Sciatic nerve monitoring during revision total hip arthroplasty.

This study presents a simple method of intraoperative sciatic nerve monitoring during revision total hip arthroplasty (THA), utilizing intraoperative, somatosensory evoked potentials. Using this method, the sciatic nerve was protected when surgical correction of shortened limb length was necessary during revision THA. Twenty-three revision THAs were performed using intraoperative sciatic nerve monitoring. No postoperative peripheral nerve complications occurred, with an average increase of 18 mm in leg length, ranging from 6 mm to 43 mm.     

Monitoring of somatosensory and motor evoked potentials during open reduction and internal fixation of pelvis and acetabular fractures

Monitoring of motor and somatosensory evoked potentials provides instantaneous intraoperative assessment of a patient's neurologic status. Monitoring of the sciatic nerve through motor and somatosensory evoked potentials can be used during open reduction and internal fixation of pelvic and acetabular fractures. A review of 12 pelvic and acetabular fractures treated with open reduction and internal fixation was conducted and assessed with a combination of intraoperative motor and somatosensory evoked potential monitoring. Results revealed intraoperative motor evoked potential monitoring was 100% sensitive and 100% specific in predicting postoperative sciatic nerve deficits, whereas somatosensory evoked potentials were not accurate in predicting postoperative sciatic nerve deficits. Combined monitoring of the sciatic nerve with motor and somatosensory evoked potentials is beneficial at predicting postoperative sciatic nerve deficits during open reduction and internal fixation of pelvic and acetabular fractures.     

Somatosensory evoked potential monitoring in the surgical management of acute acetabular fractures

Fifty patients undergoing acute acetabular fracture surgery had intraoperative somatosensory evoked potential (SSEP) monitoring. Group II, the final 38 patients, in addition had independent neurological evaluation preoperatively and postoperatively. Thirteen of 50 patients (26%) had preoperative sciatic nerve involvement. Fourteen of 50 patients (28%) developed significant intraoperative SSEP changes (decreased amplitude, increased latency). When the nerve was involved preoperatively (high-risk group), changes in SSEP occurred in 60% of patients. Iatrogenic sciatic/peroneal neuropraxia occurred in only one patient in the series (2%), and this resolved within 4 months. These results compare favorably to the incidence of 5-18% reported in the literature. We conclude SSEP is feasible and should be used in the operative treatment of acetabular fractures, especially the posterior fracture patterns and for those in the high-risk group.     

Dissociation of modular total hip arthroplasty at the femoral head-neck interface after loosening of the acetabular shell following hip dislocation

Modular component dissociation is a potential problem of current modular total hip arthroplasty (THA) systems. We describe a case of dissociation of the modular THA at the femoral head-neck interface after loosening of the acetabular shell during closed reduction for posterior dislocation of THA. The causes of this dissociation and acetabular shell loosening are discussed. Successful treatment was provided with surgical revision of the acetabular and the femoral head components. The present case serves as a graphic reminder that the acetabular shell overhanging the acetabular bone must be avoided when implanting modular THA components.     

Total hip arthroplasty for failed treatment of acetabular fractures: a 5-year follow-up study

Total hip arthroplasty (THA) remains an available surgical option for failed treatment of acetabular fractures. We retrospectively analyzed 53 patients who underwent THA because of failed treatment of acetabular fractures. The mean duration of follow-up monitoring was 64 months (range, 32-123 months) in 49 patients. The average Harris hip score increased from 49.5 before surgery to 90.1 at the latest follow-up examination. Postoperative complications included 1 dislocation, 3 sciatic nerve injuries, and 3 class III instances of heterotopic ossification. There was only 1 revision due to aseptic loosening of the acetabular and femoral component. Despite the technically demanding nature of the procedure, the results of acetabular reconstruction are encouraging in these patients; complication rates are low, and patient satisfaction level is high.     

Intraoperative somatosensory evoked potential monitoring of pelvic and acetabular fractures.

The efficacy of intraoperative somatosensory evoked potential (SSEP) monitoring was evaluated in the surgical management of 82 patients with pelvic and acetabular fractures. The injuries consisted of 45 acetabular fractures, 30 pelvic ring disruptions, and seven combined injuries. Preoperative neurological deficits were recorded in 34% of the study group (29% of those with an acetabular fracture and 47% of those with a pelvic ring injury). Three patients sustained an iatrogenic sciatic nerve injury during the study period (all of which were documented in the first 40 cases). Two patients sustained an exacerbation of an existing sciatic nerve injury. In the group of pelvic fractures, hazardous parts of the exposure, reduction, and fixation were identified by the SSEP monitoring. Removal of the provocative stimulus by the surgeon led to reversal of the SSEP abnormalities, and none of this group of patients sustained an iatrogenic injury. When the intraoperative SSEP changes were noted during an acetabular fracture fixation, immediate attempts were made to relieve the excessive tension on the sciatic nerve by replacing or removing a retractor, flexing the knee, extending the hip, or dividing the femoral insertion of the gluteus maximus. None of the SSEP changes were associated with the lacerative injury to the sciatic nerve. For the method to be clinically effective in reducing the incidence of neurological deficit, even subtle changes in the SSEP tracing must be recognized immediately by the neurophysiologist so that a corresponding corrective measure can be rapidly undertaken by the surgeon to remove the offending stimulus.     

Delayed neuropathy of the sciatic nerve after total hip replacement with an acetabular reinforcement ring

AIM: Lesions of the sciatic or femoral nerve after THR are typical complications. Delayed neuropathies of the sciatic or femoral nerve are rare conditions. CASE REPORT: We report the case of a delayed neuropathy of the sciatic nerve after THR with reconstruction of the acetabulum with an acetabular reinforcement ring. After electrophysiologic evaluation we performed a revision of the sciatic nerve. Intraoperatively we found an impingement of the sciatic nerve between the dorsal aspect of the acetabular reinforcement ring and scar tissue. After revision of the nerve, resection of the scar tissue and interposition of a fat pad the patient was out of any complaints but reported some sensory deficits of the first toe. CONCLUSION: Using acetabular reinforcement rings for reconstruction of acetabular defects care has to be taken of the correct position. In anatomically cramped positions a protruding of the dorsal edge of the ring may cause a lesion of the sciatic nerve.     

Sciatic nerve compression by an extrapelvic cyst secondary to wear debris after a cementless total hip arthroplasty: A case report and literature review

INTRODUCTIONPolyethylene (PE) wear debris after total hip arthroplasty (THA) may cause formation of a soft tissue mass due to inflammatory reaction. To the best of our knowledge we report the first case in whom the diagnosis was made after examination of the hip, pelvis and lumbar spine with detailed radiological methods and the plain radiographs showed no signs of loosening of the THA.PRESENTATION OF CASEWe report a 52 years-old woman who presented with a cyst causing sciatic irritation in her gluteal region due to wear debris after THA. Magnetic resonance imaging (MRI) was useful in detecting the cyst. Resolution of the cyst occured after subtotal cystectomy and revision of the acetabular components.DISCUSSIONAlthough plain radiographs can show signs of the underlying pathology; such as osteolysis, loosening of the components and wear of the PE liner, they are unable to detect cystic lesions. Cystic lesions may be an early sign of wear debris.CONCLUSIONThis case shows us that sciatic neuropathy with no evidence of nerve root impingement on lumbar MRI in a patient with THA requires also examination of the hip and pelvis with detailed radiological methods, such as MRI, in addition to plain radiography. Removal of the source of debris via revision surgery following subtotal cystectomy leads to the resolution of the remaining portion of the cyst and also relief of the symptoms of sciatic nerve compression.     

Dual Mobility for Monoblock Metal-on-Metal Revision—Is It Safe?

BackgroundRevision of monoblock metal-on-metal (MoM) total hip arthroplasty (THA) is associated with high complication rates. Limited revision by conversion to a dual mobility (DM) without acetabular component extraction may mitigate these complications. However, the concern for polyethylene wear and osteolysis remains unsettled. This study investigates the results of DM conversion of monoblock MoM THA compared to formal acetabular revision.MethodsOne hundred forty-three revisions of monoblock MoM THA were reviewed. Twenty-nine were revisions to a DM construct, and 114 were complete revisions of the acetabular component. Mean patient age was 61, 54% were women. Components used, acetabular cup position, radiographic outcomes, serum metal ion levels, and HOOS Jr clinical outcome scores were investigated.ResultsAt 3.9 years of follow-up (range 2-5), there were 2 revisions (6.9%) in the DM cohort, 1 for instability and another for periprosthetic fracture. Among the formal acetabular revision group there was a 20% major complication rate (23/114) and 16% underwent revision surgery (18/114) for aseptic loosening of the acetabular component (6%), deep infection (6%), dislocation (4%), acetabular fracture (3%), or delayed wound healing (6%). In the DM cohort, there were no radiographic signs of aseptic loosening, component migration, or polyethylene wear. One DM patient had a small posterior metadiaphyseal femur lesion that will require close monitoring. There were no other radiographic signs of osteolysis. There were no clinically significant elevations of serum metal ion levels. HOOS Jr scores were favorable.ConclusionLimited revision with conversion to DM is a viable treatment option for failed monoblock MoM THA with lower complication rates than formal revision. Limited revision to DM appears to be a safe option for revision of monoblock MoM THA with a cup in good position and an internal geometry free of sharp edges or articular surface damage. Longer follow-up is needed to demonstrate any potential wear implications of these articulations.     

Optimizing leg length and cup position: A surgical navigation tool

Inaccurate component placement during total hip arthroplasty (THA) can have significant and costly consequences. Malpositioning of the acetabular cup components can lead to dislocation and revision surgery, while postoperative discrepancies in leg length – the primary driver for litigation against orthopaedic surgeons – can lead to biomechanical imbalances, causing chronic low back pain. Current methods for monitoring these parameters intraoperatively rely on manual methods such as tissue tensioning or on the surgeon's experience, both of which are subject to inaccuracies. Computer-assisted navigation, while currently used in only a small percentage of THA procedures, is an emerging technology that has the potential to improve the accuracy with which surgeons place components during THA by providing real-time, intraoperative data. One innovative navigation system – Intellijoint HIP® (Intellijoint Surgical, Waterloo, ON) – has demonstrated its accuracy, time-neutrality, safety and effectiveness in several clinical studies and has the potential to improve outcomes and reduce re-admissions and revision during both primary and revision THA.     

Total Hip Arthroplasty in Patients With Osteopetrosis

BackgroundOsteopetrosis is an inherited bone disease associated with high risk of osteoarthritis and fracture non-union, which can lead to total hip arthroplasty (THA). Bone quality and morphology are altered in these patients, and there are limited data on results of THA in these patients. The goals of this study were to describe implant survivorship, clinical outcomes, radiographic results, and complications in patients with osteopetrosis undergoing primary THA.MethodsWe identified 7 patients (9 hips) with osteopetrosis who underwent primary THA between 1970 and 2017 utilizing our total joint registry. The mean age at index THA was 48 years and included two males and five females. The mean follow-up was 8 years.ResultsThe 10-year survivorship free from any revision or implant removal was 89%, with 1 revision and 1 resection arthroplasty secondary to periprosthetic femoral fractures. The 10-year survivorship free from any reoperation was 42%, with 4 additional reoperations (2 ORIFs for periprosthetic femoral fractures, 1 sciatic nerve palsy lysis of adhesions, 1 hematoma evacuation). Harris hip scores significantly increased at 5 years (P = .04). Five hips had an intraoperative acetabular fracture, and 1 had an intraoperative femur fracture. All postoperative femoral fractures occurred in patients with intramedullary diameter less than 5 mm at a level 10 cm distal to the lesser trochanter.ConclusionPrimary THA in patients with osteopetrosis is associated with good 10-year implant survivorship (89%), but a very high reoperation (58%) and periprosthetic femoral fracture rate (44%). Femoral fractures appear associated with smaller intramedullary diameters.     

Treatment options for chronic pelvic discontinuity

Chronic pelvic discontinuity is a distinct and unique challenge seen during revision total hip arthroplasty (THA) in which the superior ilium is separated from the inferior ischiopubic segment through the acetabulum, rendering the anterior and posterior columns discontinuous. The operative management of acetabular bone loss in revision THA is one of the most difficult challenges today. Common treatment options include cage reconstruction with bulk acetabular allograft, custom triflange acetabular component, a cup-cage construct, jumbo acetabular cup with porous metal augments, or acetabular distraction with a porous tantalum shell with or without modular porous augments.     

Acetabular Total Hip Arthroplasty Revision: A Summary of Operative Factors,Outcomes, and Comparison of Approaches

BackgroundRevision total hip arthroplasty (THA) presents a greater risk to patients than primary THA, and surgical approach may impact outcomes. This study aimed to summarize acetabular revisions at our institution and to compare outcomes between direct anterior and posterior revision THA.MethodsA series of 379 acetabular revision THAs performed from January 2010 through August 2022 was retrospectively reviewed. Preoperative, perioperative, and postoperative factors were summarized for all revisions and compared between direct anterior and posterior revision THA.ResultsThe average time to acetabular revision THA was 10 years (range, 0.04 to 44.1), with mechanical failure (36.7%) and metallosis (25.6%) being the most prevalent reasons for revision. No differences in age, body mass index, or sex were noted between groups. Anterior revision patients had a significantly shorter length of stay (2.2 versus 3.2 days, P = .003) and rate of discharge to a skilled nursing facility (7.5 versus 25.2%, P = .008). In the 90-day postoperative period, 9.2% of patients returned to the emergency department (n = 35) and twelve patients (3.2%) experienced a dislocation. There were 13.2% (n = 50) of patients having a rerevision during the follow-up period with a significant difference between anterior and posterior approaches (3.8 versus 14.7%, respectively, P = .049).ConclusionThis study provides some evidence that the anterior approach may be protective against skilled nursing facility discharge and rerevision and contributes to decreased lengths of stay. We recommend surgeons select the surgical approach for revision THA based on clinical preferences and patient factors.     

Does Ischial Screw Fixation Improve Mechanical Stability in Revision Total Hip Arthroplasty?

Ischial screw fixation, albeit technically challenging, is postulated to provide additional mechanical stability in revision total hip arthroplasty (THA). Hemipelvis specimens were prepared to simulate revision THA, and an acetabular component with supplemental screw fixation was implanted. Three configurations were tested: 2 dome screws alone, 2 dome screws plus an additional screw within the dome, and 2 dome screws plus an ischial screw. Force displacement data were acquired during mechanical testing. An increase in mechanical stability was observed in acetabular components with supplemental screw fixation into either the posterior column or ischium (P ≤ .031) compared to isolated dome fixation. In addition, supplemental ischial screw fixation may provide a modest advantage over a screw placed posteroinferiorly within the acetabular dome during revision THA.     

Bulk femoral-head autografting in uncemented total hip arthroplasty for acetabular dysplasia: results at 8 to 11 years follow-up

Acetabular dysplasia causes difficulty in achieving adequate coverage of the acetabular component during total hip arthroplasty (THA). Bulk femoral-head autografting is one technique that has been used to achieve better coverage of the acetabular component. Long-term follow-up studies have shown a significant failure rate when this technique has been used in conjunction with a cemented acetabular component; however, with uncemented components, early results have been encouraging. In our study, 15 patients with acetabular dysplasia underwent uncemented THA, during which bulk femoral-head autografts were used. At an average follow-up of 10 years, no cases required revision, and radiologically, the bone graft had united. Our results support the use of bulk femoral-head autografting in patients with acetabular dysplasia requiring hip arthroplasty.     

髋臼后壁骨折伴髋关节后脱位与坐骨神经损伤的临床分析

目的 探讨髋臼后壁骨折伴髋关节后脱位合并坐骨神经损伤的创伤机制、类型和预后关系.方法 笔者收治髋臼后壁骨折伴髋关节后脱位合并坐骨神经损伤21例,在骨折内固定时,均行坐骨神经探查术,按MCRR标准评定神经功能恢复情况.结果 21例在术后24个月内,神经均有不同程度的功能恢复,优11例,良9例,可1例,优良率为95.2%.本组无一例出现医源性损伤.结论 髋臼后壁骨折伴髋关节后脱位常合并坐骨神经损伤者,在骨折内固定时应探查神经,结合损伤性质和程度,采取相应疗措施,有利于正确判断预后和恢复神经功能.     

Causes of Revision in Young Patients Undergoing Total Hip Arthroplasty

BackgroundThe purpose of this study was to identify reasons for revision of total hip arthroplasty (THA) in patients who underwent primary THA at or before the age of 35 years. We hypothesized that the reasons for revision in younger patients would be different from the general older population of patients undergoing THA because of the differences in diagnoses, complexity of deformities, and differences in activity level.MethodsData for 108 hips in 82 patients who underwent primary THA at our institution before the age of 35 years from 1982-2007 and subsequently underwent revision THA were reviewed. Operative reports and clinic notes were reviewed to determine baseline characteristics, reason for revision, timing of revision, and components revised.ResultsThe mean age at index surgery was 25.4 years, and mean time from index to revision surgery was 10.1 years. The most common preoperative diagnoses included avascular necrosis, juvenile idiopathic arthritis, developmental dysplasia of the hip, and posttraumatic arthritis. The most common reasons for revision were acetabular loosening (30.1%), femoral loosening (23.7%), and polyethylene wear (24.7%). 8.3% of patients underwent primary THA with highly cross-linked polyethylene, while the remainder of the patients underwent THA when conventional polyethylene was used. There was no statistically significant association between which component(s) were revised and initial fixation (ie cemented or uncemented prosthesis) (P = .26).ConclusionCauses of revision in this population appear to differ from the general THA population. In young patients, acetabular loosening, femur loosening, and polyethylene wear were the most common causes of revision. Instability and infection were less common compared with literature reports of causes of revision in older patients. Findings in this study may be useful in counseling young patients undergoing THA, though results were likely influenced by the use of conventional rather than highly cross-linked polyethylene in this cohort.     

Intraoperative electromyographic monitoring during periacetabular osteotomy

Periacetabular osteotomy has become the procedure of choice in many centers for the treatment of symptomatic hip dysplasia. Intraoperative real-time nerve monitoring has been advocated during acetabular fracture repair and complex total hip arthroplasties to prevent iatrogenic sciatic nerve injury. To the authors' knowledge there is no information concerning the use of intraoperative electromyographic monitoring during periacetabular osteotomy. The purpose of the current study was to investigate the use of intraoperative continuous electromyographic monitoring during periacetabular osteotomy in a relatively large consecutive series of patients as a mechanism to prevent nerve injury during surgery and as a prognostic indicator of neurologic function after periacetabular osteotomy. From September 1992 to July 1999, 140 consecutive periacetabular osteotomies were done in 127 patients at the authors' institution. There were 96 females and 31 males, with an average age of 32 years at the time of surgery. All patients had intraoperative electromyographic monitoring of femoral and sciatic innervated muscles. All patients were followed up for a minimum of 1 year, until complete resolution of neurologic deficits, or both. Thirty-six patients (26%) had abnormal electromyographic activity recorded during surgery. Seven patients (5%) had peroneal nerve deficits postoperatively including extensor hallucis longus and tibialis anterior weakness with loss of sensation in the first web space. Abnormal electromyographic activity was observed intraoperatively in five of the seven patients with postoperative deficits. Six of the seven injuries resolved completely. One patient with intraoperative electromyographic activity (0.7%) had a postoperative foot drop that persisted for greater than 1 year. There were no femoral, tibial, or obturator nerve deficits observed. Electromyographic monitoring appears to provide prediction of postoperative neurologic deficit.