Erosion of Stumble Correction Evoked with Superficial Peroneal Nerve Stimulation in Older Adults during Walking.

In healthy young adults, electrical stimulation of the superficial peroneal cutaneous nerve (SPn) innervating the dorsum of the foot has been shown to elicit functionally relevant reflexes during walking that are similar to those evoked by mechanical perturbation to the dorsum of the foot during walking and are referred to as stumble corrective (obstacle avoidance) responses. Though age-related differences in reflexes induced by mechanical perturbation have been studied, toe clearance has not been measured. Further, age-related differences in reflexes evoked by electrical stimulation of SPn have yet to be determined. Thus, the purpose of this study was to characterize age-related differences between healthy young adults and older adults with no history of falls in stumble correction responses evoked by electrical stimulation of the SPn at the ankle during walking. Toe clearance relative to the walking surface along with joint displacement and angular velocity at the ankle and knee and EMG of the tibialis anterior, medial gastrocnemius, biceps femoris and vastus lateralis were measured. The combined background and reflex toe clearance was reduced in the older adults compared with the young in mid-early swing (p = 0.011). These age-related differences likely increase fall risk in the older adult cohort. Further, age-related changes were seen in joint kinematics and EMG in older adults compared with the young such as decreased amplitude of the plantarflexion reflex in early swing in older adults (p < 0.05). These altered reflexes reflect the degradation of the stumble corrective response in older adults.

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.

[Superficial peroneal nerve entrapment: ultrasound-guided hydrodissection. A case report]. / Atrapamiento de nervio peroneo superficial: hidrodisección ecoguiada. A propósito de un caso.

Peripheral nerve entrapment is an underdiagnosed pathology when it is not the most common syndromes such as carpal tunnel syndrome or cubital tunnel syndrome. The symptomatic lesion of the superficial peroneal nerve (SPN) has a low incidence, being its diagnosis sometimes complex. It is based on a exhaustive physical examination and imaging tests such as ultrasound (US) or magnetic resonance imaging (RMI). Conservative treatment may sometimes not be sufficient, requiring surgical techniques in refractory cases. We present a patient diagnosed with superficial peroneal nerve entrapment by ultrasound and diagnostic nerve block that was subsequently resolved by hydrodissection technique at the level of the deep crural fascia tunnel. The results were satisfactory with a complete resolution of the clinical process since the application of this technique.

A Curious Case of Common Peroneal Nerve Schwannoma.

Schwannoma or neurilemmoma is a slow-growing tumor that develops from nerve sheaths. It is mostly benign and only rarely transforms into malignancy. The incidence of schwannoma is very low in the lower limbs. Schwannomas developing from the common peroneal nerve is unlikely. A middle-aged male presented with complaints of left knee pain, which was radiating to the left foot, and a painful swelling at the back of the knee. An intralesional excision was done, and the patient made a full recovery with no postoperative complications. The excised specimen was found to be a schwannoma of the common peroneal nerve of the left leg. At the one-month, three-month, and one-year postoperative follow-ups, the patient had no complaints of pain on passive and active dorsiflexion of the foot. There was complete recovery from paresthesia and intact sensation was present. This report shows that asymptomatic schwannomas can sometimes present with symptoms of pain. In such cases, careful and complete excision of the schwannoma can lead to full recovery.

Outcomes of Nerve Transfers in Peroneal Nerve Palsy.

Background: The objective of this work is to: (i) evaluate the postoperative outcomes after lower extremity nerve transfer (LENT) in patients with peroneal nerve palsy, and (ii) evaluate the patient and surgical factors that best predict successful restoration of ankle dorsiflexion following nerve transfer. Methods: A retrospective cohort of prospectively collected data included all patients who underwent LENT (2010-2018). Two independent reviewers performed data collection. Primary outcome measures were: (i) clinically with British Medical Research Council (MRC) strength assessments, and (ii) electrodiagnostically with nascent motor unit potentials. Statistical analysis was performed using descriptive and nonparametric statistics. Results: Nine patients (56% male, mean age 38.3, range 18-57 years) underwent LENT surgery a mean of 4.3 months following injury (range 2.2-6.4 months). Mean follow-up was 15.6 months (range 9.1-28.2 months). Postoperatively, ankle dorsiflexion (P = .015) and ankle eversion (P = .041) increased significantly. After surgery, 44% achieved MRC 4, 33% obtained MRC 1 motor recovery, and 22% sustained MRC 0. A shorter time to surgery was associated with significantly better outcomes (P = .049). Conclusions: It appears that there is a bimodal distribution between responders and nonresponders to LENT for foot drop. Further research is required to elucidate patient and surgical factors that prognosticate success.

Contexte: Les objectifs de cette étude étaient les suivants : (i) évaluer les résultats postopératoires après un transfert de nerf dans le membre inférieur (LENT; lower extremity nerve transfer) chez des patients ayant une paralysie du nerf péronier et (ii) évaluer les facteurs propres au patient et à la chirurgie qui permettent de prédire le mieux possible le succès d'une restauration de la dorsiflexion de la cheville après le transfert nerveux. Méthodes: Une cohorte rétrospective de données collectées de façon prospective a inclus tous les patients ayant bénéficié d'un LENT de 2010 à 2018. Deux réviseurs indépendants ont réalisé la collecte des données. Les critères de jugement principaux étaient les suivants : (i) cliniques avec des évaluations de la force selon l'échelle MRC et (ii) électrodiagnostiques avec potentiels d'unités motrices naissantes. Une analyse statistique a été réalisée au moyen de statistiques descriptives et non paramétriques. Résultats: Neuf patients (hommes : 56%, âge moyen : 38,3 ans, extrêmes : 18 à 57 ans) ont subi une LENT, en moyenne 4,3 mois après une blessure (extrêmes : 2,2 à 6,4 mois). Le suivi moyen a été de 15,6 mois (extrêmes : 9,1 à 28,2 mois). En postopératoire, la dorsiflexion de la cheville (P = 015) et l'éversion de la cheville (P = 041) ont augmenté de façon significative. Après l'intervention chirurgicale, 44% des patients ont atteint un score de 4 sur l'échelle MRC, 33% ont obtenu une récupération motrice cotée à 1 et 22% ont conservé une cote MRC de 0. Un délai plus court avant la chirurgie a été associé à des résultats significativement meilleurs (P = .049). Conclusions: Il semble y avoir une répartition bimodale entre les répondeurs et les nonrépondeurs à la chirurgie de LENT pour la chute du pied. Des recherches supplémentaires sont nécessaires pour renseigner les facteurs pronostiques de succès liés au patient et à l'intervention chirurgicale.

Common Peroneal Nerve and Tarsal Tunnel Release Surgery in an Adolescent Male with Hunter Syndrome: Illustrative Case.

BACKGROUND: Children with Hunter syndrome have a high prevalence of nerve compression syndromes given the buildup of glycosaminoglycans in the tendon sheaths and soft tissue structures. These are often comorbid with orthopedic conditions given joint and tendon contractures due to the same pathology. While carpal tunnel syndrome and surgical treatment has been well-reported in this population, the literature on lower extremity nerve compression syndromes and their treatment in Hunter syndrome is sparse. OBSERVATIONS: We report the case of a 13-year-old male with a history of Hunter syndrome who presented with toe-walking and tenderness over the peroneal and tarsal tunnel areas. He underwent bilateral common peroneal nerve and tarsal tunnel releases, with findings of severe nerve compression and hypertrophied soft tissue structures demonstrating fibromuscular scarring on pathology. Post-operatively, the patient's family reported subjective improvement in lower extremity mobility and plantar flexion. LESSONS: In this case, peroneal and tarsal nerve compression were diagnosed clinically and treated effectively with surgical release and postoperative ankle casting. Given the wide differential of common comorbid orthopedic conditions in Hunter syndrome and the lack of validated electrodiagnostic normative values in this population, the history and physical examination and consideration of nerve compression syndromes are tantamount for successful workup and treatment of gait abnormalities in the child with Hunter syndrome.

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.

One-stage Neurorrhaphy and Posterior Transposition with Gastrocnemius Fascial Flap for Common Peroneal Nerve Injury: Preliminary Results.

OBJECTIVE: Common peroneal nerve (CPN) injury is a frequently encountered lower extremity injury. Furthermore, several previous studies have demonstrated that patients who underwent direct suturing of the CPN following rupture experienced unfavorable postoperative prognoses. Therefore, we aimed to present a novel modified surgical approach for CPN rupture and assess the effectiveness of this technique in restoring lower limb functionality. METHODS: In this retrospective observational study, we included patients with CPN rupture who underwent one-stage neurorrhaphy and posterior transposition combined with nerve wrapping using a gastrocnemius fascial flap for CPN rupture between January 2016 and December 2020. Lower limb function was evaluated using the lower extremity functional scale (LEFS) and British Medical Research Council (BMRC) grading system. We also assessed the influence of age, sex, duration of symptoms, mechanism of injury, and surgical modality on the postoperative recovery of lower extremity function using subgroup and regression analyses. RESULTS: Thirty-seven patients (mean age = 35.76 ± 13.01 years) with at least 2 years of follow-up were included in the final analysis. The LEFS scores significantly improved after surgery at the last follow-up (p < 0.01). Moreover, 67.57% of the patients achieved good or excellent postoperative outcomes (BMRC: M3 or above). Results of the subgroup analysis and regression models suggested that patients who underwent direct suturing showed better recovery of lower extremity function than those who underwent nerve grafting. CONCLUSION: One-stage neurorrhaphy and posterior transposition combined with nerve wrapping using a gastrocnemius fascial flap exhibited encouraging outcomes in restoring lower-limb function among patients with CPN rupture. This novel surgical technique is expected to be an effective method for treating CPN ruptures in the future.

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.

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.

Exploration of the right peroneal nerve after a gunshot wound.

Background: Gunshot wounds (GSWs) often result in neuropraxia or a mixed injury pattern rather than direct nerve transection. There is still debate between early and delayed intervention for the optimal treatment of intact nerves following GSWs. Early intervention may prevent the formation of dense scar tissue, and delayed intervention allows for the zone of injury to be fully demarcated for optimal treatment planning. Here, we present the case of a 29-year-old male who underwent exploration of the right common peroneal nerve after a GSW. Case Description: A 29-year-old male presented for evaluation of a GSW to the right lower extremity at the level of the fibular head he sustained 2 months prior. Following his injury, he was immediately evaluated in the emergency department and offered supportive care. He reported paresthesias in the right lower extremity and a right-sided foot drop. Computed tomography demonstrated a bullet fragment in the distal right lower extremity, and ultrasound revealed a partial thickness injury in the right peroneal nerve. Exploration of the right common peroneal nerve and bullet fragment was recommended. The bullet fragment was removed from the distal right lower extremity in one piece. Following this, the right common peroneal nerve was decompressed proximally to distally, with scar tissue encountered distally. Postoperatively, the patient did well, ambulating shortly after surgery, and at 3 weeks postoperative, he was ambulating without difficulty. Conclusion: Clinical judgment and risk-benefit analysis of each patient must be made individually to determine the most optimal treatment method following GSWs.

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.

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.

Common Peroneal Nerve Injury Caused by a Wild Boar Attack.

Wild boar-inflicted nerve injuries have been very rarely reported in the literature. A 62-year-old man was attacked by a wild boar in eastern Turkey and brought to the emergency department. He had 5 lacerations on the lower extremities and 2 on the posterior thoracic region. In addition to soft tissue lacerations, he sustained a complete laceration of the left common peroneal nerve with a foot drop. The common peroneal nerve was repaired primarily the day after the attack. The patient was discharged after a short hospital stay without any immediate complications; however, at the 10-mo follow-up, he still had a left foot drop.

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.

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.

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.

[Treatment of acute knee dislocations]. / Behandlung der akuten Knieluxation.

A knee dislocation is a serious injury involving at least two of the four major ligamentous stabilizers of the knee. This injury results in multidirectional knee instability. In dislocation of the knee the popliteal artery and the peroneal nerve can also be damaged. Dislocations with vascular involvement are potentially threatening injuries of the lower extremities. The diagnosis of knee dislocation can be difficult due to a high rate of spontaneous reduction at the initial examination. Knee dislocations are rare and mainly occur in young men. They are mostly caused by high-energy trauma; however, they can also be caused by low-energy injuries. Obesity increases the risk of knee dislocations. The classification of a knee dislocation is based on the anatomical structures involved and the direction of dislocation. The acute treatment includes reduction and stabilization measures. Associated injuries, such as vascular, nerve, extensor mechanism and cartilage injuries as well as fractures and meniscal injuries can influence the treatment approach and the outcome. The definitive surgical treatment depends on the severity of the injury and can include ligament reconstruction or repair with bracing. The aftercare should be individually adapted with the aim to restore knee joint stability and function. Complications such as arthrofibrosis, peroneal nerve palsy, compartment syndrome, postoperative infection and recurrent instability can occur. In the long term, patients have an increased risk for the development of symptomatic osteoarthritis.

Segmental extraneural lipomatosis of the superficial peroneal nerve: illustrative case.

BACKGROUND: Adipose lesions of nerve are rare tumors that can cause nerve symptoms from either intrinsic or extrinsic compression. OBSERVATIONS: The authors present a case of a patient with a 10-year history of progressive, persistent leg pain and dorsal foot paresthesias/dysesthesias. Imaging revealed several nondistinct nodules of indeterminate significance along the course of the superficial peroneal nerve (SPN). Surgery demonstrated six distinct extraneural lipomas studded on a 10-cm segment of the main SPN and one of its muscular branches in the midleg. The lesions were adherent to the SPN, without an easy dissection plane; therefore, a neurectomy was performed. Histology revealed the nerve was associated with multiple extraneural lipomas with focal evidence of prior trauma. At 4 months postoperatively, the patient's pain had resolved completely, and she was able to resume normal physical activities. LESSONS: The current classification of adipose lesions of nerve includes intraneural and extraneural lipomas and lipomatosis of nerve (fibrolipomatous hamartoma). The unique features of the present case include the discrete and segmental nature of the extraneural lipomas adherent to the nerve. Its etiology is unknown, and the histology would be suggestive of either a traumatic or a degenerative process.