Intraoperative computer navigation parameters are poor predictors of function 1 year after total knee arthroplasty.

Intraoperative navigation data were collected prospectively for 134 knees undergoing cemented, posterior-stabilized total knee arthroplasty. Partial least squares regression analysis was used to test the association between patient demographics and intraoperative data collected with a computer-assisted navigation system (coronal alignment, ligament balance, range of motion, external tibiofemoral rotation) with 1-year outcomes (36-item Short-Form Health Survey, Oxford Knee Score, range of motion). Age at surgery displayed the largest coefficients of any other predictor. In contrast, navigation coefficients were variable in the strength and direction of their association with the outcome variables. Static knee alignment data obtained intraoperatively have limited capacity to explain the variance in functional outcome at 1 year. Although alignment and component position can be precisely measured intraoperatively, intrinsic patient factors remain dominant in determining the outcome.

Is femoral nerve block necessary during total knee arthroplasty?: a randomized controlled trial.

There remains a lack of randomized controlled trials comparing methods of perioperative analgesia for total knee arthroplasty. To address this deficiency, a blinded, randomized controlled trial was conducted to compare the use of femoral nerve block (group F) and local anesthetic (group L). A sample of 55 patients who met the inclusion criteria were randomized to either group. No significant differences in the most severe pain score or 36-Item Short Form Health Survey, The Western Ontario and McMaster Universities Arthritis Index (WOMAC), or Oxford scores were observed between groups. However, the Knee Society score was significantly higher in group F. In addition, group F used significantly fewer micrograms of intravenous fentanyl in the first 24 hours. Balancing the risks of femoral nerve block with those of increased systemic narcotic delivery should be performed on a case-by-case basis.

Thromboembolic events are uncommon after open treatment of proximal humerus fractures using aspirin and compression devices.

BACKGROUND: Thromboembolic phenomena have long been recognized as a major cause of morbidity and mortality in hospitalized patients, especially those undergoing reconstructive surgery. We have been empirically treating patients with aspirin, early ambulation, and mechanoprophylaxis after operative management of proximal humerus fractures. However, we have not established the incidence of postoperative deep vein thrombosis and pulmonary embolism in this population. QUESTIONS/PURPOSES: We determined the incidence of deep vein thrombosis and pulmonary embolism in patients having surgery for displaced proximal humerus fractures treated with our thromboprophylactic regimen. PATIENTS AND METHODS: We prospectively followed 50 patients with proximal humerus fractures who underwent fixation with plate osteosynthesis (n = 40) or hemiarthroplasty (n = 10) between August 2005 and December 2008. Deep vein thrombosis prophylaxis consisted of oral enteric-coated aspirin, pneumatic calf compression pumps, and early ambulation in all patients unless medically contraindicated. Color-flow Doppler ultrasound of the affected arm and both lower extremities was performed at a mean of 14 days (range, 7-21 days) postoperatively to evaluate for deep vein thrombosis. All patients clinically suspected to have suffered a pulmonary embolism underwent a CT angiogram. RESULTS: We identified no patients with deep vein thrombosis or pulmonary embolism in this population. CONCLUSIONS: Deep vein thrombosis and pulmonary embolism are not uncommon after major reconstructive surgery about the shoulder in untreated patients. Our data suggest these events can be low after surgery for proximal humerus fractures followed by a thromboprophylactic regimen including aspirin, mechanical devices, and early mobilization. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Extra-articular technique for semiextended tibial nailing.

Intramedullary nailing is a widely accepted technique for the stabilization of unstable diaphyseal tibia fractures. When this method of stabilization is applied to proximal and distal metadiaphyseal fractures, achieving and maintaining fracture reduction is more difficult. The intramedullary nailing of proximal metadiaphyseal fractures in semiextension has been advocated to make stabilization less difficult. The intra-articular nature of this technique makes it less appealing. We present a nailing technique that facilitates extra-articular semiextended tibial nailing. The technique simplifies intraoperative imaging, fracture reduction, and maintenance of reduction during nail insertion and locking.

Bicipital groove morphology on MRI has no correlation to intra-articular biceps tendon pathology.

BACKGROUND: Multiple authors have debated the contribution of intertubercular groove morphology to biceps tendon pathology. It has been proposed that the shallow groove, combined with the supertubercular ridge of Meyer, predisposes patients to bicipital disease. In this study we hypothesized that there would be a correlation between bicipital groove morphology and the intraoperative finding of biceps pathology. METHODS: Seventy-five consecutive patients (average age of 63) undergoing arthroscopic rotator cuff repair surgery had their biceps tendons and intertubercular groove morphologies prospectively evaluated on closed MRI T1 axial cut images. The opening angle and medial wall angle of the bicipital groove was measured for each patient. At the time of surgery, the biceps tendon was classified as normal, inflamed, partially ruptured, or ruptured and the findings correlated to the bicipital groove measurements. RESULTS: The average opening angle was 81 degrees for normal biceps tendons and 77 degrees for torn biceps tendons. The average medial wall angle was 47 degrees for normal biceps tendons and 49 degrees for torn biceps tendons. Using Chi-square analysis, we found no statistically significant correlation between the bicipital groove average opening angle and medial wall angle on MRI and intraoperative biceps tendon pathology. CONCLUSION: This study does not support any correlation between intraarticular biceps tendon pathology and bicipital groove morphology.

Treatment of distal biceps tendon ruptures.

Distal biceps tendon rupture is an injury typically reported in the dominant extremity of middle-aged men. Clinical findings are the mainstay of diagnosis, but magnetic resonance imaging or ultrasound imaging can provide additional diagnostic information. Anterior 1- or 2-incision repairs are commonly used. Various fixation techniques have been reported, all with comparable biomechanical results and clinical outcomes. Complication rates are lower in patients treated closer to time of injury. Tendon retraction associated with chronic ruptures can present a difficult surgical problem. Advanced soft-tissue imaging adds helpful information about the level of biceps tendon retraction and possible reparability. When the tendon can be reapproximated safely at less than 45 degrees to 90 degrees of elbow flexion, then primary repair may be performed. When reapproximation is not possible, options are reconstruction and tenodesis. Reconstruction performed through 1 or 2 incisions with either allograft or autograft has successfully restored both motion and power.

Initial stability of the acetabular fragment after periacetabular osteotomy: a biomechanical study.

BACKGROUND: Periacetabular osteotomy (PAO) has become the treatment of choice for skeletally mature patients with symptomatic acetabular dysplasia. Coincident with increasing use of PAO worldwide has been the introduction of various techniques for fixation of the acetabular fragment. Owing to the expanding indications for PAO, such as acetabular retroversion and femoroacetabular impingement, there is an increased interest in biomechanical data supporting the use of the varied acetabular fragment fixation techniques. Our study investigated the biomechanical strength of several PAO fixation techniques in vitro, including a novel plating technique. METHODS: PAO was performed on 17 artificial hemi-pelves with standardized biomechanical properties. Specimens were instrumented with the following constructs-3 screws from the iliac crest into the fragment (IS), 3 screws from the iliac crest and 1 transverse screw from the anterior inferior iliac spine into the sciatic buttress (IT), or 1 transverse screw with a contoured 3-hole plate across the iliac osteotomy (PT). The specimens were then loaded cyclically under compression and tension and to failure under tension in an material testing system through the anterior-inferior iliac spine. RESULTS: Data analysis with a single factor analysis of variance yielded mean loads-to-failure of 462 N for IS, 714 N for IT, and 817 N for PT (P=0.005). Further analysis using 2-sample t tests revealed that both IT and PT provided significantly higher loads-to-failure than IS (P=0.016 and P=0.0007, respectively). Under cyclic compression loading, the IT construct demonstrated decreased overall displacement when compared with IS (P=0.003). Under cyclic tension loading, PT achieved significantly smaller overall displacement than IS (P=0.007), as did IT when compared with IS (P=0.018). However, no significant difference was found between PT and IT (P=0.165) groups in cyclic loading or failure testing. CONCLUSIONS: Prior results showing improved performance of the IT construct have been replicated in a novel tension model. The novel plating technique provides greater load-to-failure than IS and is not inferior to IT. Both PT and IT allow significantly less displacement than IS in tensile and compressive cyclic loading. This novel technique may be easier to perform by surgeons in training or those new to the procedure. The results suggest a move beyond fixation solely with 3 antegrade screws. LEVEL OF EVIDENCE: Biomechanical study.

Anatomy of the coronoid process.

PURPOSE: Coronoid injuries are classified according to the size of the coronoid fracture. The purpose of this study was to provide a detailed anatomic description of the coronoid process, with specific focus on the coronoid height, the coronoid width, and the olecranon-coronoid angle. METHODS: Thirty-five cadaveric arms were dissected. All soft tissue was removed and the ulna was disarticulated from the humerus, radius, and the carpal bones. A 3-dimensional digitizing system was used to locate 19 anatomic landmarks on each specimen. By using the 3-dimensional coordinates of the landmarks, the coronoid heights, proximal ulnar widths, and olecranon-coronoid angles were determined. RESULTS: The coronoid height, with its base defined by the trough of the trochlear notch and the slope change of the distal coronoid process, measured 15 mm and was 42% of the ulnar height. The coronoid height, with its base defined by the transverse groove of the sigmoid notch at the guiding ridge and the distal insertion of the brachialis muscle, measured 15 mm and was 43% of the ulnar height. The olecranon-coronoid angle ranged between 33 degrees and 38 degrees . CONCLUSIONS: For lateral radiographic classification of coronoid fractures, coronoid height is best defined by the trough of the trochlear notch and the slope change of the distal coronoid process. For anatomic studies, coronoid height is best defined by the transverse groove of the sigmoid notch at the guiding ridge and the distal insertion of the brachialis muscle. The olecranon-coronoid angle is best defined by the angle formed by the lines from the olecranon tip through the coronoid tip and through the slope change of the distal coronoid process. The coronoid anatomy measurements reported in this study may help to improve coronoid fracture classification.