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The results of total hip arthroplasty with the use of medial and superior bone-graft augmentation in thirty-nine hips (thirty-two patients) that had protrusio acetabuli were previously reported after two to eight years (mean, 4.7 years) of follow-up. We followed the surviving patients for 10.9 to 17.4 years (mean, 12.8 years). The average Harris hip-rating was 72 points--an average drop of 17 points since the previous report. The average was 64 points for patients who had rheumatoid arthritis and 83 points for those who had another diagnosis. Radiographic evaluation demonstrated definite, probable, and possible loosening in about 20, 10, and 60 per cent of the hips, respectively. Of the six hips that had definite loosening, four (10 per cent of the total series) had progression of the protrusion (acetabular migration); operative revision was performed on two of those four hips and on two other hips, in which progression had ceased. Hips that had progressive protrusion demonstrated superior migration more often than medial migration. The rates of loosening and revision were similar to those in hips that did not have protrusio acetabuli. We concluded that augmentation of total hip arthroplasty with bone-grafting is effective in arresting the progression of protrusio acetabuli in most hips (90 per cent in our series).

We investigated the association of developmental dysplasia of the hip (DDH) and primary protrusion acetabuli (PPA) with Vitamin D receptor polymorphisms Taq I and Fok I and oestrogen receptor polymorphisms Pvu II and Xba I. 45 patients with DDH and 20 patients with PPA were included in the study. Healthy controls (n = 101) aged 18–60 years were recruited from the same geographical area. The control subjects had a normal acetabular morphology based on a recent pelvic radiograph performed for an unrelated cause. DNA was obtained from all the subjects from peripheral blood. Genotype frequencies were compared in the three groups. The relationship between the genotype and morphology of the hip joint, severity of the disease, age at onset of disease and gender were examined. The oestrogen receptor Xba I wild-type genotype (XX, compared with Xx and xx combined) was more common in the DDH group (55.8%) than controls (37.9%), though this just failed to achieve statistical significance (p = 0.053, odds ratio = 2.1, 95% CI = 0.9–4.6). In the DDH group, homozygosity for the mutant Taq I Vitamin D receptor t allele was associated with higher acetabular index (Mann-Whitney U-test, p = 0.03). Pvu II pp oestrogen receptor genotype was associated with low centre edge angle (p = 0.07). This study suggests a possible correlation between gene polymorphism in the oestrogen and vitamin D receptors and susceptibility to, and severity of DDH. The Taq I vitamin D receptor polymorphisms may be associated with abnormal acetabular morphology leading to DDH while the Xba I oestrogen receptor XX genotype may be associated with increased risk of developing DDH. No such correlations were found in the group with PPA.

This retrospective study examined the results of 29 total hip arthroplasties on patients with protrusio acetabuli, implanted with a dual-geometry shell with a mean follow-up of 48 months (range, 24-110). All surgeries were performed using a conical reamer in addition to a spherical reamer with morsellized autogenous graft packed into the medial acetabular protrusio defect. The Harris Hip Score increased from 41 to 85. There were no cases of aseptic loosening of the acetabular component by radiographic criteria. In 93% of the cases (27 hips), the bone graft appeared incorporated, and in 83% of the cases (24 hips), there were no radiolucent lines present. Using a 2-stage technique of bone preparation to insert a dual-geometry acetabular cup, excellent results were obtained in these 29 hips.

Protrusio acetabuli is an uncommon complication of total hip arthroplasty, which results in intrapelvic implant migration after erosion of medial acetabular wall. We present a case of severe prosthetic migration with the formation of haematoma and impingement on iliac vessels leading to thrombosis and subsequent pulmonary embolus. This is the first reported case of protrusio acetabuli as a cause of pulmonary embolus.

Protrusio acetabuli is known to occur in patients with Marfan syndrome, but its prevalence, its effects on hip function, and its possible association with the subsequent development of degenerative hip disease have not been studied in a large population. Nevertheless, some clinicians have recommended prophylactic hip surgery for preadolescents with Marfan syndrome and protrusio acetabuli.We performed a cross-sectional study of 173 patients (346 hips) with Marfan syndrome who were interviewed and examined for calculation of the Iowa hip score. Anteroposterior radiographs of the pelvis were made, and two radiographic indices of acetabular depth were measured: (1) the center-edge angle of Wiberg and (2) the acetabular-ilioischial distance. The presence of protrusio was defined with use of two extant definitions: (1) a center-edge angle of >50 degrees or (2) an acetabular-ilioischial distance of >/=3 mm in male patients or >/=6 mm in female patients. Linear regression analyses were performed between these radiographic indices of acetabular depth and patient age, Iowa hip scores, the magnitude of the radiographic joint space, and range of motion.The prevalence of protrusio acetabuli was 27% according to the center-edge angle criterion and 16% according to the acetabular-ilioischial distance criterion. The prevalence of protrusio increased until the age of twenty years and remained stable after the age of twenty years. Slight but significant negative correlations were detected between the two radiographic indices of acetabular depth and both the Iowa hip score and the summed range of motion (p < 0.02 for all). No significant relationship was found between the two radiographic indices and pain scores. In patients with Marfan syndrome who were more than forty years old, the Iowa hip scores for hips with protrusio were not significantly lower than those for hips without protrusio.In patients with Marfan syndrome, the prevalence of protrusio acetabuli increases during the first two decades of life and then plateaus in terms of both population-wide prevalence and radiographic severity. In this population, protrusio generally is not associated with severely problematic hip function but it is associated with slightly decreased range of motion of the hip. We concluded that prophylactic surgical intervention is not indicated for most patients with Marfan syndrome who have a radiographic diagnosis of protrusio.

The authors reviewed all patients in Shriners Hospital for Children, Honolulu, diagnosed with hyperlaxity of the joints (131 in total) for Marfan syndrome. The revised diagnostic criteria for Marfan syndrome were used for inclusion in this study. In the patients diagnosed with Marfan syndrome (n = 13), the incidence (n = 9) and indication for surgical intervention (n = 4) of protrusio acetabuli were evaluated by retrospective radiographic review, clinical findings, and family history. For the identification of protrusio acetabuli, the presence of an abnormal acetabular line position (>1 mm medial to the ilioischial line in boys, >3 mm in girls), a center-edge angle of Wiberg of 40 degrees or more, or crossing of the teardrop by the ilioischial line was used. The authors conclude that serial radiographic investigations, reinforced with a well-documented family history of symptomatic protrusio acetabuli, are needed to rule out progression of the deformity. When progression of the deformity is suggested in a skeletally immature Marfan patient, surgical intervention by closure of the triradiate cartilage is indicated, regardless of the absence of hip complaints or limitation of range of motion.

i v r i m u e m i n 83-year-old man involved in a car crash presented ith pelvic pain. On admission he was conscious and ooperating; vital signs were stable. Inspection revealed n asymmetry and deformity in the right pelvic area. here was tenderness to palpation in the suprapubic egion, and the right hip movement was painful and imited. A hemorrhagic discharge in the urethral meatus as noticed. The initial pelvic radiographs showed muliple pelvic bone fractures including right acetabular racture and protrusion of the right femoral head. The atient was evaluated by computed tomography (CT) can, which demonstrated multiple displaced fractures of he pelvic girdle and protrusio acetabuli on the right side Figure 1). There was a large amount of extraperitoneal uid in the pelvic area. Retrograde urethrography was hen performed, which demonstrated contrast extravasaion from the posterior urethra and bladder (Figure 2). rethral leakage was prominent at the base of the blader and was also extending to the groin region. The ladder had lost its original shape. Transurethrally aplied contrast agent escaped from the bladder to the elvic space in the form of irregular, stranding densities. his radiographic appearance of extravasation is consisent with extraperitoneal rupture of the bladder. Major bladder injury occurs in approximately 10% of atients sustaining blunt trauma with pelvic fracture (1). ladder injuries resulting from pelvic fracture may take ne of two forms—contusion or rupture. Contusion of

Seventeen patients (19 hips) with protrusio acetabuli resulting from a failed total hip arthroplasty, large medial bone defect, and an intact bony rim were treated with an oversized cementless acetabular component and medial morcelized allograft. An average of 55% of the revision component was not supported by host bone. At an average follow-up of 2.8 (range 2-6) years, none of the acetabular components required revision for loosening. The average cup position preoperatively was 10.5 mm medial to Kohler's line and postoperatively was 6.8 mm lateral to Kohler's line. Despite very large medial defects, reconstructions with this technique remained stable.

We evaluated 19 hips of 15 rheumatoid arthritis patients with protrusio acetabuli that had been surgically treated with total hip arthroplasty (THA) using a support ring; four hips were replaced with a TACT cup supporter, one hip with a Kerboull plate, six hips with a Ganz ring, and eight hips with a Müller ring. The average age was 60.2 years (range 48-75 years), and the average follow-up was 38 months (range 6-74 months). Two patients (three hips) died before the final follow-up, and two patients (two hips) underwent revision owing to loosening of the Ganz ring. Hip functions were rated according to the evaluation chart of hip joint functions of the Japanese Orthopaedic Association (JOA score). The mean total JOA score was 25.2 +/- 8.6 preoperatively and 55.6 +/- 8.7 postoperatively. Radiographically, 17 hips (minus the two revised hips) showed satisfactory incorporation of bone graft and no loosening of the support ring. The mean depth of protrusio acetabuli for these 17 hips was 3.5 +/- 4.1 mm before operation, 2.8 +/- 5.1 mm just after operation, and 2.3 +/- 3.9 mm at the final follow-up (no significant difference at the critical rate of 5%). Our study indicated the usefulness of THAs using a bone graft and a support ring in RA patients with protrusio acetabuli.

A new CT-based diagnostic method of protrusio acetabuli (PA) was introduced. However, prevalence of PA by this method and correlation between PA and other manifestations of Marfan syndrome (MFS) is unknown in Korean MFS patients. This study aimed to investigate the prevalence of PA diagnosed by a CT-based method in Korean patients with MFS, the association of PA with other manifestations of MFS, and the contribution of PA to MFS diagnosis. We retrospectively reviewed the records of 146 MFS patients with the presence of a causative FBN1 mutation and 146 age- and sex-matched controls from a single tertiary care center. All MFS patients underwent a complete assessment of criteria based on the revised Ghent nosology. PA was assessed quantitatively using a CT-based circle-wall distance (CWD) method. PA was diagnosed in 77.4% of patients in the MFS group and in 11.0% of the control group. CWD was significantly different between the two groups (1.50 mm vs. -0.64 mm, P

Idiopathic chondrolysis is a rare condition characterized by the ultimate loss of femoroacetabular articular cartilage seen in a child with no history of trauma, slipped capital femoral epiphysis, infection, prolonged immobilization, or any other previously described disorder. The diagnosis is often delayed secondary to the insidious onset of symptoms, progressive radiographic findings, and the absence of diagnostic laboratory test. Typical radiographic features include localized osteoporosis, subchondral erosions, femoral head changes, and reduction of the joint space. Later changes include complete loss of the joint space, subchondral cysts, trochanteric and epiphyseal physeal closure, osteophytes, and in severe cases, protrusio acetabuli, ankylosis, and osteoarthritis. Magnetic resonance imaging of the hip demonstrates cartilage loss, joint effusion, marrow edema, femoral and acetabular remodeling, significant regional muscle atrophy, and synovial enhancement. We report a case of Idiopathic chondrolysis of the hip in an 11-year-old Indian girl.

Protrusio acetabuli is a disease characterized by a deformity of the medial wall of the acetabulum with a progressive migration of the femoral head into the pelvic cavity, resulting in some mechanical disorders, pain and limited limb hip movement. It was first described by Otto in 1824 as an intrapelvic protusion of the femoral head. It is considered multifactorial, and it is suggested that there is a heredity background to this disease. It is classified as primary (75,3%) or secundary (24,7%) according to aetiology; mild, moderate and severe radiologically. This review aims to present some treatment techniques using arthroplasties which are several and little explored. As in the literature, the choice was bone graft since there is no migration of the cemented acetabulum and no necessity of a titanium cup of great diameter. A protrusão acetabular é caracterizada por deformidade da parede medial do acetábulo com migração progressiva da cabeça femoral para o interior da pelve, causando distúrbios mecânicos, dor e importante limitação funcional da articulação do quadril. Descrita inicialmente por Otto em 1824, como uma deformidade da pelve, caracterizada pela maior profundidade da cavidade cotilóide, devido a seu afundamento. Considerada multifatorial, acredita-se haver uma tendência familiar. Quanto à etiologia é classificada em primária (75,3%) ou secundária (24,7%) e, de acordo com parâmetros radiológicos em leve, moderada e grave. O objetivo desta revisão é apresentar as técnicas de tratamento com artroplastias que são múltiplas e pouco exploradas. Em nossos pacientes, como a maioria dos autores da literatura, a protrusão da parede medial do acetábulo foi tratada com enxerto ósseo, superando e evitando a migração do componente acetabular cimentado e não havendo a necessidade de uso das conchas de titânio de grande diâmetro.

A 65-year-old woman presented with a 20-year history of seropositive rheumatoid polyarthritis. Her disease had destroyed most of her major joints of the body, including both knees, hips, elbows, wrists, finger joints, spine and joints of the feet. She had undergone a successful bilateral total knee replacement surgery 7 years ago. For the past 2 years, she had been having difficulty in standing and walking with ‘noises’ …

Abstract: This is a prospective, consecutive study of 98 total hip arthroplasties implanted by 1 surgeon in 66 patients with rheumatoid arthritis. The mean follow-up time was 7.4 years (range, 2-13 years). All 98 acetabular components were uncemented titanium fiber metal-coated components fixed with multiple screws. Sixty-five hips had bulk or cancellous allograft for protrusio acetabuli. Following a prospective protocol based on patient age, 51 hips had an uncemented femoral component, and 47 hips had a cemented femoral component. Using the Harris Hip Score, 30 hips were rated as excellent; 44, good; 15, fair; and 9, poor. There were no early deep infections. One hybrid hip was removed for late metastatic infection at 7 years. Radiographic evaluation of 98 acetabular components showed 1 case of septic loosening, 2 cases of aseptic loosening (1 patient asymptomatic), and 1 case with severe wear and ischial osteolysis. None of the 47 cemented femoral components subsided, and osteolysis was seen in only 3 femora (7%). Of the 51 uncemented femoral components, subsidence occurred in 7 hips (14%), and osteolysis occurred in 15 hips (30%). Uncemented acetabular components have a high rate of success in patients with rheumatoid arthritis who have a total hip arthroplasty. There is a high rate of subsidence and osteolysis, however, with first-generation cementless femoral components.

From 1 985-1 990, a total of 277 elderly patients underwent hemiarthroplasty using a ceramic head prosthesis. Average patient age was 81.7 years. Of these, 77 patients were available for follow-up examination in 1993. A standardized score was calculated assessing activity, gait, and hip pain; the average score was 58 out of 78 possible points. Three patients had hip pain, and in 4 patients, radiographic examination revealed protrusio acetabuli. Two of 4 patients underwent revision surgery for replacement of the cup, leaving the stem in situ. Because of the small number of prosthetic-related complications, hemiarthroplasty using a ceramic head prosthesis is the recommended surgical treatment for femoral neck fractures in elderly patients. In the rare patient with protrusio acetabuli, revision surgery can be performed to replace the cup, leaving the stem in situ.

Twenty-one patients with Marfan's syndrome participated in a study to assess the incidence of and radiographic measurements significant for protrusio acetabuli. Our data show that the incidence of protrusio acetabuli in Marfan's syndrome is 31%. The most sensitive radiographic parameter to determine protrusio acetabuli is crossing of the acetabular line by the iliopectineal line. The presence of protrusio in Marfan's syndrome was not related to the bone mineral content of the hip and pelvis. Protrusio acetabuli in Marfan syndrome's also did not correlate with clinical symptoms. Based on our results, the presence of protrusio acetabuli alone is not an indication for early surgical intervention.

This study investigated the perceived risks and complications associated with total hip arthroplasty for Paget's disease. A total of 98 Charnley low-friction arthroplasties were performed on 76 patients, 27 men (37 hips) and 49 women (61 hips), whose average age was 67.4 years (range, 51-79 years). Intraoperative blood loss averaged 388 mL (range, 110-1,730 mL), and minor heterotopic ossification occurred in 24 hips (25%), with significant changes in 4 hips (4%). After average follow-up of 10.4 years (range, 5.5-20 years), 10 acetabular (10%) and 8 femoral (8%) implants had loosened aseptically, but there was no evidence of progressive protrusio acetabuli or femoral deformity after operation. Survivorship to revision was 98% at 10 years (95% confidence interval [CI], 95%-100%) and 91% at 15 years (95% CI, 80%-100%) for the acetabular component and 93% (95% CI, 87%-99%) and 89% (95% CI, 80%-99%) for the femur. The only increased risk identified was nonunion of the trochanteric osteotomy (13%).

The MC cup supporter is an acetabular reinforcement ring for the Harris-Galante (HG) cementless porous-coated socket. This supporting ring has been used with autogenous bone graft since 1991 in the management of protrusio acetabuli in patients with rheumatoid arthritis (RA). We have reviewed 15 hips in 13 patients at an average of 53.6 months (range 24–84 months) after operation. The clinical results of total hip arthroplasty (THA) in protrusio acetabuli using this ring were satisfactory. All grafts appeared to have united radiologically with no radiolucent lines between graft and acetabulum.

Marfan's syndrome is an autosomal dominant disorder of connective tissue, commonly involving the cardiovascular, ocular, and skeletal systems. Revised criteria for the clinical diagnosis of Marfan's syndrome regard skeletal involvement as a major criterion if at least four of eight typical skeletal manifestations are present, one of which is protrusio acetabuli. Using Kulman's method to determine the presence of protrusio, we analysed the pelvic X-rays of 15 patients with Marfan's syndrome and 15 controls. Protrusio was present in 47% (7/15) of Marfan patients, compared with 7% (1/15) of controls (P = 0.035). Using the revised criteria, the presence of protrusio would have affected the final diagnosis of Marfan's syndrome in only one patient out of 15. Therefore, we recommend that a pelvic X-ray is reserved for those cases in which the presence of protrusio will alter the final diagnosis. With regard to the radiological assessment of protrusio, in our opinion this can be performed simply and reliably using the position of the acetabular line alone.

A foam model of a protrusio acetabulum with cylindrical voids of varying diameters was used to test acetabular components for their ability to resist migration within the defect. A bipolar component, a hemispherical cup, and a hemispherical cup with peripheral rim augmentation were tested in defects with diameters ranging from 1 to 3 mm less than the major diameter of the component. The cup with peripheral rim augmentation demonstrated 20% to 40% greater resistance to migration than the hemispherical cup, depending on the extent of under-reaming, with the bipolar component consistently demonstrating the lowest load to failure. The results of this study confirm the less-than-satisfactory clinical results seen with bipolar reconstruction of protrusio acetabuli, and support the use of "fixed" cups in these settings.

Background: Symptomatic femoroacetabular impingement is a known prearthritic condition. Impingement morphology is poorly defined in the adolescent population. The purpose of this study was to document the prevalence of radiographic impingement morphology in adolescents with no symptomatic hip problems. Methods: Ninety anteroposterior images of the hip in forty-five consecutive adolescents with scoliosis met the inclusion criteria. Sex distribution was equal. The second cohort (ninety hips) was an age-matched group with no scoliosis. None had symptomatic hip problems. Images were analyzed for coxa profunda, protrusio acetabuli, Tonnis angle, anteroposterior alpha angle, center-edge angle, acetabular crossover, ischial spine sign, and neck-shaft angle. Results: Of the 180 hips, 92.8% demonstrated at least one parameter suggesting impingement morphology, whereas 52.2% showed at least two signs. Evidence of coxa profunda was seen in 81.7% of the hips, while a negative Tonnis angle was seen in 31.1% and a center-edge angle indicative of acetabular overcoverage was seen in 15%. An acetabular crossover sign was detected in 27.2% of the hips, while an abnormal anteroposterior alpha angle was found in 5.6% of the hips in male patients and 6.7% of the hips in female patients. Statistical analysis revealed that abnormal alpha angles (p = 0.029), crossover signs (p = 0.029), and ischial spine signs (p = 0.026) were more common in the cohort without scoliosis, and coxa profunda was more common in females (p = 0.034). Conclusions: There was a high prevalence of radiographic impingement morphology beyond the spectrum of normal in this double-cohort study of adolescents. Femoroacetabular impingement remains a dynamic problem, and we caution against relying only on the use of hard-set static radiographic parameters when evaluating femoroacetabular impingement. This study raises the important question of what morphologic characteristics should be defined as abnormal, when at least one finding of impingement morphology is noted in such a large segment of the population. On the basis of the normative data obtained, reference values for radiographic parameters of femoroacetabular impingement morphology should be redefined. Normal values for a Tonnis angle were between –8° and 14°, the upper limit of the center-edge angle was 44°, and the normal values for femoral neck-shaft angle were between 121° and 144°. Surgical indications should be tailored to physical examination findings and not radiographic findings alone. Level of Evidence: Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Protrusio acetabuli (PA) is a complication of many disorders involving the hip joint. Its frequency and clinical features in seronegative sponyloarthropathy (SNSA) are unknown. The prevalence and characteristics of PA were studied in 50 adults and 25 children with SNSA (40 ankylosing spondylitis, 24 psoriatic arthropathy, and 11 Reiter's syndrome). PA was considered present when the acetabular line medially exceeded the ilioischial line by 3 mm or more in men, 6 mm or more in women, more than 1 mm in boys, and more than 3 mm in girls. PA prevalence was 25% in the total group (19 of 75 patients), 22% in adults, and 32% in children. There were no significant differences in seronegative disease type; PA was present with similar frequency between genders and did not correlate with disease duration, clinical severity of hip involvement, or previous medication. Radiological damage was similar in adults and children and did not differ in those with and without PA. Similarly, functional capacity did not differ between groups. It is concluded that PA is a frequent complication in SNSA; however, its presence does not seem to modify the functional prognosis of these patients.

Acetabular protrusion (PA) as measured by a line crossing method was studied in 73 patients with juvenile rheumatoid arthritis (JRA) and its frequency found to be 12% (9/73), presenting bilaterally in 5 cases and unilaterally in 4. All patients had some other forms of radiological damage and the presence of PA was predominantly observed in the JRA group with greater age at onset (8 vs 4.2 years; p

Protrusio acetabuli (PA) in neurofibromatosis is not well documented in the literature. Two forms of PA, a nondysplastic and dysplastic type, are noted. Twenty-one percent of hips (13 patients) in neurofibromatosis were found to have some form of acetabular protrusion abnormality. In the control group (83 patients) without stigmata of neurofibromatosis, only 9% of hips were associated with PA. The progressive dysplastic form of PA is usually associated with contiguous soft-tissue neurofibromas and lumbar dural ectasia. The nondysplastic, nonprogressive form has less of an association with regional soft-tissue abnormalities and almost no association with dural dysplasia.

In a retrospective study of 100 patients with adult rheumatoid arthritis, 23/100 (23%) were found presenting protrusio acetabuli (PA). PA of the hips was present in 28/193 (14.5%). This complication was more frequent in females, with 19/23 cases (82%), and its presence and severity were associated with longer duration of disease. On analysing the probable relationship between PA and glucocorticoid intake, no statistically significant differences were found between patients who had received such drugs and those who had not. With the method employed and in a selected rheumatoid arthritis population, PA was found in high prevalence.

Extreme bilateral protrusio acetabuli is an unusual complication of hematologic disease. We have described a patient with sickle cell anemia who had this complication probably as a result of osteopenia. Thus sickle cell anemia should be added to the list of potential causes of protrusio acetabuli.

The normal values of the radiological lines most frequently used as references in the diagnosis of adult protrusio acetabuli were prospectively determined in 150 children (300 hips) without femoral pathology and aged between 2 and 15 years, mean age 8 years. The teardrop shape was modified according to the child's age, the "crossed" type predominating (48.7%). The mean centre edge (CE) angle fluctuated, with a median value of 31.2 degrees +/- 6.2 degrees, increasing with age and with slightly greater values in females; a large spread of CE angle values was observed within age groups. Acetabular ilioischial line values ranged from +7 to -5 mm, with a mean of +1.8 +/- 2 mm. This last method was the most suitable because it was not modified by changes in incidence of X-rays in radiological studies. With this method protrusio is diagnosed in children when the acetabular line is projected medially, provided that the ilioischial line is 1 or 3 mm or more for boys and girls, respectively. We conclude that the most trustworthy method available to evaluate PA in children should be "line crossing".

Hip radiographs were examined in forty patients with rheumatoid arthritis who had total hip arthroplasties. The patients' ages ranged from 37 to 83 years.Radiological appearances of hip involvement was calssified into five types as described by Lowe et al. Radiographic evaluation showed that protrusio acetabuli and loss of joint space were seen in 45% and 28%, respectively. Types of hip involvement correlated with the serum level of CRP and type of joint destruction (LES, MES, MUD), but not with disease duration, maintenance dose of corticosteroids and JOA score. 70% of the patients with protrusio acetabuli were MUD type and most with loss of joint space were LES or MES type.

Marfan syndrome is an autosomal dominant disorder of connective tissue, with ocular, skeletal, and cardiovascular manifestations. Protrusio acetabuli is a criterion for the diagnosis of Marfan syndrome. Prolonged protrusio acetabuli may result in secondary osteoarthritic changes in the hip joint. Radiographic criteria for protrusio acetabuli include an abnormally positioned acetabular line, a center-edge angle of Wiberg of >40 degrees, and crossing of the teardrop by the ilioischial line. In a skeletally immature patient with Marfan syndrome in whom the triradiate physis of the acetabulum is still open, closure of the triradiate physis can interrupt and decrease the progression of the deformity. In older patients, valgus intertrochanteric osteotomy and eventually total hip arthroplasty are the only methods available for correction of the protrusio acetabuli.

Background: Bipolar hip arthroplasty was devised for fracture neck femur in elderly patients. Subsequently, indications have been expanded to include conditions affecting acetabulum like rheumatoid arthritis, osteoarthritis and avascular necrosis of femoral head. Materials and methods: We have studied the results of bipolar hip arthroplasty in 38 such patients, with severely involved acetabulum due to rheumatoid arthritis, avascular necrosis of femoral head and primary osteoarthritis. Acetabulum was reamed to get a tight 'equatorial' or 'rim' fit of the prosthesis. Prosthesis selected was 1 mm bigger than the maximum size of reamer used. Cement was used in femur whenever there was marked osteoporosis or wide medullary canal. Post operatively all patients were regularly screened for pain, range of movement, protrusio acetabuli, loosening / sinking of prosthesis and radiographic assessment of movement in the two bearings of prosthesis. Results: Overall results achieved were good to excellent in 80% of patients. Conclusions: The ultimate outcome is comparable to total hip arthroplasty. The added advantage is of low cost, simplicity of procedure and easy future revision.

Forty-four children with neurofibromatosis were found to have three previously underdescribed conditions: thoracic lordoscoliosis, protrusio acetabuli, and monomelia neurofibromatosis. Thirty-four patients (77%) had scoliosis; of these, nine had dystrophic scoliosis (Group I, 26%), six had dystrophic lordoscoliosis (Group II, 18%), eight had dystrophic kyphoscoliosis (Group III, 24%), and 11 had nondystrophic scoliosis (Group IV, 32%). Group III curves were severe and progressive, rendering them difficult to stabilize even with anterior and posterior spinal fusions. Group II curves were progressive but stabilized by posterior spinal fusion alone. Group I curves were less progressive than Groups II and III, but required surgery more often than those of Group IV, which were generally controlled by orthoses. Protrusio acetabuli of varying severity occurred in 13 patients (21 hips). Three patients had involvement of a single limb (monomelic neurofibromatosis).

Thirty-six patients with the phenotypic features of Marfan's syndrome (arachnodactyly, abnormal ratio of arm span to height, ligamentous laxity, and tall stature) were evaluated and classified into three groups. Group 1 represented definite Marfan's syndrome and included patients with two or more major signs, with additional minor signs as described by McKusick (18 patients). Group 2 represented probable Marfan's syndrome and included patients with one major sign and multiple minor signs (nine patients). Group 3 represented the Marfan phenotype and included patients with multiple minor signs (nine patients). A high incidence of scoliosis occurred in all groups (100% in Group 1 and 89% in Groups 2 and 3 combined). Group 1 patients had longer, multiple, and more progressive spinal curves. Protrusio acetabuli (Type II and III hips) was present in 22 patients (11 in Group 1, six in Group 2, and five in Group 3), with more severe involvement noted in Group 1. Foot deformities of varying types and severity occurred in all groups but were seen most often in Group 1 patients. Patients with the features of Marfan's syndrome (even without major diagnostic criteria) have a high incidence of progressive scoliosis, protrusio acetabuli, and foot deformities.

Seven hips with protrusio acetabuli which showed complete or partial resolution of the protrusion after replacement with Ring's prosthesis are reported. It is suggested that this prosthesis offers a simple and effective method of treating painful protrusion into the pelvis; it allows healing of the medial wall of the acetabulum while avoiding many of the hazards of other methods of treatment.

This paper describes 26 adolescents presenting with hip pain. Monarticular hip arthritis can be the onset of juvenile spondylitis or even juvenile rheumatoid arthritis, whilst occasionally it persists as localized disease which becomes destructive; however, in this small series, the two commonest diagnoses were idiopathic protrusio acetabuli and idiopathic chondrolysis. Initial diagnosis may be difficult despite adequate investigation and exclusion of infection. In such cases long-term follow-up with appropriate orthopaedic advice is essential.

We are reporting the results of a finite-element analysis of acetabular reconstruction for total hip replacement in the presence of protrusio acetabuli. In a protruded acetabulum, cortical bone stresses on the medial part of the pelvic wall increase with medial placement of the acetabular component, while normal placement of the component (more lateral placement) reduces these stresses. Metal backing of a polyethylene acetabular component causes a reduction in the peak cement and trabecular-bone stresses. A metal protrusio ring about only the periphery of the acetabular component increases stress levels within the lateral part of the pelvic cortex and has little effect on stresses in the medial part of the pelvic wall. A complete metal protrusio cup increases stresses in the lateral part of the pelvic cortex while decreasing substantially the stresses in the medial part of the cortex and the trabecular bone. Prosthetic reinforcement of the medial part of the acetabular wall has little effect on stress patterns in the acetabular region. Clinical Relevance: The major long-term problem with cemented total hip prostheses is loosening. Loosening is probably related in part to the stress state in the cement and surrounding bone. The protruded acetabulum is particularly difficult to reconstruct in a manner that ensures longevity of the total hip replacement. In patients with protrusio acetabuli, the prosthetic acetabulum should be placed in a normal and not in a protruded position. A metal-backed acetabular component or a complete metal cup incorporated within the cement reduces stress levels within the medial aspect of the pelvic bone and thus may reduce the incidence of loosening.

In order to know the causes of protrusio acetabuli and destruction of the femoral head in rheumatoid arthritis, the relationship between protrusio acetabuli, destruction of the femoral head and strength of bone were examined radiologically. Material consists of 24 hips in 14 cases, which were followed up for more than 6 months. Protrusio acetabuli had a tendency to occur in the cases which have high osteoblastic response in the femoral head and severe systemic osteoporosis. On the other hand, destruction of the femoral head was hardly observed among the cases which have normotrophic osteoblastic response in the femoral head and acetabulum, but it does not related to the osteoporosis. In conclusion, it was suggested that the development of changes of the hip joint in rheumatoid arthritis was related to the bone strength of the hip and systemic osteoporosis.

Pelvic radiographs of 200 consecutive Japanese Oriental patients who were admitted for hip surgery at the Hospital of Kobe University in Japan were compared with those of 199 consecutive American white patients who were admitted for the same purpose to a New England hospital over a similar four and a half-year period between 1972 and 1976. One hundred and fifty-three Japanese Oriental and 157 American white patients had either primary or secondary osteoarthritis. The remainder had other types of hip pathology, such as avascular necrosis, rheumatoid arthritis, and ankylosing spondylitis. The radiographs of five Japanese Oriental and seven American white patients showed evidence of previous Legg-Calve-Perthes disease, coxa vara, or slipped capital femoral epiphysis. With only two exceptions, the osteoarthritis in the remainder of the Japanese Oriental patients was secondary, caused by antecedent congenital hip disease: twenty-eight had one or two congenitally dislocated hips, ninety-two had acetabular dysplasia, and twenty-six had superolateral osteoarthritis. In contrast, only nine of the American white patients clearly had a diagnosis of acetabular dysplasia, and twenty-six had superolateral osteoarthritis. Twenty-one American white men had a femoral head-tilt deformity. Among the Americans, the largest group (sixty-five patients) had superomedial osteoarthritis. Nine had non-rheumatoid protrusio acetabuli and twenty had axillary or concentric osteoarthritic involvement. The majority of American white patients, therefore, had a type of osteoarthritis that was not seen in the Japanese Oriental patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Normal radiographic anatomic relationships, as well as distortion of those relationships in protrusio acetabuli, have been described. The occurrence of this deformity in arthropathies is stressed and other entities are mentioned and illustrated. Standard anteroposterior hip or pelvis radiographs readily permit the detection of protrusio acetabuli.

We reviewed our experience with total hip replacement for coxarthrosis due to Paget's disease. The clinical and radiographic results in twenty-one patients who had a total hip replacement between October 1972 and February 1982 were analyzed. The ages of the patients averaged 68.6 years (range, fifty-seven to eighty years) and there were twelve women and nine men. The follow-up averaged five years and two months (range, two years to eleven years and four months). A good or excellent result was achieved in eighteen patients. Of the other three patients, two required a revision operation at two and one-half and five years postoperatively for symptomatic mechanical loosening of the femoral component. The remaining patient had a fair result because of activity of the Paget's disease. Special problems that we encountered included varus deformity of the proximal end of the femur predisposing to varus placement of the femoral component, protrusio acetabuli, increased blood loss, sclerotic bone that made reaming difficult, and heterotopic ossification.

The family of a child who developed symptoms and flexion contractures with protrusio acetabuli rapidly between the age of 8 and 11 was examined. The mother and one sib showed limitation of hip movements, while radiological criteria for protrusio were found in the mother and 4 of the proband's 8 sibs; only one had complained of pain. At the age of 16 the proband underwent bilateral total replacement arthroplasty; histologically the changes were those of fibrocartilaginous replacement and osteophyte formation.

Thirty-five children who had rheumatoid arthritis were followed for three to twenty-two years. Four categories of involvement of the hip were seen. In the first group, thirteen patients had mild disability and slight radiographic changes. In six of those patients the disease was in remission at the time of writing, and the patients were asymptomatic. In the second group, two patients had episodic disability that correlated with the activity of the disease. In the third group, fourteen patients had progressive disability and radiographic changes. Fifty-five of the fifty-nine procedures that were performed on the hip and knee in this series were done on those fourteen patients. In the fourth group, six patients had dramatic clinical and radiographic findings but, at the time of the latest follow-up, had little functional disability. In all six of these patients, the disease was in remission. In the children in this study, protrusio acetabuli was more cephalad than has been found in adults who have rheumatoid arthritis. All of the children had psychosocial problems, but they responded well to counseling. These problems influenced the timing of the surgical treatment.

Since 1971 we have used homologous and autogenous bone grafts to reinforce the medial acetabular wall when doing a total hip replacement in patients with painful protrusio acetabuli. Thirty-two patients have been followed for a minimum of two years, the longest follow-up being eight years. All grafts appeared to have united roentgeno-graphically within three months, and the protrusion did not progress. In seven patients with a completely absent medial acetabular wall, a protrusio acetabuli ring was used to provide support until the bone graft had healed. Complications included one late dislocation, one pulmonary embolus, two trochanteric non-unins, two fractured trochanters, and one case of loosening of the femoral component. The results of this study suggest that bone-grafting is effective in arresting the progression of acetabular protrusion.

Thirty-five total hip arthroplasties done in twenty-five patients with protrusio acetabuli secondary to rheumatoid arthritis were reviewed. There was an average follow-up of 4.3 years, with a range of three to seven years. The results were rated as excellent or good in 66 per cent, fair in 26 per cent, and poor in 8 per cent. Although 100 per cent demonstrated cementbone interface demarcation around the acetabular component, only 10 per cent showed progression of the line of demarcation to two millimeters and one had acetabular loosening with migration. Eight per cent showed femoral loosening or subsidence; 8 per cent, calcar resorption; and 6 per cent, a receding cortex with cystic changes. Twenty-three per cent had nonunion of the greater torchanter after trochanteric osteotomy. Type-III cement-bone interface demarcation was present around the acetabular component was positioned one centimeter superiorly or medially beyond the anatomical position, as estimated by the method described. In thirteen hips in which the acetabular component was positioned within five millimeters of the anatomical position, no Type-III demarcation was present. Better fixation and position of the acetabular component is achieved by the use of a bone graft or a special titanium perforated-sheet mesh, or both, or by an acetabular shell. The use of three wires improved trochanteric fixation.

A high percentage of hips in patients with rheumatoid arthritis presenting for total joint replacement have protrusio deformity with extremely thin medial acetabular walls. Biomechanical principles suggest that, to prevent inward migration of the acetabular component, the prosthesis should be positioned laterally near the acetabular rim. To reinforce the medial wall, the femoral head is fashioned into a solid graft which is anchored against the medial wall as a plug, minimising the amount of cement used and making the use of wire mesh and restraining rings about the acetabulum unnecessary. A series of nine operations on seven patients is presented. Serial radiographs, tomograms and scintigrams taken after operation suggest satisfactory incorporation of the grafts, and no complications have been encountered in a follow-up period ranging from three months to two years.