Minimum 10-Year Survivorship of Mobile-Bearing Unicompartmental Arthroplasty: Single Surgeon, North American Non-Designer Consecutive Series

doi:10.1016/j.arth.2022.02.066

The Journal of Arthroplasty

Volume 37, Issue 6, Supplement, June 2022, Pages S88-S93

https://doi.org/10.1016/j.arth.2022.02.066 Get rights and content

Abstract

Background

Mobile-bearing unicompartmental knee arthroplasty (UKA) provides a durable option for the surgical treatment of monocompartmental knee arthritis. Despite its availability in the United States since 2004, there is only 1 published North American series reporting on the minimum 10-year results of mobile-bearing UKA. The purpose of this study is to determine the survivorship, reasons for failure, and patient-reported outcomes of the Oxford mobile-bearing UKA at minimum 10-year follow-up.

Methods

One hundred fifty-seven knees were eligible for inclusion in this study based on the date of their index surgery allowing for a minimum 10-year follow-up. The mean follow-up from implantation was 11.4 years (range 10.0-13.8). Failures were reviewed for potential etiologic factors. Survivorship free of reoperation for any reason and free of revision was determined using Kaplan-Meier curves. Functional outcomes were assessed using the Knee Society Knee and Function scores.

Results

There were 17 revisions (10.6%). Six were secondary to progression of lateral compartment arthritis, 5 for persistent pain, 3 for femoral component aseptic loosening, 2 polyethylene dislocations, and 1 deep infection. The mean time to revision was 4 years (range 0.1-11). The survivorship free from revision at minimum 10-year follow-up was 85%. At final follow-up, the mean Knee Society Knee Score was 93 (range 66-100) and the mean functional score was 80 (range 30-100).

Conclusion

This single surgeon series demonstrated a survivorship of 85% at minimum 10-year follow-up. These results are comparable to published data from North America, but survivorship is lower than European series.

Section snippets

Patients and Methods

After Institutional Review Board approval, the Mayo Clinic prospective total joint registry was queried to identify all patients who underwent UKA performed by a single arthroplasty surgeon (R.J.S.) between January 2007 and August 2021. During this time, the senior author performed 430 medial compartment mobile-bearing UKAs. Of the 430 UKAs, 134 patients (157 knees) were eligible for inclusion in this study based on the date of their index surgery for a minimum time from implantation of 10

Revisions

There were 17 reoperations (11%) for any reason at minimum 10-year follow-up (Table 2). The mean time to reoperation was 4 years (range 0.1-10.5). Sixty percent of failures occurred within 3 years, with a second peak at 7 years (3 failures) and a third at 10 years (2 failures) (Fig. 1).

Reasons for reoperation included progression of lateral compartment OA (6 knees), persistent pain (5 knees), aseptic femoral component loosening (3 knees), polyethylene dislocation (2), and deep infection (1

Discussion

UKA is the best surgical option for select patients with monocompartmental knee arthritis. With improved UKA designs and techniques, along with an increased pressure to deliver cost-effective health care, we should continue to see an increase in utilization of UKA [11,12]. Determining the survivorship of past designs and studying the reasons for failures will improve current and future surgical outcomes. There are limited data on the mid-term to long-term results of mobile-bearing UKA in North

References (26)

S. Akizuki et al.
In vivo determination of kinematics for subjects having a Zimmer unicompartmental high flex knee system
J Arthroplasty
(2009)
A.J. Price et al.
Rapid recovery after oxford unicompartmental arthroplasty through a short incision
J Arthroplasty
(2001)
M.E. Neufeld et al.
A comparison of mobile and fixed-bearing unicompartmental knee arthroplasty at a minimum 10-year follow-up
J Arthroplasty
(2018)
D.L. Riddle et al.
Yearly incidence of unicompartmental knee arthroplasty in the United States
J Arthroplasty
(2008)
J.M. Hurst et al.
Radiographic comparison of mobile-bearing partial knee single-peg versus twin-peg design
J Arthroplasty
(2015)
D. Shakespeare et al.
The oxford medial partial knee replacement. The rationale for a femur first technique
Knee
(2012)
R. Chau et al.
Tibial component overhang following unicompartmental knee replacement--does it matter?
Knee
(2009)
T.W. Hamilton et al.
Evidence-based indications for mobile-bearing unicompartmental knee arthroplasty in a consecutive cohort of Thousand knees
J Arthroplasty
(2017)
J.P. van der List et al.
The Role of preoperative patient characteristics on outcomes of unicompartmental knee arthroplasty: a meta-analysis Critique
J Arthroplasty
(2016)
M.C. Lyons et al.
Unicompartmental versus total knee arthroplasty database analysis: is there a winner?
Clin Orthop Relat Res
(2012)

G.P. Hopper et al.

Participation in sporting activities following knee replacement: total versus unicompartmental

Knee Surg Sports Traumatol Arthrosc

(2008)

J. Newman et al.

Unicompartmental or total knee replacement: the 15-year results of a prospective randomised controlled trial

J Bone Joint Surg Br

(2009)

S. Ekhtiari et al.

Unicompartmental knee arthroplasty: survivorship and risk factors for revision: a population-based cohort study with minimum 10-year follow-up

J Bone Joint Surg Am

(2021)

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What Are the Contraindications for Lateral or Medial Unicondylar Knee Arthroplasty?
2025, Journal of Arthroplasty
Excellent 10-Year survivorship of robotic-arm-assisted unicompartmental knee arthroplasty
2024, Journal of Orthopaedics
Citation Excerpt :
Some studies have found lower survivorship rates than this current study or have found limited advantages to robotic assistance.15,16 In another longer-term outcomes study by Carlson et al., they found 85% survivorship at a minimum of 10 years (mean, 11.4 and range, 10.0 to 13.8).15 However, the implants utilized in the aforementioned study were different than the ones analyzed in the current study, and the surgical technique varied as robotic assistance was not utilized.
Robotic-arm-assisted unicompartmental knee arthroplasty (UKA) is an excellent solution for patients suffering from single-compartment knee arthritis. While outcomes tend to be favorable for UKAs, revision operations, commonly due to component malpositioning and malalignment resulting in accelerated wear, are a major concern. Intraoperative technologies, such as robotic assistance, can help better ensure that implants are positioned based on a patient's specific anatomy and mechanical physiology. However, long-term survivorship and patient-reported satisfaction with robotic-assisted UKAs are limited. Therefore, the purpose of this study was to assess the 10-year outcomes of patients who underwent robotic-arm-assisted unicompartmental knee arthroplasty. Specifically, we evaluated: 1) 10-year survivorships; 2) patient satisfaction scores; and 3) re-operations.
From a single surgeon and single institution, 185 patients who had a mean age of 65 years (range, 39 to 92) and a mean body mass index of 31.6 (range, 22.4 to 39) at a mean of 10 years follow-up were evaluated (range, 9 to 11). For all patients, the same robotic-assistive device was utilized intraoperatively, and all patients underwent standardized physical therapy and received standardized pain control management. Then 10-year survivorships with Kaplan-Meir curves, patient satisfaction evaluations with a 5-point Likert scale, and re-operations were assessed as primary outcomes.
Overall implant survivorship was 99%, with only two patients requiring revision surgery. There was one patient who was converted to a total knee arthroplasty, while the other patient underwent polyethylene exchange at 5 weeks for an acute infection with successful implant retention. Overall, 97% of the patients were satisfied with their postoperative outcomes, with 81% of patients reporting being very satisfied. There were two other patients who required arthroscopic intervention: one to remove a cement loose body, the other to remove adhered scar from the fat pad and the anterior cruciate ligament.
This study is one of the first to provide longer-term (mean 10-year) survivorship and patient-reported satisfaction outcomes for robotic-assisted UKA patients. These data show strong support for utilizing this surgical technique, as nearly all patients maintained their original prostheses and reported being satisfied after a mean of 10 years. Therefore, based on these results, we recommend the use of robotic assistance when performing UKAs.
Catastrophic Femoral Component Failure of a Unicompartmental Knee Arthroplasty
2024, Arthroplasty Today
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Successful medial UKA is ideally performed in patients with isolated medial compartment osteoarthritis with stable ligamentous examination, correctable deformity, and preserved range of motion with <15-degree flexion contracture [12]. UKA is a technically demanding procedure with current 10-year survivorship ranging from 85% to 98% and higher surgeon volumes correlating with a lower risk of revision surgery [13-16]. UKA complications include aseptic loosening, bearing dislocation, polyethylene wear, tibial fractures, osteoarthritis progression, infection, and unexplained pain.
We report a case of previously undescribed medial unicompartmental knee arthroplasty failure due to femoral component implant fracture. The patient experienced sudden pain and locking while ambulating 8 years postoperatively. Radiographs revealed catastrophic femoral component failure with a transverse break through the metal. The patient underwent revision to total knee arthroplasty. At 1-year follow-up, the patient had no pain and a range of motion of 130 degrees. Particular attention should be paid to obtaining adequate femoral component posterior flange fixation during unicompartmental knee arthroplasty. Patient education regarding maintaining a healthy weight is crucial to preventing this complication.
Femur-First Technique for Mobile Bearing Unicompartmental Knee Arthroplasty Results in Decreased Implant Variability and Early Improvements in Function and Survivorship
2023, Journal of Arthroplasty
Higher failure rates of unicompartmental knee arthroplasty (UKA) are seen with lower surgical volume. Surgical techniques that introduce less variability improving implant positioning may lead to improved survivorship. A femur-first (FF) technique has been described, but survivorship data compared to traditional tibia-first (TF) technique are under-reported. We report the results of mobile-bearing UKA using the FF technique compared to the TF technique with emphasis on implant position and survivorship.
A total of 430 UKAs were performed by a single surgeon between 2007 and 2020. After 2012, there were 141 consecutive UKAs performed with the FF technique which were compared with 147 consecutive UKAs prior. Mean follow-up was 6 years (range, 2 to 13 years), average age was 63 years (range, 23 to 92 years), and there were 132 women. Postoperative radiographs were reviewed to determine implant positioning. Survivorship analyses were performed using Kaplan-Meier curves.
The FF resulted in significantly thinner polyethylene (3.4 ± 0.7 mm versus 3.7 ± 0.9 mm) (P = .002) and 4 mm or less bearing thickness in 94% of cases. At 5 years, there was an early trend toward improved survivorship free from component revision (98% for the FF group and 94% for the TF [P = .35]). The FF cohort had higher Knee Society Functional scores at final follow-up (P < .001).
Compared to traditional TF technique, the FF was more bone-preserving and improved radiographic positioning. The FF technique is an alternative method for mobile-bearing UKA and was associated with an improvement in implant survivorship and function.
Revision of unicompartmental knee arthroplasty: a systematic review
2024, BMC Musculoskeletal Disorders
Clinical outcomes, complications, and survivorship for unicompartmental knee arthroplasty versus total knee arthroplasty in patients aged 80 years and older with isolated medial knee osteoarthritis: a matched cohort analysis
2023, Archives of Orthopaedic and Trauma Surgery

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: Investigation performed at the Mayo Clinic, Rochester, MN.

: One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to https://doi.org/10.1016/j.arth.2022.02.066.

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Proceedings of The Knee Society 2021Minimum 10-Year Survivorship of Mobile-Bearing Unicompartmental Arthroplasty: Single Surgeon, North American Non-Designer Consecutive Series

Abstract

Background

Methods

Results

Conclusion

Section snippets

Patients and Methods

Revisions

Discussion

J Arthroplasty

J Arthroplasty

J Arthroplasty

J Arthroplasty

J Arthroplasty

Knee

Knee

J Arthroplasty

J Arthroplasty

Unicompartmental versus total knee arthroplasty database analysis: is there a winner?

Clin Orthop Relat Res

Participation in sporting activities following knee replacement: total versus unicompartmental

Knee Surg Sports Traumatol Arthrosc

Unicompartmental or total knee replacement: the 15-year results of a prospective randomised controlled trial

J Bone Joint Surg Br

Unicompartmental knee arthroplasty: survivorship and risk factors for revision: a population-based cohort study with minimum 10-year follow-up

J Bone Joint Surg Am

Proceedings of The Knee Society 2021
Minimum 10-Year Survivorship of Mobile-Bearing Unicompartmental Arthroplasty: Single Surgeon, North American Non-Designer Consecutive Series