Clinical Orthopaedics and Related Research ®

A Publication of The Association of Bone and Joint Surgeons ®

Published in
Clinical Orthopaedics and Related Research®
Volume 466 | Issue 4 | Apr, 2008
Articles

Neonatal Incidence of Hip Dysplasia

Eli Peled MD, Mark Eidelman MD, Alexander Katzman MD, Viktor Bialik MD The advantages of sonographic examination are well known, but its main disadvantage is that it might lead to overdiagnosis, which might cause overtreatment. Variations in the incidence of developmental dysplasia of the hip are well known. We ascertained the incidence of neonatal sonographic developmental dysplasia of the hip without considering the development of those joints during followup. All 45,497 neonates (90,994 hips) born in our institute between January 1992 and December 2001 were examined clinically and sonographically during the first 48 hours of life. Sonography was performed according to Graf’s method, which considers mild hip sonographic abnormalities as Type IIa. We evaluated the different severity type incidence pattern and its influence on the total incidence during and between the investigated years. According to our study, sonographic Type IIa has major effects on the incidence of overall developmental dysplasia of the hip with a correlation coefficient of 0.95, whereas more severe sonographic abnormalities show relatively stable incidence patterns.,[object Object]

The Limbus and the Neolimbus in Developmental Dysplasia of the Hip

Joshua Landa MD, Michael Benke MD, David S. Feldman MD The limbus and the neolimbus are both pathological lesions that form in response to a developmentally dislocated hip. An understanding of these structures is integral to treatment of developmental dysplasia of the hip (DDH). Yet, we believe the current peer-reviewed orthopaedic literature and orthopaedic textbooks commonly fail to correctly use or define these terms. The neolimbus is best defined as a hypertrophied ridge of fibrocartilage in the superolateral region of the acetabulum caused by pressure from the dislocated hip on this region. The limbus is the labrum that is hypertrophied with fibrous and fibrocartilaginous overgrowth, and is a potential block to concentric reduction of a dysplastic hip. We review the early and current literature in an attempt to clarify the use of the terms limbus and neolimbus and provide an overview of the importance and treatment of these abnormal structures associated with DDH.,[object Object]

Femoral Morphology Differs Between Deficient and Excessive Acetabular Coverage

S. D. Steppacher MD, M. Tannast MD, S. Werlen MD, K. A. Siebenrock MD Structural deformities of the femoral head occurring during skeletal development (eg, Legg-Calvé-Perthes disease) are associated with individual shapes of the acetabulum but it is unclear whether differences in acetabular shape are associated with differences in proximal femoral shape. We questioned whether the amount of acetabular coverage influences femoral morphology. We retrospectively compared the proximal femoral anatomy of 50 selected patients (50 hips) with developmental dysplasia of the hip (lateral center-edge angle [LCE] ≤ 25°; acetabular index ≥ 14°) with 45 selected patients (50 hips) with a deep acetabulum (LCE ≥ 39°). Using MRI arthrography we measured head sphericity, epiphyseal shape, epiphyseal extension, and femoral head-neck offset. A deep acetabulum was associated with a more spherical head shape, increased epiphyseal height with a pronounced extension of the epiphysis towards the femoral neck, and an increased offset. In contrast, dysplastic hips showed an elliptical femoral head, decreased epiphyseal height with a less pronounced extension of the epiphysis, and decreased head-neck offset. Hips with different acetabular coverage are associated with different proximal femoral anatomy. A nonspherical head in dysplastic hips could lead to joint incongruity after an acetabular reorientation procedure.,[object Object]

Imaging in the Surgical Management of Developmental Dislocation of the Hip

Leslie Grissom MD, H. T. Harcke MD, Mihir Thacker MD Although the use of ultrasound in the diagnosis and early treatment of developmental dysplasia of the hip (DDH) has reduced the number of patients diagnosed late and decreased the number of operative procedures, surgical treatment is still needed in some patients. Late cases continue to occur as a result of missing the screening examination, being normal at initial screening and missing followup. Dysplasia may persist despite appropriate nonoperative or operative treatment. Many of these patients subsequently undergo closed or open reduction and femoral or acetabular reconstruction. Ultrasound of the hips is generally used up to 6 or 8 months of age, during which time the hips are largely cartilaginous, and radiographs after that time when bony development is more complete. Options to supplement ultrasound and radiography include arthrography, computed tomography, and magnetic resonance imaging. Several advances have been made in the imaging of DDH and its complications including acetabular labral pathology and of femoroacetabular impingement (FAI). We review imaging techniques other than ultrasound used in the management of DDH.,[object Object]

Diagnosis of Developmental Dislocation of the Hip by Sonospectrography

M. I. Safa Kapicioglu MD, Feza Korkusuz MD Because not all infants can be screened for DDH by experts, early diagnosis of developmental dysplasia of the hip (DDH) by primary health care professionals is important. We developed a broadband electroacoustic sound transmission-detection (sonospectrography) system and explored its utility in 22 patients (average age, 5.9 years; range, 0.3–14 years) with unilateral DDH in this preliminary study. Distinct from ultrasonography, the sonospectrography system functions by sound transmission and recording through tissues to differentiate between normal and abnormal hips. All hips were examined at four different hip and knee positions. The normal hip served as the control. The sonospectrography system was able to detect unilateral DDH. Dysplastic hips had lower sound transmission values when compared to normal hips in all patients and all four positions; however, the highest (X = 88.8 ± 30.2 Hz) and lowest (X = 8.3 ± 5.4 Hz) sound transmission mean values were obtained at different positions in the normal hips and those with DDH. Sound transmission values of dysplastic hips were always lower than that of normal hips when the hip and knee was flexed during measurements. Sound transmission values decreased with age. The sonospectrography system may offer a new noninvasive method in the diagnosis of unilateral DDH but requires further study of sensitivity and specificity of detecting dysplastic hips without subluxation in newborn infants.,[object Object]

Comparison of Pelvic Radiographs in Weightbearing and Supine Positions

Susanne Fuchs-Winkelmann MD, Christian-Dominik Peterlein MD, Carsten O. Tibesku MD, Stuart L. Weinstein MD We asked whether radiographic angles and signs of hip osteoarthrosis differ between radiographs of the pelvis taken in standing and supine positions. We retrospectively reviewed the radiographs of 61 patients (72 hips) with developmental dislocation of the hip. The minimum followup after closed reduction was 15 years (mean, 44 years; range, 15–64 years). We used pelvic radiographs in supine and standing positions taken at the same time and determined the following parameters: minimal joint space width, acetabular roof obliquity (AC angle), depth of the acetabulum (ACM angle), and center-edge angle. Osteoarthrosis was assessed according to Kellgren and Lawrence. Two independent observers measured all radiographs manually with a goniometer. AC angle, center-edge angle, and minimum joint space width differed between the radiographs taken in supine and standing positions at followup, whereas osteoarthrosis grading and the ACM angle did not. The AC angle depended on patient position and predicted development of osteoarthrosis. The minimum joint space width was influenced by the radiographic position with greater values in the supine position. ACM angle and the osteoarthrosis grade according to Kellgren and Lawrence were unaffected by the patient’s position.,[object Object]

Weightbearing Anteroposterior Pelvic Radiographs are Recommended in DDH Assessment

Anders Troelsen MD, Steffen Jacobsen MD, DMSc, Lone Rømer MD, Kjeld Søballe MD, DMSc Neutral pelvic positioning during recording of anteroposterior pelvic radiographs has been recommended for precise interpretation of acetabular deformities. Because the effect of pelvic positioning is controversial in the literature, we asked whether the weightbearing position would alter radiographic interpretations. We obtained sets of supine and weightbearing anteroposterior pelvic radiographs of 31 patients with developmental dysplasia of the hip and measured pelvic tilt, acetabular version, center edge angle, acetabular index, joint space width and femoral head translation. For both genders the pelvis extended when patients were repositioned from supine to weightbearing but extension was more pronounced in women compared with men. The number of patients with apparent acetabular retroversion was reduced from 11 supine to four when weightbearing. The center edge angle, acetabular index, joint space width and femoral head translation were similar in both views. We recommend weightbearing anteroposterior pelvic radiographs be obtained to assess DDH given the differences in pelvic flexion-extension and interpretations of acetabular version.,[object Object]

The Morphologic Variations of Low and High Hip Dislocation

George Hartofilakidis MD, Christos K. Yiannakopoulos MD, George C. Babis MD Three different types of congenital hip disease in adults have been distinguished based upon the position of the femoral head relative to the acetabulum and the underlying pathoanatomy of the joint: (1) dysplasia; (2) low dislocation; and (3) high dislocation. To facilitate classification of borderline or ambiguous cases, we studied the morphologic variations of low and high dislocation as observed on the radiographs of 101 hips with low and 74 hips with high dislocation. In low dislocation, 54 hips (53.5%) had extended coverage of the true acetabulum (Type B1) and 47 hips (46.5%) had limited coverage (Type B2). Among the cases with high dislocation, a false acetabulum with an adjacent femoral head occurred in 46 hips (62.2%) (Type C1), and the femoral head was floating within the gluteal muscles in 28 hips (37.8%) (Type C2). The kappa value for interobserver agreement between two raters who made radiographic measurements was 0.963, and for intraobserver agreement between the two evaluations of the same observer it was 0.946 and 0.971, respectively. The two types of low and high dislocation were associated with high intra- and interobserver agreement. Whether these distinctions have clinical utility requires further validation.,[object Object]

Treatment of Graf’s Ultrasound Class III and IV Hips Using Pavlik’s Method

Eli Peled MD, Viktor Bialik MD, Alexander Katzman MD, Mark Eidelman MD, Doron Norman MD When Pavlik introduced his method of treating congenital dislocation of the hip, he emphasized reducing the rate of osteonecrosis. Graf’s method of sonographic evaluation afforded earlier accurate diagnosis and subsequent treatment of developmental dysplasia of the hip. To ascertain whether treatment duration, gender, age at diagnosis, clinical stability, and/or treatment onset correlate with the risk of osteonecrosis in Graf Type III or IV hips, we clinically and sonographically screened 18,067 neonates (36,134 hips) for developmental dysplasia of the hip over a 4-year period; 151 had Graf Type III or IV hips, and 78 of these were treated by us and had known outcomes. Of these 78 hips, 65 (0.18%) had Graf Type III and 13 (0.036%) had Graf Type IV hips. Sixteen of the 65 Type III hips (25%) reduced spontaneously. Using Pavlik’s method, reduction was achieved in 46 of 65 (88.5%) Type III hips and eight of 13 Type IV hips. None of the hips treated exclusively by Pavlik’s method developed osteonecrosis. Thus, the method achieves one of Pavlik’s original goals of decreasing osteonecrosis incidence to close to zero.,[object Object]

Outcome in Unilateral or Bilateral DDH Treated with One-stage Combined Procedure

Mehmet Subasi MD, Huseyin Arslan MD, Oguz Cebesoy MD, Orhan Buyukbebeci MD, Ahmet Kapukaya MD The surgical treatment of patients with neglected developmental dysplasia of the hip (DDH) has been the subject of controversy. We asked if age affected outcome in patients with neglected DDH with unilateral or bilateral dislocation who underwent one-stage combined procedures. We retrospectively reviewed the results of 40 patients (51 hips) treated with a one-stage combined procedure consisting of open reduction, pelvic osteotomy, and femoral shortening. The average age at the time of surgery was 5.4 years for Group I (bilateral dislocation, 22 hips) and 6.7 years for Group II (unilateral dislocation, 29 hips). Mean followup was 5.4 years for Group I and 6.7 years for Group II. According to the modified score system of Trevor et al, 13 hips rated excellent, three were good, and six were fair in Group I; the ratings were 14, nine, and six hips respectively in Group II. Four patients had a limb-length discrepancy of approximately 1.5 cm in Group I. Twelve hips in Group I and 18 hips in Group II had osteonecrosis of varying severity. Our data suggest the outcomes of the children who were 5.5 years or younger in Group I and 8 years or younger in Group II were better.,[object Object]

How Are Outcomes Affected by Combining the Pemberton and Salter Osteotomies?

Aysegul Bursalı MD, Murat Tonbul MD The Pembersal operation combines features of the Pemberton and Salter osteotomies. Results have usually been reported in patients with dysplasia but without frank dislocation. We asked if the following factors influence the outcome of the Pembersal operation in patients with dislocated hips: triradiate cartilage damage causing early closure; the acetabular index improvement; and the age of the patient at time of operation. We assessed triradiate cartilage damage, a modified McKay clinical classification, acetabular index, center-edge angles, Reimers index, acetabular depth-to-width ratios, Severin classification and Tönnis grading of 33 patients (44 hips) have been evaluated in this retrospective study. The mean age at surgery was 5 years (range, 1.5–14 years). The minimum followup was 5 years (mean, 10.5 years; range, 5–17 years). Preoperatively, three (7%) hips were Tönnis Grade 2, 10 (23%) were Grade 3, and 31 (70%) were Grade 4. Eight (18%) hips were Severin Class 1, 32 (73%) Class 2, and four (9%) were Class 3. According to McKay’s criteria satisfactory results with a rate of 76% were obtained. Premature closure of the triradiate cartilage occurred in eight (18%) hips and postoperative avascular necrosis of the femoral head in three (6%) hips. Satisfactory clinical and radiographic improvements in the aforementioned parameters can be obtained by Pembersal osteotomy.,[object Object]

Posteromedial Limited Surgery in Developmental Dysplasia of the Hip

Ali Biçimoğlu MD, Haluk Ağuş MD, Hakan Ömeroğlu MD, Yücel Tümer MD We questioned whether our modified soft tissue surgical procedure can provide acceptable results with lower complication rates in developmental dysplasia of the hip (DDH). We retrospectively reviewed 143 patients (185 hips) with a mean age of 11.6 months at operation and a minimum followup of 5 years (mean, 7.5 years; range, 5–13 years). We used a posteromedial approach and sectioned the adductor longus and iliopsoas tendons. If we achieved an arthrographically documented anatomic reduction we closed the incisions; if not, we made an arthrotomy to obtain an anatomic reduction through the same incision at the same session. A hip score indicating an acceptable outcome was obtained in 168 hips (90.8%). We identified osteonecrosis of the femoral head (ON) in 36 (19.5%) hips and redislocation in four (2.2%). Both the ossific nucleus and physis were affected in 10 of the 36 hips with ON. We performed secondary operations in 12 hips (6.5%). Hips of the infants after walking age and hips with higher preoperative dislocation grades, acetabular indices, and ON were more prone to having lower hip scores. Based on the data, we believe routine arthrotomy is not needed during posteromedial surgery in DDH and this modified procedure was safe and effective.,[object Object]

No Detectable Major Changes in Gait Analysis After Soft Tissue Release in DDH

Hakan Ömeroğlu MD, Güneş Yavuzer MD, PhD, Ali Biçimoğlu MD, Haluk Ağuş MD, Yücel Tümer MD The iliopsoas and adductor tendons are often soft tissue barriers obstructing relocation of the femoral head into the acetabulum and are frequently released to obtain reduction. We assessed whether posteromedial soft tissue release including sectioning of the adductor longus and iliopsoas tendons would lead to alterations in joint angles and moments of the hip joint or other major changes in the gait pattern. We conducted 3-D quantitative gait analysis of 10 patients (mean age, 8.1 years) who had unilateral and surgically treated DDH before the age of 18 months. The mean single support time was shorter in the unaffected side of the patients than in the healthy control group. Mean pelvic excursions in both frontal and sagittal planes and maximum knee extension at stance of the affected and unaffected sides were higher in the patients than in the control group. Peak hip flexion moment during swing phase was somewhat reduced, and the hip moment crossover point from extension to flexion was slightly delayed in both the affected and unaffected sides. We could not identify an explanation for the slight deviations due to limited data. However, sectioning of the adductor longus and iliopsoas tendons in DDH patients under 18 months old did not appear to lead to major objective clinical gait alterations.,[object Object]

Endoscopy-assisted Periacetabular Osteotomy

Muharrem Inan MD, Alper Gokce MD, Fulya Ustunkan BS Periacetabular osteotomy has been recommended for reconstructing symptomatic dysplastic hips in adolescents and young adults, but requires substantial incisions and exposure. To minimize large incisions, we asked whether periacetabular osteotomy could be performed with a mini-incision under direct endoscopic control. We used five fresh-frozen cadaver pelves and developed curved guides and osteotomes for the osteotomy. We were able to perform a periacetabular osteotomy under endoscopic and image intensifier control and to fix the osteotomy with two cannulated screws. We identified no damage to vital structures or intraarticular fracture in any of the five cadavers we subsequently dissected. We believe periacetabular osteotomy may be performed with a mini-incision under direct endoscopic control. Our preliminary observations suggest the approach might be explored in limited prospective clinical trials by experienced individuals.

Developmental Dysplasia of the Hip and Occult Neurologic Disorders

A. Z. Luther, N. M. P. Clarke MB ChB, ChM FRCS Developmental dysplasia of the hip (DDH) is a neonatal condition with various causes. Neuromuscular dysplasia of the hip (NDH) is a sequel of neuromuscular disease, and generally presents later in childhood than DDH. Some evidence, however, supports a concept of a neuromuscular etiology of DDH: (1) a high prevalence of spinal dysraphism in DDH; and (2) abnormal sensory evoked potentials in 31% of DDH patients. To explore this suggestion we ascertained the presence of neuromuscular disease within a cohort of DDH patients, and asked whether the neuromuscular condition is the initial etiology of the dysplasia or a coincidental finding. We retrospectively reviewed patients presenting with DDH. Only those with an initial diagnosis of DDH and a subsequent diagnosis of a neuromuscular condition were assessed. Fifteen of 560 patients fulfilled the criteria, however the presence of true DDH within this group was minimal, as several cases emerged as early presenting NDH. We therefore believe it unlikely DDH has a substantial neurological etiology.,[object Object]

Exclusion of COL2A1 and VDR as Developmental Dysplasia of the Hip Genes

Michele Rubini PhD, Alessandra Cavallaro PhD, Elisa Calzolari MD, Giulia Bighetti MD, Vincenzo Sollazzo MD Developmental dysplasia of the hip (DDH) is a spectrum of disorders affecting the proximal femur and/or acetabulum leading to an abnormal formation of the hip. Genetic factors are involved in the etiology of DDH. Early recognition of DDH affords the best results from treatment and a better knowledge of the genetics of DDH could enhance early diagnosis. Variants in the Type II collagen (COL2A1) and vitamin D receptor (VDR) genes have been associated with patients with osteoarthritis of the hip secondary to DDH, suggesting these genes could contribute to DDH. To see whether there was linkage between the COL2A1/VDR locus and nonsyndromic DDH, we conducted a linkage study on 11 families with multiple cases of DDH. We demonstrated no evidence of linkage between the COL2A1/VDR locus and nonsyndromic DDH (LOD score < −2), suggesting, although variants in these genes could play a role in osteoarthritis in patients with DDH, they do not contribute to nonsyndromic DDH. The search for causal gene variants should proceed with other candidates.

Cumulative Hip Contact Stress Predicts Osteoarthritis in DDH

Blaž Mavčič MD, PhD, Aleš Iglič PhD, Veronika Kralj-Iglič PhD, Richard A. Brand MD, Rok Vengust MD, PhD Hip stresses are generally believed to influence whether a hip develops osteoarthritis (OA); similarly, various osteotomies have been proposed to reduce contact stresses and the risk of OA. We asked whether elevated hip contact stress predicted osteoarthritis in initially asymptomatic human hips. We identified 58 nonoperatively treated nonsubluxated hips with developmental dysplasia (DDH) without symptoms at skeletal maturity; the control group included 48 adult hips without hip disease. The minimum followup was 20 years (mean, 29 years; range, 20–41 years). Peak contact stress was computed with the HIPSTRESS method using anteroposterior pelvic radiographs at skeletal maturity. The cumulative contact stress was determined by multiplying the peak contact stress by age at followup. We compared WOMAC scores and radiographic indices of OA. Dysplastic hips had higher mean peak contact and higher mean cumulative contact stress than normal hips. Mean WOMAC scores and percentage of asymptomatic hips in the study group (mean age 51 years) were similar to those in the control group (mean age 68 years). After adjusting for gender and age, the cumulative contact stress, Wiberg center-edge angle, body mass index, but not the peak contact stress, independently predicted the final WOMAC score in dysplastic hips but not in normal hips. Cumulative contact stress predicted early hip OA better than the Wiberg center-edge angle.,[object Object]

Glenosphere Disengagement

Bart Middernacht MD, Lieven Wilde MD, PhD, Daniel Molé MD, PhD, Luc Favard MD, PhD, Philippe Debeer MD, PhD Implant failure is a serious complication in reverse shoulder arthroplasty. We determined the incidence of glenosphere disengagement in a cohort of 479 reverse shoulder prostheses (468 Delta III™ [DePuy International Ltd, Leeds, UK], 11 Aequalis™ [Tornier, Grenoble, France]). We also determined whether disengagement adversely affected clinical outcomes. The minimum followup was 12 months (mean, 28.6 months; range, 12–72 months). Disengagement of the glenosphere occurred in 16 of 479 shoulders (3.2%). In 13 patients, the disengagement was partial (clear step-off between the baseplate and the glenosphere) and was not associated with a poor functional outcome with this short-term followup. In three patients, the disengagement led to a fracture of the central screw, leading to a complete disengagement of the glenosphere from the baseplate, necessitating revision in two; the third refused revision. Partial disengagement was seen in five of 11 Aequalis™ prostheses (45.4%) and eight of 468 Delta III™ prostheses (1.7%). The three total disengagements with central screw breakage all occurred in Delta III™ prostheses. We believe differences in the type of locking screws may explain the differences observed between the two types of reverse prostheses.,[object Object]

Oblique Closing Wedge Osteotomy and Lateral Plating for Cubitus Varus in Adults

Hyun Sik Gong MD, PhD, Moon Sang Chung MD, PhD, Joo Han Oh MD, PhD, Hoyune Esther Cho, Goo Hyun Baek MD, PhD Corrective osteotomy around the elbow can require longer recovery time in adults than in children because of the longer healing period and the propensity for stiffness. We hypothesized a lateral oblique closing wedge osteotomy with a larger contact area and fixation with a lag screw plus early motion would provide stable fixation and early motion recovery in adults with cubitus varus deformity. Twelve consecutive patients who needed surgery were treated using this procedure. They were allowed active motion exercises 1 week postoperatively. The age of the patients at the time of surgery averaged 39 years (range, 31–48 years). The minimum followup was 15 months. All patients achieved healing of the osteotomy, and regained preoperative arcs of elbow motion at a mean of 7.3 weeks (range, 2–12 weeks) postoperatively. The average humerus-elbow-wrist angle improved from −23.3° to 8° (p < 0.002) by a mean gain of 29.6°. The mean lateral prominence index did not increase postoperatively. The final MEPI and DASH score averaged 95.4 points and 5.5 points. No patient experienced nerve palsy. Oblique osteotomy and fixation with a lag screw and lateral plating is a reasonable alternative technique for cubitus varus in adults, with early recovery of elbow motion and satisfactory deformity correction.,[object Object]

Lumbar Nerve Root Occupancy in the Foramen in Achondroplasia

Hitesh N. Modi MS, Seung Woo Suh MD, PhD, Hae-Ryong Song MD, PhD, Jae Hyuk Yang MD Lumbar stenosis is common in patients with achondroplasia because of narrowing of the neural canal. However, it is unclear what causes stenosis, narrowing of the central canal or foramina. We performed a morphometric analysis of the lumbar nerve roots and intervertebral foramen in 17 patients (170 nerve roots and foramina) with achondroplasia (eight symptomatic, nine asymptomatic) and compared the data with that from 20 (200 nerve roots and foramina) asymptomatic patients without achondroplasia presenting with low back pain without neurologic symptoms. The measurements were made on left and right parasagittal MRI scans of the lumbar spine. The foramen area and root area were reduced at all levels from L1 to L5 between the patients with achondroplasia (Groups I and II) and the nonachondroplasia group (Group III). The percentage of nerve root occupancy in the foramen between Group I and Group II as compared with the patients without achondroplasia was similar or lower. This implied the lumbar nerve root size in patients with achondroplasia was smaller than that of the normal population and thus there is no effective nerve root compression. Symptoms of lumbar stenosis in achondroplasia may be arising from the central canal secondary to degenerative disc disease rather than a true foraminal stenosis.,[object Object]

Utilization of Elective Hip and Knee Arthroplasty by Age and Payer

Dan Matlock MD, Mark Earnest MD, PhD, Anne Epstein PhD Elective joint arthroplasty improves the quality of life for patients with severe arthritis. In the United States, utilization of services varies with insurance status. We asked the following questions: (1) Is there an increase in the utilization of elective hip and knee arthroplasty after age 65? (2) Does the difference in utilization between the insured and general populations decrease at age 65 (the age at which Medicare provides near universal coverage)? (3) Does Medicare become the primary payer of elective hip and knee arthroplasty after the age of 65? We used the National Inpatient Sample to identify patients and payers of elective hip and knee arthroplasties by age. We analyzed these data using regression models. At age 65, there was an upward shift in the incidence of arthroplasties in the general and the insured populations and the difference between these two populations decreased. Medicare was the primary payer for the majority of arthroplasties after age 65. We conclude at age 65 the following occurs: (1) utilization of elective joint arthroplasty increases; (2) the difference between the insured population and the general population decreases; and (3) Medicare becomes the primary payer of arthroplasties.

The Influence of Surgical Approach on Outcome in Birmingham Hip Resurfacing

Callum W. McBryde MRCS, Matthew P. Revell FRCS (Tr & Orth), Andrew M. Thomas FRCS, Ronan B. Treacy FRCS (Orth), Paul B. Pynsent PhD Various approaches have been described for metal-on-metal hip resurfacing. We compared the posterolateral and direct lateral approaches for complications, pain, function, and implant survival in the short and medium term for two surgeons in a consecutive series of 790 patients (909 hips; July 1997 to July 2004) followed until July 2007. The direct lateral approach group included 135 resurfacing procedures and the posterolateral group included 774 procedures. There was no difference between the two groups for age or gender. The minimum followup for the anterolateral group was 2 years (mean, 5.1 years; range, 2.0–9.4 years) and for the posterolateral group 2 years (mean, 5.5 years; range, 2.0–9.6 years). There were no differences between the two approaches for complications, additional surgery, implant survival, or Oxford hip scores. The 8-year survival rate was 97.9% (95% confidence interval, 89.9–100) for the direct lateral approach and 97.2% (95% confidence interval, 93.9–99.3) for the posterolateral approach. This study indicates both approaches offer excellent pain reduction and return to function after Birmingham hip resurfacing with no difference in survival or in the incidence of complications. An 8-year survival rate of 97% can be achieved using either the posterolateral approach or the direct lateral approach.,[object Object]

Trochanteric Advancement in Patients with Legg-Calvé-Perthes Disease Does Not Improve Pain or Limp

Sun Young Joo MD, Ki Seok Lee MD, Il Hyun Koh MD, Hui Wan Park MD, Hyun Woo Kim MD Premature closure of the proximal epiphysis in patients with Legg-Calvé-Perthes disease can cause overgrowth of the greater trochanter. We asked whether distal transfer of the greater trochanter relieved pain and improved limp and whether the operation changed frontal plane kinematic and kinetic parameters of the hip and pelvis in the gait analysis. We reviewed 15 patients (15 hips) with an average age of 16.9 years (range, 13–26 years) who had the operation and were followed for a minimum of 28 months (average, 42 months; range, 28–54 months). The Iowa hip score increased from 85.0 (range, 75.5–87.0) before surgery to 89.1 (range, 83.0–97.0) at the final followup. Only three patients had no pain and Trendelenburg sign postoperatively. Pelvic obliquity angle of affected and contralateral normal hips in ipsilateral stance and contralateral swing phases remained unchanged after surgery. Hip adduction angle and abductor moment during single stance phase of affected and contralateral normal hips were not changed. We concluded trochanteric advancement does little to relieve pain and improve limp in patients with relative overgrowth of the greater trochanter and Legg-Calvé-Perthes disease.,[object Object]

Computer Navigation Did Not Improve Alignment in a Lower-volume Total Knee Practice

W. P. Yau MBBS, FRCSE, FHKCOS, K. Y. Chiu FHKCOS, J. L. Zuo MD, W. M. Tang FHKCOS, T. P. Ng FHKCOS Postoperative alignment of the implanted prosthesis in computer-navigated TKA has been reported to be superior to that using the conventional technique. There is an assumption that use of computer navigation techniques can make an inexperienced or occasional TKA surgeon perform more like an expert TKA surgeon. To assess improved accuracy in recreation of mechanical alignment in TKA performed using computer navigation, a retrospective review of the experience of one of the authors (WPY) before and after using computer navigation was performed. We reviewed the radiographic results of 104 TKAs (52 computer navigation, 52 conventional technique) and found the accuracy of postoperative radiographic alignment of the implanted prosthesis was not improved by using computer navigation as judged by (1) overall limb alignment (case: varus 1.3°; control: varus 0.3°); (2) femoral component alignment (case: 90.3°; control: 90.3°); and (3) tibial component alignment (case: 89°; control: 90°). Significant factors that affected postoperative overall mechanical alignment in the current navigation series included severity of the preoperative deformity, amount of error in making bone cuts, and experience of the surgeon in using the computer navigation system.,[object Object]

Joint Gap Changes with Patellar Tendon Strain and Patellar Position During TKA

Ryuichi Gejo MD, PhD, Yuji Morita MD, Isao Matsushita MD, PhD, Kazuhito Sugimori MD, PhD, Tomoatsu Kimura MD, PhD Balancing of the joint gap in extension and flexion is a prerequisite for success of a total knee arthroplasty. The joint gap is influenced by patellar position. We therefore hypothesized the state of the knee extensor mechanism (including the patellar tendon) would influence the joint gap. In 20 knees undergoing posterior-stabilized type total knee arthroplasties, we measured the joint gap and the patellar tendon strain from 0° to 135° flexion with the femoral component in position. When the patella was reduced, the joint gap was decreased at 90° and 135° (by 1.9 mm and 5.5 mm, respectively) compared with the gap with the patella everted. The patellar tendon strain increased with knee flexion. Patellar tendon strain at 90° flexion correlated with the joint gap difference with the patella in everted and reduced positions. This suggests that in addition to the collateral ligaments, the knee extensor mechanism may have an influence on the joint gap. Therefore, accounting for extensor mechanism tightness may be important in achieving the optimal joint gap balance during total knee arthroplasty.,[object Object]

Treatment of Focal Articular Cartilage Defects in the Knee

Robert A. Magnussen MD, Warren R. Dunn MD, MPH, James L. Carey MD, Kurt P. Spindler MD We asked whether autologous chondrocyte implantation or osteochondral autograft transfer yields better clinical outcomes compared with one another or with traditional abrasive techniques for treatment of isolated articular cartilage defects and whether lesion size influences this clinical outcome. We performed a literature search and identified five randomized, controlled trials and one prospective comparative trial evaluating these treatment techniques in 421 patients. The operative procedures included autologous chondrocyte implantation, osteochondral autograft transfer, matrix-induced autologous chondrocyte implantation, and microfracture. Minimum followup was 1 year (mean, 1.7 years; range, 1–3 years). All studies documented greater than 95% followup for clinical outcome measures. No technique consistently had superior results compared with the others. Outcomes for microfracture tended to be worse in larger lesions. All studies reported improvement in clinical outcome measures in all treatment groups when compared with preoperative assessment; however, no control (nonoperative) groups were used in any of the studies. A large prospective trial investigating these techniques with the addition of a control group would be the best way to definitively address the clinical questions.,[object Object]

Haptic Feedback Can Provide an Objective Assessment of Arthroscopic Skills

George Chami MD, MRCS, MS(Orth), James W. Ward, Roger Phillips MSc, PhD, CEng, FBCS, CPIT, Kevin P. Sherman BMBCh(Oxon), FRCS, PhD The outcome of arthroscopic procedures is related to the surgeon’s skills in arthroscopy. Currently, evaluation of such skills relies on direct observation by a surgeon trainer. This type of assessment, by its nature, is subjective and time-consuming. The aim of our study was to identify whether haptic information generated from arthroscopic tools could distinguish between skilled and less skilled surgeons. A standard arthroscopic probe was fitted with a force/torque sensor. The probe was used by five surgeons with different levels of experience in knee arthroscopy performing 11 different tasks in 10 standard knee arthroscopies. The force/torque data from the hand and tool interface were recorded and synchronized with a video recording of the procedure. The torque magnitude and patterns generated were analyzed and compared. A computerized system was used to analyze the force/torque signature based on general principles for quality of performance using such measures as economy in movement, time efficiency, and consistency in performance. The results showed a considerable correlation between three haptic parameters and the surgeon’s experience, which could be used in an automated objective assessment system for arthroscopic surgery.,[object Object]

Fluoroscopic Diagnosis of Scapholunate Interosseous Ligament Injuries in Distal Radius Fractures

Bong Cheol Kwon MD, Goo Hyun Baek MD Early diagnosis of scapholunate interosseous ligament tears with distal radius fractures is likely important in treatment and outcome, but identification of these injuries has not been well explored. We asked whether there was a difference in the scapholunate interval between high-grade and low-grade tears of the scapholunate interosseous ligament in distal radius fractures, the best position of the wrists to identify any differences; we also asked what gap width accurately identified high-grade tears on fluoroscopic evaluation. We fluoroscopically evaluated the scapholunate gap in six different wrist positions and then performed arthroscopic examination in 45 distal radius fractures in 44 consecutive patients. The tears were classified as high-grade (Grade 3 or greater) or low-grade (Grade 2 or less) based on arthroscopic findings. We then compared the scapholunate gap measured on fluoroscopic images between the high-grade tear group and the low-grade tear group and between the different positions of the same wrist. The scapholunate gap was wider in the high-grade tear group than in the low-grade tear group and wider in ulnar deviation than in radial deviation. A 2-mm scapholunate gap appeared the best cutoff point for the fluoroscopic diagnosis. We concluded fluoroscopic examination is a good test for identifying high-grade tears of the scapholunate interosseous ligament in distal radius fractures.,[object Object]

Self-assembled Monolayer Films of Phosphonates for Bonding RGD to Titanium

Andras Heijink MD, Jeffrey Schwartz PhD, Mark E. Zobitz MS, K. Nicole Crowder MS, Gregory E. Lutz MD, Jean D. Sibonga PhD Modification of the implant surface with the Arg-Gly-Asp tripeptide (RGD) putatively facilitates osteoblast attachment for improved implant fixation in the laboratory. We compared the histomorphometric and mechanical performance of titanium implants coated with RGD using a novel interface of self-assembled monolayers of phosphonates (RGD/SAMP) and implants coated with RGD using the more conventional thiolate-gold interface (RGD/thiolate-gold). We hypothesized RGD/SAMP-coated implants would show greater bone ongrowth and implant fixation than RGD/thiolate-gold-coated ones. We implanted an RGD/SAMP-coated implant in one femur and an RGD/thiolate-gold-coated in the contralateral femur of 60 rats. At 2, 4, and 8 weeks after implantation, 10 rats were sacrificed for histologic evaluation and another 10 for biomechanical testing. Bone-implant ongrowth and implant force-to-failure of the two implants were similar at all times. Although RGD/SAMP-coated implants did not show superior bone ongrowth and implant fixation, RGD/SAMP-coated implants have at least equally good histomorphometric and mechanical in vivo performance as RGD/thiolate-gold-coated ones. Additional in vivo characterization of self-assembled monolayer films of phosphonates as interface to bond RGD to titanium is needed to explore its full potential and seems justified based on the results of this study.

Management of Confounding in Controlled Orthopaedic Trials

Patrick Vavken MD, Georg Culen MD, Ronald Dorotka MD Confounding occurs when the effect of an exposure on an outcome is distorted by a confounding factor and will lead to spurious effect estimates in clinical studies. Although confounding can be minimized at the design stage, residual confounding may remain. An argument therefore can be made for controlling for confounding during data analysis in all studies. We asked whether confounding is considered in controlled trials in orthopaedic research and hypothesized the likelihood of doing so is affected by participation of a scientifically trained individual and associated with the magnitude of the impact factor. We performed a cross-sectional study of all controlled trials published in 2006 in eight orthopaedic journals with a high impact factor. In 126 controlled studies, 20 (15.9%; 95% confidence interval, 9.5%–22.3%) studies discussed confounding without adjusting in the analysis. Thirty-eight (30.2%; 95% confidence interval, 22.2%–38.2%) controlled for confounding, although we suspect the true proportion might be somewhat higher. Participation of a methodologically trained researcher was associated with (odds ratio, 3.85) controlling for confounding, although there was no association between impact factor and controlling for confounding. The question remains to what extent the validity of published findings is affected by failure to control for confounding.

Case Report

Florian Barvencik MD, Matthias Gebauer MD, Thorsten Schinke PhD, Michael Amling MD [object Object]

Case Report

Benjamin E. Tuy MD, Abimbola A. Obafemi BS, Kathleen S. Beebe MD, Francis R. Patterson MD Human chorionic gonadotropin is a glycoprotein hormone normally synthesized by placental syncytiotrophoblast cells. It also is secreted by gestational trophoblastic tumors, gonadal tumors, and even various nongonadal tumors, including bone and soft tissue sarcomas, as a paraneoplastic syndrome. The literature contains one case report of beta human chorionic gonadotropin production from a primary bone sarcoma occurring in a male patient. We report a woman of childbearing age who presented with a distal femur lytic lesion, clinical symptoms suggestive of pregnancy, and elevated serum beta human chorionic gonadotropin. Although the clinical diagnosis of a sarcoma was never in doubt, we present this case to emphasize a need to exclude pregnancy in women of childbearing age to avoid delay in biopsy and subsequent management. Positive immunohistochemical staining of the biopsy specimen established the tumor cells as the source of beta human chorionic gonadotropin.

A 36-year-old Woman With Posterior Shoulder Pain

Kevin M. MacDonald MD, Stephanie Koplin MD, James Choi MD, John P. Heiner MD
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