Preoperative Patellofemoral Chondromalacia is Not a Contraindication for Fixed-Bearing Medial Unicompartmental Knee Arthroplasty

Background

Patellofemoral chondromalacia (PFCM) has historically been considered a contraindication for unicompartmental knee arthroplasty (UKA), but there is limited data assessing PFCM's impact on the results of fixed-bearing UKA. Our objective was to assess the impact of medial patellar and/or medial trochlear PFCM on overall and patellofemoral-specific 2-year outcomes after fixed-bearing medial UKA.

Medial Unicompartmental Knee Arthroplasty in Patients Less Than 55 Years Old: Minimum of Two Years of Follow-Up

Eighty-five fixed bearing medial unicompartmental arthroplasties were performed in 42 men and 33 women with a mean age of 49 years (range, thirty-three to fifty-five years old) at the time of surgery. At a mean of 4.0 years (range two to twelve years), the mean pre-operative Knee Society score improved from 49 to 95.1 points (P< 0.0001) and the mean UCLA activity score was 7.5 (range 5 to 9). Three knees underwent revision to a total knee arthroplasty; two for arthritic progression in the lateral compartment and one for pain. At the time of final follow-up, two knees (2.4%) demonstrated progressive Grade 4 arthritis of the patellofemoral compartment but were asymptomatic. There was no radiographic evidence of loosening, osteolysis, or premature polyethylene wear. Estimated survivorship was 96.5% at 10 years. UKA offered excellent early outcomes in this cohort of younger, active patients.     

15-Year Follow-Up of Mobile Bearing Medial Unicompartmental Knee Arthroplasty

IntroductionMedial unicompartmental knee arthroplasty (UKA) is a successful treatment for antero-medial osteoarthritis. However, there are few published studies on the long-term survival of this procedure. The purpose of this study was to review the 15-year minimum outcomes and survival of a mobile-bearing medial UKA.MethodsA retrospective review was performed between July 2004 and December 2006 of all patients who underwent a medial UKA eligible for a minimum of 15-year follow-up. The initial query revealed 299 patients (349 knees). One hundred-seventeen patients died or were lost to follow-up, leaving 182 patients (219 knees) for analyses. Clinical outcomes and survivorship were analyzed.ResultsThere were 59 implant-related reoperations which occurred at a mean of 10 years (range, 0 to 16 years). The most common reasons for reoperation were arthritic progression (9.1%) and aseptic loosening (9.1%). The 10-year survival with revision to TKA was 89% (95% confidence interval: 86% to 92.4%), and the 15-year survival was 84.1% (95% confidence interval: 80.3% to 88%). There were no statistically significant differences in survival between sex, body mass index, and age. Patients who were not revised had statistically significant improvements in knee range of motion and Knee Society scores.ConclusionsThis study found similar long-term survival of a medial mobile-bearing UKA to published total knee arthroplasty outcomes. The implant evaluated in this study has undergone subsequent improvements in instrumentation and design. Further analyses should be performed on the long-term outcomes of the current implant platform.     

Predictors of Satisfactory Outcomes With Fixed-Bearing Lateral Unicompartmental Knee Arthroplasty: Up to 7-year Follow-Up

BackgroundThere is little literature available examining factors that may predict functional recovery after lateral unicompartmental knee arthroplasty (UKA). The purpose of this study was to report short to mid-term effectiveness and evaluate predictors of better outcome following lateral UKA.MethodsWe retrospectively reviewed 248 patients (260 knees) who underwent lateral UKA from January 2013, with a mean 5-year follow-up. The primary outcome measures comprised the Hospital for Special Surgery (HSS) score and patient satisfaction. Multivariate regression analyses were implemented to investigate associations between these factors with a satisfactory outcome. Implant survival was estimated by Kaplan-Meier analysis.ResultsComplete follow-up was available for 186 patients (198 knees). At last follow-up, the HSS scores were changed from 52.1 (range, 38-80) preoperatively to 85.6 (range, 61-98) (P < .001), The OKS improved from 22.8 (range, 16-32) preoperatively to 42.7 (range, 30-47) postoperatively (P < .01). The 5-year survival was 99.5%. The multivariate analysis showed that the following factors tended to obtain a satisfactory outcome: higher proportion of ASA class I (P < .001), diagnosis of primary OA (P = .007), postoperative limb alignment (P = .007), and higher preoperative HSS score (P = .019). Patients with valgus 9°-12° reported the highest HSS scores among different subgroups (P < .001).ConclusionFollowing lateral UKA, postoperative outcomes were satisfactory in patients with lower ASA scores, diagnosis with primary OA, higher preoperative HSS scores and those with postoperative valgus alignment. It is important to understand these correlations to help appropriate patient selection to obtain optimal function after lateral UKA.     

Unicompartmental Knee Arthroplasty vs Total Knee Arthroplasty for Medial Compartment Arthritis in Patients Older Than 75 Years: Comparable Reoperation,Revision, and Complication Rates

Background

Prior studies comparing unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) in the elderly are limited by heterogeneity in arthritic disease patterns and patient selection. We report the results of UKA and TKA in patients 75 years and older with isolated medial compartmental arthritis, with special emphasis on immediate postoperative recovery, complications, reoperation rates, and implant survivorship at midterm follow-up.

A Comparison of Mobile and Fixed-Bearing Unicompartmental Knee Arthroplasty at a Minimum 10-Year Follow-up

Background

The long-term survivorship and functional outcomes of the mobile-bearing (MB) compared to the fixed-bearing (FB) unicompartmental knee arthroplasty (UKA) implant design remain a topic of debate. The aim of the current study was to compare the survivorship and functional outcomes of MB and FB UKA at a minimum 10-year follow-up.

Long-Term Functional Outcomes and Quality of Life at Minimum 10-Year Follow-Up After Fixed-Bearing Unicompartmental Knee Arthroplasty and Total Knee Arthroplasty for Isolated Medial Compartment Osteoarthritis

BackgroundThe aim of this study is to compare the long-term functional outcome and quality of life between total knee arthroplasty (TKA) and fixed-bearing unicompartmental knee arthroplasty (UKA) for the treatment of isolated medial compartment osteoarthritis.MethodsBetween 2000 and 2008, a total of 218 patients underwent primary UKA at our tertiary hospital. A TKA group was matched through 1:1 propensity score matching and adjusted for age, gender, body mass index, preoperative knee flexion, and function scores. All patients had medial compartment osteoarthritis. The patients were assessed with the range of motion, Knee Society Knee Score and Knee Society Function Score, Oxford Knee Score, Short Form-36 physical component score (PCS) and mental component score preoperatively, at 6 months, 2 years, and 10 years. Patients’ satisfaction, expectation fulfillment, and minimal clinically important difference were analyzed.ResultsThere were no differences in baseline characteristics between groups after propensity score matching (P > .05). UKA had greater knee flexion at all time points. Although the Knee Society Function Score was superior in UKA by 5.5, 3, and 4.3 points at 6 months, 2 years, and 10 years, respectively (P < .001), these differences did not exceed the minimal clinically important difference (Knee Society Knee Score 6.1). There were no significant differences in the Oxford Knee Score and Short Form-36 physical component score/mental component score. At 10 years, similar proportions of UKA and TKA were satisfied (90.8% vs 89.9%, P = .44) and had expectation fulfillment (89.4% vs 88.5%, P = .46). Between 2 and 10 years, all function scores deteriorated significantly for both groups (P < .01).ConclusionUKA and TKA are excellent treatment modalities for isolated medial compartment osteoarthritis, with similar functional outcomes, quality of life, and satisfaction at 10 years.     

Medial Unicompartmental Knee Arthroplasty After Failed Open-Wedge High Tibial Osteotomy

BackgroundControversy exists whether or not a previous high tibial osteotomy (HTO) influences the outcome and survival of a unicompartmental knee arthroplasty (UKA). The aim of this retrospective study was to evaluate clinical, radiological, and functional outcomes of UKA after failed open-wedge HTO compared with UKA with no previous HTO.MethodsBetween 2001 and 2017, 24 post-HTO UKAs (group A) with an average follow-up of 8.1 years (range: 5 to 13) were compared with a control group of 30 patients undergoing simple UKA (group B) with an average follow-up of 9.5 years (range: 2 to 16). All patients were evaluated preoperatively and postoperatively using Knee Society Score, University of California at Los Angeles Activity Score, Western Ontario and McMaster University Osteoarthritis Index, and through objective evaluation. Mechanical coronal alignment and Caton-Deschamps index were measured both preoperatively and postoperatively.ResultsIn both groups, Knee Society Score, University of California at Los Angeles Activity Score, and Western Ontario and McMaster University Osteoarthritis Index scores significantly improved at follow-up (P < .001). In addition, statistically significant greater improvements in clinical and functional scores were reported in group B compared with group A (P < .001). No statistically significant differences concerning postoperative mechanical axis were observed between groups (2.7° and 3.2°, respectively, P = .27) and with regard to Caton-Deschamps index (1.0° and 1.1°, respectively, P = .44).ConclusionThis study demonstrated improvements in clinical and functional outcomes compared with preoperatory status in both groups irrespective of a previous HTO. A prior HTO was a determinant for having reduced postoperative clinical and functional outcomes after UKA.     

Age and Outcomes of Medial Meniscal-Bearing Unicompartmental Knee Arthroplasty

Background

National joint registries report increasing revision rates with decreasing patient age for all types of joint arthroplasty. This study aimed to explore the effect of age on function and revision risk in patients undergoing medial meniscal-bearing UKA.

Lateral Meniscal Injury After a Successful Medial Unicompartmental Knee Arthroplasty

A case of an active 52-year-old woman who, after a medial unicompartmental knee arthroplasty, began complaining of lateral joint line pain and a persistent knee effusion. A lateral meniscal tear was diagnosed clinically, and she underwent an arthroscopic partial meniscectomy that resolved her problems. This case demonstrates the importance of considering a meniscal problem as the cause of any unexplained joint line pain in the unoperated compartment after a successful unicompartmental knee arthroplasty and not simply attributing it to progression of degenerative change within the lateral compartment.     

Outcomes After Arthroscopic Evaluation of Patients With Painful Medial Unicompartmental Knee Arthroplasty

Background

Persistent pain after medial unicompartmental knee arthroplasty (UKA) is a prevailing reason for revision to total knee arthroplasty (TKA). Many of these pathologies can be addressed arthroscopically. The purpose of this study is to examine the outcomes of patients who undergo an arthroscopy for any reason after medial UKA.

Comparison of High Tibial Osteotomy and Unicompartmental Knee Arthroplasty at a Minimum Follow-Up of 3 Years

The purpose of this study was to compare clinical outcomes including return to recreational activities (cycling, swimming, exercise walking, dancing, jogging, and mountain climbing) after opening-wedge high tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA). Clinical outcomes were assessed using Tegner activity scores, ranges of motion, and Lysholm knee scores. In both groups, the number of patients participating in recreational activities was significantly reduced after surgery, but without a significant intergroup difference (1.3 activities in HTO group and in 1.6 activities in UKA group). Average Tegner activity scale scores, ranges of motion, and Lysholm knee scores did not show significant differences between the 2 groups. This study identified no significant differences between HTO and UKA for medial unicompartmental osteoarthritis in terms of return to recreational activity and short-term clinical outcomes.     

The Role of Patient Characteristics on the Choice of Unicompartmental versus Total Knee Arthroplasty in Patients With Medial Osteoarthritis

Background

Medial unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are both viable treatment options for medial osteoarthritis (OA). However, it remains unclear when to choose for which arthroplasty treatment. Goals of this study were therefore to (1) compare outcomes after both treatments and (2) assess which treatment has superior outcomes in different patient subgroups.

Central Implantation of the Femoral Component Relative to the Tibial Insert Improves Clinical Outcomes in Fixed-Bearing Unicompartmental Knee Arthroplasty

BackgroundThe direct relationship between clinical outcomes and femoral component positioning relative to a tibial insert remains unknown. We determined whether the femoral component position relative to the tibial insert could affect clinical outcomes after fixed-bearing unicompartmental knee arthroplasty (UKA).MethodsThe femoral component position relative to the tibial insert of 66 patients with anteromedial osteoarthritis and osteonecrosis of the knee who underwent fixed-bearing UKA was assessed at 2 weeks postoperatively. We classified patients according to the contact point of the femoral component with the tibial component: group M (medial), 18 knees; group C (central), 30 knees; and group L (lateral), 18 knees. Patient-derived clinical scores using the 2011 Knee Society Score were also assessed preoperatively and at 2 years postoperatively and compared among the 3 groups using the analysis of variance.ResultsThe average 2-year postoperative “symptom” and “patient satisfaction” scores based on the 2011 Knee Society Score were significantly higher in group C than in group M or group L.ConclusionCentral implantation of the femoral component relative to the tibial insert plays an important role in decreasing pain and could result in better patient satisfaction after fixed-bearing UKA at 2 years postoperatively. Surgeons should set the femoral component at the center relative to the tibial insert for better patient satisfaction and higher active knee flexion after fixed-bearing UKA.     

Midterm Survivorship and Patient Satisfaction of Robotic-Arm-Assisted Medial Unicompartmental Knee Arthroplasty: A Multicenter Study

Background

Studies have showed improved accuracy of lower leg alignment, precise component position, and soft-tissue balance with robotic-assisted unicompartmental knee arthroplasty (UKA). No studies, however, have assessed the effect on midterm survivorship. Therefore, the purpose of this prospective, multicenter study was to determine midtem survivorship, modes of failure, and satisfaction of robotic-assisted medial UKA.

A Review of Mobile Bearing Unicompartmental Knee in Patients Aged 80 Years or Older and Comparison With Younger Groups

The Knee Society scores and other outcome measures in patients aged 80 years or older (n = 51) who had mobile bearing unicompartmental knee arthroplasty performed in Tayside, Scotland, were reviewed retrospectively. The results were compared with those in younger age groups: “younger than 60 years” (n = 110), “60 to 69 years” (n = 164), and “70 to 79” years (n = 145). In the study group, the mean Knee Society knee score (objective) at 1-year follow-up was 85.21, compared with a mean of 77.82 for younger-than-60-years age group, 81.28 for 60-to-69-years age group, and 87.33 for 70-to-79-years age group. The differences between the knee scores in the study group and the other groups were not statistically significant. Revision rate and survival of implant were not different between the groups. We conclude that patients aged 80 or older should be considered for mobile bearing unicompartmental knee arthroplasty if they fulfill the described criteria.     

Results of Unicompartmental Knee Arthroplasty With Cemented,Fixed-Bearing Prosthesis Using Minimally Invasive Surgery

The aim of this study was to evaluate the intermediate-term survivorship of cemented fixed-bearing unicompartmental knee arthroplasty (UKA). One hundred twenty-eight consecutive UKAs in 98 patients were performed by a single surgeon with “Allegretto” UKA prostheses. Six patients died and 5 were lost to follow-up, leaving 87 patients (116 knees) with an average follow-up of 5.7 years (range, 3-8 years). At the latest follow-up, the survival rate was 92.2%; average clinical and functional knee society scores improved from 50 and 64 points preoperatively to 89 and 88 points, respectively; and average total knee score was 171 (range, 94-200). Radiographic follow-up demonstrated average alignment of 3° valgus (range, 6° varus to 7° valgus). Ninety-two percent of the patients indicated satisfaction with the procedure. Nine knees failed requiring revision at an average of 40.4 months. We are encouraged with the satisfactory results, considering the broader spectrum of selected patients.     

Comparison of Fixed-Bearing and Mobile-Bearing Unicompartmental Knee Arthroplasty: A Systematic Review and Meta-Analysis

BackgroundPrior studies have compared fixed-bearing unicompartmental knee arthroplasty (FB-UKA) with mobile-bearing UKA (MB-UKA), suggesting that both procedures have good clinical outcomes. However, which treatment is more beneficial for patients is controversial. The purpose of our study is to evaluate the postoperative outcomes, including the revision rate, complications, functional results, range of motion, and femoral-tibial angle, between the 2 procedures.MethodsWe searched the MEDLINE, EMBASE, Cochrane Library, and Web of Science databases starting from August 2017 to May 2018. The publication date of articles was not restricted. Before we submit our contribution, we have re-searched it again. Articles that directly compared the postoperative outcomes of the 2 prosthesis type were included.ResultsA total of 15 comparative studies were included in our meta-analysis. The pooled data indicated no differences between the 2 operation modes in terms of revision rates, complications, and knee function, but earlier failure occurred more frequently with the MB design.ConclusionBoth the arthroplasty types provided satisfactory clinical results for patients with classic indications. However, MB-UKA tended to fail in early postoperative years whereas fixed-bearing UKA in later postoperative years. Therefore treatment options should be carefully considered for each patient, and surgeons should still use their personal experience when deciding between these options.     

Octogenarians Undergoing Medial Unicompartmental Knee Arthroplasty Have Similar Patient-Reported Outcomes as Their Younger Counterparts

BackgroundAs a procedure with lower surgical morbidity, unicompartmental knee arthroplasty (UKA) may present a practical solution for elderly patients with unicompartmental arthritis. However, few studies have analyzed the results of UKA in the extreme elderly. This study compared the functional and perioperative outcomes between octogenarians and age-appropriate controls undergoing UKA.MethodsProspectively collected data of 44 patients aged ≥80 years who underwent unilateral UKA were analyzed. Each octogenarian was matched 1:3 with 132 patients aged 65-74 years using propensity scores adjusting for gender, body mass index, Charlson comorbidity index, and preoperative scores. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and Short Form-12 were collected preoperatively and 2 years postoperatively. Complications, reoperations, readmissions, and unplanned visits were recorded up to 1 year postoperatively.ResultsThe mean age was 70.0 ± 2.7 years in the control group and 83.0 ± 3.0 years in the octogenarian group (P < .001). The percentage of outpatient procedures was comparable (control 50.0%; octogenarian 45.5%; P = .601). With the exception of poorer Short Form-12 physical scores in octogenarians at 2 years (39.4 ± 14.1 vs 44.9 ± 9.2, P = .028), there was no difference in final postoperative scores or improvement in scores between the groups. The rate of complications, reoperations, readmissions, and emergency room visits was also similar. The five-year survivorship was 97% in the control group and 93% in the octogenarian group (P = .148).ConclusionOctogenarians undergoing UKA can experience clinical outcomes that are similar to those of their younger counterparts. The clinical trajectory outlined may help clinicians provide valuable prognostic information to elderly patients and guide preoperative counseling.     

Improved Survival of Computer-Assisted Unicompartmental Knee Arthroplasty: 252 Cases With a Minimum Follow-Up of 5 Years

Background

Unicompartmental knee arthroplasty (UKA) is an underutilized implant for medial tibiofemoral arthritis despite proven benefits in performance and reduced complications. This is likely related to registry recorded higher revision rates compared with total knee arthroplasty. It is our feeling that better component alignment resulting from the usage of computer-assisted surgery should improve longer-term functional results and survival of UKAs.