A novel technique for estimating component sizes in total knee arthroplasty.

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Radiology

Background:

• Intra-operative assessment of total knee arthroplasty (TKA) components typically relies on manufacturer-specific jigs.
• While pre-operative templating, patient-specific cutting blocks, and computer-assisted surgery aim to improve TKA alignment and sizing, literature indicates only marginal improvements in functional outcomes.
• A simple, accessible method for estimating TKA component sizes pre-operatively is needed.

Purpose of the Study:

• To investigate the relationship between pre-operative shoe size and total knee arthroplasty (TKA) component sizes.
• To explore the correlation between TKA implant sizes, patient height, body weight, and shoe size.
• To determine if shoe size can serve as a simple tool for estimating TKA prosthesis size.

Main Methods:

• A retrospective single-center cohort study was conducted.
• Data from 106 patients undergoing primary knee arthroplasty between August and November 2015 were analyzed.
• Spearman's rank correlation was used to assess relationships between shoe size, height, weight, and TKA component sizes (femoral and tibial).

Main Results:

• Statistically significant positive correlations were found between shoe size and both femoral (rho=0.589, p<0.05) and tibial (rho=0.718, p<0.05) component sizes.
• Significant correlations were also observed between shoe size and height (rho=0.692, p<0.05).
• Height showed significant correlations with femoral (rho=0.626, p<0.05) and tibial (rho=0.674, p<0.05) component sizes.

Conclusions:

• A positive correlation exists between shoe size and total knee arthroplasty component sizes.
• Pre-operative shoe size can be utilized as a simple estimation tool for determining appropriate TKA prosthesis size.
• This finding may aid surgeons in pre-operative planning for total knee replacement surgery.