Summary of Total Knee Arthroplasty
A total knee arthroplasty (TKA) involves the excision of the distal aspect of the femur, the proximal aspect of the tibia, and the posterior aspect of the patella. These surfaces are replaced with metal alloys and plastics with the intention of reducing the pain and disability due to osteoarthritis (OA). Site-specific protocols are the norm for the physical therapy (PT) management of TKA, but the following is a review of the literature in this area.
Guide to PT Practice - Practice Pattern and Suggested Management
Management of TKA falls under Pattern 4H: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated With Joint Arthroplasty in APTA's Guide to Physical Therapist Practice. Treatment for patients within this pattern is expected to last six months and occur continuously over 12-60 visits. The Guide provides an overview of PT management that is in the table below summarized below.
|Therapeutic Exercise||Aerobic capacity/endurance conditioning or reconditioning; Balance, coordination, and agility training; Body mechanics and postural stabilization; Flexibility exercises; Gait and locomotion training; Relaxation; Strength, power, and endurance training for head, neck, limb, pelvic-floor, trunk, and ventilatory muscles|
|Functional Training||//ADL training; Devices and equipment use and training; Functional training programs; IADL training; Injury prevention or reduction; Leisure and play activities and training|
|Manual Therapy||Massage — connective tissue massage, therapeutic massage; Mobilization/Manipulation — soft tissue; Passive Range of Motion|
|Electrotherapeutic Modalities||Biofeedback; Electrical Stimulation — electrical muscle stimulation (EMS), functional electrical stimulation (FES), high voltage pulsed current (HVPS), neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS)|
|Physical Agents and Mechanical Modalities||Cryotherapy — cold packs, ice massage, vapocoolant spray; Hydrotherapy — whirlpool tanks, contrast bath, pool; Sound Agents — phonophoresis, ultrasound; Thermotherapy — dry heat, hot packs, paraffin baths; Mechanical Motion Devices — continuous passive motion (CPM)|
- Impact on pathology/pathophysiology
- Joint swelling, inflammation, or restriction is reduced.
- Nutrient delivery to tissue is increased.
- Osteogenic effects of exercise are maximized.
- Pain is decreased.
- Physiological response to increased oxygen demand is improved.
- Soft tissue swelling, inflammation, or restriction is reduced.
- Tissue perfusion and oxygenation are enhanced.
- Impact on impairments
- Aerobic capacity is increased.
- Airway clearance is improved.
- Balance is improved.
- Endurance is increased.
- Energy expenditure per unit of work is decreased.
- Gait, locomotion, and balance are improved.
- Integumentary integrity is improved.
- Joint integrity and mobility are improved.
- Motor function (motor control and motor learning) is improved.
- Muscle performance (strength, power, and endurance) is increased.
- Postural control is improved.
- Quality and quantity of movement between and across body segments are improved.
- Range of motion is improved.
- Relaxation is increased.
- Sensory awareness is increased.
- Weight-bearing status is improved.
- Impact on functional limitations
- Ability to perform physical actions, tasks, or activities related to self-care, home management, work (job/school/play), community, and leisure is improved.
- Level of supervision required for task performance is decreased.
- Performance of and independence in activities of daily living (ADL) and instrumental activities of daily living (IADL) with or without devices and equipment are increased.
- Tolerance of positions and activities is increased.
- Impact on disabilities
- Ability to assume or resume required self-care, home management, work (job/school/play), community, and leisure roles is improved.
- Risk reduction/prevention
- Preoperative and postoperative complications are reduced.
- Risk factors are reduced.
- Risk of secondary impairment is reduced.
- Safety is improved.
- Self-management of symptoms is improved.
- Impact on health, wellness, and fitness
- Fitness is improved.
- Health status is improved.
- Physical capacity is increased.
- Physical function is improved.
- Impact on societal resources
- Utilization of physical therapy services is optimized.
- Utilization of physical therapy services results in efficient use of health care dollars.
- Patient/client satisfaction
- Access, availability, and services provided are acceptable to patient/client.
- Administrative management of practice is acceptable to patient/client.
- Clinical proficiency of physical therapist is acceptable to patient/client.
- Coordination of care is acceptable to patient/client.
- Cost of health care services is decreased.
- Intensity of care is decreased.
- Interpersonal skills of physical therapist are acceptable to patient/client, family, and significant others.
- Sense of well-being is improved.
- Stressors are decreased.
Cryotherapy (continuous cold flow therapy) is typically used to modulate pain in patients following TKA. Though the evidence is still inconclusive, patients who receive this therapy post-operatively tend to report lower pain scores and decrease their usage of narcotics.
Specific strengthening exercises are not uniformly discussed or agreed upon in the literature. Examples of exercises can be seen in the protocols included at the bottom of the page.
Early application of NMES to the quadriceps has been shown to produce significant strength gains by 3.5 weeks following TKA. The experimental group received a biphasic current with symmetrical waveform, at 50 pps for 15 seconds (including a 3-second ramp up time). Participants were given a 45-second rest period between contractions. They completed 15 contractions per session, twice a day for 6 weeks. Participants were cued to increase the intensity to a level that was uncomfortable, but tolerable.
The addition of aquatic physical therapy to typical PT management in the inpatient setting has been shown to promote greater hip abductor strength when compared to nonspecific water exercise or additional ward physical therapy.
Improving Range of Motion
The latest Cochrane review of continuous passive motion (CPM) following TKA found minimal improvements in ROM for patients with had CPM. The average active and passive knee flexion ROM with CPM was 78 and 84 degrees, respectively, compared to 75 and 82 degrees in patients who did not have CPM.
A 2007 systematic review and meta-analysis of physical therapy exercise following TKA for OA found a small to moderate benefit to increasing knee ROM through functional activities as compared to traditional isometric activities. This effect was noted 3-4 months post-TKA, but there was no difference between groups at 1 year.
Static progressive stretching devices have been shown to be effective in increasing knee flexion and extension ROM in patients presenting with arthrofibrosis following TKA, who have not responded to modalities in standard practice.
Cold compression is the mainstay of decreasing swelling for patients following TKA. Crushed ice is readily available for patient use in the clinic and at home. It has been suggested, though, that the addition of compression as with the Cryo/Cuff is more beneficial in reducing swelling.
It has been suggested that 85% of patients undergoing TKA will regain function regardless of what rehabilitation program is employed. As with strengthening exercises, functional activities have not been largely discussed in the literature. Examples of activities to use with patients can be found in the protocols provided below. Choice of activity should be centered on the individual needs and requirements of the patient.
Home Exercise/Modality Use
There is currently a randomized controlled trial assessing the use of perioperative behavioral modification in the form of telephone reminders to promote adherence to physical therapy activities in patients undergoing TKA. The results of this study have the potential to provide key insights into the effectiveness of behavioral modification in TKA rehabilitation.
As mentioned above, ice is a modality that can be readily used at home. The use of TENS at home has not been discussed in the literature, but could be an option for relieving pain.
Preoperative rehabilitation for TKA has been suggested in the literature. A 2004 systematic review found that preoperative physical therapy was not effective in improving outcome measures in patients undergoing TKA. Since then a 2007 French study recommends at least physical therapy and education to be included in the rehabilitation program. The addition of occupational therapy and patient home visits was also suggested for patients with multiple comorbidities, significant disability, and/or social problems.