- •
Unicompartmental knee arthroplasty (UKA) is an excellent surgical option for isolated medial or lateral unicompartmental osteoarthritis (OA). Initial studies were discouraging, but recent studies report greater than 85% survivorship at 10 years, with approximately 90% of patients reporting good to excellent subjective and objective outcomes.
- •
When comparing function and return to recreational activity, UKA is at least equivalent to high tibial osteotomy (HTO).
- •
Advantages of UKA versus total knee
Patient-Specific Instrumentation and Return to Activities After Unicondylar Knee Arthroplasty
Section snippets
Key points
Unicompartmental knee arthroplasty
This information is designed to help physicians and health care providers understand
- •
Indications and contraindications for UKA
- •
Expected outcomes for patients undergoing primary UKA and conversion to TKA
- •
Potential complications of UKA
- •
Discuss patient specific instrumentation and its impact on technique and preoperative planning
Indications
UKA is typically considered in younger and more active patients but also is considered in older sedentary patients with noninflammatory OA confined to a single tibiofemoral compartment (Fig. 1). To consider UKA, there should be minimal clinical patellofemoral or contralateral compartment symptoms. Knee range of motion (ROM) should include at least 100° of flexion and any fixed flexion contracture should be less than 10°. Historically, additional selection criteria included a maximum of 10° of
Surgical technique
The surgical goals of UKA are to replace damaged articular surfaces, restore limb alignment, and create a mechanical axis close to neutral to avoid overloading the contralateral compartment. Several different UKA guide systems can be used (intramedullary, extramedullary, spacer block, custom cutting blocks, and so forth) to ensure accurate osseous cuts and proper implant position. After surgical reconstruction, the joint line should be parallel to the floor and perpendicular to the mechanical
Outcomes
Outcomes from studies are summarized in Tables 2 and 3.10, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 These tables summarize articles with greater than 10-year follow-up (Table 3) as well as recent articles from post-2010 (see Table 3).2, 3, 4, 5, 6 The authors think that the recent articles highlight the newer implants available as well as many of the long-term studies that have recently been published. Because most current studies have shown survival rates of 85% to 90% at 10 to 15 years of
Complications
A complete list of potential complications is described in Box 1. As with TKR, UKA does also has the possibility of polyethylene wear and is more common with incongruity between the femoral component and the tibial insert. As longer follow-up studies have been performed, a distinction has been made between early and late failures (those occurring after 10 years), with late failures typically due to polyethylene wear. This was addressed by the development of the Oxford unicompartmental knee
Future areas of research
Future research on UKA will likely continue to expand on the indications of this procedure. Return to sports activity in increasingly active 50- to 60-year-old patients will likely necessitate further evaluation. Development of improved implant materials may be required as patients have increasing demands and a strong desire to return to preoperative function. Although the current generation of implants has shown good outcomes for 15 to 20 years with minimal wear, perhaps the next generation of
References (32)
- et al.
Yearly incidence of unicompartmental knee arthroplasty in the United States
J Arthroplasty
(2008) - et al.
Survivorship of UKA in the middle-aged
Knee
(2012) - et al.
Gait and clinical measurements in patients with knee osteoarthritis after surgery: a prospective 5-year follow-up study
Knee
(2005) - et al.
High tibial osteotomy versus unicompartmental joint replacement in unicompartmental knee joint osteoarthritis: 7-10-year follow-up prospective randomised study
Knee
(2001) - et al.
Unicompartmental knee arthroplasty surgery. 10-year minimum follow-up period
J Arthroplasty
(1996) - et al.
Radiological changes ten years after St George Sled unicompartmental knee replacement
Knee
(2004) - et al.
Medium-term results of Oxford phase-3 medial unicompartmental knee arthroplasty
J Orthop Surg (Hong Kong)
(2012) - et al.
Long-term survivorship and failure modes of unicompartmental knee arthroplasty
Clin Orthop Relat Res
(2013) - et al.
Minimum 10-year follow-up results of ALPINA cementless hydroxyapatite-coated anatomic unicompartmental knee arthroplasty
Eur J Orthop Surg Traumatol
(2013) - et al.
Minimally invasive oxford phase 3 Unicompartmental knee replacement: results of 1000 cases
J Bone Joint Surg Br
(2011)
High tibial osteotomy for medial osteoarthritis of the knee. A 5 to 7 and 11 year follow-up
J Bone Joint Surg Br
Unicompartmental arthroplasty and high tibial osteotomy for osteoarthrosis of the knee. A comparative study with a 12- to 17-year follow-up period
Clin Orthop Relat Res
Return to sports and recreational activity after unicompartmental knee arthroplasty
Am J Sports Med
Sports activities after medial unicompartmental knee arthroplasty Oxford III-what can we expect?
Int Orthop
A comparison of unicompartmental knee replacement with total knee replacement
Orthop Rev
Long-term clinical results of the medial Oxford unicompartmental knee arthroplasty
Clin Orthop Relat Res
Cited by (8)
Sports activity and patient-related outcomes after fixed-bearing lateral unicompartmental knee arthroplasty
2021, KneeCitation Excerpt :When conservative or joint-preserving methods fail, unicompartmental knee arthroplasty (UKA) has shown to be effective with good outcomes [5–10]. In particular, UKA has gained popularity especially among young and active patients [11–13]. These patients undergoing UKA often have high expectations concerning their postoperative level of activity [11,14–16].
Improved Survival of Computer-Assisted Unicompartmental Knee Arthroplasty: 252 Cases With a Minimum Follow-Up of 5 Years
2017, Journal of ArthroplastyCitation Excerpt :Despite these drawbacks, we still feel that the results of our study still show that good 5-year survival rates can be achieved by using CAS in UKA surgery. If improvement in survival of UKA can be further demonstrated in large multicenter studies, then using CAS, or any other technique (eg, patient-specific instrumentation, robot-assisted surgery) that consistently improves component alignment [34-37], could improve outcomes and cause revision rates to fall. This shift in balance alongside proven reduced early mortality and morbidity would challenge the contention of not performing UKA for eligible patients because of high failure rates [4].
Patient-specific instrument for unicompartmental knee arthroplasty does not reduce the outliers in alignment or improve postoperative function: a meta-analysis and systematic review
2020, Archives of Orthopaedic and Trauma SurgeryOutcomes and survivorship of unicondylar knee arthroplasty in patients with severe deformity
2017, Knee Surgery, Sports Traumatology, ArthroscopyExpectations of younger patients concerning activities after knee arthroplasty: are we asking the right questions?
2017, Quality of Life Research