Assessing the relationship of the peroneal nerve to the posterolateral corner of the knee and influence of race on its dimensions– A MRI based study in Indian population

Abstract

Background: The relationship of Common peroneal nerve (CPN) to the posterolateral corner of the knee joint is important for surgeons who perform total knee arthroplasty to avoid injury to the nerve during surgery. This relationship varies among different races on account of anthropometry. This study aims to evaluate the anatomical location of this nerve in Indian patients using an MRI based reference system. Methods: 213 knee magnetic resonance images (MRIs) were evaluated in axial plane 8 mm below the joint line for distance of the CPN from the closest posterolateral capsule. The angle of the CPN from the center of the tibial anteroposterior axis and relation of CPN with respect to the popliteus were evaluated. A comparative analysis of these measurements among Caucasian, Chinese and Indian patients was made to evaluate for any differences. Results: The mean distance between the CPN and the knee capsule was 15.55 mm (range, 7.8e26.2 mm). The mean angle of the CPN from the center of the AP axis was 50.1 (range, 38e63). CPN was found to be in line with the popliteus from center of the knee in 62% cases. There was no significant difference among the different races among the measured parameters (p > 0.005). Conclusion: This study establishes a "danger zone" and a "safe zone" to avoid CPN injury in total knee arthroplasty in Indian patients and identifies anatomic landmarks to localize the nerve before the softtissues release in order to avoid direct injury.

Influence and Clinical Significance of Knee Flexion Angle on the Anatomic Course of the Common Peroneal Nerve in the Posterolateral Corner of the Knee Joint

“…These values are very close to the measurements obtained in other studies. 5,8,25 However, previous studies on the anatomic relationship between The CPN could not be detected at the joint-line level when the knee was flexed to 90°.…”

Incidence, Injury Mechanisms, and Recovery of Iatrogenic Nerve Injuries During Hip and Knee Arthroplasty

“…3 Injury to the CPN is the most common motor nerve injury after TKA, and it is the most studied. 7,22,[34][35][36] The most common proposed mechanisms are stretch from leg lengthening or retractor placement and injury during a posterolateral corner release (Figure 8). Stretch injury seems to be a risk especially when doing a TKA in a patient with a valgus deformity, a flexion contracture, or a combined valgus deformity with a flexion contracture.…”

“…The location of the CPN is 7.8 to 26.2 mm from the capsule, regardless of the amount of deformity. 34,35 The incidence of CPN injury has been reported to be between 0.3% and 4.3%. 7,36 Treatment of this complication includes observation, loosening of constricting bandages, and flexing the knee.…”

“…37 Multiple studies have evaluated the safety of the Ranawat inside-out release of the posterolateral structures. 34,35 During this portion of TKA balancing, a scalpel, an electrocautery, or needle is used to “pie-crust” the tight lateral structures in a valgus knee. The location of the CPN is 7.8 to 26.2 mm from the capsule, regardless of the amount of deformity.…”

“…The location of the CPN is 7.8 to 26.2 mm from the capsule, regardless of the amount of deformity. 34,35…”