Unicompartmental Knee Arthroplasty and Patellofemoral Resurfacing Arthroplasty


36 Unicompartmental Knee Arthroplasty and Patellofemoral Resurfacing Arthroplasty


Waleed Albishi MBBS, Paul Jamieson MD, Ivan Kamikovski MD, and Geoffrey Dervin MD


Division of Orthopaedic Surgery, Department of Surgery, University of Ottawa, Ottawa, ON, Canada


Clinical scenario 1



  • An active 58‐year‐old female has lateral knee pain that is disabling.
  • She had lateral meniscectomy as a teenager.
  • Her flexion is to 130° and there is no contracture, and ligaments are otherwise stable.

Clinical scenario 2



  • A 46‐year‐old woman with a medical history of multiple patella dislocations with previous lateral release.
  • Progressive worsening of anterior knee pain, aggravated by climbing and descending stairs and rising from sitting position. Injections and physical therapy ineffective.
  • Left knee range of motion is from 0–20° flexion. Lateral patella tracking and stable knee ligaments. Her radiographs show a severe lateral patellofemoral osteoarthritis (PF OA).

Top three questions



  1. Does unicompartmental knee arthroplasty (UKA) provide better patient‐reported outcomes despite worse survivorship than total knee arthroplasty (TKA) in patients under age 60 with isolated medial compartment OA?
  2. Is lateral UKA a better alternative to TKA for patients under age 60 with respect to functional outcome?
  3. What are the patient‐reported outcomes for patellofemoral arthroplasty (PFA) versus TKA for patients under age 55 with isolated PF OA ?

Question 1: Does unicompartmental knee arthroplasty (UKA) provide better patient‐reported outcomes despite worse survivorship than total knee arthroplasty (TKA) in patients under age 60 with isolated medial compartment OA?


Rationale


UKA has been an accepted alternative to TKA since the 1970s. It is attractive because of its ligament and bone preserving surgery, shorter and simpler rehabilitation, and some findings suggesting improved function and satisfaction when compared to TKA. However, registry data have consistently shown nearly double the revision rate to that of TKA across all age categories, especially in those under the age of 60, fueling the debate as to the role for UKA in this age group.


Clinical comment


Many patients under the age of 60 with isolated medial compartment OA which has failed conservative management have the surgical option of either medial UKA or TKA. Although of limited strength, recent literature supports the notion that UKA produces as good and sometimes more favorable reported patient‐reported outcome measures (PROMs) compared with TKA and yet reported survivorship is typically only half as good.


Available literature and quality of the evidence


The available literature to answer this question is limited to level III retrospective observational studies, level IV case series, and systematic reviews of the former.


Findings


Multiple level III and IV studies have been completed to ascertain the survivorship of UKA in young patients, and there are mixed results in the literature. The evidence is mixed between the designer center series, cohort groups, and national registries. In 2011, Pandit et al. published a retrospective review of their first 1000 phase three Oxford medial UKAs implanted at the designer center and subdivided the patients into those younger (245 patients) and older than 60 (755 patients) at age of implantation. They found no difference in 10‐year survivorship between the two groups, 97.3% (91.3–100%) and 95.1% (90.8–99.3%), respectively, with functional scores equal or better in the under 60 years of age group.1 Several other case series have been published with similar outcomes and survivorship beyond 10 years.25 A 2018 systematic review by Kleeblad et al. aimed to compare outcomes and revision rates between UKA and TKA in patients under the age of 65.6 To calculate revision rates, the authors identified 21 cohort studies reporting data on 2224 UKAs and 33 cohort studies reporting data on 4737 TKAs. The overall UKA revision rate was 8.2% at a mean follow‐up of 9.8 years and an annual revision rate (ARR) of 1.00 (95% confidence interval [CI]: 0.77–1.30). Alternatively, the overall TKA revision rate was 6.95% at a mean follow‐up of 8.4 years and an ARR of 0.53 (95% CI: 0.36–0.78). Few studies have specifically assessed survivorship of UKA in very young patients. Parratte et al. performed a retrospective review of 25 patients under the age of 50 who underwent medial UKA, and although they found that the mean KSS score improved from 54 to 89 preoperatively, their 12‐year survival rate was 80.6%.7 The 2018 annual report of the Australian Orthopaedic Association National Joint Replacement Registry looking at 52 000 primary UKAs reported the cumulative percent revision of primary UKAs and found that patients aged between 55–64 had a 15.9% (range 15.3–16.6%) revision rate at 10 years and 30.4% (range 28.0–33.0%) at 17 years. Further, patients with UKA under the age of 55 had a cumulative percent revision of 22.8% (21.7–23.9%) at 10 years and 39.4% (36.6–41.4%) at 17 years.8 Conversely, TKA patients between the ages of 55 and 64 had an 11.8% (11.1–12.5%) revision rate and patients less than 55 had a 17.8% (16.4–19.3%) revision rate at 17 years.


Regarding functional outcomes, in the Kleeblad et al. systematic review, significantly higher overall ROM (125° vs 114, p = 0.004) as well as higher Knee Society Scores at long‐term follow‐up were found in the UKA group compared to the TKA group (88.1 and 85.8, respectively, p = 0.04).6 A retrospective case series by Walker et al. of 118 consecutive Oxford medial UKAs in patients aged 60 or younger found that 93% of patients returned to activity postoperatively at minimum two‐year follow‐up and 62% of patients were defined as “very active” based on the UCLA score of ≥7.9 Von Keudell et al. performed a retrospective age matched cohort analysis of 485 knee surgeries with a minimum three‐year follow‐up and found that in patients between the ages of 55 and 64 higher satisfaction was found in the UKA group with 93% of patients having excellent/good patient satisfaction compared to 89% in the TKA group.10 In those under the age of 55, 96% of patients with UKA had excellent/good patient satisfaction compared to 81% in the TKA group. Goh et al. published a retrospective matched cohort analysis of 160 patients under the age of 55 who underwent TKA and found that at both six months and two years patients in the UKA group had significantly greater ROM than those who underwent a TKA (128° ± 11° vs 117° ± 15°, respectively, at two years, p <0.001). They did not, however, identify any difference in functional outcomes or patient satisfaction scores.11


At this time, UKA in patients under the age of 60 requires careful patient selection, meticulous surgical technique, and adequate surgical experience and also benefits from a shared decision‐making process between the patient and surgeon. To this end, several authors have developed surgical decision tools to provide support and information to patients deciding between undergoing TKA and UKA.1214 Prospective randomized studies, some of which are ongoing, are required to better answer this question.15


Question 2: Is lateral UKA a better alternative to TKA for this patient under age 60 with respect to functional outcome?


Rationale


Despite the potential benefits of UKA as a bone preservation technique with faster recovery and lower morbidity, lateral UKA accounts for less than 1% of all knee replacement procedures.


Clinical comment


It is critical to appreciate whether the benefits to patients outweigh the concerns of technical complexity and survivorship.


Available literature and quality of the evidence

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Nov 28, 2021 | Posted by in ORTHOPEDIC | Comments Off on Unicompartmental Knee Arthroplasty and Patellofemoral Resurfacing Arthroplasty
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