The continuous growth in the proportion of the population with obesity, combined with an increased demand for knee arthroplasty as the population becomes increasingly elderly, will inevitably lead to a rise in the number of obese patients requesting knee replacement surgery. Knee arthroplasty surgery has progressed substantially in recent years but many technical challenges are still inherent in this surgical procedure in obese or morbidly obese patients. There are several studies demonstrating that obese patients enjoy less functional or subjective improvement than their non-obese counterparts after a knee replacement operation. There is a significant risk for perioperative and postoperative infections or other complications. This entirety will pose a major challenge for orthopaedic surgeons in the coming years. Therefore, we will need more high quality prospective research in the future.
7 Conclusion
The main conclusions emerging from this research are as follows:
1. The early postoperative functional level of obese patients was inferior to non-obese patients. Obesity was also associated with an increased risk for perioperative technical errors and postoperative detrimental consequences.
2. Obese patients had poorer clinical success and self-assessed outcome after TKA in the long term (over one decade) follow-up. Womac scores were significantly higher in obese patients and KSS values and the range of motion were poorer. It is concluded that obesity exerts a negative effect on the long term outcome of TKA.
3. UKA revision patients were more dissatisfied according to the self-assessed WOMAC scale during follow-up. There was less improvement of the range of motion in UKA revision cases, although ROM at the follow-up was similar. However there were no statistically significant differences between the groups with regard to complications and radiological results. To conclude, it seems that UKA conversion to TKA is associated with poorer clinical outcome as compared to those achieved with primary TKA.
4. The periprosthetic femoral BMD decreases up to 7 years after TKA. This bone loss is likely to be caused by the stress-shielding phenomenon and immobilization in the first postoperative phase. However, in later years, age-related bone loss may also play a role.
This study also showed that obese patients had higher periprosthetic BMD than non-obese patients both at baseline and throughout the follow-up. This may be due to higher weight-related stresses on bone. Nonetheless, in this study, the loss of bone density was not associated with negative clinical outcomes.
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