Persistent Muscle Deficits Following Unilateral Knee Replacement

Knee joint replacement has been an effective surgery for reducing pain in persons with knee joint arthritis. Although function tends to return to preoperative levels within 2 months after surgery, people with knee replacements continue to have limitations in mobility that include lower maximum walking speeds and slower speeds during stair negotiation.

Side-to-side asymmetry in muscle strength (force-generating capacity) and muscle power (ability to perform work), as well as a loss f cross-sectional area (CSA), have been associated with limitations in this population; however, the persistence of these deficits repersistence of these deficits remains unknown. Valtonen et al from the university of Jyvaskyla, Finland, determined the extent of knee muscle strength and power deficits, along with knee extensor CSA in a group of people who had undergone unilateral knee replacement approximately 10 months earlier.

Forty-eight volunteers (29 women and 19 men) ages between 55 and 75 years who had undergone unilateral knee replacement surgery an average of 9.4 months earlier participated. Knee extensor and flexor muscle torque and power were assessed using an isokinetic dynamometer; CSA of the knee extensors was evaluated using computed tomography. Maximal walking speed over 10 meters and timed stair ascent/descent measured mobility.

The results of this study showed signicantly lower strength and power on the operated side when compared with the nonoperated side. The knee extensor torque and power deficits were 27% and 23%, respectively. Knee flexor measures were also significantly lower for the operated side (13% for torque and 19% for power). The knee extensor muscle CSA in the operated leg was 14% smaller than in the nonoperated leg. It is also important to note that a reduction in knee extensor power was predictive of slower times during stair negotiation.

The findings of this study have significant implications for rehabilitation programs. Even through function may return to preoperative levels, this study showed that side-to-side deficits persist. These deficits, particularly knee extensor power deficits, have been linked to increased risk of fall in prior studies. Increasing knee muscle power should be one of the central issues to address during rehabilitation programs.

Valtonen A, Poyhonen T, Heinonen A, Sipila S. Muscle deficits persist after unilateral knee replacement and have implications for rehabilitation. Phys Ther 2009;89:1072-1079.

Two Nonoperative Approaches for Plantar Heel Pain

Every year nearly 2 million Americans will develop plantar heel pain, defined as pain along the medial border of the plantar fascia to its insertion at the medial calcaneal tubercle. Classic symptoms include pain with the first few steps in the morning, after prolonged sitting or with increased intensity of activity. Plantar heel pain can lead to considerable functional limitation and is a common condition seen by physical therapists.

Many interventions are used to treat plantar heel pain and include modalities such as iontophoresis, ultrasound, cryotherapy, stretching and strengthing, manual therapy. Evidence as to the effectiveness of these interventions has varied from weak to moderate, thus making it challenging to establish a consensus on the optimal physical therapy regime for patients with heel pain.

In this international multicenter randomized clinical trial, Cleland et al from Franklin Pierce University, New Hampshire, assessed the effect of 2 different conservative treatment approaches for plantar heel pain. Sixty patients between ages 18 and 60 years (mean age, 48.4 years) who presented to outpatient physical therapy clinics with a primary diagnosis of plantar heel pain were randomly assigned to either an electrophysical agents and exercise (EPAX) treatment group or a manual physical therapy and exercise (MTEX) group. Table 1 describes the treatments for each group.


Patients were assessed at baseline, at the end of 4 weeks of intervention and at 6 months. The primary outcome measure used to assess the patients' perceived level of disability as a result of their plantar heel pain was the Lower Extremity Functional Scale (LEFS) this scale consists of 20 questions with a highest possible score of 80, indicating greater levels of function. Additional outcome measures included the following:

• Foot and Ankle Ability Measure

* Numeric Pain Rating Scale (NPRS)

The results of this study showed both results of this study showed both approaches demonstrated benefits; however, the magnitude of benefit was enhanced in the MTEX group. The MTEX group experienced both significantly greater and clinically meaningful improvements in disability and pain over the EPAX group in their LEFS at both the 4 week and 6 month follow-ups (Figure 1). The MTEX group also reported significantly better outcomes for pain intensity, reported at 4 weeks, although at 6 months these groups demonstrated no difference in their reports of pain intensity as measured by the NPRS.



MTEX showed greatest differences in outcome at 4 weeks compared with a treatment intervention that included EPAX. This approach offers a viable and effective alternative to nonoperative intervention for plantar heel pain. Future studies should compare the effectiveness of this approach to other traditional interventions, such as night splints and orthotics, for planter heel pain.

Cleland JA, Abbott JH, Kidd MO, et al. Manual physical therapy and exercise versus electrophysical agents and exercise in the management of plantar heel pain: a multicenter randomized clinical trial. J Orthop Sports Phys Ther 2009;39:573-585.

Kinesio Taping for Acute Whiplash Injury

Whiplash injuries or whiplash-associated disorders (WADs) can result in significant pain and disability that persist beyond the acute period of injury. Kinesio Taping is a passive intervention that has become increasing popular as an adjunctive intervention for conditions such as patellar dislocation, ankle instability and shoulder pain.

The therapeutic mechanisms of Kinesio Taping are not known but may include factors such as increased afferent stimulation, range of motion (ROM) limitation and enhanced local circulation. This study by Gonzalez-Iglesias et al from Centro de Fisioterapia Integral, Spain, examined whether Kinesio Taping may be beneficial to reduce pain and improve cervical ROM in patients with acute WAD.

Forty-one patients diagnosed with WAD (neck pain symptoms and musculoskeletal signs of restricted ROM) secondary to a motor-vehicle accident within the previous 40 days participated. The patients had a mean age of 33 + 7 years and 52% were female. Patients were randomized into 1 of 2 groups: the experimental group (n + 21) received Kinesio aping to the cervical spine applied with tension to the posterior neck structures; the placebo group (n + 20) received a sham Kinesio Taping application applied without tension.

Patients were evaluated at baseline, immediately following tapping application and 24 hours following. Both patients and assessors were blinded to the patients allocation group. The outcome variables assessed included a 10-point Numerical Pain Rating Scale (NRS) and cervical ROM measurements.

The study found that the patients who received the Kinesio Taping had significantly greater improvements in neck pain both immediately after the tape was applied and at the 24-hour follow-up compared with the sham treatment group. At the 24-hour follow-up, the difference between groups in cervical ROM measurements ranged from 2.3° to 8.5°, with greater motion in the Kinesio Taping group. Although the changes were statistically significant, the authors noted that these changes were small and might not exceed differences that would be considered clinically meaningful to patients.

Although the findings of this preliminary study were limited to short-term benefits, there is the potential that Kinesio Taping may enhance outcomes when added to physical therapy interventions with proven efficacy for WAD such as active exercise. Further study is warranted to determine the long-term benefits of Kinesio Taping.

Gonzales-Iglesias J, Fernandez-de-las-Penas C, Cleland J, et al. Short-term effects of cervical range of motion in patients with acute whiplash injury: a randomized clinical trial. J Orthop Sports Phys Ther 2009;39:515-521.

Feedback Training and Strengthening Positively Affect Movement Patterns

Altered lower extremity movement patterns have been linked to the high occurrence of anterior cruciate ligament (ACL) injuries in women. The landing phase of the stop-jump task is particularly problematic, because the large majority of noncontact injuries occur during this maneuver.

Herman et al from the University of North Carolina at Chapel Hill assessed (1) the effects of instructional videotape feedback on jump-landing mechanics and (2) the effects of a strengthening program with feedback to enhance jump-landing techniques. Assessed variables included tibial anterior shear force, vertical ground reaction force, and knee and hip angular motion and moments.

Fifty-eight healthy female recreational athletes between ages 18 and 30 years were randomized into 2 groups. Participants in the strength training and feedback (ST-FB) group engaged in 9 weeks of strength training intervention prior to completing a jump-landing feedback instruction protocol. The feedback (FB)-only group received the same feedback training protocol as the ST-FB group including a checklist to aid in the evaluation of their technique (Table 2) as well as 3 feedback sessions. Hip and knee joint angles as well as resultant forces and moments were determined.

The group that completed strength training showed significant increases in strength in all muscles analyzed (quadriceps, gluteus medius and maximus, and hamstrings) with strength increases ranging from 37% to 51%. Following biofeedback training, both groups were able to positively alter lower limb mechanics during the stop-jump task. For both groups, these changes included a reduction in peak vertical ground reaction force, decreased knee valgus and hip abduction moment, and increased knee and hip flexion. However, the modifications following feedback were enhanced in the group that also completed the strengthening protocol. The ST-FB group demonstrated decreased knee anterior shear and increased hip abduction angle.

The changes in movement patterns following feedback resulted in improved jump-landing techniques that may help minimize ACL injury risk. The authors suggested that the ability to control movement patterns was improved by providing strength gains in the key lower extremity muscles used during this task. This study provides the necessary first step in the development of preventative programs for ACL injuries that incorporate a multimodal approach, including strength training and video-assisted feedback to improve jump-landing strategies.

Herman DC, Onate JA, Weinhold PS, et al. The effects of feedback with and without strength training on lower extremity biomechanics. Am J Sports Med 2009;37:1301-1308.

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