The current study aimed to compare simultaneous bilateral versus unilateral TKR on pain intensity and recovery of function at 30-days postoperatively. Results of the current study indicated that both groups showed a significant pain relief and improved function after TKR at 30 days post-operatively. There was no significant difference noted between simultaneous bilateral versus unilateral TKR on pain intensity and recovery of function.
Some studies indicate that simultaneous bilateral TKR surgery reduces rehabilitation time and have no additional risk for postoperative complications compared to unilateral TKR [29-32][32-35]. Additionally, the patient satisfaction scores, and functional outcomes are comparable, or better, in patients undergoing bilateral TKR than unilateral TKR, and this achieves without any additional medical costs [18,29][18,32]. While other studies reported statistically insignificant differences in pain reduction and functional recovery between bilateral versus unilateral TKR [29,33][32, 36], many studies indicated an increased postoperative complications and higher rehabilitation costs, in patients undergoing bilateral TKR than unilateral TKR [9,34,35][9,37,38].
Recently, a study reported that bilateral simultaneous unicompartmental knee arthroplasty shows better functional recovery at 6 month post-operatively than unilateral TKR . However, a direct comparison could not be made as many methodological differences existed between previous and current study. First, previous study compared bilateral simultaneous unicompartmental knee arthroplasty with unilateral TKR; in contrast, the current study compared bilateral simultaneous TKR with unilateral TKR. Second, previous study compared outcome at 6 months postoperatively, in contrast, the current study compared outcome at one month postoperatively.
TKR is most common and successful surgical intervention to reduce pain and improve function in patients with end stage osteoarthritis [37,38][29,30]. There are many factors should be considered before deciding surgical intervention such as patient’s age, severity, symptom duration, pre-operative medical condition, and unilateral or bilateral involvement . The commonest indications for TKR include OA, traumatic arthritis and rheumatoid arthritis . In the current study, all patients had a diagnosis of primary knee OA.
It has been recommended that patients undergo simultaneous bilateral TKR surgery had a prolong rehabilitation, increased length of hospital stay, higher blood transfusion, increased number of painful postoperative days, a greater number of complications, and increased financial burden . Nonetheless, these parameters have been showed significantly better than in those patients undergo staged arthroplasty surgery [18,40,41]. Although several studies indicated that postoperative medical complications often seen in patients undergo simultaneous bilateral TKR surgery [42-44], other studies indicated similar complication rates [45,46].
It is well established that TKR reduces knee pain and improves physical function in patients with knee OA. In line with previous studies, the current study reported reduced pain intensity and improved physical function in both simultaneous bilateral or unilateral TKR groups. The changes in pain intensity and physical function were statistically and clinically significant and were greater than reported minimally clinical important difference [47-49]. The current study reported a higher reduction in pain intensity in both groups than previous study (75% versus 47%) . In contrast to previous study, simultaneous bilateral TKR group reported little higher functional improvement than unilateral TKR group (71% versus 66%) in the current study . However, there were some methodological differences exists between current and former study. Number of simultaneous bilateral TKR group was large (63% versus 27%) in the current study while in the previous study unilateral TKR group was large (69% versus 31%). Additionally, previous study used the Western Ontario McMaster universities osteoarthritis index while the current study used LEFS to assess physical function.
The current study has several potential limitations. In the current study, physical function was assessed using LEFS, which is a subjective self-report functional scale. An objective outcome measure could be included to assess wide range of physical function. For instance, various performance based outcome measures such as timed up and go test and stair climbing test could be used to better understand functional recovery in these population. Additionally, the current study only assessed pain and function. Other important outcome measures such as ambulation, muscle strength, mobility, range of motion, and quality of life are warranted to consider in future study. The result of this study was restricted to simultaneous bilateral or unilateral TKR in patient with end stage OA, and therefore it might limit the generalizability of findings to other types of replacement surgeries. Additionally, the current study compared simultaneous bilateral TKR with a single unilateral TKR instead a staged bilateral TKR. Therefore, randomized controlled studies are warranted to further identify the differences in the various outcomes between simultaneous and staged bilateral TKR. Moreover, future study may investigate the effect of physiotherapy intervention to reduce post-operative complications and improve functional outcomes after simultaneous bilateral or unilateral TKR.