The surgical installation accuracy of the components in unicompartmental knee arthroplasty (UKA) is an important factor affecting the joint function and the implant life. Taking the ratio of the medial-lateral position of the femoral component relative to the tibial insert (a/A) as a parameter, and considering nine installation conditions of the femoral component, this study established the musculoskeletal multibody dynamics models of UKA to simulate the patients’ walking gait, and investigated the influences of the medial-lateral installation positions of the femoral component in UKA on the contact force, joint motion and ligament force of the knee joint. The results showed that, with the increase of a/A ratio, the medial contact force of the UKA implant was decreased and the lateral contact force of the cartilage was increased; the varus rotation, external rotation and posterior translation of the knee joint were increased; and the anterior cruciate ligament force, posterior cruciate ligament force and medial collateral ligament force were decreased. The medial-lateral installation positions of the femoral component in UKA had little effect on knee flexion-extension movement and lateral collateral ligament force. When the a/A ratio was less than or equalled to 0.375, the femoral component collided with the tibia. In order to prevent the overload on the medial implant and lateral cartilage, the excessive ligament force, and the collision between the femoral component and the tibia, it is suggested that the a/A ratio should be controlled within the range of 0.427−0.688 when the femoral component is installed in UKA. This study provides a reference for the accurate installation of the femoral component in UKA.
ObjectiveTo compare the effectiveness of unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) in the treatment of severe medial compartment osteoarthritis (OA).MethodsA clinical data of 69 patients (69 knees), who underwent joint replacement due to severe medial compartment OA between February 2015 and September 2018 and met the selection criteria, was retrospectively analyzed. Among them, 38 cases were treated with UKA (UKA group) and 31 cases with TKA (TKA group). There was no significant difference in gender, age, body mass index, course of disease, lesion side, and preoperative visual analogue scale (VAS) score, Hospital for Special Surgery (HSS) score, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score, Feller score, range of motion of knee, physiological and psychological scores of short-form 12 health survey scale (SF-12) between the two groups (P>0.05). The femorotibial angle (FTA) of TKA group was bigger than that of UKA group, and hip-knee-ankle angle (HKA) was smaller, showing significant differences (P<0.05). The operative time, incision length, blood loss, time for flexion 90°, ambulation time, hospital stay, and incidence of deep venous thrombosis of lower extremity were recorded and compared between the two groups. The VAS score, HSS score, WOMAC score, Feller score, range of motion, and physiological and psychological scores of SF-12 were used to evaluate patients’ quality of life. FTA, HKA, and prosthesis looseness were observed by X-ray films. Kaplan-Merier survival analysis was used to evaluate the survival rate of prosthesis.ResultsAll operations were successfully completed in both groups. Compared with TKA group, UKA group had shorter incision length, longer operative time, and less blood loss (P<0.05). There was no significant difference in time for flexion 90°, ambulation time, hospital stay, and the incidence of deep venous thrombosis of lower extremity between the two groups (P>0.05). The incisions in both groups healed by first intention. During follow-up, 3 patients in the UKA group and 1 patient in the TKA group developed mild anterior knee pain. Patients were followed up (30.7±9.6) months in the UKA group and (34.9±8.7) months in the TKA group, and the difference was not significant (t=–1.832, P=0.071). At last follow-up, there were significant differences in the HSS score, Feller score, WOMAC score, range of motion, VAS score, and physiological and psychological scores of SF-12 between pre- and post-operation (P<0.05). The range of motion in the UKA group was bigger than that in the TKA group (Z=–2.666, P=0.008), and there was no significant difference in the other indexes between the two groups (P>0.05). X-ray films showed that the alignment of the two groups recovered well, and the FTA and HKA of the two groups were improved at 1 week after operation (P<0.05). No radiolucency was found around the prosthesis during follow-up, no prosthesis loosening and meniscal bearing dislocation occurred. The survival rates of the prostheses in the two groups were 100%.ConclusionFor severe medial compartment OA, the early survival rates of the two prostheses are similar, but UKA has less traumatic, can preserve the normal structure of the knee, and the range of motion of the knee after operation is significantly better than TKA.
ObjectiveTo evaluate the effectiveness of Oxford mobile-bearing bipolar prosthesis unicompartmental knee arthroplasty (UKA) in the treatment of single compartmental knee osteoarthritis. MethodsBetween June 2011 and July 2013, 22 cases of single compartmental knee osteoarthritis were treated by Oxford mobile-bearing bipolar prosthesis UKA. Of 22 cases, 8 were male and 14 were female with an average age of 65 years (range, 45-80 years); the left knee was involved in 12 cases, and the right knee in 10 cases, with a mean disease duration of 32.5 months (range, 8-90 months). The mean weight was 55.2 kg (range, 50-65 kg), and the mean body mass index was 20.8 kg/m2(range, 17-25 kg/m2). Osteoarthritis involved in the single knee medial compartment in all patients. Knee society score (KSS) and range of motion (ROM) were measured to evaluate the knee joint function. ResultsPrimary healing of incision was obtained in all patients, and there was no complication of infection, bedsore, or deep venous thrombosis. Postoperative follow-up was 2-4 years (mean, 3.2 years). The X-ray films showed good position of prosthesis, no prosthesis dislocation, or periprosthetic infection during follow-up. Knee ROM, KSS function score, and KSS clinical score were significantly improved at 1 week after operation and at last follow-up when compared with preoperative ones (P＜0.05), but no significant difference was shown between at 1 week and at last follow-up (P>0.05). ConclusionOxford mobile-bearing bipolar prosthesis UKA is an effective method to treat single compartmental knee osteoarthritis, with the advantages of less trauma, earlier rehabilitation exercise, near physiological state in joint function, and less risk of complications.
ObjectiveTo investigate the short-term effectiveness of unicompartmental knee arthroplasty (UKA) in the treatment of knee osteoarthritis of super-age patients over 85 years old.MethodsSenile patients with unilateral compartment osteoarthritis of the knee who received UKA between November 2013 and May 2017 and met the inclusion criteria were enrolled as the research objects. Among them, 40 patients (50 knees) were more than 85 years old (super-age group) and 44 patients (50 knees) were 52-81 years old (control group). There was significant difference in age between the two groups (t=17.33, P=0.00). There was no significant difference in body mass index, degenerative classification of medial and lateral compartments, varus deformity of knee, disease duration, complicating diseases, and preoperative hemoglobin, hematocrit (HCT), American Hospital for Special Surgery (HSS) score, range of motion (ROM) of knee, visual analogue scale (VAS) score, and femoral-tibial angle (FTA) between the two groups (P>0.05). Hospital stay, hemoglobin, and HCT of the two groups were recorded before operation and on the first day after operation. The changes of hemoglobin and HCT after operation were calculated. During follow-up period, the ROM of the knee, HSS score, and VAS score were measured; the position of the prosthesis and FTA were observed by X-ray films.ResultsThere was no significant difference in hospital stay between the two groups (t=1.05, P=0.29). Hemoglobin and HCT of the two groups on the first day after operation were significantly lower than those before operation (P<0.05). There was no significant difference in the postoperative changes of hemoglobin and HCT between the two groups (P>0.05). All the patients were followed up completely except 4 cases (5 knees) in the super-age group. The follow-up time ranged from 14 to 44 months of super-age group (mean, 29 months) and 21 to 33 months of control group (mean, 24 months). There were significant differences in HSS score, VAS score, ROM of the knee, and FTA between pre-operation and last follow-up in the two groups (P<0.05). There was significant difference in HSS score between the two groups (P<0.05), and no significant difference was found in ROM, VAS score, and FTA between the two groups (P>0.05). X-ray film showed no adverse position of the prosthesis, infection around the prosthesis, prosthesis loosening, or pathological bright lines.ConclusionUKA combined with reasonable perioperative management in the treatment of super-age patients over 85 years with knee osteoarthritis is safe and feasible, and can obtain satisfactory short-term effectiveness.
ObjectiveTo summarize research progress of change in bone mineral density (BMD) after knee arthroplasty and its diagnostic methods, influencing factors, and drug prevention and treatment.MethodsThe relevant literature at home and abroad was reviewed and summarized from research status of the advantages and disadvantages of BMD assessment methods, the trend of changes in BMD after knee arthroplasty and its influencing factors, and the differences in effectiveness of drugs.ResultsThe central BMD and mean BMD around the prosthesis decrease after knee arthroplasty, which is closely associated with body position, age, weight, daily activities, and the fixation methods, design, and material of prosthesis. Denosumab, bisphosphonates, and teriparatide et al. can decrease BMD loss after knee arthroplasty.ConclusionBMD after knee arthroplasty decreases, which is related to various factors, but the mechanism is unclear. At present, some inhibitors of bone resorption can decrease BMD loss after knee arthroplasty. However, its long-term efficacy remains to be further explored.
ObjectiveTo summarize the clinical application and research progress in unicompartmental knee arthroplasty (UKA).MethodsThe literature related to UKA in recent years was reviewed and the emerging indications, implant options, comparisons between other surgical techniques, and recent advances were summarized.ResultsClinical studies show that UKA has many advantages, such as less trauma, faster recovery, and fewer postoperative complications. At present, the operative indication has been expanded. The body mass index more than 25 kg/m2, less than 60 years old, patellofemoral arthritis, and anterior cruciate ligament dysfunction are no longer considered as contraindications. The prosthesis type in UKA should be selected according to the patient’s condition. In recent years, the robot-assisted UKA can effectively improve the effectiveness, improve patient satisfaction, and reduce postoperative complications.ConclusionWith the development of surgical techniques, designs of prosthesis, and the robotic technology, UKA would be further applicated. As more long-term data on UKA become available, it will further guide clinicians in counseling patients on whether UKA should be performed.
ObjectivesTo systematically review the efficacy of unicompartmental knee arthroplasty on forgotten joint score (FJS) in patients with knee osteoarthritis.MethodsPubMed, EMbase, The Cochrane Library, Web of Science, CNKI, CBM, WanFang Data and VIP databases were electronically searched to collect randomized controlled trials (RCTs) and cohort studies on unicompartmental knee arthroplasty on FJS in patients with knee osteoarthritis from inception to December 31st, 2019. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 2 RCTs and 11 cohort studies were included. The results of meta-analysis based on RCTs showed that: compared to posterior stabilized total knee arthroplasty (PS-TKA), unicompartmental knee arthroplasty could improve FJS on 12-month (MD=9.23, 95%CI 0.53 to 17.93, P=0.04) after operation. The results of meta-analysis based on cohort studies showed that: compared to PS-TKA, unicompartmental knee arthroplasty could improve FJS on 6-week (MD=8.90, 95%CI 6.87 to 10.94, P<0.000 01), 6-month (MD=18.72, 95%CI 8.71 to 28.74, P=0.000 2), 1-year after operation (MD=13.41, 95%CI 8.87 to 17.95, P<0.000 01), and the last follow-up (MD=0.99, 95%CI 0.47 to 1.54, P=0.000 2).ConclusionsCurrent evidence shows that, comparing with PS-TKA, unicompartmental knee arthroplasty in knee osteoarthritis shows advantage in the improvement of FJS. Due to limited quality and quantity of the included studies, more high-quality studies are required to verify above conclusions.
ObjectiveTo compare the short-term effectiveness of medial unicompartmental knee arthroplasty (UKA) between patients younger or older than 60 years of age, and to investigate the impact of age on the effectiveness. Methods The clinical data of 182 patients (182 knees) who underwent medial UKA between July 2016 and June 2018 were retrospectively analyzed, of which 72 patients were less than 60 years old (group A) and 110 patients were more than 60 years old (group B). There was a significant difference in age between groups (t=−20.198, P<0.001). No significant difference was found in gender, body mass index, surgical sides, Kellgren-Lawrence grading, disease duration, and preoperative Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score between groups (P>0.05). The postoperative hospital stay and complications were recorded, and the WOMAC score, satisfaction score, and prosthesis revision were compared between groups. Results The length of postoperative hospital stay was (4.50±1.09) days in group A, and (4.46±1.29) days in group B, with no significant difference between groups (t=0.198, P=0.844). All incisions healed by first intention. The incidences of early postoperative complications in groups A and B were 5.6% and 3.6%, respectively, and the difference was not significant (χ2=0.061, P=0.804). All patients were followed up. The follow-up time were 28-50 months (mean, 36 months) in group A and 28-50 months (mean, 35 months) in group B. At last follow-up, the WOMAC scores of both groups significantly improved when compared with those before operation (P<0.05), and there was no significant difference between groups (P>0.05) in the difference before and after operation. The satisfaction scores were 6.6±1.7 in group A and 6.9±1.6 in group B, with no significant difference between groups (t=−1.326, P=0.186). There was no revision surgery in both groups during follow-up period. ConclusionAge has no significant effect on the prognosis of medial UKA, and patients younger than 60 years of age can also obtain good short-term effectiveness.
Objective To summarize the computer assisted navigation and robotics in the classification of knee surgery, and the development, surgical indications and contraindication, effectiveness, and the research progress of computer assisted navigation and robotics in unicompartmental knee arthroplasty (UKA). Methods The related literature on computer assisted navigation and robotics in UKA was extensively reviewed, summarized, and analyzed. Results Recently, satisfactory results have been achieved in UKA for the treatment of single compartmental knee osteoarthritis. With the rapid development of computer navigation and robotic technology gradually combined with clinical practice, the great precision and accuracy of implant have been improved in computer navigation and robotics in UKA surgery. Postoperative function is well recovered, meanwhile, prosthesis survival can be significantly increased. Conclusion Computer assisted navigation and robotics in UKA can greatly improve the accuracy of the implant when compared with traditional UKA. The early effectiveness is satisfactory, but the long-term effectiveness still needs to be further observed.
ObjectiveTo summarize the priority and indications of the unicompartmental knee arthroplasty (UKA) and the evolution of minimally invasive surgery-UKA (MIS-UKA), and to discuss the effectiveness. MethodsThe related literature on UKA was extensively reviewed, summarized, and analyzed. ResultsRecently, satisfactory results has been achieved in UKA for the treatment of single room knee osteoarthritis. Both the design of the single condyle prosthesis and the surgical technique are becoming more advanced, which make the MIS-UKA possible. Especially the application of navigation computer and robot assisted system on UKA improves the accuracy of unicompartmental prosthesis implantation greatly. ConclusionThe superiority and indications of MIS-UKA are gradually expanding with the progress of surgical technique and the design of the single condyle prosthesis. However, whether the application of navigation computer and robot assisted system can improve the effectiveness needs to be further confirmed.