The os peroneum syndrome (sometimes termed painful os peroneum syndrome (POPS)) refers to a wide spectrum of conditions associated with an os peroneum at the lateral aspect of the foot. It can result in tenosynovitis and/or discontinuity of the peroneus longus tendon.
It can include one of more of the following:
- acute os peroneum fracture or diastasis of a multipartite os peroneum
- chronic (healing or healed) os peroneum fracture or diastasis of a multipartite os peroneum with callus formation which can result in stenosing peroneus longus tenosynovitis
- attrition or partial rupture of the peroneus longus tendon, proximal or distal to the os peroneum
- frank rupture of the peroneus longus tendon with discontinuity proximal or distal to the os peroneum
- presence of a large peroneal tubercle on the lateral aspect of the calcaneus which entraps the peroneus longus tendon and/or the os peroneum during tendon excursion.
Swelling over the cuboid
Pain over the cuboid during palpation.
Pain exacerbated by plantar flexion of 1st ray and heel elevation stage during gait
• Best visualized on oblique view
• Contralateral foot X-Ray can help differentiate between bipartite normal variant and acute fracture
• Acute fracture – non sclerotic and jagged edges
• Bipartite normal variant – sclerotic and rounded edges
• Diastasis greater than 5mm indicates fracture
• Displacement of the os peroneum is an indirect sign of a peroneal tendon rupture and MRI should be ordered MRI:
• Increased intrasubstantial signal within the peroneus longus tendon, typically close to the cuboid
• Acute fracture or os peroneum or rupture of peroneus longus can be identified
• Initial treatment for minimally displaced fracture or painful os perineum include : Immobilization, Restricted weightbearing, Rest, NSAIDS
• After failure of conservative care, simple excision is advised for painful os peroneum if minimal tendon involvement is identified
• Primary repair was preferred if at least 50% of the tendon remained after debridement, and tendon transfer if <50% of the tendon remained after debridement.