Muscle Deficits Persist After Unilateral Knee Replacement and Have Implications for Rehabilitation

Rehabilitation and Pain Unit, Kymenlaakso Central Hospital, FIN-48210 Kotka, Finland.
Physical Therapy (Impact Factor: 2.53). 09/2009; 89(10):1072-9. DOI: 10.2522/ptj.20070295
Source: PubMed


Knee joint arthritis causes pain, decreased range of motion, and mobility limitation. Knee replacement reduces pain effectively. However, people with knee replacement have decreases in muscle strength ("force-generating capacity") of the involved leg and difficulties with walking and other physical activities.
The aim of this cross-sectional study was to determine the extent of deficits in knee extensor and flexor muscle torque and power (ability to perform work over time) and in the extensor muscle cross-sectional area (CSA) after knee joint replacement. In addition, the association of lower-leg muscle deficits with mobility limitations was investigated.
Participants were 29 women and 19 men who were 55 to 75 years old and had undergone unilateral knee replacement surgery an average of 10 months earlier. The maximal torque and power of the knee extensor and flexor muscles were measured with an isokinetic dynamometer. The knee extensor muscle CSA was measured with computed tomography. The symmetry deficit between the knee that underwent replacement surgery ("operated knee") and the knee that did not undergo replacement surgery ("nonoperated knee") was calculated. Maximal walking speed and stair-ascending and stair-descending times were assessed.
The mean deficits in knee extensor and flexor muscle torque and power were between 13% and 27%, and the mean deficit in the extensor muscle CSA was 14%. A larger deficit in knee extension power predicted slower stair-ascending and stair-descending times. This relationship remained unchanged when the power of the nonoperated side and the potential confounding factors were taken into account.
The study sample consisted of people who were relatively healthy and mobile. Some participants had osteoarthritis in the nonoperated knee.
Deficits in muscle torque and power and in the extensor muscle CSA were present 10 months after knee replacement, potentially causing limitations in negotiating stairs. To prevent mobility limitations and disability, deficits in lower-limb power should be considered during rehabilitation after knee replacement.

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Available from: Anu M Valtonen
    • "Quadriceps weakness is one of the main impairments before and also after TKA affecting normal functional activities like walking and stair climbing (Mizner et al., 2005; Vissers et al., 2013). Differences in quadriceps strength between the operated leg (OP) and the nonoperated leg (NOP) become more pronounced immediately after surgery and fail to completely resolve even after several years post surgery (Mizner et al., 2005; Meier et al., 2008; Valtonen et al., 2009; Stevens- Lapsley et al., 2010). These long-lasting differences in strength are also described between TKA patients and age-matched healthy adults (Meier et al., 2008; Stevens-Lapsley et al., 2010). "
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    ABSTRACT: The aim of this study was to monitor the long-term effects of skiing on health-related parameters and implant related factors like loosening and wear in patients with total knee arthroplasty. This paper describes the overall study design, general demographics, and physiological demand of the intervention phase. A control group design consisting of an intervention group (n = 14; age: 70.4 ± 4.5 years) and a control group (n = 17; age: 71.5 ± 5.1 years) was utilized in this study. Parameters of interest were measured during pre-, post-, and retention test sessions. During the 12 weeks of intervention, an average of 25.5 days of guided skiing was conducted by each patient. Daily heart rate (HR) profiles and global positioning system data throughout the ski day were recorded. The intervention group completed an average of 3393 vertical meters of downhill skiing, with a total skiing distance of 33.6 km/day. Average skiing speed was 8.2 m/s. In the skiing phase, the average physiological load was 75.9 ± 6.6% of HRmax . Further effects of the 12-week skiing intervention on the tested parameters will be reported in the following papers of this supplementum. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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    • "Deficits in knee extensor moment are well documented after total knee arthroplasty (TKA) (Mizner et al., 2005;Vissers et al., 2013). Quadriceps muscle strength and associated functional abilities such as walking or stair climbing often fail to reach previous levels, even after several years post-surgery (Meier et al., 2008;Valtonen et al., 2009;Stevens-Lapsley et al., 2010). Beside muscle mass and neuromuscular activation, the generated knee extensor moment of TKA patients seems affected by two main factors: the force–ratio between the quadriceps and the patellar tendon (Browne et al., 2005;Ward et al., 2012) and the patellar tendon moment arm. "

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    • "Although quadriceps muscle strength of TKA patients has been increasingly assessed in the last two decades (Walsh et al., 1998; Mizner et al., 2003; Silva et al., 2003; Valtonen et al., 2009; Swank et al., 2011), there is no consensus among researchers and clinicians regarding the most valid test modality (that is, the modality considered most reliable and best related to physical function). Quadriceps muscle strength of TKA patients has been prevalently assessed during short (3–5 s) static contractions, of which the main outcome is isometric maximal voluntary contraction (MVC) torque (Mizner et al., 2003; Silva et al., 2003), or during slow isokinetic concentric contractions, of which the main outcome is isokinetic peak torque (Walsh et al., 1998; Valtonen et al., 2009; Swank et al., 2011). Isometric and isokinetic testing modalities are generally selected due to their reliability (Kean et al., 2010; Staehli et al., 2010), objectivity and safety, even though their validity has not been amply explored in patients with TKA. "
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    ABSTRACT: The aim of this exploratory study was to verify whether the evaluation of quadriceps muscle weakness is influenced by the testing modality (isometric vs. isokinetic vs. isoinertial) and by the calculation method (within-subject vs. between-subject comparisons) in patients 4-8months after total knee arthroplasty (TKA, n=29) and total hip arthroplasty (THA, n=30), and in healthy controls (n=19). Maximal quadriceps strength was evaluated as (1) the maximal voluntary contraction (MVC) torque during an isometric contraction, (2) the peak torque during an isokinetic contraction, and (3) the one repetition maximum (1-RM) load during an isoinertial contraction. Muscle weakness was calculated as the difference between the involved and the uninvolved side (within-subject comparison) and as the difference between the involved side of patients and controls (between-subject comparison). Muscle weakness estimates were not significantly affected by the calculation method (within-subject vs. between-subject; P>0.05), whereas a significant main effect of testing modality (P<0.05) was observed. Isometric MVC torque provided smaller weakness estimates than isokinetic peak torque (P=0.06) and isoinertial 1-RM load (P=0.008), and the clinical occurrence of weakness (proportion of patients with large strength deficits) was also lower for MVC torque. These results have important implications for the evaluation of quadriceps muscle weakness in TKA and THA patients 4-8months after surgery.
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