IV.

The aim of this up-to-date meta-analysis was to compare the effects of surgical versus non-surgical treatment of patients following primary patellar dislocation and to provide the best evidence currently available. A comprehensive literature search was conducted using multiple databases, including Medline, Embase, and Cochrane Registry of Clinical Trials. All databases were searched from the earliest records to May 2013. Eligible studies were selected, and data were extracted by two independent investigators. The primary outcome variable was the frequency of recurrent patellar dislocation. The other outcomes included knee function scores, patient-rated outcomes, and radiographic examination. If appropriate, meta-analysis of these variables was performed. Nine independent trials were found to match the inclusion criteria. The pooled results demonstrated that the incidence of recurrent patellar dislocation and Hughston visual analog scale was significantly lower in the surgical treatment group than that in the non-surgical treatment group (P < 0.05). There was no statistically significant difference between the two treatment groups in frequency of subsequent surgical interventions, percentage of excellent or good subjective opinion, Kujala score, pain score on visual analog scale, and severity of patellofemoral joint osteoarthrosis (P > 0.05). This up-to-date meta-analysis indicates that surgical treatment was associated with a lower risk of recurrent patellar dislocation, but a lower Hughston VAS than non-surgical treatment for primary patellar dislocation. More large high-quality trials and further studies are needed to overcome the limitations of small sample sizes, and varieties of different surgical procedures or non-surgical management strategies adopted in the included trials.

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Preconditioning of the grafts prior to implantation into the knee is considered to reduce the loss of tension caused by graft viscoelasticity after anterior cruciate ligament reconstruction. The present study analyzed the impacts of different preconditioning forces on the biomechanical properties of the γ-irradiated deep frozen tendon allografts. A total of 36 tendon grafts were randomly divided into three groups and were preconditioned at 80 N (group 1), 160 N (group 2) and 320 N (group 3) for 10 min. Subsequently, the grafts were gradually completely relaxed for 1 min and subsequently received 25 cyclic loads of 0–80 N. Afterwards, the grafts were loaded to 80 N, which was maintained for 30 min. Finally, load was gradually increased until ultimate failure at maximum load (UFML) was obtained. There were significant differences in the stiffness and UFML values between the 3 groups (all P<0.05). The graft stiffness in group 3 significantly increased compared with the other 2 groups, and the stiffness of group 2 grafts increased compared with group 1. The UFML in group 3 was significantly lower compared with groups 1 and 2, while there was no significant difference between groups 1 and 2. In the present study, the results suggested that increasing the initial tension could effectively reduce the loss of stiffness due to viscoelasticity for the γ-irradiated deep frozen allogeneic tendon grafts. However, overloaded initial tension decreased the tensile strength.