Is it possible to replicate the study using the description in the methods section?
Is the patient cohort adequately reported on, e.g. age, sex distribution, concomitant injuries, surgical procedure?
Was a sample size calculation performed? This is especially important if groups were compared and no difference was found? Is it because there is no difference or because the sample size is to low.
Is the randomization of the study adequately described?
Are the numbers quality tested, e.g. reliability measurements such as test-retest? If it is deficient it can be addressed in the revised version.
For clinical and animal studies, do the authors provide an IRB/ethical committee approval?
If it is a prospective clinical study, the study should be registered in a clinical study register. This can be local register, which submits its data to https://clinicaltrials.gov or directly at clinicaltrails.gov.