Michael B. Millis

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.

Debridement of the Adult Hip for Femoroacetabular Impingement: Indications and Preliminary Clinical Results

Untreated femoro-acetabular impingement is a common cause of osteoarthrosis of the hip. Surgical debridement of the adult hip with femoro-acetabular impingement recently has been advocated with the aim of relieving symptoms and slowing or halting progression of the arthrosis. At surgery, femoral sources of impingement are relieved by debriding the aspheric peripheral portion of the femoral head and the adjacent femoral neck. Acetabular sources of impingement can be relieved by debridement of the anterior rim. The most fundamental questions concerning these procedures relate to the preoperative and postoperative function, postoperative survivorship of these hips and the incidence of osteonecrosis. The current study assesses a group of 23 hips in 23 patients treated by surgical debridement for impingement. Twenty-two patients were treated by full surgical dislocation and one patient was treated by relief of impingement without dislocation. Followup ranged from a minimum of 2 years to 12 years. At most recent evaluation, seven patients had been converted to total hip arthroplasty, one had arthroscopic debridement of a recurrent labral tear, and 15 patients have had no further surgery. No hips developed osteonecrosis. Of the seven patients who had to have their procedure converted to total hip arthroplasty, three of these hips failed early and four patients’ hips recovered and functioned well and subsequently deteriorated with total hip arthroplasty done between 6.4 and 9.5 years after debridement. Hips at greatest risk of failure have advanced arthrosis or a combination of impingement and instability preoperatively. The procedure effectively treats hips with impingement and without considerable secondary arthrosis or instability.

Assessment of Early Osteoarthritis in Hip Dysplasia with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage

BACKGROUND The efficacy of surgical and medical treatment of osteoarthritis is difficult to assess because of the lack of a noninvasive, sensitive measure of cartilage integrity. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) was designed to specifically examine glycosaminoglycan changes in articular cartilage that occur during the development of osteoarthritis. Our primary goal was to compare this technique with measurement of the joint space width on conventional radiographs in patients with hip dysplasia. We performed this comparison by assessing the correlation between the findings of each technique and clinically important factors such as pain, severity of dysplasia, and age. METHODS Sixty-eight hips in forty-three patients were included in the study. Clinical symptoms were assessed with use of the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) questionnaire. The width of the joint space as well as the lateral center-edge angle of Wiberg (as a measure of the severity of the dysplasia) was measured on standard standing radiographs. Magnetic resonance imaging maps of glycosaminoglycan distribution were made with T1-calculated images after administration of gadopentetate (2-) (Gd-DTPA (2-) ). The dGEMRIC index was calculated as the average of the T1 values for the acetabular and femoral head cartilages. RESULTS The dGEMRIC index correlated with both pain (rs = -0.50, p < 0.0001) and the lateral center-edge angle (rs = 0.52, p < 0.0001), whereas the joint space width did not correlate with either, with the numbers available. There was a correlation between the dGEMRIC index and pain whether or not a labral tear was present. The dGEMRIC index was significantly different (p < 0.0001) among three groups of hips classified according to whether they had mild, moderate, or severe dysplasia, whereas the joint space width did not differ significantly among these three groups. There was no significant correlation between age and any of the other parameters. CONCLUSIONS We demonstrated that, in patients with hip dysplasia, the dGEMRIC index-a measure of the biochemical integrity of cartilage-correlates with pain and the severity of the dysplasia and is significantly different among groups of hips with mild, moderate, and severe dysplasia, suggesting that it may be a sensitive measure of early osteoarthritis. Additional studies are needed to determine whether dGEMRIC can be used to predict disease progression in different situations and/or demonstrate responses to therapeutic interventions.

Delayed gadolinium-enhanced magnetic resonance imaging of cartilage to predict early failure of Bernese periacetabular osteotomy for hip dysplasia.

BACKGROUND Hip dysplasia leads to abnormal loading of articular cartilage, which results in osteoarthritis. Pelvic osteotomies such as the Bernese periacetabular osteotomy can improve the mechanics of the joint, but the results are variable and appear to depend on the amount of preexisting arthritis. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a technique designed to measure early arthritis, and it potentially could be used to select hips with too severe arthritis to benefit from a joint-preserving reconstructive procedure. The purpose of our study was to identify radiographic, clinical, and magnetic resonance imaging measurements that predict failure after pelvic osteotomy. METHODS We performed a cohort study of forty-seven patients undergoing a Bernese periacetabular osteotomy for the treatment of hip dysplasia. Our goal was to identify preoperative radiographic factors, such as the grade of arthritis, joint congruency, and the dGEMRIC index, that are associated with a poor outcome after osteotomy. RESULTS Hips in which the osteotomy did not fail had a significant decrease in pain compared with their status preoperatively (p < 0.0001). Hips in which the osteotomy did fail had had significantly more arthritis on preoperative radiographs (as demonstrated by the joint space width and the Tönnis grade [p = 0.01]), more subluxation (p = 0.02), and a lower dGEMRIC index (p < 0.001) than the hips in which the osteotomy did not fail. Multivariate analysis identified the dGEMRIC index as the most important predictor of failure of the osteotomy. CONCLUSIONS Bernese periacetabular osteotomy for the treatment of hip dysplasia can decrease pain and improve function in symptomatic dysplastic hips. The dGEMRIC index, as an early measure of osteoarthritis, appears to be useful for identifying poor candidates for a pelvic osteotomy. LEVEL OF EVIDENCE Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

Acetabular Dysplasia in the Adolescent and Young Adult

Hip dysplasia is a major cause of osteoarthrosis in adults. Early aggressive osteotomy has the potential of preventing the development of arthritis, but carries with it significant risks. The problem is further complicated because the surgeon has no means of quantifying the dysplastic deformity or of predicting what a particular combination of osteotomies would do to correct the deformity. This study describes methods of quantifying hip-joint geometry in three dimensions based on computed tomography and magnetic resonance studies, and of simulating pelvic osteotomy to correct the deformities. The study analyzes 49 normal hip joints and 20 dysplastic hip joints. The results show that the normal acetabulum is nearly a full hemisphere, which is anteverted 20 degrees and abducted 53 degrees. The normal lateral center-edge angle is 37 degrees. The dysplastic acetabulum is not anterolaterally maldirected, as has been assumed, but is globally dysplastic. Analysis of the individual dysplastic hip joints showed a wide variability. Some patients were deficient globally, some anterolaterally, and some posterolaterally. Methods of analyzing a patients hip joint, quantifying abnormalities, simulating surgery, and predicting results are demonstrated in a case example.

Intermediate to Long-Term Results Following the Bernese Periacetabular Osteotomy and Predictors of Clinical Outcome

BACKGROUND The Bernese periacetabular osteotomy is a commonly used non-arthroplasty option to treat developmental hip dysplasia in symptomatic younger patients. Predicting which hips will remain preserved and which hips will go on to require arthroplasty following periacetabular osteotomy is a major challenge. In the present study, we assessed the intermediate to long-term results following periacetabular osteotomy to demonstrate the clinical outcomes for patients with varying amounts of dysplasia and arthritis. From these results, a probability-of-failure analysis was conducted to predict the likelihood of hip preservation and to improve surgical decision-making. METHODS Of the 189 hips (in 157 patients) that were treated with periacetabular osteotomy by a single surgeon from May 1991 to September 1998, thirty-one had diagnoses other than developmental hip dysplasia and twenty-three were lost to follow-up. The remaining 135 hips (in 109 patients) were retrospectively reviewed at an average of nine years. Hips were evaluated with use of the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index postoperatively as well as with radiographs that were made preoperatively and at one and more than five years postoperatively. Osteotomy failure was defined as a pain score of >or=10 or the need for total hip arthroplasty. RESULTS One hundred and two hips (76%) remained preserved at an average of nine years, with an average Western Ontario and McMaster Universities pain score of 2.4 of 20. Thirty-three hips (24%) met the failure criteria: seventeen underwent arthroplasty at an average of 6.1 years after the osteotomy, and sixteen had a postoperative pain score of >or=10. Kaplan-Meier analysis with arthroplasty as the end point revealed a survival rate of 96% (95% confidence interval, 93% to 99%) at five years and 84% (95% confidence interval, 77% to 90%) at ten years. Complications occurred in twenty hips. Fifteen hips (11%) were treated with a subsequent arthroscopy because of chondral and/or labral lesions at an average of 6.8 years after the osteotomy. Two independent predictors of failure (defined as arthroplasty or a high pain score) were identified: (1) an age of more than thirty-five years and (2) poor or fair preoperative joint congruency. The probability of failure requiring arthroplasty was 14% for hips with no predictors of failure, 36% for those with one predictor (either an age of more than thirty-five years or poor or fair joint congruency), and 95% for those with both predictors. CONCLUSIONS The Bernese periacetabular osteotomy can be effective for the treatment of painful hip dysplasia, but complications may be expected in as many as 15% of cases. The ideal candidate is the patient who is less than thirty-five years of age and who has good or excellent hip joint congruency.

Osteotomies about the Hip for the Prevention and Treatment of Osteoarthrosis

Osteoarthrosis of the hip remains a common cause of disability in our society. Despite continuing technical evolution and innovation and the widespread use of total hip anthroplasty since the 1960’s, hopes for an enduring prosthetic replacement for the osteoarthrotic hip joint remain unfulfilled7. Artificial prosthetic surfaces with the mechanical properties and durability of articuhan cartilage have yet to be found. Each new generation of artificial weight-bearing surfaces and bone-implant interfaces has, in the long nun, tended to have functional limitations. The limitations of total joint anthrophasty have demonstrated to each new generation of orthopaedic surgeons how wonderful a machine the normal hip joint is6 #{176}63. These circumstances make efforts to keep the patient’s own hip joint from failing worthwhile69. While total hip replacement is the treatment of choice for many patients who have inflammatory arthritis and for patients who are not expected to outlive the implant, arthroplasty becomes a less desirable solution in younger, more active patients in whom the cause of the osteoarthrosis is mechanically correctabhe’#{176}’2’620. It is against this background of the limitations of joint replacement arthroplasty that renewed efforts have been made to understand the etiology of osteoanthroMany joints degenerate for primarily mechanical reasons rather than biological ones6563. In such mechanically compromised joints, elevation of joint contact pressure seems to be directly related to the onset of degeneration of the articular cartilage8 . It has been postulated that timely elimination of both abnormal joint-loading and excess point contact stress may prevent the onset of osteoarthrosis. Even in a joint that

Neurovascular injury and displacement in type III supracondylar humerus fractures.

Summary From July 1987 to January 1991, 59 consecutive type III supracondylar humerus fractures in children were identified at Childrens Hospital, Boston. Twenty-nine patients (49%) had evidence of neurovascular compromise. The median nerve was involved in 15 (52%) of these patients and was associated with posterolateral displacement in 87% of cases. The radial nerve was involved in eight (28%) of these patients and was associated with posteromedial displacement in every case. Injuries to the brachial artery occurred in 11 (38%) of these patients and was associated with posterolateral displacement in 64% and posteromedial displacement in 36% of cases. We conclude that posterolateral displacement in type III supracondylar humerus fractures is strongly associated with median nerve injuries. Posteromedial displacement is responsible for injuries to the radial nerve in virtually every instance. Brachial artery injuries may occur with either type of displacement. Neurovascular injury is higher than previously reported in these fractures.

Lateral entry compared with medial and lateral entry pin fixation for completely displaced supracondylar humeral fractures in children. A randomized clinical trial.

BACKGROUND Closed reduction and percutaneous pin fixation is the treatment of choice for completely displaced (type-III) extension supracondylar fractures of the humerus in children, although controversy persists regarding the optimal pin-fixation technique. The purpose of this study was to compare the efficacy of lateral entry pin fixation with that of medial and lateral entry pin fixation for the operative treatment of completely displaced extension supracondylar fractures of the humerus in children. METHODS This prospective, randomized clinical trial had sufficient power to detect a 10% difference in the rate of loss of reduction between the two groups. The techniques of lateral entry and medial and lateral entry pin fixation were standardized in terms of the pin location, the pin size, the incision and position of the elbow used for medial pin placement, and the postoperative course. The primary study end points were a major loss of reduction and iatrogenic ulnar nerve injury. Secondary study end points included radiographic measurements, clinical alignment, Flynn grade, elbow range of motion, function, and complications. RESULTS The lateral entry group (twenty-eight patients) and the medial and lateral entry group (twenty-four patients) were similar in terms of mean age, sex distribution, and preoperative displacement, comminution, and associated neurovascular status. No patient in either group had a major loss of reduction. There was no significant difference between the rates of mild loss of reduction, which occurred in six of the twenty-eight patients treated with lateral entry and one of the twenty-four treated with medial and lateral entry (p = 0.107). There were no cases of iatrogenic ulnar nerve injury in either group. There were also no significant differences (p > 0.05) between groups with respect to the Baumann angle, change in the Baumann angle, humerocapitellar angle, change in the humerocapitellar angle, Flynn grade, carrying angle, elbow flexion, elbow extension, total elbow range of motion, return to function, or complications. CONCLUSIONS With use of the specific techniques employed in this study, both lateral entry pin fixation and medial and lateral entry pin fixation are effective in the treatment of completely displaced (type-III) extension supracondylar fractures of the humerus in children. LEVEL OF EVIDENCE Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

Experiences with leflunomide in solid organ transplantation.

BACKGROUND Leflunomide (Arava), a drug widely used for treatment of rheumatoid arthritis, has a very promising background in experimental transplantation. Its activity in experimental models of chronic rejection, its synergy with calcineurin phosphatase inhibitors, and its inhibitory effects on herpes virus replication are compelling reasons to pursue its clinical evaluation in transplantation. We report the use of this drug over the past 3 years in various clinical situations. METHODS A retrospective review was performed in 53 liver and kidney transplant recipients receiving Arava. A single-dose pharmacokinetic (PK) study was first performed in stable, renal transplant recipients, and an initially targeted serum level of 100 microg/mL (300 microM) was calculated to require a loading dose of 1200-1400 mg over a 7-day period. We correlate the appearance of toxicity with serum levels of active drug and review the outcomes in patients whose clinical condition required dose reductions of conventional immune suppressive drugs. RESULTS Fifty-three patients received leflunomide from 5 days to more than 430 days, and 37 patients received the drug for more than 60 days. The primary toxicity was anemia in the renal transplant patients and elevation of liver enzymes in the liver transplant patients. At comparable oral doses, serum levels were substantially lower and anemia more common in patients with serum creatinine >3 mg/dL. In liver and renal recipients with serum creatinine <3 mg/dL, the drug was well tolerated and dose-limiting side effects occurred in less than 15% when drug serum levels were less than 80 microg/ml. Patients with serum creatinine >3 mg/dL often required serum levels of active drug reduced to <60 microg/mL. In 12 of 18 renal patients treated for 200 days or more, the dose of cyclosporine or Prograf was reduced by a mean of 38.5% and stopped in one patient. The prednisone dose was reduced by a mean of 25% in these same 13 patients. Cyclosporine or FK506 was stopped completely in four liver recipients and reduced by 65% in another patient. No evidence of acute rejection developed in any of these liver or kidney transplant patients. CONCLUSION Leflunomide seems to possess substantial immune suppressive potency in renal and liver transplant recipients and may be safely dosed for more than 300 days. The data suggest that calcineurin phosphatase inhibitors and prednisone can be safely reduced in patients with serum levels of active drug above 50 microg/mL. Because of a wide inter-patient range of active metabolite terminal half-life (>300%), monitoring of serum levels would seem to be an important part of its evaluation.