International Orthopaedics

, Volume 39, Issue 8, pp 1519–1526 | Cite as

Patient-specific implants for lateral unicompartmental knee arthroplasty

  • Marco K. DemangeEmail author
  • Arvind Von Keudell
  • Christian Probst
  • Hiroshi Yoshioka
  • Andreas H. Gomoll
Original Paper



The lateral compartment of the knee is biomechanically and anatomically different from the medial compartment. Most commercially available unicompartmental implants are not designed specifically for the lateral compartment. Patient-specific custom-made unicompartmental knee arthroplasty (UKA) are designed to provide optimal fit on both femoral and tibial surfaces. This study aimed to determine if the use of patient-specific lateral unicompartmental implants provide better bone coverage than standard, off-the-shelf commercially available unicompartmental implants in lateral unicompartmental knee arthroplasties. As a secondary question, we wished to determine if patient-specific unicompartmental implants provide good clinical outcomes in surgical treatment of lateral unicompartmental osteoarthritis.


We prospectively evaluated 33 patients who underwent lateral unicompartmental arthroplasty using patient-specific implants and instrumentation with a minimum of 24 months of follow-up. We analysed bone coverage observed in plain radiographs in 33 patient-specific lateral unicompartmental arthroplasties and compared to 20 lateral unicompartmental arthroplasties performed with commercially-available, standard off-the-shelf unicondylar implants.


The mean tibial implant lateral coverage mismatch in the patient-specific implant group was 1.0 mm (S.D. 1.2, range 0–5.7 mm ) versus 3.3 mm (S.D. 2.43, range 0.4–7.8 mm) in the conventional implant group (p < 0.01). In the patient specific cohort, pre-operative limb alignment was 3.3 (valgus) and post-operative limb alignment was −0.9 (varus). The Knee Society score improved from 48 (S.D. 16.2) to 95 (S.D. 7.6). Survivorship in the patient-specific implant group was 97% at an average follow up of 37 months, versus 85% at a follow-up period of 32 months for the standard implant group.


Patient-specific lateral unicompartmental knee replacements demonstrated better tibial coverage and provide excellent short-term clinical and radiological results as compared to a standard lateral UKA.


Knee Osteoarthritis Unicompartmental arthroplasty Patient-specific implants Tibia Lateral Custom-made 



No funding was received for the research project.


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Copyright information

© SICOT aisbl 2015

Authors and Affiliations

  • Marco K. Demange
    • 1
    • 3
    Email author
  • Arvind Von Keudell
    • 1
  • Christian Probst
    • 1
  • Hiroshi Yoshioka
    • 2
  • Andreas H. Gomoll
    • 1
  1. 1.Brigham and Women’s HospitalHarvard Medical SchoolBostonUSA
  2. 2.University of CaliforniaIrvineUSA
  3. 3.Faculty of MedicineUniversity of São PauloSão PauloBrazil

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