Does a combined screw and dowel construct improve tibial fixation during anterior cruciate ligament reconstruction?

PURPOSE: The aims of the present study were to compare the biomechanical properties of tibial fixation in hamstring-graft ACL reconstruction using interference screw and a novel combination interference screw and dowel construct. MATERIAL AND METHODS: We compared the fixation of 30 (2- and 4-stranded gracilis and semitendinosis tendons) in 15 fresh-frozen porcine tibiae with a biocomposite resorbable interference screw (Group 1) and a screw and dowel construct (Group 2). Each graft was subjected to load-to-failure testing (50 mm/min) to determine maximum load, displacement at failure and pullout strength. RESULTS: There were no significant differences between the biomechanical properties of the constructs. Multivariate analysis demonstrated that combination constructs (ß = 140.20, p = 0.043), screw diameter (ß = 185, p = 0.006) and 4-strand grafts (ß = 51, p = 0.050) were associated with a significant increase in load at failure. Larger screw diameter was associated with increased construct stiffness (ß = 20.15, p = 0.020). CONCLUSION: The screw and dowel construct led to significantly increased fixation properties compared to interference screws alone in a porcine model. Increased screw diameter and utilization of 4-strand ACL grafts also led to improvement in load-to-failure of the construct. However, this is an in vitro study and additional investigations are needed to determine whether the results are reproducible in vivo. LEVEL OF EVIDENCE: Level V; Biomechanical study.

Evaluation of the accuracy of patient-specific cutting blocks for total knee arthroplasty: a meta-analysis.

PURPOSE: Because published studies on the accuracy achieved with patient-specific guides during total knee arthroplasty (TKA) contradict each other, this systematic review and meta-analysis sought to compare radiological TKA outcomes when patient-specific cutting blocks (PSCB) were used to the outcomes when standard manual instrumentation was used. METHODS: The meta-analysis was implemented according to PRISMA Statement Criteria. The primary endpoint was the hip-knee-ankle (HKA) angle, which represents the leg's mechanical axis. The accuracy of component placement in the coronal and sagittal planes, and the accuracy of femoral component rotation were also compiled. After testing for publication bias and heterogeneity across studies, data were aggregated random-effects modeling when necessary. RESULTS: Fifteen articles were included: 916 total knee arthroplasty cases in the PSCB group and 998 in the MI group. The mechanical axis did not differ between the two groups (weighted mean difference 0.07°; 95 % CI, -0.5° to 0.65°; p = 0.8). Risk ratio analysis revealed no protective effect of using PSCB relative to the appearance of HKA angle outliers (RR = 0.88; 95 % CI, 0.68-1.13; p = 0.3). There was a trend towards a protective effect with PSCB for the risk of femoral component outliers, but the opposite was observed for the tibial component. The implantation procedure was stopped in 30 cases because the surgeon-authors found excessive discrepancies between the intra-operative observations and the pre-operative plan. CONCLUSIONS: This meta-analysis found no evidence that using patient-specific cutting blocks provides superior accuracy to using manual instrumentation during TKA.

How to Test the Anterolateral Ligament With Ultrasound.

Ultrasonography (US) is a nonirradiating, low-cost, real-time imaging modality that has very good spatial resolution. US can be used to view the anterolateral ligament (ALL) and injuries to the ALL. Several authors have sought to analyze the anterolateral aspect of the knee using US with varying luck. All of them analyzed the ALL statically only. The goal of this Technical Note is to describe in detail the technique that we use to analyze the anterolateral aspect of the knee in patients with an anterior cruciate ligament tear. We use a simple technique that starts by locating the tibial end of the ALL. The lateral inferior genicular artery is a reliable landmark in this context. The analysis is dynamic in addition to being static. To determine if the ALL is injured, we look for a lack of tension on the ALL when the knee is internally rotated and for a Segond fracture. We believe that it is essential to start evaluating the ALL by its tibial end. US analysis of the ALL forms the basis for developing an appropriate "à la carte" treatment for the patient's injury.

Fixation of a fractured femoral head through a medial hip approach: an original approach to the femoral head.

The decision to treat a femoral head fracture conservatively or surgically is the subject of ongoing debate. Several surgical approaches have been proposed for the open reduction and internal fixation of femoral head fractures. To our knowledge, fixation through a minimally invasive medial approach has not been described until now. The novel medial hip approach passes between the adductor muscle bellies posteriorly and their aponeuroses anteriorly. It provides direct access to the fracture site and allows for fixation by compression, without needing to dislocate the hip or detach the muscles. Any loose bodies in the joint that cannot be fixed can also be removed during the procedure. These features make the medial hip approach a clinically-relevant treatment option for the surgical management of femoral head fractures.