Both osteochondritis dissecans and coxa plana are diseases with identical pathological changes, namely avascular necrosis. Although the etiology is not known in either case, it seems likely that when the etiological factors are fully determined they will prove to be applicable to either condition. The relative importance of each etiological factor in the multiple pathogenesis of these two conditions is almost certainly different in each disease process, and probably in each individual case. Present day concepts suggest that there is an underlying constitutional disturbance, which is associated with other factors (of which trauma is almost universally accepted as being one; perhaps the only one), to predispose the individual to these conditions. It is hoped that further studies along these lines will not only help to provide a better understanding of the two conditions mentioned above, but will also be of value in the appreciation of the pathogenesis and etiology of a large number of disturbances including such varied conditions as dysplasia epiphysialis multiplex congenita, cretinoid dysgenesis of the capital femoral epiphysis, adolescent coxa vara, transient synovitis of the hip, and the recently discussed (Merle d'Aubigné 1964) idiopathic avascular necrosis of the femoral head in adults. That there is an etiological relationship between osteochondritis dissecans and coxa plana seems clear, but much more work is required before we will have at hand the patho-physiological evidence that will permit an accurate correlation of these two conditions

Specimens of femoral heads were studied at necropsy in two cases of Legg-Calve-Perthes' disease. One was that of a boy aged four years ten months who died from appendicitis; the other was from a boy aged six years who died from a malignant glioma. Both had been treated for one and a half years for Legg-Calve-Perthes' disease which was in a stage of repair at the time of death. The diseased femoral heads were moderately flattened but the surface cartilage was intact. Epiphysial bone and bone marrow were partly replaced by cartilage, fibrous tissue and granulation tissue, and new bone was being formed. Inflammatory reaction was inconspicuous. Enchondral bone formation was only slightly decreased, and the structure of the growth plate was undisturbed. There was no sign of systemic bone disease. In the first case the changes indicated that more than one episode of ischaemia had occurred, and an occlusion--probably from an old thrombus--was demonstrated in the posterior inferior retinacular artery of the femoral head. The last episode of ischaemia, furthermore, had caused infarction of part of the metaphysial bone. In both cases, the central area of the metaphysial bone of the affected femur contained fat, but there were few haemopoietic cells and it therefore looked pale. The findings are discussed in relation to previous work on the pathology in Legg-Calve-Perthes' disease, recent information on the vascularisation of the femoral head in children, and experimental and comparative animal studies

A review of fifty cases of idiopathic pseudocoxalgia (Legg-Calvé-Perthes disease) followed into adult life for periods of eleven to thirty years (average seventeen years) after diagnosis shows:. 1. In the whole series rather more than one-third of the patients developed hips which were normal or nearly normal. 2. An equal number had hips which could only have been considered "fair.". 3. About one quarter had hips which gave pain and which showed marked loss of movement and gross degenerative changes radiologically. Judged from the point of view of symptoms, the results were better than the foregoing would suggest. Three-quarters of the patients were fully active and free from pain but only two-fifths had hips which were radiologically good. It is possible that such apparently good results are unlikely to be permanent, and I hope, therefore, to continue this follow-up for another ten or fifteen years. It can, however, be concluded at this stage that an immediate good result is likely to be maintained at least until the age of twenty-five years, even though half of such patients will have radiologically abnormal hips. There is a characteristic pattern of deformation of the femoral head and neck in the adult resulting from this condition in childhood, based on the degree of flattening of the head and shortening of the neck. The end-results are better in adequately treated cases. Two cases are reported in which osteochondritis dissecans developed as a late complication

We have been following all modern trends in the treatment of Legg-Calve-Perthes disease during several decades (from nonoperative treatment, revascularization procedures, varization femoral osteotomies to various pelvic osteotomies). Last few years we have started to use triple pelvic osteotomy in patients older than seven years, in order to shorten treatment period, establish solid containment and subsequent remodelation of femoral head, and achieve final spheric hip congruence. In the period from 1996 to 2004 we had 28 such surgical interventions. Patient age at surgery was between 7 and 10 years. All hips were uncontained preoperatively, and in fragmentation stage. Twelve hips were classified as Catterall group III and sixteen hips as Catterall group IV. Triple pelvic osteotomy according to Tonnis (modified by Vladimirov) was performed in all cases. Average follow-up period was 40 (28–96) months. Treatment result was good in all patients, with full functional recovery. Spheric joint congruence was achieved in 24, and aspheric congruence in other 4 cases. Average period for union of osteotomies was 10 weeks, followed by introduction of full weight bearing, considerably earlier than in patients with similar age and disease stage, treated by combination of Salter pelvic osteotomy and femoral shortening

This pilot study aims to investigate the utility and feasibility of a unique upright MR scan for imaging hips affected by Legg-Calve-Perthes Disease (LCPD) with patient standing up, in comparison to the standard supine scans. Protocol development using this unique upright MRI included healthy adult and child volunteers. Optimum patient positioning in a comparable way between supine to standing was assessed. The balance between shorter scan time (to what a child can tolerate) and longer scan time (for better image acquisition). The study protocol has begun in 2 children with LCPD. Patient recruitment continues. Early results indicate a dynamic deformity of the femoral head in early stage LCP disease. Femoral epiphysis height decreased on standing (7.8 to 6.8mm), width increased on standing (16.6 to 20.9mm) and lateral extrusion increased (3.5 to 4.1mm). Overall epiphyseal shape changed from trapezoidal (LCP femoral head when supine) to flattened triangular (LCP femoral head when standing). Differences were thus demonstrated in all parameters of bony epiphyseal height, width, extrusion and shape of a femoral head with LCP Disease when the child stood and loaded the affected hip. Satisfactory image acquisition was possible with Coronal T1 GFE sequences, with both hips in the Field of View. 2.5min scans were performed with the child standing first, then supine. Hip position was comparable when standing and supine. Longer scans were not tolerated by younger children, more so those with LCP disease. To our knowledge this is the first reported use of standing MRI in LCPD. A dynamic deformity has been demonstrated, with flattening, widening and worsened lateral extrusion when the child is standing compared to supine. This proof of concept investigation demonstrates the feasibility of upright MRI scanning and may demonstrate previously undetected deformity

Introduction. Legg-Calve-Perthes disease (LCPD), a juvenile osteonecrosis of the femoral head (ONFH), can remain sequelae around hip joint, and results in osteoarthritis necessitating total hip arthroplasty (THA) in middle-age. THA for sequelae of LCPD needs specific concerns for anatomical deformity, leg length discrepancy (LLD), and relatively young patient's age. To date, few studies are available for the results of THA for LCPD sequelae. Moreover, there was no study for the result of Alumina-Alumina THA (Al-Al THA) in patient with LCPD sequelae, even excellent long term outcome of Al-Al THA has been documented in relatively young patients. The aim of this retrospective study is to evaluate the clinical and radiological outcome of Al-Al THA for LCPD sequelae, especially in terms of the restoration of LLD and the occurrence of complication. In addition, we compared the results of THA for LCPD sequelae with those for adult onset ONFH, in which THA is necessitated in relatively young age and excellent long term outcome has been proven after Al-Al THA. Method. Between 1997 and 2007, 41 cementless Al-Al THA were performed in 37 patients with LCPD sequelae and followed up for mean, 10.4 years. Mean age at THA was 43.6 years. Using the propensity score matching with age, gender, and the length of follow-up as variables, 41 THAs in 37 patients were identified from 339 hips in 256 patients who underwent primary Al-Al THA for ONFH during the same period. Clinical and radiological outcomes in terms of implant survival, Harris hip score (HHS), LLD change, and perioperative complication were compared between the two groups. Results. In LCPD group, there was no revision during follow-up period. All stems and cups were survived without osteolysis or loosening at last follow-up. HHS increased significantly from 70.9±12.9 point to 97.4±5.4 point (p<0.001). LLD decreased significantly from 2.0±1.2 cm to 0.2±0.9 cm. (p<0.001). Fourteen intraoperative femoral cracks occurred. One patient showed peroneal nerve palsy after surgery. There was one patient with deep vein thrombosis without pulmonary embolism. In ONFH group, there was also no revision during follow-up and all implant was radiologically stable without evidence of osteolysis or loosening. HHS increased significantly from 44.9±21.4 point to 96.6±4.6 point (p<0.001). LLD decreased significantly from 0.5±0.8 cm to 0.1±0.9 cm. There were 6 intraoperative femoral fractures. Also, there was 2 more postoperative periprosthetic fractures after trauma and 1 postoperative dislocation. Even the implant survival was not different between two groups, LCPD group showed higher rate of overall complication (p=0.04) and intraoperative femoral fracture (p=0.027) than ONFH group. Conclusion. Outcomes of Al-Al THA in patients with sequelae of LCPD were comparable to those in patients with ONFH clinically and radiologically. LLD was restored after THA without troublesome neurologic complication in both groups. Although high rate of intraoperative femoral crack was revealed in LCPD group, fracture union was achieved in all hips without stem loosening. As with ONFH, Al-Al THA may be a reliable treatment option for the patients with LCPD sequelae

Subtrochanteric osteotomy has been reported to interrupt the destructive phase of coxa plana and speed up the rate of healing. The aim of this investigation was to test the validity of these statements. The material comprised twenty-five patients treated by osteotomy and thirty-three patients treated by support in a Thomas's splint. For every patient the extent of the radiological changes was estimated and plotted against time as a percentage of the normal epiphysial volume. The graph so obtained represents the rate of destruction and re-ossification, as well as the maximum involvement of the epiphysis. The curves for each group of patients were superimposed in a graph with all the minima coincident in time. The two patterns of curves are closely similar. It was confirmed statistically that the rates of destruction and re-ossification did not differ between the two groups. The results afford no evidence that osteotomy interrupts the disease or speeds up healing

Introduction: Shortening of the affected limb has frequently been observed in children with Legg-Calvé-Perthes disease (LCPD). Many factors have been thought as the cause of this residual shortening after LCPD. There has been no clear answer regarding which is more responsible for the residual shortening between coxa plana and the disturbed physeal growth. To clarify the main cause of residual shortening, clinical and experimental studies were conducted. Materials and Methods: For clinical study, 40 LCPD children with definite shortening were evaluated. This included 20 children with active disease and 20 children at skeletal maturity. Teleoroentgenograms were obtained for all children. For the experimental study, LCPD simulation in 30 piglets was achieved by disrupting the blood supply to the capital femoral epiphysis. Results: In the clinical study, total shortening in the skeletal maturity group was 14.6 mm, which consisted of 3.2 mm (16%) shortening by decreased epiphyseal height and 11.5 mm (84%) shortening by physeal growth disturbance. Total shortening in the active disease group was 7.9 mm, which consisted of 6.4 mm (84%) decrease of epiphyseal height and 1.5 mm (16%) shortening by physeal growth disturbance. In the experimental study, overall shortening (13.6 mm) in the piglet model showed a predominance of disturbed physeal growth. The proportions were 3.2 mm (24%) by epiphyseal height decrease and 10.4 mm (76%) by physeal growth disturbance. Conclusion: Physeal growth disturbance was mostly responsible for the residual shortening following LCPD. However, in the stages of active disease, the shortening of the extremity was mainly caused by a decrease of epiphyseal height

Introduction: Evaluation of the hip joint space was performed in patients with Legg-Calve-Perthes disease in this study. Materials and Methods: Seventy-eight patients (85 affected hips and 71 unaffected hips) with LCP disease were reviewed respectively to evaluate widening of the hip joint space, the extent of epiphyseal subchondral fracture, and metaphyseal changes. The mean age of the patients was 7.4 years (range, 3–13 years). There were 27 hips at the initial stage, 23 at the fragmentation stage, and 11 at the healing stage. The metaphyseal changes in MRI scans were classified as no change, marrow edema, false cyst, and true cyst. The false cyst was defined as a cyst located at the epiphysis, physis, and metaphysis. The true cyst was defined as a cyst located within the metaphysis. Results:The widened medial joint space at the initial stage was filled with overgrown cartilage of the femoral head and acetabulum on Magnetic Resonance Imaging (MRI) and radiographs. At the fragmentation stage, there was both overgrown cartilage and markedly widened true medial joint space, which was filled with an amount of joint fluid and hypertrophied synovial tissue. Widening of the true medial joint space at the initial stage had no correlation with lateral subluxation, whereas there was a definite correlation at the fragmentation stage. In the healing stage, coxa magna contributed to lateral subluxation rather than the widening of the false medial joint space, because it had decreased or normalized because of ossification of this overgrown cartilage and normalization of the synovial hypertrophy. The overall proportion of agreement was conducted by two groups of observers according to different classification systems. The results for Catterall groups 2, 3, and 4 showed 70% agreement with the Salter-Thompson classification, 65% with the MRI classification, and 75% in the Catterall classification. The subchondral fracture line had a prognostic significance in 17 of 20 hips (85%). The MRI had a prognostic significance in 10 of 20 hips (50%). Among 85 hips, there were no changes in 32 hips, marrow edema in 13 hips, false cysts in 28 hips, and true cysts in 12 hips. Discussion: The hips without metaphyseal change had less involvement of the epiphysis compared to the hips with the metaphyseal change. Metaphyseal cysts disappeared on radiographs and MRI scans during the healing or remodeling stage

Purpose of study: To test the hypothesis that previous hip involvement leads to earlier presentation and a better outcome for the contra-lateral hip in bilateral Legg-Calve-Perthes’ disease (LCPD). Method: Case notes and radiographs of 250 patients with LCPD treated by a single surgeon between 1984 and 2003 were retrospectively reviewed. Thirty three patients (4 girls: 29 boys) with a minimum 1 year follow-up were identified with bilateral involvement from a prospectively collected database. Patients were grouped according to age at presentation (Group A-< 6 years; Group B- 6–8 years; Group C-> 8 years). All radiographs were reviewed and consensus was obtained on the presenting Waldenstrom stages. The severity of disease was rated by Catterall and lateral pillar classifications. The outcome was determined by the Stulberg classification. The right hip was the first affected in 25 of the 33 hips. Results: These are summarized below. Conclusions: The present report, with 33 patients, is the second largest series of patients with bilateral LCPD to our knowledge. The second hip involvement was milder than the first, but the improvement in outcome was statistically insignificant

LCPD can cause femoral head deformity and osteoarthritis requiring total hip replacement (THR). Currently, there is little data on how patients are functioning after a THR from patients’ perspective. The purpose of this study was to collect a large patient-reported outcome data set on adults with LCPD, including those who had a THR, using a Web-survey method and to compare their outcomes to a normative population.

An English REDCap-based survey was built and made available on a LCPD study group website. The survey included childhood and adult LCPD history, SF-36 Health Survey, and the Hip Disability and Osteoarthritis Outcome Score (HOOS). Statistical analysis included t-test and linear and proportional odds regressions.

Of the 1182 participants who completed the survey, 261 participants (89 M, 172 F) had a THR. The mean age at survey was 44.6±12.4 years (range 20–79). The mean duration since THR was 7.2±8 years (median 4, range 0–43). Gender and age matched analysis showed that THR participants had significantly lower HOOS Quality-of-Life and Sports scores (p<0.0001) for all age groups in comparison to a normative cohort. In women, the HOOS Symptoms, Daily Living, and Pain scores were also significantly lower in the <55 age groups (p<0.05). Similarly, SF-36 scores were significantly lower (p<0.05) in female <45 age groups in 5 out of 8 SF-36 scales. Overall, hip dysplasia and the number of years-from-THR were the main factors associated with worse SF-36 and HOOS scores. In comparison to the non-THR participants, THR participants had higher scores in some of the HOOS and SF-36 scales.

LCPD participants with THR had significantly worse HOOS and SF-36 scores in most of the scales studied than a normative cohort, especially in women. There is significant disability even after a THR, warranting continued efforts to improve treatment and outcome.

The most important outcome predictor of Legg-Calvé-Perthes disease (LCPD) is the shape of the healed femoral head. However, the deformity of the femoral head is currently evaluated by non-reproducible, categorical, and qualitative classifications. In this regard, recent advances in computer vision might provide the opportunity to automatically detect and delineate the outlines of bone in radiographic images for calculating a continuous measure of femoral head deformity. This study aimed to construct a pipeline for accurately detecting and delineating the proximal femur in radiographs of LCPD patients employing existing algorithms. To detect the proximal femur, the pretrained stateof-the-art object detection model, YOLOv5, was trained on 1580 manually annotated radiographs, validated on 338 radiographs, and tested on 338 radiographs. Additionally, 200 radiographs of shoulders and chests were added to the dataset to make the model more robust to false positives and increase generalizability. The convolutional neural network architecture, U-Net, was then employed to segment the detected proximal femur. The network was trained on 80 manually annotated radiographs using real-time data augmentation to increase the number of training images and enhance the generalizability of the segmentation model. The network was validated on 60 radiographs and tested on 60 radiographs. The object detection model achieved a mean Average Precision (mAP) of 0.998 using an Intersection over Union (IoU) threshold of 0.5, and a mAP of 0.712 over IoU thresholds of 0.5 to 0.95 on the test set. The segmentation model achieved an accuracy score of 0.912, a Dice Coefficient of 0.937, and a binary IoU score of 0.854 on the test set. The proposed fully automatic proximal femur detection and segmentation system provides a promising method for accurately detecting and delineating the proximal femoral bone contour in radiographic images, which is necessary for further image analysis.

Introduction: The aim of this paper was to present a profile of Legg-Calve-Perthes’ (LCP) disease and test the hypothesis of an association between LCP disease and poverty.

Methods: We examined demographic data on a group of 240 children (263 hips) presenting with LCP disease in Greater Glasgow, where the mean deprivation scores are substantially greater than in the rest of Scotland, to see if this association applies or whether other clues to the aetiology of LCP could be divined.

Results: There were 197 males and 43 females. The majority presented in the sclerosis phase with much smaller numbers in the other phases. 70 % (184 cases of LCP) were Catterall grades 3 or 4. 16.25% had a family history of LCP. Bone age in our series is heavily skewed towards the lower centiles. The number of siblings in the family averaged 1.9, with 13 % being an only child. The maternal age at birth of the index child showed no preponderance to older age. Maternal smoking during and after pregnancy was noted in 55 %, which compares with 52% reported in the population of Greater Glasgow in general. Bone age in our series was heavily skewed towards the lower centiles. Birth weight showed a definite shift to the left, height a weaker shift to the left. 25 % of the children in our series are in social class IV and V, although this accounts for more than 50 % of the population of the Greater Glasgow.

Discussion: There is no significant evidence of a preponderance of LCP disease in the most deprived groups (p=0.9). The aetiology of LCP disease is likely to be multifactorial and may include a genetic or deprivation influence causing low bone age, hyperactivity and a high pain threshold.

Introduction: The incidence of Legg-Calvé-Perthes Disease (LCPD) has varied considerably both between countries and between population groups. The incidence of LCPD has not been reported in Korea. The purpose of this study was to determine the annual incidence of LCPD in Korea and to compare this to other population groups.

Materials and Methods: Firstly, only LCPD children who were living in Chonnam Province, Korea, and were aged 14 years and under during the years 1999, 2000, and 2001, were reviewed to measure the annual incidence. Secondly, for a further study regarding the variables related to the epidemiological interest, 816 hips, which were treated at our hospital during the last 32 years from 1972 to 2003, were reviewed.

Results: The population aged 14 years and under was 734,645 in 1999, 728,721 in 2000, and 719,504 in 2001. Among them, the number of LCPD children was 29 in 1999, 28 in 2000, and 24 in 2001. The annual incidence was 3.9 per 100, 000 in 1999, 3.8 in 2000, and 3.3 in 2001, with a mean incidence of 3.7 per 100, 000.

Discussion: The annual incidence of LCPD in Korean children aged 14 years and under was 3.7 per 100,000. This Korean incidence was lower than the 5.1 to 21.1 per 100,000 incidence reported in Caucasians and higher than the 0.45/100,000 reported in blacks or mixed decent. The incidence of gender, bilaterally, age of disease onset, extent of head involvement, and other related epidemiological parameters was similar to those reported in other studies.

Treatment of severe Perthes disease remains a major challenge. Various surgical options exist for containment. We describe the Birmingham interlocking triple pelvic osteotomy (BITPO) and report the results at skeletal maturity.

We reviewed 22 hips in 21 consecutive patients with severe Perthes who had the BITPO. There were 16 males and 5 females. The mean age at presentation was 7 years 7 months. Seventeen hips were Herring group C and five were Herring group B. Six patients had four head-at-risk signs (HARS), 9 had three HARS, 4 had two HARS and 3 had a single HARS. The mean age at operation was 8 years 2 Months.

Clinical, radiological and functional evaluations were under taken on these patients who have since reached skeletal maturity. The minimum follow up was 6 years. Average age at review was 18 years 8 months (range 16–25). Two patients have since had hip resurfacing, and two patients a double femoral osteotomy and one patient a surgical dislocation of the hip and valgus osteotomy.

The average Harris Hip Score pre-operatively was 52, which improved to a mean score of 82. Eleven hips were classified as Stulberg I/II (50%), 9 hips Stulberg III/IV (41%) and 2 hips Stulberg V (9%). The average increase in Centre-Edge angle was 31 degrees and there was an average improvement of 24.6% in the head coverage. At follow up the average abduction was 31 degrees (improvement of 8.5 degrees), internal rotation 22 degrees (10.5 degree improvement) and flexion 106 degrees (11 degree improvement).

We conclude that the Birmingham interlocking triple pelvic osteotomy provides excellent coverage of the femoral head in severe Perthes disease, recaptures and remoulds the deformed head and avoids retroversion of socket. Good results in severe Perthes disease are maintained beyond skeletal maturity.

Aims

Ganz’s studies made it possible to address joint deformities on both the femoral and acetabular side brought about by Perthes’ disease. Femoral head reduction osteotomy (FHRO) was developed to improve joint congruency, along with periacetabular osteotomy (PAO), which may enhance coverage and containment. The purpose of this study is to show the clinical and morphological outcomes of the technique and the use of an implemented planning approach.

Introduction: The authors introduce a modified technique of iliac splitting and expanding shelf (ISES) arthroplasty for severe LCPD, and report on the intermediate outcomes.

Materials and Methods: This new procedure is a modification of the previously reported tectoplasty of Saito (1986) and the shelf arthroplasty of Catterall (1992). Only the sartorius muscle and the indirect head of the rectus femoris muscle are detached, leaving the abductors intact. A superiorly hinged bony flap was raised from the lateral iliac wall just above the hip joint capsule. A corticocancellous bone plate was harvested from the inner table of the iliac wing, and was placed between the lateral hip joint capsule and the bony flap. The triangular space between the split iliac wall and the bone plate was packed with autogenous cancellous bone chips and Osteoset® (Wright-Medical, Arlington, Tennessee, USA). The repaired indirect head of the rectus femoris muscle gave stability to the shelf. After 4 weeks in a Petrie cast, the hip was mobilized, and partial weight bearing was started postoperative at 6 weeks. Twenty one hips in 21 children older than 8 years presenting with early (18 hips) and late (reossification) (3 hips) LCPD were treated by ISES arthroplasty. All patients were followed up for more than 2 years (range, 2 to 8.5 years).

Results: There were significant functional and radiological improvements after operation. One patient needed a secondary varus osteotomy to solve persistent subluxation. The poorest result occurred in a very obese child, presenting with early stage of Catterall IV involvement at age 11.5 years.

Discussion: Our modified technique of the shelf arthroplasty, sparing the abductor mechanism, appears to be a reliable and effective method to augment the superolateral coverage of the femoral head in severe LCPD.

Introduction: The aim of this paper was to test the hypothesis that for hips affected with Legg-Calve-Perthes’ (LCP) disease under the age of 8 years, surgery does not affect the outcome.

Methods: We performed a retrospective paired study of patients, who were diagnosed with LCP disease before the age of 8 years, to compare the radiological results after treatment between conservatively and surgicallytreated groups. One patient was selected from each group to create the pairs for this study. Each pair was strictly matched for gender, body mass index, age at onset, and stage at the first visit, Catterall and Herring grading and radiological at-risk signs. Each pair was assessed by comparing the values of five radiological measurements.

Results: From a cohort of 345 hips diagnosed with LCP disease 14 pairs (28 hips) fitted the criteria. The radiological measurements, which showed a statistically better result in the surgical groups, were Mose’s method (p = 0.019), the Acetabular-Head Index (p = 0.034). There were no statistical differences in the Slope of the Acetabular Roof (p = 0.37), Articulotrochanteric distance (p = 0.17) and Stulberg grading (p = 0.2). 5 pairs had a better Stulberg result in the operative group. Three of these 5 pairs were less than 6.5 years at the time of their surgical procedure. Three pairs had a better Stulberg result in the conservative group. Six pairs had no difference between the groups.

Discussion: We conclude that surgical treatment can improve the sphericity of the femoral head and provide greater acetabular cover than conservative treatment in hips of patients less than 8 years at the onset of LCP disease. However, the Stulberg grading was not affected. Our study supports the hypothesis that for hips affected with LCP disease under the age of 8 years, surgery does not affect the outcome.

Aims

Perthes' disease (PD) is a relatively rare syndrome of idiopathic osteonecrosis of the proximal femoral epiphysis. Treatment for Perthes' disease is controversial due to the many options available, with no clear superiority of one treatment over another. Despite having few evidence-based approaches, many patients with Perthes' disease are managed surgically. Positive outcome reporting, defined as reporting a study variable producing statistically significant positive (beneficial) results, is a phenomenon that can be considered a proxy for the strength of science. This study aims to conduct a systematic literature review with the hypothesis that positive outcome reporting is frequent in studies on the treatment of Perthes' disease.