosis of anterior knee pain. The clinical diagnosis of patellar tendinitis is based on tenderness to palpation at the inferior pole of the patella. The tenderness has been noted to be maximal when the knee is extended and the quadriceps relaxed, but a definite clinical sign for diagnosis is lacking. The accuracy of two clinical signs was assesed by a two-stage study which included physical examination, MRI and a cadaveric study. MATERIALS AND METHODS: Two clinical signs, the "passive flexion-extension sign" and the "standing active quadriceps sign" were assessed in 10 consecutive patients with presumed patellar tendinitis. Five patients had an MRI, showed focal abnormality in the tendon. The location of the MRI finding corresponded, to the region of maximal tenderness. A cadaveric dissection was undertaken to describe the anatomy of the patella and the patellar tendon during these tests. RESULTS: Both tests showed a significant decrease in tenderness at the area of inflammation when the patellar tendon was under tension. The cadaveric dissection showed that when the knee is flexed to 90 degrees or when the quadriceps is tensioned the deep fibers of the tendon do not deform to anteriorly applied pressure. CONCLUSION: We suggest using these studies routinely in the evaluation of patients with anterior knee pain.

BACKGROUND: Methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus surgical site infections are an increasing health problem in the United States. To date, no study, as far as we know, has evaluated the prevalence of Staphylococcus aureus colonization in orthopaedic surgeons. The purpose of our study was to assess the prevalence of methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus colonization in orthopaedic surgery attending surgeons and residents at our institution compared with that in our high-risk patients. METHODS: We performed nasal swab cultures in seventy-four orthopaedic attending surgeons and sixty-one orthopaedic surgery residents at our institution, screening for methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus. We compared these results with a prospective database of nasal cultures of patients undergoing joint replacement and spine surgery. RESULTS: A total of 135 physicians were screened. Of those physicians, 1.5% were positive for methicillin-resistant Staphylococcus aureus and 35.7% were positive for methicillin-sensitive Staphylococcus aureus. None of the sixty-one residents were positive for methicillin-resistant Staphylococcus aureus. However, 59% were positive for methicillin-sensitive Staphylococcus aureus. Of the seventy-four attending surgeons, 2.7% were positive for methicillin-resistant Staphylococcus aureus and 23.3%, for methicillin-sensitive Staphylococcus aureus. Previous studies at our institution have demonstrated a 2.17% prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus and an 18% rate of methicillin-sensitive Staphylococcus aureus in high-risk patients. Thus, no difference was found between the prevalence of methicillin-resistant Staphylococcus aureus in residents or attending surgeons and that in the high-risk patients. However, the prevalence of methicillin-sensitive Staphylococcus aureus colonization in the surgeons (35.7%) was significantly higher than that in the high-risk patient group (18%) (p < 0.01). CONCLUSIONS: At a major teaching hospital, a higher prevalence of methicillin-sensitive Staphylococcus aureus colonization was found among attending and resident orthopaedic surgeons compared with a high-risk patient group, but the prevalence of methicillin-resistant Staphylococcus aureus colonization was similar

STUDY DESIGN: Retrospective study of patients enrolled in a prospective randomized Food and Drug Administration trial with single level cervical disc replacement (CDR) with the ProDisc-C (Synthes, Paoli, PA). OBJECTIVE: Evaluate the segmental range of motion (ROM) in the cervical spine pre- and postoperative after CDR. SUMMARY OF BACKGROUND INFORMATION: Each cervical level is believed to have its own biomechanical characteristics, ultimately leading to different sagittal and lateral ROM. Our understanding of the factors that influence motion after CDR continues to change and expand. METHODS: One hundred sixty-four patients with single level ProDisc-C arthroplasty were evaluated radiographically using Medical Metrics (QMATM, Medical Metrics, Inc., Houston, TX). Pre- and postoperative disc height and ROM were measured from standing lateral and flexion-extension radiographs. Of these 164 patients, 44 had a CDR at C6/C7, 96 at C5/C6, 18 at C4/C5, and 6 at C3/C4. The mean follow-up was of 24 months. Statistical analysis evaluated the difference in mean ROM between the groups. RESULTS: Before surgery, C4/C5 had more sagittal ROM compared with C3/C4, C5/C6, and C6/C7 (P < 0.001.) Before surgery, C4/C5 also had more lateral ROM compared with C3/C4, C5/C6, and C6/C7 (P = 0.015). After surgery, there were no significant differences in sagittal and lateral ROM between C3/C4, C4/C5, C5/C6, and C6/C7. The delta (difference between pre- and postoperative) proved that the C4/C5 CDR actually lost sagittal ROM (-2.5 degrees ) compared with the other levels, which gained sagittal ROM, C3/C4 (0.9 degrees ), C5/C6 (1.8 degrees ), and C6/C7 (1.6 degrees ); P = 0.037. There was no significant difference in the delta lateral ROM between the segments: C3/C4, C4/C5, C5/C6, and C6/C7. CONCLUSION: CDR approximates the different segmental sagittal and lateral ROM. Although C4/C5 had negative delta ROM in the sagittal and lateral planes, it provided a satisfactory final ROM. Long-term clinical outcome studies are needed to properly evaluate if these differences could ultimately affect the patients everyday life

STUDY DESIGN: Retrospective case-control review. OBJECTIVE: This retrospective study explored the hypothesis that the perioperative administration of blood products is an identifiable risk factor of increased surgical site infections (SSIs) after thoracic and lumbar spine surgical procedures. SUMMARY OF BACKGROUND DATA: Surgical site infections are a significant cause of postoperative morbidity and mortality. According to the Center for Disease Control's National Nosocomial Infections Surveillance system, which monitors the rate of hospital-acquired infections in the United States, SSIs represent the third most commonly reported type of nosocomial infection, accounting for 14% to 16% of all nosocomial infections. The incidence of SSIs after spinal surgery is influenced by both preoperative and intraoperative risk factors. The relationship between blood products and SSIs has been a matter of debate for more than 2 decades. Several studies have supported the association between the use of blood products and the development of postoperative surgical site infections. METHODS: A retrospective case-control study was performed. We reviewed the charts of all patients who had undergone thoracic and/or lumbar spinal surgery at the NYU Hospital for Joint Diseases between 2002 and 2007. All patients who had developed surgical site infections following spine surgery in this 5-year period were identified. RESULTS: Data for 61 cases and 71 controls were included in this study. The analysis of the preoperative risk factors was performed for the entire population of patients. Body mass index and blood transfusions were found to be statistically significant risk factors for increased surgical site infections for this population. CONCLUSION: Our findings support current theories that blood transfusions may have modulatory effects on the immune system of the recipients. Our specific study in spine patients may contribute to the expanding literature on allogeneic blood transfusions and the risk of nosocomial infections and encourage surgeons to favor a more restrictive policy with regard to transfusions

Background: When challenged with extremity wounds that require further debridement, edema reduction and decreased bacterial content, temporarily implanting vacuum-assisted closure reticulated open-cell foam dressings is an effective adjunct for temporary wound closure and results in enhanced flap tissue survival. Methods: A retrospective review was performed in 13 consecutive patients with a lower extremity surgical wound and exposed hardware, joint, tendon or bone who received the two-stage wound closure treatment. Primary endpoints included time to closure, total wound duration, and wound closure status upon discharge. Results: Mean time from the initial procedure until definitive closure was 4 days (range, 2-8 days). Mean wound duration before the procedure was 54 days (range, 5-120 days). All 13 wounds had delayed primary closure or random pattern flap upon discharge and remained closed throughout the length of follow-up. Conclusions: Temporarily implanted vacuum-assisted closure may be a safe and effective adjunctive therapy when applied to the undersurface of newly developed flaps