Risk Factors for Tibial Component Oversizing in Total Knee Arthroplasty among African Americans

Abstract

Incidences and risk factors for tibial component oversizing in total knee arthroplasty (TKA) have been well described, predominantly in Caucasian samples. Component oversizing has been linked to variations in proximal tibial shape and morphology, which has been found to be objectively different in African Americans compared with Caucasians. These anthropometric differences may affect the conformity of modern TKA systems to the anatomy of African Americans undergoing TKA. We sought to investigate the incidence and risk factors for tibial baseplate oversizing in an exclusively African American population undergoing TKA with a symmetric tibial baseplate. We reviewed the records of self-reported African American patients who had undergone a primary TKA at a single academic institution between 2005 and 2016. The primary outcome was incidence of tibial baseplate oversizing in the coronal and sagittal planes as determined by a single set of appropriately rotated postoperative orthogonal radiographs. Logistic regression models identified trends in oversizing within the population based on age, sex, body mass index (BMI), and TKA model. Among all 525 knees being evaluated, the occurrences of medial and lateral overhang were 14.2 and 15.2%, respectively. Increase in age was associated with lower risk of medial tibial overhang (odds ratio = 0.97 for each 1-year increase in age). Simple linear regression models described a linear relationship between BMI and overhang, with every one-unit increase in BMI, medial tibial overhang is 0.031 mm higher and posterior tibial overhang is 0.062 mm higher. Mediolateral oversizing was approximately twice more likely in females than males. Among TKA models used, the Stryker Triathlon had the least risk for mediolateral oversizing and the P.F.C. SIGMA demonstrated the least propensity for anteroposterior oversizing. To conclude, incidence of mediolateral tibial oversizing in this population was common. Previously identified variables affecting proximal tibial morphology, including age, body morphotype, and gender, may be equally applicable to the conformity of tibial baseplates in this population. Surgeons must pay particular attention to avoid mediolateral tibial oversizing in this population, especially in obese and older patients.

Keywords

total knee arthroplasty - prosthesis implantation - rotation

• References

• 1 Callahan CM, Drake BG, Heck DA, Dittus RS. Patient outcomes following tricompartmental total knee replacement. A meta-analysis. JAMA 1994; 271 (17) 1349-1357
• 2 Kim TK, Phillips M, Bhandari M, Watson J, Malhotra R. What differences in morphologic features of the knee exist among patients of various races? A systematic review. Clin Orthop Relat Res 2017; 475 (01) 170-182
• 3 Chau R, Gulati A, Pandit H. , et al. Tibial component overhang following unicompartmental knee replacement--does it matter?. Knee 2009; 16 (05) 310-313
• 4 Mandalia V, Eyres K, Schranz P, Toms AD. Evaluation of patients with a painful total knee replacement. J Bone Joint Surg Br 2008; 90 (03) 265-271
• 5 Bonnin MP, Schmidt A, Basiglini L, Bossard N, Dantony E. Mediolateral oversizing influences pain, function, and flexion after TKA. Knee Surg Sports Traumatol Arthrosc 2013; 21 (10) 2314-2324
• 6 McArthur J, Makrides P, Thangarajah T, Brooks S. Tibial component overhang in total knee replacement: incidence and functional outcomes. Acta Orthop Belg 2012; 78 (02) 199-202
• 7 Mahoney OM, Kinsey T. Overhang of the femoral component in total knee arthroplasty: risk factors and clinical consequences. J Bone Joint Surg Am 2010; 92 (05) 1115-1121
• 8 Bonnin MP, Saffarini M, Shepherd D, Bossard N, Dantony E. Oversizing the tibial component in TKAs: incidence, consequences and risk factors. Knee Surg Sports Traumatol Arthrosc 2016; 24 (08) 2532-2540
• 9 Clary C, Aram L, Deffenbaugh D, Heldreth M. Tibial base design and patient morphology affecting tibial coverage and rotational alignment after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2014; 22 (12) 3012-3018
• 10 Bellemans J, Carpentier K, Vandenneucker H, Vanlauwe J, Victor J. The John Insall Award: both morphotype and gender influence the shape of the knee in patients undergoing TKA. Clin Orthop Relat Res 2010; 468 (01) 29-36
• 11 Conley S, Rosenberg A, Crowninshield R. The female knee: anatomic variations. J Am Acad Orthop Surg 2007; 15: S31-S36
• 12 Hitt K, Shurman II JR, Greene K. , et al. Anthropometric measurements of the human knee: correlation to the sizing of current knee arthroplasty systems. J Bone Joint Surg Am 2003; 85-A (Suppl. 04) 115-122