There is a strong need for the development of core outcome sets (COS) across nerve surgery to allow for improved data synthesis, meta-analyses, and reporting consistency. Development of a core outcome set typically starts with assessing the literature for previously reported outcome measures. Common peroneal neuropathy (CPN) is the most common compressive mononeuropathy of the lower extremity and can result in pain, motor, and sensory deficits. A COS for COmmon PEroneal neuropathy (COS-COPE) is needed to improve future study design and comparison and synthesis of data. The goal of the current study was to assess the literature for outcomes reported in studies on CPN as the first step in the development of a COS.
A systematic review of the literature from 2000 to 2023 was performed utilizing PubMed and Medical Subject Headings (MeSH). Identified articles were screened according to study inclusion/exclusion criteria. Outcome measures reported in each included study were recorded and categorized into motor, sensory, pain, composite foot/ankle score, electrodiagnostics, function/disability patient-reported outcome (PRO), psychological, or other outcomes. Descriptive statistics were performed.
A total of 31 articles met criteria for inclusion. A motor outcome was reported in 26 (83.9%) studies; 12 (38.7%) reported a sensory outcome; 8 (25.8%) reported a pain outcome; 4 (12.9%) reported a composite foot/ankle score; 3 (9.7%) reported electrodiagnostics; 1 (3.2%) reported a function/disability PRO; 1 (3.2%) reported a psychological outcome; 2 (6.5%) reported an imaging outcome; 3 (9.7%) reported other outcomes. Across the studies, 29 distinct outcome measures were reported.
The outcomes reported in studies on CPN are varied and inconsistent. It is likely that a combination of motor, sensory, pain, and functional outcomes will be needed in a COS to best study CPN. These data will serve as a baseline for the ultimate development of the COS-COPE.

The external popliteal sciatic nerve (EPSN) is the nerve of the lower extremity most frequently affected by compressive etiology. Its superficial and sinuous anatomical course is closely related to other rigid anatomical structures and has an important dynamic neural component. Therefore, this circumstance means that this nerve is exposed to multiple causes of compressive etiology. Despite this fact, there are few publications with extensive case studies dealing with treatment. In this review, we propose to carry out a narrative review of the neuropathy of the EPSN, including an anatomical reminder, its clinical presentation and diagnosis, as well as its surgical and biological approach. The most novel aspect we propose is the review of the possible role of biological factors in the reversal of this situation.

The main nerves in the knee region are the tibial nerve, the common peroneal nerve, and the saphenous nerve. These three nerves innervate the lower leg and foot, providing sensory and motor function. The large sciatic nerve splits just above the knee to form the tibial and common peroneal nerves. The tibial nerve travels down in the posterior region, while the common peroneal nerve runs around the lateral side of the knee and runs down the front of the leg to the foot. Although all these nerves can be affected by injuries of the knee, the infrapatellar branch of the saphenous nerve (IPBSN) and the common peroneal nerve (CPN) are most affected. In this narrative review we focus on neuropathies associated with nerves located in the region of the knee joint in the context of their injuries and possible iatrogenic damage during reconstructive surgery.

Dislocation of the native knee represents a challenging injury, further complicated by the high rate of concurrent injury to the common peroneal nerve (CPN). Initial management of this injury requires a thorough neurovascular examination, given the prevalence of popliteal artery injury and limb-threatening ischemia. Further management of a knee dislocation with associated CPN palsy requires coordinated care involving the sports surgeon for ligamentous knee reconstruction and the peripheral nerve surgeon for staged or concurrent peroneal nerve decompression and/or reconstruction. Finally, the foot and ankle surgeon is often required to manage a foot drop with a distal tendon transfer to restore foot dorsiflexion. For instance, the Bridle Procedure-a modification of the anterior transfer of the posterior tibialis muscle, under the extensor retinaculum, with tri-tendon anastomosis to the anterior tibial and peroneus longus tendons at the anterior ankle-can successfully return patients to brace-free ambulation and athletic function following CPN palsy. Cross-discipline coordination and collaboration is essential to ensure appropriate timing of operative interventions and ensure maintenance of passive dorsiflexion prior to tendon transfer.

UNASSIGNED: Common peroneal nerve palsy (CPNP) after total knee arthroplasty (TKA) may impact extremity pain and function. Incidence and rates of recovery of CPNP after TKA vary in the current literature. The purpose of this systematic review was to evaluate the incidence of incomplete and complete CPNP after TKA and rates of incomplete and complete recovery of nerve function in the absence of further surgical treatment.
UNASSIGNED: PubMed, Embase, and Cochrane Central were searched for studies published in the years 1970-2019. Studies evaluating incidence and recovery rates of CPNP in the absence of further surgical treatment were screened according to inclusion and exclusion criteria. Outcomes of interest included incidence of complete and incomplete CPNP and rates of incomplete and complete nerve recovery.
UNASSIGNED: Eleven studies were included for qualitative analysis. In total, there were 47,585 TKAs performed, with 203 postoperative CPNPs, for a cumulative incidence of 0.4%. One hundred twenty-nine CPNPs were classified as complete or incomplete palsies. At a mean follow-up of 3.6 years (range, 0-11 years), 24 (39%) complete CPNPs had complete recovery, 34 (56%) had incomplete recovery, and 3 were lost to follow-up. In contrast, 45 (66%) with incomplete CPNPs had complete recovery, 18 (27%) had incomplete recovery, and 5 patients were lost to follow-up.
UNASSIGNED: Incidence of CPNP after TKA was 0.4%. Recovery of nerve function after CPNP in the setting of TKA varies by the degree of initial nerve palsy. These data may be used to inform decisions on further interventions and for the purposes of perioperative patient counseling after TKA.

A common cause of peroneal neuropathy is compression near the fibular head. Studies demonstrate excellent outcomes after decompression but include few cases (range 15-60 patients). Consequently, attempts to define predictors of good outcomes are limited. Here, the authors combine their institutional outcomes with those in the literature to identify predictors of good outcomes after peroneal nerve decompression.
The authors searched their institutional electronic medical records to identify all peroneal nerve decompressions performed in the period between December 1, 2012, and September 30, 2016, and created an IRB-approved database. They also conducted a MEDLINE and literature search to identify articles discussing surgical decompression. All data were combined by meta-analysis to identify the factors associated with a favorable outcome, which was defined as improvement in preoperative symptoms. Patients were analyzed in the aggregate and by presentation (pain, paresthesias, weakness, foot drop). The factors evaluated included age, sex, body mass index, diabetes, smoking status, previous knee or lumbar spine surgery, preoperative symptom duration, and etiology. A meta-analysis was completed for any factor evaluated in at least three data sets.
Twenty-one institutional cases had sufficient data for review. The follow-up among this group was long: median 29 months, range 12-52 months. On aggregate analysis of the data, only diabetes was significantly associated with unfavorable outcomes after decompression (p = 0.05). A trend toward worse outcomes was seen in smokers presenting with pain (p = 0.06). Outcomes were not affected by presentation.An additional 115 cases in the literature had extractable data for meta-analysis, and other associations were seen. Preoperative symptom duration longer than 12 months was associated with unfavorable outcomes (OR 0.23, 95% CI 0.08-0.65). Patients presenting with paresthesias or hypesthesia demonstrated a trend toward more unfavorable outcomes when operated on more than 6 months after symptom onset (OR 0.37, 95% CI 0.13-1.06). Even after the meta-analysis, outcomes did not vary with an advanced age (OR 0.70, 95% CI 0.24-1.98) or with patient sex (OR 1.13, 95% CI 0.42-3.06).
The authors provide their institutional data in combination with published data regarding outcomes after peroneal nerve decompression. Outcomes are typically favorable and generally unaffected by the type of symptoms preoperatively, especially if the patient is nondiabetic and preoperative symptom duration is less than 12 months. Patients with paresthesias may benefit from surgery within 6 months after onset. Smoking may adversely affect surgical outcomes. Finally, an advanced age does not adversely affect outcomes, and older patients should be considered for surgery.