The evaluation of two methods for the placement of the tibial component of total knee arthroplasties in obese patients

Between December 2004 and October 2008 we studied 38 obese patients who underwent cemented total knee arthroplasty (using the rotating platform tibial tray) due to medial compartment osteoarthritis and consequent varus deformity. All patients had a body mass index (BMI)> 40. Functional outcome was assessed using the Knee Society Score (KSS). The study was based on the comparison between extramedullary (group A) and intramedullary (group B) instrumentation systems for the placement of the tibial prosthesis. The main endpoint was the immediate post-operative knee joint alignment.

There were 10 male and 28 female patients. The average follow-up period was 13.8 months (minimum follow-up of 6 months). There were 22 patients in group A whereas 16 patients comprised group B. In 5 of the 22 patients in group A there was an average varus malalignment of 40 and a mean KSS of 71.5 at the time of the latest follow-up visit. In the rest of patients of both groups there was a valgus alignment between 0 and 70 and a mean KSS of 86.4 respectively

Our experience suggests that the intramedullary instrumentation technique for the placement of the tibial component offers a more favourable post-operative alignment as well as better functional outcome in obese patients.

The timing of performing knee arthroplasties in bilateral osteoarthritic knees remains controversial. Our aim was to compare one-stage with two-stage bilateral knee arthroplasties (TKA).

Between November 2004 and April 2008, 128 patients (72 female and 56 male) underwent one-stage bilateral TKAs. Another group of 115 patients that underwent two-stage procedures during the same period formed the control group. All patients received the same type of anaesthesia. Study parameters included age, weight, medical co-morbidities, length of hospital stay, blood loss, post-operative complications and functional outcome.

There were no significant differences between the two groups. Co-morbidities and functional outcome based on the Knee Society Score were similar in both groups. In the one-stage group the length of hospital stay and blood losses were higher than the two-stage group; however less than double compared to the two-stage group. The early post-operative complications were higher but not statistically significant in the one-stage group.

Despite the fact that the early post-operative complications are slightly higher in the one-stage group, this particular method is an effective way of dealing with bilaterally osteoarthritic knees. It offers excellent functional outcome at a reduced cost