Michelle M. McLeod, Phillip Gribble, Kate R. Pfile and Brian G. Pietrosimone
Arthroscopic partial meniscectomy (APM) after meniscal tear has been widely accepted and associated with quick return to activity. Unfortunately, meniscectomy is associated with risk for knee osteoarthritis, which may be attributed to postsurgical quadriceps weakness. This has important implications, as the quadriceps play a prominent role in knee stabilization and energy attenuation in the lower extremity.
To determine the magnitude of interlimb quadriceps strength deficits in people with unilateral APM by systematically reviewing the current literature.
The Web of Knowledge databases were searched on September 22, 2010, using terms meniscus OR meniscectomy AND quadriceps strength OR quadriceps weakness. Included articles were written in English, reporting means and SDs of isokinetic peak torque at 60° and 180°/s for both limbs.
Four articles were included in the final analysis. Effect sizes and 95% confidence intervals (CI) were calculated between limbs for periods less than 1 mo, 1–3 mo, 3–6 mo, and more than 6 mo.
Homogeneous effect sizes indicate quadriceps weakness in the involved limb. Effects were strong at less than 1 mo (d = −1.01 to −1.62), while weak to strong effects were found for 1–3 mo (d = −0.40 to −8.04) and 3–6 mo (d = −0.40 to −5.11). Weak effects were found at more than 6 mo (d = −0.30 to −0.37). Definitive effects with a CI not crossing zero were found in 65% of the data. Although APM patients return to function within weeks after surgery, prolonged quadriceps strength deficits may increase the risk of knee-joint degeneration. Furthermore, evidence of bilateral dysfunction after unilateral injury may suggest that neuromuscular deficits post-APM are greater than the interlimb differences found in this review. Further research should be conducted to determine the nature of strength deficits and the best methods for restoring strength after APM.
Matthew Harkey, Michelle M. McLeod, Masafumi Terada, Phillip A. Gribble and Brian G. Pietrosimone
Spinal-reflexive and corticomotor excitability may have a critical role in altering muscle function needed to stabilize the ankle in people with chronic ankle instability (CAI).
To determine the association between self-reported disability and both spinal-reflexive and corticomotor excitability in people with CAI.
Descriptive laboratory study.
30 participants with CAI.
Main Outcome Measures:
Soleus spinal-reflexive excitability was measured with normalized Hoffmann reflexes (H:M ratio), and corticomotor excitability was measured with transcranial magnetic stimulation and quantified by normalized motor-evoked-potential (MEP) amplitudes at 120% of active motor threshold (120%MEP). Self-reported disability was quantified with the activities-of-daily-living and sport subscales of the Foot and Ankle Ability Measure (FAAM-ADL and FAAM-S). Separate linear Pearson product–moment correlations and nonlinear quadratic correlations were used to determine associations between the neural-excitability and disability variables.
Thirty participants were included in the spinal-reflexive-excitability analysis, while only 19 were included in the corticomotor analysis. There was a significant, weak linear association between H:M ratio and FAAM-ADL (R = .39, P = .03) and a nonsignificant, weak linear association between H:M ratio and FAAM-S (R = .36, P = .06). There were significant, moderate quadratic associations between H:M ratio and both FAAM-ADL (R = .48, P = .03) and FAAM-S (R = .50, P = .02). There was a significant, moderate linear association between 120%MEP and FAAM-ADL (R = –.48, P = .04) and a nonsignificant, moderate negative linear association between FAAM-S (R = –.42, P = .07). There was a significant, moderate quadratic association between 120%MEP and FAAM-ADL (R = .57, P = .046) and a significant, strong quadratic correlation between 120%MEP and FAAM-S (R = .71, P = .004).
There are significant quadratic associations between self-reported disability and both spinal-reflexive and corticomotor excitability of the soleus. CAI participants with low or high neural excitability present with lower function.