Rafael J. Sierra

A Systematic Approach to the Plain Radiographic Evaluation of the Young Adult Hip

Orthopaedic evaluation of hip pain in the young adult population has undergone a rapid evolution over the past decade1,2. This is in large part due to enhanced awareness of structural hip disorders, including developmental dysplasia of the hip and femoroacetabular impingement1-5. Surgical treatment for these disorders continues to be refined6-9, and our ability to identify patients along the spectrum of disease continues to improve10-15. Yet, despite our advances, obtaining an accurate diagnosis can remain challenging, especially in the setting of mild structural abnormalities. Therefore, radiographic examination is a critical component of the diagnostic evaluation and treatment decision-making process. It is essential that physicians have common and reliable radiographic views as well as parameters for plain radiographic assessment that can serve as a foundation for accurate diagnosis, disease classification, and surgical decision-making. Many different radiographic measurements have been described as indicators of structural disease. In particular, measurements such as the lateral center-edge angle of Wiberg16, the anterior center-edge angle of Lequesne17, the ac-etabular index of depth to width described by Heyman and Herndon18, the femoral head extrusion index19, and the Tonnis angle20 have been used as markers for acetabular dysplasia. Similarly, measurements of acetabular version21, the head-neck offset (initially described by Eijer)3,22, and the alpha angle19 have been used in the diagnosis of femoroacetabular impingement. Nevertheless, there is limited literature that provides comprehensive information regarding the details of radiographic evaluation in the young patient with hip symptoms. This paper summarizes the recommendations of the ANCHOR (Academic Network for Conservational Hip Outcomes Research) study group regarding the most important aspects of radiographic technique and image interpretation to evaluate the symptomatic, skeletally mature hip.

Osteonecrosis of the femoral head.

New cases of osteonecrosis of the femoral head in the United States number between 10,000 and 20,000 per year. This disease usually affects patients in their late 30s and early 40s. Although a number of authors have related specific risk factors to this disease, its etiology, pathogenesis, and treatment remain a source of considerable controversy. This disorder has been associated with corticosteroid use, substance abuse, and various systemic medical conditions. Either direct damage to osteocytes (e.g., by toxin production) or indirect damage (e.g., due to disorders in fat metabolism or hypoxia) may lead to osteonecrosis. Patients at increased risk for osteonecrosis should be monitored closely. Unfortunately, most cases are diagnosed in an advanced stage of disease, when minimally invasive surgical procedures are no longer helpful. Furthermore, patients in the advanced stage of the disease must undergo total hip replacement at a young age, which carries a poor long-term prognosis.

Ischial spine projection into the pelvis : a new sign for acetabular retroversion.

AbstractFemoroacetabular impingement may occur in patients with so-called acetabular retroversion, which is seen as the crossover sign on standard radiographs. We noticed when a crossover sign was present the ischial spine commonly projected into the pelvic cavity on an anteroposterior pelvic radiograph. To confirm this finding, we reviewed the anteroposterior pelvic radiographs of 1010 patients. Nonstandardized radiographs were excluded, leaving 149 radiographs (298 hips) for analysis. The crossover sign and the prominence of the ischial spine into the pelvis were recorded and measured. Interobserver and intraobserver variabilities were assessed. The presence of a prominent ischial spine projecting into the pelvis as diagnostic of acetabular retroversion had a sensitivity of 91% (95% confidence interval, 0.85%–0.95%), a specificity of 98% (0.94%–1.00%), a positive predictive value of 98% (0.94%–1.00%), and a negative predictive value of 92% (0.87%–0.96%). Greater prominence of the ischial spine was associated with a longer acetabular roof to crossover sign distance. The high correlation between the prominence of the ischial spine and the crossover sign shows retroversion is not just a periacetabular phenomenon. The affected inferior hemipelvis is retroverted entirely. Retroversion is not caused by a hypoplastic posterior wall or a prominence of the anterior wall only and this finding may influence management of acetabular disorders. Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Low Risk of Thromboembolic Complications With Tranexamic Acid After Primary Total Hip and Knee Arthroplasty

BackgroundThe use of antifibrinolytic medications in hip and knee arthroplasty reduces intraoperative blood loss and decreases transfusion rates postoperatively. Tranexamic acid (TXA) specifically has not been associated with increased thromboembolic (TE) complications, but concerns remain about the risk of symptomatic TE events, particularly when less aggressive chemical prophylaxis methods such as aspirin alone are chosen.Questions/purposesWe determined whether the rate of symptomatic TE events differed among patients given intraoperative TXA when three different postoperative prophylactic regimens were used after primary THA and TKA.MethodsWe retrospectively reviewed 2046 patients who underwent primary THA or TKA and received TXA from 2007 to 2009. The three chemical regimens included aspirin alone, warfarin (target international normalized ratio, 1.8–2.2), and dalteparin. Primary outcome measures were venous TE events, including symptomatic deep vein thrombosis (DVT) and pulmonary embolism (PE), and arterioocclusive events, including myocardial infarction and cerebrovascular accident. Patients judged to be at high risk for TE due to recent cardiac stent placement or strong personal/family history of TE disease were excluded.ResultsFor aspirin, warfarin, and dalteparin, the rates of symptomatic DVT (0.35%, 0.15%, and 0.52%, respectively) and nonfatal PE were similar (0.17%, 0.43%, and 0.26%, respectively). There were no fatal PE. Among the three groups, we found no difference in the rates of symptomatic DVT or PE with or without stratification by ASA score.ConclusionsA low complication rate was seen when using TXA as a blood conservation modality during primary THA and TKA with less aggressive thromboprophylactic regimens such as aspirin alone and dose-adjusted warfarin.Level of EvidenceLevel III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Iliopsoas impingement after total hip replacement: THE RESULTS OF NON-OPERATIVE MANAGEMENT, TENOTOMY OR ACETABULAR REVISION

We have reviewed a group of patients with iliopsoas impingement after total hip replacement with radiological evidence of a well-fixed malpositioned or oversized acetabular component. A consecutive series of 29 patients (30 hips) was assessed. All had undergone a trial of conservative management with no improvement in their symptoms. Eight patients (eight hips) preferred continued conservative management (group 1), and 22 hips had either an iliopsoas tenotomy (group 2) or revision of the acetabular component and debridement of the tendon (group 3), based on clinical and radiological findings. Patients were followed clinically for at least two years, and 19 of the 22 patients (86.4%) who had surgery were contacted by phone at a mean of 7.8 years (5 to 9) post-operatively. Conservative management failed in all eight hips. At the final follow-up, operative treatment resulted in relief of pain in 18 of 22 hips (81.8%), with one hip in group 2 and three in group 3 with continuing symptoms. The Harris Hip Score was significantly better in the combined groups 2 and 3 than in group 1. There was a significant rate of complications in group 3. This group initially had better functional scores, but at final follow-up these were no different from those in group 2. Tenotomy of the iliopsoas and revision of the acetabular component are both successful surgical options. Iliopsoas tenotomy provided the same functional results as revision of the acetabular component and avoided the risks of the latter procedure.

Multicenter study of complications following surgical dislocation of the hip

BACKGROUND Surgical hip dislocation enables complete exposure of the hip joint for treatment of various hip disorders.There is limited information regarding the complications associated with this procedure. Our purpose is to report the incidence of complications associated with surgical dislocation of the hip in a large, multicenter patient cohort. METHODS A retrospective, multicenter analysis of patients who had undergone surgical hip dislocation was performed.Patients who had undergone a simultaneous osteotomy were excluded. Complications were recorded, with specific assessment for osteonecrosis, trochanteric nonunion, femoral neck fracture, nerve injury, heterotopic ossification, and thromboembolic disease. We graded complications with a validated classification scheme that includes five grades based on the treatment required to manage the complication and any long-term morbidity. With this classification, a Grade-I complication is one that requires no change in the routine postoperative course, Grade II requires a change in outpatient management, Grade III requires invasive surgical or radiologic management, Grade IV is associated with long-term morbidity or is life-threatening,and Grade V results in death. RESULTS The study included 334 hips in 302 patients seen at eight different North American centers. There were eighteen complications (5.4%) that were classified as Grade I (not clinically relevant and required no deviation from routine postoperative care). There were six complications (1.8%) classified as Grade II (treated on an outpatient basis or with close observation and resolved). There were nine complications (2.7%) classified as Grade III (treatable and resolved with surgery or inpatient management). There was one complication (0.3%) classified as Grade IV (resulting in a long-term deficit). A total of thirty hips had one or more complications, for an overall incidence of 9%. Excluding heterotopic ossification, the complication rate was sixteen (4.8%) of 334. CONCLUSIONS Surgical hip dislocation is a safe procedure with a low complication rate. Many of the complications were clinically unimportant heterotopic ossification. There were no cases of femoral head osteonecrosis or femoral neck fracture, and, with the exception of one sciatic neurapraxia that partially resolved, no other complication resulted in long-term morbidity.

Descriptive Epidemiology of Femoroacetabular Impingement: A North American Cohort of Patients Undergoing Surgery

Background: Symptomatic femoroacetabular impingement (FAI) is associated with hip pain, functional limitations, and secondary osteoarthritis. There is limited information from large patient cohorts defining the specific population affected by FAI. Establishing a large cohort will facilitate the identification of “at-risk” patients and will provide a population for ongoing clinical research initiatives. The authors have therefore established a multicenter, prospective, longitudinal cohort of patients undergoing surgery for symptomatic FAI. Purpose: To report the clinical epidemiology, disease characteristics, and contemporary surgical treatment trends in North America for patients with symptomatic FAI. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Upon approval of the institutional review boards at 8 institutions, 12 surgeons enrolled consecutive patients undergoing surgical intervention for symptomatic FAI. Patient demographics, physical examination data, radiographic data, diagnoses, operative data, and standardized patient-reported outcome measures were collected. The first 1130 cases are summarized in this study. Results: A total of 1076 consecutive patients (1130 hips) were enrolled; 55% (n = 622) were female, and 45% (n = 508) were male, with an average age of 28.4 years and average body mass index (BMI) of 25.1. Demographics revealed that 88% of patients who were predominantly treated for FAI were white, 19% reported a family history of hip surgery, 47.6% of hips had a diagnosis of cam FAI, 44.5% had combined cam/pincer FAI, and 7.9% had pincer FAI. Preoperative clinical scores (pain, function, activity level, and overall health) indicated a major dysfunction related to the hip. Surgical interventions were arthroscopic surgery (50.4%), surgical dislocation (34.4%), reverse periacetabular osteotomy (9.4%), limited open osteochondroplasty with arthroscopic surgery (5.8%), and limited open by itself (1.5%). More than 90% of the hips were noted to have labral and articular cartilage abnormalities at surgery; femoral head-neck osteochondroplasty was performed in 91.6% of the surgical procedures, acetabular rim osteoplasty in 36.7%, labral repair in 47.8%, labral debridement in 16.3%, and acetabular chondroplasty in 40.1%. Conclusion: This multicenter, prospective, longitudinal cohort is one of the largest FAI cohorts to date. In this cohort, FAI occurred predominantly in young, white patients with a normal BMI, and there were more female than male patients. The disease pattern of cam FAI was most common. Contemporary treatment was predominantly arthroscopic followed by surgical hip dislocation.

Above-the-knee amputation after a total knee replacement: prevalence, etiology, and functional outcome.

Background: Despite modern surgical techniques, salvage of a failed total knee replacement remains a challenge. In certain situations, when other treatment options have been exhausted, patients with a failed total knee replacement may become candidates for above-the-knee amputation. The objective of this study was to assess the prevalence, etiology, and functional outcome of above-the-knee amputation performed proximal to an ipsilateral total knee replacement.Methods: From 1970 to 2000, 18,443 primary total knee replacements were performed at our institution; sixty-seven (0.36%) were eventually followed by above-the-knee amputation. Forty-two of the amputations were performed for a cause unrelated to the total knee replacement, most commonly peripheral vascular disease (twenty-four knees). The remaining twenty-five above-the-knee amputations were performed for causes related to the total knee replacement: nineteen were done for uncontrollable infection; two, for periprosthetic fracture; two, for pain; one, for severe bone loss; and one, for a vascular complication.Results: The twenty-five above-the-knee amputations performed for causes related to the total knee replacement were done at an average of 8.6 years (range, eight days to 23.6 years) after the replacement. The prevalence of above-the-knee amputations done for causes related to total knee replacement was 0.14%. Complications after the above-the-knee amputation included deep infection in five patients and superficial infection and skin necrosis in one each; there was also one perioperative death. Nine of the twenty-five limbs were fitted with an above-the-knee prosthesis, but only five patients were walking even to a limited degree with the prosthesis at the time of the last follow-up.Conclusions: The overall prevalence of amputation after total knee arthroplasty at our tertiary care center was 0.36%. The majority (63%) of the amputations were performed for reasons not attributable to complications of the arthroplasty. The functional outcome after amputation performed above a total knee replacement is poor. A substantial percentage of the patients were never fitted with a prosthesis, and those who were seldom obtained functional independence.Level of Evidence: Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

Failure of metal-on-metal total hip arthroplasty mimicking hip infection. A report of two cases.

New-generation metal-on-metal bearings made from cobalt-chromium alloys for use in total hip arthroplasty are now being utilized worldwide. A hypersensitivity reaction to a metal-on-metal bearing is a rare but reported complication and is thought to be a novel mode of failure of these implants1,2. These reactions were initially observed in patients with first-generation bearings and are now being reported in association with the second-generation metal-on-metal bearings currently in use3-5. Characteristic histological changes in the periprosthetic tissues obtained during revision surgical procedures in these patients have suggested the development of an immunological response2,6. Reports have suggested that the possibility of such a reaction should be considered when a patient presents with persistent, or the early reappearance of, preoperative pain symptoms, including a marked joint effusion, and the development of early osteolysis or radiolucent lines in the absence of infection2,7. Fever and elevated serum levels of inflammatory markers have routinely been reported to not occur in these patients. We describe two patients with failure of metal-on-metal implants who presented with signs that mimicked a deep-seated hip infection. To our knowledge, this has not been reported previously. Although the two cases were similar in terms of the clinical presentation, each ultimately represented a different pathological condition and etiology. The patients were informed that data concerning the case would be submitted for publication, and they consented. Case 1. A fifty-three-year-old man presented to our emergency department because of bilateral hip pain and episodes of low-grade fever three years after a bilateral metal-on-metal total hip arthroplasty. A Pinnacle acetabular component with a cobalt-chromium metal bearing surface (DePuy Orthopaedics, Warsaw, Indiana) had been implanted bilaterally. The pain had been present since the surgery, and the patient had never stopped …

Nontraumatic Osteonecrosis of the Femoral Head: Where Do We Stand Today? A Ten-Year Update.

➤ Although multiple theories have been proposed, no one pathophysiologic mechanism has been identified as the etiology for the development of osteonecrosis of the femoral head. However, the basic mechanism involves impaired circulation to a specific area that ultimately becomes necrotic.➤ A variety of nonoperative treatment regimens have been evaluated for the treatment of precollapse disease, with varying success. Prospective, multicenter, randomized trials are needed to evaluate the efficacy of these regimens in altering the natural history of the disease.➤ Joint-preserving procedures are indicated in the treatment of precollapse disease, with several studies showing successful outcomes at mid-term and long-term follow-up.➤ Studies of total joint arthroplasty, once femoral head collapse is present, have described excellent outcomes at greater than ten years of follow-up, which is a major advance and has led to a paradigm shift in treating these patients.➤ The results of hemiresurfacing and total resurfacing arthroplasty have been suboptimal, and these procedures have restricted indications in patients with osteonecrosis of the femoral head.