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Titel på arbejdetCoordinated exercise and surgical care of patients with knee osteoarthritis who are eligible for knee replacement: A pragmatic approach (The PREHAB-KR project). Dose-response relationship of pre-operative knee-extensor exercise in patients eligible for knee replacement.
NavnRasmus Skov Husted
Afdeling / StedKlinisk Forskningsafdeling, Amager-Hvidovre Hospital
UniversitetKøbenhavns Universitet
  • Hip and knee surgery
Abstract / Summary

Patients with knee osteoarthritis (OA) suffer from knee pain, a decrease in physical function and quality of life. If the knee OA condition progresses, the patients eventually become eligible for knee replacement to overcome their symptoms. However, international guidelines recommend that non-surgical treatment (e.g. exercise) is tried out before surgical treatment is considered. Physically, the main characteristic of patients with knee OA is decreased knee-extensor muscle strength which is associated with knee OA progression and worsening of symptoms. Following surgery, knee-extensor strength is further decreased, potentially prolonging rehabilitation. It is recognized that exercise treatment focusing on knee-extensor strength is important in patients eligible for knee replacement, however, the optimal knee-extensor exercise dosage is unknown.
When new initiatives are investigated in established organizations, e.g. the health care system, it is important to include stakeholder input to identify potential facilitators and barriers to adjust the initiative under study.

The objectives of this PhD thesis were 1) to investigate the knee-extensor dose-response relationship before and after total knee arthroplasty in patients scheduled for surgery (systematic review, study I), 2) to investigate the dose-response relationship of three different home-based knee-extensor exercise dosages of one knee-extensor exercise before and after knee replacement in patients eligible for surgery. Further, to investigate this in an intersectoral model of coordinated non-surgical and surgical care (the QUADX-1 trial, study II+III) and 3) to identify perceived facilitators and barriers among physiotherapists and orthopedic surgeons towards coordinated non-surgical and surgical care with one home-based exercise in patients eligible for knee replacement (qualitative, study IV).

Study I (systematic review)
Twelve trials with 616 patients were included. Meta-regression analysis showed no relationship between pre-operative knee-extensor exercise dosage and change in knee-extensor strength neither prior to (slope 0.0005 [95%CI -0.007 to 0.008]) or three months following knee replacement (slope 0.0014 [95%CI -0.006 to 0.009]). Before knee replacement, a moderate effect favoring pre-operative exercise for an increase in knee-extensor strength was found (SMD 0.50 [95%CI 0.12 to 0.88]), but not three months after knee replacement (SMD -0.01 [95%CI -0.45 to 0.43]).

Study II+III (QUADX-1 trial)
One-hundred and forty patients eligible for knee replacement were included and randomized to 12 weeks of knee-extensor exercise with either exercise dosage ‘2 session/week’, ‘4 session/week’ or ‘6 sessions/week’. The dosages are referred to as group A, B and C as the trial was not unblinded for the thesis. Assessment of the primary outcome (after exercise) was completed for 117 patients. For the intention-to-treat analysis, 140 patients were included. For the primary outcome isometric knee-extensor strength (Nm/kg) no dose-response relationship was observed between the three groups after 12 weeks of exercise – group B vs. A (0.04 [95% CI -0.13 to 0.20], p=0.6685), group C vs. A (0.009 [95% CI -0.15 to 0.17], p=0.9131) and group C vs. B [-0.03 (95% CI -0.18 to 0.13], p=0.7253). For the secondary outcomes, significant differences in change from baseline to after 12 weeks of exercise was found between group C and B for Oxford Knee Score (4.2 [95% CI 0.6 to 7.8], p=0.0216) and average knee pain last week (NRS 0-10) (-1.1 [95% -2.2 to -0.1], p=0.0303). No between group difference was observed for any other group comparisons or secondary outcomes at the primary end-point. Within group changes showed a positive change for the whole sample and all three groups separately. Larger changes were observed for group C compared to group A and B, and group A compared to group B. Of the 117 patients with assessments after 12 weeks of exercise, 79 (67.5%) postponed surgery, 32 (27.4%) underwent surgery and 6 (5.1%) wanted surgery but this was contraindicated.

Study IV (qualitative)
Four orthopedic surgeons and six physiotherapists were included and interviewed with single- and focus group interviews, respectively. The thematic analysis showed that the pre-operative exercise intervention created ambivalence in the professional role of both the physiotherapists and orthopedic surgeons. The physiotherapists were positive towards supporting patient self-management but skeptical towards a too simplified exercise therapy. The orthopedic surgeons were positive towards having exercise as a treatment option but skeptical towards the potential lack of (long-term) effect of exercise in patients eligible for knee replacement.

In conclusion, results from the systematic review and the QUADX-1 trial show no clear dose-response relationship between pre-operative knee-extensor exercise dosage and change in outcomes before or after surgery in patients eligible for knee replacement. The results indicate that pre-operative knee-extensor strengthening exercise improves outcomes before surgery in patients eligible for knee replacement. Results from the QUADX-1 trial supports the effect of one exercise-only knee-extensor exercise before potential surgery in patients eligible for knee replacement with improvement in e.g. the cardinal symptom knee pain. This improvement in outcomes before surgery was independent of prescribed exercise dosage, however there was a tendency for dosage C to be superior to dosage B. In the imbedded qualitative study, we found that the pre-operative one exercise-only intervention was associated with barriers creating ambivalence in the professional role of both the physiotherapists and the orthopedic surgeons. These barriers and associated ambivalence in the professional role are important to consider when evaluating the coordinated non-surgical and surgical care pathway.

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