Treatment for Periprosthetic Cyst after Total Hip Arthroplasty: Analysis of Six Cases.

The present study investigates the pathogenesis of periprosthetic cysts after total hip replacement, and explores appropriate treatment appoaches. Six patients with periprosthetic cysts after total hip arthroplasty were treated at the First Affiliated Hospital of Nanjing Medical University between 2009 and 2014. During surgery, it was found that all cysts communicated with the hip and the hip prosthesis could be seen after cyst excision. Four patients simply underwent cyst excision, and light red liquid was found in the cyst. Among them, radiological examination revealed that a part of the hip prosthesis projected from the bone bed in one case. Postoperative pathology revealed a synovial cyst with inflammatory cell infiltration. Prostheses were loosened in two cases, so cystectomy and revision of the prosthesis were performed at the same time. Among the six patients, polyethylene wear particles could be seen in five patients through a pathological polarizing microscope. Out of the four patients who underwent simple cyst excision, two patients experienced cyst recurrence within 1 year after surgery; however, there was no cyst recurrence in the two patients who underwent cyst excision and revision of the prosthesis. The formation of a periprosthetic cyst after hip replacement is likely to be related to polyethylene wear and undesirable prosthesis position; in addition, when treated by simple cyst excision, the rate of recurrence was higher.

MRI measurement on intercondylar notch after anterior cruciate ligament rupture and its correlation.

The knee joint is extremely susceptible to injury, which is usually identified by magnetic resonance imaging (MRI). In the present study, MRI was applied to quantitatively detect the association between anterior cruciate ligament (ACL) rupture and anatomic morphologic changes of the intercondylar notch. Forty patients with unilateral ACL rupture who were treated between July, 2013 and October, 2014 were enrolled in the present study. The patients were divided into the observation (affected side) and control (healthy side) groups. MRI measurements were undertaken based on parameters associated with intercondylar notch of double knee joints. The results showed that intercondylar notch width (ICW) in the observation group was significantly smaller than that in the control group, and differences were statistically significant (P<0.05). Differences on the intercondylar notch height and femoral condyle width [epicondylar width (EW)] between the two groups were not statistically significant (P>0.05). Notch width index (NWI) and notch shape index (NSI) in the observation group were significantly less than those in the control group and differences were statistically significant (P<0.05). Differences of Lysholm and Tegner scoring between the two groups were not statistically significant (P>0.05). The differential value of ICW in the observation group was 2.6±1.3 mm and the ACL rupture time of the affected knee was 20.4±1.3 months on average. The correlation was statistically significant (P<0.05). The correlation of Lysholm scoring, Tegner scoring and intercondylar notch stenosis degree on the affected knee was not statistically significant (P>0.05). In conclusion, after ACL rupture, ICW on the affected knee had significant stenosis, NSI and NWI were significantly reduced and the stenosis degree was aggravated with the prolongation of course. By contrast, Lysholm and Tegner scoring of patients with different degrees of stenosis had no correlation.

Establishment of a rat model for osteoarthritis resulting from anterior cruciate ligament rupture and its significance.

The purpose of this study was to examine the establishment of a model concerned with osteoarthritis resulting from the anterior cruciate ligament rupture of rats and investigate the associated mechanism, as well as provide a theoretical basis for clinical treatment of the disease. Forty Sprague-Dawley male rats were randomly divided into two groups of 20 rats each and the anterior cruciate ligament transaction model and knee joint brake model were successfully established. Two rats in the anterior cruciate ligament transection group (10%) and 3 rats in the knee joint brake group (15.0%) died. The survival rate of the two groups was not statistically significant (χ2<0.001, P=1.000). Swelling of the knee joint and synovium of rats in the two experimental groups was aggravated. The Mankin score was significantly higher in the anterior cruciate ligament transection group than that in the experimental group and the difference was statistically significant (P<0.05). By contrast, no significant difference was observed for osteoarthritis severity for the two experimental groups (P>0.05). Analysis of the subgroups showed that the proportion of the anterior cruciate ligament in the experimental group was significantly higher than that of the knee joint brake group, and the difference was statistically significant (P<0.05). By contrast, the difference was not statistically significant in the comparison of the medium and early proportion (P>0.05). The content of protein polysaccharide and II collagen fiber in the experimental group of the anterior cruciate ligament transection was lower than that of the knee joint brake group, and this difference was statistically significant (P<0.05). Thus the mechanism of osteoarthritis may be associated with the decrease in the content of protein and II collagen fibers.