High-Resolution Ultrasonography of Minor Nerves Around the Knee

Presentation Format: Oral presentation.

Purpose or Learning Objective: To describe the potential role of high-resolution ultrasonography (US) for the evaluation of submillimetric nerve branches around the knee.

Methods or Background: US-guided percutaneous latex injections were performed in three cadaveric specimens to identify the course of the infrapatellar (InBSN) of the saphenous and motor branch to the vastus medialis (VMN); the terminal branches of the obturator (tON), the geniculate nerves (GeN), the recurrent (ReCPN), retinacular (RetPN), and articular branches (ArPN) of the peroneal; and the distal branches of the anterior (AFCN) and posterior femoral cutaneous (PFCN) and determine whether US is able to localize these small nerves. A consecutive series of 18 patients who had selective sensory and/or motor disturbances in the area of the distribution of these nerves were examined with US using 24–8 MHz matrix and 22–8 MHz hockey-stick probes.

Results or Findings: Cadaveric dissection confirmed that US was able to guide latex stain correctly into and around the InBSN, VMN, tON, GeN, ReCPN, RetPN, ArPN, AFCN, and PCNF in all specimens. US allowed detection of definite nerve abnormalities in 11 of 18 cases. Pathologic findings included five fusiform neuromas and/or fibrous encasement, two schwannomas, one neurofibroma, and three intraneural ganglion cysts.

Conclusion: High-resolution US can identify small minor nerves around the knee and characterize their abnormalities, providing unique information about these tiny branches. Injury of small sensitive nerves detected by means of high-resolution US may explain sensory disturbances and pain around the knee in patients with no other identified knee conditions.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
03 June 2021