Short cementless femoral stems are increasingly popular as they allow for less dissection for insertion. Use of such stems with the anterior approach (AA) may be associated with considerable per-operative fracture risk. This study's primary aim was to evaluate whether patient-specific femoral- and pelvic- morphology and surgical technique, influence per-operative fracture risk. In doing so, we aimed to describe important anatomical thresholds alerting surgeons.

This is a single-centre, multi-surgeon retrospective, case-control matched study. Of 1145 primary THAs with a short, cementless stem inserted via the AA, 39 periprosthetic fractures (3.4%) were identified. These were matched for factors known to increase fracture risk (age, gender, BMI, side, Dorr classification, stem offset and indication for surgery) with 78 THAs that did not sustain a fracture. Radiographic analysis was performed using validated software to measure femoral- (canal flare index [CFI], morphological cortical index [MCI], calcar-calcar ratio [CCR]) and pelvic- (Ilium-ischial ratio [IIR], ilium overhang, and ASIS to greater trochanter distance) morphologies and surgical technique (% canal fill). Multivariate and Receiver-Operator Curve (ROC) analysis was performed to identify predictors of fracture.

Femoral factors that differed included CFI (3.7±0.6 vs 2.9±0.4, p<0.001) and CCR (0.5±0.1 vs 0.4±0.1, p=0.006). The mean IIR was higher in fracture cases (3.3±0.6 vs 3.0±0.5, p<0.001). % Canal fill was reduced in fracture cases (82.8±7.6 vs 86.7±6.8, p=0.007). Multivariate analysis and ROC analyses revealed a threshold CFI of 3.17 was predictive of fracture (sensitivity:84.6% / specificity:75.6%). Fracture risk was 29 times higher when patients had CFI>3.17 and II ratio>3 (OR:29.2 95%CI: 9.5–89.9, p<0.001).

Patient-specific anatomical parameters are important predictors of fracture-risk. When considering the use of short stems via the AA, careful radiographic analysis would help identify those at risk in order to consider alternative stem options.

Objectives

Alarm over the reported high failure rates for metal-on-metal (MoM) hip implants as well as their potential for locally aggressive Adverse Reactions to Metal Debris (ARMDs) has prompted government agencies, internationally, to recommend the monitoring of patients with MoM hip implants. Some have advised that a blood ion level >7 µg/L indicates potential for ARMDs. We report a systematic review and meta-analysis of the performance of metal ion testing for ARMDs.

Purpose

Use of a large femoral head metal-on-metal bearing in total hip arthroplasty may offer an advantage in terms of dislocation rates and more natural joint kinematics. The acetabular component is more rigid however in these prostheses and if not placed accurately can lead to increased levels of metal ion release. A prospective randomized controlled trial was conducted to quantify bone mineral density on the acetabular side, as well as compare metal ion levels from a standard metal-on-polyethylene bearing to a large head metal-on-metal bearing in primary total hip arthroplasty.

Purpose: Multi-modal therapy remains the cornerstone of post-operative pain management following knee replacement surgery. Femoral nerve catheters and blocks have been used with success in the management of post-operative pain yet most practicing arthroplasty surgeons and anaesthesiologists are unaware of the potential complications and risks of the procedure. The purpose of this study is to report on the complications associated with these techniques following knee replacement surgery.

Method: One thousand one hundred and ninety patients underwent knee replacement surgery between January 2004 and July 1, 2007 and received an indwelling continuous infusion femoral catheter for post-operative marcaine pump infusion. For the initial 469 patients (Group 1), the continuous infusion ran for 2 to 3 days. In 721 patients, the continuous infusion was discontinued 12 hours following surgery (Group 2).

Results: There were 15 major complications observed in 1190 patients: 7 femoral nerve palsies (2 in Group 1, 5 in Group 2) and 8 falls (4 in each group). For the patients who had fallen in hospital, the injuries sustained were: traumatic hemarthrosis, hemarthrosis requiring arthrotomy, major wound dehiscence with exposed implants, complete medial collateral ligament rupture requiring repair, quadriceps tendon rupture requiring delayed repair, minor wound dehiscence with suture, and displaced ankle fracture.

Conclusion: Femoral nerve catheters and blocks are effective tools for post-operative pain relief following knee arthroplasty surgery. However, it is important for the surgeon and anaesthesiologist to provide information regarding the potential complications of the treatment as part of an informed consent. Although the complication rate is relatively low at 1.3%, the occurrence of femoral nerve palsies as well as re-operations significantly delayed patient recovery. We did not observe a benefit in terms relative risk reduction with discontinuation of the continuous infusion 12 hours following surgery. The femoral palsies reported in our series have led our institution to adopt ultrasound guidance for catheter placement rather than tradition nerve stimulation technique, although the safety of this newer technique is currently under evaluation.