Christensen et al’s 2018 study illustrates the different factors that contribute to optimal outcomes following total knee arthroplasty. To achieve optimal results any grouping of interventions is required in order to deliver outcomes in 4 outcomes domains:
1) Symptom moderation
2) Impairment correction
3) Subjective functional performance
4) Objective functional performance
There is only modest association between the different outcome domains, with stronger association between the impairment and the objective performance domains.
The article investigated the contribution of quadriceps strength and limb symmetry index (impairment) to biomechanical metrics during a descending walking task (objective functional performance) and concludes that: “Persistent quadriceps weakness is a key factor associated with walking compensation patterns that are limiting the capacity for greater physical performance of patients with TKA.”
The article further illustrates the need for precision design and dosing of therapeutic interventions to optimally improve all factors of the impairment domain: range of motion, sensory-neuro-motor-control, and neuro-muscular performance.
Christensen JC, Mizner RL, Foreman KB, Marcus RL, Pelt CE, LaStayo PC. Quadriceps weakness preferentially predicts detrimental gait compensations among common impairments after total knee arthroplasty. J Orthop Res. 2018 Mar 25. doi: 10.1002/jor.23894