J Knee Surg 2024; 37(02): 114-120
DOI: 10.1055/a-2186-6087
Special Focus Section

Anatomic Referencing Restores the Anatomy of the Distal Femur with Less Compromise

1   Department of Orthopaedic Surgery, Northwell Health Orthopaedics, Lenox Hill Hospital, New York, New York
Giles R. Scuderi
1   Department of Orthopaedic Surgery, Northwell Health Orthopaedics, Lenox Hill Hospital, New York, New York
› Author Affiliations


Historically, anterior referencing and posterior referencing are two specific techniques that surgeons can use for proper sizing of the femoral component in total knee arthroplasty (TKA). In this review, we introduce the concept of “anatomic referencing” which has become useful with more incremental sizes of the femoral component to more perfectly match the native anatomy of each patient and reduce overstuffing of the patellofemoral joint and medial-lateral (ML) overhang. Fifty consecutive TKA cases were reviewed where the novel anatomic referencing technique was used. Lateral radiographic projections were obtained preoperatively and postoperatively. The posterior condylar offset (PCO) was evaluated on the lateral radiographs by measuring the distance between the tangent line of the femoral diaphysis posterior cortex and the posterior condylar margin. PCO ratio (PCOR) was calculated by dividing the PCO by the distance between the posterior condylar border and a tangent line along the anterior cortex of the femoral diaphysis. Forty-five patients (50 TKAs) were reviewed. Average age of the patients was 70.34, range: 47–91. There were 19 males and 26 females reviewed in this series. On average, the delta PCOR was 0.022 (standard deviation = 0.032; min: –0.049, max: 0.082). When grouping our results into three main groups: < –0.03, –0.03 to 0.03, and > 0.03, we found that 62% fell within the –0.03 to 0.03 range. There was no statistically significant difference in delta PCOR between standard and narrow implants (p = 0.418). The proposed novel anatomic referencing technique has allowed for proper sizing of patients' femurs in the anteroposterior and ML direction while avoiding component overhang or the need for component downsizing to obtain a proper ML fit. This radiographic review confirmed this to be a highly accurate and reproducible technique.

Publication History

Received: 13 September 2023

Accepted: 04 October 2023

Accepted Manuscript online:
05 October 2023

Article published online:
16 November 2023

© 2023. Thieme. All rights reserved.

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  • References

  • 1 Scott CEH, Howie CR, MacDonald D, Biant LC. Predicting dissatisfaction following total knee replacement: a prospective study of 1217 patients. J Bone Joint Surg Br 2010; 92 (09) 1253-1258
  • 2 Bracey DN, Brown ML, Beard HR. et al. Effects of patellofemoral overstuffing on knee flexion and patellar kinematics following total knee arthroplasty: a cadaveric study. Int Orthop 2015; 39 (09) 1715-1722
  • 3 Nakajima A, Sonobe M, Akatsu Y. et al. Association between limb alignment and patient-reported outcomes after total knee arthroplasty using an implant that reproduces anatomical geometry. J Orthop Surg Res 2018; 13 (01) 320
  • 4 Peng Y, Arauz P, An S, Limmahakhun S, Klemt C, Kwon YM. Does component alignment affect patient reported outcomes following bicruciate retaining total knee arthroplasty? An in vivo three-dimensional analysis. J Knee Surg 2020; 33 (08) 798-803
  • 5 Charette RS, Sheth NP, Boettner F, Scuderi GR, Melnic CM. Femoral component sizing during total knee arthroplasty: anterior versus posterior referencing. JBJS Rev 2018; 6 (01) e4
  • 6 Johal P, Hassaballa MA, Eldridge JD, Porteous AJ. The posterior condylar offset ratio. Knee 2012; 19 (06) 843-845
  • 7 Chang MJ, Kang SB, Chang CB. et al. Posterior condylar offset changes and its effect on clinical outcomes after posterior-substituting, fixed-bearing total knee arthroplasty: anterior versus posterior referencing. Knee Surg Relat Res 2020; 32 (01) 10
  • 8 Lee O-S, Lee YS. Effect of the referencing system on the posterior condylar offset and anterior flange-bone contact in posterior cruciate-substituting total knee arthroplasty. J Arthroplasty 2018; 33 (04) 1069-1075
  • 9 Fokin AA, Heekin RD. Anterior referencing versus posterior referencing in total knee arthroplasty. J Knee Surg 2014; 27 (04) 303-308
  • 10 Han H, Oh S, Chang CB, Kang S-B. Changes in femoral posterior condylar offset and knee flexion after PCL-substituting total knee arthroplasty: comparison of anterior and posterior referencing systems. Knee Surg Sports Traumatol Arthrosc 2016; 24 (08) 2483-2488
  • 11 Vaidya SV, Ranawat CS, Aroojis A, Laud NS. Anthropometric measurements to design total knee prostheses for the Indian population. J Arthroplasty 2000; 15 (01) 79-85
  • 12 Yue B, Varadarajan KM, Ai S, Tang T, Rubash HE, Li G. Differences of knee anthropometry between Chinese and white men and women. J Arthroplasty 2011; 26 (01) 124-130
  • 13 Urabe K, Mahoney OM, Mabuchi K, Itoman M. Morphologic differences of the distal femur between Caucasian and Japanese women. J Orthop Surg (Hong Kong) 2008; 16 (03) 312-315
  • 14 Mahfouz MR, ElHak Abdel Fatah E, Bowers L, Scuderi G. A new method for calculating femoral anterior cortex point location and its effect on component sizing and placement. Clin Orthop Relat Res 2015; 473 (01) 126-132
  • 15 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
  • 16 Ha CW, Na SE. The correctness of fit of current total knee prostheses compared with intra-operative anthropometric measurements in Korean knees. J Bone Joint Surg Br 2012; 94 (05) 638-641
  • 17 Page SR, Pinzuti J-B, Deakin AH, Payne AP, Picard F. Profile of the distal femur anterior cortex–a computer-assisted cadaveric study. Orthop Traumatol Surg Res 2011; 97 (08) 821-825
  • 18 Malghem J, Maldague B. Depth insufficiency of the proximal trochlear groove on lateral radiographs of the knee: relation to patellar dislocation. Radiology 1989; 170 (02) 507-510
  • 19 Batailler C, Neyret P. Trochlear dysplasia: imaging and treatment options. EFORT Open Rev 2018; 3 (05) 240-247
  • 20 Poilvache PL, Insall JN, Scuderi GR, Font-Rodriguez DE. Rotational landmarks and sizing of the distal femur in total knee arthroplasty. Clin Orthop Relat Res 1996; (331) 35-46
  • 21 Dennis DA. Evaluation of painful total knee arthroplasty. J Arthroplasty 2004; 19 (4, Suppl 1): 35-40
  • 22 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
  • 23 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
  • 24 Dai Y, Scuderi GR, Bischoff JE, Bertin K, Tarabichi S, Rajgopal A. Anatomic tibial component design can increase tibial coverage and rotational alignment accuracy: a comparison of six contemporary designs. Knee Surg Sports Traumatol Arthrosc 2014; 22 (12) 2911-2923
  • 25 Clement ND, MacDonald DJ, Hamilton DF, Burnett R. Posterior condylar offset is an independent predictor of functional outcome after revision total knee arthroplasty. Bone Joint Res 2017; 6 (03) 172-178
  • 26 Onodera T, Majima T, Nishiike O, Kasahara Y, Takahashi D. Posterior femoral condylar offset after total knee replacement in the risk of knee flexion contracture. J Arthroplasty 2013; 28 (07) 1112-1116
  • 27 Malviya A, Lingard EA, Weir DJ, Deehan DJ. Predicting range of movement after knee replacement: the importance of posterior condylar offset and tibial slope. Knee Surg Sports Traumatol Arthrosc 2009; 17 (05) 491-498
  • 28 Massin P, Gournay A. Optimization of the posterior condylar offset, tibial slope, and condylar roll-back in total knee arthroplasty. J Arthroplasty 2006; 21 (06) 889-896
  • 29 Inacio MCS, Paxton EW, Graves SE, Namba RS, Nemes S. Projected increase in total knee arthroplasty in the United States - an alternative projection model. Osteoarthritis Cartilage 2017; 25 (11) 1797-1803