Unicompartmental Knee Arthroplasty Procedures Research Articles

One-day surgery is safe and effective in unicompartmental knee arthroplasty: A prospective comparative study at 1 year of follow-up.

To compare the outcomes and complications of two perioperative protocols for the management of patients who underwent medial unicompartmental knee arthroplasty (UKA): 24 h (1-day surgery [OS]) versus 72 h (enhanced recovery after surgery [ERAS]) of the length of hospital stay (LOS). In our hypothesis, the reduction of the LOS from 3 to 1 day did not influence the outcomes and complications. A total of 42 patients (21 in each group) with isolated anteromedial knee osteoarthritis and meeting specific criteria were prospectively included in the study. Clinical outcomes included Knee Society Score (KSS) and Forgotten joint score while pain evaluation was performed using a Visual Analogue Scale (VAS). Functional outcomes were assessed measuring the knee range of motion (ROM) while radiographic outcomes were evaluated measuring the amelioration of the varus deformity through the hip-knee-ankle angle (HKA). Clinical and functional outcomes did not significantly differ between the two groups. Complications occurred in 9.5% of OS and 4.7% of ERAS group patients. Significant improvements in knee ROM, VAS pain, KSS and HKA angle were observed postsurgery, with no significant differences between groups except in KSS expectations and function trends. The OS protocol is safe and effective and LOS, in a well-defined fast-track protocol, did not significantly impact clinical and functional outcomes. OS may lead to reduced hospitalisation costs and potential reductions in complications associated with prolonged stays, benefiting both patients and healthcare facilities. However, further research with larger sample sizes and longer follow-up periods is needed to confirm these findings. Early mobilisation and rehabilitation protocols are key components of successful patient recovery following UKA procedures. Level II.

Comparing Complication Rates, Costs, and Length of Stay between Unicompartmental and Total Knee Arthroplasty: Insights from a Big Data Analysis Using the National Inpatient Sample Dataset.

Background: Unicompartmental knee arthroplasty (UKA) is increasingly used for knee osteoarthritis due to faster recovery, better range of motion, and lower costs compared to total knee arthroplasty (TKA). While TKA may offer longer-lasting results with lower revision rates, this study compares the relative benefits and limitations of UKA and TKA using the National Inpatient Sample (NIS) database. Methods: This retrospective analysis examined outcomes of elective UKA and TKA procedures from 2016 to 2019, identifying 2,606,925 patients via ICD-10 codes. Propensity score matching based on demographics, hospital characteristics, and comorbidities resulted in a balanced cohort of 136,890 patients. The present study compared in-hospital mortality, length of stay, postoperative complications, and hospitalization costs. Results: The results showed that UKA procedures increased significantly over the study period. Patients undergoing UKA were generally younger with fewer comorbidities. After matching, both groups had low in-hospital mortality (0.015%). UKA patients had shorter hospital stays (1.53 vs. 2.47 days) and lower costs (USD 55,976 vs. USD 61,513) compared to TKA patients. UKA patients had slightly higher rates of intraoperative fracture and pulmonary edema, while TKA patients had higher risks of blood transfusion, anemia, coronary artery disease, pulmonary embolism, pneumonia, and acute kidney injury. Conclusions: UKA appears to be a less-invasive, cost-effective option for younger patients with localized knee osteoarthritis.

Preserving coronal knee alignment of the knee (CPAK) in unicompartmental knee arthroplasty correlates with superior patient-reported outcomes.

The optimal alignment target for unicompartmental knee arthroplasty (UKA) remains controversial, and literature suggests that its impact on patient-reported outcome measures (PROMs) varies. The purpose of this study was to identify the relationship between changes in the coronal plane alignment of the knee (CPAK) and PROMs in patients who underwent UKA. A retrospective analysis of 164 patients who underwent UKA was conducted. The types of CPAK types categorized into unchanged, minor (shift to an adjacent CPAK type, e.g., type I to II or type I to IV), and major changes (transitioning to a nearby diagonal CPAK type or two types across, such as type I to V or type I to III). PROMs were assessed preoperatively and 1 year postoperatively using the Hospital for Special Surgery (HSS) scores, Knee Society (KS) scores, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Forgotten Joint Scores (FJS). Comparison was performed between patients who experienced and who did not experience any changes in the CPAK. Patients with preserved native CPAK alignment demonstrated significantly superior 1 yearpostoperative outcomes, with higher HSS, KS knee, and WOMAC pain scores (p = 0.042, p = 0.009, and p =0.048, respectively). Meanwhile, the degree of change in CPAK did not significantly influence the PROMs, and patients who experienced minor and major changes in the CPAK showed comparable outcomes. Preserving the native CPAK in UKA procedures is important for achieving favorable clinical outcomes at 1year postoperative. The extent of change in the CPAK type exerted a limited impact on PROMs, thus emphasizing the importance of change in alignment itself.

Patient satisfaction following robotic unicompartmental knee arthroplasty: A systematic review and meta-analysis

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is a viable alternative to total knee arthroplasty (TKA) for osteoarthritis patients with single-compartment involvement, with advantages including accelerated recovery, reduced pain, and improved function. Robotic-assisted UKA (rUKA) is a promising development that ensures precise implant positioning and limb alignment. However, concerns about complications remain. OBJECTIVE: This study looks at patient satisfaction as a key metric for determining the efficacy of rUKA versus manual UKA (mUKA). METHODS: The search strategy for this study followed PRISMA. Using precise keywords, PubMed, Scopus, Web of Science, and the Cochrane library were searched. English articles were searched until August 2, 2023. Selection criteria included mUKA and rUKA patient satisfaction studies. The NOS scale evaluated study quality. Meta-analysis was done with R and heterogeneity analysis. RESULTS: This systematic review examined 5 studies with 1060 UKAs (532 robotic-assisted and 528 manual). Variable satisfaction assessment methods were used. Three studies found no difference in patient satisfaction after robotic-assisted UKA, but two found a higher satisfaction. Meta-analysis showed robotic-assisted UKA improved patient satisfaction (OR = 1.72 [1.25–2.37]). Overall, most studies showed low risk of bias, except one with higher bias. CONCLUSION: This review suggests that robotic assistance may enhance patient satisfaction in UKA procedures.

Unicompartmental knee arthroplasty vs. high tibial osteotomy for medial knee osteoarthritis (UNIKORN): a study protocol of a randomized controlled trial

BackgroundMedial knee osteoarthritis (OA) is a common health problem resulting in knee pain and limiting patients’ physical activity. After failed conservative treatment, unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are possible surgical treatment options for this condition. There is a paucity of high-quality evidence in the literature comparing objective and subjective outcomes of these procedures. Also, there is no common agreement on whether these procedures provide comparable results in late-stage medial knee OA patients.MethodsWe will perform a prospective randomized controlled trial comparing HTO and UKA in patients with late-stage medial knee OA. 100 patients with isolated medial knee OA (KL III–IV) are assigned to either UKA (n = 50) or HTO (n = 50) procedure in patients 45–65 years of age. Our primary outcome will be KOOS5 at one year postoperatively. Secondary outcomes include OARSI physical assessment, length of stay, wearable activity watch, radiographs (OA progression according to Kellgren-Lawrence classification), patient-reported outcomes (KOOS subscales, pain visual analog scale [VAS], Lysholm, and Oxford knee scores), and adverse events (conversion to total knee arthroplasty, surgery-related complications, need for revision surgery) outcomes. Our hypothesis is that neither of the interventions is superior as measured with KOOS5 at 12 months.Ethics and disseminationThe institutional review board of the Helsinki and Uusimaa Hospital District has approved the protocol. We will disseminate the findings through peer-reviewed publications.Trial registrationClinicalTrials.gov/TooloH NCT05442242. Registered on 7/1/2022.

Total knee arthroplasty in France: Male-driven rise in procedures in 2009–2019 and projections for 2050

BackgroundThe number of Total Knee Arthroplasty (TKA) procedures has been rising steadily for several decades in Europe and the USA. The increase varies in pace across countries, with a gradual climb in northern and central Europe, a slowing in the USA, and an exponential surge in the UK. In France, a 32.2% rise in the number of TKA and unicompartmental knee arthroplasty procedures was documented between 2012 and 2018. However, no study has focussed specifically on changes in both TKA procedures and the features of TKA patients. The objective of this study was to use the French national healthcare database to evaluate (1) increases in TKA procedures according to sex and age, (2) whether TKA is being performed at increasingly younger ages, (3) whether the comorbidity profile at TKA is changing, and (4) whether the TKA incidence rate will stabilise in the future, with a projection for 2050. HypothesisIn France, the number of TKA procedures is rising in both males and females but the pace of the increases differs between sexes. Material and methodThis study used data collected in France in 2009–2019, separately for different age groups and for males and females, in the French national healthcare database (Système national des données de santé, SNDS) that collects information on all surgical procedures performed nationwide. Based on information about the TKA procedures, we determined (1) the TKA incidence rates with their time trends and (2) indirectly, the comorbidity profiles of the patients at TKA. Linear, Poisson, and logistic models were built to predict incidence rates in 2030, 2040, and 2050. ResultsBetween 2009 and 2019, the TKA incidence rate showed a steeper increase in males than in females (from 71.2 to 122.9 [+73%] vs. 124.2 to 181.0 [+46%], respectively). Although this increase was replicated in all age groups, it was sharper in patients younger than 65 years, in both males and females (from 20.9 to 37.9 [+82%] and 33.6 to 51.3 [+53%], respectively). During the study period, the number and proportion of patients increased in the group with mild comorbidities (from 40 093 to 67 430 TKAs, i.e., from 53.1% to 65.7% of all TKAs) but not in the other comorbidity groups. All projection models were validated. Nonetheless, the most likely scenario, provided by the logistic model, is a 33% rise by 2050 in both males and females (i.e., to 151 575 TKA procedures) with a plateau starting around 2030. ConclusionAlthough the increase in TKA procedures is more marked in males than in females, the trends are similar in both sexes, with a sharper rise in the group younger than 65 years and a shift toward patients with milder comorbidities. In the longer term, incidence rate trends follow logistic dynamics, with a plateau starting around 2030. To meet the increasing demand, a corresponding development in relevant healthcare resources must be planned. Level of evidenceIV, descriptive epidemiological study.

Does a Uni "Feel Better" than a Total Knee? Not Necessarily, When Using Modern Implant Designs.

Background: When comparing functional outcomes of patients with unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA), studies often report the UKA as the preferred procedure; however, recent improvements in the design of modern TKA implants have aimed at narrowing this gap. Purpose: We sought to compare the "feel" of modern TKA implants to that of UKA, using the Forgotten Joint Score (FJS), a validated patient-reported outcome measure. Methods: We performed a retrospective review of patients who underwent TKA and UKA at 2 institutions between 2014 and 2017. All UKA procedures were robotic arm-assisted with a single implant, "traditional TKAs" were performed using traditional posterior-stabilized implants, and "modern TKAs" were performed using posterior-stabilized implants with a modern design. Differences in FJS were assessed using 1-way analysis of variance and independent 2-sample t tests. Results: A total of 600 patients were included in our study, with 200 patients in each surgical subcategory. Mean age was 62.8 ± 10.2 years and mean body mass index was 29.9 ± 4.9. Modern TKA and UKA had similar FJS at 1 year. While modern TKA had a significantly higher FJS than traditional TKA, UKA did not have a significantly higher FJS than traditional TKA. Conclusion: Our retrospective analysis found no significant differences in the FJS of patients who underwent UKA and TKA with a modern design; however, both had superior scores than traditional TKA designs. This finding suggests that modern TKA designs may have the potential to achieve the natural feeling that is typically associated with joint-conserving surgeries such as UKA, although longer follow-up is necessary.

Effects of Surgeon Handedness on the Outcomes of Unicompartmental Knee Arthroplasty: A Single Center's Experience.

Surgeon handedness has been widely discussed in operative surgery, and could cause clinical discrepancy. However, few studies have reported the effect of handedness on unicompartmental knee arthroplasty (UKA). Based on our clinical observation and case analysis, we aimed to find out the effects of surgeon handedness on UKA. We retrospectively studied 94 UKA procedures performed by one right-handed surgeon from January 2017 to December 2018 at a single medical center. The cases were divided into two groups by operation side (49 L-UKAs and 45 R-UKAs). Preoperative demographic data were collected. Imaging parameters (femorotibial and hip-knee-ankle angles and tibial-plateau retroversion) and joint function scores (Knee Society Score [KSS] and Oxford Knee Score [OKS]) were recorded. Patients were followed up regularly and Forgotten Joint Score (FJS) was calculated at the last follow-up. All data were compared between the two groups with independent-samples t-test, and paired t-test was used for intragroup comparisons. The average follow-up was 26.7 ± 3.2 months. The average patient age was 63.5 ± 9.0 years and the average body mass index was 26.89 ± 3.43 kg/m2 . There was no significant group difference in any preoperative characteristic. Both the KSS and OKS improved significantly after surgery (p < 0.05). No significant group difference was found between the KSS or OKS at any follow-up visit. The varus or valgus of tibial component was 3.57 ± 1.42° on the left side and 3.19 ± 1.56° on the right side (p=0.45). The varus or valgus of femoral component was 7.81 ± 2.43° in patients undergoing L-UKA and 7.05 ± 2.90° in those undergoing R-UKA (p=0.04). No statistical differences were found in outliers of component orientation on both sides. The femorotibial and hip-knee-ankle angles improved significantly in both groups, and there was no significant group difference in either lower limb alignment or tibial-plateau retroversion. The complication rate was 8.16% (4/49) in the L-UKA group and 6.67% (3/45) in the R-UKA group. There was no correlation between prosthesis orientation and early joint function score. Surgeon handedness may cause a worse prosthetic orientation on femoral side during surgeon's non-dominant UKA, and surgeons should be cautious of bone resection and prosthesis implantation. However, radiographic difference did not bring variations on short-term clinical outcomes or lower limb alignment.

High tibial osteotomy with an external fixator or unicompartmental knee arthroplasty for varus knee in young patients?

PurposeThis study compares the functional results and survivorship of unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) with an external fixator for medial compartment osteoarthritis (OA) of the knee. MethodsTwo cohorts of patients aged less than 60 years who had undergone either a cemented medial mobile-bearing UKA or an HTO with an external fixator were included in the study. The first cohort included patients undergoing a series of 197 consecutive medial UKA procedures (UKA group). The second cohort consisted of 60 consecutive patients undergoing HTO with an external fixator (HTO group). Each patient was assessed based on the Oxford Knee Score (OKS), the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Subjective International Knee Documentation Committee (IKDC) score/questionnaire. A clinical evaluation was conducted on the day of the surgery (T0) and at the follow-up visit (T1) (minimum follow-up time was 60 months). Complications and failures resulting from the surgery were recorded for each patient. ResultsOnly the age of the patients at the pre-operative time differed significantly between the two groups, with the HTO group being significantly younger (47.7 ± 8.0 versus 55.8 ± 2.2).After the final follow-up visit, all scores improved in both groups (p < 0.05).IKDC and Oxford scores were higher for the UKA group (p < 0.05). In the HTO group, three complications occurred (5%), including two superficial infections and one deep infection. On the other hand, the UKA group reported four complications (2%): three aseptic mobilisations and one infection requiring revision surgery. There was no difference in the complication rate between the two groups (p = 0.208). ConclusionsIn young patients (<60 years) with an isolated medial knee OA, both HTO and UKA led to good to excellent clinical results with a low rate of complications at mid-term follow-up; both surgical procedures may be considered in this patient population. Level of evidenceLevel III.

Robotic-Arm Assisted Technology’s Impact on Knee Arthroplasty and Associated Healthcare Costs

Background: The number of total knee arthroplasties (TKA) carried out globally is expected to substantially rise in the coming decades. Consequently, focus has been increasing on improving surgical techniques and minimizing expenses. Robotic arm–assisted knee arthroplasty has garnered interest to reduce surgical errors and improve precision. Objectives: Our primary aim was to compare the episode-of-care cost up to 90 days for unicompartmental knee arthroplasty (UKA) and TKA performed before and after the introduction of robotic arm–assisted technology. The secondary aim was to compare the volume of UKA vs TKA. Methods: This was a retrospective study design at a single healthcare system. For the cost analysis, we excluded patients with bilateral knee arthroplasty, body mass index &gt;40, postoperative infection, or noninstitutional health plan insurance. Costs were obtained through an integrated billing system and affiliated institutional insurance company. Results: Knee arthroplasty volume increased 28% after the introduction of robotic-assisted technology. The TKA volume increased by 17%, while the UKA volume increased 190%. Post introduction, 97% of UKA cases used robotic arm–assisted technology. The cost analysis included 178 patients (manual UKA, n = 6; robotic UKA, n = 19; manual TKA, n = 58, robotic TKA, n = 85). Robotic arm–assisted TKA and UKA were less costly in terms of patient room and operating room costs but had higher imaging, recovery room, anesthesia, and supply costs. Overall, the perioperative costs were higher for robotic UKA and TKA. Postoperative costs were lower for robotic arm–assisted surgeries, and patients used less home health and home rehabilitation. Discussion: Surgeons performed higher volumes of UKA, and UKA comprised a greater percentage of total surgical volume after the introduction of this technology. The selective cost analysis indicated robotic arm–assisted technology is less expensive in several cost categories but overall more expensive by up to $550 due to higher cost categories including supplies and recovery room. Conclusions: Our findings show a change in surgeons’ practice to include increased incidence and volume of UKA procedures and highlights several cost-saving categories through the use of robotic arm–assisted technology. Overall, robotic arm–assisted knee arthroplasty cost more than manual techniques at our institution. This analysis will help optimize costs in the future.

Robotic-Arm Assisted Technology's Impact on Knee Arthroplasty and Associated Healthcare Costs.

Background: The number of total knee arthroplasties (TKA) carried out globally is expected to substantially rise in the coming decades. Consequently, focus has been increasing on improving surgical techniques and minimizing expenses. Robotic arm–assisted knee arthroplasty has garnered interest to reduce surgical errors and improve precision.Objectives: Our primary aim was to compare the episode-of-care cost up to 90 days for unicompartmental knee arthroplasty (UKA) and TKA performed before and after the introduction of robotic arm–assisted technology. The secondary aim was to compare the volume of UKA vs TKA.Methods: This was a retrospective study design at a single healthcare system. For the cost analysis, we excluded patients with bilateral knee arthroplasty, body mass index >40, postoperative infection, or noninstitutional health plan insurance. Costs were obtained through an integrated billing system and affiliated institutional insurance company.Results: Knee arthroplasty volume increased 28% after the introduction of robotic-assisted technology. The TKA volume increased by 17%, while the UKA volume increased 190%. Post introduction, 97% of UKA cases used robotic arm–assisted technology. The cost analysis included 178 patients (manual UKA, n = 6; robotic UKA, n = 19; manual TKA, n = 58, robotic TKA, n = 85). Robotic arm–assisted TKA and UKA were less costly in terms of patient room and operating room costs but had higher imaging, recovery room, anesthesia, and supply costs. Overall, the perioperative costs were higher for robotic UKA and TKA. Postoperative costs were lower for robotic arm–assisted surgeries, and patients used less home health and home rehabilitation.Discussion: Surgeons performed higher volumes of UKA, and UKA comprised a greater percentage of total surgical volume after the introduction of this technology. The selective cost analysis indicated robotic arm–assisted technology is less expensive in several cost categories but overall more expensive by up to $550 due to higher cost categories including supplies and recovery room.Conclusions: Our findings show a change in surgeons’ practice to include increased incidence and volume of UKA procedures and highlights several cost-saving categories through the use of robotic arm–assisted technology. Overall, robotic arm–assisted knee arthroplasty cost more than manual techniques at our institution. This analysis will help optimize costs in the future.

Similar clinical and radiographic outcomes after two different hypoallergenic medial unicompartmental knee in patients with metal allergy.

The purpose in the present study was to compare clinical and radiological outcomes of patients who had undergone a mobile-bearing unicompartmental knee arthroplasty (UKA) with either titanium niobium nitride (TiNbN) alloy implants or with fixed-bearing oxidized zirconium alloy implants. The records of two consecutive cohorts for a total of 86 hypoallergenic implants were prospectively analyzed. The first cohort consisted of 49 consecutive implantations of the hypoallergenic UKA Journey Uni Oxinium (Ox Group), while the second consisted of 37 consecutive series of UKA Oxford (TiNbN Group). All patients were evaluated by two independent surgeons who were not involved in the index surgery. The clinical evaluation consisted of evaluating each patient's Oxford Knee Score and Knee Society Score day before surgery (T0), and with two consecutive follow-ups at T1 (minimum follow-up 9months) and T2 (minimum follow-up 24months). The two groups were homogeneous in all preoperative values, except Body Mass Index (BMI) and duration of final follow-up [both statistically higher (p < 0.05) in the TiNbN group]. Both groups showed a clinically significant improvement for all scores at final follow-up (p < 0.05). The only differences between the two groups involved a higher pre-operative Oxford Score in TiNbN group (p = 0.031), and different tibial and femoral angles at the final follow-up. Both TiNbN and Oxinium UKA procedures enabled patients from good to excellent clinical and radiographic outcomes after the final follow-up, regardless of the age, gender, BMI bearing type, and implant size. LEVEL II: Comparative study.

5-Year Survivorship and Outcomes of Robotic-Arm-Assisted Medial Unicompartmental Knee Arthroplasty.

Purpose While unicompartmental knee arthroplasty (UKA) has demonstrated benefits over total knee arthroplasty (TKA) in selected populations, component placement continues to be challenging with conventional surgical instruments, resulting in higher early failure rates. Robotic-arm-assisted UKA (RA-UKA) has shown to be successful in component positioning through preop planning and intraop adjustability. The purpose of this study is to assess the 5-year clinical outcomes of medial RA-UKA. Methods This study was a retrospective review of a single-center prospectively maintained cohort of 133 patients (146 knees) indicated for medial UKA from 2009 to 2013. Perioperative data and 2- and 5-year Knee injury Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Score (WOMAC), and Forgotten Joint Score (FJS) outcome measures were collected. Five-year follow-up was recorded in 119 patients (131 knees). Results Mean follow-up was 5.1 ± 0.2 years. Mean age and BMI were 68.0 ± 8.1 years and 29.3 ± 4.7 kg/m2, respectively. At 2-year follow-up, mean KOOS, WOMAC, and FJS were 71.5 ± 15.3, 14.3 ± 7.9, and 79.1 ± 25.8, respectively. At 5-year follow-up, mean KOOS, WOMAC, and FJS were 71.6 ± 15.2, 14.2 ± 7.9, and 80.9 ± 25.1, respectively. Mean change in KOOS and WOMAC was 34.6 ± 21.4 and 11.0 ± 13.6, respectively (p < 0.001 and p < 0.001). For patient satisfaction at last follow-up, 89% of patients were very satisfied/satisfied and 5% were dissatisfied. For patient activity expectations at last follow-up, 85% met activity expectations, 52% were more active than before, 25% have the same level of activity, 23% were less active than before, and 89% were walking without support. All patients returned to driving after surgery at a mean 15.2 ± 9.4 days. Survivorship was 95% (95% CI 0.91-0.98) at 5 years. One knee (1%) had a patellofemoral revision, two knees (1.3%) were revised to different partial knee replacements, and five knees (3.4%) were converted to TKA. Conclusion Overall, medial RA-UKA demonstrated improved patient-recorded outcomes, high patient satisfaction, met expectations, and excellent functional recovery. Midterm survivorship was excellent. Longitudinal follow-up is needed to evaluate long-term outcomes of robotic-arm-assisted UKA procedures.

Early Outcome Trends of Unicompartmental Knee Arthroplasty in Patients With Morbid Obesity: A Potential for Outpatient Surgery

BackgroundElevated body mass index (BMI) was previously considered a contraindication to unicompartmental knee arthroplasty (UKA). This study sought to determine if outcomes following UKA in patients with elevated BMI have improved over the years. We hypothesized that operative times and length of stay (LOS) following UKA would significantly decrease, while discharge to home rates would increase across all BMI cohorts, especially those with a BMI > 40. MethodsUsing the National Surgical Quality Improvement Program registry, surgical cases categorized using the Current Procedural Terminology code 27446 for UKA with a recorded height and weight were included. Three BMI cohorts were created: BMI I (BMI < 30), BMI II (30 ≤ BMI ≤ 40), and BMI III (BMI > 40). Each BMI group was subclassified temporally by year of operation: Years A (2006-2009), Years B (2010-2014), and Years C (2015-2019). ResultsA total of 14,114 patients were included. For BMI III, both operative time (P < .001) and LOS (P < .001) significantly decreased over the Years cohorts. Discharge home rates increased from 88.3% to 94.4% in BMI III (P = .001). All BMI cohorts saw similar changes in discharge patterns, 30-day readmissions, and reoperations within 30 days in recent years. ConclusionThis study found that operative times and LOS have decreased significantly in patients with morbid obesity over the past 14 years, while more patients are being discharged home without being readmitted or reoperated on in the first month. As surgeons continue to improve their operative and reconstructive techniques, this study suggests that patients with elevated BMI should be considered candidates to undergo UKA procedures in ambulatory surgery centers or in hospitals with a rapid recovery unit.

Unicompartmental Knee Arthroplasty Utilization among Early Career Surgeons: An Evaluation of the American Board of Orthopaedic Surgery Part-II Database.

An updated understanding of unicompartmental knee arthroplasty (UKA) utilization is needed. The purpose of this study was to evaluate temporal trends in volume and utilization of UKA among early-career surgeons and to examine the influence of fellowship training status on utilization of UKA. The American Board of Orthopaedic Surgery (ABOS) Part-II database was queried from 2010 to 2019 to identify candidates who reported ≥1 total knee arthroplasty (TKA) or UKA. Self-reported history of fellowship training experiences was recorded. "High-volume" surgeons were defined as performing ≥7 UKA over the ABOS Part-II collection period. Trends were evaluated with the Cochrane-Armitage test and generalized linear models. From 2010 to 2019, a total of 2,045 candidates (28.1%) reported ≥1 TKA, while 585 candidates (8.0%) reported ≥1 UKA. The number of candidates reporting ≥1 UKA significantly increased (p = 0.001). An increase in UKA volume was observed over the study period (p < 0.001). Rates of utilization of UKA relative to TKA did not change significantly over the study period (p = 0.11). Sixty-three (2.4%) candidates met the study definition for high-volume UKA utilization. UKA procedure volume increased among ABOS Part-II candidates over the study period; however, rates of UKA utilization relative to TKA volume remained unchanged. Increasing volume of UKA performed by early-career surgeons is likely secondary to an increased number of surgeons trained in adult reconstruction. Only 2.4% of candidates who reported performing at least one knee arthroplasty procedure met the threshold for a high-volume UKA practice. Early-career surgeons should remain conscientious of UKA volume in their practice.

The Renaissance of Unicompartmental Knee Arthroplasty appears rational - A radiograph-based comparative Study on adverse Events and patient-reported Outcomes in 353 TKAs and 98 UKAs.

PurposeTotal knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) are both considered suitable for antero-medial osteoarthritis and spontaneous osteonecrosis of the knee. National registry data are consistent in showing higher revision rates for UKA. Adequately adjusted, these findings may be challenged by differences in adverse events and patient-reported outcomes, as both can have serious long-term implications. Based on preoperative radiographs, the aim was to retrospectively compare the two principle surgeries in these respects.MethodsAll TKA procedures in 2016 in one Swedish county council were, according to certain radiograph-based consensus criteria, visually evaluated for medial UKA suitability. Then, using different regression models, they were compared with the corresponding medial UKAs performed in 2015–2017 regarding complications and patient-reported outcomes one year after surgery.ResultsThe UKA group showed an 82% reduced risk (OR 0.2; 95% CI 0.0–0.6) of any complications, whereas the 55% reduced risk of severe complication did not reach statistical significance (OR 0.5; 95% CI 0.1–2.1). These findings corresponded in high-volume surgeries to an absolute complication rate of 0% in the UKA group and 10% in the TKA group (p = 0.005) and to a severe complication rate of 0% and 5% respectively (p = 0.05). Though no differences were seen in any general patient-reported outcomes, the pain and function based OMERACT-OARSI responder criteria indicated in both around a 60% better chance of any response (OR 1.6 CI % 0.6–4.5) and a high response (OR 1.6; 95% CI 0.7–3.4) in the UKA group.ConclusionNo differences were shown in patient-reported outcomes but a clear difference in risk of complications, favoring the UKA procedure.

Unicompartmental Knee Arthroplasty Is Not Associated With Increased Revision Rates in Obese Patients.

BackgroundThere is controversy among arthroplasty surgeons in regard to performing unicompartmental knee arthroplasty (UKA) in obese patients based on current literature. The aim of this study is to investigate whether UKA is associated with increased complications and revision rates in obese (body mass index [BMI] > 30 kg/m2), morbidly obese (BMI > 40 kg/m2), and super morbid obese (BMI > 50 kg/m2) patients.MethodsWe retrospectively reviewed all UKAs performed at our institution from January 2008 to December 2017. A total of 2178 UKA procedures were performed during this period. The patients were categorized based on BMI to include normal weight (BMI = 20-30 kg/m2), obese (BMI ≥ 30.1-40 kg/m2), morbidly obese (BMI ≥ 40.1-50 kg/m2), and super morbid obese (BMI ≥ 50.1 kg/m2) groups. Record review was performed to obtain demographic data, need for revision (timing, type, and etiology), and complication rate and cause.ResultsThe 2178 UKA cases were eligible for inclusion in this investigation. We performed 2028 medial UKAs and 150 lateral UKAs. The mean clinical follow-up period was 3.7 years, and the mean time from index surgery to revision was 7.2 years. Of the 2178 UKA cases, 1167 had a 3-year minimum follow-up. The overall revision rate in all patients was 2.2%. There was no significant difference (P > .05) in revision rates among normal weight (3.0%), obese (2.7%), morbidly obese (1.9%), and super morbid obese patients (1.8%). Most failures in all groups were secondary to progression of osteoarthritis requiring total knee arthroplasty.ConclusionsSimilar rates of revision were found for UKAs performed on obese, morbidly obese, or super morbid obese patients (≤2.0% revision rate) vs normal BMI (2.7% revision rate) patients. Progressive osteoarthritis was the most common mechanism of UKA failure. Obesity is not a contraindication for UKA despite previous recommendations to the contrary.

Incidence, temporal trends and potential risk factors for aseptic loosening following primary unicompartmental knee arthroplasty: A meta-analysis of 96,294 knees

BackgroundAseptic loosening (AL) is among the major reasons for revision of failed primary unicompartmental knee arthroplasty (UKA). There is an ongoing temporal increase in the use of UKA with a resultant increase in the revision burden. We aimed to evaluate the incidence of, temporal trends and risk factors for AL. MethodsLongitudinal studies reporting the incidence of AL following primary UKA were sought from MEDLINE, Embase, Web of Science and Cochrane Library up to 6th April 2020. Incidence and relative risks (RR) (with 95% confidence intervals) were calculated. ResultsWe identified 62 studies for inclusion. Overall, 96,294 primary UKA procedures accounting for 1752 AL cases were included. AL incidence ranged from 0.00% to 22.70% over a 7.7 year weighted mean follow-up. The pooled random effects incidence (95% CI) was 1.77% (1.34–2.25) in the same follow-up period. The annual rate of AL was 0.10% (0.02–0.22). AL incidence increased with length of follow-up, but there was a temporal decrease from the 1970s onwards. Tibial loosening was more common than femoral component loosening: incidence (95% CI) of 1.63% (0.96–2.44) and 0.58% (0.20–1.09) respectively over a weighted follow-up of 6.6 years. Fixed bearing implant design and cemented fixation were both associated with increased AL risk, whereas robotic-assisted surgery was associated with decreased risk. ConclusionThe overall incidence of AL following primary UKA is primarily driven by tibial component loosening and there is a temporal decline in rates. The use of mobile bearing, uncemented implants inserted with robotic assisted surgery may reduce the risk of AL.

Résultats décevants entre les performances fonctionnelles et la satisfaction des patients ayant une prothèse unicompartimentale du genou: une étude transversale

BackgroundFollowing a Unicompartmental knee arthroplasty (UKA) satisfaction is often conflated with functional outcome. Recent studies have shown that satisfaction is not linked to functional outcome. The research questions were: (1) what is the relationship between satisfaction and functional performance and quality of life (absolute and gain values) after UKA? And (2) what is the level of satisfaction, function, and quality of life after UKA? HypothesisThere is a poor relationship between functional performance and patient satisfaction following UKA. MethodsThis was a retrospective study using a locally held arthroplasty register to identify patients who had undergone UKA between 2004 and 2017. Patient reported outcome measures (PROMs) were collected prospectively and included EQ-5D, Oxford Knee Score (OKS) and satisfaction score (based on a visual analogue score with 0 being worst and 100 being best). Patients with a complete set of pre-operative and 2-year post-operative outcome scores were included. Patients who subsequently underwent revision surgery were excluded. 1638 patients were identified, of which 896 were eligible for inclusion. The average age was 66.7 years old, with 46.3% of patients being female. ResultsThere was a moderate to strong correlation between the absolute or relative values for OKS and the patient satisfaction following UKA (r=0.705 and r=0.522, respectively). The average pre-operative scores improved from a median of 23 (IQR 18–28) to 43 (IQR 35–46) (p<0.001) and from a median of 0.62 (IQR 0.186–0.691) to 0.85 (IQR 0.691 – 1) (p<0.001) for OKS and EQ-5D, respectively. In terms of satisfaction with outcome, 82.6% of patients were very satisfied and 4.4% were dissatisfied (scoring ≥80% and <50%, respectively). At 2 years, the PASS was met or surpassed by 73.1% and 54.9% (OKS and EQ-5D, respectively). The MCID was met or surpassed by 93% and 78% (OKS and EQ-5D, respectively). Discussion/ConclusionUKA is a successful procedure generating high levels of patient function and satisfaction. Because patients’ OKS and EQ-5D scores may be influenced by comorbidities, those scores are of disappointing predictive value in estimating patient satisfaction, and therefore should not be used as a surrogate to determine the success of the UKA procedure. Level of EvidenceIII, Restrospective cohort study.

The current status of daycase hip and knee arthroplasty within the English National Health Service: a retrospective analysis of hospital episode statistics data.

A high volume of total hip, total knee and unicompartmental knee arthroplasty procedures, an ageing population and continuing financial pressures within the English NHS mean that strategies to reduce length of hospital stay are attractive. Enhanced recovery after surgery protocols are one such intervention, and have advanced so that daycase arthroplasty is now possible. This study examines the current rate of daycase arthroplasty within the English NHS. Hospital episode statistics data from all English NHS providers of arthroplasty procedures were analysed. Activity, daycase rate, length of stay and readmission rates were recorded. All total hip, knee and unicompartmental knee operations undertaken within the time period 1 July 2018 to 30 June 2019 were examined. Length of stay was analysed for 162,966 patients; 74,665 (46%) were total hip arthroplasty, 79,252 (49%) were total knee arthroplasty and 9,049 were unicompartmental knee arthroplasty (5%). Mean length of stay was 4.08 days for total hip, 4.11 days for total knee and 2.64 days for unicompartmental knee arthroplasties. Daycase rate for total hip arthroplasty was 0.55%, 0.52% for total knee arthroplasty and 5.44% for unicompartmental knee arthroplasty. The percentage of patients staying in hospital for longer than four days (a length of stay of five days or more) was 18.61% of total hip arthroplasty spells, 20.54% of total knee arthroplasty spells and 5.48% of unicompartmental knee arthroplasty spells. This large observational study of unselected patients undergoing hip and knee arthroplasty demonstrates that the national daycase rate for arthroplasty across providers in the NHS is low. Mean length of stay remains higher than selected international comparators.