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Electromyographic predictors of residual quadriceps muscle weakness after anterior cruciate ligament reconstruction
by
McHugh MP, Tyler TF, Browne MG, Gleim GW, Nicholas SJ.
—
last modified
2009-10-09 15:16
Am J Sports Med. 2002 May-Jun;30(3):334-9.
BACKGROUND: Despite the high prevalence of residual quadriceps muscle weakness
after anterior cruciate ligament reconstruction, specific predictive factors have
not been identified. HYPOTHESIS: Electromyographic analysis is a better predictor
of residual muscle weakness than is preoperative strength. STUDY DESIGN:
Prospective cohort study. METHODS: The quadriceps muscle strength of 37 patients
(25 men, 12 women) was measured before reconstruction and 5 weeks and 6 months
after surgery. Quadriceps surface electromyographic signals were recorded during
all of the strength tests. Integrated electromyographic analysis and median
frequency measurements were computed as deficits on the involved side. Patients
also performed a single-legged hop test at the 6-month follow-up examination.
RESULTS: The patients had significantly lower strength, integrated
electromyographic analysis, and median frequency measurements on the involved
side at all three time intervals. The best predictor of the quadriceps muscle
strength deficit at 6 months was the combination of the preoperative median
frequency deficit and the 5-week postoperative strength deficit. The best
predictor of the hop test deficit at 6 months was the combination of preoperative
deficits in integrated electromyographic analysis and median frequency.
CONCLUSION: Preoperative electromyographic indices of quadriceps muscle function
and early postoperative strength were predictive of residual weakness and
impaired function 6 months after reconstruction.