Effect of body mass index on 30-day complication rate and implant survival rate after simultaneous bilateral unicompartmental knee arthroplasty: a multicentre retrospective study.

OBJECTIVE: The practice of simultaneous bilateral unicompartmental knee arthroplasty (SBUKA) remains a topic of debate, particularly in patients with obesity. Thus, the purpose of this study was to assess the impact of body mass index (BMI) on the 30-day complication rate and the survival rate of the implant following SBUKA. METHODS: We retrospectively examined the clinical records of 245 patients (490 knees) who underwent SBUKA at the Affiliated Hospital of Qingdao University and the Third Hospital of Hebei Medical University between January 2010 and December 2020. Patients were categorised based on their BMI at the time of surgery into four groups: normal weight (BMI 18.5 to 22.9 kg/m2), overweight (BMI 23.0 to 24.9 kg/m2), obese (BMI 25.0 to 29.9 kg/m2), and severely obese (BMI ≥30 kg/m2). Variables such as length of hospital stay, duration of surgery, and costs of hospitalisation were compared across all groups. Additionally, we recorded the 30-day postoperative complication rate and the time from surgery to any required revision. The Kaplan-Meier survival analysis was employed to evaluate and compare the implant survival rates. RESULTS: The follow-up period for the 245 patients ranged from 39 to 114 months, with an average of 77.05±18.71 months. The incidence of complications within 30 days post-surgery did not significantly differ across the groups (χ2 = 1.102, p = 0.777). The implant survival rates from the lowest to the highest BMI groups were 97.14%, 93.9%, 94.44%, and 96.43%, respectively. Both the rate of implant revision (χ2 =1.612, p = 0.657) and the survival curves of the implants (p = 0.639) showed no statistically significant differences among the groups. CONCLUSIONS: BMI did not influence the 30-day complication rate nor the survival rate of implants following SBUKA, suggesting that SBUKA should not be contraindicated based on BMI alone.

Challenges in Residual Bearing Removal: A Rare Case of Mobile Bearing Fracture in Unicompartmental Knee Arthroplasty with Literature Review.

BACKGROUND: Mobile bearing fracture is a rare long-term complication of unicompartmental knee arthroplasty (UKA), and relevant reports are sparse. Hence, its treatment options need further exploration. CASE PRESENTATION: This study presents the case of fracture of a polyethylene insert that occurred 12 years after mobile bearing medial UKA in a 75-year-old overweight woman who then underwent surgical intervention at our institution. However, we encountered significant challenges in removing the fragments from the broken bearing, resulting in retention of the remaining one-third of the fragment. We solved this problem by replacing the fractured insert with thicker mobile bearing. During the 1-month postoperative follow-up, the patient achieved good range of motion and excellent satisfaction, with no reported complications and a Knee Society Score of 90. Additionally, we reviewed the literature on the treatment for mobile bearing fractures after UKA. CONCLUSIONS: Bearing fracture is a rare cause of failure of mobile bearing UKA. This case highlights the challenges of UKA fracture bearing retrieval and underscores that mobile bearing replacement can be an effective intervention. The case we report shows that when removal of a residual meniscal bearing in a posterior dislocation is difficult to achieve, compromise may be an appropriate option because it does not cause additional complaints to the patient. This case emphasizes the importance of the surgeon having a thorough preoperative understanding of the location and potential pitfalls of fracture fragments in such situations.

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

PURPOSE: 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. METHODS: 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). RESULTS: 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. CONCLUSION: 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 OF EVIDENCE: 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.

Using orthopaedic health care resources efficiently: A cost analysis of day surgery for unicompartmental knee replacement.

BACKGROUND: Day surgery for unicompartmental knee replacement (UKR) could potentially reduce hospital costs. We aimed to measure the impact of introducing a day surgery UKR pathway on mean length of stay (LOS) and costs for the UK NHS, compared to an accelerated inpatient pathway. Secondly, the study aimed to compare the magnitude of costs using three costing approaches: top-down costing; simple micro-costing; and real-world costing. METHODS: We conducted an observational, before-and-after study of 2,111 UKR patients at one NHS hospital: 1,094 patients followed the day surgery pathway between September 2017 and February 2020; and 1,017 patients followed the accelerated inpatient pathway between September 2013 and February 2016. Top-down costs were estimated using Average NHS Costs. Simple micro-costing used the cost per bed-day. Real-world costs for this centre were estimated by costing actual changes in staffing levels. RESULTS: 532 (48.5%) patients in the day surgery pathway were discharged on the day of surgery compared with 36 (3.5%) patients in the accelerated inpatient pathway. The day surgery pathway reduced the mean LOS by 2.2 (95% CI: 1.81, 2.53) nights and was associated with an 18% decrease in Average NHS Costs (p < 0.001). Mean savings were £1,429 per patient with the Average NHS Costs approach, £905 per patient with the micro-costing approach, and £577 per patient with the "real-world" costing approach. Overall, moving NHS UKR surgeries to a day surgery pathway could save the NHS £8,659,740 per year. CONCLUSION: Day surgery for UKR could produce substantial cost savings for hospitals and the NHS.

Enhancing the Unicompartmental Knee Arthroplasty Safety via Finite Element Analysis of Coronary Plane Alignment: A Case Report.

Although Oxford unicompartmental knee arthroplasty is often used to successfully treat patients with knee osteoarthritis isolated at the medial compartment, we present a case of fracture just below the tibial keel caused by either a shift in medial loading position or an increased amount of tibial osteotomy. Finite element analysis was used to determine which factor was more important. First, a 3D-surface model of the patient's tibia and the implant shape were created using computed tomography-Digital Imaging and Communications in Medicine (CT-DICOM) data taken preoperatively. The finite element analysis found that following unicompartmental knee arthroplasty, the cortical stress (normal, 5.8 MPa) on the medial tibial metaphyseal cortex increased as the load point moved medially (3 and 12 mm medially: 7.0 and 10.7 MPa, respectively) but was mild with increased tibial bone resection (2 and 6 mm lower: 6.1 and 6.5 MPa, respectively). Implanting the femoral component more medially than the preoperative plan increases stresses in the medial cortex of the tibia and may cause fractures.

Reducing edge loading and alignment outliers with image-free robotic-assisted unicompartmental knee arthroplasty: a case controlled study.

BACKGROUND: Survivorship of medial unicompartmental knee arthroplasty (UKA) is technique-dependent. Correct femoral-tibial component positioning associates with improved survivorship. Image-free robotic-assisted unicompartmental knee arthroplasty enables preoperative and intraoperative planning of alignment and assessment of positioning prior to execution. This study aimed to compare the radiological outcomes between robotic-assisted UKA (R-UKA) and conventional UKA (C-UKA). METHODS: This retrospective case control study involved 140 UKA (82 C-UKA and 58 R-UKA) performed at an academic institution between March 2016 to November 2020, with a mean follow-up of 3 years. Postoperative radiographs were evaluated for mechanical axis and femoral-tibial component position. Component position was measured by two methods: (1) femoral-tibial component contact point with reference to four medial-to-lateral quadrants of the tibial tray and (2) femoral-tibial component contact point deviation from the center of the tibial tray as a percentage of the tibial tray width. Baseline demographics and complications were recorded. RESULTS: There was a higher mean component deviation in C-UKA compared with R-UKA using method 2 (17.2% vs. 12.8%; P = 0.007), but no difference in proportion of zonal outliers using method 1 (4 outliers in C-UKA, 5.1% vs. 1 outlier in R-UKA, 1.8%; P = 0.403). R-UKA showed no difference in mean mechanical alignment (C-UKA 5° vs. R-UKA 5°; P = 0.250). 2-year survivorship was 99% for C-UKA and 97% for R-UKA. Mean operative time was 18 min longer for R-UKA (P < 0.001). CONCLUSION: Image-free robotic-assisted UKA had improved component medio-lateral alignment compared with conventional technique.

Clinical Perspectives on Surgical Reconstruction of Eccentric Tumors at the Distal Femur with Unicondylar Resection.

The distal femur is one of the most common sites for primary bone tumors. As the tumor progresses and bone destruction worsens, it can severely affect knee function and even pose a threat to life. In cases where only one condyle is affected and requires resection, preserving the healthy contralateral condyle can substantially enhance the biomechanics of the knee. Furthermore, preserving bone stock may enable future salvage procedures in the event of initial surgery failure, be it from fractures or osteoarthritis. Distal femoral unicondyle resection can offer better functional outcomes in select cases. However, it is essential to prioritize oncological safety with adequate margins over short-term knee function. Currently, the primary methods for reconstruction after the excision of a unicondylar tumor include allograft transplantation (bi- or uni-condylar) and prosthetic or allograft-prosthesis composite replacement (APC). However, there is currently some controversy regarding the optimal surgical reconstruction method, and a consensus within the academic community has yet to be reached. Moreover, due to the rarity of bone tumors, extensive clinical data from a single center is limited. Current studies are mainly retrospective and single-center, lacking sufficient cases and follow-up duration. This article reviews surgical reconstruction after solitary condylar excision in distal femoral tumors. It summarizes, compares, and analyzes mainstream reconstruction methods, exploring their technical details and clinical outcomes to highlight their potential in bone oncology.

Clinical Outcomes and Survivorship of Lateral Unicompartmental Knee Arthroplasty: A Large Single Surgeon Cohort.

BACKGROUND: Lateral unicompartmental knee arthroplasty (UKA) is an effective treatment for isolated lateral compartment osteoarthritis. However, due to the rarity of the procedure, long-term outcomes and survivorship are poorly understood. We report the clinical and radiographic outcomes after lateral UKA. METHODS: We retrospectively reviewed a consecutive series of patients who underwent lateral UKA by a single fellowship-trained arthroplasty surgeon from 2001 to 2021 with a minimum 2 year follow up. There were 161 knees in 153 patients (average age 69 years) that met inclusion criteria, with a mean follow up of 10.0 years (range 0.05 to 22.2). All patients underwent the procedure via a minimally invasive lateral parapatellar approach with a fixed-bearing implant. Patient demographics, complications, radiographic findings, patient-reported outcomes, and the need for revision surgery were evaluated. Survivorship was defined with the end point as revision of components. RESULTS: There were 8 patients (5.0%) who underwent conversion to total knee arthroplasty for lateral UKA implant failure or progression of arthritis. There were 3 patients (1.9%) who underwent ipsilateral medial UKA due to medial compartment arthritis progression with preserved mechanical alignment and patellofemoral joint. There were 8 additional procedures that did not require implant changes, including 5 irrigation and debridements for acute periprosthetic joint infection (3.1%), 2 wound closures for dehiscence (1.3%), and one loose body removal (0.6%). CONCLUSIONS: Lateral UKA showed a survivorship rate of 98.0% at 5 years, 96.0% at 10 years, and 94.5% at 15 years. When including patients who underwent additional surgery for the progression of arthritis, survivorship was 97.4% at 5 years, 95.4% at 10 years, and 91.3% at 15 years. Lateral UKA should be seen as a durable treatment option for isolated lateral compartment osteoarthritis.

Management of Medial Femorotibial Knee Osteoarthritis in Conjunction with Anterior Cruciate Ligament Deficiency: Technical Note and Literature Review.

In recent years, there has been increased interest in the management of medial femorotibial knee osteoarthritis (OA) in conjunction with anterior cruciate ligament (ACL) deficiency. Traditional treatment modalities included conservative therapy, high tibial osteotomy with or without ACL reconstruction, and total knee replacement. Since younger patients with higher physical demands are more likely to suffer from this pathological condition, reduced invasiveness, faster recovery time, and improved knee kinematics are preferred to allow for satisfying clinical and functional outcomes. Thus, a new surgical strategy combining medial unicompartmental knee replacement (UKR) and ACL reconstruction has been proposed to allow bone stock preservation, to reduce surgical morbidity and recovery time, and ultimately to improve joint kinematics and clinical outcomes. Based on the data present in the literature, in the setting of unicompartmental OA in association with ACL deficiency, UKR combined with ACL reconstruction provided encouraging early results. Studies evaluating the outcomes of combined ACL reconstruction and UKR demonstrate promising results in select patient populations. Improved knee stability, pain relief, functional recovery, and patient satisfaction improved after surgery. Moreover, the combined approach offered advantages such as reduced surgical trauma, faster rehabilitation, and preservation of native knee anatomy compared with traditional treatment strategies. However, still, high-level studies on this topic are lacking; therefore, more comparative studies reporting long-term outcomes are needed to support the potential of this combined procedure to become mainstream. In this paper, we discuss the relevant features and rationale behind the indications and technique of this combined surgical procedure, to help surgeons choose the correct therapeutic approach for a patient with concomitant medial OA and ACL insufficiency. Continued advancements in surgical techniques, patient selection criteria, and rehabilitation strategies will further enhance the success of this combined approach, offering hope to individuals with concomitant ACL injuries and unicompartmental knee OA.

Epidemiological Trends and Outcomes of Unicompartmental Knee Arthroplasty Among 104 Million Patients in the United States.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is an alternative to total knee arthroplasty for localized osteoarthritis. Recent advancements in UKA implant design and expanding patient criteria may have increased its utilization. However, few studies have examined the use of UKA in the United States. Thus, this study assessed the current and projected future trends of UKA and robotic UKA in the United States through 2035, along with postoperative outcomes. METHODS: A collaborative healthcare research network was queried to identify patients who had undergone UKA. Primary outcomes measured included prevalence (P), incidence proportion (IP), and incidence rate (IR) from 2012 to 2022. Chi-square analyses were done to compare outcomes across categorical data. Regression modeling was performed to project UKA to the year 2035. Statistical significance was held at P < 0.05 for all analyses. RESULTS: In 2022, 1,662 UKAs were performed within the network, a 590% increase from 2012 (241 performed). The incidence proportion increased on an average annual basis by 41.8%, the incidence rate by 50%, and the prevalence by 51.3%. A year following UKA, conversion to total knee arthroplasty was the most common orthopaedic complication (39.9%). As of 2022, there were 68 robotic UKAs performed, a 518% increase from the 11 performed in 2012. Regression analysis for UKA through 2035 showed that IP will be 0.04%, IR will be 1.75 x 10-6 cases/person-day, and prevalence will be 0.3%. CONCLUSION: These findings are consistent with prior studies indicating a higher utilization of UKA over the past decade. Reported complications were not uncommon, as nearly 40% of patients required a conversion to a total knee arthroplasty. Further research is needed to optimally identify criteria for appropriate patients and determine the benefits robotic UKA may provide, specifically reducing the risk of conversion to a TKA.

Unicompartmental knee arthroplasty combined with posterior cruciate ligament reconstruction: a case report.

BACKGROUND: In this study, we present the unique case of a patient with knee osteoarthritis (OA) of the medial compartment and posterior cruciate ligament (PCL) deficiency who underwent simultaneous medial unicompartmental knee arthroplasty (UKA) and PCL reconstruction. CASE PRESENTATION: A 49-year-old male patient presented with a 1-year history of pain and instability in the left knee. The patient had previously experienced a trauma-related injury to the PCL of the left knee that was left untreated. Imaging and physical examination confirmed the presence of left medial knee OA along with PCL rupture. To address these issues, the patient underwent UKA combined with PCL reconstruction. The patient's Lysholm score was 47 before surgery and 81 three months after surgery, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score was 29 before surgery and 18 three months after surgery, and the International Knee Documentation Committee (IKDC) subjective score was 56.3 before surgery and 74.7 three months after surgery. Six months after surgery, the patient's gait returned to normal, and he was able to jog. CONCLUSION: This case report presents the first instance of UKA combined with PCL reconstruction and introduces a novel treatment approach for patients suffering from medial knee OA and ligament injury.

Metal-backed or all-poly tibial components: which are better for medial unicompartmental knee arthroplasty? A propensity-score-matching retrospective study at the 5-year follow-up.

BACKGROUND: This retrospective medium-term follow-up study compares the outcomes of medial fixed-bearing unicompartmental knee arthroplasty (mUKA) using a cemented metal-backed (MB) or an all-polyethylene (AP) tibial component. MATERIALS AND METHODS: The database of our institution was mined for primary mUKA patients implanted with an MB or an AP tibial component (the MB-UKA and AP-UKA groups, respectively) from 2015 to 2018. We compared patient demographics, patient-reported outcome measures (PROMs), and motion analysis data obtained with the Riablo™ system (CoRehab, Trento, Italy). We conducted propensity-score-matching (PSM) analysis (1:1) using multiple variables. RESULTS: PSM analysis yielded 77 pairs of MB-UKA and AP-UKA patients. At 5 years, the physical component summary (PCS) score was 52.4 ± 8.3 in MB-UKA and 48.2 ± 8.3 in AP-UKA patients (p < 0.001). The Forgotten Joint Score (FJS-12) was 82.9 ± 18.8 in MB-UKAs and 73.4 ± 22.5 in AP-UKAs (p = 0.015). Tibial pain was reported by 7.8% of the MB-UKA and 35.1% of the AP-UKA patients (p < 0.001). Static postural sway was, respectively, 3.9 ± 2.1 cm and 5.4 ± 2.3 (p = 0.0002), and gait symmetry was, respectively, 92.7% ± 3.7 cm and 90.4% ± 5.4 cm (p = 0.006). Patient satisfaction was 9.2 ± 0.8 in the MB-UKA and 8.3 ± 2.0 in the AP-UKA group (p < 0.003). CONCLUSIONS: MB-UKA patients experienced significantly better 5-year static sway and gait symmetry outcomes than AP-UKA patients. Although the PROMs of the two groups overlapped, MB-UKA patients had a lower incidence of tibial pain, better FJS-12 and PCS scores, and were more satisfied.

Trends and outcomes in the surgical management of young adults with knee osteoarthritis using high tibial osteotomy and unicompartmental knee arthroplasty.

INTRODUCTION: A significant portion of knee osteoarthritis is diagnosed in patients under the age of 55, where greater activity demands make total knee arthroplasty less desirable. High tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are useful alternatives, but there is little understanding of which procedure is advantageous. Hence, this study examines the utilization, complication, and reoperation rates among the HTO vs. UKA in young patients with primary osteoarthritis. METHODS: A retrospective review of the National Surgical Quality Improvement Program was performed to identify 2318 patients < 55 years of age who received either a HTO or UKA for primary osteoarthritis between 2011 and 2021. Bivariate analyses compared preoperative and intraoperative characteristics among each procedure. Then, multivariate analyses examined if either procedure was associated with worse 30-day postoperative complications or need for reoperation, independent of the statistically significant pre- and intraoperative disparities. RESULTS: UKAs were performed 14.2 times more commonly than HTOs, and the patients selected for HTO were more likely to be younger, have a lower BMI, have the healthiest ASA Class score, and less likely to have hypertension requiring medication (p < 0.001). HTOs took 17.5% longer to perform and had a longer average length of stay (p < 0.001), while UKAs were more likely to be performed out-patient (p < 0.001). HTOs also had higher rates of serious complications (p = 0.02), overall complications (p = 0.004), and need for reoperation (p = 0.004). Multivariate modelling demonstrated that procedure type was not a predictor of serious complications, but the use of HTO was significantly associated with any complications (odds ratio = 3.63, p = 0.001) and need for reoperation (3.21, p = 0.029). CONCLUSION: Although healthier patients were selected for HTOs, UKAs were found to have a lower risk of complications and immediate reoperation. Additionally, UKAs had the advantage of lower operative burden, shorter length of stay, and a higher efficacy in outpatient settings.

Effect of Topical Application of an NSAID Lateral to the Incision on Postoperative Pain Following Unicompartmental Knee Arthroplasty: A Double-Blind Randomized Controlled Trial.

OBJECTIVE: How to minimize postoperative pain following knee replacement surgery has been a great challenge. This study was performed to evaluate the effect of applying a topical nonsteroidal anti-inflammatory drug (NSAID) lateral to the incision for postoperative pain following unicompartmental knee arthroplasty (UKA). METHODS: The randomized controlled trial enrolled 100 patients from August 2023 to January 2024. One hundred patients who underwent UKA were randomized into two groups. The intervention group received a topical NSAID lateral to the incision postoperatively, and the control group received a placebo lateral to the incision postoperatively. The primary outcome measures were the amount of opioid consumption and the visual analogue scale (VAS) score (12, 24, 36, 48, and 72 h after operation) for pain. The secondary outcome measures were the American Knee Society Score (AKSS, preoperation and 1-month follow-up after operation), the time of first analgesic demand, side effects of opioids, operation time, postoperative stay, surgery-related complications, and postoperative incision healing grade. Independent sample t test and paired sample t test were used to compare continuous data. Chi-square test and Fisher's precision probability tests were used to analyze the categorical data. RESULTS: Ninety-eight patients (intervention group, 48 patients; control group, 50 patients) were analyzed. Opioid consumption was significantly lower in the intervention group than in the control group during the first 12 h, 12 to 24 h, and 24 to 48 h postoperatively (p < 0.05). The VAS score for pain within 72 h postoperatively was significantly lower in the intervention group than in the control group (p < 0.05). There was no significant difference in the AKSS, operation time, postoperative stay, complications, or postoperative incision healing grade between the two groups. The time of first analgesic demand for patient-controlled analgesia was significantly later in the intervention group than in the control group (p < 0.05). There were fewer side effects of opioids in the intervention group (8.3%) than in the control group (18.0%). CONCLUSION: Postoperative application of topical NSAIDs lateral to the incision is an effective and safe method for pain management after UKA, helping to decrease the pain score and reduce opioid consumption postoperatively with no increase in side effects.

Health-related quality of life after total knee arthroplasty and unicompartmental knee arthroplasty for unicompartmental osteoarthritis: A systematic review and meta-analysis.

BACKGROUND: While previous research has demonstrated potential advantages of unicompartmental knee arthroplasty (UKA) over total knee arthroplasty (TKA), particularly in terms of clinical outcomes such as function and pain relief, the specific impact on health-related quality of life (HRQOL) remains unclear. This systematic review and meta-analysis aim to address this gap by comparing HRQOL outcomes between UKA and TKA, providing valuable insights for clinical decision-making. METHODS: We conducted a literature search in the PubMed, Embase, Cochrane Controlled Register of Trials (CENTRAL), and Web of Science databases up to July 15, 2023. Eligible studies assessed HRQOL using EQ-5D, SF-36, or SF-12 and were assessed for methodological quality using the Newcastle-Ottawa Scale (NOS). RESULTS: Seven eligible studies were included, comprising a total of 64,585 patients with 35,809 undergoing TKA and 28,776 undergoing UKA. Patient age ranged from 52.0 to 67.7 years with an average BMI ranging from 27.2 to 31.0 kg/m2. Follow-up periods ranged from 6 months to 10 years. Five studies (63,829 patients) that evaluated HRQOL using EQ-5D showed significantly better outcomes for UKA compared to TKA (MD -0.04, 95% CI -0.05 to -0.02). Two studies (756 patients) that evaluated HRQOL using SF-36 showed no significant difference between TKA and UKA. Five studies (63,286 patients) that evaluated functional outcomes using Oxford Knee Score (OKS) showed significantly better functional scores for UKA compared to TKA (MD -1.29, 95% CI -1.86 to -0.72). Four studies (24,570 patients) that reported patient satisfaction showed no statistically significant difference between TKA and UKA (MD 0.97, 95% CI 0.90 to 1.05). Further subgroup analysis did not affect the conclusions. CONCLUSIONS: Our meta-analysis suggests that UKA is associated with better HRQOL and knee function, as well as similar patient satisfaction, compared to TKA for patients with unicompartmental osteoarthritis.

Long-term functional success and robust implant survival in lateral unicompartmental knee arthroplasty: A case series with a mean follow-up of twenty two and a half years.

PURPOSE: Lateral unicompartmental knee arthroplasty (UKA) is an accepted treatment option in cases of end-stage lateral osteoarthritis. While lateral UKA has many proposed advantages compared to total knee arthroplasty, its technical challenges and relatively small number of cases make this an uncommon procedure. The aim of this study was to report the survivorship and functional outcomes beyond 20 years of follow-up of isolated UKA. METHODS: Between January 1988 and October 2003, 54 lateral UKAs were performed in a single center. The fitted prosthesis was a fixed plate and cemented polyethylene (PE). All patients had isolated lateral tibiofemoral osteoarthritis, including five open meniscectomies, three arthroscopies, and three open reductions of lateral tibial plateau fractures. Patients with a minimum of 20 years of follow-up were included in the final analysis. RESULTS: Of the 54 UKA, 22 died before reaching the minimum follow-up period and four were lost to follow-up. Twenty-eight were included in the final analysis. Among them, 21 patients remained alive and an additional seven were deceased after 20 years. The mean age at the last follow-up was 84.8 ± 11.9 years with a mean follow-up duration of 22.5 ± 2.1 years. Of the 28 knees, eight underwent revision surgery (5 for the progression of osteoarthritis; 2 for aseptic loosening; 1 for PE wear). Kaplan-Meier survival analysis revealed a survival rate at 20 and 25 years of 72.3% (CI 59.1; 88.6). The average time to revision was 14.9 ± 4.9 years. At the last follow-up, the mean function Knee Society Score (KSS) was 41.5 ± 32.9 and the mean objective KSS score was 79.4 ± 9.7. In the unrevised population, 94.7% of patients (n = 18) reported being satisfied or very satisfied with the surgery. CONCLUSION: Lateral UKA remains a viable treatment option for patients with isolated lateral tibiofemoral osteoarthritis, providing satisfactory 20-year implant survivorship and high patient satisfaction.

Unexpected positive cultures in revision total knee arthroplasty after unicompartmental knee arthroplasty.

PURPOSE: Unexpected positive cultures are defined as a single positive culture in intraoperative samples taken during revision surgery after prosthetic joint infection was preoperatively ruled out. This study aims to determine the prevalence of unexpected positive cultures (UPC) in revision total knee arthroplasty (TKA) after unicompartmental knee arthroplasty (UKA). As a secondary objective, this study aims to compare the re-intervention rate in this specific group, between UPC and non-UPC patients. The hypothesis is that the UPC prevalence in patients who undergo a revision TKA after UKA is not higher than in other TKA revision cases and this does not increase the risk of re-intervention. METHODS: This is a retrospective study where all patients who underwent a UKA revision from January 2016 to February 2023 in a high-volume arthroplasty centre, were analyzed. Unexpected positive culture prevalence in this group of patients was obtained. RESULTS: During the included period, 270 UKA revision surgeries were performed. Eight cases had at least two positive cultures and were therefore excluded. The final analysis included 262 patients. Of these, 8 (3.05%) patients presented UPCs and the isolated microorganisms were low-virulence organisms. None of the UPC patients received any treatment. No statistical differences were found between UPC and non-UPC groups in the analyzed variables. CONCLUSION: The prevalence of unexpected positive cultures in patients following revision of unicompartmental knee arthroplasty is lower than in patients who undergo a revision of total knee arthroplasty. In UKA patients a UPC does not seem to increase the risk of a re-intervention, so it can be safely ignored if ICM criteria are not met.

Evaluating the cost of robotic-assisted total and unicompartmental knee arthroplasty.

As uptake of robotic-assisted arthroplasty increases there is a need for economic evaluation of the implementation and ongoing costs associated with robotic surgery. The aims of this study were to describe the in-hospital cost of robotic-assisted total knee arthroplasty (RA-TKA) and robotic-assisted unicompartmental knee arthroplasty (RA-UKA) and determine the influence of patient characteristics and surgical outcomes on cost. This prospective cohort study included adult patients (≥ 18 years) undergoing primary unilateral RA-TKA and RA-UKA, at a tertiary hospital in Sydney between April 2017 and June 2021. Patient characteristics, surgical outcomes, and in-hospital cost variables were extracted from hospital medical records. Differences between outcomes for RA-TKA and RA-UKA were compared using independent sample t-tests. Logistic regression was performed to determine drivers of cost. Of the 308 robotic-assisted procedures, 247 were RA-TKA and 61 were RA-UKA. Surgical time, time in the operating room, and length of stay were significantly shorter in RA-UKA (p < 0.001); whereas RA-TKA patients were older (p = 0.002) and more likely to be discharged to in-patient rehabilitation (p = 0.009). Total in-hospital cost was significantly higher for RA-TKA cases (AU$18580.02 vs $13275.38; p < 0.001). Robotic system and maintenance cost per case was AU$3867.00 for TKA and AU$5008.77 for UKA. Patients born overseas and lower volume robotic surgeons were significantly associated with higher total cost of RA-UKA. Increasing age and male gender were significantly associated with higher total cost of RA-TKA. Total cost was significantly higher for RA-TKA than RA-UKA. Robotic system costs for RA-UKA are inflated by the software cost relative to the volume of cases compared with RA-TKA. Cost is an important consideration when evaluating long term benefits of robotic-assisted knee arthroplasty in future studies to provide evidence for the economic sustainability of this practice.