Origin and insertion of the medial patellofemoral ligament: a systematic review of anatomy.

PURPOSE: The medial patellofemoral ligament (MPFL) is the major medial soft-tissue stabiliser of the patella, originating from the medial femoral condyle and inserting onto the medial patella. The exact position reported in the literature varies. Understanding the true anatomical origin and insertion of the MPFL is critical to successful reconstruction. The purpose of this systematic review was to determine these locations. METHODS: A systematic search of published (AMED, CINAHL, MEDLINE, EMBASE, PubMed and Cochrane Library) and unpublished literature databases was conducted from their inception to the 3 February 2016. All papers investigating the anatomy of the MPFL were eligible. Methodological quality was assessed using a modified CASP tool. A narrative analysis approach was adopted to synthesise the findings. RESULTS: After screening and review of 2045 papers, a total of 67 studies investigating the relevant anatomy were included. From this, the origin appears to be from an area rather than (as previously reported) a single point on the medial femoral condyle. The weighted average length was 56 mm with an 'hourglass' shape, fanning out at both ligament ends. CONCLUSION: The MPFL is an hourglass-shaped structure running from a triangular space between the adductor tubercle, medial femoral epicondyle and gastrocnemius tubercle and inserts onto the superomedial aspect of the patella. Awareness of anatomy is critical for assessment, anatomical repair and successful surgical patellar stabilisation. LEVEL OF EVIDENCE: Systematic review of anatomical dissections and imaging studies, Level IV

More than a reposition tool: additional wire cerclage leads to increased load to failure in plate osteosynthesis for supracondylar femoral shaft fractures

INTRODUCTION: Surgical treatment of supracondylar femoral fractures can be challenging. An additional wire cerclage is a suggested way to facilitate fracture reduction prior to plate osteosynthesis. Denudation to the periosteum remains a problematic disadvantage of this procedure. This study analyzed the effect of an additional wire cerclage on the load to failure in plate osteosynthesis of oblique supracondylar femoral shaft fractures. MATERIALS AND METHODS: On eight pairs of non-osteoporotic human femora (mean age 74 years; range 57–95 years), an unstable AO/OTA 32-A2.3 fracture was established. All specimens were treated with a polyaxially locking plate. One femur of each pair was randomly selected to receive an additional fracture fixation with a wire cerclage. A servohydraulic testing machine was used to perform an incremental cyclic axial load with a load to the failure mode. RESULTS: Specimens stabilized with solely plate osteosynthesis failed at a mean load of 2450 N (95% CI: 1996–2904 N). In the group with an additional wire cerclage, load to failure was at a mean of 3100 N (95% CI: 2662–3538 N) (p = 0.018). Compression deformation with shearing of the condyle region through cutting of screws out of the condylar bone was the most common reason for failure in both groups of specimens. Whereas axial stiffness was comparable between both groups (p = 0.208), plastic deformation of the osteosynthesis constructs differed significantly (p = 0.035). CONCLUSIONS: An additional wire cerclage significantly increased the load to failure. Therefore, an additional cerclage represents more than just a repositioning aid. With appropriate fracture morphology, a cerclage can significantly improve the strength of the osteosynthesis

Emerging themes in SecA2-mediated protein export

The conserved general secretion (Sec) pathway carries out most protein export in bacteria and is powered by the essential SecA ATPase. Interestingly, mycobacteria and some Gram positive bacteria possess two SecA proteins: SecA1 and SecA2. In these species, SecA1 is responsible for exporting the majority of proteins whereas SecA2 exports only a subset of substrates and is implicated in virulence. However, despite the impressive body of knowledge on the canonical SecA (SecA1), less is known concerning SecA2 function. Here, we review our current understanding of the different types of SecA2 systems and outline future directions for SecA2 studies