In patients eligible for meniscal surgery who first receive physical therapy, multivariable prognostic models cannot predict who will eventually undergo surgery

Abstract

Purpose Although physical therapy is the recommended treatment in patients over 45 years old with a degenerative meniscal tear, 24% still opt for meniscal surgery. The aim was to identify those patients with a degenerative meniscal tear who will undergo surgery following physical therapy. Methods The data for this study were generated in the physical therapy arm of the ESCAPE trial, a randomized clinical trial investigating the effectiveness of surgery versus physical therapy in patients of 45–70 years old, with a degenerative meniscal tear. At 6 and 24 months patients were divided into two groups: those who did not undergo surgery, and those who did undergo surgery. Two multivariable prognostic models were developed using candidate predictors that were selected from the list of the patients’ baseline variables. A multivariable logistic regression analysis was performed with backward Wald selection and a cut-off of p < 0.157. For both models the performance was assessed and corrected for the models’ optimism through an internal validation using bootstrapping technique with 500 repetitions. Results At 6 months, 32/153 patients (20.9%) underwent meniscal surgery following physical therapy. Based on the multivariable regression analysis, patients were more likely to opt for meniscal surgery within 6 months when they had worse knee function, lower education level and a better general physical health status at baseline. At 24 months, 43/153 patients (28.1%) underwent meniscal surgery following physical therapy. Patients were more likely to opt for meniscal surgery within 24 months when they had worse knee function and a lower level of education at baseline at baseline. Both models had a low explained variance (16 and 11%, respectively) and an insufficient predictive accuracy. Conclusion Not all patients with degenerative meniscal tears experience beneficial results following physical therapy. The non-responders to physical therapy could not accurately be predicted by our prognostic models. Level of evidence III.

Effect of Physical Therapy vs Arthroscopic Partial Meniscectomy in People With Degenerative Meniscal Tears

“…Previous studies investigated specific patient characteristics and combinations of characteristics to estimate treatment outcome and possible subgroups of patient who will benefit more from surgery compared with physical therapy. [31][32][33][34] However, none of these studies were able to find such a subgroup of patients. This finding is in line with ours, showing that physical therapy is noninferior to arthroscopic partial meniscectomy in patients with degenerative meniscal tears.…”

Predictors of the outcome of physiotherapy following a meniscus tear: A systematic review

“…Of the seven primary research studies [11] [18][19] [20][21] [22][30], four were randomised controlled trials (RCTs) [11] [18][19] [30] and three were cohort studies [20][21] [22]. The secondary exploratory analysis of outcome predictors were from the four separate RCT's [23][24][25] [26][27] [28][29] [31]. The three cohort studies followed subjects with a meniscus tear undertaking a course of physiotherapy [19] and subsequent APM if required [20] [21] Of the seven primary research studies, two RCTs [11][19] and one cohort study [22] only included subjects with a non-traumatic degenerative meniscus tear.…”

“…Five studies (621 participants) have examined the association of baseline pain levels with the outcome of physiotherapy treatment [20][24] [29][30] [31]. One RCT [30], two RCT secondary analysis [24] and one cohort study [20] report an association between baseline pain and the outcome of physiotherapy.…”

“…One RCT [30], two RCT secondary analysis [24] and one cohort study [20] report an association between baseline pain and the outcome of physiotherapy. One secondary analysis reports an association on univariate regression analysis but has not been included on the multivariate analysis [31] and one secondary exploratory analysis shows no association [29]. In the ESCAPE RCT [30] post hoc analysis of outcomes showed that for every millimetre increase in reported baseline pain during weight bearing (VAS 0-100) the effect of APM provided 0.14 greater IKDC score than physiotherapy (regression coefficient 0.14 [95%CI 0.01 to 0.27, p=0.03).…”

An individualized decision between physical therapy or surgery for patients with degenerative meniscal tears cannot be based on continuous treatment selection markers: a marker-by-treatment analysis of the ESCAPE study

“…Previous studies tried to define these subgroups [ 19 , 25 ]. However, neither multivariable prognostic models [ 16 , 19 ] nor surgeons’ personal predictions were able to accurately predict treatment outcome [ 25 ].…”