Does preoperative physiotherapy improve outcomes in patients undergoing total knee arthroplasty? A systematic review

Key points

1. 01Short-term pain reduction and functional gains before surgery are consistently reported in intervention groups
2. 02No study demonstrated a prolonged effect on knee motion or patient function between 3 and 12 months after TKA
3. 03Some studies found reduced hospital length of stay with prehabilitation, though only two of five studies reached statistical significance
4. 04High-intensity progressive resistance training (8 weeks, 3x per week) showed the most consistent early postoperative benefits
5. 05Most included RCTs were small and methodologically moderate to poor quality, limiting definitive conclusions

How it was conducted

Design

Systematic review of 24 randomized controlled trials

Databases searched

MEDLINE/PubMed (1996-05/2021), Embase (1980-05/2021), Cochrane Library, and PEDro (05/2021)

Participants

1499 patients undergoing primary TKA for severe knee osteoarthritis; mean age 62 to 72.8 years

Interventions

Preoperative physiotherapy exercise programs (3 to 12 weeks duration, 2 to 5 sessions per week) including lower limb strengthening, stretching, aerobic training, and balance exercises vs. control (no intervention or usual care)

Primary outcomes

Knee extension strength, knee flexion ROM, pain VAS, WOMAC, 6-minute walk test, and Timed Up and Go test

Quality assessment

PEDro scale (11-item); most RCTs rated moderate to poor quality due to small sample sizes and blinding limitations

What they found

• Of 6 studies using WOMAC, 5 showed no significant improvement in overall WOMAC score or its pain, stiffness, and function subcomponents between groups; 1 study (Calatayud et al., 2017) found significant improvement at all measurement time points
• Of 7 studies using SF-36, 5 showed no significant between-group difference; 2 found greater values in favour of the intervention group on the Physical Functioning subscale
• Of 4 studies using KOOS, 3 found significant differences in favour of the intervention group across all KOOS subscales; 1 found no difference except in the KOOS sport subscale
• Of 5 studies reporting hospital length of stay, 2 showed a significant reduction in favour of the intervention group (Huang et al., 2012 P = 0.0016 for time to achieve 90 degrees knee flexion; Matassi et al., 2014); 3 showed a non-significant trend toward shorter stay
• Of 8 studies measuring lower extremity strength, 4 found no significant between-group difference postoperatively; Skoffer et al. demonstrated improvements in involved leg muscle strength at all test points in the intervention group; Calatayud et al. showed greater knee extension strength at 3 months postoperatively in the intervention group
• All studies failed to show a prolonged effect on knee motion or patient function between 3 and 12 months postoperatively
• PEDro inter-rater reliability ICC = 0.68 (95% CI 0.57, 0.76)

Limitations

• Almost all included RCTs had methodological flaws, particularly regarding allocation concealment and blinding, which is inherent to exercise interventions
• Considerable heterogeneity in intervention type, duration (3 to 12 weeks), frequency (2 to 5 times per week), supervision, and outcome measures prevented robust meta-analysis
• 12 of 24 studies used home-based exercise programs, making compliance with dosage and resistance thresholds difficult to verify
• Control group treatment varied across studies (some received education or physiotherapy, others received no intervention), which may dilute true effect estimates

Why it matters

For patients

Prehabilitation may reduce your pain and help you function better in the weeks immediately before and just after knee replacement, but it is unlikely to change your strength or function at 6 to 12 months compared with not doing it.

For clinicians

Structured preoperative physiotherapy, particularly high-intensity progressive resistance training for at least 8 weeks, can achieve short-term functional gains and may shorten hospital stay, but current evidence does not support a meaningful long-term functional advantage over standard care.

For readers

This review confirms the short-term benefits of prehabilitation are real but transient; future large, well-powered RCTs with standardised protocols are needed before firm recommendations on optimal prehabilitation content and dose can be made.