Jenkins C1, Jackson W2, Bottomley N2, Price A3,4, Murray D3,4, Barker K1,4
1Oxford University Hospitals NHS Foundation Trust, Physiotherapy Research Unit, Oxford, United Kingdom, 2Oxford University Hospitals NHS Foundation Trust, Orthopaedics, Oxford, United Kingdom, 3Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom, 4Oxford University, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Oxford, United Kingdom

Background: Current practice following knee replacement is to commence flexion promptly in an attempt to limit post-operative stiffness. This can result in increased pain and swelling which in turn limits and delays mobility and discharge. We introduced a new pathway for our knee replacements with an innovative rehabilitation protocol that delayed knee flexion. We hypothesised this would allow earlier mobilisation but have no negative effect on knee range of motion.

Purpose: To evaluate a new protocol of delayed knee flexion.

Methods: In September 2016, an innovative day surgery pathway was introduced. All partial knee replacement patients underwent minimally invasive partial knee replacement surgery. They were mobilised by a physiotherapist, weight bearing as tolerated, on the day of surgery and were discharged home when they were medically well, safe using crutches and stairs and had someone to stay with them for the first 24 hours. For the next 5 days patients were told to keep their knee straight, keep the bulky post-operative bandage on, perform only static quadriceps and foot and ankle circulatory exercises, and walk around inside using crutches. On day 5, they returned to a clinic appointment, their dressings were removed and wounds checked. During the same visit, a physiotherapist reviewed the patients' function and started knee flexion exercises. Active knee flexion and extension was recorded using a long arm goniometer and a programme of functional activity based exercises commenced. Patients were referred for further physiotherapy as required but this was not routine.

Results: Over 18 months, up to February 2018, 669 patients underwent primary unilateral partial knee replacement surgery. At 5 days, the mean fixed flexion was 3.9° (range 0-40) and mean flexion was 78° (range 30-115). At 6 weeks, the mean fixed flexion was 2.8° (range 0-20) and mean flexion 109° (range 60-135). Data collected from a previous cohort using the old protocol, when knee flexion was initiated on day 1 post-operatively, showed mean flexion of 108° at 6 weeks. There was no significant difference in flexion between the two groups (p=0.5). Of the 264 patients discharged on the day of surgery, 1 person (0.4%) returned to theatre for a manipulation under anaesthesia of their knee.

Conclusion(s): We demonstrated that delaying post-operative knee flexion for 5 days produced similar, or better knee flexion at 6 weeks when compared to the previous, more traditional, protocol when knee flexion was initiated on the day after surgery.

Implications: Delaying knee flexion for 5 days post-operatively has no negative effect on knee range of movement at 6 weeks. In conjunction with an enhanced recovery programme, delaying knee flexion allows earlier mobilisation and timely discharge.

Keywords: Partial knee replacement, day surgery, knee flexion

Funding acknowledgements: No external funding

Topic: Musculoskeletal: lower limb; Orthopaedics

Ethics approval required: No
Institution: Oxford University Hospitals NHS Foundation Trust
Ethics committee: Trauma and Orthopaedic Directorate
Reason not required: Reviewed by the directorate governance meeting and deemed to be audit and not requiring formal ethics approval

All authors, affiliations and abstracts have been published as submitted.

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