Abstract
[Introduction]
Rapid increase of aged population has been one of major issue affecting national health care plan in Japan. In 2006, Japanese Orthopaedic Association indicated a new clinical entity of musculoskeletal ambulation disorder symptom complex (MADS) to define the higher risk of fall and ambulatory disability in the elderly population caused by musculoskeletal disorders. Osteoarthritis of the knee is one of major cause of MADS. The number of patients with MADS underwent total knee arthroplasty (TKA) had been increased in Japan, and also expected to increase worldwide in the near future. The effectiveness of TKA for the patient with MADS would be a key issue for the patient satisfaction in TKA. In the present study, we analyzed the influence of pre-operative factors on the ambulatory functions in the patients of primary TKA.
[Material & Method]
132 patients with osteoarthritic knees implanted with posterior-stabilized (PS) TKAs were subjected to this study. There were 113 female and 19 male patients. The mean age of the patients was 73.6 years (range, 59 to 87 years). Patients were pre-operatively subjected to 2 functional performance tests which were essential tests for MADS diagnosis. Firstly, 3 meter timed up and go test (TUG) was used to evaluate ambulation ability. Secondary one leg standing time (ST) with open eyes was measured with both operated and non-operated leg to assess balancing ability. MADS was diagnosed if TUG and ST were not less than 11 seconds and/or less than 15 seconds respectively. The influence of each pre-operative factor was evaluated simple linear regression analysis (p < 0.05). Pre-operative factors consisted of age, sex, weight, height, BMI, standing femoro-tibial angle (FTA) and active knee range of motion.
[Results]
Pre-operatively, 74% of the patients was diagnosed as MADS, with the results of 64, 74 and 64% of the patient matched to the MADS criteria with the evaluation of TUG and ST with operated and non-operated leg respectively (Fig 1). Firstly, pre-operative TUG was found to be negatively correlated to the weight (R = −0.25), ST with non-operated leg (R = −0.24) and active knee flexion angle (R = −0.28, Fig 2). Secondary, ST with operated leg was significantly affected by age (R = −0.32), standing FTA (R = −0.38) and ST with non-operated leg (R = 0.66, Fig 3).
[Discussion & Conclusion]
As much as 74% of our patients was suffered from MADS before primary TKA. Majority of patient had both ambulatory and balancing disability with higher risk of fall and ambulatory dysfunction. We found ST with non-operated leg significantly affected both TUG representing ambulatory function and ST representing balancing function. This means the contra-lateral lower extremity function would play an important role on the pre-operative functional ability in the patient of TKA. Furthermore, we found pre-operatively that active knee flexion influenced ambulatory function, and coronal knee deformity deteriorated balancing ability.
Then we should evaluate these pre-operative factors in analyzing the effectiveness of TKA on the functional recovery in the elderly patient underwent primary TKA.
