ObjectiveTo explore the imaging features of intramedullary guide rod and its influence on the alignment of the femoral prosthesis in unicompartmental knee arthroplasty (UKA). MethodsBetween August 2016 and November 2016, 50 patients (50 knees) with primary anteromedial osteoarthritis were treated with UKA by Oxford MicroPlasty minimally invasive replacement system. There were 10 males and 40 females. The age ranged from 62 to 77 years with an average of 68.8 years. Preoperative varus and flexion deformity angles were (5.22±3.46)° and (7.42±2.65)°, respectively. The knee range of motion (ROM) was (106.85±7.62)°. The Hospital for Special Surgery (HSS) score was 68.26±4.65. The angles between the femoral intramedullary guide rod and the anatomical axis of femur on the coronal and sagittal planes, the femoral component valgus/varus angle (FCVA), the femoral component posterior slope angle (FCPSA), knee varus deformity angle, and knee flexion deformity angle were measured by intra- and post-operative X-ray films. The postoperative ROM and HSS score were measured. ResultsIntraoperative X-ray films measurement showed that the lateral side angles between femoral intramedullary guide rod and femoral anatomical axis were observed on coronal plane, and the angles ranged from 0.28 to 2.06° with an average of 0.96°. While the posterior side angles were observed on sagittal plane, and the angles ranged from 0.09 to 0.48° with an average of 0.23°. The angulations (>1°) between femoral intramedullary part guide rod and outside part of the rod were confirmed in 12 cases (24%) on coronal plane. Postoperative femoral prosthesis were mild varus in 38 patients (76%). The FCVA ranged from –1.76 to 4.08° with an average of 2.21°. The FCPSA ranged from 7.12 to 13.86° with an average of 9.16°. All patients were followed up 22-26 months, with an average of 24.5 months. The incisions healed by first intention. At last follow-up, the varus and flexion deformity angles were (1.82±1.05) and (2.54 ± 1.86)°, respectively. ROM was (124.62±5.85)° and HSS score was 91.58±3.65. There were significant differences between pre- and post-operative parameters (P<0.05). No complication such as dislocation or aseptic loosening of the prosthesis occurred during the follow-up. ConclusionUKA by Oxford MicroPlasty minimally invasive replacement system can obtain accurate femoral prosthesis position with the help of intramedullary guide system, and the effectiveness is excellent.
ObjectiveTo explore the feasibility and short-term effectiveness of lateral unicompartmental knee arthroplasty (LUKA) through a lateral parapatellar approach for lateral compartmental osteoarthritis (LCOA). MethodsBetween November 2010 and August 2012, 15 consecutive patients (15 knees) with LCOA were treated with LUKA. There were 7 men and 8 women with a mean age of 67.3 years (range, 51-82 years). The mean duration of disease was 5.4 years (range, 3-15 years). The left knee was involved in 6 cases and the right knee in 9 cases. According to Ahlback rating, there were 2 cases (2 knees) of grade I, 8 cases (8 knees) of grade Ⅱ, and 5 cases (5 knees) of grade Ⅲ. The incision length, operation time, blood loss, drainage, and complication were recorded. The pre- and post-operative knee function was evaluated by Hospital for Special Surgery (HSS) score system. The pre- and post-operative range of motion (ROM) and alignment of the lower limbs (hip-knee-ankle angle) were measured and compared. ResultsACL rupture or medial compartmental osteoarthritis occurred in 2 patients (2 knees) who changed to total knee arthroplasty (TKA); 1 case (1 knee) failed to follow up. The other 12 cases (12 knees) were followed up 32.5 months on average (range, 26- 45 months). The mean length of incision was 6.9 cm (range, 6-8 cm); the mean operation time was 115.8 minutes (range,90-155 minutes); the mean blood loss volume during operation was 152.2 mL (range, 105-250 mL); and mean drainage was 145.6 mL (range, 50-300 mL). At last follow-up, the average HSS score was significantly improved from 73.4±4.6 preoperatively to 94.6±2.1 postoperatively (t=14.240, P=0.000). The results were excellent in 9 cases, good in 2 cases, and fair in 1 case, with an excellent and good rate of 91.7%. The hip-knee-ankle angle was significantly decreased from valgus angle of (10.08±1.38)° preoperatively to valgus angle of (5.17±0.94)° postoperatively (t=14.626, P=0.000). Postoperative ROM was significantly improved to (123.75±4.09)° from (108.67±5.10)° preoperatively (t=8.998, P=0.000). Two patients developed superficial skin infection, which was managed with anti-inflammatory therapy and dressing. No patient had complication of deep vein thrombosis, prosthesis dislocation and loosing, or development of medial osteoarthritis. ConclusionLUKA through a lateral approach has the advantages of rapid recovery of joint function, less complication, and small trauma in the treatment of LCOA. Correct patient selection and further mid- and long-term studies, however, are essential.
Objective To analyze the accuracy of prosthesis size selection in Naton robot-assisted medial unicondyle knee arthroplasty by comparing the actual prosthesis size used during operation and the preoperative planning. Methods The clinical data of 100 patients (110 knees) who underwent Naton robot-assisted medial unicondylar knee arthroplasty between June 2023 and July 2024 was retrospectively analyzed, including 47 knees on left side and 63 knees on right side. There were 37 males (40 knees) and 63 females (70 knees) with a mean age of 65.4 years (range, 59-71 years). Body mass index was 22.2-28.6 kg/m2 (mean, 25.4 kg/m2). The disease duration ranged from 1 to 8 years (mean, 3.4 years). Preoperative planning was performed by Naton robotic surgical system based on lower limb CT data. The final prosthesis size after osteotomy was recorded and compared with the preoperative plan to analyse whether it was consistent with the preoperative plan, as well as the situation of knee flexion and extension gaps (<0.5 mm, >2.0 mm) corresponding to the different models of prostheses. ResultsDuring operation, 5 patients (5 knees) were treated with traditional UKA due to mechanical arm failure, software obstacles, significant bone amputation bias, or loose reference frame, and were excluded from the final analysis. The remaining 95 patients (105 knees) successfully received Naton robot-assisted surgery, and no related complications occurred. The prosthesis size was consistent with the preoperative plan in 101 knees (96.2%) on the femur side, 100 knees (95.2%) on the tibia side, and 97 knees (92.4%) on both femur and tibia sides. The prosthesis size was inconsistent in 3 cases (2.86%) on the femur side alone, 4 cases (3.81%) on the tibial side alone, and 1 case (0.95%) on both femur and tibial sides. Among the prostheses with different models, the flexion and extension gaps were less than 0.5 mm in 3 knees, the flexion gap was less than 0.5 mm and the extension gap was more than 2.0 mm in 3 knees, and the flexion gap was more than 2.0 mm and the extension gap was less than 0.5 mm in 2 knees. Conclusion The accuracy of prosthesis size selection for Naton robot-assisted medial unicondylar knee arthroplasty is relatively high.
Objective To investigate the effect of Navio robot-assisted unicompartmental knee arthroplasty (UKA) on the biomechanics of knee joint during sitting-up movement, and to determine whether UKA can maintain the biomechanical characteristics of knee joint. Methods The clinical data of 8 patients with medial compartment osteoarthritis treated with medial fixed platform of Navio robot-assisted UKA between January 2018 and January 2019 and had the complete follow-up data were retrospectively analyzed. There were 4 males and 4 females; the age ranged from 58 to 67 years, with an average of 62.3 years. The disease duration was 6-18 months, with an average of 13 months. The varus deformity ranged from 4° to 6°, with an average of 5°; the knee flexion range of motion was 0°-130°, with an average of 110°. All patients had no extension limitation. The imaging data of bilateral knees during sitting-up movement were collected by biplane C-arm X-ray machine at 3 weeks before operation and 7 months after operation. The three-dimensional models of femur and tibia were established by dual-energy CT scanning, and the three-dimensional models of femur and tibia were matched and synchronized with the femur and tibia in X-ray film by automatic matching tracer software. The biomechanical parameters of femur and tibia were measured, including internal rotation/external rotation, varus/valgus, forward/backward displacement of medial and lateral tibia contact center, and lateral compartment joint space. Results Eight patients were followed up 5-7 months, with an average of 6.4 months. In the comparison of the affected side before and after operation, except for the difference of varus/valgus which was significant (t=4.959, P=0.002), the differences in other indicators was not significant (P>0.05). There were significant differences in varus/valgus and internal rotation/external rotation between healthy and affected sides at 3 weeks before operation (P<0.05), and the differences in other indicators was not significant (P>0.05). At 7 months after operation, the difference in the forward and backward displacement of medial tibia contact center was significant (t=3.798, P=0.007), and the differences in other indicators was not significant (P>0.05). Conclusion UKA can effectively correct the varus and valgus of the knee joint, and restore the rotational biomechanical characteristics of the affected knee joint. It does not affect the establishment of the lateral compartment joint space, but the medial and lateral tibia contact center still changes.
ObjectiveTo explore whether unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) or bilateral TKAs should be performed in patients with bilateral knee osteoarthritis.MethodsBetween April 2015 and February 2017, 24 patients with bilateral knee osteoarthritis who met the selection criteria were included in the study and randomly divided into 2 groups (n=12). The patients in observation group were treated with TKA of the multicompartmental osteoarthritis knee in the first-stage operation and UKA of the unicompartmental osteoarthritis knee in the second-stage operation; and the patients in control group were treated with bilateral TKAs in staging operation. The operation time, the amount of postoperative drainage, and the time of active flexion of the knee joint at 90° were recorded. The difference of hemoglobin (Hb) before and after the second-stage operation was recorded, and the decrease of Hb was observed. The hospital stay after the second-stage operation was observed. The Hospital for Special Surgery (HSS) score, visual analogue scale (VAS) score, and range of motion (ROM) were recorded at 7 days after the first-stage operation, and at 15 days, 45 days, and 6 months after the second-stage operation. At 1 year after the second-stage operation, the mean values of the above indexes of both knees were taken as the individual comprehensive evaluation. The X-ray films were taken regularly to examine the prosthesis and lower extremity force line. ResultsThe incisions in both groups were healed by first intention after two stage operations. The differences in the operation time, the amount of postoperative drainage, and the time of active flexion of the knee joint at 90° between the two groups were not significant in the first-stage operation (P>0.05) and were significant in the second-stage operation (P<0.05). The decrease of Hb and hospital stay after the second-stage operation were significantly lower in observation group than in control group (P<0.05). Both groups were followed up, the follow-up time was 12-18 months (mean, 14 months) in observation group and 12-21 months (mean, 16 months) in control group. During the follow-up period, X-ray films showed that the prosthesis positions of both sides were normal as well as the alignment line, and no infection, loosening or dislocation of prosthesis occurred. There was no significant difference in HSS score, VAS score, and ROM of multicompartmental osteoarthritis knee at 7 days after the first-stage operation between the two groups (P>0.05), indicating that the two groups were still comparable. The HSS score, VAS score, and ROM of unicompartmental osteoarthritis knee in observation group were superior to control group (P<0.05) after the second-stage operation. At 1 year, the HSS score, VAS score, and ROM in observation group were also superior to control group (P<0.05).ConclusionOn the premise of strict indications, the patients with bilateral knee osteoarthritis should be treated according to their own pathological changes in order to obtain better short-term effectiveness.
Objective To investigate the influence of tibial component posterior slope angle (TCPSA) on the short- and mid-term effectiveness of unicompartmental knee arthroplasty (UKA). MethodsThe clinical data of the patients with anterior medial knee osteoarthritis (KOA) treated by UKA between May 2014 and May 2019 were retrospectively analysed. There were 10 males and 45 females with a median age of 68 years (range, 49-83 years). The body mass index (BMI) was 27.63-52.26 kg/m2, with an average of 40.04 kg/m2. There were 28 cases of left knee, 21 cases of right knee, and 6 cases of double knees. The disease duration was from 7 months to 12 years, with an average of 4.33 years. Measurements of posterior tibial slope (PTS) and TCPSA were performed on the knee joint X-ray films of patients before operation and at last follow-up, respectively. According to the postoperative TCPSA, patients were divided into TCPSA<4° group (group A), 4°≤TCPSA<9° group (group B), and TCPSA>9° group (group C) with the quartile method. Baseline data such as age, gender, BMI, and affected side were compared among the 3 groups, as well as the Hospital for Special Surgery (HSS) score, visual analogue scale (VAS) score, and range of motion (ROM) before and after operation. ResultsAll 55 patients were followed up 17-72 months, with an average of 36 months. No complication such as prosthesis loosening, infection, tibial plateau collapse, and dislocation of the meniscus pad occurred. The preoperative PTS was (7.38±3.37)°, and the postoperative TCPSA was (6.25±3.22)°, showing no significant difference (t=1.815, P=0.074). According to postoperative TCPSA, there were 12 knees in group A, 32 in group B, and 17 in group C. There was no significant difference in age, gender, BMI, affected side, and preoperative HSS scores, ROM, and VAS scores among the 3 groups (P>0.05). At last follow-up, the HSS scores, ROM, and VAS scores of the 3 groups significantly improved when compared with preoperative ones (P<0.05). There was no significant difference in the difference of the above indicators before and after operation among 3 groups (P>0.05). ConclusionThe patients with anterior medial KOA may have good short- and mid-term effectiveness after UKA. Among the recommended range of TCPSA, there is no significant influence on the postoperative short- and mid-term effectiveness. Long-term effectiveness need to extend the follow-up time and expand the sample size for research verification.
Objective To investigate the short- and mid-term effectiveness of unicompartmental knee arthroplasty (UKA) for post-traumatic arthritis (PTA) of knee. Methods The clinical data of 30 patients with PTA of unilateral knee between March 2014 and September 2021 was retrospectively analyzed. There were 14 males and 16 females with an average of 64.5 years (range, 33-81 years). The average body mass index was 26.7 kg/m2 (range, 19.8-35.6 kg/m2). The types of injuries that caused PTA included intra-articular fracture in 16 cases, extra-articular fracture in 8 cases, and soft tissue injury in 6 cases. The initial injuries were treated by conservative therapy in 12 cases and by surgical therapy in 18 cases. Ten cases were medial compartment osteoarthritis and 20 cases were lateral compartment osteoarthritis. According to Kellgren-Lawrence staging, there were 19 cases of grade Ⅲ and 11 cases of grade Ⅳ. The operative time, the length of hospital stay, complications, and subjective satisfaction were recorded. The Oxford Knee Function Score (OKS), Hospital for Special Surgery (HSS) score, and knee range of motion (ROM) were used to evaluate knee function. Weight-bearing X-ray films were taken to measure the femoro-tibial angle (FTA) and to assess alignment correction of the lower limb. Results The operative time ranged from 50 to 95 minutes (mean, 63.7 minutes), the length of hospital stay ranged from 3 to 8 days (mean, 6.9 days). Superficial infection occurred in 2 patients, while the remaining incisions healed by first intention. There was no deep vein thrombosis or neurovascular injury. All patients were followed up 17-109 months (median, 70 months). At last follow-up, OKS score, HSS score, and ROM in 30 cases significantly improved when compared with those before operation (P<0.05). Lower limb alignment was significantly corrected and there was significant difference in FTA of the varus and valgus knees between pre- and post-operation (P<0.05). The patient satisfaction rate was 86.7% (26/30). Two cases developed contralateral osteoarthritis progression during follow-up. No bearing dislocation, prosthesis loosening or sinking occurred and none required further revision. Conclusion For patients with PTA of knee, UKA can obtain definite short- and mid-term effectiveness with high patient satisfaction.
ObjectiveTo investigate the surgical technique and the short-term effectivenss of lateral unicompartmental knee arthroplasty (LUKA) through lateral approach in the treatment of valgus knee and to calculate the maximum value of the theoretical correction of knee valgus deformity. MethodsA retrospective analysis was performed on 16 patients (20 knees) who underwent LUKA and met the selection criteria between April 2021 and July 2022. There were 2 males and 14 females, aged 57-85 years (mean, 71.5 years). The disease duration ranged from 1 to 18 years, with an average of 11.9 years. Knee valgus was staged according to Ranawat classification, there were 6 knees of type Ⅰ, 13 knees of type Ⅱ, and 1 knee of type Ⅲ. All patients were assigned the expected correction value of genu valgus deformity by preoperative planning, including the correction value of lateral approach, intra-articular correction value, and residual knee valgus deformity value. The actual postoperative corrected values of the above indicators were recorded and the theoretical maximum correctable knee valgus deformity values were extrapolated. The operation time, intraoperative blood loss, incision length, hospital stay, hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibia angle (mMPTA), joint line convergence angle (JLCA), posterior tibial slope (PTS), range of motion (ROM), Hospital for Special Surgery (HSS) score, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score were also recorded for effectiveness evaluation. Results The patients’ incision length averaged 13.83 cm, operation time averaged 85.8 minutes, intraoperative blood loss averaged 74.9 mL, and hospital stay averaged 6.7 days. None of the patients suffered any significant intraoperative neurological or vascular injuries. All patients were followed up 10-27 months, with a mean of 17.9 months. One patient with bilateral knee valgus deformities had intra-articular infection in the left knee at 1 month after operation and the remaining patients had no complication such as prosthesis loosening, dislocation, and infection. The ROM, HSS score, and WOMAC score of knee joint significantly improved at each time point after operation when compared to those before operation, and the indicators further improved with time after operation, the differences were all significant (P<0.05). Imaging measurement showed that HKA, mLDFA, JLCA, and PTS significantly improved at 3 days after operation (P<0.05) except for mMPTA (P>0.05). Postoperative evaluation of the knee valgus deformity correction values showed that the actual intra-articular correction values ranged from 0.54° to 10.97°, with a mean of 3.84°. The postoperative residual knee valgus deformity values ranged from 0.42° to 5.30°, with a mean of 3.59°. The actual correction values of lateral approach ranged from 0.21° to 12.73°, with a mean of 4.26°. ConclusionLUKA through lateral approach for knee valgus deformity can achieve good early effectiveness. Preoperative planning can help surgeons rationally allocate the correction value of knee valgus deformity, provide corresponding treatment strategies, and the maximum theoretical correction value of knee valgus deformity can reach 25°.
ObjectiveTo investigate the effect of anterior cruciate ligament (ACL) integrity on the short- and mid-term effectiveness of mobile-bearing medial unicompartmental knee arthroplasty (UKA). MethodsThe 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. ResultsAll 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). ConclusionThe integrity of ACL has no significant effect on the short- and mid-term effectiveness of mobile-bearing medial UKA.
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. MethodsA 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. ResultsBased 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. ConclusionOxford 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.