Comparison of Functional Recovery Between Restricted Inverse Kinematic Alignment and Adjusted Mechanical Alignment with Robotic-assisted Unilateral Total Knee Arthroplasty.

Not Applicable

Not yet recruiting

• Conditions: OA Knee; TKA

• Registration Number: NCT06835621
• Lead Sponsor: Thammasat University

Brief Summary

The goal of this clinical trial is to learn if restricted inverse kinematic alignment total knee arthroplasty (restricted iKA TKA) improves functional recovery compared to adjusted mechanical alignment total knee arthroplasty (aMA TKA) in patients undergoing unilateral robotic-assisted total knee arthroplasty by comparing performance-based outcome, 2-minute walk test (2MWT) as a primary outcome. This trial will also assess other outcomes including satisfaction, patient-reported functional outcomes, range of motion, visual analog scale for pain and complication of both techniques. The main question aims to answer is:

In unilateral robotic-assisted total knee arthroplasty, dose Restricted iKA technique provide better postoperative performance-based outcome compared to aMA technique?

Researchers will compare restricted iKA and aMA technique to determine which technique offers better acceleration in functional recovery and patient satisfaction.

Participants will:

After randomization, participants will allocate to either restricted iKA or aMA technique for unilateral robotic-assisted total knee arthroplasty.

Attend follow-up visits for assessments of 2-minute walk test (Primary outcome), Time up and go test (TUG), VAS for pain, ROM and complete patient-reported functional outcome questionnaires regarding knee function and satisfaction at regular intervals.

Detailed Description

Nowadays, total knee arthroplasty (TKA) for the treatment of osteoarthritis patients generally aims to achieve a neutral alignment of the leg. This involves cutting the bones perpendicular to the mechanical axis in both the femur and tibia. This method is called mechanical alignment TKA (MA TKA), which is widely popular and is often considered the standard technique for TKA. It has shown satisfactory long-term outcomes. However, despite advancements in materials and surgical techniques, MA TKA still requires bone and soft tissue adjustments to correct alignment, which may involve releasing soft tissues. This can result in post-surgical pain or dissatisfaction, with up to 20% of patients reporting dissatisfaction despite improved knee pain compared to pre-surgery. Furthermore, 1 in 4 of these dissatisfied patients do not wish to undergo a revision surgery, as the MA TKA method is a "one-size-fits-all" approach that aims to achieve equal and parallel gaps between the femur and tibia components without respecting individual soft tissue balance and the original alignment of each patient's leg. However, adjusted mechanical alignment technique, an adaptation of conventional MA technique with under-correction of constitutional coronal deformity, within a limit of ± 3° (HKA -3° to 3) has been introduced according to the constitutional deformity and coronal plan alignment of the knee concept.

In 2006, Howell introduced kinematic alignment TKA (KA TKA) as an alternative, with the goal of restoring the patient's natural kinematic axis and reducing the incidence of pain related to TKA rather than focusing on equal medial and lateral joint line gap and neutral mechanical axis like in mechanical alignment technique. KA TKA is considered a more personalized approach because it aims to replicate the knee's pre-arthritic alignment and movement, believing that each patient's knee has a unique alignment. This approach has gained increasing interest in recent years, with studies reporting good short- to mid-term clinical outcomes. However, the KA technique is more complex because we cannot always know the pre-arthritic alignment of individual patients and measuring soft tissue tension remains imprecise.

Later, Dr. Pascal-André Vendittoli proposed the restricted kinematic alignment TKA (rKA TKA) technique to restore natural knee movement while avoiding excessive correction of coronal alignment by maintain the HKA axis within ± 3 degrees (safe zone). By maintaining some of the constitutional deformity, this technique reduces the need for excessive soft tissue or ligament releases. In 2020 Winnock et al, introduced the Inversed kinematic technique (iKA) or tibia-referenced technique by resurfacing the tibia with equal medial and lateral resections maintaining the native tibial joint line obliquity before distal femoral bone. When combines these KA principles with robotic-assisted TKA, enhancing the accuracy of soft tissue balancing and the overall effectiveness of the procedure.

In 2020, McEwen et al. compared the use of robotic-assisted KA with MA in the same patients who underwent bilateral knee surgery using different techniques. They found that clinical outcomes, including range of motion and knee scores, were not significantly different at any time point. However, Elbuluk conducted a similar comparison, specifically robotic-assisted (MAKO) KA versus MA, and found that the KA group had less pain and better knee scores, including a higher Forgotten Joint Score. Later, Abhari conducted a study comparing robotic-assisted (MAKO) restricted KA with non-robotic MA TKA and found that the robotic-assisted (MAKO) restricted KA group had superior clinical outcomes and knee scores, including the Forgotten Joint Score, KOOS, WOMAC, Knee Society Score, as well as greater patient satisfaction. However, there are still limited prospective RCTs that study differences in outcomes, especially performance-based outcomes between restricted inverse kinematic alignment (restricted iKA) versus adjusted mechanical alignment (aMA). Therefore, the researchers aim to conduct a study comparing the efficiency of performance-based outcomes as a primary focus, including patient-reported outcome questionnaires, ROM, VAS for postoperative pain, postoperative morphine consumption within 24 hours, postoperative lower limb alignment (HKA axis), operative time, blood loss, and complications. The goal is to further advance the development of knee replacement surgery.

Study Timeline

• Status Verified: 2025-02
• Study First Submitted: 2025-02-14
• Study First Submitted QC: 2025-02-14
• Last Update Submitted: 2025-02-14
• Study First Posted: 2025-02-19
• Last Update Posted: 2025-02-19
• Study Start: 2025-03
• Primary Completion: 2026-08
• Study Completion: 2028-08

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 80

Inclusion Criteria

• Age 50 - 80 years old
• Diagnosed with primary OA knee and indicated for unilateral total knee arthroplasty with MAKO robotic-assisted knee replacement system
• ASA classification I-II

Exclusion Criteria

• Valgus deformity
• KL grading > 3 on contralateral knee
• Unable or difficulty for walking due to comorbidities
• BMI > 40 kg/m2
• Previous knee surgery
• Infection around the knee

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
2-minute walk test	From enrollment (preoperative measurement) to the end of postoperative follow-up (2 years)	The 2-minute walk test (2mwt) is a performance-based test that evaluates functional recovery after total knee arthroplasty (TKA) by measures the distance a person can walk in two minutes (meters) and has been validated as performance-based test with responsiveness properties. Being simple and easy to perform, it can be used routinely in clinical practice to evaluate functional recovery after TKA.

Secondary Outcome Measures

Name	Time	Method
Time up and go test	From enrollment (preoperative measurement) to the end of postoperative follow-up (2 years)	The Timed Up and Go test (TUG) are simple, quick, and can be applied in a short time as part of the routine medical examination. They were shown to be reliable and valid tests in many patient groups including postoperative performance-based outcome for patients undergone TKA.
modified WOMAC scale for knee pain (Thai version)	From enrollment (preoperative measurement) to the end of postoperative follow-up (2 years)	The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) is a widely used questionnaire for assessing pain, stiffness, and functional limitation in patients with osteoarthritis, particularly in the knee and hip joints. The modified WOMAC scale adapts the original WOMAC to better suit specific populations or clinical settings. In this study, we use the modified WOMAC scale for knee pain Thai version to assess the pre and post operative functional outcome.
Thai version of the Forgotten Joint Score	From enrollment (preoperative measurement) to the end of postoperative follow-up (2 years)	This score aims for evaluation of joint awareness in everyday life, which is one of the aspects to evaluate the outcome and the ability to forget the artificial joint, is claimed as the ultimate goal resulting in maximum patient satisfaction. The Thai language version of the FJS had high level of internal consistency and was proved to be a reliable tool for evaluating knee arthroplasty patients in Thailand. The low ceiling effect characteristic of the score can help the surgeon to detect small difference in the good and excellent outcomes after knee arthroplasty.
Oxford knee score	From enrollment (preoperative measurement) to the end of postoperative follow-up (2 years)	The Oxford Knee Score (OKS) is a widely used patient-reported outcome measure designed to assess the function and quality of life of individuals with knee problems, particularly those undergoing knee surgery, such as total knee arthroplasty. It focuses specifically on how knee-related issues affect daily activities and overall well-being. (Thai version is available on the official website of the Oxford knee score website)
Range of Motion	From enrollment (preoperative measurement) to the end of postoperative follow-up (2 years)	Preoperative and Postoperative active range of motion (ROM) will be recorded for evaluation of the knee ROM for both groups including flexion contracture (FC) or extension gap which may be presented as complication.
Hip knee ankle angle	From enrollment (preoperative measurement) and at 1-year postoperative follow-up.	The hip knee ankle angle is radiographic measurement for determine the coronal alignment of the lower limbs. On a weight-bearing, full-length AP lower limb radiograph measuring 2 lines from center of the femoral head to the femoral intercondylar notch, while the latter from the tibial interspinous point to the tibial mid-plafond. The HKA is defined as the angle between these two lines.
Visual analog scale for Pain	From enrollment (preoperative measurement) to the end of postoperative follow-up (2 years)	Each patient will be asked for Visual analog scale (VAS) for pain for the knee, which is the subjective patient reported pain rating from 0-10 either from numerical order or facial expression picture indicating 0 is the minimum or no pain and 10 is the maximum or the worst pain.
Morphine consumption	Postoperative interval of 24-72 hours	Postoperative morphine consumption (mg) in the first 72 hours during hospital admission could reflect the need of strong opioid as the rescue analgesia after operation.
Complication	After surgery and up to 2 years	Total knee arthroplasty-related complication e.g. surgical site infection, bleeding, wound complication, deep vein thrombosis, acute pulmonary embolism and implant failure.
Medial proximal tibial angle (MPTA)	From enrollment (preoperative measurement) and at 1-year postoperative follow-up.	In whole leg AP weight baring film, measure the proximal medial angle formed between the tibial mechanical axis and the knee joint line of the tibia in the frontal plane.
Lateral distal femoral angle (LDFA)	From enrollment (preoperative measurement) and at 1-year postoperative follow-up.	In whole leg AP weight baring film, it's defined as the lateral angle formed between the mechanical axis line of the femur and the knee joint line of the femur.
Joint line obliquity (JLO)	From enrollment (preoperative measurement) and at 1-year postoperative follow-up.	Joint line obliquity (degrees) = MPTA + LDFA

Trial Locations

Locations (1)

Faculty of Medicine, Thammasat University; 🇹🇭 Klongluang, Pathum-Thani, Thailand