Objective To conclude the research progress of unicompartmental knee arthroplasty (UKA) in the treatment of elderly patients with knee osteoarthritis (KOA). Methods The literature on UKA at home and abroad in recent years was reviewed to summarize the clinical characteristics of elderly patients with KOA, perioperative management (including evaluating indications preoperatively, intraoperative prosthesis selection, postoperative complication management, etc). Results Through reasonable preoperative evaluation, prosthesis selection, and advanced perioperative management, for elderly patients with KOA who meet the indications, UKA can be considered. Compared with total knee arthroplasty, the incidence of postoperative complications in elderly patients undergoing UKA is lower, joint awareness is reduced, functional improvement and satisfaction are higher. Meanwhile, choosing appropriate prostheses and fixation methods can lead to a good survival rate. ConclusionUKA can provide a safe and effective treatment option for elderly patients with KOA within a certain range of indications.
ObjectiveTo conclude the revision reason of unicompartmental knee arthroplasty (UKA) using computer-assisted technology so as to provide reference for reducing the revision incidence and improving the level of surgical technique and rehabilitation. MethodThe relevant literature on analyzing revision reason of UKA using computer-assisted technology in recent years was extensively reviewed. ResultsThe revision reasons by computer-assisted technology are fracture of the medial tibial plateau, progressive osteoarthritis of reserved compartment, dislocation of mobile bearing, prosthesis loosening, polyethylene wear, and unexplained persistent pain. ConclusionsComputer-assisted technology can be used to analyze the revision reason of UKA and guide the best operating method and rehabilitation scheme by simulating the operative process and knee joint activities.
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.
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 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.
ObjectiveTo explore the short- and mid-term effectivenesses of combined unicompartmental knee arthroplasty (UKA) and anterior cruciate ligament (ACL) reconstruction for osteoarthritis (OA) and ACL injury. MethodsBetween January 2006 and January 2014, 32 patients with knee OA and ACL injury were treated by combined UKA and ACL reconstruction. There were 12 males and 20 females, aged 41-63 years (mean, 50 years); 17 left knees and 15 right knees were involved. The causes of ACL injury were sports injury (25 cases) and traffic accident injury (7 cases), including 27 cases of old injury and 5 cases of acute injury. Pain of the medial compartment of the knee and unstable knee joint were the main clinical symptoms. Preoperative X-ray films showed (3.1±0.6)° of varus deformity. ResultsAll incisions healed by first intention, without complication. The patients were followed up 16-112 months (mean, 55 months). Mobile bearing dislocation occurred in 2 cases after operation, and was cured after replacing much thicker mobile bearings. X-ray films showed (4.0±0.7)° of valgus at last follow-up. There was no loosening of the prosthesis. Physiological radiolucent line (<1 mm) was observed around the tibial component in 10 patients. The Oxford Knee Score (OKS), Knee Society Score (KSS) clinical score, KSS functional score, and Tegner activity score at last follow-up were improved significantly (P<0.05). The range of motion (ROM) of the operated knee was (123.5±2.8)°, and the posterior slope of the tibial component was (3.9±1.2)° at last follow-up; a significant correlation was found between ROM and posterior slope according to the Pearson's correlation (r=0.392, P=0.031). ConclusionCombined UKA and ACL reconstruction has good short- and mid-term effectivenesses for OA and ACL injury.
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.
ObjectiveA prospective randomized controlled study was conducted to investigate the early postoperative analgesic effectiveness of using liposomal bupivacaine (LB) for local infiltration anesthesia (LIA) in unicompartmental knee arthroplasty (UKA). Methods Between January 2024 and July 2024, a total of 80 patients with knee osteoarthritis (KOA) who met the selection criteria were enrolled in the study. Patients were randomly assigned to either the LB group or the “cocktail” group in a 1∶1 ratio using a random number table, with 40 patients in each group. Baseline characteristics, including gender, age, body mass index, operated side, Kellgren-Lawrence grade, and preoperative American Society of Anesthesiologists (ASA) classification, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and knee joint range of motion, showed no significant difference between the two groups (P>0.05). Both groups received LIA and comprehensive pain management. The surgical duration, incision length, pain-related indicators [resting and activity visual analogue scale (VAS) scores, total dosage of oral morphine, WOMAC scores], knee joint range of motion, first ambulation time after operation, length of hospital stay, and postoperative adverse events. ResultsThere was no significant difference between the two groups in surgical duration, incision length, first ambulation time after operation, length of hospital stay, total dosage of oral morphine, and pre-discharge satisfaction with surgery and WOMAC scores (P>0.05). At 4, 12, and 24 hours after operation, the resting and activity VAS scores in the “cocktail” group were lower than those in the LB group; at 60 and 72 hours postoperatively, the resting VAS scores in the LB group were lower than those in the “cocktail” group, with the activity VAS scores also being lower at 60 hours; all showing significant differences (P<0.05). There was no significant difference in the above indicators between the two groups at other time points (P>0.05). On the second postoperative day, the sleep scores of the LB group were significantly higher than those of the “cocktail” group (P<0.05), while there was no significant difference in sleep scores on the day of surgery and the first postoperative day (P>0.05). Additionally, the incidence of complications showed no significant difference between the two groups (P>0.05). ConclusionThe use of LB for LIA in UKA can provide prolonged postoperative pain relief; however, it does not demonstrate a significant advantage over the “cocktail” method in terms of short-term analgesic effects or reducing opioid consumption and early functional recovery after UKA. Nevertheless, LB may help reduce postoperative sleep disturbances, making it a recommended option for UKA patients with cardiovascular diseases and insomnia or other mental health issues.
ObjectiveTo compare the early effectiveness and safety of simultaneous bilateral and staged bilateral unicompartmental knee arthroplasty (UKA) in treatment of anteromedial compartment osteoarthritis.MethodsThe clinical data of 31 patients with bilateral anteromedial compartment osteoarthritis who underwent bilateral UKAs between January 2015 and January 2017 was retrospectively analyzed. Of them, 17 patients were treated with simultaneous bilateral UKAs (simultaneous group) and 14 patients with staged bilateral UKAs (staged group). There was no significant difference in gender, age, body mass index, osteoarthritis grading, and preoperative hip-knee-ankle angle, knee society score (KSS), visual analogue scale (VAS) score, and range of motion (ROM) of knee between the two groups (P>0.05). The operation time, blood loss, hospitalization stay, minimum hemoglobin value during 10 days after operation, and hospitalization cost were recorded. The staged group was compared by the sum of two operations. The effectiveness was evaluated by KSS score, VAS score, ROM at 3, 6, 12 months after operation, and patient satisfaction scores were recorded at 12 months after operation.ResultsThe operation time, hospitalization stay, and hospitalization cost of the simultaneous group were significantly lower than those of the staged group (P<0.05). There was no significant difference in blood loss and the minimum hemoglobin value during 10 days after operation between the two groups (P>0.05). Superficial infection occurred in 1 side of 1 case (7.1%) in staged group. Postoperative delirium occurred in 1 case (5.9%) in simultaneous group. There was no significant difference in incidence of postoperative complications between the two groups (P=1.000). Patients in both groups were followed up 12-32 months (mean, 24.7 months). There was no significant difference in KSS score between the two groups at 3 months after operation (t=0.896, P=0.392). KSS scores were significanly higher in simultaneous group than in staged group at 6 and 12 months after operation (P<0.05). There was no significant difference in ROM and VAS scores between the two groups at 3, 6, and 12 months after operation (P>0.05). At 12 months after operation, the patient satisfaction scores were significantly higher in simultaneous group than in staged group (P<0.05). X-ray films showed no loosening of the prosthesis in the two groups.ConclusionSimultaneous bilateral UKAs has the same security as staged bilateral UKAs. Meanwhile knee function recovery was better, hospitalization stay and hospitalization cost reduced, and patient satisfaction was higher in simultaneous bilateral UKAs.
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.