Background Total hip arthroplasty (THA) is an effective procedure for patients with end-stage hip osteoarthritis. However, whether or not pre-operatively existing functional deficits are persisting several years post-surgery in the affected limb has not been thoroughly researched. Therefore, the primary aim of this preliminary study was to include patients four to five years after undergoing THA and to investigate potential differences between the operated and non-operated leg in hip strength, range of motion (ROM), balance, and gait. The secondary aim was to compare these values from the operated leg of the patients to those of the legs of healthy subjects. Methods Sixteen patients (age: 65.20 ± 5.32 years) following unilateral THA (post-operation time: 4.7 ± 0.7 years) and ten, healthy, age-matched control subjects (age: 60.85 ± 7.57 years) were examined for maximum isometric hip muscle strength, active ROM of the hip joint, balance and gait on both limbs. Paired t-tests were used to assess the inter-limb differences in the THA group. Analyses of covariance (ANCOVA) were performed to compare groups, using age as a covariate. Results The analysis of inter-limb differences in patients following THA revealed significant deficits on the operated side for hip abduction strength (p = 0.02), for hip flexion ROM (p < 0.01) and for balance in terms of the length of center of pressure (COP) (p = 0.04). Compared to values of the control subjects, the patients demonstrated significantly reduced hip strength in flexion, extension and abduction (p < 0.05) on the operated leg as well as reduced ROM measures in hip flexion, extension and abduction (p < 0.05). Conclusions The first results of this explorative study indicated that inter-limb differences as well as reduced hip strength and hip ROM compared with control subjects were still present four to five years after THA. These persisting asymmetries and deficits in patients following THA may be one explanation for the decrease in health-related quality of life (HRQoL) seen in patients over the years after surgery. Further studies are required to replicate these findings with a larger sample size. Trial registration DRKS, DRKS00016945. Registered 12 March 2019 – Retrospectively registered,

Backgroundː Total hip arthroplasty (THA) is a successful procedure to reduce pain and restore function in patients with end-stage hip osteoarthritis. However, whether or not pre-operatively existing deficits in strength, balance, range of motion (ROM) and gait are persisting several years post-surgery in the affected limb has not been thoroughly researched. Therefore, the aim of the study was to investigate inter-limb differences in patients who had undergone THA four to five years ago and to compare the values of the operated leg to controls. Methodsː Sixteen patients (age: 65.20±5.32 years) following unilateral THA (post-operation time: 4.7±0.7 years) and ten, healthy, age-matched controls (age: 60.85±7.57 years) were examined for maximum isometric hip muscle strength, active ROM of the hip joint, balance and gait on both limbs. Paired t-tests were used to assess the inter-limb differences in the THA group. Analyses of covariance (ANCOVA) were performed to compare values of the operated leg to controls, using age as a covariate. Results: The analysis of inter-limb differences in patients following THA revealed significant deficits on the operated side for hip abduction strength (p=0.02), for hip flexion ROM (p<0.01) and for balance in terms of the length of center of pressure (COP) (p=0.04). Compared to values of the controls, the patients demonstrated significantly reduced hip strength in flexion, extension and abduction (p<0.05) on the operated leg as well as reduced ROM measures in hip flexion, extension and abduction (p<0.05). Conclusions: Inter-limb differences as well as reduced hip strength and hip ROM were still present four to five years after THA. These persisting asymmetries and deficits in patients following THA may be one explanation for the decrease in health-related quality of life (HRQoL) seen in patients over the years after surgery. Postoperative training focusing on strengthening hip muscles should be continued months and years after hip replacement in order to compensate persisting deficits and asymmetries. Trial registration: DRKS, DRKS00016945. Registered 12 March 2019 – Retrospectively registered, http://www.drks.de/DRKS00016945

BackgroundːTotal hip arthroplasty (THA) is a successful method to reduce pain in end-stage hip osteoarthritis (OA) patients. If the pre-operatively existing deficits in the affected limb are persisting years after THA has not been thoroughly researched. Therefore, the aim of the study was to investigate potential side-to-side differences in long-time THA patients.MethodsːSixteen patients (age: 65.20 ± 5.32 years), who had undergone unilateral THA four to five years ago and ten, healthy, age-matched controls (age = 60.85 ± 7.57 years) were examined for maximum isometric hip muscle strength, range of motion (ROM) of the hip joint, balance and gait on both limbs. Paired t-testes were used to assess the inter-limb differences in THA patients and controls and unpaired t-tests were applied to investigate differences between the two groups.ResultsːIn THA patients, significant deficits on the operated side were found for the center of pressure (COP) length, hip abduction torque and ROM of hip extension with small to medium effects. Compared to the controls, THA patients demonstrated highly significantly reduced hip strength in flexion, extension, abduction and adduction as well as limited ROM in hip flexion and abduction.ConclusionsːA few side-to-side difference were present in THA patients four to five years after the surgery, although the general hip muscle weakness and restricted hip ROM compared to the controls was more severe. Postoperative training focusing on strengthening hip muscles should be continued months and years after the surgery in order to compensate persisting deficits.Trial registrationːDRKS, DRKS00016945. Registered 12 March 2019 – Retrospectively registered, http://www.drks.de/DRKS00016945

Backgroundː Total hip arthroplasty (THA) is an effective procedure for patients with end-stage hip osteoarthritis. However, whether or not pre-operatively existing functional deficits are persisting several years post-surgery in the affected limb has not been thoroughly researched. Therefore, the primary aim of the study was to investigate differences between the operated and non-operated leg in hip strength, range of motion (ROM), balance, and gait in patients four to five years after undergoing THA. The secondary aim was to compare these values from the operated leg of the patients to those of the legs of healthy subjects. Methodsː Sixteen patients (age: 65.20±5.32 years) following unilateral THA (post-operation time: 4.7±0.7 years) and ten, healthy, age-matched control subjects (age: 60.85±7.57 years) were examined for maximum isometric hip muscle strength, active ROM of the hip joint, balance and gait on both limbs. Paired t-tests were used to assess the inter-limb differences in the THA group. Analyses of covariance (ANCOVA) were performed to compare groups, using age as a covariate. Results: The analysis of inter-limb differences in patients following THA revealed significant deficits on the operated side for hip abduction strength (p=0.02), for hip flexion ROM (p<0.01) and for balance in terms of the length of center of pressure (COP) (p=0.04). Compared to values of the control subjects, the patients demonstrated significantly reduced hip strength in flexion, extension and abduction (p<0.05) on the operated leg as well as reduced ROM measures in hip flexion, extension and abduction (p<0.05). Conclusions: Inter-limb differences as well as reduced hip strength and hip ROM compared with control subjects were still present four to five years after THA. These persisting asymmetries and deficits in patients following THA may be one explanation for the decrease in health-related quality of life (HRQoL) seen in patients over the years after surgery. Postoperative training focusing on strengthening hip muscles should be continued months and years after hip replacement in order to compensate persisting deficits and asymmetries. Trial registration: DRKS, DRKS00016945. Registered 12 March 2019 – Retrospectively registered, http://www.drks.de/DRKS00016945