High-resolution MRI using a microscopy coil for the diagnosis of recurrent lateral patellar dislocation

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A systematic search of published (AMED, CINAHL, MEDLINE, EMBASE, PubMed and Cochrane Library) and unpublished literature databases was conducted from their inception to the 3 February 2016.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.

Evaluation of the chondromalacia patella using a microscopy coil: comparison of the two-dimensional fast spin echo techniques and the three-dimensional fast field echo techniques

OBJECTIVE

We wanted to compare the two-dimensional (2D) fast spin echo (FSE) techniques and the three-dimensional (3D) fast field echo techniques for the evaluation of the chondromalacia patella using a microscopy coil.

MATERIALS AND METHODS

Twenty five patients who underwent total knee arthroplasty were included in this study. Preoperative MRI evaluation of the patella was performed using a microscopy coil (47 mm). The proton density-weighted fast spin echo images (PD), the fat-suppressed PD images (FS-PD), the intermediate weighted-fat suppressed fast spin echo images (iw-FS-FSE), the 3D balanced-fast field echo images (B-FFE), the 3D water selective cartilage scan (WATS-c) and the 3D water selective fluid scan (WATS-f) were obtained on a 1.5T MRI scanner. The patellar cartilage was evaluated in nine areas: the superior, middle and the inferior portions that were subdivided into the medial, central and lateral facets in a total of 215 areas. Employing the Noyes grading system, the MRI grade 0-I, II and III lesions were compared using the gross and microscopic findings. The sensitivity, specificity and accuracy were evaluated for each sequence. The significance of the differences for the individual sequences was calculated using the McNemar test.

RESULTS

The gross and microscopic findings demonstrated 167 grade 0-I lesions, 40 grade II lesions and eight grade III lesions. Iw-FS-FSE had the highest accuracy (sensitivity/specificity/accuracy = 88%/98%/96%), followed by FS-PD (78%/98%/93%, respectively), PD (76%/98%/93%, respectively), B-FFE (71%/100%/93%, respectively), WATS-c (67%/100%/92%, respectively) and WATS-f (58%/99%/89%, respectively). There were statistically significant differences for the iw-FS-FSE and WATS-f and for the PD-FS and WATS-f (p < 0.01).

CONCLUSION

The iw-FS-FSE images obtained with a microscopy coil show best diagnostic performance among the 2D and 3D GRE images for evaluating the chondromalacia patella.

An analysis of the medial patellofemoral ligament length change pattern using open-MRI

Recently, for a recurrent patellar dislocation, medial patellofemoral ligament (MPFL) reconstruction has come to be commonly performed, yet the precise in vivo MPFL biomechanics still remains to be clarified. The purpose of this study was to analyze the length change pattern of MPFL in vivo. The subjects were comprised of ten male and ten female healthy volunteers. The length of the MPFL was measured using an open-MRI both from a leg extended position and a highly knee-flexed position in order to analyze the length change pattern of the MPFL. The MPFL length for men and women resulted in an average of 52 ± 3 mm and 43 ± 2 mm at the knee extended position, respectively. The length change pattern of the MPFL presented a slight change at up to a flexion angle of 60° and a decrease at over 60°. In terms of morphology, the fiber bundle of the MPFL experienced linear tension at a knee flexion angle of 60°. We determined that the MPFL length in vivo exhibited a specific length change pattern. MPFL mainly contributes to the medial constraint of a patella with a knee flexion of 0° to 60°, wherein it is expected to have the strongest strain at 60°. However, more studies are needed to obtain a better understanding of cases with a history of patellar dislocation.