Peroneal intraneural ganglia: The importance of the articular branch. A unifying theory

Object. Based on a large multicenter experience and a review of the literature, the authors propose a unifying theory to explain an articular origin of peroneal intraneural ganglia. They believe that this unifying theory explains certain intriguing, but poorly understood findings in the literature, including the proximity of the cyst to the joint, the unusual preferential deep peroneal nerve (DPN) deficit, the absence of a pure superficial peroneal nerve (SPN) involvement, the finding of a pedicle in 40% of cases, and the high (10-20%) recurrence rate. Methods. The authors believe that peroneal intraneural lesions are derived from the superior tibiofibular joint and communicate from it via a one-way valve. Given access to the articular branch, the cyst typically dissects proximally by the path of least resistance within the epineurium and up the DPN and the DPN component of the common peroneal nerve (CPN) before compressing nearby SPN fascicles. The authors present objective evidence based on anatomical, clinical, imaging, operative, and histological data that support this unifying theory. Conclusions. The predictable clinical presentation, electrical studies, imaging characteristics, operative observations, and histological findings regarding peroneal intraneural ganglia can be understood in terms of their origin from the superior tibiofibular joint, the anatomy of the articular branch, and the internal topography of the peroneal nerve that the cyst invades. Understanding the controversial pathogenesis of these cysts will enable surgeons to perform operations based on the pathoanatomy of the articular branch of the CPN and the superior tibiofibular joint, which will ultimately improve clinical results.