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Unicompartmental Knee System


Why simplicity is superior


There seems to be a growing consensus among orthopaedic surgeons that implants that retain the anterior cruciate ligament and preserve more of the articular geometry provide distinct advantages of superior proprioception, kinematics, and a more rapid recovery over tricompartmental knee replacement. Despite these benefits, isolated unicompartmental disease is rare. As with any surgery performed less frequently, the learning curve can be an issue, and literature has cited instances where more technically demanding UKA systems may have a higher failure rate. 1,2

Out of the need for a simplified procedure that retained versatility the JOURNEY UNI Unicompartmental Knee System was born. It represents a continuation of the legacy of Smith & Nephew's unicompartmental products, from the 1970s with the Marmor design to today with the clinically successful GENESIS resurfacing unicompartmental system. As a member of the JOURNEY Active Knee Solutions family, it also capitalizes on some of the design features first developed for the JOURNEY BCS Bi-Cruciate Stabilized Knee System. Ultimately, the needs and preferences of orthopaedic surgeons performing UKAs were the driving force behind the design and development of the JOURNEY UNI system. The key design goals are focused on:

1. Optimizing implant design through shape and size

2. Simplifying technique through streamlined instrumentation and familiar principles

3. Increasing longevity through use of an advanced bearing material


1. Lewold S, Goodman S, Knutson K, Robertsson O, Lidgren L. Oxford meniscal bearing knee versus the Marmor knee in unicompartmental arthroplasty for arthrosis. A Swedish multicenter survival study. J Arthroplasty. 1995 Dec;10(6):722-731.

2. Robertsson O, Knutson K, Lewold S, Lidgren L. The routine of surgical management reduces failure after unicompartmental knee arthroplasty. J Bone Joint Surg Br. 2001 Jan;83(1):45-49.


The JOURNEY UNI System: Simple

Surgical Technique

  • Streamlined gap balancing technique resembles that of contemporary TKA
  • Finishing block allows for sizing/positioning, finishing bone cuts and lug prep in one easy step
  •  Primary sizes have the same bone cuts and peg locations for seamless up- or downsizing even after resections have been made and pegs drilled


Femoral component

  • Anatomic implant treats both medial and lateral unicompartmental disease
  • Equal distal and posterior thicknesses for easier gap balancing
  • Forgiving femoral component placement – constant coronal radial geometry provides equivalent contact area at +/-12° off the coronal plane

Tibial component

  • Available in all-polyethylene and metal-backed baseplates
  • Fixation pegs are anteriorly placed for ease of implantation in less invasive procedures


The JOURNEY UNI System: Superior


Anatomic femoral fit

  • Optimized fit for each patient with seven handed sizes
  • 10° anterior angle closely matches patient anatomy
  • Bone conservation for smaller sizes with proportionate distal/posterior resection
  • Anatomic blend provides relief from patellar impingement


Anti-loosening feature

The angled cut and tapered, diverging lugs work together to resist femoral component loosening as the implant is pivoted onto the prepared condyle and cement is pressurized.

Bone preserving

  • Like the JOURNEY BCS Bi-Cruciate Stabilized Knee System, the JOURNEY UNI system has a 15° posterior flex cut to extend the articular surface in deep flexion while minimizing the bone resection
  • Tibial fixation pegs remove minimal bone and are less likely to fracture the tibia than keel designs
  • 7mm ‘thin’ option available in all polytheylene baseplate

Available in OXINIUM Oxidized Zirconium Technology

Exclusive to Smith & Nephew, OXINIUM technology combines the strength of metal with the wear resistance of ceramics.3,4

More normal kinematics

Because the JOURNEY UNI system retains both cruciate ligaments and makes minimal changes to the surface geometry of the knee, the kinematics will more closely resemble that of the normal knee.5,6,7,8


3. Hunter G, Long M. Abrasive wear of oxidized Zr-2.5Nb, CoCrMo, and Ti-6A1-4V against bone cement. Poster 528 presented at: 6th World Biomaterials Cong Trans, Society for Biomaterials, 1998.

4. Poggie RA, Wert JJ, Mishra AK, Davindson JA. Friction and wear characterization of UHMWPE in reciprocating sliding contact with CoCr, Ti-6Al-4V and zirconium implant bearing surfaces. In Denton R, Keshavan MK, eds. Wear and Friction of Elastomers. ASTM STP 1145 Philadelphia, PA: American Society for Testing and Materials; 1992:65–81.

5. Laurencin CT, Zelicof SB, Scott RD, Ewald FC. Unicompartmental versus total knee arthroplasty in the same patient. A comparative study. Clin Orthop Relat Res. 1991 Dec;(273):151–156.

6. Patil S, Colwell CW Jr, Ezzet KA, D’Lima DD. Can normal knee kinematics be restored with unicompartmental knee replacement? J Bone Joint Surg Am. 2005 Feb;87(2):332–338.

7. Carter ND, Jenkinson TR, Wilson D, Jones DW, Torode AS. Joint position sense and rehabilitation in the anterior cruciate ligament deficient knee. Br J Sports Med. 1997 Sep;31(3):209–212.

8. Rougraff BT, Heck DA, Gibson AE. A comparison of tricompartmental and unicompartmental arthroplasty for the treatment of gonarthrosis. Clin Orthop Relat Res. 1991 Dec;(273):157–164.

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Smith & Nephew is providing information in this site for general educational use only, and does not intend for this to be construed as medical advice or used as a substitute for the advice of your physician. For questions or concerns about a previous or upcoming surgery, Smith & Nephew recommends that you contact your healthcare professional.