Importance of attenuating quadriceps activation deficits after total knee arthroplasty

Abstract

Total knee arthroplasty (TKA) is associated with persistent quadriceps dysfunction. Because quadriceps dysfunction impairs functional performance, minimizing quadriceps dysfunction by attenuating central activation deficits early after surgery may improve function later in life. Rehabilitation strategies incorporating neuromuscular electrical stimulation and early, aggressive quadriceps strengthening may prove beneficial. Furthermore, surgical approaches, such as minimally invasive TKA, may minimize postoperative quadriceps dysfunction.

Figure 1

Schematic of how central activation deficits (CAD) are calculated. a) Using the burst superimposition technique, CAD are determined by the equation: (A/B)*100. b) Using the interpolation technique, CAD are determined by the equation (1-(C/D))*100. The arrows indicate delivery of the electrical stimulus.

Figure 2

Differences in quadriceps strength (A) and central activation deficits (B) between neuromuscular electrical stimulation and control groups. Data are mean±standard deviation. * indicates statistically significant difference in quadriceps strength between groups (P<0.05). [Adapted from (30) PTJ. November 17, 2011; doi: 10.2522/PTJ.201101224; [epub ahead of print], with permission of the American Physical Therapy Association. This material is copyrighted, and any further reproduction or distribution requires written permission from APTA.]

Figure 3

Relation between dose of neuromuscular electrical stimulation treatment and quadriceps strength recovery following anterior cruciate ligament reconstruction. %MVIC=percentage of maximal voluntary contraction. (Reprinted from [Snyder-Mackler L, Delitto A, Stralka SW, Bailey SL. Use of electrical stimulation to enhance recovery of quadriceps femoris muscle force production in patients following anterior cruciate ligament reconstruction. Phys Ther. 1994;74(10):901–7.], with permission of the American Physical Therapy Association. This material is copyrighted, and any further reproduction or distribution requires written permission from APTA.)

Figure 4

Quadriceps strength (A) and central activation deficits (B) following high-intensity and traditional rehabilitation. Data are presented pre-operatively and 3.5, 12, 26, and 52 weeks post-operatively. Data are mean±standard deviation. * indicates statistically significant from pre-operative time point (P<0.05)

Figure 5

Schematic depicting deficits that arise following TKA and potential treatment strategies. TKA leads to functional performance deficits, which are largely attributable to pronounced quadriceps weakness. Quadriceps weakness results from a combination of central activation deficits and muscle atrophy, with activation deficits explaining more of the muscle weakness than atrophy. Quadriceps central activation deficits may be improved through NMES, altered surgical techniques (MIS) and high intensity rehabilitation. Muscle atrophy may also be mitigated effectively by high intensity rehabilitation. Ultimately, a combination of NMES, altered surgical techniques, and high intensity rehabilitation may be most effective in reducing deficits. TKA= total knee arthroplasty; NMES= neuromuscular electrical stimulation; MIS= minimally invasive surgery.