R.W. Nutton

Knee joint kinematics in gait and other functional activities measured using flexible electrogoniometry: how much knee motion is sufficient for normal daily life?

The knee joint kinematics of a group (n=20) of elderly normal subjects (mean age=67 years) were investigated using flexible electrogoniometry. The flexion-extension angle of the knee was recorded during a range of functional activities performed as part of a circuit in and around the hospital. The functions analysed including gait, walking on slopes, stair negotiation, the use of standard and low chairs and a bath. The data were used to produce the pattern of joint angulation against the percentage of the cycle for each individual conducting each activity. Further the maximum and minimum knee joint angles and the excursion of the joint during the cycle were identified. The results indicate gait and slopes require less than 90 degrees of knee flexion, stairs and chairs 90-120 degrees of flexion and a bath approximately 135 degrees of flexion. The data suggests that 110 degrees of flexion would seem a suitable goal for the rehabilitation of motion in the knee. It is concluded that flexible electrogoniometry is a suitable and practical method for evaluating knee motion during a range of functional activities.

A prospective randomised double-blind study of functional outcome and range of flexion following total knee replacement with the NexGen standard and high flexion components

Modifications in the design of knee replacements have been proposed in order to maximise flexion. We performed a prospective double-blind randomised controlled trial to compare the functional outcome, including maximum knee flexion, in patients receiving either a standard or a high flexion version of the NexGen legacy posterior stabilised total knee replacement. A total of 56 patients, half of whom received each design, were assessed pre-operatively and at one year after operation using knee scores and analysis of range of movement using electrogoniometry. For both implant designs there was a significant improvement in the function component of the knee scores (p < 0.001) and the maximum range of flexion when walking on the level, ascending and descending a slope or stairs (all p < 0.001), squatting (p = 0.020) and stepping into a bath (p = 0.024). There was no significant difference in outcome, including the maximum knee flexion, between patients receiving the standard and high flexion designs of this implant.

Knee joint functional range of movement prior to and following total knee arthroplasty measured using flexible electrogoniometry

The functional ranges of movement of the knee were investigated in a group of patients with knee osteoarthritis (n = 42, mean age 70 years) before, 4 months and at 18-24 months after total knee arthroplasty and then compared with age matched normal subjects (n = 20, mean age 67 years). Flexible electrogoniometry was used to record the maximum flexion-extension angle, the minimum flexion-extension angle and flexion-extension excursions of both knees during eleven functional activities along with the active and passive knee joint range of motion measured using a manual goniometer. Over the eleven functional activities the patients pre-operatively exhibited 28% less knee joint excursion than normal age matched subjects. By 18-24 months following total knee arthroplasty only 2% of this deficit was recovered. Statistically this recovery was only significant in level walking, slope ascent and slope descent. A greater range of movement was measured in a non-weight bearing position than was used in weight bearing functional activity. It is concluded that total knee arthroplasty gives rise to little improvement in knee motion during functional activities and that functional range of movement of the knee remains limited when compared to normal knee function for a minimum of 18 months following operation.

TREATMENT OF CHRONIC ROTATOR-CUFF IMPINGEMENT BY ARTHROSCOPIC SUBACROMIAL DECOMPRESSION

We report a prospective study of 49 patients who had arthroscopic subacromial decompression for chronic rotator-cuff impingement. All patients were assessed preoperatively and at 3, 6 and 12 months using the modified UCLA shoulder score. The dominant arm was affected in 35 patients, but only 13 recognised overuse as a cause of their shoulder pain. Before operation, the UCLA shoulder score was poor or fair in all patients. After three months only 28% of patients had satisfactory relief of symptoms but at one year 85% of patients examined had a good or excellent result. Patients with calcific tendonitis recovered more quickly: 93% reported a good result at six months. We conclude that arthroscopic subacromial decompression is an effective form of treatment, but that patients should be warned that recovery from surgery may be prolonged.

Movement of the knee in osteoarthritis: THE USE OF ELECTROGONIOMETRY TO ASSESS FUNCTION

We used electrogoniometers to measure the range of movement (ROM) of the knee during various activities, comparing 50 patients with osteoarthritis of the knee (OA) with 20 healthy age- and sex-matched subjects. The minimum and maximum joint angles and the ranges of excursion of the patient and control groups were tested for significant differences, using an unrelated Students t-test with pooled variance. Knee flexion in patients with OA was significantly reduced during all activities (p < 0.05), but differences in knee extension were not significant except when patients negotiated stairs. We believe that this reduction in ROM is caused by inhibition due to pain when load-bearing. Static non-load-bearing measurements of the ROM poorly reflected the functional ROM, with a coefficient of determination (r2) of 0.59 in the patient group and 0.60 in the control group. Electrogoniometry of the ROM of the knee provides a reliable, accurate and objective measurement of knee function.

Movement of the knee in osteoarthritis

We used electrogoniometers to measure the range of movement (ROM) of the knee during various activities, comparing 50 patients with osteoarthritis of the knee (OA) with 20 healthy age- and sex-matched subjects. The minimum and maximum joint angles and the ranges of excursion of the patient and control groups were tested for significant differences, using an unrelated Students t-test with pooled variance. Knee flexion in patients with OA was significantly reduced during all activities (p < 0.05), but differences in knee extension were not significant except when patients negotiated stairs. We believe that this reduction in ROM is caused by inhibition due to pain when load-bearing. Static non-load-bearing measurements of the ROM poorly reflected the functional ROM, with a coefficient of determination (r2) of 0.59 in the patient group and 0.60 in the control group. Electrogoniometry of the ROM of the knee provides a reliable, accurate and objective measurement of knee function.

The effect of total knee arthroplasty on joint movement during functional activities and joint range of motion with particular regard to higher flexion users

Purpose. To evaluate active and functional knee excursion of patients before and after total knee arthroplasty (TKA) and to determine whether TKA restores quality of life related to functional activities of daily living. Methods. Electrogoniometry was used to measure the functional movement of the knee during 11 activities of daily living in 50 patients who underwent TKA. These data were compared with the patients active range of motion and quality-of-life scores. Results. A cut-off point existed between loss and gain in flexion at between 90 and 95 degrees of preoperative active flexion. Two thirds of patients had preoperative flexion of more than 90 degrees, 83% of them had reduced flexion postoperatively. The remaining one third had preoperative flexion of 90 degrees or less, 85% of them had improved flexion postoperatively. A similar pattern of loss and gain occurred for functional movement of the knee. Reduced functional range was associated with significantly reduced physical quality of life compared with age-matched healthy subjects. Conclusion. Although TKA offers excellent pain relief and contributes to the overall well-being of the patient, these results suggest that it also leads to a reduced range of active and functional motion in the majority of patients. This is associated with a lower-than-normal physical quality of life. The design of implants and rehabilitation programmes should be reconsidered so that better range of motion and quality of life can be achieved for patients.

Does a mobile-bearing, high-flexion design increase knee flexion after total knee replacement?

This prospective randomised controlled double-blind trial compared two types of PFC Sigma total knee replacement (TKR), differing in three design features aimed at improving flexion. The outcome of a standard fixed-bearing posterior cruciate ligament-preserving design (FB-S) was compared with that of a high-flexion rotating-platform posterior-stabilised design (RP-F) at one year after TKR. The study group of 77 patients with osteoarthritis of the knee comprised 37 men and 40 women, with a mean age of 69 years (44.9 to 84.9). The patients were randomly allocated either to the FB-S or the RP-F group and assessed pre-operatively and at one year post-operatively. The mean post-operative non-weight-bearing flexion was 107° (95% confidence interval (CI) 104° to 110°)) for the FB-S group and 113° (95% CI 109° to 117°) for the RP-F group, and this difference was statistically significant (p = 0.032). However, weight-bearing range of movement during both level walking and ascending a slope as measured during flexible electrogoniometry was a mean of 4° lower in the RP-F group than in the FB-S group, with 58° (95% CI 56° to 60°) versus 54° (95% CI 51° to 57°) for level walking (p = 0.019) and 56° (95% CI 54° to 58°) versus 52° (95% CI 48° to 56°) for ascending a slope (p = 0.044). Further, the mean post-operative pain score of the Western Ontario and McMaster Universities Osteoarthritis Index was significantly higher in the RP-F group (2.5 (95% CI 1.5 to 3.5) versus 4.2 (95% CI 2.9 to 5.5), p = 0.043). Although the RP-F group achieved higher non-weight-bearing knee flexion, patients in this group did not use this during activities of daily living and reported more pain one year after surgery.

Range of flexion after primary TKA: the effect of soft tissue release and implant design.

Range of motion following total knee arthroplasty (TKA) is a crucial measure of clinical outcome. The purpose of this randomized, controlled study was to determine which factors are predictive of postoperative range of flexion. Fifty-six patients received either a standard or a high-flexion design NexGen Legacy Posterior-Stabilized TKA (Zimmer, Warsaw, Indiana). The relationship between preoperative flexion, intraoperative flexion, and range of flexion 1 year postoperatively was determined. The influence of soft tissue release and the type of femoral component was also investigated. A significant correlation existed between preoperative flexion, intraoperative flexion, and maximum flexion 1 year postoperatively. Patients who had a preoperative range of flexion less than the mean range of flexion for the overall group gained flexion, whereas patients with a preoperative range of flexion greater than the mean range of flexion lost flexion. The degree of soft tissue release performed and the type of implant used had no influence on maximum flexion at 1 year. The principal predictive factor of postoperative range of flexion, regardless of the degree of soft tissue release or implant design, is the preoperative and intraoperative range of flexion.

Between-day repeatability of knee kinematics during functional tasks recorded using flexible electrogoniometry

The objective of this study was to assess the between-day repeatability of knee kinematics during activities of daily living recorded by electrogoniometry. One rater assessed the peak knee angles and knee excursion of 15 subjects during 13 activities twice with an average of 22 days (range 5-31) between the two assessments. The 15 subjects included four patients one year after total knee replacement (TKR) surgery, five patients before TKR surgery and six age-matched controls. Intra-class correlation coefficients and Bland and Altman coefficient of repeatability were derived to analyse the results. Only the most affected leg of the patients and the right leg of the controls were used for analysis. Different measures of repeatability showed different results. Intra-class correlation coefficients were higher than 0.75 for peak values of all functions except sitting down and rising from a standard chair. However, coefficients of repeatability ranged from 5.6 degrees for the loading response in level walking to 39.8 degrees for stepping out of a bath. Both of these values are higher than clinically significant changes seen after total knee surgery. It was concluded that for a single assessment on individual patients, the functional knee motion as performed in this study did not have sufficient repeatability. However, if the measurements are used to assess the average changes before and after surgery in a group of patients, the assessment of knee motion during activities such as level walking, and slope and stair ascending and descending were found to be sufficiently repeatable.