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Quadriceps Weakness and Osteoarthritis of the Knee

Charles Slemenda, DrPH; Kenneth D. Brandt, MD; Douglas K. Heilman, MS; Steven Mazzuca, PhD; Ethan M. Braunstein, MD; Barry P. Katz, PhD; and Fredric D. Wolinsky, PhD
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From Indiana University School of Medicine, Indianapolis, Indiana.

Acknowledgments: The authors thank Katie Bergan for assistance with data management, Donna Byrd and Brenda Pye for help with patient recruitment and evaluation, and Kathie Lane for secretarial assistance.

Grant Support: In part by grants from the National Institutes of Health Multipurpose Arthritis and Musculoskeletal Diseases Center (2P60AR20582-20) and General Clinical Research Center (PHS M01 RR00750).

Requests for Reprints: Charles Slemenda, DrPH, 702 North Barnhill Drive, Room 135, Indianapolis, IN 46202-5200.

Current Author Addresses: Dr. Slemenda: 702 North Barnhill Drive, Room 135, Indianapolis, IN 46202-5200.

Drs. Brandt and Mazzuca: 492 Clinical Drive, Indianapolis, IN 46202-5103.

Mr. Heilman and Dr. Katz: 699 West Drive, RR 135, Indiana University School of Medicine, Indianapolis, IN 46202-5119.

Dr. Braunstein: Indiana University Medical Center, 550 North University Boulevard, Indianapolis, IN 46202-5253.

Dr. Wolinsky: Regenstrief Institute, 1001 West 10th Street, Indianapolis, IN 46202.

Ann Intern Med. 1997;127(2):97-104. doi:10.7326/0003-4819-127-2-199707150-00001
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Background: The quadriceps weakness commonly associated with osteoarthritis of the knee is widely believed to result from disuse atrophy secondary to pain in the involved joint. However, quadriceps weakness may be an etiologic factor in the development of osteoarthritis.

Objective: To explore the relation between lower-extremity weakness and osteoarthritis of the knee.

Design: Cross-sectional prevalence study.

Setting: Population-based, with recruitment by random-digit dialing.

Participants: 462 volunteers 65 years of age or older.

Measurements: Radiographs of the knee were graded for the presence of osteoarthritis. Knee pain and function were assessed with the Western Ontario and McMaster Universities Arthritis Index, the strength of leg flexors and extensors was assessed with isokinetic dynamometry, and lower-extremity lean tissue mass was assessed with dual-energy x-ray absorptiometry.

Results: Among participants with osteoarthritis, quadriceps weakness, but not hamstring weakness, was common. The ratio of extensor strength to body weight was approximately 20% lower in those with than in those without radiographic osteoarthritis. Notably, among women with tibiofemoral osteoarthritis, extensor weakness was present in the absence of knee pain and was seen in participants with normal lower-extremity lean mass (extensor strength, 30.1 lb-ft for those with osteoarthritis and 34.8 lb-ft for those without osteoarthritis; P < 0.001). After adjustment for body weight, age, and sex, lesser quadriceps strength remained predictive of both radiographic and symptomatic osteoarthritis of the knee (odds ratio for prevalence of osteoarthritis per 10 lb-ft loss of strength, 0.8 [95% CI, 0.71 to 0.90] for radiographic osteoarthritis and 0.71 [CI, 0.51 to 0.87] for symptomatic osteoarthritis).

Conclusion: Quadriceps weakness may be present in patients who have osteoarthritis but do not have knee pain or muscle atrophy; this suggests that the weakness may be due to muscle dysfunction. The data are consistent with the possibility that quadriceps weakness is a primary risk factor for knee pain, disability, and progression of joint damage in persons with osteoarthritis of the knee.

For author affiliations and current author addresses, see end of text.


Grahic Jump Location
Figure 1.
Left leg strength, measured as peak extensor torque at 60 degrees per second, related to sex, topographic localization of radiographic changes of osteoarthritis, and the presence of recent knee pain.

The numbers at the top of each bar represent the mean peak torcue, and the numbers in parertheses represent numbers of participants. Strength was generally greater in the right than in the left leg, but the magnitude of the differences in right leg strength among participants was similar to the magnitude of the differences n left leg strength. OA = osteoarthritis; PF = patellofemoral: TF = tibiofemoral.

Grahic Jump Location




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