Published online Dec 18, 2021. doi: 10.5312/wjo.v12.i12.1008
Peer-review started: April 1, 2021
First decision: July 28, 2021
Revised: August 11, 2021
Accepted: December 7, 2021
Article in press: December 7, 2021
Published online: December 18, 2021
Processing time: 256 Days and 10.8 Hours
Development of infrapatellar saphenous neuroma (ISN) is a well-recognized source of knee pain after total knee arthroplasty (TKA).
So far, very few studies have addressed the issue of the development of painful ISN after TKA, and no clear evidence regarding its importance on functional outcome and patient satisfaction exists.
The current clinical study aims to evaluate the results of surgical treatment of ISN after primary TKA, the level of pain relief, and the improvement of knee motion and function.
This study is a clinical series of 15 patients (13 women, 2 men) with persistent pain for more than six months after primary TKA due to osteoarthritis, who underwent surgical excision of ISN. Active knee range of motion (ROM), visual analog scale (VAS) for pain, Knee Society Score (KSS) for pain and function were evaluated before and at least 6 mo after neuroma excision, with a mean follow-up of 8 mo (range: 6 to 11 mo).
The mean patients’ age was 71.3 ± 5.4 years old. The mean interval between TKA and neuroma excision was 10 mo (range, 6 to 14 mo). All patients experienced almost immediate and complete pain relief and resolution of allodynia and hyperesthesia after surgery. Mean pain relief in terms of VAS exceeded the MCID for adequate pain control (mean difference -7.8 ± 1.9, P = 0.001). Only two patients reported some residual numbness that gradually resolved during the time but didn’t cause any functional deficit. The KSS pain and function scores were significantly improved from 49.3 ± 5.9 and 62.7 ± 12.8 before surgery to 91.8 ± 4.2 and 75.3 ± 11.3 after surgery, respectively (P = 0.001 and P = 0.015). Active knee ROM was also increased postoperatively from 96 ± 4 to 105 ± 6 degrees (P = 0.001). There were no complications and no further operations required
Iatrogenic injury of IPSN may cause persistent pain after TKA in an otherwise non-infected, well-fixed, and well-aligned prosthetic joint. Neuroma excision can provide excellent pain relief and improve the knee function and range of motion.
Further clinical studies are required to identify the predisposing factors for development of traumatic ISN during TKA as well as the optimal treatment approach of postoperative neurogenic pain around the knee joint area.