Sexual dimorphism and racial diversity render bone–implant mismatch inevitable after off-the-shelf total knee arthroplasty: a systematic review and meta-analysis

Abstract

Purpose The purpose of this systematic review and meta-analysis was to investigate the variability in femoral geometric ratios among knees of diferent sexes and races, and to appreciate whether the observed variability is accommodated by commonly implanted total knee arthroplasty (TKA) components. The hypothesis was that the anthropometric studies report considerable variability of femoral geometric ratios among sexes and races. Methods This systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) criteria. Two authors independently conducted an electronic search using MEDLINE ® and Embase ® on 6 July 2020 for clinical studies reporting on femoral geometric ratios among sexes and races. Femoral geometric ratios were graphically represented as means and 2 standard deviations, and compared to those of 13 commonly implanted femoral components. Results A total of 15 studies were identiied that reported on a combined total of 2627 knees; all reported the aspect ratio, and 2 also reported the asymmetry ratio and trapezoidicity ratio. Men had wider knees than women, and compared to Caucasian knees, Arabian and Indian knees were wider, while East Asian were narrower. There were no diferences in asymmetry ratio between men and women, nor among Caucasian and East Asian knees. Men had more trapezoidal knees than women, and East Asian knees were more trapezoidal than Caucasian knees. The commonly implanted femoral components accommodated less than a quarter of the geometric variability observed among sexes and races. Conclusion Anthropometric studies reported considerable sexual dimorphism and racial diversity of femoral geometric ratios. Since a surgeon generally only uses one or a few TKA brands, bone-implant mismatch remains unavoidable in a large proportion of knees. These indings support the drive towards personalized medicine, and accurate bone-implant it may only be achievable through customisation of implants, though the clinical beneits of custom TKA remain to be conirmed. Level of evidence IV.

Análise matemática da área descoberta pelo componente femoral em prótese total de joelho com undersizing

“…Próteses menores não levam a cobertura óssea total com aumento da hemorragia e perda de área de fixação, principalmente cortical. No entanto, os benefícios dos implantes personalizados ainda não foram confirmados [9]. InterAm J Med Health 2022;5:20220224 Neste estudo, calculamos a área de osso exposto em componente femoral subdimensionado.…”

Biomechanical Effects of Aspect Ratio of the Knee during Outside-In Anterior Cruciate Ligament Reconstruction Surgery

“…According to Beckers et al [ 36 ], men had wider knees (range 108~151%) than women (range 106~146%), and compared to Caucasian knees (range 116~126%), Arabian (range 106~149%) and Indian (range 118~147) knees were wider, while East Asian knees were narrower (range 100~118). This study on Korean men showed knee ASRs of 95~119%, similar to the results of a previous study on Asians [ 37 , 38 ].…”

Custom total knee arthroplasty combined with personalised alignment grants 94% patient satisfaction at minimum follow-up of 2 years

“…Off-the-shelf (OTS) TKA can result in implant overhang, malalignment and/ or abnormal kinematics [45]. This can be attributed to the inability of OTS TKA to cover the considerable morphologic variability observed in anthropometric studies [3,4,13]. Custom TKA based on computed tomography (CT) reconstructions has the potential to re-establish native tibial and femoral shapes, and reduce bone-implant mismatch, while restoring constitutional alignment (CA) within predetermined limits to maintain overall phenotype [18][19][20].…”