Analysis of the causes of primary revision after unicompartmental knee arthroplasty: A case series

BACKGROUND Unicompartmental knee arthroplasty(UKA)has great advantages in the treatment of unicompartmental knee osteoarthritis,but its revision rate is higher than that of total knee arthroplasty.AIM To summarize and analyse the causes of revision after UKA.METHODS This is a retrospective case series study in which the reasons for the first revision after UKA are summarized.We analysed the clinical symptoms,medical histories,laboratory test results,imaging examination results and treatment processes of the patients who underwent revision and summarized the reasons for primary revision after UKA.RESULTS A total of 13 patients,including 3 males and 10 females,underwent revision surgery after UKA.The average age of the included patients was 67.62 years.The prosthesis was used for 3 d to 72 months.The main reasons for revision after UKA were improper suturing of the surgical opening(1 patient),osteophytes(2 patients),intra-articular loose bodies(2 patients),tibial prosthesis loosening(2 patients),rheumatoid arthritis(1 patient),gasket dislocation(3 patients),anterior cruciate ligament injury(1 patient),and medial collateral ligament injury with residual bone cement(1 patient).CONCLUSION The causes of primary revision after UKA were gasket dislocation,osteophytes,intra-articular loose bodies and tibial prosthesis loosening.Avoidance of these factors may greatly reduce the rate of revision after UKA,improve patient satisfaction and reduce medical burden.

Internal fixation and unicompartmental knee arthroplasty for an elderly patient with patellar fracture and anteromedial osteoarthritis:A case report

BACKGROUND Open reduction and internal fixation(ORIF)is the traditional surgical treatment for patellar fractures,and unicompartmental knee arthroplasty(UKA),especially Oxford UKA,has been increasingly used in patients with medial knee osteoarthritis(OA).However,the process of choosing treatment for patients with both patellar fractures and anteromedial knee OA remains unclear.We present the case of a patient with a patellar fracture and anteromedial OA.CASE SUMMARY We present the case of a 72-year-old woman with a history of bilateral medial compartment OA of the knees and a right Oxford UKA.She also experienced a recent left patellar fracture.ORIF and Oxford UKA were performed in a single stage.The patient showed excellent postoperative clinical results.CONCLUSION ORIF and Oxford UKA can be performed simultaneously for patients with patellar fracture and anteromedial OA on the same knee.

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.

How to manage and avoid revision after unicompartmental knee arthroplasty?

The article by Zhao et al presents a retrospective case series on the reasons for initial revision after unicompartmental knee arthroplasty(UKA).Clarifying the reasons that may cause UKA revision can further reduce the rate of revision UKA,focusing on gasket dislocation,osteophytes,intra-articular loose bodies,and tibial prosthesis loosening.This article provides valuable insights,not only by detailing the revision status of 13 patients who underwent revision after initial UKA but also by providing a comprehensive analysis of the incidence of revision after initial UKA.By reviewing and analyzing the causes,they established references for the early detection of risk factors for revision in clinical practice and for formulating surgical strategies and rehabilitation programmes.This commentary emphasizes the need for a meticulous understanding and an analysis of the revision rate following initial UKA and related management strategies.The implant rates,regional variation,and benefits of uncemented Oxford UKA have been explored,particularly in terms of bone preservation,appropriate surgical techniques,and weight management to control complications and improve patient prognosis.

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.

Current Trends in Clinical Practice for the Minimal Invasive Medial Unicondylar Knee Arthroplasty

Unicondylar Knee Arthroplasty (UKA) is an early alternative surgical procedure for the unicondylar osteoarthritis or damaged knee joint with artificial prosthesis for the release of disabling painful condition and restoring the normal knee functions. Minimally UKA is one of the recent and the majority successful procedures in modern orthopedics for the osteoarthritis which is spreading throughout the worldwide. Recently, many orthopedic surgeons are expanding their abilities in this field. However, it needs good knowledge and well experience for the successful clinical outcomes. The minimal invasive approach is more efficient for short hospital stay and faster postoperative recovery with low morbidity of the patients after UKA. The aim of this article is to emphasize the steps in UKA based on modern facts: function of knee joint, diagnosis, less invasive approach for medial condylar replacement, radiographic evaluation, and earlier recovery, selecting the patient and implant survivorship with review of surgery.

Influence of patellofemoral joint degeneration on clinical outcomes after medial unicompartmental knee arthroplasty

Background:Patellofemoral joint(PFJ)degeneration has traditionally been regarded as a contraindication to unicompartmental knee arthroplasty(UKA).More recently,some researchers have proposed that PFJ degeneration can be ignored in medial UKA,and others have proposed that this change should be reviewed in PFJ degenerative facets and severity.This study aimed to systematically evaluate the effect of PFJ degeneration on patient-reported outcome measures(PROMs)and revision rates after medial UKA.Methods:Electronic databases(PubMed,Embase,Web of Science,etc.)were searched for studies assessing the influence of PFJ degeneration on medial UKA.A random-effects meta-analysis was conducted for the Oxford knee score(OKS),Knee society score(KSS),and revision rates and stratified by PFJ degenerative facets(medial/lateral/trochlear/unspecified),severe PFJ degeneration(bone exposed),and bearing type(mobile/fixed).Heterogeneity was assessed by the Cochran Q test statistic and chi-squared tests with the I-squared statistic.Results:A total of 34 articles with 7007 knees(2267 with PFJ degeneration)were included(5762 mobile-bearing and 1145 fixed-bearing and 100 unspecified).Slight to moderate degenerative changes in the medial and trochlear facets did not decrease the OKS and KSS,and only lateral facets significantly decreased the OKS(mean difference[MD]=-2.18,P<0.01)and KSS(MD=-2.61,P<0.01).The severity degree of PFJ degeneration had no additional adverse effect on the OKS,KSS,or revision rates.For mobile-bearing UKA,only lateral PFJ degeneration significantly decreased the OKS(MD=-2.21,P<0.01)and KSS(MD=-2.44,P<0.01).For fixed-bearing UKA,no correlation was found between PROMs/revision rates and PFJ degeneration.Conclusion:For medial mobile-bearing UKA,slight to moderate degenerative changes in the PFJ,except lateral facet,did not compromise PROMs or revision rates.For medial fixed-bearing UKA,although it might not be conclusive enough,PROMs or revision rates were not adversely affected by PFJ degeneration(regardless of the facet).

Finite Element Analysis of Mobile-bearing Unicompartmental Knee Arthroplasty： The Influence of Tibial Component Coronal Alignment

Background： Controversies about the rational positioning of the tibial component in unicompartmental knee arthroplasty （UKA） still exist. Previous finite element （FE） studies were rare, and the results varied. This FE study aimed to analyze the influence of the tibial component coronal alignment on knee biomechanics in mobile-bearing UKA and find a ration range of inclination angles. Methods： A three-dimensional FE model of the intact knee was constructed from image data of one normal subject. A 1000 N compressive load was applied to the intact knee model for validating. Then a set of eleven UKA FE models was developed with the coronal inclination angles of the tibial tray ranging from 10° valgus to 10° varus. Tibial bone stresses and strains, contact pressures and load distribution in all UKA models were calculated and analyzed under the unified loading and boundary conditions. Results： Load distribution, contact pressures, and contact areas in intact knee model were validated. In UKA models, von Mises stress and compressive strain at proximal medial cortical bone increased significantly as the tibial tray was in valgus inclination 〉4°, which may increase the risk of residual pain. Compressive strains at tibial keel slot were above the high threshold with varus inclination 〉4°, which may result in greater risk of component migration. Tibial bone resection comer acted as a strain-raiser regardless of the inclination angles. Compressive strains at the resected surface slightly changed with the varying inclinations and were not supposed to induce bone resorption and component loosening. Contact pressures and load percentage in lateral compartment increased with the more varus inclination, which may lead to osteoarthritis progression. Conclusions： Static knee biomechanics after UKA can be greatly affected by tibial component coronal alignment. A rauge from 4° valgus to 4° varus inclination oftibial component can be recommended in mobile-bearing UKA.

Glycosaminoglycan Content of the Lateral Compartment Cartilage in Knees Conforming to the Indications for Oxford Medial Unicompartmental Knee Arthroplasty

Background： The quality of the lateral compartment cartilage is important to preoperative evaluation and prognostic prediction of unicompartmental knee arthroplasty （UKA）. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage （dGEMRIC） enables noninvasive assessment of glycosaminoglycan （GAG） content in cartilage. This study aimed to determine the GAG content of the lateral compartment cartilage in knees scheduled to undergo Oxford medial UKA. Methods： From December 2016 to May 2017, twenty patients （20 osteoarthritic knees） conforming to the indications fbr Oxford medial UKA were included as the osteoarthritis （OA） group, and 20 healthy volunteers （20 knees） paired by sex, knee side, age （±3 years）, and body mass index （BMI） （i3 kg/m2） were included as the control group. The GAG contents of the weight-bearing femoral cartilage （wbFC）, the posterior non-weight-bearing femoral cartilage （pFC）, the lateral femoral cartilage （FC）, and tibial cartilage （TC） were detected using dGEMRIC. The dGEMRIC indices （T1Gd） were calculated in the middle three consecutive slices of the lateral compartment. Paired t-tests were used to compare the T1Gd in each region of interest between the OA group and control group. Results： The average age and BMI in the two groups were similar. In the OA group, TIGd of FC and TC was 386.7 ± 50.7 ms and 429.6 ± 59.9 ins, respectively. In the control group, T1Gd of FC and TC was 397.5 ± 52.3 ms and 448.6 ±62.5 ms, respectively. The respective T 1Gd ofwbFC and pFC was 380.0 ± 47.8 ms and 391.0 ± 66.3 ms in the OA group and 400.3 ± 51.5 ms and 393.6 ± 57.9 ms in the control group. Although the T 1Gd ofwbFC and TC tended to be lower in the OA group than the control group, there was no significant difference between groups in the TIGd in any of the analyzed cartilage regions （P value ofwbFC, pFC, FC, and TC was 0.236, 0.857, 0.465, and 0.324, respectively）. Conclusions： The GAG content of the lateral compartment cartilage in knees confonning to indications for Oxford medial UKA is similar with those of age- and BMl-matched participants without OA.

Clinical Characteristics and Treatment of Spontaneous Osteonecrosis of Medial Tibial Plateau： A Retrospective Case Study

Background： In a small proportion of cases, spontaneous osteonecrosis of the knee （SONK） involves the medial tibial plateau （MT）. Here, we introduced the clinical characteristics of spontaneous osteonecrosis of the MT and unicompartmental knee arthroplasty （UKA） as the favorable treatment for this situation based on a retrospective case study. Methods： Patients with spontaneous osteonecrosis of the MT, confirmed by magnetic resonance imaging （MRI） at Guangdong Provincial Hospital of Chinese Medicine （China） from March 2015 to June 2016, were included as a case serial and analyzed retrospectively. All patients underwent Oxford Medial UKA. The characteristics of their lesions, corresponding treatment, and results of follow-up were presented. The lesion scores and grade were determined according to the criteria of Ficat and Arlet. Results： In total, 22 patients （5 men, 17 women： mean age, 64.1 years） with spontaneous osteonecrosis of the MT were analyzed. The lesion stages assessment showed that 3 （14%） were Stage 11, 10 （45%） were Stage Ⅲ, 7 （32%） were Stage IV, and 2 （9%） were Stage V. In the sagittal plane, 7 （32%） were in the anterior region （MTa） and 15 （68%） were central （MTc）. The lesion volume averaged 2.24 ± 0.79 cm3 （range： 1.57-3.08 cm3）. Seventeen patients （77%） had Level Ⅲ posterior medial meniscus root tears （MM RTs）. All the patients underwent UKA. Average follow-up was 30.0 ± 6.4 months with a range of 23.0-38.0 months. The visual analog scale score was 7.78 ± 0.67 belbre surgery while decreased to 2.22 ± 1.09 at the final follow-up （P 〈 0.001 ）. The Hospital for Special Surgery scores of pre-/post-surgery were 65.67 ± 5.45 and 84.10 ± 4.20, respectively （P 〈 0.001 ）. Conclusions： SONK often occurs in the anterior and central tibial plateau due to abnormal stresses. Most of the patients had Level Ⅲ posterior medial meniscus root tears. MRI is recommended for suspected cases to identity SONK at an early stage. The use of the Oxford Medial UKA for SONK of the MT is reliable both immediately and at follow-up.