The effect of hip abductor muscle strengthening training on knee muscle strength and functional performance after medial patellofemoral ligament reconstruction

The aim of this study was to investigate the effects of standard rehabilitation program after medial patellofemoral ligament (MPFL) reconstruction and hip abductor muscle strengthening exercise training applied in addition to the standard rehabilitation program on knee muscle strength development and functional performance. Thirty patients (mean age: 22.18±4.4 years; mean BMI: 25.92±4.29 kg/m2), aged 18-45 years, who had undergone MPFL reconstruction were included in the study. The patients were randomly divided into two groups. Rehabilitation program consisting of cold application, manual therapy and exercises was applied to both groups for 12 weeks postoperatively. Standard rehabilitation program exercises were given to the group called SRG (n=15; mean age: 20.75 (3.69) years; BMI: 28.32 (5.96) kg/m2), and to the group called KAEG (n= 15; mean age: 23 (4.78) years; BMI: 24.55 (2.27) kg/m2), hip abductor muscle strengthening exercises were given in addition to this program. Before and after the training, Kujala, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Tegner and Lysholm scores and knee function levels of the patients were evaluated. Quadriceps, hamstring, hip abductor and adductor muscle strength, functional performance (single leg forward jump test, triple jump test), dynamic balance (y balance test) of all patients were evaluated at 6 months postoperatively. In statistical analysis, t-test for independent groups was used for intergroup comparisons of repeated measures ANOVA analysis evaluation parameters for the variation of patients' knee function scores over time. Quadriceps hamstring and hip abductor / adductor isokinetic muscle strength measurements were higher in the hip abductor exercise group in all parameters for the operated extremity (p<0.05). Single leg forward jump distance and leg symmetry index were better in the hip abductor exercise group in three-step jump distance and leg symmetry values, respectively. (p=0.02, p=0.05, p=0.02, p=0.05). The hip abductor exercise group obtained higher values when the results of functional tests and subjective scales (Y balance Test, Kujala, IKDC Subjective Knee Evaluation Form, Tegner and Lysholm) were examined (p<0.05). As a result of our study, it was found that hip abductor muscle strengthening trainings were more effective in increasing knee muscle strength and functional performance in patients after MPFL reconstruction. We think that hip abductor muscle strengthening training is an alternative method that can be used in rehabilitation after MPFL reconstruction. Keywords: patellar dislocation, exercise, rehabilitation, exercise therapy