Hamilton DF, McLeish JA, Gaston P, Simpson AHRW. Muscle 'regenerative potential' determinesphysical recovery following total knee replacement.
Bone Joint Res 2013;
2:70-8. [PMID:
23673375 PMCID:
PMC3638306 DOI:
10.1302/2046-3758.24.2000151]
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Abstract
Objectives
Lower limb muscle power is thought to influence outcome following
total knee replacement (TKR). Post-operative deficits in muscle
strength are commonly reported, although not explained. We hypothesised
that post-operative recovery of lower limb muscle power would be
influenced by the number of satellite cells in the quadriceps muscle at
time of surgery.
Methods
Biopsies were obtained from 29 patients undergoing TKR. Power
output was assessed pre-operatively and at six and 26 weeks post-operatively
with a Leg Extensor Power Rig and data were scaled for body weight.
Satellite cell content was assessed in two separate analyses, the
first cohort (n = 18) using immunohistochemistry and the second
(n = 11) by a new quantitative polymerase chain reaction (q-PCR)
protocol for Pax-7 (generic satellite cell marker) and Neural Cell
Adhesion Molecule (NCAM; marker of activated cells).
Results
A significant improvement in power output was observed post-operatively
with a mean improvement of 19.7 W (95% confidence interval (CI)
14.43 to 30.07; p < 0.001) in the first cohort and 27.5 W (95%
CI 13.2 to 41.9; p = 0.002) in the second. A strong correlation
was noted between satellite cell number (immunohistochemistry) and improvement
in patient power output (r = 0.64, p = 0.008). Strong correlation
was also observed between the expression of Pax-7 and power output
(r = 0.79, p = 0.004), and the expression of NCAM and power output
(r = 0.84, p = 0.001). The generic marker explained 58% of the variation
in power output, and the marker of activated cells 67%.
Conclusions
Muscle satellite cell content may determine improvement in lower
limb power generation (and thus function) following TKR.
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