Letter regarding “Does cruciate-retaining total knee arthroplasty enhance knee flexion in Western and East Asian patient populations? A meta-analysis”

The study by Sumino et al. [1] aimed at evaluating the clinical effects of cruciate-retaining total knee arthroplasty in patients with knee osteoarthritis or rheumatoid arthritis. Conclusion based on this comprehensive search andmeta-analysis showed that cruciate-retaining total knee arthroplasty did not enhance post-operative flexion capability neither in the Western nor East Asian. We note the following problems, which hamper the review's validity.