Preoperative Bone Marrow Edema Negatively Impacts 10-Year Outcomes After Unicompartmental Knee Arthroplasty

BackgroundThe purpose of this study was to investigate the association between the extent of subchondral bone marrow edema (BME), as classified by magnetic resonance imaging, and intermediate to long-term outcomes after unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis.MethodsWe enrolled 150 knees (144 patients) that underwent fixed-bearing UKA between April 2003 and December 2014 with a minimum follow-up of 5 years; the mean overall follow-up duration was 10 years (range, 5-18 years). We divided the patients into 2 groups based on the presence or absence of preoperative BME. Patients were also subdivided into 4 groups according to their BME scores determined by the magnetic resonance imaging Osteoarthritis Knee Score method. Clinical outcomes were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Forgotten Joint Score. Furthermore, survival rates and relevant risk factors that affect joint survivorship were analyzed.ResultsThe groups with BME demonstrated significantly worse postoperative WOMAC pain and Forgotten Joint Scores at the final follow-up than the group without BME (all P < .05). We also found significant differences among the scores of groups with different BME grades (all P < .05). Post hoc analysis demonstrated differences between groups 1 and 2, 1 and 3, 1 and 4, and 2 and 4 (all P < .05) with a significant correlation between postoperative clinical outcomes and the extent of BME (r = 0.430 [WOMAC pain], r = ?0.342 [Forgotten Joint Score]; P < .05). The survival rate was 95.4% for a mean period of 10 years for the UKAs, and the UKA survival was not associated with the presence of BME (P = .232; log-rank test).ConclusionAt a mean of 10 years, preoperative BME negatively impacted the clinical outcomes, especially pain, after UKA. However, UKA contributed to excellent survival rates for the same duration of follow-up, regardless of BME severity. Although this study does not provide any evidence that preoperative BME should be identified as a contraindication, evaluation of BME can provide crucial information about the expected outcomes.     

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.     

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.     

No Difference Unicompartmental Knee Arthroplasty for Medial Knee Osteoarthritis With or Without Anterior Cruciate Ligament Deficiency: A Systematic Review and Meta-analysis

BackgroundA functional intact anterior cruciate ligament (ACLI) is considered to be a prerequisite for unicompartmental knee arthroplasty (UKA). However, UKA has been shown to have good clinical efficacy in ACL-deficient (ACLD) knees at 3 to 10 years follow-up. Therefore, the role of ACLD in UKA remains controversial, and more evidence is needed to clarify the role of ACLD in UKA.MethodsPubMed, the Web of Science, EMBASE, and Cochrane Central were queried for articles comparing the results of the ACLD and ACLI groups after UKA. Outcomes of interest included the Tegner Activity Scale, the Oxford Knee Score (OKS), postoperative slope of the implant (PSI), the Knee Injury and Osteoarthritis Outcomes Score (KOOS), the Lysholm score, and revision rate. There were eight studies included. The mean age was 66 years (range 49 to 87 year old) and the mean follow-up time was 6.9 years (range 1.3 to 16.6 years). There was baseline comparability regarding mean age, duration of follow-up, and body mass index (P > .5) between the ACLD and ACLI groups.ResultsThe ACLD and ACLI groups had improved postoperative functional indicators, and that postoperative revision rate (mean difference [MD], 1.24; 95% confidence interval [CI], 0.75 to 2.04; P = .4), Tegner score (MD, ?0.1; 95% CI, ?0.26 to 0.05; P = .19), and Lysholm score (95% CI, ?2.46 to 7.32; P = .33) were similar between the groups, with no significant differences; however, the ACLD groups had significantly better KOOS Activities of Daily Living scores, with a significant difference (MD, 4.53; 95% CI, 1.75 to 7.3; P = .001). Also, there were no significant differences between two groups in the PSI, OKS, KOOS.ConclusionACL deficiency is not always a contraindication for UKA. With correct patient selection, UKA could be considered for medial knee osteoarthritis with ACL deficiency without antero-posterior instability, especially these people over 60 years of age.     

Does Unicompartmental Knee Replacement Offer Improved Clinical Advantages Over Total Knee Replacement in the Treatment of Isolated Lateral Osteoarthritis? A Matched Cohort Analysis From an Independent Center

BackgroundThe purpose of this study is to compare the functional and radiographic results, perioperative complications, satisfaction rate, and mid-term survivorship after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) for the treatment of lateral compartmental knee osteoarthritis (LCKO).MethodsBetween March 2007 and September 2017, we identified 35 patients with primary TKAs and 121 patients with lateral UKAs (LUKAs) for LCKO with a minimum follow-up of 2 years (mean 5.3 years, range 2-12.4). The matched variables were age, gender, operation side, body mass index, American Society of Anesthesiologist grade, initial diagnosis, osteoarthritis grade in lateral compartment, and follow-up time. All patients were assessed using the Oxford Knee Score, Hospital for Special Surgery score, range of motion, length of hospital stay, satisfaction, and complications. Survivorship of UKA and TKA implants was also compared.ResultsAt last follow-up, LUKA had a significantly better postoperative Oxford Knee Score, Hospital for Special Surgery score, range of motion, shorter length of hospital time, and higher satisfaction rate than matched TKA group. There were significant differences regarding patellar tendon injury (P = .043), superficial wound infection (P = .028), patellar snapping or impingement (P = .047), and stiffness (P < .001). Five-year survivorships free from revision were similar in both groups (99.2% vs 97.1%, P = .347).ConclusionLUKA for LCKO demonstrated more favorable 5-year results in comparison with TKA. Furthermore, LUKA achieved comparable mid-term survivorship and was less likely to suffer from wound infection and knee stiffness, although not overall surgical complications.     

Clinical Outcomes and Survivorship of Lateral Unicompartmental Knee Arthroplasty: Does Surgical Approach Matter?

Background

Lateral unicompartmental knee arthroplasty (UKA) has been shown to be an effective procedure to treat isolated lateral compartment osteoarthritis with excellent long-term survivorship. Whether a medial parapatellar approach or a lateral parapatellar approach is superior in lateral UKA is unknown. The purpose of this study was to determine if there is a difference in intermediate-term clinical outcomes in patients undergoing lateral UKA through a lateral vs medial parapatellar approach.

Preoperative Flexion Contracture Does Not Compromise the Outcomes and Survivorship of Medial Fixed Bearing Unicompartmental Knee Arthroplasty

BackgroundDespite the expanding indications for unicompartmental knee arthroplasty (UKA), the classic indication that limits flexion contracture to <5° in fixed bearing UKA excludes most patients with arthritic knees and has not been challenged in modern literature. This study compared the clinical outcomes between patients with severe flexion contracture and controls undergoing UKA.MethodsEighty seven medial fixed bearing UKAs performed in patients with severe (≥15°) flexion contracture were matched 1:1 with 87 controls without flexion or recurvatum deformity (−5°<extension<5°) using propensity scores to control for age, sex, BMI, Charlson comorbidity index, ASA class, and baseline patient-reported outcome measures (PROMs). Perioperative outcomes were recorded. Range of motion, Knee Society Score, Oxford Knee Score, SF-36, and patient satisfaction were assessed at 6 months and 2 years. Survivorship was recorded at mean 11.5 ± 3.2 years.ResultsPreoperative knee extension in the control and contracture groups was 0.9° ± 1.9° and 18.0° ± 3.5° (P < .001), respectively, whereas flexion was 122.8° ± 27.9° and 120.6° ± 13.6° (P = .502). The contracture group had poorer Knee Society functional (P = .023) and SF-36 physical score (P = .010) at 6 months. However, there was no difference in PROMs at 2 years. A similar proportion achieved the minimal clinically important difference for each PROM and was satisfied with surgery. Range of motion remained poorer in the contracture group and a higher percentage had residual contractures (P < .001). Ten-year survivorship was 94% and 97% in the control and contracture groups, respectively (P = .145).ConclusionAlthough patients with severe flexion contractures had a poorer range of motion and postoperatively, these patients attained comparable PROMs, satisfaction rates, and mid-term survivorship after UKA.Level of EvidenceIII, therapeutic study.     

Midterm Survivorship of Robotic-Assisted Lateral Unicompartmental Knee Arthroplasty

BackgroundLateral unicompartmental knee arthroplasty (UKA) is a popular alternative to total knee arthroplasty (TKA) for patients with isolated lateral compartment osteoarthritis. Few studies have investigated outcomes following robotic-assisted lateral UKA. The purpose of this study is to evaluate mid-term survivorship and patient-reported outcomes of robotic-assisted lateral UKA.MethodsA retrospective case series was conducted on all robotic-assisted lateral UKAs performed by a single surgeon between 2013 and 2019. Patient demographics, surgical variables, and Kozinn and Scott criteria were collected. Implant survivorship was estimated using the Kaplan-Meier method with all-cause reoperation and conversion to TKA as endpoints. Participating patients were assessed for patient satisfaction and the Forgotten Joint Score-12. Correlations between patient demographics and patient outcome scores were investigated.ResultsIn total, 120 lateral UKAs were identified, 84 of which met inclusion criteria, with a mean follow-up of 4.0 years (range 2.0-7.0). Five-year survivorship was 92.9% (95% confidence interval [CI] 84.5-96.7) with all-cause reoperation as the endpoint, and 100% (95% CI 95.0-100) with conversion to TKA as the endpoint. One patient was converted to TKA after the 5-year mark, resulting in a 6-year survival for conversion to TKA of 88.9% (95% CI 44.9-98.5). Average Forgotten Joint Score-12 score was 82.7/100, and patient satisfaction 4.7/5. Mean coronal plane correction was 2.5° ± 1.9° toward the mechanical axis. Neither final postoperative alignment nor failure to meet classic Kozinn and Scott criteria for UKA resulted in differences in patient-reported outcomes.ConclusionThe current study demonstrates high mid-term survivorship and excellent patient-reported outcomes with robotic-assisted lateral UKA. Robotic-assisted lateral UKA is a viable treatment option for isolated lateral compartment arthritis even in patients who do not meet classic indications.     

Unicompartmental Knee Arthroplasty Patients Have Lower Joint Awareness and Higher Function at 5 Years Compared to Total Knee Arthroplasties: A Matched Comparison

BackgroundThe purpose of this study was to evaluate postoperative outcomes at minimum 5-year follow-up in patients following unicompartmental knee arthroplasty (UKA) compared to a matched cohort of total knee arthroplasty (TKA) patients.MethodsPatients who had primarily medial compartment osteoarthritis (OA) who met criteria for medial UKA underwent TKA or medial UKA between 2014 and 2015 at a single institution, matched for age, sex, and body mass index. There were 127 UKAs in 120 patients and 118 TKAs in 116 patients included with minimum 5-year follow-up (range, 6 to 8). Mean age was 69 years (range, 59 to 79) and 71 years (range, 62 to 80) in the UKA and TKA groups, respectively (P = .049).ResultsPatients who underwent UKA had significantly higher mean (±SD) Forgotten Joint Scores (87 ± 20 versus 59 ± 34, P < .001); higher Knee Society Scores (88 ± 14 versus 75 ± 21, P < .001); and lower Numeric Pain Rating Scores (0.8 ± 1.6 versus 1.9 ± 2.2, P < .001). Survivorship free from all-cause revision was 96% (95% CI = 93%-99%) and 99% (95% CI = 97%-100%) at 5 years for TKA and UKA, respectively (P = .52). There were 8 both component revisions in the TKA group within 5 years from the date of surgery and 2 UKA conversions to TKA after 5-year follow-up.ConclusionPatients who have medial compartment OA and underwent UKA had significantly lower joint awareness, decreased pain, improved function, and higher satisfaction compared to matched TKA patients at minimum 5-year follow-up while maintaining excellent survivorship.     

Comparison of Long-Term Survival Analysis Between Open-Wedge High Tibial Osteotomy and Unicompartmental Knee Arthroplasty

BackgroundTo compare unicompartmental knee arthroplasty (UKA) and open-wedge high tibial osteotomy (OWHTO) in a long-term follow-up propensity score matching analysis.MethodsPatients who underwent UKA or OWHTO for unilateral medial unicompartmental osteoarthritis (OA) between 2004 and 2010 were included. The ROM, HSS score, KS score, WOMAC score, forgotten joint score, OA progression in patellofemoral and lateral compartments, and survivorship were compared within ten years of follow-up between 67 UKA and 67 OWHTO patients after propensity score matching for age, gender, body mass index, range of motion, and osteoarthritis (OA) grade.ResultsAt the last follow-up, there were no significant differences between the two groups in clinical outcomes, but the WOMAC score showed better results after UKA (13.1 in UKA vs 18.9 in OWHTO, P = .011). The OA progression also showed no significant difference between the two groups. After a 10-year follow-up, the survival rate was higher in UKA patients (96.2%) than in OWHTO patients (87.7%), with no statistical difference (P = .06).ConclusionUKA showed better clinical outcomes and OA progressions than OWHTO. The survival rate presented a superiority of 8.5% for the UKA group in the 10-year follow-up, without significant difference.     

The Impact of Coronal Alignment on Revision in Medial Fixed-Bearing Unicompartmental Knee Arthroplasty

BackgroundTo better define the optimal alignment target for medial fixed-bearing unicompartmental knee arthroplasty (UKA), this study compares the postoperative mechanical alignment of well-functioning UKAs against 2 groups of failed UKAs, including revisions for progression of lateral compartment osteoarthritis (“Progression”) and revisions for aseptic loosening or subsidence (“Loosening”).MethodsFrom our prospective institutional database of 3351 medial fixed-bearing UKAs performed since 2000, we identified 37 UKAs revised for Progression and 61 UKAs revised for Loosening. Each of these revision cohorts was matched based on age at surgery, gender, body mass index, and postoperative range of motion with unrevised UKAs that had at least 10 years of follow-up and a Knee Society Score of 70 or greater without subtracting points for alignment (“Success” groups). Postoperative alignment was quantified by the hip-knee-ankle (HKA) angle measured on long-leg alignment radiographs.ResultsThe mean HKA angle at 4-month follow-up for the Progression group was 0.3° ± 3.6° of valgus compared to 4.4° ± 2.6° of varus for the matched Success group (P < 0.001). For the Loosening group, the mean HKA angle was 6.1° ± 3.1° of varus versus 4.0° ± 2.7° of varus for the matched Success group (P < 0.001).ConclusionsPatients with well-functioning UKAs at 10 years exhibited mild varus mechanical alignment of approximately 4°, whereas patients revised for progression of osteoarthritis averaged more valgus and those revised for loosening or subsidence averaged more varus. The optimal mechanical alignment for medial fixed-bearing UKA survival with contemporary polyethylene is likely slight varus.     

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.     

Coronal Alignment of Fixed-Bearing Unicompartmental Knee Arthroplasty Femoral Component May Affect Long-Term Clinical Outcomes

BackgroundThis study aims to investigate the clinical effects of femoral component coronal alignment in a cohort of fixed-bearing unicompartmental knee arthroplasty with clinical and radiological follow-up of 10 years.MethodsProspectively collected registry data of 264 consecutive, cemented, primary fixed-bearing medial unicompartmental knee arthroplasties performed at a single institution from 2004 to 2007 were reviewed. Femoral component coronal angle (FCCA), tibial component coronal angle, and hip-knee-ankle angle were measured on postoperative radiographs. Patients were grouped into acceptable (AG ≤ 3°) and outlier (OG > 3°) groups according to absolute FCCA. Clinical assessment at 6-month, 2-year, and 10-year follow-up was performed using Knee Society Knee and Function Scores, Oxford Knee Score (OKS), and Short Form-36. Fulfillment of expectations, satisfaction, and implant survivorship was recorded.ResultsThere was no significant difference in demographics, tibial component coronal angle, hip-knee-ankle angle, and sagittal parameters in both groups. The OG had poorer OKS at 10 years and a larger deterioration from 2 to 10 years compared to AG (P = .02). Increase in FCCA was associated with deterioration in 2-year OKS (adjusted ß = 0.23, P = .01), 10-year OKS (adjusted ß = 0.26, P = .03), and 2-year Short Form-36 physical component score (adjusted ß = ?0.44, P = .01). Expectation fulfillment at 2 years was lower in the OG vs the AG (88% vs 100%, P = .03). Both groups had similar 10-year survivorship (99% vs 98%, P = .65).ConclusionsFCCA may affect long-term clinical outcomes, but not short-term clinical outcomes nor 10-year survivorship. Given similar limb alignment, coronal and sagittal component positioning, a larger FCCA was associated with poorer outcomes at 10-year follow-up.     

Alignment in Medial Fixed-Bearing Unicompartmental Knee Arthroplasty: The Limb Has a Leg Up on the Component

BackgroundTo assess how implant alignment affects unicompartmental knee arthroplasty (UKA) outcome, we compared tibial component alignment of well-functioning UKAs against 2 groups of failed UKAs, revised for progression of lateral compartment arthritis (“Progression”) and aseptic loosening (“Loosening”).MethodsWe identified 37 revisions for Progression and 61 revisions for Loosening from our prospective institutional database of 3351 medial fixed-bearing UKAs performed since 2000. Revision cohorts were matched on age, gender, body mass index, and postoperative range of motion with “Successful” unrevised UKAs with minimum 10-year follow-up and Knee Society Score ≥70. Tibial component coronal (TCA) and sagittal (TSA) plane alignment was measured on postoperative radiographs. Limb alignment was quantified by hip-knee-ankle (HKA) angle on long-leg radiographs. In addition to directly comparing groups, a multivariate logistic regression examined how limb and component alignments were associated with UKA revision.ResultsIn the Progression group, component alignment was similar to the matched successes (TCA 3.6° ± 3.5° varus vs 5.1° ± 3.5° varus, P = .07; TSA 8.4° ± 4.4° vs 8.8° ± 3.6°, P = .67), whereas HKA angle was significantly more valgus (0.3° ± 3.6° valgus vs 4.4° ± 2.6° varus, P < .001). Loosening group component alignment was also similar to the matched successes (TCA 6.1° ± 3.7° varus vs 5.9° ± 3.1° varus, P = .72; TSA 8.4° ± 4.6° vs 8.1° ± 3.9°, P = .68), and HKA was significantly more varus (6.1° ± 3.1° varus vs 4.0° ± 2.7° varus, P < .001). Using a multivariate logistic regression, HKA angle was the most significant factor associated with revision (P < .001).ConclusionIn this population of revised UKAs and long-term successes, limb alignment was a more important determinant of outcome than tibial component alignment.Level of EvidenceLevel III case-control study.     

混合型单髁与全膝关节置换治疗膝内侧间室骨关节炎的疗效比较

目的：探讨Oxford第3代混合型单髁置换（unicompartmental knee arthroplasty,UKA）与全膝关节置换（total knee arthroplasty,TKA）治疗膝关节内侧间室骨关节炎的疗效。方法：回顾性分析2017年10月至2019年10月行膝关节置换术的156例患者,男44例,女112例,年龄50~75（58.76±4.97）岁。根据不同治疗方式分为单侧TKA组和单侧Oxford第3代混合型UKA组。单侧TKA 81例（81膝）,男23例,女58例,年龄51~75（58.60±5.01）岁;单侧Oxford第3代混合型UKA 75例（75膝）,男21例,女54例,年龄50~72（58.92±4.95）岁。比较两组临床评估指标,包括手术一般情况、相关并发症、美国膝关节协会评分（American Knee Society score,AKSS）临床评分和功能评分;影像评估指标包括髋膝踝角（hip-knee-ankle angle,HKA）、股骨假体内外翻角（femoral component valgus/varus angle,FCVA）、股骨假体后倾角（femoral component posterior slope angle,FCPSA）、胫骨假体内外翻角（tibial component valgus/varus angle,TCVA）、胫骨假体后倾角（tibial component posterior slope angle,TCPSA）,是否发生膝关节外侧间室进展、衬垫脱位、假体下沉、松动。结果：UKA组术中出血量、手术时间、住院天数均显著优于TKA组（P<0.05）,两组术后均未出现并发症。两组患者均获随访,时间24~54（38.01±8.90）个月。末次随访两组AKSS临床评分、功能评分、HKA均优于术前（P<0.05）。末次随访UKA组AKSS临床评分、功能评分均优于TKA组（P<0.05）,TKA组HKA优于UKA组（P<0.05）。末次随访两组TCVA、FCVA差异无统计学意义（P>0.05）,UKA组TCPSA、FCPSA大于TKA组（P<0.05）,UKA组未出现外侧室进展。结论：Oxford第3代混合型UKA治疗膝关节内侧间室骨关节炎,较TKA具有手术创伤小、失血量少、手术时间短、住院时间短、术后快速康复、膝关节功能恢复更好等优势,疗效满意。     

Fixed-Bearing Medial Unicompartmental Knee Arthroplasty in Patients Younger Than 55 Years of Age at 4-19 Years of Follow-Up: A Concise Follow-Up of a Previous Report

BackgroundUnicompartmental knee arthroplasty (UKA) is an effective alternative to total knee arthroplasty (TKA) in isolated unicompartmental disease; however, mid-term to long-term results in young patients are unknown. The purpose of this study is to determine the mid-term outcomes of fixed-bearing medial UKA in patients less than 55 years of age.MethodsSeventy-seven fixed-bearing medial UKAs in patients less than 55 years of age (mean 49.9, range 38-55) from a previously published report were retrospectively reviewed at a mean follow-up of 11.2 years (range 4.1-19.2).ResultsEleven knees were converted to TKA (14.3%) at 0.7-13.8 years postoperatively. The indications for revision included 7 for unexplained pain (9.1%), 2 for grade 4 arthritic progression (1 isolated lateral and 1 lateral and patellofemoral compartments; 2.6%), 1 for polyethylene wear (1.3%), and 1 for femoral component loosening (1.3%). Predicted survivorship free from component revision was 90.4% (95% confidence interval 86.9-93.9) at 10 years and 75.1% (95% confidence interval 66.2-84.0) at 19 years. The mean Knee Society Score improved from a mean of 51.9-88.6 points (P < .001). Of the 52 knees with 4-year minimum radiographs, 3 (5.8%) developed isolated grade 4 patellofemoral arthritis that was asymptomatic, and no knees had evidence of component loosening or osteolysis.ConclusionFixed-bearing medial UKA is a durable option for young patients with unicompartmental arthritis, with good clinical outcomes at mid-term follow-up. Unexplained pain was the most common reason for revision to TKA.     

Differences in Patient-Reported Outcomes Between Unicompartmental and Total Knee Arthroplasties: A Propensity Score-Matched Analysis

Background

The purpose of this study was to compare the patient-reported outcomes regarding joint awareness, function, and satisfaction after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA).

Predicting the Feasibility of Correcting Mechanical Axis in Large Varus Deformities With Unicompartmental Knee Arthroplasty

Background

Due to disappointing historical outcomes of unicompartmental knee arthroplasty (UKA), Kozinn and Scott proposed strict selection criteria, including preoperative varus alignment of ≤15°, to improve the outcomes of UKA. No studies to date, however, have assessed the feasibility of correcting large preoperative varus deformities with UKA surgery. The study goals were therefore to (1) assess to what extent patients with large varus deformities could be corrected and (2) determine radiographic parameters to predict sufficient correction.

Narcotic Consumption in Opioid Naïve Patients Undergoing Unicompartmental and Total Knee Arthroplasty

BackgroundTotal knee arthroplasty (TKA) is associated with increased risk of prolonged narcotic requirement compared to unicompartmental knee arthroplasty (UKA). The purpose of the current study is to compare acute postoperative narcotic consumption between the 2 procedures and quantify narcotic consumption.MethodsFrom October 2017 to August 2019 patients were surveyed for four weeks to determine the amount and duration of opioids consumed and requirement for continued narcotics. Among 976 opioid naïve patients, 314 (32%) underwent UKA and 662 (68%) underwent TKA. Patients were analyzed according to specific narcotic prescribed. Total morphine equivalent dose (MED), number of pills, duration, refill percentage, and usage percentage for 4 weeks were calculated for each procedure.ResultsMED used in the postoperative period was lower in patients undergoing UKA than TKA (200 ± 195 vs 259 ± 250 MED, P = .002). Total number of pills consumed and duration of use was less in UKA compared to TKA regardless of which opioid was prescribed. A smaller proportion of patients required narcotics for 4 weeks after UKA (32% vs 43%, P < .001), and fewer UKA patients required narcotic refills (14% vs 27%, P < .001). Sixty pills of any 1 type of narcotic was sufficient for 90% of UKA patients and over 75% of TKA patients.ConclusionUKA is associated with less narcotic consumption, shorter duration of use, less refills, and lower likelihood of narcotic requirement for 4 weeks. We report narcotic consumption patterns for both procedures to aid surgeons in judicious postoperative prescribing.Level of EvidenceThis is a level III retrospective cohort study reviewing narcotic use in over 900 consecutive opioid naïve patients undergoing UKA or TKA.     

Differences in Pain,Opioid Use,and Function Following Unicompartmental Knee Arthroplasty compared to Total Knee Arthroplasty

BackgroundWe sought to determine if immediate postsurgical pain, opioid use, and clinical function differed between unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA).MethodsA single-institution database was utilized to identify patients who underwent elective total joint arthroplasty between 2016 and 2019.ResultsIn total, 6616 patients were identified: 98.20% TKA (6497) and 1.80% (119) UKA. UKA patients were younger, had lower body mass index, and more often male than the TKA cohort. Aggregate opioid consumption (75.94 morphine milligram equivalents vs 136.5 morphine milligram equivalents; P < .001) along with the first 24-hour and 48-hour usage was significantly less for UKA as compared to TKA. Similarly, pain scores (1.98 vs 2.58; P < .001) were lower for UKA while Activity Measure for Post-Acute Care mobilization scores were higher (21.02 vs 18.76; P < .001). UKA patients were able to be discharged home on the day of surgery 37% of the time as compared to 2.45% of TKA patients (P < .0001). Notably, when comparing UKA and TKA patients who were discharged home on the day of surgery, no differences regarding pain scores, opioid utilization, or mobilization were observed.ConclusionUKA patients are younger, have lower body mass index and American Society of Anesthesiologists scores, and more often male than TKA patients. UKA patients had significantly shorter length of stay than TKA patients and were discharged home more often than TKA patients, on both the day of surgery and following hospital admission. Most notably, UKA patients reported lower pain scores and were found to require 45% lower opioid medication in the immediate postsurgical period than TKA patients. Surprisingly, UKA and TKA patients discharged on the day of surgery did not differ in terms of pain scores, opioid utilization, or mobilization, suggesting that our rapid rehabilitation UKA protocols can be successfully translated to outpatient TKAs with similar outcomes.Level III EvidenceRetrospective Cohort Study.