Strength and Functional Deficits Following Total Hip Replacement in Individuals with Avascular Necrosis of Femoral Head

Abstract

Background: AVN commonly affects femoral head causing pain, joint stiffness, muscle wasting and physical disability. THR, commonly done for AVN improves mobility, strength and physical functions by reducing pain and improving functions. Methodology: Total 32 subjects, 16 age & gender matched healthy adults and 16 with AVN of femoral head were included. Muscle strength of hip muscles by modified sphygmomanometer, self reported Harris hip score and TUG test were taken preoperatively in subjects with AVN scheduled for a THR. All subjects underwent physiotherapy during hospital stay. Again all outcome measures were taken post hip replacement on the day of discharge. In healthy adults, only hip muscle strength was measured. Results: 32 subjects, 28-males and 8-females. Mean age-36.88 years in both groups. Isometric muscle strength preoperatively in AVN subjects of hip flexors-76.75±50.67 mm of Hg, abductors-54.56±30.74 and extensor apparatus 75.38±37.32 was significantly reduced (p<0.001) compared to healthy adults,(hip flexors-188.42±15.69, abductors 112.67±21.66 and extensor apparatus-171.71±25.60). Postoperatively strength of hip flexors-93.12±52.58, abductors-63.62±33.74 and extensor apparatus-88.94±41.22 was reduced compared to healthy adults. Postop significant improvement (p<0.05) seen at discharge in strength compared to preop values. Conclusion: Muscle strength of hip muscles in subjects with AVN preoperatively and post replacement was significantly reduced compared to normals. Postoperatively improvement was seen at discharge in strength compared to preoperative values.