Increased Operative Time Impacts Rates of Short-Term Complications After Unicompartmental Knee Arthroplasty

BackgroundPrevious evidence has demonstrated an exacerbating effect of increased operative time on short-term complications in total joint arthroplasty. While the same relationship may be expected for unicompartmental knee arthroplasty (UKA), supporting evidence remains sparse. The purpose of this study is to determine the impact of operative time on short-term complication rates after UKA and determine a critical threshold in operative times after which complications may increase.MethodsThe American College of Surgeons National Surgical Quality Improvement Project was queried from 2007 to 2018 to identify 11,633 UKA procedures that were included in the final analysis. The effect of operative time on complications within 30 days was evaluated using multivariate logistic regression models. Receiver operating characteristics curves and spline regression models were used to identify critical thresholds in operative time that increase the likelihood of short-term complications.ResultsLonger operative times (in minutes) were associated with higher rates of surgical site infection (90.4 ± 26.7 vs 84.8 ± 25.5, P = .003), blood transfusions (94.9 ± 28.6 vs 84.9 ± 25.5, P = .007), as well as reoperation rates (90.8 ± 27.9 vs 84.9 ± 25.5, P = .01), extended hospital length of stay (93.4 ± 29.8 vs 84.5 ± 25.2, P < .001), and mortality (110.4 ± 35.5 vs 84.9 ± 25.5, P = .008). Following multivariate logistic regression, operative time was found to independently predict increased surgical site infection, blood transfusion, myocardial infarction, extended length of stay, and mortality (odds ratio: 1.09 – 1.45, CI: 1.01 – 1.91, all P values <0.02). Receiver operating characteristics curves found an increase in mortality risk during the 30-day postoperative period after 88.5 minutes of operative time, a finding supported by spline regression plots.ConclusionThe present study found a positive correlation between increased operative times and short-term postoperative complication rates after UKA. Despite a statistically significant association with increasing operative time, odds ratios of reported complications are relatively low.     

Operative Duration and Short-Term Postoperative Complications after Unicompartmental Knee Arthroplasty

BackgroundProlonged operative duration is an independent risk factor for postoperative complications in many orthopedic procedures ranging from shoulder arthroscopy to total hip and knee arthroplasties. It has not been well studied in unicompartmental knee arthroplasty (UKA). The purpose of this study is to assess the effect of operative duration on complications after UKA.MethodsUsing the American College of Surgeons National Surgical Quality Improvement Program registry, we identified all primary unilateral UKAs from 2005 to 18. Patients were divided into three cohorts based on the operative duration: < 90 minutes, between 90 and 120 minutes, and >120 minutes. Baseline patient and operative demographics (age, gender, etc.) and thirty-day complications were compared using bivariate analysis. Multivariate analysis was used to assess the independent effect of operative duration on postoperative outcomes after adjusting for differences in baseline characteristics.ResultsWe identified 11,806 patients who underwent primary UKA from 2005 to 18. There was no difference in the “any complication” rate between cohorts. However, operative duration >120 minutes was associated with a significantly higher likelihood of reoperation (odds ratio [OR] 2.02, 95% confidence interval [CI]: 1.15-3.57, P = .015), non–home discharge (OR: 2.14, CI: 1.65-2.77, P < .001), surgical site infection (OR: 1.76, CI: 1.03-3.01, P = .038), and blood transfusions (OR: 3.23, CI: 1.44-7.22, P = .004) when compared with operative duration <90 minutes. There was no difference in mortality rates.ConclusionIncreased operative duration greater than 2 hours in primary UKA is associated with an increased risk of non–home discharge, surgical site infection, reoperation, and blood transfusion.     

Early Complications After Minimally Invasive Mobile-Bearing Medial Unicompartmental Knee Arthroplasty

The purpose of this article is to review the early complications of minimally invasive mobile-bearing unicompartmental knee arthroplasty by analyzing the first 100 consecutive cases. All cases were medial unicompartmental arthroplasties with a follow-up of at least 24 months (range, 24-51 months). Seven revision procedures were performed due to 2 fractures of the medial tibial plateau, 1 loosening of the femoral component, and 4 dislocations of the meniscal bearing. The early results as determined by The Knee Society scores, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and postoperative range of motion were satisfactory. However, there exists a high rate of early failures, which occurred during the initial learning curve. Therefore, surgeons must be aware that in order to minimize these complications, attention to detail is mandatory.     

Complications of Medial Unicompartmental Knee Arthroplasty

Background

We report intra- and postoperative complications of unicompartmental knee arthroplasty (UKA).

Methods

This study was conducted on 246 cases of UKA which were performed for degenerative osteoarthritis confined to the medial compartment, from May 2002 to May 2010, for which follow-up periods longer than one year were available. Complications were divided into intra- and postoperative complications. Pre- and postoperative clinical scores, the range of motion, and radiologic findings were analyzed.

Results

Complications developed in a total of 24 cases (9.8%, 24/246). Among them, 6 cases had intraoperative complications while 18 had postoperative complications. Among the 6 intraoperative complications, one fracture of the medial tibial condyle, two fractures of the intercondylar eminence, one rupture of the medial collateral ligament, one widening of the peg hole leading to femoral component malposition and late failure, and one total knee arthroplasty (TKA) conversion of a large bony defect of tibial avascular necrosis were observed. Among the 18 postoperative complications, four cases of aseptic loosening of the femoral component, one soft tissue impingement due to malalignment, nine cases of polyethylene bearing dislocation, one case of suprapatellar bursitis, one periprosthetic fracture, one TKA conversion due to medial component overhanging, and one TKA conversion due to pain of unexplained cause were observed.

Conclusions

The mid-term clinical outcomes of UKA were excellent in our study. However, the incidence of complications was very high (9.8%). To prevent intra- and postoperative complications, proper selection of the patients and accurate surgical techniques are required.     

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.     

Robotic-Assisted Versus Manual Unicompartmental Knee Arthroplasty: A Time-Driven Activity-Based Cost Analysis

BackgroundThe cost-effectiveness of robotic-assisted unicompartmental knee arthroplasty (RA-UKA) remains unclear. Time-driven activity-based costing (TDABC) has been shown to accurately reflect true resource utilization. This study aimed to compare true facility costs between RA-UKA and conventional UKA.MethodsWe identified 265 consecutive UKAs (133 RA, 132 conventional) performed at a specialty hospital in 2016-2020. Itemized facility costs were calculated using TDABC. Separate analyses including and excluding implant costs were performed. Multiple regression was performed to determine the independent effect of robotic assistance on facility costs.ResultsDue to longer operative time, RA-UKA patients had higher personnel costs and total facility costs ($2,270 vs $1,854, P < .001). Controlling for demographics and comorbidities, robotic assistance was associated with an increase in personnel costs of $399.25 (95% confidence interval [CI] $343.75-$454.74, P < .001), reduction in supply costs of $55.03 (95% CI $0.56-$109.50, P = .048), and increase in total facility costs of $344.27 (95% CI $265.24-$423.31, P < .001) per case. However, after factoring in implant costs, robotic assistance was associated with a reduction in total facility costs of $235.87 (95% CI $40.88-$430.85, P < .001) per case.ConclusionUsing TDABC, overall facility costs were lower in RA-UKA despite a longer operative time. To facilitate wider adoption of this technology, implant manufacturers may negotiate lower implant costs based on volume commitments when robotic assistance is used. These supply cost savings appear to offset a portion of the increased costs. Nonetheless, further research is needed to determine if RA-UKA can improve clinical outcomes and create value in arthroplasty.     

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).

Cryotherapy Treatment After Unicompartmental and Total Knee Arthroplasty: A Review

Background

Cryotherapy is widely utilized to enhance recovery after knee surgeries. However, the outcome parameters often vary between studies. Therefore, the purpose of this review is to compare (1) no cryotherapy vs cryotherapy; (2) cold pack cryotherapy vs continuous flow device cryotherapy; (3) various protocols of application of these cryotherapy methods; and (4) cost-benefit analysis in patients who had unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA).

Inpatient Versus Outpatient Arthroplasty: A Single-Surgeon,Matched Cohort Analysis of 90-Day Complications

Background

Although some prior work supports the safety of same-day arthroplasty performed in a hospital, concerns remain when these procedures are performed in a free-standing ambulatory surgery center. The purpose of this study is to compare 90-day complication rates between matched cohorts that underwent inpatient vs outpatient arthroplasty at an ambulatory surgery center.

Development of a Machine Learning Algorithm to Predict Nonroutine Discharge Following Unicompartmental Knee Arthroplasty

BackgroundReliable and effective prediction of discharge destination following unicompartmental knee arthroplasty (UKA) can optimize patient outcomes and system expenditure. The purpose of this study is to develop a machine learning algorithm that can predict nonhome discharge in patients undergoing UKA.MethodsA retrospective review of a prospectively collected national surgical outcomes database was performed to identify adult patients who underwent UKA from 2015 to 2019. Nonroutine discharge was defined as discharge to a location other than home. Five machine learning algorithms were developed to predict this outcome. Performance of the algorithms was assessed through discrimination, calibration, and decision curve analysis.ResultsOverall, of the 7275 patients included, 263 (3.6) patients were unable to return home upon discharge following UKA. The factors determined most important for identification of candidates for nonroutine discharge were total hospital length of stay, preoperative hematocrit, body mass index, preoperative sodium, American Society of Anesthesiologists classification, gender, and functional status. The extreme boosted model achieved the best performance based on discrimination (area under the curve = 0.875), calibration, and decision curve analysis. This model was integrated into a web-based open access application able to provide both predictions and explanations.ConclusionThe present model can, following appropriate external validation, be used to augment clinician decision-making in patients undergoing elective UKA. Patients with high preoperative probabilities of nonroutine discharge based on nonmodifiable risk factors should be counseled to start the insurance authorization process with case management to avoid unnecessary inpatient stay, and those with modifiable risk can attempt prehabilitation to optimize these parameters before surgery.     

Robotic-Assisted Unicompartmental Knee Arthroplasty: State-of-the Art and Review of the Literature

Background

Unicompartmental knee arthroplasty is a successful treatment for unicompartmental knee osteoarthritis that has lower complication rates, faster recovery, and a more natural feeling knee compared to total knee arthroplasty. However, long-term survival has been a persistent concern. As more surgeon-controlled variables have been linked to survival, interest in robotic-assisted surgery has continued to grow.

人工单髁膝关节置换术治疗膝骨关节炎

目的探讨人工单髁膝关节置换术治疗单间室膝关节骨关节炎的临床效果。方法2009年1月至2011年12月共收治15例膝关节内侧间室骨关节炎患者,术前关节平均屈曲角度127°（95°～135°）,术前美国纽约特种外科医院膝关节功能评分为48．06分（42～58分）。采用人工单髁膝关节置换术进行治疗,术后早期进行膝关节功能锻炼。结果手术时间75～110min,平均（85±9．89）min;出血量50～300mL,平均（149±45．74）mL。有1例术后7个月出现感染。其余14例均获随访,时间3～30个月。按照美国纽约特种外科医院膝关节评分标准进行疗效评估,优10例,良4例,中0例,差1例,优良率93．3％,膝关节功能评分平均82．8分（42～94分）,膝关节活动范围115°（90°～130°）。末次随访时未发现假体位置不良、假体松动,对侧间室和髌股关节无进行性病变和髌股关节疼痛等并发症。结论在严格适应证的选择下,人工单髁置换术治疗单间室膝关节骨关节炎是创伤小、出血少、效果好的治疗方法。     

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.     

Risk of Periprosthetic Joint Infection After Intra-Articular Corticosteroid Injection Following Unicompartmental Knee Arthroplasty

BackgroundPerioperative intra-articular joint injection is a known risk factor for developing prosthetic joint infection (PJI) in the immediate preoperative and postoperative periods for total knee arthroplasty, but is less defined in unicompartmental knee arthroplasty (UKA). The goal of this study was to elucidate the risk of developing PJI after intra-articular corticosteroid injection (IACI) into a post UKA knee.MethodsA retrospective review of a nationwide administrative claims database was performed from January 2015 to October 2020. Patients who underwent UKA and had an ipsilateral IACI were identified and matched 2:1 to a control group of primary UKA patients who did not receive IACI. Multivariate logistic analyses were conducted to assess differences in PJI rates at 6 months, 1 year, and 2 years.ResultsA total of 47,903 cases were identified, of which 2,656 (5.5%) cases received IACI. The mean time from UKA to IACI was 355 days. The incidence of PJI in the IACI group was 2.7%, compared to 1.3% in the control group. The rate of PJI after IACI was significantly higher than the rate in the control group at 6 months, 1 year, and 2 years (all P < .05). The majority of PJI occurred within the first 6 months following IACI (75%).ConclusionIn this study, IACI in a UKA doubled the risk of PJI compared to patients who did not receive an injection. Surgeons should be aware of this increased risk to aid in their decision-making about injecting into a UKA.Level of EvidenceIII, retrospective comparative study.     

Total Knee Arthroplasty After Failed Unicompartmental Knee Arthroplasty. Clinical Results,Radiologic Findings,and Technical Tips

Background

The loss of anatomic references and bone stock turns unicompartmental knee arthroplasty (UKA) revision surgery difficult, and according to some authors, it is technically as challenging as a total knee arthroplasty (TKA) revision surgery.

Effect of Computer Navigation on Complication Rates Following Unicompartmental Knee Arthroplasty

Background

We evaluated whether the complication and revision rates of unicompartmental knee arthroplasty (UKA) performed with intraoperative computer-based navigation differ from standard UKAs performed without intraoperative computer-based navigation.

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.     

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.