Osteoarthritis (OA) is a highly prevalent degenerative joint disorder characterized by joint pain and physical disability. Aberrant subchondral bone induces pathological changes and is a major source of pain in OA. In the subchondral bone, which is highly innervated, nerves have dual roles in pain sensation and bone homeostasis regulation. The interaction between peripheral nerves and target cells in the subchondral bone, and the interplay between the sensory and sympathetic nervous systems, allow peripheral nerves to regulate subchondral bone homeostasis. Alterations in peripheral innervation and local transmitters are closely related to changes in nociception and subchondral bone homeostasis, and affect the progression of OA. Recent literature has substantially expanded our understanding of the physiological and pathological distribution and function of specific subtypes of neurones in bone. This review summarizes the types and distribution of nerves detected in the tibial subchondral bone, their cellular and molecular interactions with bone cells that regulate subchondral bone homeostasis, and their role in OA pain. A comprehensive understanding and further investigation of the functions of peripheral innervation in the subchondral bone will help to develop novel therapeutic approaches to effectively prevent OA, and alleviate OA pain. Cite this article: Bone Joint Res 2022;11(7):439–452

This is a retrospective study of 612 cases of iatropathic injury to peripheral nerves seen in one tertiary referral unit between 1991 and 1998. A total of 291 patients was subsequently operated on to explore the nerve lesion. The most common presenting symptom was pain, which often masked underlying loss of function. The delay in diagnosis was up to 40 months. The findings at operation were analysed according to the type of nerve damaged, the nature of the injury and the referring specialty. Some of the more common causal operations and procedures are discussed. Preventive measures are listed, and early diagnosis and treatment are recommended

Multiple tumours of peripheral nerves are often seen in patients with neurofibromatosis of type 1 or 2. Multiple schwannomas may occur without other manifestations of neurofibromatosis. We have reviewed 12 patients with multiple schwannomas arising from peripheral lesions who did not fulfil the criteria for either type of neurofibromatosis. Four had spinal and one an intracranial lesion in addition to the peripheral tumours. Two patients had one and three café-au-lait spots, respectively, and another had a probable family history. The largest tumours were 45 to 250 mm in size. Three patients had been referred as having von Recklinghausen’s disease. The large size of tumours, the difficulties of histological diagnosis on biopsy, and the confusion with neurofibromatosis can lead to overtreatment. Malignant change seldom, if ever, occurs in patients with multiple schwannomas

Between 1988 and 1998, a total of 12 patients (6 men and six women, of average age 36 years) underwent surgery for schwannoma of the peripheral nerves of the upper extremity. The incidence according to the involved nerve was analyzed and the follow-up results and complications after surgical treatment were reviewed. The median nerve was most frequently involved (6 cases), followed by the ulnar nerve (4 cases) and the radial nerve (2 cases). The average duration of symptoms was 2 years (3 months-8 years). Pain or painful paresthesias were usually the main complains. None of the patients suffered from Recklinhausen’s disease. Magnetic resonance imaging is the preferred exploration technique, particularly useful in case of deep tumor. EMG studies were carried out in all patients. Preservation of nerve continuity is the underlying goal of the therapeutic strategy. Marginal excision was performed in all cases. The tumors were extricable displacing the nerve fiber bundles without penetrating into the bundle itself and it was possible thus to be resected without interrupting the nerve continuity. Postoperatively, 7 patients were pain free, while 5 improved. Neurological deficits were favourably influenced by the operation. Out of 4 patients with motor deficits 3 had complete and 1 had partial recovery. Three out of 6 patients with sensory deficits had complete recovery, 2 remained unchanged, while 1 worsened. One patient developed new motor and another one new sensory deficits. New deficits developed predominantly in patients with large tumorsor longstanding symptoms. There was no reccurence or malignant transformation until the average of 52 months of follow-up

Purpose of the study: Benign tumors of peripheral nerves are exceptional. Schwannomas predominate. Most tumors are revealed by tumefaction or pain over a nerve trajectory. The risk of degeneration is very low. Magnetic resonance imaging is the exploration of choice. The risk of sequelae or recurrence must nevertheless be determined with precision. We reviewed our experience with 93 benign tumors of peripheral nerves to search for factors predictive of prognosis. Material and methods: This retrospective analysis included patients seen between 1979 and 2004. We collected a series of 89 patients, 41 women and 48 men, mean age 48 years, age range 18–80, with 93 benign tumors. Mean time from symptom onset (pain) to diagnosis was 20 months. The patients consulted for pain (n=78), presence of a mass (n=79) or both (n=66). Percussion produced paresthesia in 54 patients. Pre-operative magnetic resonance imaging was available for 45 patients. The same surgeon performed nerve microsurgery in all patients. A prior procedure had been performed in another institution for 23 patients. The tumors were: schwannoma (n=74), neurofibroma (n=14), plexiform neurofibroma (n=3), angiolipoma (n=1) and intranervous lipoma (n=1). Mean tumor size was 31 mm (range 7–120 mm). Tumors were located in the brachial plexus (n=13), the upper limb (n=29), the trunk (n=1) and the lower limb (n=50). Complete resection was achieved in 83 cases, with removal of a non-stimulatable fascicle in 50 cases and a motor fascicle in. 4. Nerve repair was required for 11 cases: 5 by direct suture and 6 with grafts. Resection was impossible for 4 tumors treated by neurolysis, decompressive epineu-rotomy, biopsy and interfascicular dissection. Results: Mean follow-up was 96 months (range 3–300). Outcome was very good for 42, good for 25, fair for 8 and poor for 5 (all seen secondarily). Nine patients were lost to follow-up. There were no cases of recurrence. Discussion: Microsurgical procedures are necessary for resection of nerve tumors in order to preserve the fascicles and thus function. Unresectable tumors and secondary grafts yield les satisfactory results, in our series and in the literature. Similarly, the duration of the symptoms and the size of the tumor increase the risk of operative difficulty and sequelae. Despite high-performance imaging techniques, surgery is the only sure way to establish certain diagnosis

Solitary tumors of the peripheral nerves are uncommon and found to be benign in 90 p. 100 of the cases. They develop from the elements constituting the nerve and are generally schwannomas (80 p. 100). Other tumors are much more exceptional and exhibit wide histological variability. The diagnosis of a tumor of the peripheral nerve must be envisaged for all cases with tumefaction or pain on the path of a nerve exacerbated at percussion. Magnetic resonance imaging is the preferred exploration technique, particularly useful in case of a deep tumor. Preservation of nerve continuity is the underlying goal of the therapeutic strategy, irrespective of the type of tumor. Extricable tumors are to be distinguished from inextricable tumors. Extricable tumors (schwannomas, intranervous lipomas) displace nerve fiber bundles without penetrating into the bundle itself and can thus be resected without interrupting nerve continuity. Prognosis is excellent if no recurrence or degeneration occurs. In case of persistent symptoms, a new exploration may be required to search for other localized tumor(s) unperceived at the first procedure. Inextricable tumors (solitary neurofibromas, hemangiomas of the Schwann sheath, neurofibrolipomas) infiltrate the structural elements of the nerve fibers making complete excision impossible without altering the nerve fibers. Epineurotomy (associated with an interfascicular biopsy for pathology examination) allows decompression and can often provide symptom relief although moderate paresthesia may persist. Patients must be informed of this possibility prior to surgery. Any recent and rapidly evolving modification in the clinical findings is suggestive of recurrence and should be followed by revision exploration. Malignant degeneration has not been observed in solitary tumors to our knowledge. Our own experience with 51 cases is generally in agreement with reports in the literature

Locognosia, the ability to localise touch, is one aspect of tactile spatial discrimination which relies on the integrity of peripheral end-organs as well as the somatosensory representation of the surface of the body in the brain. The test presented here is a standardised assessment which uses a protocol for testing locognosia in the zones of the hand supplied by the median and/or ulnar nerves. The test-retest reliability and discriminant validity were investigated in 39 patients with injuries to the median or ulnar nerve. Intraclass correlation coefficients were used to calculate the test-retest reliability. Discriminant validity was assessed by comparing the injured with the unaffected hand. Excellent test-retest reliability was demonstrated for the injuries to the median (intraclass correlation coefficient 0.924, 95% confidence interval 0.848 to 1.00) and the ulnar nerves (intraclass correlation coefficient 0.859, 95% confidence interval 0.693 to 1.00). The magnitude of the difference in scores between affected and unaffected hands showed good discriminant validity. For injuries to the median nerve the mean difference was 11.1 points (1 to 33; . sd. 7.4), which was statistically significant (p < 0.0001, paired t-test) and for those of the ulnar nerve it was 4.75 points (1 to 13.5; . sd. 3.16), which was also statistically significant (paired t-test, p < 0.0001). The locognosia test has excellent test-retest reliability, is a valid test of tactile spatial discrimination and should be included in the evaluation of outcome after injury to peripheral nerves

Purpose: Isolated tumours of the peripheral nerves are exceptional and benign in 90% of the cases. They develop from the constitutive elements of the nerve and correspond to schwannomas in 80% of cases. Other tumours are much more rare and exhibit wide histological variability. Material and methods: Fifty-one patients were reviewed at mean 4.6 years. Forty-one had a resectable tumour: schwannoma (n=39), intranervous lipoma (n=2). Ten an unresectable tumour: solitary neurofibroma (n=5), peri-nervous hemangioma (n=3), neurofibrolipoma (n=2). We detailed the type of lesion, diagnostic elements, and results of complementary explorations. Enucleation was performed for resectable tumours. Epineurotomy for decompression with systematic interfascicular biopsy was performed in the event of an unresectable tumour. Results: Postoperative neurological deficits were exceptional and transient. In a first case, prognosis was excellent due to the absence of recurrence or degeneration. In the second, neurological disorders persisted but decreased (paraesthesia). The course remained stable. Discussion: Our findings are in line with reports in the literature. The diagnosis of nerve tumour should be entertained in the event of tumefaction along a nerve trajectory or if palpation triggers pain. MRI is the most powerful complementary exploration, particularly for deep tumours. The nature of the tumour, its benignity, and the possibility for resection can be suspected on the basis of clinical and complementary findings, but surgery and pathology examination of the surgical specimen are required for confirmation. Preservation of nerve continuity is the key to the therapeutic approach. For resectable tumours, exceptional persistence of symptoms should be followed by a new exploration to search for small unrecognised tumour(s) at the same operative site. For all other cases, recent and rapid changes in the clinical presentation is a sign of recurrence and requires appropriate intervention. To our knowledge, malignant degeneration has never been observed. Conclusion: First-intention resection of a nerve with a nerve tumour is never indicated

We prospectively studied 26 consecutive patients with clinically documented sensory or motor deficiency of a peripheral nerve due to trauma or entrapment using ultrasound, and in 19 cases surgical exploration of the nerves was undertaken. The ultrasonographic diagnoses were correlated with neurological examination and the surgical findings. Reliable visualisation of injured nerves on ultrasonography was achieved in all patients. Axonal swelling and hypoechogenity of the nerve was diagnosed in 15 cases, loss of continuity of a nerve bundle in 17, the formation of a neuroma of a stump in six, and partial laceration of a nerve with loss of the normal fascicular pattern in five. The ultrasonographic findings were confirmed at operation in those who had surgery.

Ultrasound may be used for the evaluation of peripheral nerve injuries in the upper limb. High-resolution ultrasound can show the exact location, extent and type of lesion, yielding important information that might not be obtainable by other diagnostic aids.

In this study, we discuss 68 cases in which peripheral nerve trunks were inadvertently divided by surgeons. Most of these accidents occurred in the course of planned operations. Delay in diagnosis and in effecting repair was common. We list the nerves particularly at risk and the operations in which special care is needed. We recommend steps to secure prompt diagnosis and early treatment.

Introduction and aims

We present a series of patients who have had secondary reconstruction of war injuries to the upper and lower limbs, sustained during the Iraq and Afghanistan conflicts.

Introduction

We present a series of patients who have had secondary reconstruction of war injuries to the upper and lower limbs, sustained during the Iraq and Afghanistan conflicts.

We undertook a retrospective analysis of 306 procedures on 233 patients, with a mean age of 12 years (1 to 21), in order to evaluate the use of somatosensory evoked potential (SSEP) monitoring for the early detection of nerve compromise during external fixation procedures for limb lengthening and correction of deformity. Significant SSEP changes were identified during 58 procedures (19%). In 32 instances (10.5%) the changes were transient, and resolved once the surgical cause had been removed. The remaining 26 (8.5%) were analysed in two groups, depending on whether or not corrective action had been performed in response to critical changes in the SSEP recordings. In 16 cases in which no corrective action was taken, 13 (81.2%, 4.2% overall) developed a post-operative neurological deficit, six of which were permanent and seven temporary, persisting for five to 18 months. In the ten procedures in which corrective action was taken, four patients (40%, 1.3% overall) had a temporary (one to eight months) post-operative neuropathy and six had no deficit.

After appropriate intervention in response to SSEP changes, the incidence and severity of neurological deficits were significantly reduced, with no cases of permanent neuropathy. SSEP monitoring showed 100% sensitivity and 91% specificity for the detection of nerve injury during external fixation. It is an excellent diagnostic technique for identifying nerve lesions when they are still highly reversible.

The concept of non-anatomic reversed arthroplasty is becoming increasingly popular. The design medializes and stabilizes the center of rotation, and lowers the humerus relative to the acromion, and lengthens the deltoid muscle up to 18%. Such a surgically created global distraction of muscles is likely to affect nervous structures. When nerves are stretched up to 5–10%, axonal transport and nerve conduction starts to be impaired. At 8% of elongation, venous blood flow starts to diminish and at 15% all circulation in and out of the nerve is obstructed. [. 1. ] To understand nerve dynamics following reversed arthroplasty, we investigated nerve strain and excursion in a cadaver model. In a formalin-embalmed female cadaver specimen, the brachial plexus en peripheral upper limb nerves were carefully dissected and injected with an iodine containing contrast medium. At the same time 1.2 mm-diameter leaded markers were implanted at topographically crucial via points for later enhanced recognition on CT reconstructions. After the first session of CT scanning a plastic replica of the Delta reversed shoulder prosthesis® was surgically placed followed by re-injection of the plexus with the same solution. The preoperative and the postoperative specimen were studied using a helical CT scan with a 0,5 mm slice increment. The Mimics® (Materialise NV, Belgium) software package was used for visualization and segmentation of CT images and 3D rendering of the brachial plexus and peripheral nerves. After surgery, there was an average increase in nerve strain below physiologically relevant amplitudes. In a few local segments of the brachial plexus an increase in nerve strain exceeding 5–10 % was calculated. The largest increase in strain (up to 19%) was observed in a segment of the medial cord. These results suggest there might be a clinically relevant increase in nerve strain following reversed shoulder arthroplasty