Abstract
The aim of this study was to determine prospectively whether a lateral capsular approach to the knee joint for the purposes of total knee arthroplasty confers any advantage over the traditional medial capsular approach.
One hundred consecutive valgus osteoarthritic knees with greater than 10′ deformity were randomised into two groups each using a different surgical approach to the knee joint but all patients receiving the same type of arthroplasty components. One group had the replacement arthroplasty utilising a standard medial para-patellar approach and incorporating a lateral retinacular release where required whilst the other group received a modified lateral capsular approach avoiding osteotomy of the tibial tubercle and repositioning vastus lateralis at closure. Both groups were well matched in terms of age and sex. Each patient was reviewed in a special clinic at one year post-op to establish functional outcome and to review post-operative complications and length of stay and to conduct a radiological assessment of the implant. Pre and post-operative assessment utilised the HSS and Oxford knee scores. The assessor (a research physiotherapist) was blinded to the randomisation.
Results: All one hundred patients will have had their twelve month follow-up by February 2002. The results of the first 67 knees have been analysed in a preliminary study. The knee post-operative HSS and Oxford scores for the medial capsular group were 77.4 and 26 respectively and for the lateral capsular group 81.2 and 26.8. 79.4% of the patients in the medial group and 88% of patients in the lateral group showed good to excellent results on HSS scoring. Average patient satisfaction on a scale of 10 was 7.9 for the medial group and 8.5 for the lateral group. Other criteria such as range of motion, correction of deformity and stability were comparable in the two groups but it was noted that there was a tendency to use more constrained implants in the medial group. The differences between the two sets of results are not statistically significant in this preliminary report. There was no increase in wound complications in the lateral group despite incomplete closure of the capsule.
Conclusion: The lateral capsular approach for replacement arthroplasty of the valgus arthritic knee is as safe and effective as the medial capsular approach. The lateral capsular approach appears to have some advantages in certain situations such as severe and unstable deformity associated patello-femoral maltracking and also appears to enable the use of less constrained implants.
The abstracts were prepared by Mr Roger Smith. Correspondence should be addressed to him c/o British Orthopaedic Association, Royal College of Surgeons, 35-42 Lindoln’s Inn Fields, London WC2A 3PN.
