A finite element analysis of patellofemoral joint biomechanics: Exploring potential causes of postoperative anterior knee pain following unicompartmental knee arthroplasty.

Purpose: Anterior knee pain is a common complication following unicompartmental knee arthroplasty (UKA). This study aimed to elucidate the mechanism of anterior knee pain after UKA by examining the biomechanical characteristics of the patellofemoral joint. Methods: This study employs the finite element analysis method. A healthy model of the right lower limb was created using CT scans of an intact right lower limb from a healthy woman. Based on this model, a preoperative pathological model was generated by removing the meniscus and part of the articular cartilage. The UKA prosthesis was then applied to this model with five different bearing thicknesses: 5 mm, 7 mm, 10 mm, 11 mm, and 13 mm. To simulate various degrees of knee joint flexion, the femur was rotated relative to the knee joint's rotational axis, producing lower limb models at flexion angles of 0°, 30°, 60°, 90°, and 120°. We applied a constant force from the center of the femoral head to the center of the ankle joint to simulate lower limb loading during squatting. The simulations were conducted using Ansys 17.0. Results: Both overstuffing and understuffing increased the peak stress on the patellar cartilage, with overstuffing having a more pronounced effect. Compared to healthy and balanced models, overstuffed and understuffed models exhibited abnormal stress distribution and stress concentration in the patellar cartilage during knee flexion. Conclusion: Overstuffing and understuffing lead to residual varus or valgus deformities after UKA, causing mechanical abnormalities in the patellofemoral joint. These abnormalities, characterized by irregular stress distribution and excessive stress, result in cartilage damage, exacerbate wear in the patellofemoral joint and consequently lead to the occurrence of anterior knee pain.

The efficacy of patellar denervation on prognosis and kneeling capacity after unicompartmental knee arthroplasty: a randomized clinical trial.

OBJECTIVE: The aim of this study was to investigate the effect of patellar denervation (PD) on pain, function and ability to kneel after unicompartmental knee arthroplasty (UKA). METHODS: Patients with medial knee osteoarthritis who underwent UKA were prospectively selected. Patients were randomly divided into PD and non-PD groups based on whether patellar denervation was performed. Clinical assessment was performed using the Hospital for Special Surgery (HSS) knee score, Kujiala score, visual analogue scale (VAS) and forgotten joint score (FJS-12), as well as postoperative complications were recorded. The patients' postoperative self-perception and actual ability to perform different kneeling positions were assessed in the two groups. RESULTS: UKA patients treated with PD achieved better Kujiala scores and FJS-12 scores, reduced anterior knee pain and improved kneeling ability postoperatively, validating the effectiveness of PD in UKA. Perception and actual performance of kneeling remained mismatched in PD patients, but performance during different kneeling activities was generally better than in non-PD patients. TRIAL REGISTRATION: Clinical Trial Registration: ChiCTR1900025669. CONCLUSION: Patellar denervation can safely and effectively improve patellofemoral joint function, pain and kneeling ability in the early postoperative period after UKA.

Medial collateral ligament section during unicompartmental knee arthroplasty managed by direct repair and fascia lata augmentation autograft: a case report and surgical technique.

Background: The medial collateral ligament (MCL) is crucial for ensuring implant stability after unicompartmental knee arthroplasty (UKA). Intraoperative MCL lesions can cause valgus instability, affecting function and implant longevity, and thereby negatively impacting the patient's outcome. Every surgeon who performs UKA may encounter this complication in their daily practice. In this context, this case report presents a rescue technique. The existing literature does not specify a protocol for managing this complication. This article presents the first instance of accidental midsubstance section of the MCL during medial UKA, managed through primary suture and augmentation repair with a fascia lata (FL) autograft. The procedure was subsequently replicated step by step on an anatomical specimen. Case Description: A 54-year-old woman, previously successfully treated with right medial UKA, was referred to our clinic following an unsuccessful attempt at conservative treatment for osteoarthritis in the left knee. Scheduled for a left medial UKA, an inadvertent midsubstance transection of the deep part of the MCL was encountered during the procedure, resulting in valgus instability. The MCL was promptly repaired and reinforced using an ipsilateral FL augmentation autograft. Subsequent UKA surgery was successfully completed. Follow-up at one year revealed favorable post-operative outcomes, with symmetrical stability on stress radiographs and no indications of early loosening. Conclusions: To our knowledge, this article represents the first documentation of the direct management for this rare yet severe complication. This case report could therefore inspire any surgeon facing this complication. The technique, grounded in biomechanical principles, ensures direct medial stability whilst allowing uninterrupted continuation of the initial procedure. Characterized by simplicity and reproducibility, the approach demonstrates favorable short-term outcomes. Because the results should be interpreted considering the limited impact of a case report, further prospective studies are essential to substantiate and strengthen these findings.

Fixed-Bearing Medial Unicompartmental Knee Arthroplasty: New Indications and the Anterior Cruciate Ligament-Deficient Knee.

The anterior cruciate ligament (ACL)-deficient osteoarthritic knee is a challenging disease entity which requires careful thought to restore function and return to activities. Advancements in technology and surgical techniques have expanded indications for unicompartmental knee arthroplasty (UKA), to include ACL-deficiency in select patients. An improved understanding of the ACL-deficient osteoarthritic knee can aid in clinical and surgeon decision-making to restore knee function. This review will discuss current practice guidelines for the ACL-deficient knee with single-compartment osteoarthritis including pathoanatomy, indications, contraindications, technical considerations, and clinical outcomes.

Mid-term outcomes of medial metal backed and all-polyethylene unicompartmental knee arthroplasty in obese patients: a retrospective propensity-matched analysis.

BACKGROUND: This retrospective study compares the outcomes of unicompartmental medial fixed-bearing knee arthroplasty (mUKA), involving a cemented metal-backed (MB) or an all-polyethylene (AP) tibial component, performed in obese patients with a body mass index (BMI) > 30 with a follow-up of at least 5 years. METHODS: The institutional database was mined for primary mUKAs involving an MB or an AP tibial component (MB-UKA and AP-UKA groups, respectively) performed from January 2015 to August 2019. Patient demographics and patient-reported outcome measures (PROMs) were compared and a propensity score matching (PSM) analysis (1:1) using multiple variables was conducted. RESULTS: PSM analysis yielded 37 pairs of obese MB-UKA and AP-UKA patients. At 5 years, the Knee Society Function Score (KSFS) was 75.1 ± 10.6 in MB-UKA and 79.4 ± 9.1 in AP-UKA patients (p = 0.029), and the Oxford Knee Score (OKS) was 38.1 ± 4.4 in MB-UKA and 40.6 ± 5.7 in AP-UKA patients (p = 0.011). CONCLUSION: At five-year follow-up, in a matched group of obese MB-UKA and AP-UKA patients, the AP-UKA group achieved better KSFSs and OKSs. Both the AP and the MB tibial components were able to bring about a significant improvement of the most widely used PROMs.

Correlation of revision rate of unicompartmental knee arthroplasty with total knee arthroplasty: a meta-analysis of clinical studies and worldwide arthroplasty registers.

INTRODUCTION: The purpose of this study was to elucidate differences and similarities in revision rates amongst studies and national registers featuring total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA). Thereby comparability and reproducibility between study and register findings should be created. MATERIALS AND METHODS: Clinical studies published between 2004 and September 2023 involving TKA or UKA were reviewed for total arthroplasty numbers, revision rates and demographic data. Findings were calculated as "revisions per 100 component years (CY)" and divided according to the nationality of the center. National arthroplasty registers were searched for numbers of arthroplasties and revisions alongside with demographic data. Revision rates in registers were compared to one another and comparison to revision rates from collected studies was drawn. RESULTS: After evaluation, 98 studies and seven registers met our inclusion criteria and were included in this study. Cumulative percent revision rate in studies was 3.35% after a mean follow-up of 5.7 years, corresponding to 0.71 revisions per 100 CY for TKA and 7.67% after a mean follow-up of 4.9 years, corresponding to 1.3 revisions per 100 CY for UKA. Registers showed mean overall revision rates of 5.63% for TKA and 11.04% for UKA. CONCLUSIONS: A positive correlation of revision rates of TKA and UKA in studies and registers was found, with overall revision rates of UKA comparted to TKA being 2.29 times higher in clinical studies and 1.96 times higher in registers. Revision rates in registers were 1.56 times higher than presented in clinical studies.

Clinical outcomes of unicompartmental knee arthroplasty and total knee arthroplasty in the same patient.

BACKGROUND: Osteoarthritis has become the predominant manifestation of arthritic conditions on a worldwide scale and serves as a significant instigator of pain, impairment, and increasing socio-economic strain on a global level. The ongoing discourse on the choice between total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) for patients suffering from anterior medial osteoarthritis continues to ignite scholarly controversy. Our objective was to assess and compare the clinical outcomes of UKA and TKA within the same patient, hereby offering a novel perspective on this topic. MATERIALS AND METHODS: Fifty-seven individuals who underwent TKA on one knee and UKA on the other knee at the Department of Orthopaedics, First Hospital of Hebei Medical University between March 2019 and March 2024 were analysed for this retrospective study. We conducted a comprehensive examination and evaluation of perioperative laboratory assessments, radiological examinations, knee functionality, contentment levels, and postoperative complications within the two groups. RESULTS: Following surgical procedures, levels of hemoglobin, red blood cells, and albumin were found to be elevated in the UKA group when compared to the TKA group (hemoglobin: 121.2 ± 12.54 vs. 110.1 ± 13.21 g/L; red blood cells: 4.0 ± 0.47 vs. 3.6 ± 0.42 *1012/L; albumin: 37.7 ± 5.66 vs. 35.3 ± 5.23 g/L). There is a significant difference in the hip-knee-ankle angles between the postoperative UKA group and the TKA group (5.3 ± 3.46° vs. 4.1 ± 2.86°, p < 0.05). There existed no notable disparity in postoperative visual analog scale, knee society score, and forgotten joint score between the two groups. However, a remarkable variance was observed in postoperative range of motion between the two groups (116.4 ± 5.96° vs. 108.4 ± 5.32°). CONCLUSION: We found that UKA resulted in less physical strain, less postoperative inflammatory response, improved joint mobility, although with less effective lower limb force line correction compared to TKA. Many patients have shown a preference for UKA and express higher levels of satisfaction with the procedure.

[Research progress in Oxford unicompartmental knee arthroplasty for partial thickness cartilage loss in medial compartment of knee joint].

Objective: To summarize the research progress of Oxford unicompartmental knee arthroplasty (UKA) in treating partial thickness cartilage loss (PTCL) in the medial compartment of the knee joint, aiming to further clarify the indications and optimize the effectiveness of Oxford UKA. Methods: A comprehensive review of recent domestic and international literature on Oxford UKA for PTCL in the medial compartment of the knee joint was conducted to summarize its application and research advancements. Results: Based on current researches, the main indication for Oxford UKA is full thinckness cartilage loss in the medial compartment of the knee joint. Although it has shown certain effectiveness in treating PTCL in the medial compartment of the knee joint, there are also reports of opposite conclusions. Therefore, there is still controversy over whether Oxford UKA can be chosen for PTCL, and the large-sample and multi-center studies are needed to further clarify the controversy. Studies indicate that accurate preoperative assessment of cartilage damage severity is crucial for selecting appropriate candidates for Oxford UKA to optimize postoperative effectiveness. Conclusion: Oxford UKA may represent an effective treatment for patients with PTCL in the medial compartment of the knee joint. However, strict patient selection and precise preoperative evaluation are essential to ensure surgical success and long-term effectiveness.

Comparison of early curative effects of lateral unicompartmental knee arthroplasty with total knee arthroplasty and the legacy constrained condylar knee arthroplasty in the treatment of isolated lateral osteoarthritis: a single-center retrospective study.

BACKGROUND: Aims of this study were to compare the functional and radiographic results, perioperative complication after lateral unicompartmental knee arthroplasty (LUKA) with total knee arthroplasty (TKA) and the legacy constrained condylar knee (LCCK) arthroplasty for the treatment of lateral compartmental knee osteoarthritis (LCKOA), and to provide a basis for the treatment of LCKOA. METHODS: From January 2021 to January 2024, analyzed retrospectively clinical data of 74 patients with LCKOA treated with LUKA, TKA and LCCK arthroplasty. According to the operation plan, the patients were divided into three groups: LUKA group (23 cases), TKA group (23 cases) and LCCK group (28 cases). The changes of hip-knee-ankle (HKA) angle of the affected knee before and after operation were measured. All patients were assessed using the operation time, blood loss during operation, incision length, visual analogue scale (VAS) score before operation and after operation, Hospital for Special Surgery score (HSS), Oxford Knee Score (OKS), range of motion (ROM). RESULTS: All 74 patients were followed up for (2.38 ± 0.33) years. The operation time, blood loss during operation, incision length and VAS score after operation in the LUKA group were significantly less than those in the TKA group and LCCK group (P < 0.05); HKA valgus angle, ROM, HSS score and OKS score of the three groups after operation were significantly better than those before operation (P < 0.05); There was no significant difference among the three groups in HSS score and OKS score (P > 0.05). CONCLUSION: LUKA, TKA and LCCK arthroplasty have good clinical effect in the treatment of LCKOA; Compared with TKA and LCCK arthroplasty, LUKA has the advantages of less trauma, less bleeding, less pain and quick recovery. The short-term effect is satisfactory, and the long-term effect remains to be observed.

Influencing factors of kinesiophobia in knee arthroplasty patients under the social cognitive theory: A structural equation model.

OBJECTIVE: To analyze the path relationships among influencing factors for kinesiophobia in knee arthroplasty patients through a structural equation model. BACKGROUND: The occurrence of kinesiophobia significantly impacts the rehabilitation process of knee arthroplasty patients. However, there is still a need to determine factors that contribute to reducing kinesiophobia. DESIGN: A cross-sectional study was conducted and reported following the STROBE guideline. METHODS: Between February 2022 to October 2022, 162 total knee arthroplasty (TKA) patients and 81 unicompartmental knee arthroplasty (UKA) patients completed a survey. A structural equation modeling (SEM) approach was utilized to analyze the relationships between kinesiophobia and influencing factors (social support, pain resilience, and rehabilitation self-efficacy). Furthermore, multi-group SEM analysis was conducted to examine whether the model equally fitted patients in different types of knee arthroplasty. RESULTS: The direct negative effects of rehabilitation self-efficacy (ß = -0.535) and pain resilience (ß = -0.293) on kinesiophobia were observed. The mediating effect (ß = -0.183) of pain resilience and rehabilitation self-efficacy between social support and kinesiophobia was also significant. The SEM model achieved an acceptable model fit (χ2 = 35.656, RMSEA = 0.031, χ2/df = 1.230, GFI = 0.972, NFI = 0.982, IFI = 0.997, CFI = 0.996). In multicohort analysis, no significant differences were observed among knee arthroplasties (TKA, UKA) (Δχ2 = 4.213, p = 0.648). CONCLUSIONS: Satisfactory social support enhances pain resilience and rehabilitation self-efficacy, so as to reduce kinesiophobia. Future interventions that directly target the assessment and management of kinesiophobia, available social support may help reduce kinesiophobia, and pain resilience and rehabilitation self-efficacy may be critical factors in managing kinesiophobia. RELEVANCE TO CLINICAL PRACTICE: Reducing kinesiophobia in knee arthroplasty patients requires satisfactory social support, pain resilience, and rehabilitation self-efficacy. Therefore, healthcare organizations may implement initiatives to reduce kinesiophobia by taking these factors into account.

The Relationship Between Age and 30-Day Outcomes Following Unicompartmental Versus Total Knee Arthroplasty.

BACKGROUND: Understanding the short-term complication profile following unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA) can improve surgical decision-making and patient outcomes. This study aimed to determine if the difference in risk of 30-day morbidity and mortality between UKA and TKA varied based on patient age. METHODS: This retrospective study of a national quality improvement database using data from 2014 to 2020 included 403,342 patients undergoing UKA (n = 12,324) or TKA (n = 391,018). A generalized additive model evaluated nonlinear relationships between primary outcome and predictors (age, procedure, and procedure × age interaction) using a 1:5 UKA to TKA matched sample. Probabilities and odds ratios (95% confidence interval [CI]) estimated the relative risk of complications by age. RESULTS: In the generalized additive model, TKA patients relative to UKA had 1.30 odds (95% CI 1.19 to 1.43, P < 0.001) of 30-day morbidity and mortality. There was a significant nonlinear relationship between age and primary outcome (P = 0.02), such that the odds were lowest at younger ages. They increased slowly until the age of 65 years, when the slope became steeper. The interaction terms for age and procedure were not significant (P = 0.30). The 30-day probability for short-term complications of a 65-, 75-, and 85-year-olds undergoing UKA was 2.1% (95% CI 1.8 to 2.3), 2.4% (95% CI 2.0 to 2.8), and 3.2% (95% CI 2.3 to 4.1), respectively. The probability of a 65-, 75-, and 85-year-old undergoing TKA was 2.9% (95% CI 2.7 to 3.0), 3.6% (95% CI 3.3 to 3.8), and 5.5% (95% CI 4.7 to 6.3), respectively. CONCLUSIONS: Patients undergoing UKA had a quantifiable lower likelihood of morbidity or mortality than TKA at all ages. These data can provide individualized risk for UKA and TKA across the age spectrum and could be helpful in counseling patients regarding their perioperative risk. LEVEL OF EVIDENCE: III (retrospective comparative study).

[Interpretation of the expert consensus of the British Association for Surgery of the Knee (BASK) and the European Knee Society (EKS) on unicompartmental knee arthroplasty].

Unicompartmental knee arthroplasty (UKA) has a long history and has many advantages in some aspects over total knee arthroplasty (TKA) for patients with suitable indications, but it has not been established as a treatment at the same level with TKA. Therefore, 80 members of the British Association for Surgery of the Knee (BASK) and the European Knee Society (EKS) were invited to attend a joint meeting with the aim of creating an evidence-based consensus statement on UKA, in London, UK (December 2019). A formal consensus process was undertaken at the meeting incorporating a multiple round Delphi exercise, with group discussion of areas of agreement and disagreement between rounds. Five consensus statements were issued: ① UKA should be offered as a successful alternative to TKA in patients undergoing arthroplasty who meet agreed indications. ② When consenting a patient for UKA, information including the benefits and risks that are specific to UKA, should be tailored to and discussed with the individual patient. ③ Evidence suggests that surgeons should avoid low-volume use of UKA to optimise outcomes for their patients. ④ Surgeons should use the contemporary evidence-based indications and contraindications for medial UKA. ⑤ Knee arthroplasty surgeons should have exposure to and training in UKA. On the basis of full study of the consensus, combined with the Expert Consensus on Perioperative Management of Unicompartmental Knee Arthroplasty in China in 2020, this paper elaborates the meaning of the final evidence-based consensus for clinicians' reference.

[Effect of anterior cruciate ligament integrity on the short- and mid-term effectiveness of mobile-bearing medial unicompartmental knee arthroplasty].

Objective: To investigate the effect of anterior cruciate ligament (ACL) integrity on the short- and mid-term effectiveness of mobile-bearing medial unicompartmental knee arthroplasty (UKA). Methods: The clinical data of 128 patients with anteromedial osteoarthritis who underwent mobile-bearing medial UKA between June 2019 and June 2021 was retrospectively analyzed. According to the integrity of ACL structure under direct vision during operation, the patients were divided into normal group (30 cases), synovial defect group (53 cases), and longitudinal split group (45 cases). There was no significant difference in gender, age, body mass index, preoperative knee range of motion (ROM), hip-knee-ankle angle (HKA), Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and other baseline data among the 3 groups ( P>0.05). The knee ROM, KSS score (including clinical and functional scores), WOMAC score (including pain, stiffness, and function scores) before operation and at last follow-up, the Lysholm score, International Knee Documentation Committee (IKDC) score, and Forgetting Joint Score (FJS-12) at last follow-up were recorded and compared among the 3 groups. Imaging examination was performed to evaluate the wear of cartilage in the lateral tibiofemoral compartment and patellofemoral compartment of the knee joint. HKA and posterior tibial slope (PTS) were measured at last follow-up. Results: All the patients of 3 groups were followed up 22-56 months (mean, 40.4 months). There was no significant difference in follow-up time among the 3 groups ( P>0.05). At last follow-up, imaging examination showed no obvious cartilage wear progression of the lateral tibiofemoral compartment and patellofemoral compartment, and no adverse events such as aseptic loosening of the prosthesis, dislocation of the removable pad, or infection occurred during the follow-up. At last follow-up, knee ROM, HKA, KSS scores, and WOMAC scores of the 3 groups significantly improved when compared with preoperative ones ( P<0.05). There was no significant difference in the changes of the above indicators before and after operation, and also the Lysholm score, IKDC score, FJS-12 score, and PTS among the 3 groups ( P>0.05). Conclusion: The integrity of ACL has no significant effect on the short- and mid-term effectiveness of mobile-bearing medial UKA.

All-Polyethylene Tibial Component in Unicompartmental Knee Arthroplasty Offers Excellent Survivorship and Clinical Outcomes at Short-Term Follow-Up: A Multicenter Retrospective Clinical Study.

Background and Objectives: The ten-year survivorship of unicompartmental knee arthroplasty (UKA) is up to 96%, varying from implants and hospitals; however, most of registry studies do not distinguish between metal-back (MB) tibial implants and all-polyethylene (AP) tibial implants. The aim of the present retrospective clinical study was to analyze the clinical outcomes and survivorship of medial and lateral UKA with a newly designed all-polyethylene tibial plateau at short-term follow-up. Materials and Methods: A retrospective analysis of prospectively collected consecutive patients who underwent medial or lateral UKA with AP tibial plateau was conducted, with a minimum follow-up of 1 year. Primary outcomes were clinical score (VAS, OKS, and KOOS) variations from baseline up to the latest follow-up. Secondary outcomes were Likert scale variations from baseline to the follow-up, evaluation of the influence of demographic factors (age and BMI) at the time of surgery on the clinical outcomes, and evaluation of revision rate up to the last follow-up. Results: The final study population included 99 knees. The mean VAS score for the medial group significantly decreased from 7.61 ± 1.65 (pre-intervention) to 2.74 ± 2.26 (post-intervention). Similar improvements were registered for the OKS as well, for both the medial group (from 22.5 ± 12.6 to 36.6 ± 10.6, with a delta of 14.11 (10.05 to 18.17)) and the lateral group (from 22.6 ± 12.6 to 36.9 ± 11.8, with a delta of 14.24 (8.65 to 19.83)). Moreover, all the KOOS subscales reported an amelioration, both in medial UKA and lateral UKA. Furthermore, a logistic regression of delta VAS was performed in relation to the other clinical questionnaires and the demographic factors. For both medial and lateral UKAs, no statistically significant correlation was found between the VAS scale regression and the demographic factors. The survival rate free from any revision of the cohort at the latest follow-up was 96.32%. Conclusions: All-polyethylene tibial component in unicompartmental knee arthroplasty demonstrates significant improvements in clinical scores and a low failure rate at short-term follow-up.

The influence of patellar morphology on clinical outcomes after unicompartmental knee arthroplasty.

PURPOSE: To evaluate the influence of patellar morphology on functional outcomes and patellofemoral joint alignment after unicompartmental knee arthroplasty (UKA). METHODS: This study retrospectively analyzed the clinical and imaging data of 207 patients with osteoarthritis of the unicompartment of the knee who underwent UKA between September 2020 and April 2023. Patients were divided into three groups according to the Wiberg classification: group W1 (I, n = 47), group W2 (II, n = 117), and group W3 (III, n = 43). Knee function was assessed using the Hospital for Specialty Surgery (HSS) knee score and Feller patellar score, and the incidence of anterior knee pain after surgery was recorded and compared. Imaging parameters such as patellar tilt angle (PTA), lateral patellofemoral angle (LPA) and Insall-Salvati ratio (ISR) were measured to assess patellofemoral joint alignment. RESULTS: The HSS scores of the three groups were not statistically different; the postoperative Feller scores of the group W3 differed significantly from those of the other two groups. The incidence of early postoperative anterior knee pain was higher in the group W3 than in the other two groups. The difference between preoperative PTA, postoperative PTA and preoperative LPA in the group W3 and the other two groups was statistically significant. CONCLUSION: Patients with Wiberg III patellae exhibited worse patellar scores, as well as more anterior knee pain and patellar tilt postoperatively. This finding highlights the need for individualized treatment to the Wiberg III patella during UKA to enhance surgical outcomes.

Analysis of causes for revision in unicompartmental knee arthroplasty.

The study by Zhao et al identifies the factors leading to the failure of unicompartmental knee arthroplasty (UKA) in their patients. These factors include substandard suturing of the wound, the presence of osteophytes and intra-articular loose bodies causing impingement, premature loosening of the tibial component, choosing unsuitable patients for the procedure, dislocation of the movable insert, and damage to the anterior cruciate ligament and medial collateral ligament. The findings suggest that employing the correct surgical techniques and indications is essential for successful outcomes in the UKA.

Insights into complications after unicompartmental knee arthroplasty.

Zhao's study, offers a comprehensive analysis of unicompartmental knee arthroplasty (UKA) revision indications. The study provides a detailed, case-by-case analysis of the factors leading to knee revision surgery in 13 patients. Not only elucidates the complexities of UKA revisions but also underscores the importance of continuous improvement in surgical techniques and the adoption of innovative technologies.

Lateral unicompartmental knee arthroplasty: is really a good option?

INTRODUCTION: Lateral unicompartmental knee arthroplasties (LUKA) account for only < 1% of all knee arthroplasties and for only 5-10% of all unicompartmental knee replacements. This means that there is less published literature on these procedures and that the surgeon's experience with them is smaller than with medial UKA. The aim of this study was to analyze the survival and the clinical-functional outcomes of LUKA according to the type of bearing surface (all-polyethylene versus metal-backed) used. MATERIALS AND METHODS: This was a retrospective study including 42 LUKAs operated between 2009 and 2021. Two fixed polyethylene-bearing models were used: the all-polyethylene ACCURIS knee (38%) and the metal-backed Triathlon PKR system (62%). Demographic parameters, knee range of motion (ROM), tibiofemoral alignment, implant survival (as estimated with the Kaplan-Meier curve), and clinical-functional outcomes (as measured with the Knee Society Score) were analyzed. RESULTS: Average patient age was 65.5 (range, 36-87) years and mean follow-up was 8.2 (range, 2.1-12.8) years. Thirty LUKAs (71.4%) were implanted in women. The main reason for performing a LUKA was osteoarthritis (88.1%). No patient developed post-surgical complications or had to be re-operated. Overall LUKA survival was 100% at 1-year and 5-year's follow-up. Knee Society Score, knee ROM and tibiofemoral alignment all improved significantly post-surgery (p < 0.001). The clinical Knee Society Score increased from 46.5 ± 14.5 pre-surgery to 93.5 ± 10.3 post-surgery, the functional Knee Society Score increased from 48.1 ± 13.5 pre-surgery to 94.6 ± 9.3 post-surgery, maximum flexion increased from 108.5 ± 8.7 degrees pre-surgery to 121 ± 8.9 degrees post-surgery and tibiofemoral alignment was corrected from 13.1 ± 1.74 degrees pre-surgery to 5.7 ± 0.8 degrees post-surgery. There were no statistically significant clinical-functional improvement or knee ROM differences between groups (p < 0.05, respectively). CONCLUSION: LUKA is a valid and definitive option for patients with lateral tibiofemoral osteoarthritis, with a survival rate of > 95% at 5-years follow-up. Clinical-functional outcomes are the same, irrespective of the tibial component used.

Cemented versus cementless Oxford unicompartmental knee arthroplasty for the treatment of medial knee osteoarthritis: an updated systematic review and meta-analysis.

OBJECTIVE: This meta-analysis sought to compare the efficacy of cemented versus cementless Oxford unicompartmental knee arthroplasty(UKA) for the treatment of medial knee osteoarthritis. METHODS: A comprehensive search of the following databases was conducted: Pubmed, The Cochrane Library, China National Knowledge Infrastructure (CNKI), Embase, the Web of Science, and MEDLINE. The objective was to identify literature comparing cemented versus cementless Oxford unicompartmental knee arthroplasty for the treatment of medial knee osteoarthritis. Duplicate literature, low-quality literature, literature with incompatible observations, and literature for which the full text was not available were excluded. Two independent researchers employed the Cochrane Risk Assessment Tool and the Newcastle-Ottawa Scale (NOS) to evaluate the quality of the included literature. The data then were extracted and subsequently meta-analyzed using RevMan 5.4. RESULTS: A total of 12 papers were included in the analysis, encompassing a cumulative of 2558 cumulative cases. Of these, 1258 were cemented and 1300 were cementless. A meta-analysis was conducted to compare the outcomes of cemented versus cementless Oxford UKA. The Oxford UKA group exhibited a significantly longer surgery time than the cementless Oxford UKA group [mean difference (MD) = 9.91, 95% confidence interval (CI) (7.64,12.17)]. Additionally, the cemented Oxford UKA group demonstrated a significantly lower knee OKS score compared to the cementless Oxford UKA group. The mean difference (MD) was - 1.58 (95% CI: -2.30, -0.86), indicating a significantly lower score for the cemented Oxford UKA group. Similarly, the mean difference (MD) was - 1.8 for the knee KSS clinical score, indicating a significantly lower score for the cemented Oxford UKA group. The results demonstrated that the knee KSS functional score was significantly lower in the cemented Oxford UKA group than in the cementless Oxford UKA group [MD=-1.72, 95% CI (-3.26, -0.37)]. 95% CI (-3.27,-0.17)], the cemented Oxford UKA group exhibited a significantly higher incidence of radiolucent lines around the prosthesis than the cementless Oxford UKA group [ratio of ratios (OR) = 3.62, 95% CI (1.08,12.13)]. The revision rate was significantly higher in the cemented Oxford UKA group than in the cementless Oxford UKA group [OR = 2.22, 95% CI (1.40,3.53)]. However, no significant difference was observed between the two groups in terms of reoperation rate, five-year prosthesis survival rate, and complication rate. CONCLUSIONS: The findings indicated that, in comparison to cemented Oxford UKA, cementless Oxford UKA resulted in a reduction in surgical time, an improvement in knee OKS score, KSS clinical score, and KSS functional score, and a decrease in the incidence of periprosthetic radiolucent lines and the rate of revisions.

Does patient-specific instrument or robot improve imaging and functional outcomes in unicompartmental knee arthroplasty? A bayesian analysis.

INTRODUCTION: This study conducted a Bayesian network meta-analysis (NMA) to compare the imaging and functional outcomes of patient-specific instrument-assisted unicompartmental knee arthroplasty (P-UKA), robot-assisted unicompartmental knee arthroplasty (R-UKA), and conventional unicompartmental knee arthroplasty (C-UKA). MATERIALS AND METHODS: A comprehensive search was performed on five electronic databases and major orthopedic journals as of September 24, 2023. We included randomized controlled studies featuring at least two interventions of P-UKA, R-UKA, or C-UKA. Primary outcomes encompassed the deviation angle of hip-knee-ankle angle, as well as the coronal and sagittal plane alignment of femoral and tibial components. Secondary outcomes included patient-reported outcome measures (PROM), surgery time, revision rate, and complication rate. Bayesian framework was employed for risk ratio (RR) or mean deviation (MD) analysis, and treatment hierarchy was established based on rank probabilities. RESULTS: This NMA included 871 knees from 12 selected studies. In sagittal plane, R-UKA exhibited a significantly reduced deviation angle of femoral component compared to P-UKA (MD: 4.16, 95% CI: 0.21, 8.07), and of tibial component in comparison to C-UKA (MD: -2.45, 95% CI: -4.20, -0.68). Notably, the surgery time was significantly longer in R-UKA than in C-UKA (MD: 15.98, 95% CI: 3.11, 28.88). However, no significant differences were observed in other outcomes. CONCLUSION: Compared with P-UKA or C-UKA, R-UKA significantly improves the femoral and tibial component alignment in the sagittal plane, although this does not translate into discernible differences in functional outcomes. Comprehensive considerations of economic and learning costs are imperative for the judicious selection of the appropriate procedure.