Unicondylar Knee Arthroplasty Research Articles

Clinical efficacy of intraarticular vancomycin in preventing early periprosthetic joint infection after primary knee arthroplasty

Objective: To investigate the clinical effect of intraarticular vancomycin on early periprosthetic joint infection (PJI) in knee arthroplasty and the incidence of postoperative complications. Methods: This is a retrospective cohort study. The clinical data of 1 867 patients who underwent primary knee arthroplasty at Department of Joint Surgery, the Affiliated Hospital of Qingdao University from April 2022 to June 2023 were retrospectively analysed, including total knee arthroplasty (TKA), robotic-assisted total knee arthroplasty (RA-TKA) and unicondylar knee arthroplasty (UKA). There were 687 males and 1180 females, aged (68.0±11.2)years(range:45 to 87 years). Patients were divided into the vancomycin group and the control group according to whether or not intra-articular injection of 1 g of vancomycin powder dissolved in 30 ml of saline was performed after intraoperative joint capsule closure. In the vancomycin group, 925 patients were included, including 782 TKA, 27 RA-TKA and 116 UKA.In the control group, 942 patients were included, including 767 TKA, 99 RA-TKA and 76 UKA. Early PJI, wound complications, and vancomycin-related toxicity including acute renal collapse, ototoxicity, and allergic reactions were assessed within 3 months postoperatively. Results: No PJI was found in all patients in the vancomycin group.Five cases (0.7%,5/767) of early PJI were found in TKA patients in the control group, with a statistically significant difference (P=0.030); 1 case of early PJI was found in each RA-TKA and UKA patients, with non-significant difference compared with vancomycin group (all P>0.05). Two cases (0.3%,2/782) of incisional complications were found in TKA patients in the vancomycin group, and 4 cases (0.5%, 4/767) of incisional complications were found in TKA patients in the control group, with non-significant difference(P=0.449); no incisional complications were found in RA-TKA patients in the vancomycin group, and 1 case (1.0%,1/99) of incisional complications were found in RA-TKA patients in the control group, the difference was not statistically significant (P>0.05); no incisional complications were found in both groups of UKA patients.No vancomycin-related acute kidney injury, ototoxicity, or allergic reactions was observed in all patients. Conclusion: Intra-articular injection of 1 g of vancomycin suspension after arthrotomy closure during TKA maybe lower the risk of early PJI without increasing the risk of wound complication and vancomycin-associated systemic toxicity.

Unicondylar knee arthroplasty demonstrating a significant increased risk for aseptic revisions compared to unconstrained and constrained total knee arthroplasty: An analysis of aseptic revisions after unicondylar and primary total knee arthroplasty of the German Arthroplasty Registry.

Due to ageing population, the implantation rate of total knee arthroplasties (TKAs) is continuously growing. Aseptic revisions in primary knee arthroplasty are a major cause of revision. The aim of the following study was to determinate the incidence and reasons of aseptic revisions in constrained and unconstrained TKA, as well as in unicondylar knee arthroplasties (UKAs). Data collection was performed using the German Arthroplasty Registry. Reasons for aseptic revisions were calculated. Incidence and comparison of aseptic revisions were analysed using Kaplan-Meier estimates. A multiple χ2 test with Holm's method was used to detect group differences in ligament ruptures. Overall, 300,998 cases of knee arthroplasty with 254,144 (84.4%) unconstrained TKA, 9993 (3.3%) constrained TKA and 36,861 (12.3%) UKA were analysed. Aseptic revision rate in UKA was significantly increased compared to unconstrained and constrained TKA (p < 0.0001). In constrained TKA, a 2.0% revision rate for aseptic reasons were reported after 1 year, while in unconstrained TKA 1.1% and in UKA, 2.7% of revisions were identified. After 7 years in constrained TKA 3.3%, in unconstrained TKA 2.8%, and in UKA 7.8% sustained aseptic revision. Ligament instability was the leading cause of aseptic revision accounting for 13.7% in unconstrained TKA. In constrained TKA, 2.8% resulted in a revision due to ligament instability. In the UKA, the most frequent cause of revisions was tibial loosening, accounting for 14.6% of cases, while progression of osteoarthritis accounted for 7.9% of revisions. Ligament instability was observed in 14.1% of males compared to 15.9% of females in unconstrained TKA and in 4.6% in both genders in UKA. In patients with UKA, aseptic revision rates are significantly higher compared to unconstrained and constrained TKA. Ligament instability was the leading cause of aseptic revision in unconstrained TKA. In UKA, the most frequent cause of revisions was tibial loosening, while progression of osteoarthritis was the second most frequent cause of revisions. Comparable levels of ligament instability were observed in both sexes. Level III, cohort study.

Load transfer in bone after partial, multi-compartmental, and total knee arthroplasty.

Introduction: Arthroplasty-associated bone loss remains a clinical problem: stiff metallic implants disrupt load transfer to bone and, hence, its remodeling stimulus. The aim of this research was to analyze how load transfer to bone is affected by different forms of knee arthroplasty: isolated partial knee arthroplasty (PKA), compartmental arthroplasty [combined partial knee arthroplasty (CPKA), two or more PKAs in the same knee], and total knee arthroplasty (TKA). Methods: An experimentally validated subject-specific finite element model was analyzed native and with medial unicondylar, lateral unicondylar, patellofemoral, bi-unicondylar, medial bicompartmental, lateral bicompartmental, tricompartmental, and total knee arthroplasty. Three load cases were simulated for each: gait, stair ascent, and sit-to-stand. Strain shielding and overstraining were calculated from the differences between the native and implanted states. Results: For gait, the TKA femoral component led to mean strain shielding (30%) more than three times higher than that of PKA (4%-7%) and CPKA (5%-8%). Overstraining was predicted in the proximal tibia (TKA 21%; PKA/CPKA 0%-6%). The variance in the distribution for TKA was an order of magnitude greater than for PKA/CPKA, indicating less physiological load transfer. Only the TKA-implanted femur was sensitive to the load case: for stair ascent and gait, almost the entire distal femur was strain-shielded, whereas during sit-to-stand, the posterior femoral condyles were overstrained. Discussion: TKA requires more bone resection than PKA and CPKA. These finite element analyses suggest that a longer-term benefit for bone is probable as partial and multi-compartmental knee procedures lead to more natural load transfer compared to TKA. High-flexion activity following TKA may be protective of posterior condyle bone resorption, which may help explain why bone loss affects some patients more than others. The male and female bone models used for this research are provided open access to facilitate future research elsewhere.

Unicondylar knee arthroplasty-trigger for outpatient arthroplasty

The combination of areduction in surgical trauma in unicondylar knee arthroplasty compared to total knee arthroplasty and the introduction of astandardised enhanced recovery concept leads to apre-, peri- and postoperative improvement in the patient's condition, which results in areduction of the length of stay in hospital. In healthy, motivated patients, day-case or outpatient surgical treatment is possible under these circumstances.

Effects of high tibial osteotomy compared with unicondylar knee arthroplasty on the surgical site wound infection and pain in patients with medial knee osteoarthritis.

This study aims to comprehensively compare the effects of unicondylar knee arthroplasty (UKA) and high tibial osteotomy (HTO) on wound infection and pain in patients with medial knee osteoarthritis. A computerized search was conducted in Embase, PubMed, Google Scholar, China National Knowledge Infrastructure, Cochrane Library and Wanfang databases, from database inception to October 2023, for studies comparing UKA and HTO for medial knee osteoarthritis. Studies selection, data extraction and study quality evaluation were independently conducted by two researchers. Stata 17.0 software was employed for data analysis. Overall, 10 studies involving 870 patients with medial knee osteoarthritis were included. It was found that the UKA group had significantly lower wound visual analogue scale scores compared to the HTO group (SMD = -0.53, 95%CI: -0.87 to -0.20, p < 0.001). The incidence of wound infection in the UKA group was higher than in the HTO group (OR = 1.92, 95%CI: 0.65-5.69, p = 0.240), and the incidence of complications was lower (OR = 0.89, 95%CI: 0.52-1.54, p = 0.684), though these differences were not statistically significant. This study indicates that UKA is effective in alleviating postoperative wound pain in medial knee osteoarthritis. However, the rates of postoperative wound infection and complications are comparable to those of HTO. Clinicians should consider factors such as patient age and disease severity in making individualized treatment decisions.

A preliminary study on analysis of lower limb energy during walking in the patients with knee replacement

BackgroundKnee replacement surgeries are used to reduce pain and enhance functionality for individuals with knee arthritis. It is predicted that the annual volume of total knee replacement surgeries conducted in the US will surge by a substantial 673% by 2030. Though a lot of studies have done gait analysis on patients with knee replacement, little research is on energy changes in the lower limbs during gait. This study aimed to investigate the mechanical energy changes in the lower limbs for patients with total knee arthroplasty (TKA) and unicondylar knee arthroplasty (UKA), and ultimately to provide a specific tool to analyze limb energy during gait in clinical practice. Methods10 TKA and 8 UKA patients were recruited for gait analysis. The control group consisted of 11 individuals without knee replacement surgery. Vicon motion capture system and Plug-in-Gait model were used to collect gait data to obtain marker coordinates and gait parameters. The kinetic energy, potential energy, and rotational energy for each segment in the lower limbs were calculated. The energies in the centre of pelvis were considered as the approximate to the centre of mass. The energy recovery coefficients were analysed for each segment during gait. SPSS was used to identify the differences between different groups. ResultsThe results showed that during walking, the upper leg had the highest recovery coefficient, approximately 40%, followed by the foot at 10%, and the lowest recovery coefficient was observed in the lower leg, approximately 1–3%. However, the energy recovery coefficients at the centre of pelvis were significantly higher in the control group than the TKA and UKA groups by roughly 12%–15%. ConclusionsThe energy difference between the operative and non-operative sides is not significant regardless of the type of surgery. The TKA and UKA groups were more active in potential energy than control group. The upper leg has the highest recovery efficiency of kinetic and potential energy exchanges when walking. The control group used the energy for whole body is better than the patient groups. This study provides a new and useful way to analyze mechanical energy in the lower limbs during gait and could be applied in clinical practice.

Smoking is associated with higher short-term risk of revision and mortality following primary hip or knee arthroplasty: a cohort study of 272,640 patients from the Dutch Arthroplasty Registry.

Patients actively smoking at the time of primary hip or knee arthroplasty are at increased risk of direct perioperative complications. We investigated the association between smoking status and risk of revision and mortality within 2 years following hip or knee arthroplasty. We used prospectively collected data from the Dutch Arthroplasty Register. All primary total hip arthroplasties (THAs), total knee arthroplasties (TKAs), and unicondylar knee arthroplasties (UKAs) with > 2 years' follow-up were included (THA: n = 140,336; TKA: n = 117,497; UKA: n = 14,807). We performed multivariable Cox regression analyses to calculate hazard risks for differences between smokers and non-smokers, while adjusting for confounders (aHR). The smoking group had higher risk of revision (THA: aHR 1.3, 95% confidence interval [CI] 1.1-1.4 and TKA: aHR 1.4, CI 1.3-1.6) and risk of mortality (THA: aHR 1.4, CI 1.3-1.6 and TKA: aHR 1.4, CI 1.2-1.6). Following UKA, smokers had a higher risk of mortality (aHR 1.7, CI 1.0-2.8), but no differences in risk of revision were observed. The smoking group had a higher risk of revision for infection following TKA (aHR 1.3, CI 1.0-1.6), but not following THA (aHR 1.0, CI 0.8-1.2). This study showed that the risk of revision and mortality is higher for smokers than for non-smokers in the first 2 years following THA and TKA. Smoking could contribute to complications following primary hip or knee arthroplasty.

Does robotic-assisted unicompartmental knee arthroplasty restore native joint line more accurately than with conventional instruments?

The study's primary aim is the restoration of native joint line in patients having robotic-assisted unicondylar knee arthroplasty and conventional unicondylar knee arthroplasty. Literature in the past has demonstrated that reducing the joint line can result in greater failure rates. This is a prospective cohort investigation of patients who had medial UKA between March 2017 and March 2022.All patient's pre-operative and post-operative radiological joint line assessments were examined by two observers by Weber's methods. Robotic-assisted UKA performed with hand-held image-free robots was compared to conventional UKA groups. The distal position of the femoral component was higher in Group B utilizingconventional tools than in Group A employing robotic-assisted UKA. This positional difference was statistically significant. The mean difference among the pre-operative and post-operative joint lines in Group A was 1.6 ± 0.49 (range 0.8mm-2.4mm), while it was 2.47 ± 0.51 (range 1.6mm-3.9mm) (p 0.005) in Group B. In Group A, a greater percentage of the subjects (64%) attained a femoral component position within two millimetersfrom the joint line, whereas just 18% in Group B did. When compared with the conventional UKA technique, the meticulous attention to detail and planning forligament rebalancing when using the robotic-assisted UKA technique not solely enhancesurgical precision for implant placing but additionally provides excellent native joint line restoration and balancing. For validation of its longevity and survivability, the cohort must be tracked for a longer period of time.

Knee

The December 2023 Knee Roundup360 looks at: Obesity is associated with greater improvement in patient-reported outcomes following primary total knee arthroplasty; Does mild flexion of the femoral prosthesis in total knee arthroplasty result in better early postoperative outcomes?; Robotic or manual total knee arthroplasty: a randomized controlled trial; Patient-relevant outcomes following first revision total knee arthroplasty, by diagnosis: an analysis of implant survivorship, mortality, serious medical complications, and patient-reported outcome measures using the National Joint Registry data set; Sagittal alignment in total knee arthroplasty: are there any discrepancies between robotic-assisted and manual axis orientation?; Tourniquet use does not impact recovery trajectory in total knee arthroplasty; Impact of proximal tibial varus anatomy on survivorship after medial unicondylar knee arthroplasty; Bone cement directly to the implant in primary total knee arthroplasty?; Maintaining joint line obliquity optimizes outcomes in patients with constitutionally varus knees.

Assessment of Patient Satisfaction and Outcomes After Outpatient Joint Arthroplasty in Academic Medical Centers

BackgroundThere is limited literature evaluating patient satisfaction and outcomes after outpatient joint arthroplasty procedures in academic medical centers (AMCs). The aims of this study are to determine: (1) patients' desires to repeat their procedures and be discharged on the same day, (2) patient-reported outcome measures (PROMs), (3) time to discharge, (4) readmission rates, and (5) factors that predict PROMs in patients undergoing outpatient joint arthroplasty in AMCs. MethodsA prospective survey was completed by 66 total hip arthroplasty (THA), 35 total knee arthroplasty (TKA), and 180 unicondylar knee arthroplasty (UKA) outpatients who underwent surgery from May 2018 to December 2020 in 2 AMCs. The survey consisted of questions regarding hip or knee PROMs (Hip Disability and Osteoarthritis Outcome Score for Joint Replacement, and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement), satisfaction with outpatient procedures and discharges, and reasons for readmissions. Linear regression analysis was conducted with statistical significance set at P < .05. Results100% of THA, 93.8% of TKA, and 93.0% of UKA outpatients stated that they would re-elect to undergo their respective procedure. Furthermore, 94% of THA, 81% of TKA, and 95% of UKA patients stated they would like same-day discharge again. THA, TKA, and UKA patients reported respective mean PROM scores of 94.7, 89.9, and 86.1. Readmission rates were 1.5%, 0.0%, and 0.5%, for THA, TKA, and UKA, respectively. ConclusionsPatients who underwent outpatient joint arthroplasty procedures at 2 AMCs experienced minimal readmissions and reported a high desire to repeat their outpatient procedures.

No Difference in Range of Motion, Components, or Complications Following Conversion of Robotic-Assisted Total Knee Arthroplasty Compared to Manual TKA After Undergoing Manual or Robotic-Assisted Unicompartmental Knee Arthroplasty

BackgroundConversion surgery from unicondylar knee arthroplasty (UKA) to total knee arthroplasty (TKA) remains a challenge due to scarring, implant/cement removal, and loss of bony landmarks. Robotic-assisted (RA) TKA may assist in challenges seen in manual conversion TKA. The aim of this study is to identify if there are differences in components and functional outcomes dependent on manual/RA primary UKA and conversion TKA. MethodsA retrospective chart review was performed on patients undergoing conversion from UKA to TKA over a 10-year period at a single institution. Data extracted included surgical technique, reason for UKA failure, range of motion at 1 year, need for augments, and utilization of revision components. ResultsForty-nine patients (50 knees) with a UKA converted to a TKA were divided into 4 groups based on primary and conversion surgery: manual-to-manual (n = 11), manual-to-robot (n = 11), robot-to-manual (n = 11), and robot-to-robot (n = 17). There was no difference in need for augments (P = .376), size of poly (P = .23), postoperative flexion (P = .52), or extension (P = .76) at 1 year between the 4 groups. However, patients with primary manual UKA did require significantly more augments during revision (P = .032). ConclusionsOur study did not show any statistically significant differences of primary RA or manual UKA to RA or manual TKA in terms of range of motion at 1 year, complications, or differences in components. RA conversion from UKA to TKA is a new but equivalent technique to manual conversion. Primary surgery may impact the requirement for augments during conversion surgery.

Robotic arm-assisted unicondylar knee arthroplasty resulted in superior radiological accuracy: a propensity score-matched analysis

IntroductionUnicompartmental knee arthroplasty (UKA) is an effective surgical treatment for medial compartment arthritis of the knee, yet surgical outcomes are directly related to surgical execution. Robotic arm-assisted surgery aims to address these difficulties by allowing for detailed preoperative planning, real-time intraoperative assessment and haptic-controlled bone removal. This study aimed to compare the clinical and radiological outcomes between conventional manual mobile bearing and robot arm-assisted fixed bearing medial UKA in our local population.Materials and methodsThis is a retrospective case–control study of 148 UKAs performed at an academic institution with a minimum of 1-year follow-up. 74 robotic arm-assisted UKAs were matched to 74 conventional UKAs via propensity score matching. Radiological outcomes included postoperative mechanical axis and individual component alignment. Clinical parameters included a range of motion, Knee Society knee score and functional assessment taken before, 6 and 12 months after the operation.ResultsRobot arm-assisted UKA produced a more neutral component coronal alignment in both femoral component (robotic -0.2 ± 2.8, manual 2.6 ± 2.3; P = 0.043) and tibial component (robotic -0.3 ± 4.0, manual 1.7 ± 5.3; P < 0.001). While the postoperative mechanical axis was comparable, robot arm-assisted UKA demonstrated a smaller posterior tibial slope (robotic 5.7 ± 2.7, manual 8.2 ± 3.3; P = 0.02). Clinical outcomes did not show any statistically significant differences.ConclusionCompared with conventional UKA, robotic arm-assisted UKA demonstrated improved component alignment and comparable clinical outcomes. Improved radiological accuracy with robotic-arm assistance demonstrated promising early results.

UNICONDYLAR KNEE ARTHROPLASTY — PROS AND CONS (LITERATURE REVIEW)

In the modern world, despite the increased availability of hightech orthopedic care, the number of patients with gonarthrosis does not decrease, and thanks to public awareness, more and more people turn to orthopedists for surgical help. Due to its high efficiency, the leading role in the treatment of terminal gonarthrosis has been firmly occupied by total knee arthroplasty for more than four decades. Unicondylar knee arthroplasty in patients with unilateral arthrosis allows to largely preserve physiological kinematics, to achieve minimal bone and soft tissue traumatization during surgery and, as a result, to obtain a higher functional result. The objective of the work is to analyze the data of the world literature regarding unicondylar knee arthroplasty, its advantages and disadvantages. Material and methods. The authors analyzed the publications devoted to single-condylar knee arthroplasty from the Google search engine, scientific and metric electronic databases PubMed, Medline and other relevant sources of scientific and medical information. Correct patient selection is vital to ensure a successful outcome with OEKS. The main indication for OEKS is deforming arthrosis of the II–III century. with a predominant lesion of the internal part of the knee joint and varus deformation of the lower limb or with a more pronounced pathology of the external part of the knee joint and valgus deformation of the lower limb. Results. The authors analyzed the literature sources on single-condylar endoprosthesis of the knee joint. Indications, contraindications, biomechanical features, type of endoprosthesis fixation, type of endoprosthesis platform, features of lateral gonarthrosis, and complications of single-condylar knee arthroplasty are determined. Conclusions. The analysis of selected literary sources showed that single-condylar arthroplasty of the knee joint is an effective means of preserving the bone. However, careful patient selection and precision of surgical technique remain the key to a successful outcome.

Published Comorbidity Indices Poorly Identify Patients at Risk for Failing to Achieve Same Day Discharge Following Unilateral Unicondylar Knee Arthroplasty

Published Comorbidity Indices Poorly Identify Patients at Risk for Failing to Achieve Same Day Discharge Following Unilateral Unicondylar Knee Arthroplasty

Dizde Medial Kompartman Artrozlu Hastalarda Uygulanan Unikondiler Diz Artroplastisi Cerrahisinin Kısa-Orta Dönemde Retrospektif Sonuçları

Aim: The aim of this study was to compare of preoperative and postoperative clinical and radiological findings of the patients with medial compartmental artrosis who underwent the surgery of the unicondylar knee prosthesis. Decrease or disappearance of patient's pain level, assessment of the quality of life of these patients and Knee Society Score (KSS), KSS function score and VAS score compared in both groups. &#x0D; &#x0D; &#x0D; &#x0D; Materials and methods: Between January 2014 and December 2017 in the Orthopaedic Clinic of Health Sciences University Izmir Bozyaka Training and Research Hospital, patients who underwent Unicondyler Knee Arthroplasty surgery due to medial compartmental arthrosis were included in the study. Retrospectively, demographic data, weight bearing anteroposterior-lateral knee x-ray graphics, orthoroentgenogram, KSS and VAS scores, preoperative and postoperative knee range of motions were recorded. &#x0D; &#x0D; &#x0D; &#x0D; Results: 44 knees of the 38 patients are evaluated, the mean age of the 44 cases was 57.09 years. Of the 44 cases, the mean follow-up period was 40,08 months. According to the Knee Society Score system, the preoperative score was 55.64 and postoperative 83.32; the KSS function score was 83.75 before the operation and 93.98 postoperatively. The mean range of motion was 107.61 degrees preoperatively and 118.52 degrees postoperatively. &#x0D; &#x0D; &#x0D; &#x0D; Conclusion: The short-mid-term results of our cases are similar as literature which compares Knee Society Score and the radiographical evaluation. Unicondylar knee arthroplasty can be performed in selected appropriated cases.

Regional Trends in Unicondylar and Patellofemoral Knee Arthroplasty: An Analysis of the American Joint Replacement Registry

BackgroundAs the popularity of unicondylar knee arthroplasty (UKA) and patellofemoral arthroplasty (PFA) have expanded, more patients who have limited arthritis are undergoing partial knee arthroplasty. No studies have evaluated if any regional differences in the United States (U.S.) exist between partial versus total knee arthroplasty (TKA). The purpose of this study was to utilize the American Joint Replacement Registry to evaluate regional differences in UKA, PFA, and TKA. MethodsThe American Joint Replacement Registry was queried for all TKA, PFA, and UKA procedures between 2012 and 2021. Surgical volume was compared between the Midwest (MW), Northeast (NE), South, and West (W) regions. Trends were compared using multivariate logistic regression analyses and least squared mean logistic regression models. ResultsSince 2012, there has been a steady increase in the amount of UKAs performed across the U.S., except during the COVID-19 pandemic when numbers decreased. Logistic regression analyses demonstrated a higher likelihood of receiving a UKA compared to TKA in the NE compared to other regions, and higher likelihood of receiving a PFA in the NE and W compared to other regions over the study period. Other factors that increased the likelihood of having a UKA nationally were men, the procedure being performed at a teaching hospital, and having surgery in urban areas. Patients were more likely to have a PFA in the NE compared to the S and MW, and higher odds in the South and W compared to the MW, with rates of PFA consistently lower in the MW compared to other regions. ConclusionsPatients were more likely to have a UKA in the NE compared to other regions of the country. Patients had higher odds of having a PFA in the NE and W regions relative to the MW. Men had higher odds of having either UKA or PFA than women across the nation.

Study of bone density according to СT data before and in the remote period after unicondylar knee arthroplasty

Background. Unicondylar knee arthroplasty has become popular among orthopedists in recent years. The main complication of this technology is the instability of the tibial component of the endoprosthesis due to the development of local osteoporosis in the area of arthroplasty. Patients with decreased bone density are at high risk of developing instability of the tibial component of the endoprosthesis. Therefore, determining the levels of bone mineral density in patients with osteopenia before arthroplasty make it possible to calculate the risk of complications in the long term. Objective: to evaluate the bone mineral density according to the computed tomography (CT) of the tibial plateau resection zone for unicondylar arthroplasty in patients at risk. Materials and methods. The state of three cortical layer zones was assessed: anterior, middle, posterior and 4 zones of the plateau cut plane. The optical density of bone tissue was measured on CT images of the tibial plateau of the knee joint using the Hounsfield scale. Changes in bone structures in the area of placing tibial component of the endoprosthesis were studied in 2 groups of patients: group I — ten individuals who had undergone unicondylar knee arthroplasty 3–6 years ago and complained of negative phenomena in the prosthetic knee, group II — ten patients who had undergone unicondylar arthroplasty 1.2–2 years ago. These patients underwent CT densitometry at the follow-up examination. Results. Before arthroplasty, the maximum optical density of bone tissue was statistically the same. The density of the cortical layer was maximal in the anterior part of the bone (~ 720 HU), minimal — in the posterior part (580 HU). For the spongy bone zone, the maximum optical density was observed in the anterior part (~ 470 HU), and in the posterior part, it was lower. In 3–6 years, patients of group I showed a significant decrease in the optical density of the bone, both in its cortical layer and in the cancellous tissue. The greatest losses were detected in the medial zones of the cancellous bone. Patients had areas of cortical layer resorption, and in some individuals, its complete absence. At the same time, the absorption index of the cortical layer in the areas of destruction did not exceed 100 HU. The maximum optical density of the cortical layer in the zones also decreased. In patients of group II, 1.5–2 years after arthroplasty, there were no noticeable changes in the bone structures in the surgery area. Changes occurred in the medial zones of the cancellous bone of the tibial plateau. Patients with osteopenia reported changes in bone optical density already in the first years after arthroplasty, although they do not lead to instability of the tibial component of the endoprosthesis. Conclusions. Patients with decreased bone density (osteopenia) during joint arthroplasty are at risk of developing local osteoporosis in the area of bone resection. The first signs of resorption of the cancellous bone can be observed 1.5–2 years after arthroplasty. Timely treatment measures can slow down the further progression of osteoporosis.

The Length of Incision in Unicondylar Knee Arthroplasty Is More Affected by the Patient's Height Than Their Weight.

Objective Obesity leads to osteoarthritis due to increased loading forces on joint cartilage and inflammatory agents released from adipose tissue. In patients with a high body mass index (BMI), during hip and total knee arthroplasty, surgical technical challenges such as longer incisions and wider exposure are encountered, resulting in increased postoperative complications (wound healing problems and infection, venous thromboembolism (VTE)- pulmonary embolism (PE), dislocation, early implant failure) and ultimately decreased patient satisfaction and implant survival. This study investigates whether BMI, height, weight, and patient age are associated with longer incisions in patients undergoing unicondylar knee prosthesis (UKP) placement. Method Between January 2017 and December 2018, 30 patients (29 females and 1 male) who underwent UKP surgery due to medial gonarthrosis were included in the study. The UKP used in the procedures was the Oxford Knee Phase III by Biomet Ltd., UK. The study comprised 43 knees, 13 being bilateral cases, 8 on the right, and 9 on the left. Data regarding the patient's height, weight, BMI, age, and the operated side were collected and compiled. The relationships between these variables and the surgical incision length were statistically analyzed. Results The average age of the patients was 66.3 years, with an average weight and height of 77.6 kg (ranging from 62 to 98 kg) and 167 cm (ranging from 150 to 184 cm), respectively. The lengths of the surgical incisions ranged from 70 mm to 160 mm, with an average length of 124.5 mm. When comparing the incision lengths between the right and left sides, it was observed that the incisions on the left side were longer. The average incision length on the right side was 122.09 mm, while on the left, it was 126.86 mm. Moreover, in the 13 patients who underwent bilateral surgery, this difference in incision length was even more pronounced. The average incision length on the right side was 117.15 mm, whereas on the left, it was 124.23 mm. Bivariate correlation analyses were performed to examine the relationship between the length of the incision and BMI and age. However, no significant relationship was found between the incision length and BMI or age. On the other hand, there was a correlation between the patient's weight values and the incision length (p < 0.05, correlation 0.335). Furthermore, a higher correlation was observed between the patient's height and the incision length (p < 0.01, correlation 0.595). Conclusion The latest advances in surgical techniques and instrumentation have enabled surgeons to perform the procedure using a reliable mini-incision approach. Mid-term evaluation of UKP with mini-incision shows faster recovery and lower morbidity. The findings show that in UKP, the length of the surgical incision is more strongly related to the patient's height than their weight.

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.

LONG-TERM RESULTS OF PER-OPERATIVE KNEE ARTHROSCOPY IN CONFIRMING SUITABILITY FOR UNICOMPARTMENTAL KNEE ARTHROPASTY

AbstractIntroductionPatient selection is key to the success of medial unicondylar knee arthroplasty (UKA). Progression of arthritis is the most common indication for revision. Various methods of assessing the lateral compartment have been used including stress radiography, radioisotope bone scanning, MRI, and visualisation at the time of surgery. Arthroscopy is another means of assessing the integrity of the lateral compartment.MethodsWe used per-operative arthroscopy as a means to confirm suitability for UKA in a consecutive series of 279 Oxford medial UKA. This study reports the long-term results of a previously published cohort of knees. 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 the indication for revision in similar proportions for the three groups (Group 1: 32.3%, Group 2: 35.7% and Group 3: 33.5%). Following per-operative arthroscopy 21.6% (77/356) of knees underwent a change of surgical plan from UKA to TKA.ConclusionPer-operative arthroscopy may improve medium-term medial unicompartmental knee survivorship but does not improve long-term survivorship nor reduce revision due to progression of arthritis.