Reproduction of Hip Offset and Leg Length in Navigated Total Hip Arthroplasty: How Accurate Are We?

This study assesses how accurately we can restore hip offset and leg length in navigated total hip arthroplasty (THA). 152 consecutive patients with navigated THA formed the study group. The contra-lateral hip formed control for measuring hip offset and leg length. All radiological measurements were made using Orthoview digital software. In the normal hip offset group, the mean is 75.73 (SD- 8.61). In the reconstructed hip offset group, the mean is 75.35 (SD - 7.48). 95.39% had hip offset within 6 mm of opposite side while 96.04% had leg length restored within 6 mm of contra-lateral side. Equivalence test revealed that the two groups of hip offsets were essentially the same. We conclude that computer navigation can successfully reproduce hip offset and leg length accurately.

Safety profile of sural nerve in posterolateral approach to the ankle joint: MRI study.

The posterolateral approach to ankle joint is well suited for ORIF of posterior malleolar fractures. There are no major neurovascular structures endangering this approach other than the sural nerve. The sural nerve is often used as an autologous peripheral nerve graft and provides sensation to the lateral aspect of the foot. The aim of this paper is to measure the precise distance of the sural nerve from surrounding soft tissue structures so as to enable safe placement of skin incision in posterolateral approach. This is a retrospective image review study involving 64 MRI scans. All measurements were made from Axial T1 slices. The key findings of the paper is the safety window for the sural nerve from the lateral border of tendoachilles (TA) is 7 mm, 1.3 cm and 2 cm at 3 cm above ankle joint, at the ankle joint and at the distal tip of fibula respectively. Our study demonstrates the close relationship of the nerve in relation to TA and fibula in terms of exact measurements. The safety margins established in this study should enable the surgeon in preventing endangerment of the sural nerve encountered in this approach.

How to Achieve an Accurate Anatomical Femoral Tunnel Technique in ACL Reconstruction in the Early Years of Your Consultancy? Femoral Offset Aimer Technique: Consistent and Reproducible Technique.

Femoral tunnel malposition is the most common reason for failure of primary anterior cruciate ligament reconstruction. There are several methods to identify the anatomical location of femoral footprint. Femoral offset aimer technique is one such technique which is easy to use and reliable. It is an ideal technique for junior and inexperienced surgeons to recreate the femoral tunnel in its anatomical footprint. The senior author (P.E.) has been using this technique for 30 consecutive cases in his first year of independent practice during his consultancy without any major intraoperative complications. The author describes this technique in this article with tips and tricks which will especially guide the junior and inexperienced surgeons to avoid running into intraoperative problems while drilling the femoral tunnel.

Leg length discrepancy in computer navigated total hip arthroplasty - how accurate are we?

INTRODUCTION: The success of total hip arthroplasty (THA) depends on the restoration of 2 important parameters - hip offset and leg length. Leg length discrepancy (LLD) after THA is associated with back pain, gait disorder, general patient dissatisfaction and aseptic loosening. Hence it is of utmost importance to minimise LLD. METHODS: This is a retrospective study where we compared the reproduction of leg lengths between navigated THA group (152 patients) and nonnavigated THA group (57 patients). The leg lengths were measured radiologically using Ranawat technique on AP pelvic radiograph. RESULTS: In the navigated group, the leg lengths of the reconstructed hips were restored to within 6 mm of the opposite leg in 146 patients (96.05%) while 6 patients (3.94%) had LLD of more than 6 mm. In the nonnavigated group, 29 patients (51%) had their leg lengths restored within 6 mm of the opposite leg while the remaining 28 patients (49%) had their LLD greater than 6 mm. Statistical analysis of the 2 pairs of LLD measurements (navigated hip and nonnavigated group) using Mann-Whitney U-test revealed significant difference between these two groups (p<0.001). CONCLUSIONS: Based on our results we conclude that computer navigation is an excellent tool to facilitate the successful reproduction of leg length in THA.