Satisfaction following total knee replacement (TKR) surgery remains suboptimal at around 80%. Prediction of factors influencing satisfaction may help manage expectations and thus improve satisfaction. We investigated preoperative variables that estimate the probability of achieving a successful surgical outcome following TKR in several outcomes important to patients. 9 pre-operative variables (easily obtained on initial consultation) of 591 unilateral TKRs were selected for univariant then multivariant analyses. These variables included Oxford Knee Score (OKS), age, sex, BMI, ASA score, pain score, mobility aids, SF12 PCS & SF12 MCS. Using the relative predictive strengths of these variables we modeled the probabilities a successful result would be achieved for 6 patient reported outcomes at 3 and 12 months following surgery. These were ‘Excellent/good OKS’, ‘Mild/no pain’, ‘Walking without/at first a limp’, ‘No/little interference with normal work’, ‘Kneeling with little/no difficulty’ and ‘Satisfaction with surgery’.Introduction & aims
Method
The risk of hip dislocation after revision total hip arthroplasty is up to 20% following surgery for periprosthetic fractures. A technique was developed by the senior authors, involving a transtrochanteric osteotomy and superior capsulotomy to attempt to minimise this risk(1). This prospective study examines a cohort of 40 patients undergoing this novel technique, which involves extending the fracture proximally to the tip of the greater trochanter. This is then extended into the soft tissues in the mid lateral plane as a split of the glutei and a minimally superior capsulotomy (preserving the anterior and posterior capsule). This allows for revision of the femoral component, and retention of the socket and liner. The outcomes of interest to the authors were dislocation rates, clinical outcome measured using the Oxford hip score. These were assessed along with X-ray imaging at 1, 2 and 5-year intervals to confirm fracture union and measure stem subsidence.Introduction
Methods
We identified 26 tibial tubercle osteotomies (TTOs) performed in 23 revision knee arthroplasties between 2009 and 2013. Average age at last operation was 66 (33–92). Mean follow-up period was 14 months (3–33). Eleven TTOs were performed in 10 knees for single stage revisions and 15 TTOs were performed in 13 knees for 2 stage revisions in the setting of deep infection. In this infected subset 11 patients had a TTO performed at the first stage. This osteotomy was left unfixed to avoid leaving metalwork in a potentially contaminated wound, reopened, and then definitively secured with screws at the second stage. Our technique involves fashioning a long 7×1cm tibial tuberosity osteotomy without a proximal step-cut. All osteotomies united with no fractures. Minor proximal migration was noted in one case associated with screw loosening. There was no proximal migration noted in the 2 stage cases where the osteotomy had been left initially unfixed. There were no extensor lags. We conclude that TTO is a safe and reproducible procedure when adequate exposure cannot be obtained in revision knee arthroplasty. In 2 stage revisions sequential osteotomies does not decrease union rates and leaving the osteotomy unfixed after the first stage does not cause any issues.
Eligible patients were randomly allocated to PMI or standard intramedullary jigs. Smith and Nephew's patient specific cutting blocks (Visionaire) were used for PMI. Postoperative component positioning was investigated using the ‘Perth CT protocol’. Deviation of more than 3° from the recommended position was regarded as an outlier. Exact Mann-Whitney U test was used to compare component positioning and difference in proportion of outliers was calculated using Chi Squared analysis. Fifty-five knees were enrolled in the standard instrumentation group and fifty-two knees in the PMI group. Coronal femoral alignment was 0.7 ± 1.9° (standard) vs 0.5 ± 1.6° (PMI) (P=0.33). Outliers 9.4% vs 7.4% (P=0.71). Coronal tibial alignment was 0.4 ± 1.5° (standard) vs 0.6 ± 1.4° (PMI) (P=0.56). Outliers 1.9% vs 1.9% (P=0.99). Sagittal femoral alignment was 0.6 ± 1.5° (standard) vs 1.3 ± 1.9° (PMI) (P=0.07). Outliers 3.8% vs 13.2% (P=0.09). Tibial slope was 1.7 ± 1.9 ° (standard) vs 1.8 ± 2.7° (PMI) (P=0.88). Outliers 13.2% vs 24.1% (P=0.15). External rotation of femoral component was 0.6 ± 1.4° (standard) vs 0.2 ± 1.8° (PMI) (P=0.14). Outliers: 3.8% vs 5.6% (P=0.66). Compared to standard intramedullary jigs, patient matched instrumentation does not improve component positioning or reduce alignment outliers.
