Objective To evaluate the strength of polyethylene l inercement interface when cementing a new linerinto a fixed acetabular cup in revision. Methods Twenty-five pairs of metal acetabular cups with polyethylene l iners were randomly divided into 5 groups: 1 group with standard locking device as control group (group A), other l iners were cemented into acetabular cups as 4 experimental groups. According to different intersection angles of metal acetabular cups with polyethylene liners and the polyethylene l iners with or without metal ball, the 4 experimental groups were no ball 0° group (group B), 0° group (group C), 10° group (group D), and 20° group (group E), metal acetabular cups intersected with polyethylene liners without metal ball in group B, with metal ball in groups C, D, and E, respectively. The lever-out biomechanical test reproduced in vivo failure mechanism was then performed to evaluate the lever-out failure strength of l iner-cement-metalcup interface. Results The values of l iver-out failure force were (626.68 ± 206.12), (915.04 ± 197.49), (449.02 ± 119.78),(814.68 ± 53.89), and (1 033.05 ± 226.44) N in groups A, B, C, D, and E, respectively, showing significant differences forcomparison among groups (F=8.989，P=0.000). The values of l iver-out failure force in groups B and E were significantlyhigher than that in group A (P lt; 0.05), but no significant difference was found between groups C, D and group A (P gt; 0.05).Conclusion Cementation of polyethylene l iner into a malposition shell meeting within 20° can provide enough fixed strength.
ObjectiveTo evaluate the effectiveness of cemented polyethylene liner technique in hip revision.MethodsBased on inclusion criteria, the clinical data of 26 patients who were undergone hip revision between January 2011 and December 2013, were retrospectively reviewed. Among them, 14 cases were treated with isolated liner exchange (group A) and 12 cases were treated with cemented polyethylene liner technique (group B). There was no significant difference in gender, age, the time from primary total hip arthroplasty to revision, and the preoperative Harris score between 2 groups (P>0.05). The post-operative Harris score and complications were compared between 2 groups, and X-ray findings of the hip joint were recorded to review the position of hip components.ResultsAll patients were followed up 4.4-6.4 years (mean, 5.4 years). Except for two femoral fractures during the revision (1 in each group), there was no other complication in 2 groups. The hip pain relieved and the lame gait corrected in 2 groups. The hip’s function of 2 groups improved gradually after operation, with a better Harris score at 3 months and the best at last follow-up, compared with preoperative scores (P<0.05). There was no significant difference in Harris score at difference time points after operation between 2 group (P>0.05). X-ray films showed no dislocation, aseptic loosening, and other interface related complication.ConclusionFor the cases without the chance to do change liner, cemented polyethylene liner technique has a good effectiveness. But restrict patient selection should be considered before hip revision.
ObjectiveTo investigate the effect of body mass index (BMI) on the short- and medium-term effectiveness of unicompartmental knee arthroplasty (UKA) in the treatment of anterior medial compartmental osteoarthritis of knee joint.MethodsThe clinical data of 55 patients (61 knees) with anterior medial compartmental osteoarthritis of knee joint treated with minimally invasive UKA between May 2014 and May 2019 were retrospectively analyzed. According to BMI, the patients were divided into 3 groups: normal body mass group [group A, BMI 18.50-24.99 kg/m2, 23 cases (25 knees)], overweight group [group B, BMI 25.00-29.99 kg/m2, 23 cases (25 knees)], obesity group [group C, BMI 30.00-39.99 kg/m2, 9 cases (11 knees)]. There was no significant difference in gender, age, sides, disease duration, and preoperative American Special Surgery Hospital (HSS) score, pain visual analogue scale (VAS) score, and knee range of motion (ROM) among 3 groups (P>0.05). The operation time, intraoperative dominant blood loss, and the postoperative decreased amount of hemoglobin at 1 week were recorded and compared among 3 groups. The HSS score, VAS score, and ROM were used to evaluate the knee function and pain improvement.ResultsThere was no significant difference in the operation time, the intraoperative dominant blood loss, and the postoperative decreased amount of hemoglobin at 1 week among 3 groups (P>0.05). All the 55 patients were followed up 5-60 months, with an average of 24 months. No complication such as infection, fat embolism, or deep venous thrombosis of lower extremity occurred after operation. The anteroposterior and lateral X-ray films of the knee joint showed that no dislocation or loosening of the prosthesis occurred and the position of the prosthesis was good. At last follow-up, the HSS score, VAS score, and ROM of the 3 groups were significantly improved when compared with preoperative ones (P<0.05); but there was no significant difference among 3 groups (P>0.05).ConclusionFor obese and overweight patients with anterior medial compartmental osteoarthritis of the knee joint, the use of minimally invasive UKA can achieve satisfactory short- and medium-term effectiveness, and the long-term effectiveness needs further follow-up.
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.