Lateral plantar fasciopathy: An frequently overlooked cause of atraumatic pain at the fifth metatarsal base

Background

Lateral cord plantar fasciitis (LCPF) causes atraumatic pain at the fifth metatarsal base. This study assesses the outcomes of a conservative treatment (PRP + casting) on LCPF.

Methods

Medical history, clinical diagnosis, and ultrasound imaging were used to determine LPCF. All patients received a leucocyte-poor PRP injection at the proximal part of the fifth metatarsal base, followed by three weeks in a walking cast. Follow-up questionnaires, encompassing NRS, AOFAS, and Foot Functioning Index (FFI), were administered at 6 weeks, 12 weeks, and 2 years post-treatment.

Results

Ten patients were enrolled in the study. Ultrasound findings revealed hyposonant and thickened lateral fascia plantaris at the MT 5 insertion point with normal peronei tendons. There was a notable reduction in pain from pre-treatment (NRS_rest 55.1 ± 29.6, NRS_activity 79.20 ± 15.5) to 6 weeks post-treatment (NRS_rest: 22.4 ± 23.6, p = 0.03; NRS_activity: 38.6 ± 30.3, p = 0.005). FFI indicated an improvement between 12 weeks (25.7 ± 25.7) and 2 years (9.1 ± 8.5) compared to pre-treatment (42.6 ± 16.7).

Conclusion

Ultrasound stands out as the preferred diagnostic method for identifying LCPF. A PRP injection followed by a walking cast proves effective in relieving LCPF symptoms within six weeks with sustained relief up to two years.

Level of evidence

Level IV