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 short-term effectiveness of unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) in the treatment of medial compartment osteoarthritis (OA) of the knee so as to provide a reference for clinical selection of appropriate treatment.
MethodsBetween January 2010 and June 2011, 28 cases of medial compartment OA of the knee underwent UKA in 16 cases (UKA group) and HTO in 12 cases (HTO group). Biomet Oxford phase Ⅲ unicompartmental knee prosthesis was used in UKA group, and closing wedge osteotomy in HTO group. There was no significant difference in gender, age, course of disease, side, body mass index, articular cartilage degeneration classification, preoperative knee range of motion (ROM), Lysholm knee score, Tegner activity score, and femorotibial angle (FTA) between the 2 groups (P>0.05). The patients of UKA group began weight-bearing walking with walking aids within 48 hours after operation, and the patients of HTO group began weight-bearing walking with walking aids at 6 weeks after operation, and gradually began full weight-bearing walking at 8-12 weeks.
ResultsThere was no significant difference in operation time and intraoperative blood loss between 2 groups (t=0.406, P=0.688; t=-1.552, P=0.133). All incision healed primarily in both groups. No complications occurred in 2 groups. All patients were followed up 3.5 years on average (range, 3.0-4.5 years) in UKA group and 3.6 years on average (range, 3-4 years) in HTO group. There were significant differences in Lysholm knee score, Tegner activity score, and FTA in the 2 groups between before and after operation (P<0.05), but there was no significant difference in knee ROM (P>0.05). At last follow-up, there was no significant difference in all above indexes between 2 groups (P>0.05). The postoperative X-ray showed that all force lines of the lower limbs were corrected, and the prosthesis and internal fixation were fixed reliably. During follow-up, Kellgren-Lawrence Ⅱ degeneration of the lateral compartment was observed in 1 case of 2 groups respectively; Kellgren-Lawrence Ⅱ degeneration of the patellofemoral joint was observed in 1 case of the HTO group, there was no significant difference between the 2 groups (χ2=0.778, P=0.378).
ConclusionBoth UKA and HTO have good short-term effectiveness for treating unicompartmental OA; however, the long-term effectiveness need further study and follow-up.
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 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 evaluate the short-term effectiveness of unicompartmental knee arthroplasty (UKA) for medial compartmental osteoarthritis of the knee.
MethodsBetween January 2008 and October 2013, 18 patients with medial compartmental osteoarthritis of the knee were treated by UKA, including 11 males and 7 females with an average age of 67.2 years (range, 60-72 years). The disease duration ranged from 3 to 5 years (mean, 3.7 years). All patients had loading pain and walk-associated pain of the medial compartmental knee. The preoperative visual analogue scale (VAS) score was 6.8±1.4. The full-length radiograph of lower limb and anteroposterior and lateral radiographs of the knee showed medial compartmental osteoarthritis of the knee. According to Ahlback staging, 8 knees were at stageⅡand 10 knees at stageⅢ. The knee range of motion (ROM) was (112.3±11.3)°, and the angle of genu varus was (13.2±1.3)°. The American Hospital for Special Surgery (HSS) score was 59.0±6.4.
ResultsPrimary healing of incision was obtained in all patients, and no infection or lower limb deep venous thrombosis occurred. All of the patients were followed up 6-50 months (mean, 28 months). No prosthetic loosening and dislocation or lesions of contralateral compartment and patellofemoral joint developed. At 6 months after operation, the VAS score was significantly reduced to 2.8±1.2 (t=9.20, P=0.00); most of patients achieved significant relief of pain. The HSS score was significantly increased to 92.0±3.1 (t=19.69, P=0.00); and the results were excellent in 12 cases, good in 5 cases, and poor in 1 case, with an excellent and good rate of 94.4%. The knee ROM was (115.2±10.2)°, showing no significant difference when compared with preoperative one (t=-0.81, P=0.23). The alignment of limbs showed that the angle of genu varus was significantly reduced to (6.8±2.1)° (t=10.99, P=0.00).
ConclusionUKA has satisfactory short-term effectiveness in the treatment of medial compartmental knee osteoarthritis, however, long-term effectiveness need further studies.
【Abstract】 Objective To evaluate the mid-term effectiveness of Oxford Unicompartmental Knee system Phase III for medial unicompartmental knee osteoarthritis (OA). Methods Between December 2008 and August 2010, 26 patients (32 knees) with medial unicompartmental knee OA were treated. Of 26 patients, 11 were followed up more than 2 years, including 7 males and 4 females (14 knees, 6 left and 8 right knees) with an average age of 62.4 years (range, 50-74 years). All patients had load suffering and tenderness of medial unicompartmental knee, and complicated by varus deformity without limitation of flexion and extension; the disease duration ranged 5-23 years (mean, 11.6 years). According to Ahlback staging, 4 knees were at stage II and 10 knees at stage III. Cemented unicompartmental knee arthroplasty (Oxford Unicompartmental Knee system Phase III) was performed by minimally invasive technique. Results All the incisions were primary healing after operation. Five cases suffered from local ache in the pes anserinus during the first 3 months after operation, which was cured after conservative therapy. Of them, 11 patients were followed up 27.5 months on average (range, 24-30 months). During follow-up, no complication of prosthesis loosening, displacement, arthropathy in the opposite department, or the patellofemoral joint occurred. The range of motion was significantly improved from (109.2 ± 8.7)° preoperatively to (123.5 ± 6.7)° at last follow-up (P lt; 0.05); knee society score (KSS) and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scores were all significantly improved (P lt; 0.05). At last follow-up, the femoro-tibial angle was significantly improved (P lt; 0.05); tibial plateau and the tibial anatomical axis increased, showing no significant difference (P gt; 0.05); and posterior tibial slope was significantly decreased (P lt; 0.05). Conclusion Oxford Unicompartmental Knee system Phase III has satisfactory mid-term effectiveness in treating medial unicompartmental knee OA with the advantages of little trauma and rapid recovery, but long-term effectiveness is expected for further follow-up.
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.
The clinical performance and failure issues are significantly influenced by prosthetic malposition in unicompartmental knee arthroplasty (UKA). Uncertainty exists about the impact of the prosthetic joint line height in UKA on tibial insert wear. In this study, we combined the UKA musculoskeletal multibody dynamics model, finite element model and wear model to investigate the effects of seven joint line height cases of fixed UKA implant on postoperative insert contact mechanics, cumulative sliding distance, linear wear depth and volumetric wear. As the elevation of the joint line height in UKA, the medial contact force and the joint anterior-posterior translation during swing phase were increased, and further the maximum von Mises stress, contact stress, linear wear depth, cumulative sliding distance, and the volumetric wear also were increased. Furthermore, the wear area of the insert gradually shifted from the middle region to the rear. Compared to 0 mm joint line height, the maximum linear wear depth and volumetric wear were decreased by 7.9% and 6.8% at –2 mm joint line height, and by 23.7% and 20.6% at –6 mm joint line height, the maximum linear wear depth and volumetric wear increased by 10.7% and 5.9% at +2 mm joint line height, and by 24.1% and 35.7% at +6 mm joint line height, respectively. UKA prosthetic joint line installation errors can significantly affect the wear life of the polyethylene inserted articular surfaces. Therefore, it is conservatively recommended that clinicians limit intraoperative UKA joint line height errors to –2?+2 mm.
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 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.
