title: How Much Does the Anatomical Tibial Component Improve the Bony Coverage in Total Knee Arthroplasty?
abstract: Recently, anatomical designs in total knee arthroplasty are introduced to address asymmetry of the resected tibia cutting surface. It is still not well known how much improvement would be achieved in total knee arthroplasty, especially in Asian knees.
  
  
  
  We evaluated the bony coverage of 4 commercially available posterior-stabilized tibial designs (3 symmetrical: NexGen, Attune, and Vega; 1 anatomical: Persona) by measuring uncovered areas over 3 different regions: lateroposterior (LP), medioposterior (MP), and mediolateral (ML) areas. The implant size was chosen based on lateral anteroposterior dimension of the implant that most closely matched the corresponding surface of tibia. The knee with over coverage <1 mm and under coverage <2 mm was regarded as having optimal fit.
  
  
  
  The optimal fit of anatomical design in LP dimension was achieved in 76% of the cases, which was not significantly different from other symmetrical designs (P > .05). The anatomical tibial implant had a more optimal fit in MP and ML dimensions (48% and 42%, respectively) compared to all symmetric designs (P < .05). All symmetrical tibial designs had significant absolute underhang in MP (62%-78%) and ML (24%-34%) areas without difference. The anatomical tibial design had significant improvement for posteromedial coverage by about 69.8%-74.3% compared with the symmetrical designs.
  
  
  
  Recently introduced anatomical tibial design improves surface coverage at the medioposterior dimension in Asian knees. Moreover, there is small improvement in ML fit compared with the symmetrical designs.
authors.affiliation: Center for Joint Disease, Department of Orthopaedic Surgery, Chonnam National University Hwasun Hospital, Hwasun, Korea; Department of Orthopedic Surgery, Chinese People's Armed Police Force, Zhejiang Corps Hospital, Jiaxing, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Jin
authors.affiliation: Center for Joint Disease, Department of Orthopaedic Surgery, Chonnam National University Hwasun Hospital, Hwasun, Korea.
authors.forename: Eun-Kyoo
authors.initials: EK
authors.lastname: Song
authors.affiliation: Center for Joint Disease, Department of Orthopaedic Surgery, Chonnam National University Hwasun Hospital, Hwasun, Korea.
authors.forename: Jatin
authors.initials: J
authors.lastname: Prakash
authors.affiliation: Center for Joint Disease, Department of Orthopaedic Surgery, Chonnam National University Hwasun Hospital, Hwasun, Korea.
authors.forename: Sung-Kyu
authors.initials: SK
authors.lastname: Kim
authors.affiliation: Center for Joint Disease, Department of Orthopaedic Surgery, Chonnam National University Hwasun Hospital, Hwasun, Korea.
authors.forename: Chee Ken
authors.initials: CK
authors.lastname: Chan
authors.affiliation: Center for Joint Disease, Department of Orthopaedic Surgery, Chonnam National University Hwasun Hospital, Hwasun, Korea.
authors.forename: Jong-Keun
authors.initials: JK
authors.lastname: Seon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D044466:Asian People; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D013977:Tibia / Q000601:surgery*
keywords: anatomical; symmetrical; tibial coverage; tibial design; total knee arthroplasty