New and updated reviews published by the Cochrane collaboration

Rehabilitation following TKR

Total knee replacement is a complex intervention. The individual components required to provide care number in the hundreds and in each centre there are multiple differences in everything from the post-operative physiotherapy regime to the type of raised toilet seat provided – each of which could reasonably affect the outcome of the patients. Determining what causes successful outcomes following total knee arthroplasty (TKA) can be very tricky and, while clearly multifactorial, adequate post-operative rehabilitation is likely to have an important part to play. There are many potential regimes which can be patient- or therapist-led, group or individual. One area that evokes particular debate is the application of Continuous Passive Motion (CPM) which has also been used in many centres as part of a standard post-operative regimen. It is postulated that CPM prevents knee stiffness and improves range of motion, among other therapeutic benefits, however, controversy over its use still remains, with surgeons not using it at all or only using it in specific clinical situations. In a much larger than average review from Australia, researchers analysed 24 RCTs that compared CPM and standard care with standard post-operative care without CPM. The participants in the analysed studies totaled 1445, with all included in qualitative and meta-analyses.⁴ Meta-analyses of pooled data looking at short-term active knee flexion found a benefit of only 2° with CPM. Furthermore, medium- to long-term effects on all active and passive ROM found mean effects of CPM to be less than 3° across the board. These results were not statistically significant and the authors suggest that most patients, let alone clinicians, would struggle to even notice an improvement of 2° to 3° , never mind deem it to be clinically important enough to justify the widespread use of CPM. Eight trials totaling 581 participants reported on risk of manipulation under anaesthesia (MUA) following TKA. Only 25 (7%) of these participants required an MUA following surgery. Analyses found low-quality evidence that CPM reduces the risk of MUA with reported relative risk of 0.34. An RR of 0.34 with an incidence proportion of 7% corresponds to an absolute overall risk reduction of MUA of 4%. However, the authors also clearly state that the RR is imprecise with large confidence intervals making a smaller effect a possibility. None of these eight studies performed well on evaluation of study quality and most had methodological flaws and so, together, the evidence for CPM and risk of MUA is unreliable. Post-operative knee pain was also subject to evaluation with eight studies totaling 414 participants reporting on pain outcomes. For the most part, the evidence was of low quality suggestive of no statistically or clinically significant differences in short-, medium- or long-term pain scores. The results of the quantitative analysis for length of stay were difficult to draw conclusions from but showed a mean difference of 0.4 days in favour of the group receiving CPM. However, again with a wide confidence interval the true effect could be clinically meaningful. The authors suggest that the quality of the evidence is variable across the board and intervention effects are either too small or unclear to justify the use of CPM routinely in standard post-operative care for TKA – a conclusion that none of us here at 360 find to be too controversial.