Kinematic Versus Mechanical Alignment in Total Knee Replacement

Active, not recruiting

• Conditions: Total Knee Replacement

• Registration Number: NCT04384913
• Lead Sponsor: Hannover Medical School

Brief Summary

This prospective controlled double-blind randomized study compares kinematic and mechanical alignment in TKA (Total knee arthroplasty). A total of 120 patients will be included and the surgery will be performed using CT based 3D printed PSI(Patient Specific Instruments) Cutting guides.

Detailed Description

Total knee arthroplasty (TKA) is known, to significantly improve function and satisfaction in arthritic knee patients; nevertheless, a substantial percentage of these patients are not fully satisfied. Thus, several authors reported significantly improved outcomes after slightly under correcting varus knees after TKA. The concept of kinematic alignment (KA) even more addresses the patient´s individual anatomy with three-dimensional restoration of individual axes, joint lines and joint envelope of laxity. The aim of this prospective randomized study was to demonstrate equivalence between mechanical and kinematic alignment in restoring knee function in terms of subjective and objective outcomes.

In this prospective randomized controlled double-blind study 120 patients with osteoarthritic knees will be treated with a Medial Pivot TKA (Medacta Sphere GMK). The patients are divided into two groups. Group A receive the TKA using mechanical alignment principles, group B receive the kinematic alignment. The surgical technique was equal in both groups. CT-based 3D printed PSI cutting blocks were used for the saw cuts. Pre and postoperative standard x-rays were performed. To determine the subjective and objective outcomes the OKS(Oxford Knee Score), the KSS(Knee Society Sore), the FJS-12(Forgotten Joint Score) and the WOMAC Score were collected.

Study Timeline

• Study Start: 2017-08-01
• Study First Submitted: 2020-04-28
• Study First Submitted QC: 2020-05-11
• Study First Posted: 2020-05-12
• Primary Completion: 2022-09-23
• Status Verified: 2025-03
• Last Update Submitted: 2025-03-21
• Last Update Posted: 2025-03-25
• Study Completion: 2026-01-30

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 130

Inclusion Criteria

• Symptomatic osteoarthritis of the knee
• Primary TKA
• UCLA Score (University of California, Los Angeles Score)>/= 4
• mMPTA: 85°- 90°
• Sum of mMPTA(mechanical medial proximal tibial angle) and mLDFA(mechanical lateral distal femoral angle) between 3°varus and 2°valgus from neutral

Exclusion Criteria

• Minor Patient
• Pregnant or breast feeding woman
• Difference in the radius of medial and lateral condyles >2mm
• Previous osteotomy around the knee
• BMI >40
• Ligament instability likely to require higher level of constraint
• Previous infection or inflammatory disease
• Any Patient who cannot or will not provide informed consent for participation in the study

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Knee Society Score (KSS)	24 months postoperative	The Knee Society Scoring System is a validated and responsive method for assessing objective and subjective outcomes after total and partial knee arthroplasty.; Minimum: 0 (worst), Maximum: 100 (best)

Secondary Outcome Measures

Name	Time	Method
Forgotten Joint Score (FJS-12)	24 months postoperative	The FJS Knee was designed to assess patient outcome in patients undergoing conservative or operative treatment of the knee. This questionnaire shows its strengths in patients with a good level of knee function and a low pain level. It has been designed specifically to reduce ceiling effects commonly associated with many PRO measures in this patient group, e.g. when assessing short- to mid-term results in total knee arthroplasty patients.; Minimum: 0 (worst), Maximum: 100 (best)
Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)	24 months postoperative	The WOMAC Score was developed in 1982 and is a Patient Reported Outcome (PRO) instrument to assess the effects of osteoarthritis of the hip and/or knee joint in affected patients. The WOMAC-Score contains 24 questions and is able to assess the effects of osteoarthritis of the hip and/or knee joint with regard to three subscales: Pain - 5 questions Stiffness - 2 questions Physical function - 17 questions Minimum: 0 (best), Maximum: 100 (worst)
Oxford Knee Score (OKS)	24 months postoperative	The OKS questionnaire consists of 12 questions that cover function and pain of the knee. Each question is scored from 0 to 4 (0 being the worst outcome and 4 being the best). The overall score is the sum of all items and can range from 0 to 48, with higher scores corresponding to better outcomes. The OKS has a big ceiling effect and cannot differentiate between good and very good results. However, the most of the researchers world wide use the OKS as a reference.

Trial Locations

Locations (1)

Orthopädische Klinik der Medizinischen Hochschule Hannover im DIAKOVERE Annastift; 🇩🇪 Hanover, Niedersachsen, Germany