Journal of Trauma & Treatment

Microfracture of the Knee: Which Findings Can Be Derived From Statistical Analyses Summarizing 16 Studies?

Abstract

Lukas Leopold Negrin and Vilmos Vécsei

Objective: To statistically summarize all available results presented in the literature; to compute an inherently meaningful best estimate of the mean expectable treatment effect; to provide statistical evidence that advanced age and large chondral lesions adversely effect the outcome after microfracture.
Methods: We searched four electronic databases for prospective and retrospective studies that included sufficient statistical information. In order to convert all score values to the most frequently used Lysholm Score a regression analysis had to be performed at first, using data of 26 own patients. Subsequently, meta-, subgroup and regression analyses were performed.
Results: 16 studies representing 777 patients aged from 13 to 72 years with chondral lesions from 0.2 cm² to 20 cm² of size, evaluated after a follow-up period of six to 17 years referred to our eligibility criteria. We calculated an overall best estimate of 26.76 Lysholm points for the mean treatment effect. With values of 22.38 Lysholm points for group 1 (patients younger than 38 years on average) and 31.11 Lysholm points for group 2 (patients with a mean age greater-than-or-equal to 38 years) our subgroup analysis revealed a barely significant difference between the two means (p=0.499). Due to the fact that the mean preoperative score value in group 2 was considerably lower than in group 1 these findings might be caused by the uneven increase of the Lysholm Score and not by age-related facts. However, neither a subgroup analysis referring to the defect size, nor a linear regression with mean age as the predicting variable could reveal significant results.
Conclusion: Our meta-analysis enables patients to take a realistic view on their improvement in quality of life after knee microfracture, but it does not facilitate surgeon’s decision whether microfracture is the appropriate technique to treat a given full-thickness cartilage lesion of the knee.