Aims. This study aimed to explore whether intraoperative nerve monitoring can identify risk factors and reduce the incidence of nerve injury in patients with high-riding developmental dysplasia. Patients and Methods. We conducted a historical controlled study of patients with unilateral Crowe IV developmental dysplasia of the hip (DDH). Between October 2016 and October 2017, intraoperative nerve monitoring of the femoral and sciatic nerves was applied in total hip arthroplasty (THA). A neuromonitoring technician was employed to monitor nerve function and inform the surgeon of ongoing changes in a timely manner. Patients who did not have intraoperative nerve monitoring between September 2015 and October 2016 were selected as the control group. All the surgeries were performed by one surgeon. Demographics and clinical data were analyzed. A total of 35 patients in the monitoring group (ten male, 25 female; mean age 37.1 years (20 to 46)) and 56 patients in the control group (13 male, 43 female; mean age 37.9 years (23 to 52)) were enrolled. The mean follow-up of all patients was 13.1 months (10 to 15). Results. The two groups had no significant differences in preoperative data. In the monitoring group, ten nerve alerts occurred intraoperatively, and no neural complications were detected postoperatively. In the control group, six patients had neural complications. The rate of nerve injury was lower in the monitoring group than in the control group, but this did not achieve statistical significance. The degree of leg lengthening was significantly greater in the monitoring group than in the control group. In further analyses, patients who had previous hip surgery were more likely to have intraoperative nerve alerts and postoperative nerve injury. Conclusion. Nerve injury usually occurred during the processes of exposure and reduction. The use of intraoperative nerve monitoring showed a trend towards reduced nerve injury in THA for Crowe IV DDH patients. Hence, we recommend its routine use in patients undergoing leg lengthening, especially in those with previous hip surgery. Cite this article: Bone Joint J 2019;101-B:1438–1446

1. The results of repair of the sciatic nerve and of its main divisions have been analysed in a series of 118 cases, the patients having been under observation for three to eighteen years (average 11·7 years). 2. A result was satisfactory if there was some return of sensibility throughout the autonomous zone (the area of skin supplied exclusively by the damaged nerve) and if the more important muscles of the leg were capable of contraction against gravity and resistance. 3. When the whole of the sciatic nerve is damaged it is necessary to present the results separately for the lateral and medial popliteal divisions. 4. Of forty-seven cases of repair of the medial popliteal nerve 79 per cent showed useful motor and 62 per cent useful sensory recovery. In three out of four cases the correspondence between the degree of motor and of sensory recovery was fairly close. 5. Of seventy-two cases of repair of the lateral popliteal nerve 36 per cent showed useful motor and 74 per cent useful sensory recovery. The latter figure must be regarded with some reserve because sensory "recovery" in the lateral popliteal zone may be due to the ingrowth of nerve fibres from contiguous normally innervated skin. Thus it is not possible to correlate motor and sensory recovery. 6. In eighteen cases of repair of the posterior tibial nerve, there was useful sensory recovery in the sole in twelve. But although there was evidence of recovery in the plantar muscles in eleven cases it was functionally valueless. 7. In repair of the medial popliteal nerve the result was better if suture had been carried out early. In repair of the lateral popliteal nerve there was no evidence that delay was harmful; but the proportion of good results was so low (as judged by motor function alone, sensory recovery being often extraneous) that this exception to a general rule cannot be taken very seriously. 8. Gaps of up to twelve centimetres–estimated after resection of the damaged nerve ends–could be closed without difficulty by the usual technique, and the extent of the gap up to that limit had no influence on the prognosis. The closure of larger gaps, when the knee must be flexed beyond a right angle, is not compatible with good recovery because the post-operative stretching of the nerve causes serious intraneural damage. 9. Nerve grafting has given poor results in repair of the sciatic nerve

We report a case of iatrogenic sciatic nerve injury caused by pre-operative intraneural injection of local anaesthetic at total hip replacement. To our knowledge, this is unreported in the orthopaedic literature. We consider sacral nerve blockade in patients undergoing total hip replacement to be undesirable and present guidelines for the management of peri-operative sciatic nerve injury

1. We have described what happens to patients a number of years after injury of the sciatic nerve or of its divisions; there were 329 who had been under observation for periods ranging from three to eighteen years. The neurological recovery was recorded in every case and, more important, the behaviour of the limb as appreciated by the patient. 2. Although it was generally true that good neurological recovery and good function went together there were remarkable discrepancies. Isolated paralysis of the medial popliteal or of the lateral popliteal nerve was often compatible with good function, though patients with lateral popliteal paralysis usually needed toe-raising apparatus. Even total sciatic paralysis sometimes gave little trouble. 3. Of the various types of injury, clean wounds and traction lesions led to rather better than average return of function. 4. Some degree of pain was present in about half the cases, and over-response–exaggerated and painful response to an ordinary stimulus–was present in one-third of the cases. 5. Repair of the posterior tibial nerve was rarely worth while; no less than eight out of twelve patients with this type of injury exhibited over-response. 6. One-third of the patients showed vasomotor and trophic disorders: coldness of the affected limb, erythema, thinness or pigmentation of the skin, changes in the nails or oedema. 7. Pressure sores were the most serious consequence of sciatic nerve injury and at some time or other were present in 14 per cent of our patients. The cause was deformity rather than insensibility of the sole. 8. Of the various palliative operations Lambrinudi's tarsal arthrodesis gave such disappointing results that we doubt whether the operation is worth doing. Tenodesis, revived as a time-saving expedient during the war, was a failure. For lateral popliteal paralysis anterior transplantation of tibialis posterior is excellent. 9. Amputation was done in only ten cases. When it was performed for fixed deformity with secondary ulceration the result was satisfactory. When it was done because of pain there was no relief. Amputation is, therefore, avoidable provided that vigorous steps are taken to prevent or correct deformity; it should not be done for the relief of pain

Injuries to the sciatic nerve are an occasional complication of surgery to the hip and acetabulum, and traction is frequently the causative mechanism. In vitro and animal experiments have shown that increased tensile strain on peripheral nerves, when applied for prolonged periods, impairs nerve function. We have used video-extensometry to measure strain on the human sciatic nerve during total hip replacement (THR). Ten consecutive patients with a mean age of 72 years undergoing primary THR by the posterior approach were recruited, and strains in the sciatic nerve were measured in different combinations of flexion and extension of the hip and knee, before dislocation of the hip. Significant increases (p = 0.02) in strain in the sciatic nerve were observed in flexion of the hip and extension of the knee. The mean increase was 26% (19% to 30%). In animal studies increases of this magnitude have been shown to impair electrophysiological function in peripheral nerves. Our results suggest that excessive flexion of the hip and extension of the knee should be avoided during THR

The purpose of this study was to establish whether exploration and neurolysis is an effective method of treating neuropathic pain in patients with a sciatic nerve palsy after total hip replacement (THR). A total of 56 patients who had undergone this surgery at our hospital between September 1999 and September 2010 were retrospectively identified. There were 42 women and 14 men with a mean age at exploration of 61.2 years (28 to 80). The sciatic nerve palsy had been sustained by 46 of the patients during a primary THR, five during a revision THR and five patients during hip resurfacing. The mean pre-operative visual analogue scale (VAS) pain score was 7.59 (2 to 10), the mean post-operative VAS was 3.77 (0 to 10), with a resulting mean improvement of 3.82 (0 to 10). The pre- and post-neurolysis VAS scores were significantly different (p < 0.001). Based on the findings of our study, we recommend this form of surgery over conservative management in patients with neuropathic pain associated with a sciatic nerve palsy after THR. Cite this article: Bone Joint J 2013;95-B:20–2

Injury to the sciatic nerve following closed manipulation of a dislocated total hip replacement is rare. We present such a case in an elderly patient with partial recovery following exploration and release of the nerve

Traction injury to the sciatic nerve can occur during hamstring lengthening. The aim of this study was to monitor the influence of hamstring lengthening on conduction in the sciatic nerve using evoked electromyography (EMG). Ten children with spastic cerebral palsy underwent bilateral distal hamstring lengthening. Before lengthening, the evoked potential was recorded with the patient prone. During lengthening, it was recorded with the knee flexed to 90°, 60° and 30°, and at the end of lengthening with the hip and knee extended. In all patients, the amplitude of the evoked EMG gradually decreased with increasing lengthening. The mean decrease with the knee flexed to 60° was 34% (10 to 77), and to 30°, 86% (52 to 98) compared with the pre-lengthening amplitude. On hip extension at the end of the lengthening procedure, the EMG returned to the pre-lengthening level. Monitoring of the evoked EMG potential of the sciatic nerve during and after hamstring lengthening, may be helpful in preventing traction injury

We present simple but effective retractors used in pairs to expose the sciatic notch during Salter innominate osteotomy. We have found them to be useful for a wide range of procedures requiring similar exposure. We present them here in tribute to the memory of the designer Mercer Rang

We describe a patient with a painful sciatic neuropathy after total hip arthroplasty. Treatment was confined to neuroleptic and analgesic agents until neurolysis at seven years abolished pain and restored function

We describe a 47-year-old woman with sciatic neuropathy caused by compression of the sacral plexus by posterior shift of the uterus

We present the case of a 63-year-old woman who sustained an acrylic cement burn of the sciatic nerve at hip replacement. She was treated by resection of the damaged segment and grafting. Electron microscopy showed that the nerve was nearly normal 1 cm from the cement margin indicating that this is a safe level for resection

Pain in the distribution of the sciatic nerve is common in the elderly. In the presence of a long-standing joint replacement, consideration should be given as to whether compression might be due to an extraspinal cause. We present three women, in whom a mass of wear debris from a previous total hip replacement caused compression of the sciatic nerve posterior to the hip. The symptoms were relieved immediately following operation

Experiments have shown that the tension of the sciatic nerve roots is increased when the posterior tibial nerve is pressed upon in the popliteal space. A refinement of the straight leg raising test, based on this observation, is described

We describe a patient in whom an initially intact sciatic nerve became rapidly encased in heterotopic bone formed in the abductor compartment after reconstruction of the posterior wall of the acetabulum following fracture. Prompt excision and neural release followed by irradiation and administration of indometacin resulted in a full neurological recovery and no recurrence 27 months later

Severe leg pain in a patient after total hip replacement was found to be caused by compression of the sciatic nerve by methylmethacrylate cement which had leaked from the acetabulum during fixation of the acetabular cup. The pain persisted for six years but was immediately relieved by removal of the cement mass

The right sciatic nerve of 50 one-month-old male rats was cut under general anaesthesia. Groups of animals were sacrificed at intervals of up to 12 weeks after operation and the length of the femora, tibiae and first and fifth metatarsals were measured with a caliper accurate to 0.05 mm. From the first week, both metatarsals were between 3% and 5% shorter on the denervated side, but there was no further increase of the discrepancy. The femora were less than 1% longer in the denervated limb at the second and eighth week. No difference was found between the lengths of the tibiae. The various factors which could possibly be responsible for these findings are discussed

1. Between 1936 and 1945, 525 patients with sciatic pain were treated at the Princess Elizabeth Orthopaedic Hospital, Exeter. Of these, 225 had neurological signs and they were selected for review; 147 were traced. 2. Of these, 123 were treated by means of plaster jackets and twenty-four were treated by other methods. The late results of treatment in the two groups were about the same, roughly one-third being "cured," one-third "relieved," and one-third "not relieved.". 3. Nevertheless examination of the immediate results suggests that protection by means of a plaster jacket had at least a palliative effect, relieving acute symptoms and allowing early rehabilitation. Moreover it should be emphasised that in limiting the investigation to cases of sciatica with evidence of nerve root pressure only the more severe cases have been included. 4. Permanent relief after immobilisation in plaster was greatest when the duration of symptoms was short, and when the patient was treated during his first attack. It was least in patients who showed all three signs of nerve root pressure—diminished ankle jerks, hypo-aesthesia, and muscle hypotonicity. 5. Absence of tendon reflexes due to nerve root pressure, and areas of hypo-aesthesia, tend to remain permanently; but diminution of reflexes and loss of muscle power may recover

An orientated substratum has been implicated in the development and regeneration of axons and synapses. We prepared a basement membrane matrix from autogenous striated muscle, used it to repair the sciatic nerve in rats, then investigated the results by histology and electrophysiology. When treated grafts were coaxially aligned with the nerve fascicles functional recovery appeared within 30 days, with good growth of axons into the distal nerve. Grafts with myotubes at right angles to the nerve fascicles supported nerve regeneration but at a slower rate. Grafts of coaxially aligned but untreated muscle allowed axon penetration only through naturally degenerated muscle fibres, with minimal axon penetration of the distal nerve. It is concluded that in the rat a treated graft with correctly orientated empty myotubes can facilitate and guide the regeneration of peripheral nerve after injury and so lead to recolonisation of the distal stump with functional recovery

1. The risk of injury to the sciatic nerve during closed ischio-femoral arthrodesis by nail and graft has been assessed on the basis of clinical evidence and of anatomical studies in the living and in cadavers. 2. The margin of safety for the nerve is nearly always small. 3. The risk of injury to the nerve is prohibitive when there is marked deformity or hypoplasia of the pelvis. The risk is also increased when the buttock is compressed against the table and, because of the technical difficulties that are entailed, when the hip is in marked flexion. The risk is probably greater in children than in adults. 4. In properly selected cases in which none of these adverse factors is present it is submitted that the risk of nerve injury can be eliminated by proper attention to surgical technique and by the observance of certain definite precautions. 5. When there is doubt in the surgeon's mind about his ability to complete the operation without injuring the nerve the closed technique should be abandoned in favour of the open posterior approach