The Light Knee Study: The effects of light therapy on post-operative pain and functional mobility in people undergoing knee replacement surgery.

INTERVENTION: The intervention is photobiomodulation (PBM) or light therapy applied using a novel light patch system. CareWear is a novel, 3‐D printed self‐adhesive patch with hundreds of micro‐diodes (light emitting diodes are found in many home appliances) that emit specific light frequencies that have been found in other research to reduce inflammation and pain. The CareWear patch is registered in the USA and with the Australian Therapeutic Goods Administration (TGA) for applying light to areas of pain and inflammation. The effectiveness of the light patches will be compared to sham light patches. Consenting participants will be loaned a CareWear kit and visited at home to be shown how to apply the light patches to the knee to be operated on. Whether in the sham (inactive) group or the active intervention group, the light patch treatment period lasts for 3 weeks commencing the week before the participants' scheduled surgery, and for the two weeks following knee replacement surgery. Regardless of which group participants are randomly assigned to, they will continue to be seen for follow‐up appointments, and will be asked to complete all tests and questionnaires, as described. Participants will be visited at home one week before scheduled surgery, one day before the surgery, and at one week, two weeks, four weeks, and six weeks after knee replacement surgery; and again at 6 months and 12 months after surgery. Participants will also be seen in hospital on Day 4 after surgery when they would normally be expected to be discharged from hospital. Participants will be shown how to self‐apply the patches to standardised positions over the large muscle at the front of the thigh, behind the knee, and above and below the knee at each treatment; and remove the patches following e CONDITION: Knee osteoarthritis;Total knee arthroplasty; ; Knee osteoarthritis ; Total knee arthroplasty Musculoskeletal ‐ Osteoarthritis Surgery ‐ Other surgery PRIMARY OUTCOME: Change in numeric pain rating scale (NPRS)[Baseline one week prior to knee replacement surgery; One day prior to knee replacement surgery; Day 4 post‐operation; 1 week post‐operation (primary timepoint); 2 weeks post‐operation; 4 weeks post‐operation; 6 weeks post‐operation; 6 months post‐operation; 12 months post‐operation] SECONDARY OUTCOME: 30 second Timed Stands (chair stand) test to assess physical function, dynamic balance and pain[Baseline one week prior to knee replacement surgery ; One day prior to knee replacement surgery ; Day 4 post‐operation ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] 40m fast‐paced walk test to assess pain, walking speed over a short distance, and changing direction whilst walking[Baseline one week prior to knee replacement surgery ; One day prior to knee replacement surgery ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] Analgesic use (for morphine equivalency): ; ‐ during at home period, patients will record analgesic use in a study diary ; ‐ during hospital in‐patient period, morphine‐equivalent concentrations will be extracted and recorded from the participant’s medical record[Baseline one week prior to knee replacement surgery ; One day prior to knee replacement surgery ; Day 4 post‐operation ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] Exploratory analysis of bone, synovial membrane and synovial fluid samples is a composite secondary outcome for investigating: ; ‐ inflammatory cytokines (most likely IL‐1 and IL‐6) ; ‐ histology using simple haematoxylin and eosin (H&E) staining for evidence of basic tissue morphology, inflammatory cell infiltrate, fibrosis / necrosis, bone erosion, osteoblasts and osteoclasts, vascularisation, and acid profile of the cytoplasm. ; ; If the initial histologic analysis demonstrates that there are differences between samples exposed to active PBM compared to sham PBM, further analysis will be undertaken depending on what has been noted with histology. Further analyses by immunofluorescence +/‐ immunohistochemistry staining of samples may include extracellular matrix compounds, cell differentiation, and other target proteins. ; [Samples normally removed and discarded at the time of surgery (to accommodate the prosthetic implant) will be collected for analysis.] Forgotten Joint Score[Weeks 2, 4 and 6 after surgery ; At 6‐ and 12‐months after surgery] Hospital anxiety and depression scale (HADS)[Baseline one week prior to knee replacement surgery ; One day prior to knee replacement surgery ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] Joint range of motion (measured with goniometer)[Baseline one week prior to knee replacement surgery ; One day prior to knee replacement surgery ; Day 4 post‐operation ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] Knee circumference measured with tape measure (cm)[Baseline one week prior to knee replacement surgery ; Day 4 post‐operation ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] Knee Injury and Osteoarthritis Outcome Score (KOOS) [At baseline 1 week pre‐operatively ; At 6 and 12 months after surgery] Manual muscle strength test[Baseline one week prior to knee replacement surgery ; One day prior to knee replacement surgery ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] Side effects/Adverse events from study diary[One day prior to knee replacement surgery ; Day 4 post‐operation ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] Surgical wound healing [Assessed by blinded assessor from photographs taken at: ; Baseline 1 week before surgery ; Day 4 post‐operation ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation] Timed Up‐and‐Go test to assess functional mobility, balance and pain[Baseline one week prior to knee replacement surgery ; One day prior to knee replacement surgery ; Day 4 post‐operation ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] WOMAC knee score to assess pain, stiffness and physical function[Baseline one week prior to knee replacement surgery ; One day prior to knee replacement surgery ; 1 week post‐operation ; 2 weeks post‐operation ; 4 weeks post‐operation ; 6 weeks post‐operation ; 6 months post‐operation ; 12 months post‐operation] INCLUSION CRITERIA: Males and females between 60 and 87 years old and fit for surgery Undergoing unilateral total knee replacement surgery for severe osteoarthritis at the Mater Hospital Brisbane or Mater Private Hospital Brisbane