This is a single centre, randomised, patient blinded pilot study that will assign 40 participants with medial knee osteoarthritis undergoing medial opening wedge high tibial osteotomy (MOWHTO) to either current standard of care with TOMOFIX plating system, or utilise patient specific instrumentation and custom-made plate development, with BodyCAD Fine Osteotomy. If the definitive study is deemed feasible, an additional 110 participants will be randomized, for a total of 150 participants.
The proposed study is a single centre, pilot randomised controlled, patient blinded study that will randomly assign 40 participants with medial knee osteoarthritis undergoing medial opening wedge proximal tibial osteotomy (MOWHTO) to either current standard of care, with TOMOFIX plating system, or utilise patient specific instrumentation and custom-made plate development, with BodyCAD Fine Osteotomy. Participants will follow a standardized rehabilitation protocol. Outcomes will be assessed over two years postoperatively utilising CT assessment for accuracy of correction, bony union and construct stability as well as PROMs including KOOS and EQ5D. Complications, adverse events, returns to theatre and costs will also be recorded. End of study is defined when the last enrolled subject reaches the 24-month follow-up time point and close-out activities are complete. If the pilot study demonstrates the feasibility of the definitive trial, an additional 110 participants will be ennrolled, for a total of 150 participants.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
40
TOMOFIX: A guidepin is placed to determine the level and length of the osteotomy with an appropriate hinge position selected. The oscillating saw is then used along with osteotomes to complete the osteotomy under image intensifier guidance. This is opened to the desired width of correction with a trapezoidal gap noted when using laminar spreader in the posterior position to avoid slope change. The plate is then applied and secured as per manufacturers operative technique.
BodyCAD: The patient specific cutting block is applied to the proximal tibia and secured in placed. The osteotomy is then created with sequential drills and osteotome and opened to the predetermined correction as per the manufacturer's guidelines. The plate is applied and secured with the supplied screws.
KOOS
The KOOS is a 42-item knee-specific questionnaire with five separately reported domains, including pain, other symptoms, function in daily living, function in sports/recreation and knee-related quality of life. Domain scores represent the average of all items in the domain standardized to a score from 0 to 100 (worst to best). This instrument has demonstrated construct validity, excellent test-retest reliability for each domain (range, 0.75 to 0.93) and is responsive to change.
Time frame: Baseline, 6 weeks, 3 months, 6 months, 12 months, 24 months
EQ-5D (Index and VAS)
The EuroQoL comprises two sections, the EQ-5D index and the EQ-5D visual analogue scale (VAS). The EQ-5D index is a 5-item standardized generic measure of HRQOL that includes domains of mobility, self-care, usual activities, pain and discomfort and anxiety and depression. Each item is scored using a 5-point response scale and each combination of response choices describes a health state (3125 unique health states). Each health state can be converted to a utility value from 0 (worst) to 1.0 (best) using a scoring formula. The EQ-5D VAS is a 0 (worst) to 100 (best) scale that assesses patient-perceived health status responsiveness among patients undergoing knee arthroscopy.
Time frame: Baseline, 6 weeks, 3 months, 6 months, 12 months, 24 months
Procedure Time
To determine the length of the surgery, the timing will be extracted from the intra-operative nursing record, the time of first incision and the time of closing and calculate the amount of time in minutes. To determine the amount of fluoroscopic time, the time will be extracted from image intensifier record the amount of fluoroscopic imaging utilised in the operating room and calculate a total exposure time in seconds.
Time frame: Surgery
Adverse Events
All adverse events will be recorded and the relatedness, severity and expectedness to the study protocol will be classified. Plain radiographs will be used at each follow-up to assess for the presence of a hinge fracture and delayed or non-union. Loss of motion/arthrofibrosis will be assessed by a blinded assessor who will measure passive and active knee extension and active-assisted knee flexion with a goniometer. For passive knee extension, the patient will lie supine on the examination table with a bolster under the heels with the quadriceps and hamstrings relaxed to assure full passive extension of the knee. For active-assisted knee flexion, the patient will be seated on the examination table with both legs extended and instructed to perform active-assisted knee flexion by placing one hand under their thigh to initiate flexion and then clasp both hands just below the tibial tuberosity. The side-to-side difference in ROM will be determined and interpreted based on IKDC guidelines.
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Time frame: Baseline, 6 weeks, 3 months, 6 months, 12 months, 24 months
Cost Effectiveness
Participants who suffer an adverse event will be asked to complete a healthcare resource use diary to capture additional direct and indirect healthcare resources from the time of surgery to the end of the study period. This will include any emergency room visits, hospitalizations, family doctor visits, additional outpatient clinic visits, tests, procedures, prescription or over-the-counter medications and any miscellaneous costs related to their knee. Employment status and time-off paid employment, homemaking or volunteer activities, for both participants and their caregivers, if applicable will be recorded. Quality-adjusted life years (QALYs) using the European Quality of Life Scale (Euro-QoL) will be measured.
Time frame: Baseline, 6 weeks, 3 months, 6 months, 12 months, 24 months