Hyperflexion and Femoral Interference Screw Insertion in ACL Reconstruction

Background: In anatomic anterior cruciate ligament (ACL) reconstructions produced with flexible reamers and no knee hyperflexion, it is unknown whether knee hyperflexion is necessary for femoral interference screw insertion. Purpose: To compare femoral screw-graft divergence in anatomic ACL reconstructions with endoscopic interference screws placed without knee hyperflexion and with the use of flexible versus rigid screwdrivers. Study Design: Controlled laboratory study. Methods: Ten matched pairs of cadaveric knees had bone-tendon-bone graft ACL reconstructions with anatomic femoral tunnels. The knees were flexed to 90°. Femoral interference screws (7 × 20 mm) were placed in pairs of knees: in 1 knee with a flexible screwdriver and in the opposite knee with a rigid screwdriver. Graft-screw divergence was imaged with computed tomography scans and tested with cyclic and static biomechanical tests. Results: The mean screw-graft divergence was 12.07° ± 4.04° with the rigid screwdriver and 10.68° ± 3.23° with the flexible screwdriver ( P = .35). The cyclic tests with screws placed by a rigid screwdriver had a mean increase in displacement of 0.56 ± 0.20 mm. For screws placed with the flexible screwdriver, the mean increase in displacement was 0.58 ± 0.32 mm ( P = .66). Yield load was 393.3 ± 95.1 N for screws placed by a rigid screwdriver and 408.2 ± 119.0 N for screws inserted with the flexible screwdriver ( P = .78). Maximum load was 523.1 ± 88.7 N for screws placed by a rigid screwdriver and 467.1 ± 107.3 N for screws inserted with the flexible screwdriver ( P = .09). Conclusion: With either a rigid or a flexible screwdriver, there were no significant effects on screw divergence or fixation strength. Clinical Relevance: Knees can be kept at 90° during endoscopic femoral interference screw insertion. The use of a traditional rigid or flexible screwdriver will not affect screw-graft divergence or fixation strength.

Arthroscopic Reconstruction of the Anterior Cruciate Ligament Using Bone-Patellar Tendon-Bone Autograft: Experience of the First 100 Cases

Purpose. To review the results of patients who underwent arthroscopic reconstruction of the anterior cruciate ligament (ACL) via a single incision technique using a bone-patellar tendon-bone autograft. Methods. Patients with ACL-deficient knees who were symptomatic and wanted to maintain an active lifestyle or continue sporting activities were included. ACL reconstruction using the bone-patellar tendon-bone graft was performed on 100 patients. One-year follow-up was completed in 78 patients who were then reviewed. The mean age of patients reviewed was 26.8 years (range, 21–39 years), of whom 35 (44.9%) were aged between 26 and 30 years. There were 73 men and 5 women (ratio, 14.6:1). Injuries on the right side outnumbered those on the left (44 versus 34). Sports injuries accounted for 66.7% (n=52) of patients, motor vehicle accidents and household injuries accounted for 30.8% (n=24) and 2.6% (n=2), respectively. Results. Excellent and good-to-excellent results were achieved in 7 (9%) and 61 (78.2%) of patients. Residual anterior knee pain (n=18) was the most common complication, followed by difficulty in regaining full range of motion (n=10) and divergence of femoral screw (n=9). Conclusion. This procedure provides consistent and reproducible results in carefully selected patients and allows them an early return to sporting activities with minimal residual morbidity.

Polymethylmethacrylate Venogram after Cemented Arthroplasty of the Hip. A Report of Seven Cases and Review of the Literature

We present seven patients with polymethylmethacrylate (PMMA) filling the veins accompanying the second perforating branch of the profunda femoris artery detected after primary cemented hip arthroplasty. All implants were cemented utilizing retrograde canal filling with a cement pistol and pressurization. No haemodynamic changes were observed throughout any of the procedures and all patients had an uneventful recovery and evolution. The presence of a PMMA venogram is an infrequent finding after cemented hip arthroplasty. In our seven cases it was not associated with higher peri-operative morbidity. Differential diagnoses must be made with cement extruded through incomplete fractures or through femoral screw holes, as treatment and weightbearing status may differ.

THE USE OF FINITE ELEMENT METHOD TO ADDRESS PROXIMAL MIGRATION OF FEMORAL NECK FRACTURE FIXATION DEVICES IN THE ELDERLY

Falls among the elderly are a common occurrence and the incidence rate is increasing with our aging population. In such a population, a fall may precipitate a femoral neck fracture which may be treated by any one of a variety of femoral screw/plate mechanisms. Unfortunately, such mechanisms can fail in service as the device migrates proximally eventually requiring a secondary and more invasive surgery. In the current study we propose a new design to address this failure mechanism and we use a simple finite element model to study a modification to the current design.