Unicompartmental Arthroplasty Research Articles

How Useful Is Preoperative Aspiration before Revision of Unicompartmental Knee Prostheses Because of Osteoarthritis in the Other Compartments?

Periprosthetic joint infections (PJIs) of unicompartmental knee arthroplasties (UKAs) can lead to secondary osteoarthritis of the other compartments. The objective of this study was to identify the frequency of PJIs in cases of UKA with progressed secondary osteoarthritis and the result of septic one-stage revision in these cases to verify the value of preoperative aspiration in cases of secondary osteoarthritis of UKA. We retrospectively reviewed 97 patients with a unicompartmental arthroplasty who underwent revision surgery to a total knee arthroplasty (TKA) between January 2013 and March 2021 because of subsequent osteoarthritis. Preoperative aspiration and sample collection during the revision surgery were employed to identify potential periprosthetic joint infections (PJIs). The post-revision period was monitored for septic complications over an average duration of 55.7 ± 25.2 months (24-113). PJIs were identified in 5.2% of cases through preoperative aspiration. In all instances of PJIs, a one-stage septic revision was performed, and notably, none of these cases experienced septic complications during the follow-up period. Preoperative aspiration is essential in order to exclude the presence of a PJI before performing revision surgery of UKA due to secondary osteoarthritis.

Functional improvement of unicompartmental knee arthroplasty compared with total knee arthroplasty for subchondral insufficiency fracture of the knee

Subchondral insufficiency fracture of the knee (SIFK) causes acute knee pain in adults and often requires surgical management. Unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are the two most common surgical treatments for SIFK. While both UKA and TKA have their advantages, there is no consensus for SIFK localized on the medial compartment. We hypothesized that patients with SIFK treated with UKA would show superior patient-reported outcomes compared to those who underwent TKA. A total of 90 patients with SIFK located medially were included in the TKA (n = 45) and UKA (n = 45) groups. Size of SIFK lesions were measured on MR images. Patient reported outcomes in the form of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Hospital Special Surgery (HSS) scores, and Knee Society Scores (KSS) were assessed preoperatively, postoperative 6, 12 months, and at the final follow-up. There were no differences in the size of the SIFK lesion between two groups. At 6 months, WOMAC score was better in the UKA group than the TKA group (p < .01). Both groups had a significant improvement in WOMAC, HSS, and KSS scores at the final follow-up compared to preoperative scores. The UKA group had better range of motion of the knee preoperatively and postoperatively than the TKA group (p < .01 and p < .01). UKA group showed a higher relative risk than the TKA group in terms of complications (RR = 3.0) but with no statistical significance (P = 0.31). Unicompartmental arthroplasty and total joint arthroplasty can produce successful outcomes in patients with SIFK with proper patient selection, regardless of the size of SIFK lesion.

Length of stay and discharge dispositions following robotic arm-assisted total knee arthroplasty and unicompartmental knee arthroplasty versus conventional technique and predictors of delayed discharge.

In-hospital length of stay (LOS) and discharge dispositions following arthroplasty could act as surrogate measures for improvement in patient pathways, and have major cost saving implications for healthcare providers. With the ever-growing adoption of robotic technology in arthroplasty, it is imperative to evaluate its impact on LOS. The objectives of this study were to compare LOS and discharge dispositions following robotic arm-assisted total knee arthroplasty (RO TKA) and unicompartmental arthroplasty (RO UKA) versus conventional technique (CO TKA and UKA). This large-scale, single-institution study included patients of any age undergoing primary TKA (n = 1,375) or UKA (n = 337) for any cause between May 2019 and January 2023. Data extracted included patient demographics, LOS, need for post anaesthesia care unit (PACU) admission, anaesthesia type, readmission within 30 days, and discharge dispositions. Univariate and multivariate logistic regression models were also employed to identify factors and patient characteristics related to delayed discharge. The median LOS in the RO TKA group was 76 hours (interquartile range (IQR) 54 to 104) versus 82.5 (IQR 58 to 127) in the CO TKA group (p < 0.001) and 54 hours (IQR 34 to 77) in the RO UKA versus 58 (IQR 35 to 81) in the CO UKA (p = 0.031). Discharge dispositions were comparable between the two groups. A higher percentage of patients undergoing CO TKA required PACU admission (8% vs 5.2%; p = 0.040). Our study showed that robotic arm assistance was associated with a shorter LOS in patients undergoing primary UKA and TKA, and no difference in the discharge destinations. Our results suggest that robotic arm assistance could be advantageous in partly addressing the upsurge of knee arthroplasty procedures and the concomitant healthcare burden; however, this needs to be corroborated by long-term cost-effectiveness analyses and data from randomized controlled studies.

Robotic-assisted unicompartmental knee arthroplasty: historical perspectives and current innovations.

Robotic assisted unicompartmental knee arthroplasty (RAUKA) has emerged as a successful approach for optimizing implant positioning accuracy, minimizing soft tissue injury, and improving patient-reported outcomes. The application of RAUKA is expected to increase because of its advantages over conventional unicompartmental knee arthroplasty. This review article provides an overview of RAUKA, encompassing the historical development of the procedure, the features of the robotic arm and navigation systems, and the characteristics of contemporary RAUKA. The article also includes a comparison between conventional unicompartmental arthroplasty and RAUKA, as well as a discussion of current challenges and future advancements in the field of RAUKA.

Long-term results of per-operative knee arthroscopy in confirming suitability for unicompartmental arthroplasty

BackgroundPatient selection is key to the success of medial unicondylar knee arthroplasty (UKA). Progression of arthritis is the most common indication for revision surgery. Per-operative arthroscopy is a means of directly assessing the integrity of the lateral compartment. The aim of the study is to assess the long-term survivorship of UKA performed when per-operative arthroscopy is used as a final means of deciding whether to proceed with UKA. MethodsWe used per-operative arthroscopy as a means to confirm suitability for UKA in a consecutive series of 279 Oxford medial UKA. Our series of UKA with per-operative arthroscopy (Group 1) was compared to all Oxford UKA (Group 2) and all UKA in the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) (Group 3). ResultsThe 14-year cumulative percentage revision (CPR) was 18.5% (95% CI 12.7, 26.4) for group 1, 19.7% (95% CI 18.8, 20.6) for group 2, and 19.2% (95% CI 18.5, 19.8) for group 3. There was no statistically significant difference in the (CPR) for the entire period when group 1 was compared to groups 2 or 3. Progression of arthritis was least in Group 1 compared to groups 2 and 3; 3.6 versus 4.4 and 4.1% respectively. Following per-operative arthroscopy 21.6% (77/356) of knees underwent a change of surgical plan from UKA to TKA. ConclusionIn our practice, which includes per-operative arthroscopy, we have identified a reduced risk of revision due to progression of arthritis but no difference in overall long-term implant survivorship.

A new joint reconstruction technique in the treatment of giant cell tumors around the knee: Structural allograft and unicompartmental arthroplasty.

The long-term prognosis of patients who underwent unicompartmental knee arthroplasty (UKA) with a structural allograft or hemiarticular allograft transplantation to treat giant cell tumors (GCTs) around the knee and the prosthesis survival rate were analyzed. We retrospectively reviewed 73 patients who were diagnosed with GCTs around the knee and underwent surgery to restore joint function from 2000 to 2015. Patients were divided into two groups according to the surgical procedure used for functional knee reconstruction: hemiarticular allograft transplantation or structural allograft and UKA. The Knee Society Score (KSS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) were used to analyze postoperative knee function between the two groups. The Kellgren-Lawrence (K-L) classification system was used to evaluate the progression of osteoarthritis. The incidence of complications and the prosthesis survival rate were also investigated. Patients who underwent UKA to treat GCT demonstrated significantly improved knee function. The rate of an excellent or good KSS was significantly different between the two groups (p = 0.041 at the 1-year follow-up, p = 0.033 at the last follow-up). The proportion of severe cases according to WOMAC in the two groups was also different (p = 0.030 at the 1-year follow-up, p = 0.021 at the last follow-up). According to the K-L grade of unaffected compartments, UKA better prevented the progression of osteoarthritis (p = 0.034). Patients with GCTs around the knee could benefit from UKA. In addition to providing better knee function and range of motion, UKA could also slow the progression of osteoarthritis in the knee joint. This new surgical method could meet the needs of patients wishing to preserve joint integrity and favorable joint function.

Lateral meniscus with tears or with histologic calcification does not increase the risk of lateral osteoarthritis after medial unicompartmental arthroplasty.

Meniscal tears or histological meniscal calcifications (in the absence of radiological chondrocalcinosis) are frequent in osteoarthritis. Whether lateral meniscal lesions influence clinical outcomes after medial unicompartmental knee arthroplasty (UKA) is unknown. We analyzed 130 patients (130 knees) with medial unicompartmental knee arthroplasties between 2005 and 2015. These 130 knees had full articular cartilage thickness in the lateral compartment and no radiological chondrocalcinosis on preoperative radiographs. The lateral meniscus was analyzed with preoperative MRI and a biopsy of the anterior horn at the time of surgery. Synovial fluid was collected and analyzed for calcium pyrophosphate dihydrate crystal deposition (CPPD crystals). Lateral meniscal tears were untreated when detected on MRI or during surgery, with the hypothesis that these tears on the opposite compartment would remain asymptomatic in medial UKA. At average 10-year follow-up, patients were evaluated with clinical and radiographic outcome, with a focus on the risk of joint space narrowing of the lateral femorotibial compartment. CPPD crystals were present in the synovial fluid of 70 knees. Lateral meniscal tears were seen on MRI in 34 (49%) normal meniscuses of the 60 knees without CPPD crystals and in six other knees without histological meniscal calcification despite CPPD crystals. Histological calcification was present on 61 lateral meniscuses with 53 meniscal tears. The results showed no significant differences in the clinical outcomes between knees with lateral meniscal tears or lateral meniscal histological chondrocalcinosis or both lesions and those without these conditions. Additionally, radiographic progression of osteoarthritis in the opposite femorotibial compartment of the knee was not more frequent in patients with these meniscal issues. The tenyear cumulative survival rates, measured by the need for total knee arthroplasty, were 91% for knees without meniscal lesions and 92% for knees with these lesions. On this basis, treatment of meniscal tears of the lateral compartment and routine aspiration of the knee to assess for birefringent crystals in the planning of medial UKA do not appear necessary.

Osteotomy versus unicompartmental arthroplasty: an algorithm for anteromedial knee osteoarthritis

Knee arthritis occupies a significant proportion of the musculoskeletal burden in the UK. Total knee arthroplasty currently comprises the mainstay of treatment. There has been a shift towards treating isolated unicompartmental osteoarthritis with bone-preserving surgical techniques, in the form of realignment osteotomy or unicompartmental arthroplasty. There are significant data regarding the survivorship of unicompartmental knee arthroplasty from the National Joint Registry data. Similar registry data are not available for osteotomy surgery yet, but the evidence suggests that unicompartmental knee arthroplasty has greater survivorship. Osteotomies can, however, deliver higher functional return. For both techniques to succeed, it is imperative that rigorous surgical decision-making, with regards to patient selection, should be followed. This paper discusses the basis for these principles and their importance in delivering optimal care. Often, these two surgical techniques are promoted as being mutually exclusive; this paper argues that, in fact, they are part of a complementary algorithm that can deliver the best outcome to the appropriately selected patient.

Comparative Analysis of Unicompartmental Total Knee Arthroplasty and High Tibial Osteotomy: Time to Total Knee Arthroplasty and Other Outcome Measures

There is no consensus on whether unicompartmental arthroplasty (UKA) or high tibial osteotomy (HTO) is superior for unicompartmental arthritis. While there are studies comparing revision and complication rates, none matched a large number of patients undergoing HTO and UKA in the United States and compared these outcomes. We investigated TKA conversion rate and the complications following HTO or UKA. This retrospective study queried the PearlDiver database of all patients undergoing UKA and HTO using CPT codes between January 2011 and January 2020. We compared propensity-matched populations based on age, gender, Charlson comorbidity index, and Elixhauser comorbidity index to compare odds of complications, TKA conversion, and drug use between UKA and HTO groups. Two-independent sample t-test for unequal variances and test of significance were performed. We found 32,583 UKA patients and 816 HTO patients. Each matched group had 535 patients. One-year complication showed higher risk of pneumonia, hematoma, infection, and mechanical complications among HTO patients. UKA patients used narcotics on average of 10.3 days compared to 9.1 days among HTO patients (P < .01). UKA conversion rates were 4.1%, 5.4%, 7.7%, and 9.2% at 1-, 2-, 5-, and 10-year intervals, respectively. HTO conversion rates were less than 2% at 1- and 2-year intervals, 3.4% at 5-year, and 4.5% at 10-year intervals. This difference was statistically significant at 5- and 10-year intervals (P < .01). Using large matched cohorts, HTO may be converted to TKA later than UKA in short- to mid-term follow-up, and HTO patients used opioids for shorter duration.

Radiocapitellar Arthroplasty: Systematic Review.

Primary elbow osteoarthritis affects approximately 2% of the population, and has been treated with arthroplasty. However, total elbow arthroplasty (TEA) implants currently have severe weight limitations and issues with longevity. In patients with unicompartmental arthritis, unicompartmental arthroplasty may be used instead of TEA. We describe the use of Uni-Elbow Radio-Capitellum and Lateral Resurfacing Elbow for radiocapitellar arthroplasty (RCA) in this article. Reviewers independently searched databases for keywords, such as radiocapitellar arthroplasty, RCA, uni-elbow radiocapitellum, UNI-E, and lateral resurfacing elbow, LRE. The measured outcomes of interest were the change in motion arc and patient-reported outcome scores. Studies that were not of appropriate quality determined by the Cochrane risk of bias summary tool and review studies were excluded. RCA resulted in a postoperative 38.3° ± 28.5° increase in elbow flexion-extension (P < .001), and 35.2° ± 28.6° increase in elbow pronation-supination (P < .001). Mayo Elbow Performance Score was significantly increased by 44.8 ± 12.6. DASH Score saw a significant reduction by 45.0 ± 14.6 points (P < .001), while the American Shoulder and Elbow Surgeons Score increased by 47.0 ± 10.6 points (P < .001). Of the 105 adult patients 16.2% experienced complications such as minor stiffness, ulnar neuropathy, component loosening, or radial head UNI-E stem failure. Reported complications were higher in the UNI-E group than in the LRE group. RCA has shown promise as an option to treat radiocapitellar arthritis, particularly when excising the radial head causes lateral column instability.

High early failure rate for a new unicondylar knee system.

This single-center retrospective study evaluated early failure rates for an unicompartmental knee arthroplasty (UKA) system with an anti-allergic surface. We studied 87 consecutive joints received an UKA at a single center between 2017 and 2020. All patients received a fully cemented anti-allergic Univation-Aesculap partial knee replacement implant with a corundum blasting surface. All joints had precise indication of unicompartmental arthroplasty according to the current criteria of this procedure. The current series was restricted to patients undergoing medial cemented UKA. Medial compartment osteoarthritis was the main indication. We found early failure (aseptic loosening) was documented in 20 of the 87 joints (23%). The time to failure ranged from 7 weeks to 3 years, for an estimated 33% (15-46%) cumulative hazard rate for implant loosening over three years. No cases of periprosthetic joint infection were found. On average, the patients began complaining about first symptoms during the third month after surgery. In most cases (66.66%), the cement remained fixed to the bone. Based on these early results, the manufacturer of this implant stopped all further distribution. Continued efforts should be made to understand the clinical and radiographic outcomes of alternative and anti-allergic surface coatings in knee arthroplasty.

Joint Replacement Surgeries Can Be Safely Performed in HIV Patients

Whether joint replacement surgery can be performed safely on HIV patients is still a matter of debate. This study aimed to report the surgical efficacy and complications of joint replacement surgery in HIV patients. A total of 21 HIV patients and 27 non-HIV patients who underwent arthroplasties in our hospital were retrospectively reviewed. The 21 HIV patients received 29 joint replacement surgeries including 27 cases of total hip arthroplasty (THA) and 2 cases of total knee arthroplasty (TKA). The non-HIV patients received 16 THA, 10 TKA, and 3 unicompartmental arthroplasty (UKA). The length of hospital stay of HIV patients was significantly lower than that of non-HIV patients. At the last follow-up, there were no significant complications both in the HIV group and the non-HIV groups. No medical staff had any occupational exposure. We concluded that joint replacement surgery in HIV patients is safe and effective. Optimization of patients is key to treatment success. Strictly following the standardized protection protocol can prevent the risk of occupational exposure.

Presence of a Lateral Trochlear Osteophyte Predicts Medial Unicompartmental Arthroplasty Failure at Midterm Follow-up

BackgroundSpecific clinical and radiographic risk factors for medial unicompartmental knee arthroplasty (UKA) failure are incompletely understood. The purpose of this study was to perform a midterm survivorship analysis of medial UKA from a single, nondesigner surgeon. Based on observations from clinical practice, we hypothesized that the presence of a lateral trochlear osteophyte on preoperative Merchant radiographs may be predictive of medial UKA failure secondary to progressive osteoarthritis (OA). MethodsPatients who underwent a mobile-bearing medial UKA by a single surgeon with minimum 24 months of clinical follow-up from 2008 to 2019 were retrospectively identified. Radiographic parameters, including the presence of a lateral trochlear osteophyte, were measured. Kaplan-Meier survivorship analyses were performed. Cox proportional hazards models were used to evaluate variables as risk factors for UKA failure, defined as reoperation or component revision. ResultsA total of 233 UKAs were included. The mean age was 60 years, mean BMI 32 kg/m2, and 53% of patients were male. The mean follow-up duration was 5.7 years (range, 2.0-13.1 years). Using any reoperation as an endpoint, the 10-year survival was 91%. Using any component revision as an endpoint, the 10-year survival was 93%. Using revision due to progressive OA as an endpoint, the 10-year survival was 95%. The presence of a lateral trochlear osteophyte was associated with an increased risk of any reoperation (hazard ratio 3.6; 95% confidence interval 1.3-9.5) and increased risk of revision due to progressive OA (hazard ratio 9.8; 95% confidence interval 2.9-32.7). ConclusionsThe presence of a lateral trochlear osteophyte on preoperative Merchant view radiographs was associated with an increased risk of medial UKA failure.

A STUDY ON FUNCTIONAL OUTCOME AFTER HIGH FIBULAR OSTEOTOMY IN MEDIAL COMPARTMENT OSTEOARTHRITIS KNEE.

Background: Primary Osteoarthritis of the knee is more prevalent than that of the other joints. Treatment for knee osteoarthritis can be broken down into nonsurgical and surgical management. Initial treatment begins with nonsurgical modalities and moves to surgical treatment once the nonsurgical methods are no longer effective. Various treatment modalities available include intraarticular injections, physiotherapy, visco supplementation, arthroscopic debridement, high tibial osteotomy, and knee replacement with uni compartmental arthroplasty. All of it has its complications. Hence, there is a necessity for a modest technique, easily reproducible, provides decent functional outcomes and associated with a smaller recovery period, and develops the quality of life for the affected patients. In this scenario, this study is designed to know the functional outcomes, when an osteotomy of the bula at proximal 3rd is performed in medial compartment osteoarthritis knee. The present study was conducted at the depart Methods: ment of orthopaedics Andhra medical college/ king George hospital Visakhapatnam between 2019 and 2021.Thirtypatients who fullled inclusion criteria were taken up for study n=30. Statistical Analysis: Statistical analysis was performed using SPSS version 19.0 statistical software for the window. Continuous variables were expressed as mean, ±SD, and dichotomous variables were expressed as percentages. A two-tailed t-test was applied to analyze the postoperative weightbearing ratio of knee joint space (medial/lateral compartment) data. In addition, the nonparametric test (Wilcoxson's signed-rank test) was applied to analyze the OKS, AKSS, and VAS scores. The chi-square test will analyze the Comparison of qualitative variable, and Comparison of the quantitative variable will be analyzed by independent samples unpaired T-test. A P-value less than 0.05 was considered to be signicant. Data will be entered in Microsoft Excel, and data analysis was performed using windows MEDCALC software on a personal computer. Results: Sample size of the present study was 30 (n=30). Average age of the patients was 56 years. with males accounting to 56.66% and female's 43.33 percent. There were 17 males and 13 females among the 30 patients. The majority of the patients have grade 2 medial compartment osteo arthritis. Preoperatively, the mean medial/lateral joint space ratio was 0.26+/-0.12, which increased in the postoperative phase, reaching 0.67+/- 0.29 after six months. Proximal bular osteotomy effectively reduces the pain of m Conclusion: edial compartment osteoarthritis. It also improves the mean vas pain score earliest postoperatively. We observed modest improvement in both oxford knee scores and American knee society score.

Are 20% of Patients Actually Dissatisfied Following Total Knee Arthroplasty? A Systematic Review of the Literature

BackgroundTotal knee arthroplasty (TKA) is among the most performed orthopaedic surgeries in the United States with at least 1,000,000 cases performed per year. Dissatisfaction following TKA has often been reported as 20% or more, with a multitude of causes including sociodemographic, preoperative, and postoperative factors. The purpose of this study was to re-examine the rate and causes of dissatisfaction following TKA. MethodsA systematic review of the literature was performed searching databases from 2010 to 2022. Only primary TKA cases were included and all cases of unicompartmental arthroplasty and revisions were excluded. After abstracts were reviewed, 35 articles were selected for a full-length review, which was ultimately reduced to 21 articles for final inclusion. ResultsThe average rate of patient dissatisfaction was 10%. Excluding complications, the average rate of dissatisfaction was 7.3%. The most common sociodemographic factors for dissatisfaction were age < 65 years, lower income, and non-White patients. Preoperative factors included lower Kellgren-Lawrence scores, depression/anxiety, and pain catastrophizing. Postoperatively, most dissatisfaction was due to complications, unmet expectations, persistent pain, and stiffness. ConclusionBased on our review, the average rate of patient dissatisfaction following TKA is 10%. Improved counseling for known risk factors may have reduced dissatisfaction rates by increasing preoperative patient optimization. Many studies in recent years have demonstrated the issue of poor patient coping skills, such as pain catastrophizing and anxiety/depression as a common cause of dissatisfaction. Ultimately, dissatisfaction following TKA still continues to affect a high portion of patients but less than historical reports of 20%.

CRPS after unicompartmental knee arthroplasty: A case report

A 59-year-old female presented with pain, warmth, erythema, and swelling over the medial aspect of her left knee that began after medial unicompartmental arthroplasty. Exam fulfilled the Budapest criteria for diagnosis of Complex Regional Pain Syndrome (CRPS) type 2. Topical compound cream and physical therapy were prescribed, and symptoms were improved at follow up visit. CRPS localized to the knee after unicompartmental arthroplasty has not been reported in the literature to date, therefore we report a case of CRPS after unicompartmental knee arthroplasty.

Knee arthroplasty utilization trends from 2010 to 2019

BackgroundInterest in partial knee arthroplasty procedures including unicompartmental arthroplasty (UKA), patellofemoral arthroplasty (PFA), and bicompartmental knee arthroplasty (BKA) has increased due to their bone and ligament preservation compared to total knee arthroplasty (TKA). Implant designs, changing thoughts on appropriate indications for partial knee arthroplasty, and availability of navigation also impacted the field over the last decade. The aims of this study were to evaluate trends over the last decade in utilization of 1) partial and total knee arthroplasty; and 2) computer-assistance in knee arthroplasty. MethodsA retrospective cohort analysis was conducted using the PearlDiver database. Patients who underwent PFA, UKA, BKA, and TKA for an indication of osteoarthritis (OA) were identified using Current Procedural Terminology (CPT) codes. Trends analysis from 2010 to 2019 was conducted to compare utilization based on procedure type and computer-assistance. Statistical analysis was conducted using Compounded Annual Growth Rates (CAGR) and linear regression. ResultsFrom 2010 to 2019, there was a significant decrease in utilization of PFA (CAGR: −5.73 %; p = 0.011) and BKA (CAGR: −10.49 %; p = 0.013), but no significant difference in that of UKA (p = 0.224) and TKA (p = 0.421). There was a significant increase in the utilization of computer assistance for both UKA (CAGR: +19.81 %; p = 0.002) and TKA (CAGR: +3.90 %; p = 0.038), but there was no significant difference for computer-assisted PFA (p = 0.724) and BKA (p = 0.951). ConclusionsTKA is still the most common arthroplasty procedure for OA. Decreased utilization of PFA and BKA may be explained by reported failure and revision rates for PFA and BKA compared to TKA.

High Prevalence of Isolated Antero-medial Osteoarthritis (AMOA) in Indian Patients Undergoing Primary Total Knee Arthroplasty.

Isolated antero-medial osteoarthritis (AMOA) of the knee is a distinct pattern of arthritis. Medial arthritis of the knee in select patients can be managed with uni-compartmental arthroplasty (UKA), with studies showing shorter hospital stay, faster rehabilitation and reduced medical complications in the post-operative period compared to TKA. However, the prevalence of AMOA in Indian patients with osteoarthritis of the knee is unknown. The aim of this study was to evaluate the prevalence of AMOA in patients undergoing primary TKA for OA. This was a prospective evaluation of 2518 knees in 1936 patients who were selected for primary TKA. Pre-operative radiographs were screened based on the Oxford UKA Radiological decision aid and diagnosis of AMOA was established. All 2518 knees underwent primary total knee arthroplasty and cases of AMOA were confirmed intra-operatively based on ACL integrity, lateral compartment wear and medial compartment wear pattern. Cases with AMOA arthritic wear pattern were considered amenable for UKA if radiographs showed intact lateral joint space, intra-operatively those with intact and functional ACL, acceptable patellofemoral wear (Outerbridge I-II). We report a prevalence of 46.94% of AMOA, who were amenable for UKA. Obese patients were more likely to have a damaged or non-functional ACL and more likely to have a high degree of wear, not amenable for UKA (p < 0.05). Non-functional ACL was associated with higher prevalence of posterior extension of arthritic wear. This study demonstrated a high prevalence (46.94%) of antero-medial osteoarthritis (AMOA), amenable for UKA. Patient selection is important for improving outcomes after TKA or UKA. Future studies are warranted to compare outcomes of both UKA and TKA in patients with isolated AMOA of the knee.

The learning curve in robotic assisted knee arthroplasty is flattened by the presence of a surgeon experienced with robotic assisted surgery

PurposeThe purpose of this study was to investigate the learning curve associated with robotic assisted knee arthroplasty (RAS KA). Therefore, the evaluation of the influence of an experienced surgeon on the overall team performance of three surgeons regarding the learning curve in RAS KA was investigated. It was hypothesized that the presence of an experienced surgeon flattens the learning curve and that there was no inflection point for the learning curve of the surgical team.MethodsFifty-five cases consisting of 31 total knee arthroplasties (TKA) and 24 unicompartmental arthroplasties (UKA) performed by three surgeons during 2021 were prospectively investigated. Single surgeon and team performance for operation time learning curve and inflection points were investigated using cumulative sum analysis (CUSUM).ResultsA downward trend line for individual surgeons and the team performance regarding the operation time learning curve was observed. No inflexion point was observed for the overall team performance regarding TKA and UKA. The surgeon that performed all cases with the assistance of the experienced surgeon had significantly shorter surgical times than the surgeon that only occasionally received assistance from the experienced surgeon (p = 0.004 TKA; p = 0.002 UKA).ConclusionThe presence of an experienced surgeon in robotically assisted knee arthroplasty can flatten the learning curve of the surgical team formerly unexperienced in robotic assisted systems. Manufacturers should provide expanded support during initial cases in centres without previous experience to robotic assisted knee arthroplasty.Level of evidenceIII.

Distal femoral osteotomy versus lateral unicompartmental arthroplasty for isolated lateral tibiofemoral osteoarthritis with intra-articular and extra-articular deformity: a propensity score-matched analysis

PurposeLateral unicompartmental arthroplasty (UKA) and distal femoral osteotomy (DFO) represent surgical solutions in cases of valgus malalignment and isolated lateral osteoarthritis (OA) of the knee. The aim of the present study was to assess the clinical results, complications, and the overall postoperative alignment of a series of DFO and lateral UKA with a minimum 2-year follow-up in active middle-aged patients.MethodsPatients with valgus knee and isolated lateral OA who underwent opening-wedge DFO or UKA from 2017 to 2019 were reviewed. Each patient was characterized by a joint line convergence angle (JLCA) > 3° and mechanical lateral distal femoral angle (mLDFA) < 87°. We excluded patients who underwent meniscus or osteochondral allograft during DFO. The Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score (KOOS), complications, and postoperative alignment were assessed. Propensity score matching was used to identify comparable patients.ResultsThe DFO and lateral UKA groups consisted of 29 patients each. No statistically significant differences in gender, age, body mass index (BMI), length of follow-up, or limb deformity were reported between the two groups. In the DFO group, OKS was reported to improve from 27.51 to 38.59 (p < 0.05) and KOOS from 51.14 to 67.2 (p < 0.05). Similarly, in the UKA group, OKS improved from 26.23 to 35.43 (p < 0.05) and KOOS from 50.12 to 65.91 (p < 0.05). However, the improvement in OKS and KOOS (delta) did not differ between groups (p = 0.35 and p = 0.95). The DFO and UKA groups were characterized by similar postoperative hip-knee-ankle (HKA) angle measurements of −3.26 and −3.00, respectively (p = 0.65). No patients in the UKA group underwent revision or other knee surgeries during follow-up. No infections were detected in either group. In the DFO group, no cases of nonunion or delayed union were reported. However, 40% of DFO patients underwent plate removal. One patient in each group was characterized by progression of medial OA with Kellgren-Lawrence (KL) grade > 3.ConclusionUKA and DFO represent an effective treatment in lateral knee OA with intra-articular and extra-articular deformity. Both surgeries were able to provide a significant and comparable clinical improvement.Level of evidence: III, comparative retrospective cohort study.