Studies of surgical outcome after patellar tendinopathy: clinical significance of methodological deficiencies and guidelines for future studies

Patellar tendinopathy is often treated surgically after failure of conservative treatment but clinical experience suggests that results are not uniformly excellent. The aim of this review was to (i) identify the different surgical techniques that have been reported and compare their success rates, and (ii) critically assess the methodology of studies that have reported surgical outcomes. Twenty-three papers and two abstracts were included in the review. Surgical procedures were categorized and outcomes summarized. Using ten criteria, an overall methodology score was derived for each paper. Criteria for which scores were generally low (indicating methodological deficiency) concerned the type of study, subject selection process and outcome measures. We found a negative correlation between papers' reported success rates and overall methodology scores (r= -0.57, P<0.01). There was a positive correlation between year of publication and overall methodology score (r=0.68, P<0.001). We conclude that study methodology may influence reported surgical outcome. We suggest practical guidelines for improving study design in this area of clinical research, as improved study design would provide clinicians with a more rigorous evidence-base for treating patients who have recalcitrant patellar tendinopathy.