Background
- The total knee arthroplasty (TKA) is performed on individuals with advanced osteoarthritis resulting in pain and limited function.
- More than 450,000 TKA's are performed in the U.S. each year and this number is expected to double by 2020 (2,69)
- Approximately 40% of patients with unilateral TKA progress to a TKA in the uninvolved knee by 10 years (48,65)
Considerations in Rehabilitation
Muscular Impairments
A post-operative strength deficit of the quadriceps has been well documented in those having undergone a TKA (5,42,52,55,67,70,79,85). This deficit can persist even years after surgery (5,6,29,71,72,85). Patient's produce less thatn half of their preoperative torque at one month post-op (52,54,57,79). Atrophy of 5% to 20% has een reported in the first month as well, compared to pre-operative values (54,62,67). Strength rarely compares to those of healthy age-matched subjects(6,72) or to that of the non-operative knee (5,6,42,52,85). Long-term results show a 30 to 48% strength deficit of the quadriceps compared to healthy age-matched individuals (23,52,53,85). To summarize, strength rapidly declines immediately post-op and then slowly recovers to levels only slighty above pre-operative values (Meier et al, 2008).
Hamstring strength deficits after TKA have also been documented (5,29,42,51,72).
