Is the phoenix sign phenomenon due to vasodilation? A double-blinded, randomized controlled trial comparing motor function recovery after diagnostic common fibular nerve block with lidocaine and papaverine.

BACKGROUND: Focal entrapment of the common fibular (peroneal) nerve (CFN) is the most common nerve entrapment in the lower extremity. Accurate diagnosis can be difficult due to co-existent pathology such as low back pathology. A 1% lidocaine block of CFN is often used to confirm the local entrapment pathology and demonstrate possibility of pain relief. A surprising, unexpected and temporary strengthening of CFN supplied ankle and foot muscles is occasionally produced, termed the Phoenix sign. Aetiology of this phenomenon has been puzzling, but restoration of neural circulation and nutrition via improved local blood flow has been postulated to be responsible. METHODS: This is a double-blinded, randomized, prospective controlled trial of 20 patients, comparing 2 vasodilating agents and their ability to produce the Phoenix effect. Ultrasound guided infiltration of 0.3 mL 1% lidocaine or papaverine HCl 10 mg/mL was executed adjacent to CFN. Motor strength pre- infiltration and 4 min post-infiltration were measured for anterior compartment muscles utilizing MRC manual motor testing reported on a 0-5 scale. The extensor hallucis longus (EHL) muscle proved to be the most significant. RESULTS: Average motor strength of the EHL improved from 2.2 (+/-0.40) to 4.9 (+/-0.32).) in the lidocaine group. In the papaverine group, pre-infiltration EHL motor strength averaging 2.1 (+/-0.93) improved to 4.4 (+/- 1.01) post-infiltration. Papaverine and lidocaine produced similar statistically significant increases in muscle strength (p = < 0.05). CONCLUSION: There was no difference between small local infiltrations of lidocaine or papaverine in production of increased anterior compartment EHL motor strength. It is most likely that the Phoenix Effect is explained by temporary local improvements in the microcirculation of the CFN vasa nervorum. TRIAL REGISTRATION: NCT06637046 10/10/2024 Retrospectively registered.

Effects of low-frequency pulsed electrical stimulation at the common peroneal nerve on chronic refractory wounds of the lower limb: A randomized controlled trial.

Background and aims: Electrical stimulation (ES) has been shown to substantially enhance the quality of life by alleviating pain in patients with chronic wounds. This study aimed to observe the effects of low-frequency pulsed wearable ES at the common peroneal nerve on chronic refractory wounds of the lower limb. Methods: Forty-eight participants were randomly divided into control group (n = 24) and treatment group (n = 24) in this study. The control group received standard wound care (SWC) exclusively, whereas the treatment group was administered both SWC and the wearable low-frequency ES targeting the common peroneal nerve. Measurements of wound area, pain intensity, wound status, and quality of life scores were systematically recorded both before and after 4 weeks treatment. Results: After 4 weeks of intervention, the percentage area reduction was significantly higher in the treatment group compared to the control group (Z = -3.9, p < 0.001), and the healing rate of the treatment group was significantly higher than that of the control group (33% vs. 4%). Moreover, the visual Analog Scale for Pain score (ß = -0.65, p = 0.019), the Bates-Jensen Wound Assessment Tool score (p < 0.05), and the questionnaire on quality of life with chronic wounds (Wound-Qol) score (ß = -4.23, p = 0.003) were significantly decreased in the patients in the treatment group compared to the control group. Conclusion: The wearable low-frequency pulsed ES at the common peroneal nerve for the treatment of chronic refractory wounds showed significant improvement and were far superior compared to SWC. Future research should broaden its scope to include a diverse range of wound types and benefit from collaboration across multiple research centers.

The Rare Large Common Peroneal Nerve's Schwannoma-A Case Report and Literature Review.

Schwannoma in the popliteal fossa is still rare, often diagnosed late because it grows slowly and has no symptoms. It is often misdiagnosed with connective tissue tumors or with neurological disorders originating in the spine or disorders of the peroneal nerve. Schwannoma within the common peroneal nerve is still rare in the popliteal fossa, with most tumor sizes around 2 cm in diameter due to their smaller size of nerve but can cause neurologic disturbance, especially when it is large. And over a long time, it can cause serious complaints like neurological deficits and make surgery difficult by leaving greater sequelae. There is no data yet showing the incidence of schwannoma in the common peroneal nerve. In this case, a 36-year-old woman, for 5 years, feels soreness in the popliteal fossa and pain in the right instep, suspected that a nerve was pinched, due to an abnormality in the spine. As time went on, there was a lump in the fold of the right knee, suspected to be a Baker's cyst. As time went by, the complaint was burning pain in the right instep to the lateral ankle and distal right lower leg, disturbing sleep. Tinel's sign was positive. The right instep has hypoesthesia and a slight drop in the foot. On radiological examination of the right knee, a circumferential mass appeared, measuring 5 cm × 4 cm. The diagnosis is suspicious for a common peroneal nerve tumor. The encapsulated operation to remove the tumor was carried out with a size measuring 5 cm × 4.5 cm × 4 cm. The histopathological examination showed schwannoma. After surgery, the pain disappeared, hypoesthesia and a slight drop in the foot underwent physiotherapy, and stimulation with the result gradually improved. A thorough early examination includes correct and systematic anamnesis, physical examination, and neurological evaluation such as paraesthesia, hypoesthesia, and Tinel's sign; also, additional examinations, such as radiographic, ultrasound, and MRI, are needed for early detection of schwannoma so that delays in diagnosis and surgery can be avoided to prevent neurological deficits.

Proximal Fibulectomy for Giant Cell Tumours: What Works!

Background: Giant cell tumor of bone (GCTB) is the most common primary tumor of proximal fibula. Because of its close proximity to vascular structures, common peroneal nerve (CPN) and attachment of lateral collateral ligament (LCL), proximal fibulectomy poses unique challenges. We analyzed oncological and functional outcome of patients who underwent proximal fibulectomy for GCTB of proximal fibula. Material and methods: Between January 2006 and December 2020, 23 patients underwent proximal fibulectomy for GCTB of proximal fibula, four were recurrent tumors. Mean resection length was 9 cm (5 to 15 cm). The LCL and biceps tendon were not reconstructed in 22 cases. The common peroneal nerve was sacrificed in seven patients including three recurrent cases. Functional status was assessed using the Musculoskeletal Tumour Society (MSTS) scoring system. Results: There were two vascular complications and one infection. With 4 patients lost to follow up, mean follow up was 90 months (12 to 197). No patient had local or distant recurrence. Mean MSTS score was 26 (21 to 30). Eleven of 23 patients (48%) had loss of common peroneal nerve function with poorer functional outcome. No patient had symptoms suggestive of knee instability. Conclusion: Proximal fibulectomy is oncologically safe. Reconstruction of the LCL attachment is not mandatory and patients do not have symptomatic knee instability. Functional outcomes are compromised after sacrifice of common peroneal nerve and may be potentially improved with tendon transfers at index surgery.

Ultrasound evaluation and grading of neuromuscular disease in lower extremities among diabetic patients.

OBJECTIVE: To explore the clinical utility of ultrasound in evaluating and grading neuromuscular diseases in the lower extremities of patients with diabetes mellitus. METHODS: A total of 126 inpatients from the Department of Diabetes at Zhangzhou Affiliated Hospital of Fujian Medical University, China, were recruited from June 2020 to December 2022. The cohort included 69 patients with type 2 diabetes mellitus (T2DM) and diabetic peripheral neuropathy (DPN group) and 57 patients with T2DM but without DPN (non-DPN group). Additionally, 80 healthy controls were included. High-frequency ultrasound was used to scan the common peroneal, sural, and tibial nerves, measuring their transverse (D1) and anteroposterior (D2) diameters, and calculating the cross-sectional area (CSA). Changes in the internal echo of the extensor digitorum brevis (EDB) muscle, including maximum thickness and CSA, were also recorded. The DPN group was further subdivided based on disease duration to assess ultrasonic changes over time and the statistical significance of these variations. RESULTS: Ultrasonic changes such as uneven internal echo reduction, ill-defined epineurial boundaries, and obscured cribriform structures were most prevalent in the DPN group. Significant differences in ultrasound parameters (D1, D2, CSA) were observed among the groups (all P<0.05), with the most pronounced changes in the DPN group. In patients with a disease duration of over 15 years, a significant increase in CSA of lower extremity nerves and a decrease in CSA of the EDB were noted compared to those in the 5-10 years subgroup (19.89±0.98 vs 19.00±0.94; 5.25±0.74 vs 5.93±0.94; all P<0.05). CONCLUSIONS: High-frequency ultrasound provides a valuable imaging basis for diagnosing and monitoring DPN, demonstrating significant changes in nerve and muscle parameters among diabetic patients.

Core outcomes in nerve surgery: development of a core outcome set for common peroneal (fibular) neuropathy.

OBJECTIVE: Common peroneal (fibular) neuropathy is the most common mononeuropathy of the lower extremity. Despite this, there are surprisingly few studies on the topic, and a knowledge gap remains in the literature. As one attempts to address this knowledge gap, a core outcome set (COS) is needed to guide the planning phases of future studies to allow synthesis and comparability of these studies. The objective of this study was to develop the COS-common peroneal neuropathy (CoPe) using a modified Delphi approach. METHODS: A 5-stage approach was used to develop the COS-CoPe: 1) stage 1, consortium development; 2) stage 2, a literature review to identify potential outcome measures; 3) stage 3, a Delphi survey to develop consensus on outcomes for inclusion; 4) stage 4, a Delphi survey to develop definitions; and 5) stage 5, a consensus meeting to finalize COS and definitions. The study followed the COS-STAndards for Development (COS-STAD) recommendations. RESULTS: The Core Outcomes in Nerve Surgery (COINS) Consortium comprised 23 participants, all neurological surgeons, representing 13 countries. The final COS-CoPe consisted of 31 data points/outcomes covering domains of demographics, diagnostics, patient-reported outcomes, motor/sensory outcomes, and complications. Appropriate instruments, methods of testing, and definitions were set. The consensus minimum duration of follow-up was 12 months. The consensus optimal time points for assessment were preoperatively and 3, 6, 12, and 24 months postoperatively. CONCLUSIONS: The COINS Consortium developed a consensus COS and provided definitions, methods of implementation, and time points for assessment. The COS-CoPe should serve as a minimum set of data that should be collected in all future neurosurgical studies on common peroneal neuropathy. Incorporation of this COS should help improve consistency in reporting, data synthesis, and comparability, and should minimize outcome reporting bias.

High-Grade Malignant Peripheral Nerve Sheath Tumor Arising From Common Peroneal Nerve Neurofibroma.

This article presents a case report of a 45-year-old male with neurofibromatosis type I (NF1) who developed a high-grade malignant peripheral nerve sheath tumor (MPNST) originating from a neurofibroma within the common peroneal nerve over popliteal fossa. MPNSTs are aggressive tumors associated with NF1, causing significant mortality. The patient underwent tumor resection surgery and received postoperative radiation therapy. Follow-up examinations showed no impairment of motor function and no tumor recurrence after regular MRI evaluation for four years. This article explores the challenges of distinguishing benign neurofibromas from malignant MPNST via MRI image and biopsy, and achieving a balance between tumor excision and preserving nerve functionality during surgical treatment. However, caution is warranted due to the risk of recurrence.

Palsy of Both the Tibial Nerve and Common Peroneal Nerve Caused by a Ganglion Cyst in the Popliteal Area.

A ganglion cyst is a benign mass consisting of high-viscosity mucinous fluid. It can originate from the sheath of a tendon, peripheral nerve, or joint capsule. Compressive neuropathy caused by a ganglion cyst is rarely reported, with the majority of documented cases involving peroneal nerve palsy. To date, cases demonstrating both peroneal and tibial nerve palsies resulting from a ganglion cyst forming on a branch of the sciatic nerve have not been reported. In this paper, we present the case of a 74-year-old man visiting an outpatient clinic complaining of left-sided foot drop and sensory loss in the lower extremity, a lack of strength in his left leg, and a decrease in sensation in the leg for the past month without any history of trauma. Ankle dorsiflexion and great toe extension strength on the left side were Grade I. Ankle plantar flexion and great toe flexion were Grade II. We suspected peroneal and tibial nerve palsy and performed a screening ultrasound, which is inexpensive and rapid. In the operative field, several cysts were discovered, originating at the site where the sciatic nerve splits into peroneal and tibial nerves. After successful surgical decompression and a series of rehabilitation procedures, the patient's neurological symptoms improved. There was no recurrence.

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.

Background: Detailed knowledge of the anatomic course of the common peroneal nerve (CPN) is crucial for the surgical treatment of the posterolateral corner (PLC) of the knee. Purpose: To investigate the relationship of the CPN to the PLC of the knee at different flexion angles. Study Design: Descriptive laboratory study. Methods: Ten healthy volunteers were recruited to undergo magnetic resonance imaging (MRI) of the knee joint at knee flexion angles of 0°, 30°, 60°, 90°, and 120°. MRI scans at 3 levels (joint line, tibial cut, and fibular tip) were evaluated to determine (1) the distance from the CPN to the PLC and (2) the distances between the CPN and the anterior-posterior and medial-lateral tibial axes. A 3-dimensional model of the knee joint created from MRI scans of a single participant was used to simulate the creation of a fibular tunnel for PLC reconstruction and investigate the relationship between the CPN, fibular tunnel, and guide pin. Results: The CPN moved posteromedially with increased knee flexion angles. As the flexion angle increased, the distances from the CPN to the anterior-posterior axis and the PLC increased significantly, while the distance to the medial-lateral axis decreased significantly at all 3 measurement levels. The distances between the CPN and anterior-posterior and medial-lateral axes were significantly different among the different knee flexion angles at the different measurement levels. There were no significant differences in the mean distance from the CPN to the posterolateral border of the tibial plateau between 0° and 30° of flexion at the fibular tip level (P = .953). There were statistically significant differences in the distance from the CPN to the PLC of the tibial plateau at the different measurement levels. The 3-dimensional model demonstrated that the position of the CPN relative to the guide pin and the bone tunnel undergoes changes during knee flexion. Conclusion: Changes in the knee flexion angle produced corresponding changes in the course of the CPN on the posterolateral aspect of the knee joint. The CPN moved posteromedially with increased knee flexion angles. Clinical Relevance: Increasing the knee flexion angle during PLC reconstruction can effectively avoid direct injury of the CPN.

Case Report: Acute common peroneal nerve injury after posterior lumbar decompression surgery.

Spine surgery is a prevalently performed procedure. Some authors have proposed an age-related surge in surgical and general complications. During spine surgery, patients are placed in positions that are not physiologic, would not be tolerated for prolonged periods by the patient in the awake state, and may lead to complications. Understanding these uncommon complications and their etiology is pivotal to prevention and necessary. The patient is a 76-year-old woman referred to the outpatient department of neurosurgery in February 2022 by her physiatrist with a chief complaint of chronic low back pain and numbness over the left leg. Lumbar spine magnetic resonance imaging revealed degenerative disc disease and posterior disc bulging at the levels of L2/3∼L5/S1 with compression of the thecal sac. After receiving anti-inflammatory medication, nerve block and caudal block, her symptoms persisted. She was referred to a neurosurgeon for surgical intervention. We diagnosed spinal stenosis with left L3 and L4 radiculopathy, and elective decompression surgery was scheduled a few days later. We performed discectomies at L2/3 and L3/4 and left unilateral laminectomy at L2 and L3 for bilateral decompression. Following an uneventful surgery, the patient was extubated, and her left leg pain improved, but pain over the right outer calf with drop foot developed. A second lumbar MRI the next day revealed no evidence of recurrent disc herniation or epidural hematoma. Then, she received nerve conduction velocity and needle electromyogram on postoperative day 2, and the studies indicated right common peroneal nerve entrapment neuropathy. After medication with steroids and foot splint use, right leg pain improved. However, weak dorsiflexion of the right ankle persisted. We referred this patient to a physiatrist and OPD for follow-up after discharge. Perioperative peripheral nerve injury (PPNI) is most commonly caused by peripheral nerve ischemia due to abnormal nerve lengthening or pressure and can be exacerbated by systemic hypotension. Any diseases affecting microvasculature and anatomical differences may contribute to nerve injury or render patients more susceptible to nerve injury. Prevention, early detection and intervention are paramount to reducing PPNI and associated adverse outcomes. The use of intraoperative neuromonitoring theoretically allows the surgical team to detect and intervene in impending PPNI during surgery.

Left common peroneal nerve palsy caused by cross-legged sitting during epidural labor analgesia: a case report.

BACKGROUND: Nerve injury in epidural labor analgesia can occur with various potential causes. We report a rare case of left common peroneal nerve palsy after delivery caused by a prolonged period of sitting cross-legged during epidural labor. CASE REPORT: Epidural labor analgesia in a 28-year-old primipara started at 39 weeks of gestation. She sat cross-legged to prompt delivery for approximately 4 h with a break of a few minutes every hour. She had numbness in her left lower limb and difficulty in dorsiflexion of the ankle joint that did not improve until 3 h after delivery. We made a diagnosis of left common peroneal nerve palsy. Most of the symptoms had improved at 2 months postpartum. CONCLUSION: Epidural labor analgesia prevented recognition of prolonged peroneal head compression caused by sitting cross-legged. When this position is used to facilitate delivery, it should be released frequently owing to the possibility of a neurologic deficit.

Peroneal Nerve Palsy After Total Knee Arthroplasty.

Background: Common peroneal nerve palsy (CPNP) is a rare complication of total knee arthroplasty (TKA). It may lead to impaired function and pain. The purpose of this study was to determine the frequency and outcome of CPNP in a single orthopedic unit and to identify potential risk factors. Methods: This is a single-center study using the hospital's prospectively collected quality registry. All TKAs from 2002 to 2022 were included and followed up from 3 to 24 months with a follow-up rate of 98.4%. The local joint register was reviewed to identify patients with CPNP and used to extract data regarding the operation and the patients with and without CPNP. The groups were compared to identify possible risk factors for nerve injury. The medical records of the patients with CPNP were reviewed to determine the CPNPs' severity and outcome, and their preoperative radiographs were analyzed and compared to a control group with no nerve injury. Results: A total of 7704 TKAs were included, and 25 CPNPs were identified (0.32%). Complete palsies occurred in 18 cases, and partial palsies in 7. Postoperative epidural anesthesia, preoperative excessive valgus, and female sex were significant risk factors. Body mass index and age were not associated with CPNP. Two-thirds of the complete palsies had complete recovery, and four-fifths of the partial palsies recovered. Conclusions: The incidence of CPNP was 0.32%, and risk factors were epidural anesthesia, excessive valgus, and female sex. Most patients with CPNP recovered completely. Partial palsies had better outcomes than complete palsies in our cohort.

Functional outcomes of different surgical treatments for common peroneal nerve injuries: a retrospective comparative study.

BACKGROUND: This study aims to assess the recovery patterns and factors influencing outcomes in patients with common peroneal nerve (CPN) injury. METHODS: This retrospective study included 45 patients with CPN injuries treated between 2009 and 2019 in Jing'an District Central Hospital. The surgical interventions were categorized into three groups: neurolysis (group A; n = 34 patients), nerve repair (group B; n = 5 patients) and tendon transfer (group C; n = 6 patients). Preoperative and postoperative sensorimotor functions were evaluated using the British Medical Research Council grading system. The outcome of measures included the numeric rating scale, walking ability, numbness and satisfaction. Receiver operating characteristic (ROC) curve analysis was utilized to determine the optimal time interval between injury and surgery for predicting postoperative foot dorsiflexion function, toe dorsiflexion function, and sensory function. RESULTS: Surgical interventions led to improvements in foot dorsiflexion strength in all patient groups, enabling most to regain independent walking ability. Group A (underwent neurolysis) had significant sensory function restoration (P < 0.001), and three patients in Group B (underwent nerve repair) had sensory improvements. ROC analysis revealed that the optimal time interval for achieving M3 foot dorsiflexion recovery was 9.5 months, with an area under the curve (AUC) of 0.871 (95% CI = 0.661-1.000, P = 0.040). For M4 foot dorsiflexion recovery, the optimal cut-off was 5.5 months, with an AUC of 0.785 (95% CI = 0.575-0.995, P = 0.020). When using M3 toe dorsiflexion recovery or S4 sensory function recovery as the gold standard, the optimal cut-off remained at 5.5 months, with AUCs of 0.768 (95% CI = 0.582-0.953, P = 0.025) and 0.853 (95% CI = 0.693-1.000, P = 0.001), respectively. CONCLUSIONS: Our study highlights the importance of early surgical intervention in CPN injury recovery, with optimal outcomes achieved when surgery is performed within 5.5 to 9.5 months post-injury. These findings provide guidance for clinicians in tailoring treatment plans to the specific characteristics and requirements of CPN injury patients.

Sleep disturbance correlated with severity of neuropathic pain in sciatic nerve crush injury model.

The association between sleep and pain has been investigated widely. However, inconsistent results from animal studies compared with human data show the need for a validated animal model in the sleep-pain association field. Our study aims to validate common neuropathic pain models as a tool for evaluating the sleep-pain association. Electrodes electroencephalogram (EEG) and electromyogram (EMG) were surgically implanted to measure sleep. The von Frey test was used to measure pain sensitivity. Following the baseline data acquisition, two pain-modelling procedures were performed: sciatic nerve crush injury (SCI) and common peroneal nerve ligation (CPL). Post-injury measurements were performed on days 1, 5, 10, and 15 post-surgery. The results presented decreased paw withdrawal thresholds and reduced NREM sleep duration in both models on the first post-surgery day. In the SCI model, NREM sleep duration was negatively correlated with paw withdrawal thresholds (p = 0.0466), but not in the CPL model. Wake alpha and theta EEG powers were also correlated with the pain threshold. The results confirm that the SCI model shows disturbed sleep patterns associated with increased pain sensitivity, suggesting it is a reliable tool for investigating sleep disturbances associated with neuropathic pain.

Prophylactic Common Peroneal Nerve Decompression Avoids Nerve Palsy in Total Knee Arthroplasty for Severe Fixed Valgus Deformity: A Report of Four Cases and Review of Literature.

Common peroneal nerve (CPN) injury is a serious complication following total knee arthroplasty (TKA). We aim to report four patients (five knees) who underwent prophylactic peroneal nerve decompression for severe rigid valgus deformity with or without associated fixed flexion deformity that was not correctable under anaesthesia. The preoperative deformity of 31.1° valgus by femorotibial angle (range 22.6-37.9°) improved to 7.1° valgus (range 4.3-9.1°) postoperatively (p < 0.05). For two knees, varus-valgus constrained was used due to medial laxity and the other three had posterior-stabilised prosthesis. All four patients had normal motor or sensory nerve function of the CPN nerve postoperatively. There was a significant improvement in the functional outcome by knee society score and knee society functional score from 17.8 ± 6.8, 25 ± 16.2 to 84 ± 8.7, 83 ± 10.3, respectively (p < 0.05). No complications were noted in the mean follow-up of 1.2 years. Prophylactic peroneal nerve decompression allows safe, adequate and optimal lateral soft-tissue release. It is effective in preventing common peroneal nerve palsy in high-risk patients like severe valgus and flexion deformity during total knee arthroplasty.

The distance between the fibular collateral ligament tunnel and the common peroneal nerve allows a posterolateral corner reconstruction without neurolysis.

PURPOSE: The most popular knee posterolateral corner (PLC) reconstruction techniques describe that a common peroneal nerve (CPN) neurolysis must be done to safely address the posterolateral aspect of the knee. The purpose of this study was to measure the distance between the CPN and the fibular insertion of the FCL in different degrees of knee flexion in cadaveric specimens, to identify if tunnel drilling could be done anatomically and safely without a CPN neurolysis. METHODS: Ex vivo experimental analytical study. Ten fresh frozen human knees were dissected leaving FCL and CPN in situ. Shortest distance from the centre of the FCL distal tunnel and CPN was measured (antero-posterior and proximal-distal wire-nerve distances) at 90°, 60°, 30°, and 0° of knee flexion. Measurements between different flexion angles were compared and correlation between knee flexion angle and distance was identified. RESULTS: The mean distance between the FCL tunnel and the CPN at 90° were 21.15 ± 6.74 mm posteriorly (95% CI: 16.33-25.97) and 13.01 ± 3.55 mm distally (95% CI: 10.47-15.55). The minimum values were 9.8 mm posteriorly and 8.9 mm, respectively. These distances were smaller at 0° (p ≤ 0.017). At 90° of knee flexion, the mean distance from the fibular tip to the CPN distally was 23.46 ± 4.13 mm (20.51-26.41). CONCLUSION: Anatomic localization and orientation of fibular tunnels can be done safely while avoiding nerve neurolysis. Further studies should aim to in vivo measurements and results.

Deep Learning-Based Knee MRI Classification for Common Peroneal Nerve Palsy with Foot Drop.

Foot drop can have a variety of causes, including the common peroneal nerve (CPN) injuries, and is often difficult to diagnose. We aimed to develop a deep learning-based algorithm that can classify foot drop with CPN injury in patients with knee MRI axial images only. In this retrospective study, we included 945 MR image data from foot drop patients confirmed with CPN injury in electrophysiologic tests (n = 42), and 1341 MR image data with non-traumatic knee pain (n = 107). Data were split into training, validation, and test datasets using a 8:1:1 ratio. We used a convolution neural network-based algorithm (EfficientNet-B5, ResNet152, VGG19) for the classification between the CPN injury group and the others. Performance of each classification algorithm used the area under the receiver operating characteristic curve (AUC). In classifying CPN MR images and non-CPN MR images, EfficientNet-B5 had the highest performance (AUC = 0.946), followed by the ResNet152 and the VGG19 algorithms. On comparison of other performance metrics including precision, recall, accuracy, and F1 score, EfficientNet-B5 had the best performance of the three algorithms. In a saliency map, the EfficientNet-B5 algorithm focused on the nerve area to detect CPN injury. In conclusion, deep learning-based analysis of knee MR images can successfully differentiate CPN injury from other etiologies in patients with foot drop.

Delayed Recovery of Idiopathic Common Peroneal Nerve Palsy After Total Knee Arthroplasty: A Rare Case Report.

Introduction: Common peroneal nerve palsy (CPNP) is a rare complication post total knee arthroplasty (TKA). Even though it is diagnosed acutely, the recovery potential is just over 50%. The average period for complete recovery in such cases is 5 months; however, the management remains controversial. Through this report, we present one such case of left sided complete CPNP after bilateral TKA who was conserved with various modalities. Even though the recovery was delayed, the patient made full recovery. Case Report: A 70-year-old female patient was diagnosed to have bilateral tricompartmental knee osteoarthritis with varus deformity, both clinically and radiologically (Kellgren-Lawrence grade 4). She underwent bilateral TKA in a single sitting as per the standard protocols practiced by the primary author. On post-operative day 1, she had left-sided foot drop with a complete sensory deficit. The patient underwent routine rehabilitation with an ankle foot orthosis splint in the immediate post-operative period, with simultaneous faradic current stimulation for the left lower limb. Periodic electromyography and nerve conduction study was done at the end of 4-week and 3-month post-TKA. At 6.5-month post-surgery, she made a full clinical recovery. Conclusion: The surgical maneuvers and full neurovascular examination before and after every TKA surgery should be carefully performed. Despite this, if a patient presents with CPNP, the surgeon need not take an aggressive approach, unlike fracture fixation cases. These patients can be managed conservatively using appropriate orthosis, physical therapy, and faradic current stimulation. Through this case, we attempt to report that CPNP patient can recover even after 6 months of surgery when there is no tangible cause for the palsy.

Common peroneal nerve injury after tibial plateau fractures: A case series.

Introduction: Common peroneal nerve (CPN) injury is a rare but significant complication of knee trauma. Given its low incidence, there is limited published evidence, but reports have shown dislocations and fractures associated with varus deformity are more likely to injure the nerve, causing foot drop. This study aims to document the incidence and outcome of CPN palsy in tibial plateau fractures (TPF). Methods: We reviewed 746 cases of tibial plateau fractures treated between 2011 and 2020. We analysed patients' demographics, injury mechanisms, clinical course, and complications, and identified those with CPN palsies. Fractures were classified using the Schatzker, Luo and AO/OTA systems. The details of the CPN injury, including nerve conduction studies, duration of symptoms and outcome were recorded. Results: We identified 11 patients who had concurrent TPFs and CPN palsies, an overall incidence of 1.47 %. Most fractures involved the medial column (n = 9), with the C3 fragmentary TPF pattern being the most common (n = 4). The incidence of CPN injury was higher in medial fractures (5 %) and bicondylar fractures (3 %). We also found that most patients (n = 9) recovered full neurological function within 2 years. Discussion: This is the first study looking at a patient cohort sustaining concurrent TPFs and CPN injuries. It is a rare complication but should be looked for in high-risk medial and bicondylar fractures. We found that prognosis is better in TPF-associated CPN palsy than in other knee trauma, and that the majority of patients can expect a full recovery of nerve function.

Analysis of outcome reporting in common peroneal neuropathy studies: a systematic review of the literature.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.