Early strength response of the knee extensors during eight weeks of resistive training after unilateral total knee arthroplasty

Improvement in hamstring and quadriceps muscle strength following cruciate-retaining single radius total knee arthroplasty

Background

The ability to reach full functional capacity following total knee arthroplasty (TKA) is reliant on the strength of the quadriceps and hamstring muscles. Weakness of these muscles can persist anywhere from 1 to 3 years post-operatively. There remains considerable controversy as to what factors influence restoration of muscle strength after TKA. Implant designs have been implicated in the ability of patients to recover. Currently there is a paucity of literature available describing the influence of patient characteristics, surgical factors, and clinical outcomes on quadriceps and hamstring muscle strength following TKA with a cruciate-retaining, single radius (SR) implant. For this reason, we sought to investigate TKA patients for: (I) quadriceps muscle strength; (II) hamstring muscle strength; (III) flexion/extension (F/E) ratio; (IV) clinical outcome scores; (V) influence of patient characteristics on muscle strength at one-year post-operatively.

Methods

A review of TKA patients who were assessed for hamstring and quadriceps muscle strength was conducted. A total of 39 patients (26 men and 13 women), who had a mean age of 68 years (range, 51 to 88 years) were included. Isokinetic dynamometer testing at 180 degree/second for 3 sets of 10 repetitions in extension and flexion were performed by an independent physical therapist to assess dynamic concentric torque of the hamstrings and quadriceps muscle. F/E ratios were calculated. TKA was performed via subvastus (n=20) or midvastus (n=19) approach. Subgroup analysis for surgical approach, concomitant spinal pathology (n=11), gender, age and body mass index (BMI) were performed. Knee Society Scores (KSS) and range of motion (ROM) were assessed at each visit. Comparisons of groups were performed using paired t-tests.

Results

Mean postoperative relative extension torque was 23 Nm/kg (range, 9 to 43 Nm/kg), representing a mean increase of 38% (range, -16% to 100%; P=0.0267) from pre-operative status. A mean increase of 27% (range, -15% to 100%; P=0.0433) in flexion strength and mean relative flexion torque of 19 Nm/kg (range, 8-37 Nm/kg) was observed. Pre-operative mean F/E ratio was 0.8 and 0.9 post-operatively (P=0.3028). Men demonstrated significantly greater improvements in flexion compared to women (22% vs. 12%; P<0.0001), but gender had no influence on improvement in extension (27% vs. 15%; P=0.0537). Postoperative F/E was similar for males (0.8) and females (0.9; P=0.4454). Surgical approach did not influence quadriceps muscle strength (P=0.1786) or hamstrings muscle strength (P=0.9592). History of spine pathology had no impact on muscles strength (hamstring, P=0.5684; quadriceps, P=0.7221). For the overall group, a mean KSS pain score was 96 points (range, 84 to 100 points), KSS function was 96 points (range, 80 to 100 points), and mean ROM of 0 to 114 degrees.

Conclusions

Restoration of quadriceps and hamstring muscle strength can be expected at 1 year post-operatively regardless of gender, surgical approach or concomitant spinal pathology. Further comparative investigation on the impact of implant design on hamstring and quadriceps muscle strength is warranted. However, the use of a SR, CR TKA system demonstrated significant improvements post-operatively in quadriceps and hamstring strength.

Mechanisms of quadriceps muscle weakness in knee joint osteoarthritis: the effects of prolonged vibration on torque and muscle activation in osteoarthritic and healthy control subjects

INTRODUCTION

A consequence of knee joint osteoarthritis (OA) is an inability to fully activate the quadriceps muscles, a problem termed arthrogenic muscle inhibition (AMI). AMI leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. The purpose of the present study was to determine whether γ-loop dysfunction contributes to AMI in people with knee joint OA.

METHODS

Fifteen subjects with knee joint OA and 15 controls with no history of knee joint pathology participated in this study. Quadriceps and hamstrings peak isometric torque (Nm) and electromyography (EMG) amplitude were collected before and after 20 minutes of 50 Hz vibration applied to the infrapatellar tendon. Between-group differences in pre-vibration torque were analysed using a one-way analysis of covariance, with age, gender and body mass (kg) as the covariates. If the γ-loop is intact, vibration should decrease torque and EMG levels in the target muscle; if dysfunctional, then torque and EMG levels should not change following vibration. One-sample t tests were thus undertaken to analyse whether percentage changes in torque and EMG differed from zero after vibration in each group. In addition, analyses of covariance were utilised to analyse between-group differences in the percentage changes in torque and EMG following vibration.

RESULTS

Pre-vibration quadriceps torque was significantly lower in the OA group compared with the control group (P = 0.005). Following tendon vibration, quadriceps torque (P < 0.001) and EMG amplitude (P ≤0.001) decreased significantly in the control group but did not change in the OA group (all P > 0.299). Hamstrings torque and EMG amplitude were unchanged in both groups (all P > 0.204). The vibration-induced changes in quadriceps torque and EMG were significantly different between the OA and control groups (all P < 0.011). No between-group differences were observed for the change in hamstrings torque or EMG (all P > 0.554).

CONCLUSIONS

γ-loop dysfunction may contribute to AMI in individuals with knee joint OA, partially explaining the marked quadriceps weakness and atrophy that is often observed in this population.

Anabolic steroids after total knee arthroplasty. A double blinded prospective pilot study

Background

Total knee arthroplasty is reported to improve the patient's quality of life and mobility. However loss of mobility and pain prior to surgery often results in disuse atrophy of muscle. As a consequence the baseline functional state prior to surgery may result in poorer outcome "post surgery" and extended rehabilitation may be required. The use of anabolic steroids for performance enhancement and to influence muscle mass is well established. The positive effects of such treatment on bone and muscle could therefore be beneficial in the rehabilitation of elderly patients. The purpose of this study was to investigate the effects of small doses of Nandrolone decanoate on recovery and muscle strength after total knee replacement and to establish the safety of this drug in multimorbid patients.

Methods

This study was designed as a prospective double blind randomized investigation. Five patients (treatment group) with a mean age of 66.2 (58-72), average BMI of 30.76 (24.3-35.3) received 50 mg nandrolone decanoate intramuscular bi-weekly for 6 months. The control group (five patients; mean age 65.2, range 59-72; average BMI 31.7, range 21.2-35.2) was injected with saline solution. "Pre-operatively" and "post-operatively" (6 weeks, 3,6,9 and 12 months) all patients were assessed using the knee society score (KSS), isokinetic strength testing and functional tests (a sit-to-stand and timed walking tests). In addition, a bone density scan was used preoperatively and 6 month postoperatively to assess bone mineral density.

Results

Whilst the steroid group generally performed better than the placebo group for all of the functional tests, ANOVA failed to reveal any significant differences. The steroid group demonstrated higher levels of quadriceps muscle strength across the postoperative period which reached significance at 3 (p = 0.02), 6 (p = 0.01), and 12 months (p = 0.02). There was a significant difference for the KSS at 6 weeks (p = 0.02), 6 (p = 0.02) and 12 month (p = 0.01). The steroid group demonstrated a reduction in the amount of bone mineral density at both the femur and lumbar spine from "pre-" to "post-surgery", however, these results did not reach significance (p < 0.05) using one-way ANOVA.

Conclusions

This project strongly suggests that the use of anabolic steroids result in an improved outcome as assessed by the KSS and significantly increases extensor strength. No side effects were seen in either the study or control group.

Trial Registration Number

Regional Health District: Register No. 03.05

Human Research Ethics Committee University: Clearance Number: 04/03-19

Surface neuromuscular electrical stimulation for quadriceps strengthening pre and post total knee replacement

BACKGROUND

Total knee replacement has been demonstrated to be one of the most successful procedures in the treatment of osteoarthritis. However quadriceps weakness and reductions in function are commonly reported following surgery. Recently Neuromuscular Electrical Stimulation (NMES) has been used as an adjunct to traditional strengthening programmes. This review considers the effectiveness of NMES as a means of increasing quadriceps strength in patients before and after total knee replacement.

OBJECTIVES

To assess the effectiveness of NMES as a means of improving quadriceps strength before and after total knee replacement.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1950 to January week 1 2008), EMBASE (1980 to 2008 week 2), Cumulative Index to Nursing and Allied Health Literature (CINAHL)(1982 to 2007/11), AMED (1985 to Jan 2008), Web of Science, and Pedro (Jan 2008) (http://www.pedro.fhs.usyd.edu.au/index.html) for randomised controlled trials and controlled clinical trials. The electronic search was complimented by hand searches and experts in the area and companies supplying NMES equipment were also contacted.

SELECTION CRITERIA

Randomised controlled trials and controlled clinical trials were accepted that used NMES for the purpose of quadriceps strengthening either pre or post total knee replacement.

DATA COLLECTION AND ANALYSIS

Two review authors decided which studies were suitable for inclusion based on the inclusion and exclusion criteria in the protocol and the data was extracted using pre-developed data extraction forms. Two review authors (BM and BC) independently assessed the methodological quality of the included trials using a descriptive approach as advocated by the Musculoskeletal group. Only two studies were included in the review. Neither study presented results in a form suitable for meta-analysis. The authors of both studies were contacted to obtain the raw data but they were no longer available.The data from both studies are described in the review.

MAIN RESULTS

Two studies were identified for inclusion in the review. No significant differences were reported in either study for maximum voluntary isometric torque or endurance between the NMES group and the control group but significantly better quadriceps muscle activation was reported in the exercise and neuromuscular stimulation group compared with the exercise group alone in the second study. This difference was significant at the mid training (six week) time point but not at the twelfth week post training time point. Further analysis of both studies were not possible due to the absence of raw data scores. Both studies carried a high risk of bias. Mean values were not given for strength, endurance, cross sectional area or quality of life. Pain outcomes, patient satisfaction or adverse effects were not reported in either study. The results were presented as percentage improvements from baseline and the number of subjects in each group was unclear.

AUTHORS' CONCLUSIONS

The studies found in this review do not permit any conclusions to be made about the application of neuromuscular stimulation for the purposes of quadriceps strengthening before or after total knee replacement. At this time the evidence for the use of neuromuscular stimulation for the purposes of quadriceps strengthening in this patient group is unclear.