Patient - implant dimension mismatch in total knee arthroplasty: Is it worth worrying? An Indian scenario

• Published in: Indian journal of orthopaedics Vol. 50; no. 5; pp. 512 - 517
• Main Authors: Thilak, Jai, George, Melvin J.
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.09.2016; Wolters Kluwer - Medknow Publications; Medknow Publications and Media Pvt. Ltd; Medknow Publications & Media Pvt. Ltd; Medknow Publications & Media Pvt Ltd
• Subjects: Conservative Orthopedics; Knee replacement arthroplasty; Medicine & Public Health; Original; Original Article; Orthopedics; Prostheses and implants; Surgical Orthopedics; mediolateral mismatch; total knee arthroplasty; knee; Distal femoral dimensions; arthroplasty; osteoarthritis; femoral component; Orthopaedic equipment; replacement; gender specific knee; total knee arthroplasty MeSH terms: Orthopaedic equipment
• ISSN: 0019-5413; 1998-3727
• DOI: 10.4103/0019-5413.189618

Background: The correct sizing of the components in both anteroposterior and mediolateral (ML) dimensions is crucial for the success of a total knee arthroplasty (TKA). The size of the implants selected is based on the intraoperative measurements. The currently used TKA implants available to us are based on morphometric measurements obtained from a Western/Caucasian population. Hence, the risk of component ML mismatch is more common in Asian sub-population, as they are of a smaller built and stature. This study aims to look into the following aspects - magnitude of the ML mismatch between the femoral component and the patient’s anatomical dimension, evaluation of gender variations in distal femur dimensions, and gender-wise and implant-wise correlation of ML mismatch. Materials and Methods: Intraoperatively, the distal femoral dimensions were measured using sterile calipers after removing the osteophytes and compared with the ML dimension of the implant used. ML mismatch length thus obtained is correlated with the various parameters. Results: Males showed larger distal femoral dimensions when compared to females. Males had larger ML mismatch. None of the implants used perfectly matched the patient’s anatomical dimensions. Patients with larger mismatch had lower scorings at 2 years postoperative followup. Conclusion: Implant manufacturers need to design more options of femoral implants for a better fit in our subset of patients. The exact magnitude of mismatch which can cause functional implications need to be made out. The mismatch being one of the important factors for the success of the surgery, we should focus more on this aspect.