The medial parapatellar approach in total knee arthroplasty is arguably the most common approach, but the subvastus approach is less insulting to the quadriceps mechanism. A single centre, randomized controlled trial was conducted in a metropolitan hospital to investigate whether the subvastus approach afforded better outcomes than the medial parapatellar approach. Ninety participants with knee osteoarthritis were randomized to either the subvastus or medial parapatellar approach. The primary outcome was the American Knee Society Score and secondary outcomes reported included pain, extension and flexion range of motion, quadriceps lag, girth, Oxford Knee Score, 3 meter timed up and go test, days to straight leg raise, surgeon perceived difficulty, operation duration, tourniquet duration and length of stay. Data were collected preoperatively, intra-operatively, days 1,2,3, discharge, 6 weeks and 6, 12 and 18 months post operatively. Analysis was undertaken on 76 participants revealing no significant difference with the primary outcome (p=0.076; MP 167.3±36.6; SV 153.1±36.6) or any other outcome except for surgeon perceived difficulty, which favored the medial parapatellar approach (p=0.001; MP 3.3/10±1.9; SV 5.4/10±2.3) and days to straight leg raise, which favoured the subvastus approach by 0.9 days (p=0.044; MP 2.8±1.9; SV 1.9±1.6). The subvastus approach is technically more difficulty and offers no clinical benefit over the medial parapatellar approach.
The aim of this study was to assess the risks and benefits of mini-incision TKR. The limited exposure afforded by the small skin incision in the new technique of mini-incision TKR has the potential for increasing the risk of mal-positioning of components. Minor mal-positioning of components has the potential to increase polyethylene wear and may lead to early loosening and poor functioning of the TKR. The literature supports the concept that alignment within +/- 3 degrees of neutral mechanical alignment in the coronal plane is associated with a better outcome. If the mechanical axis falls outside this range it may have up to a 30% failure rate at 10 years. We report the results of 166 mini-incision TKR that have been undertaken in 154 patients (96F; 58M; mean age 72; mean BMI 29; 96% OA) since November 2003. The pre-operative mechanical axis ranged from 8 degrees valgus to 15 degrees varus. Surgery was undertaken with a precise skin incision and a midvastus split approach. Specialised cutting blocks were used to facilitate a smaller incision. The prosthesis inserted was a cemented Zimmer NexGen TKR of either posterior stabilised or cruciate retaining form. Long leg weight bearing alignment radiographs were available in 52% of patients. The mechanical axis was measured in the coronal plane and found to lie within +/- 3 degrees of neutral in 86% of patients. This compares favourably with the current literature which reports the mechanical axis falling within this range in between 72% and 85% of cases. We believe the mini-incision TKR is a safe, reliable and reproducible technique offering substantial savings to the patient and health service without compromising accuracy.
Metal on metal hip resurfacing is increasing in popularity for the young, active patient. We present the results of a consecutive series from a single surgeon over a ten year period; 295 hip resurfacings (McMinn and Cormet; Corin, Cirencester, UK) with a minimum follow up of 2 years and a mean follow up of 4 years. There were 173 males with a mean age of 53.4 years and 121 females with a mean age of 50.3 years. Forty-six patients underwent bilateral resurfacings. All resurfacings were performed through a posterior approach. The aetiology in this group was primary OA in 75.9%, inflammatory arthritis in 6.1%, DDH in 6.1%, AVN in 4.7%, trauma in 4.7%, Perthes in 1.7% and SUFE in 0.7%. Patients were reviewed clinically and radiographically on an annual basis. Follow-up was available on 93% of patients. 94.2% of hips have survived and the mean Harris Hip Score is 87.5. Females had a higher failure rate (10.7%) than males (2.3%). There was no clear trend between patient age and failure rate. The highest failure rate (33.3%) was seen in patients with DDH whilst only 4.5% of patients with OA failed. One patient with AVN failed but no failures occurred in patients with inflammatory arthritis, trauma, Perthes or SUFE. Failures occurred due to cup loosening (2.0%), neck fractures (1.7%), head loosening (1.0%), head collapse (0.3%), infection (0.3%) and pain (0.3%). The five patients who suffered neck fractures were symptomatic within 3 months of surgery. We remain cautiously optimistic about the medium term results of hip resurfacing. Careful patient selection is important and caution should be taken in females and patients with DDH
The aim of this paper is to evaluate the Linvatec SE graft tensioner system in obtaining predictable initial tension during ACL reconstruction using hamstring grafts. The gracilis and semitendinosus grafts were tensioned individually prior to fixation distally to a combined tension of 80N. The knees were then cycled through full range of motion and the tension recorded at 90 degrees and in full flexion and extension. Experience on the first 22 patients indicated that 41% required 10 cycles of the knee to remove pre-conditioning and equalise tension at 80N combined, while the remaining 50% required 15 cycles. 90% reached stable tension after 15 cycles. In 54% the tension increased at full extension and graft tension was adjusted to 80N in extension to avoid overconstraining the graft. Twenty-two patients studied following this initial protocol underwent outcome assessment after minimum 6 months. Mean KT1000 arthrometry manual maximum side to side difference was 1.5mm. Femoral fixation was achieved using the Endobutton (Smith and Nephew) and Tibial fixation using the Extralok bioabsorbable screw (Linvatec). A subsequent shortened protocol of initial over-tensioning to 60N and 40N for the semitendinosus and gracilis double bundles respectively, followed by 15 cycles of the knee resulted in stable 80N combined tension with no further drop with more cycling. We conclude that the new tensioner system allows for accurate and predictable initial tension of hamstring reconstructed ACL grafts and that its use can be simplified by using the second technique protocol.
We report serum metal ion level data in patients with unilateral and bilateral hip resurfacing over a ten-year period. In these patients there is an increase in both cobalt and chromium levels above the accepted reference ranges during the first 18 months after operation. Metal ion levels remain elevated, but decline slowly for up to five years. However, the levels then appear to start rising again in some patients up to the ten-year mark. There was no significant difference in cobalt or chromium levels between men and women. These findings appear to differ from much of the current literature. The clinical significance of a raised metal ion level remains under investigation.
