Is Isokinetic Testing an Indicator of Total Knee Arthroplasty

In this study, investigators analyzed whether the isokinetic knee muscle strength of patients undergoing unilateral total knee arthroplasty (TKA) is a predictor for surgery. Patients and Methods: In total, 29 unilateral TKA candidates (58 knees; mean age = 66.69 ± 7.42 years; mean symptom duration = 10 ± 5.40 years) were enrolled. The knees of patients with bilateral advanced knee osteoarthritis (stage 3 or 4), according to the Kellgren-Lawrence (K-L scale), that were scheduled for unilateral TKA were divided into surgical and non-surgical groups. An isokinetic testing system was used to assess knee flexor and extensor muscle strength (peak torque) at angular velocities of 60°/s and 180°/s (five cycles per velocity). The radiological (X-ray-based K-L scale and magnetic resonance imaging (MRI)-based quadriceps angle) and clinical findings (isokinetic test and visual analog scale pain scores) in both groups were compared. The isokinetic test results correlated with the radiological findings of the surgery group.

After the surgical decision was made, the patients were referred to the physiatrist by the orthopedist without informing which knee would be operated on. The physiatrist and the patient did not know which knee would be operated, so the tests were performed blindly.

This study analyzed 58 knees of 29 unilateral TKA candidates, divided into the surgical and non-surgical knee groups

This study analyzed 58 knees of 29 unilateral TKA candidates, divided into the surgical and non-surgical knee groups

The strength (PT) of the bilateral knee flexors and extensors were tested with isokinetic test. Tests were performed under the guidance of a rehabilitation medicine specialist, and the system was calibrated prior to their commencement. The patients were seated in upright position and were fixed with pelvic and thigh belts. Concentric extension (PT_E) and concentric flexion (PT_F) were measured between the 0° and 90° knee ranges at angular velocities of 60°/s and 180°/s (60 PT_E, 60 PT_F, 180 PT_E, and 180 PT_F, respectively) The tests were repeated five times at each velocity, and the highest PTs were selected for statistical analysis. The participants performed repeated trials before sets, while a 20-second rest was provided between sets.

In the isokinetic evaluation, both 60 PT_E (Peak Torque _Extension) and 60 PT_F (Peak Torque_Flexion) were evaluated.The tests were repeated five times at each velocity, and the highest PTs were selected for statistical analysis. The participants performed repeated trials before sets, while a 20-second rest was provided between sets.

Kellgren-Lawrence grading system was used. Each radiograph was assigned a grade from 0 to 4, which correlated to increasing severity of OA, with Grade 0 signifying no presence of OA and Grade 4 signifying severe OA

The visual analog scale (VAS) pain score of each individual was also recordedThe Visual Analogue Scale (VAS) measures pain intensity. The VAS consists of a 10cm line, with two end points representing 0 ('no pain') and 10 ('pain as bad as it could possibly be'). Investigators asked the patient to rate their current level of pain by placing a mark on the line.

Q angle of knees were recorded. It is defined as the angle formed between the quadriceps muscles and the patella tendon.The Q angle measured in standing. Normal Q angle score for females is between 13-18° and in males is between 12-15°, with values greater than and lesser these are considered abnormal

Inclusion Criteria: Diagnosis of advanced (Kellgren-Lawrence stage 3 or 4) bilateral knee osteoarthritis (OA). Unilateral total knee replacement surgery recommended by orthopedics according to pain status Exclusion Criteria: Neurological diseases that could affect knee muscle strength Rheumatological diseases Diagnosis of osteoarthritis below 3 according to Kellgren-Lawrence classification