Introduction

Many determinants of the length of stay (LOS) for primary total knee arthroplasty (TKA) have been described. Multimodal, pre-emptive analgesia, age, walking aid score and stair score are some of them. Single shot peripheral nerve block is a popular method to provide prolonged analgesia in immediate post operative period after TKA. Delayed recovery from the nerve block can delay the rehabilitation programme and subsequently lengthen the LOS when the multi disciplinary team discharge criteria are well defined and standardized.

The aim of this study is to calculate the incidence of delayed recovery from the sciatic and femoral nerve block administered in cases of primary TKA and its influence on LOS.

Surgeon’s ability to anticipate the implant size requirements for total knee replacements is important to the success of the procedure. Previously, this has been inconsistently accomplished using plain radiographs. The purpose of this study is to assess the accuracy of digital templating software in predicting the size requirements of the femoral and tibial implants in total knee replacements.

Thirty consecutive PFC (DePuy) total knee replacements were templated preoperatively using digital templating software (TraumaCad, Orthocrat Ltd). The knees were templated by two surgeons working independently using standardised digital AP and lateral radiographs. All films were magnification-calibrated using markers of known size. Postoperatively, the predicted implant size was compared to the actual components selected at the time of surgery.

The size of the femoral prosthesis was accurately selected on the AP view in 53.5% and on the lateral in 66% of cases. The size of the tibial implant was correctly selected on the AP view in 65.5% and on the lateral in 70.5% of cases. The tibial prosthesis was always templated within one size. The femoral prosthesis was predicted within two sizes (93% on AP + 98% on lateral +/− 1 size). There was no correlation with failure of the software to recognise the metal marker and inadequate lateral x-rays.

The lateral x-ray was found to be more reliable than the AP on predicting both the femoral and tibial implants. The tibia was more accurately templated than the femur on average. There was good inter-observer and intra-observer reliability for both prostheses (0.75 – 0.85). Discrepancies in templating may have been due to inaccuracies in placement of the metal marker at the time of x-raying or due to fixed flexion deformities, which may have affected the magnification of the x-ray. Overall, templating using digital software was marginally superior to the standard acetate method.

Objective: to determine if the outcome of TKR was affected by the level of pre-operative symptom severity.

Methods Between June 1998 and Nov 2001, 207 primary TKRs (AGC) were performed in 178 patients for OA of the knee. Data on patient demographics, Oxford knee score (OKS), AKSS and ABC health category were collected prospectively pre-operatively and at the 2 year review. For analysis, patients were arbitrarily categorised into four quartile groups with pre-operative OKS of 0–12, 13–24, 25–36 and 37–48.

Results The entire group had a pre-op mean OKS of 18.4. The 2 year post-op mean outcome measures were OKS 38.2 (79.6%), AKSS 87.8, Function 76.3.

Conclusion Rather than all patients achieving a uniform outcome post-TKR, patients with more severe symptoms, as indicated by lower pre-operative Oxford Knee Scores, tend to have the most to gain but achieve poorer absolute outcomes (from both patient’s (OKS) and surgeons’ perspectives (AKSS)). Conversely, at the other end of the spectrum, even patients with relatively high pre-operative OKS, (better than the units post-op mean) achieved better post-op scores . The results suggest that waiting too long before intervention compromises the final outcome.