Predictors of Radial Head Dislocation in Patients with Multiple Hereditary Exostoses.

Background: Radial head dislocation in patients with multiple hereditary exostoses (MHE) is associated with loss of function and cosmetic problems. The treatment of the deformity with radial head dislocation is difficult and the timing of surgical intervention is important. The aim of this study was to evaluate the factors predictive of radial head dislocation in patients with MHE. Methods: Patients diagnosed with forearm deformity due to MHE between 1995 and 2021 were retrospectively evaluated. Radiographic parameters including radial bow (RB), ulnar bow (UB), total radial bow (TRB), total ulnar bow (TUB), percent ulnar length (PUL), ulnar shortening (US), radial articular angle (RAA), modified Masada classification and irregularity of proximal radioulnar joint (PRUJ) of the dislocated group (group D), that is subluxation or dislocation of the radial head, and the located group (group L) were compared. Results: A total of 18 patients and 25 limbs (5 girls and 13 boys) with a mean age of 10.5 years were included. There were significant differences in TUB (22.8° ± 5.6° vs. 10.7° ± 6.5°), PUL (97.5% ± 5.5% vs. 108.2% ± 7.7%) between group D and group L (p < 0.05). Moreover, irregularity of PRUJ on radiographs was more in group D (p < 0.05). Conclusions: It is possible that appropriate radiographic assessment in relation to radial head dislocation may prevent delayed surgical treatment of forearm deformities in MHE. Level of Evidence: Level IV (Diagnostic).

Medullary Compression by a Cervical Osteochondroma in a Patient with Multiple Hereditary Exostoses: A Case Report.

CASE: A 19-year-old man with Multiple Hereditary Exostoses presented with cervical pain without neurological symptoms and/or signs. Magnetic resonance revealed a large C2 osteochondroma, occupying a part of the medullary canal. He was submitted to an en bloc resection with hemilaminectomy without fusion. At the 1-year follow-up, he presented resolution of pain and no neurological symptoms or signs, without cervical instability or radiological signs of disease recurrence. CONCLUSION: Cervical osteochondroma is usually asymptomatic. Neurological compression and differentiation to chondrosarcoma are the main concerns. Surgical excision allows the local cure of the disease and is usually performed without fusion.

Modified ulnar lengthening for correction of the Masada type 2 forearm deformity in hereditary multiple exostosis.

Few articles have reported on the treatment of Masada type 2 forearm deformities in hereditary multiple exostosis, possibly because of the high redislocation rate and other complications. This study precisely declares the use of modified ulnar lengthening by an Ilizarov external fixation with tumour excision for the treatment of Masada type 2 forearm deformities. 20 children with Masada type 2 forearm deformities were admitted for surgical treatment at our hospital from February 2014 to February 2021. There were 13 girls and 7 boys, ranging in age from 3.5 to 15 years (mean: 9 years) at the time of operation. We removed the prominent osteochondromas of the distal ulna and the proximal radius, positioned a classic Ilizarov external fixator on the forearm and then performed ulnar transverse one-third proximal diaphyseal subperiosteal osteotomy. We adopted modified ulnar lengthening postoperatively. The effects of surgical correction of deformity and functional improvement of the limb were assessed via regular follow-up and X-ray. The patients were followed up for 36 months, and the ulna was lengthened 26.99 mm on average; all radial heads remained relocated. The radiographic evaluations, including relative ulnar shortening, radial articular angle, and carpal slip, were improved. The functions of the elbow and forearm were all improved after surgery. Modified ulnar lengthening by an Ilizarov external fixation with tumour excision for the treatment of Masada type 2 forearm deformities in hereditary multiple exostoses has been proven to be an effective and reliable technique in the early stage.

Radiographic evaluation of ulnar deformity in patients with hereditary multiple osteochondroma and its relationship with radial head dislocation.

INTRODUCTION: In patients who have hereditary multiple osteochondroma (HMO), progressive deformity of the forearm skeleton may lead to radial head dislocation. The latter is permanent, painful and causes weakness. HYPOTHESIS: There is a relationship between the amount of ulnar deformity and the presence of radial head dislocation in patients with HMO. MATERIALS AND METHODS: This was a cross-sectional radiographic study comprising an analysis of anterior-posterior (AP) and lateral x-rays of 110 forearms in children having a mean age of 8 years and 4 months who were followed for HMO between 1961 and 2014. Four factors reflecting on the ulnar deformity in the coronal plane were investigated on the AP view and three factors in the sagittal plane were investigated on the lateral view to identify any relationship between ulnar deformity and radial head dislocation. The forearms were separated into two groups: with radial head dislocation (26 cases) and without radial head dislocation (84 cases). RESULTS: Ulnar bowing, intramedullary angle of ulnar bowing, tangent ulnar angle and overall ulnar angle were significantly higher in the group of children who had a radial head dislocation (0.05 vs 0.03, p<.001; 161 vs 167, p<001; 156 vs 162, p<001; 50 vs 30, p<.001) in univariate and multivariate analyses. DISCUSSION: Ulnar deformity, evaluated using the method described here, is more often associated with radial head dislocation than other previously published radiological parameters. This provides new insight on this phenomenon and may help to determine which factors are associated with radial head dislocation and how to prevent it. CONCLUSION: Ulnar bowing in the context of HMO, especially when evaluated on AP radiographs, is significantly associated with radial head dislocation. LEVEL OF EVIDENCE: III; case-control study.

Guided Growth Improves Coxa Valga and Hip Subluxation in Children With Hereditary Multiple Exostoses.

BACKGROUND: In children with severe hereditary multiple exostoses (HME), coxa valga, and hip subluxation are common deformities. The literatures related to surgical management and prevention of hip joint subluxation in HME are scarce. In this study, we aimed to investigate the efficacy of guided growth procedure to correct coxa valga and hip subluxation in HME patients. METHODS: We retrospectively retrieved 12 patients who received guided growth procedures for coxa valga and hip subluxation in HME patients with proximal femur exostoses with a minimum follow-up time of 2 years between 2012 and 2019. Radiographic parameters include head-shaft angle, Hilgenreiner-epiphyseal angle, acetabular index, Reimer migration percentage, center-edged angle, articulo-trochanteric distance, and femoral neck length for comparison between preoperative and latest follow-up results. It was conducted statistically by paired t test and Wilcoxon signed rank test. RESULTS: In this study, the mean difference between preoperative and latest follow-up was significant in head-shaft angle (12±5 degrees; CI, 10-14; P<0.001), Hilgenreiner-epiphyseal angle (12±5 degrees; CI, 10-15; P<0.001), and MP (7%±8%; CI, 3-11; P=0.001). There was a low revision rate (4 of 21, 19%) and no complication in our study. Compared with previous studies on guided growth in children with cerebral palsy and developmental dysplasia of the hip, our study showed good comparable outcomes. CONCLUSION: The results indicated that guided growth improves the hip radiographic parameters of children with HME and may prevent coxa valga and hip subluxations. It is a safe procedure and provides predictable results. LEVEL OF EVIDENCE: Level IV; therapeutic, case series.

Total hip arthroplasty in hereditary multiple exostosis patients: literature review and evaluation of 10 cases.

BACKGROUND: Acquired hip deformities in patients affected by hereditary multiple exostosis (HME) may incur in early hip osteoarthritis and functional limitation requiring primary total hip arthroplasty (THA). Characteristic coxo-femoral joint dysmorphisms in HME may pose a challenge for the orthopaedic surgeon. Here we report our experience in a series of patients with HME treated in our hospital with THA. METHODS: With a mean follow-up of 5 years, 10 primary THAs were reviewed; proximal femur deformities, acetabular dysplasia and joint osteoarthritis has been assessed through x-rays and CT-scan evaluation. In all cases hemispheric press-fit cups were used; 4 stem had metaphyseal engagement, 5 had proximal diaphyseal engagement and 1, with anatomical geometry, had metaphyseal fixation. 2 cases required stem cementation, 3 modular neck and 1 lateralised. The clinical data, complications and clinical outcomes, were recorded and analysed. RESULTS: The mean Harris Hip Score (HHS) increased from 34 preoperative to 86 postoperative; preoperative mean neck shaft angle (NSA) was 150°, head/neck ratio 0.6, offset 31 mm; Wiberg angle 28°, Sharp angle 38°, 1 patient had subluxation grade 4 according to Crowe, 8 hips showed osteoarthritis (Tönnis grade ⩾2 ); 5 femurs were classified as Dorr type C, 2 as type B and 3 as type A. Perioperative complications were not observed. CONCLUSIONS: Primary THA in HME significantly improved clinical and functional outcomes. Press-fit cup fixation together with metaphyseal and proximal diaphyseal stem engagement on reliable bone quality femur, represents a valid option in HME patients with normal acetabular morphology, wide broaden neck and valgus NSA.

Reliability of the Masada Classification for Forearm Involvement in Patients With Hereditary Multiple Osteochondromas (HMO).

BACKGROUND: Classifications describing forearm lesions in patients with Hereditary Multiple Osteochondromatosis (HMO) have been used to recommend surgical intervention and stratify outcomes; however, there is no consensus on which classification offers greater reliability. The purpose of this study was to determine the reliability of the Masada classification and newer classifications among pediatric hand surgeons. METHODS: One hundred one patients with HMO between June 2014 and October 2019 were enrolled in the Congenital Upper Limb Differences (CoULD) Registry. Of those, 67 patients with 101 forearms were included. Four pediatric hand surgeons from the CoULD study group undertook an online evaluation. Each rater classified radiographs according to the Masada classification. Six weeks later, raters were asked to reclassify images according to the Masada, Gottschalk, and Jo classifications. Rater agreement for these classifications was assessed by estimating Fleiss kappa along with a 95% CI. RESULTS: Interrater agreement for Masada classification after the first reading was poor (κ=0.35; 95% CI=0.30-0.41) across all raters. Interrater agreement across the 4 raters decreased for the Masada classification from the first to the second reading (κ=0.35 vs 0.21; P <0.001). Intrarater agreement for the Masada classification ranged from 0.32 to 0.63 from the first to the second study reading. Gottschalk and Jo classifications yielded significantly better interrater agreement compared with Masada (κ=0.43 vs 0.21; P <0.001). Unclassifiable cases were highest in the Masada classification (34% to 44%) and lower in the Jo (17%) and Gottschalk (14%) classifications. CONCLUSION: Despite wide use, the Masada classification was found to have low reliability when classifying forearm deformities in HMO. Gottschalk offered more options for location, yet lacked deformity description including radial head dislocation. Jo classification offered more locations than Masada and incorporated radial head dislocation in some patterns. Based on the shortcomings in all 3 classification systems, the development of a more inclusive and reliable classification is warranted. LEVEL OF EVIDENCE: Level II; Diagnostic.

Forearm deformity in multiple hereditary exostosis. Radiologic predictors of radial head dislocation.

INTRODUCTION: Radial head dislocation in patients with multiple hereditary exostosis (MHE) can lead to functional deficit. We investigated whether the location of the exostosis and certain radiological criteria predict risk of radial head dislocation/subluxation. HYPOTHESIS: We hypothesized that the radiological criteria differentiate between patients who need closer follow-up of the forearm and others for whom multiple radiographs are superfluous. PATIENTS AND METHODS: We retrospectively reviewed the demographics of patients with MHE in our hospital, and radiographic measurements were made on forearm radiographs: radial length, ulnar length, ulnar variance, radial articular angle, and radial bowing. RESULTS: Forty-nine forearms were analyzed in 30 patients. Mean age was 9.5 years at first evaluation and 11.8 years at last evaluation. Radial head dislocation or subluxation was found in 6 forearms (12%). Risk factors comprised isolated exostosis in the distal portion of the ulna or exostosis in the distal part of both the ulna and radius, radial or ulnar shortening>4.6cm, radial bowing>8.1%, radial articular angle>35°, and≥3 exostoses in the forearm. DISCUSSION: In patients with MHE with risk factors for radial head dislocation, close follow- up with regular radiography is indicated and early surgery should be performed before the radial head dislocates. LEVEL OF EVIDENCE: IV; retrospective study.

Distraction osteogenesis at the proximal third of the ulna for the treatment of Masada type I/IIb deformities in children with hereditary multiple exostoses: a retrospective review of twenty cases.

BACKGROUND: Ulna distraction by monolateral external fixator (MEFix) is a good option for the treatment of Masada type I and IIb deformities in children with hereditary multiple exostoses (HMEs). However, there is no consensus regarding where to perform ulnar osteotomy. Our hypothesis is that osteotomy at the proximal third of the ulna and progressive distraction with MEFix can simultaneously correct elbow and wrist deformities in patients with HME. METHODS: We retrospectively reviewed patients with HME who underwent ulna distraction osteogenesis from June 2014 to March 2019. The carrying angle (CA), radial articular angle (RAA), ulnar variance (UV), radial variance (RV) and range of motion (ROM) of the affected forearm and elbow were clinically assessed before lengthening and at the last follow-up visit. The total ulna lengthening distance (LD) and radiographic outcome were also recorded. RESULTS: Nineteen patients (20 forearms) with HME aged 9.1 ± 2.4 years at the time of surgery were retrospectively reviewed. The mean follow-up period was 26.1 ± 5.6 months. There were 11 patients (12 forearms) with Masada type I deformities and eight patients (8 forearms) with Masada type IIb deformities. Patients with type IIb deformity had higher RV, lower CA values, less elbow flexion and forearm pronosupination than those with type I deformity (p < 0.05); RV was an independent risk factor for radial head dislocation, with the cut off at RV > 15.5 mm. The mean LDs in patients with type I and type IIb deformities were 33.6 ± 6.6 mm and 41.4 ± 5.4 mm, respectively. The mean CA, UV, RV, forearm pronation and ulna deviation at the wrist improved significantly following surgery in all patients. In particular, five of eight patients (62.5%) with type IIb deformities had concentric reduction of the radiocapitellar joint, while no radial head subluxation was detected in patients with type I deformities at the last follow-up. Three complications were recorded: two pin-track infections and one delayed union. CONCLUSIONS: Distraction osteogenesis at the proximal third of the ulna provides satisfactory clinical and radiological outcomes in patients with Masada type I and IIb deformities. Early treatment of Masada type I deformities is indicated before progression to more complex type IIb deformities.

Lower limb deformities and limb length discrepancies in hereditary multiple exostoses.

There is a high rate of lower limb deformity and limb length discrepancy in patients with hereditary multiple exostoses (HME). The aim of this study was to evaluate the type and frequency of lower limbs axial deviation and limb length discrepancy and the type of exostoses being risk factors for theses deformities. We retrospectively reviewed standing full-length radiograph of 32 HME patients (64 limbs) followed in our institution between October 2009 and December 2020. Patient demographics were recorded. Radiographic analysis of the coronal limb alignment was performed, limb length discrepancy was measured and topography of the exostoses was recorded. We propose a classification of lower legs in 2 groups and 4 types according to the presence and the location of exostoses. In group I, there is an intertibio- fibular exostose with fibular origin at the level of the tibiofibular joints. In type IA, at the level of the distal tibiofibular joint with ascension of the distal fibula; in type IB at the level of the proximal tibiofibular joint with a bracketing effect on the proximal tibia and a lateral slope of the proximal tibial growth plate; the type IC is combining features of both IA and IB. In group II, there is no intertibio-fibular exostose coming from the fibula and no growth abnormality is obvious. A clinically notable lower limb discrepancy (LLD) of ≥2 cm was found in 19% of our patients. Approximately 33% of patients had a knee valgus deformity and 44% had an ankle valgus deformity. The knee valgus deformity was due to fibular growth anomalies and not to distal femur anomalies. The majority of lower legs had fibular growth anomalies (72%) which was a significant risk factor for knee valgus deformity and leg length discrepancy. On the contrary, we found no correlation between number, location and volume of distal femoral exostoses and genu valgum nor leg length discrepancy. Presence of intertibio-fibular exostoses is a risk factor for knee valgus deformity and leg length discrepancy. The presence of these exostoses should lead to a close follow-up of the patient.

Potential influence of factors for genu valgus with hereditary multiple exostoses.

Genu valgus is one of the most common limb deformities in hereditary multiple exostoses (HME). However, it is easily concealed and may account for subsequent osteoarthritis of the knee. The knees of 56 patients (33 men and 23 women) with HME were investigated bilaterally. Knee valgus was described by the mechanical axis deviation (MAD), mechanical lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA). We investigated sex, age, BMI, total number of palpable osteochondromas, number of radiographic osteochondromas around the knee, forearm deformities, morphology and distribution of lesions, and correlations between these factors and genu valgus. The measurement of LDFA and MPTA was performed to identify the sources of genu valgus deformity. Based on the measurement of the mechanical axis, limbs were classified as genu valgus (n = 22) or normal mechanical axis groups (n = 90). The different severities of the genu valgus patients were classified by MAD. By bivariate logistic regression, genu valgus was significantly associated with more sessile and flared metaphyseal lesions. However, only the number of flared metaphyseal lesions had a significant influence on the severity of genu valgus. By analyzing the LDFA and MPTA, it was found that abnormalities of both proximal tibia and distal femur play important roles in genu valgus. Early detection of sessile and flared metaphyseal knee lesions in patients with HME can contribute to early intervention of genu valgus. Level of relevance: Level 2.

Intra-articular acetabular osteochondroma in patients with multiple hereditary exostoses.

We report three additional cases of intra-articular acetabular osteochondroma in multiple hereditary exostoses patients in order to raise the awareness of this rare location, to prompt early diagnosis, and to present various treatment options according to the patient's condition. A 2.5-year-old boy presenting with an out-toeing gait had a large acetabular osteochondroma causing lateral displacement of the femoral head and acetabular dysplasia. Mass excision through hip subluxation via anterior approach and concomitant Dega osteotomy resulted in a congruent, well-developed, and well-covered hip joint at 11-year follow-up. A 10-year-old boy showing a pedunculated osteochondroma arising from the triradiate cartilage was successfully treated by arthroscopic excision. Normal development of the hip joint was observed at skeletal maturity. A 6-year-old boy presented with a painless limp. Acetabular osteochondroma could be confirmed by computed tomography scan, which was excised through hip subluxation by anterior approach. Persistent coxa valga and femoral head uncovering were addressed by femoral varization osteotomy at 9 years of age. A high index of suspicion is required to detect a lesion at this rare location. Various procedures may be considered according to the pathoanatomy. Acetabular dysplasia, coxa valga, and femoroacetabular impingement by femur neck mass, if associated, should be addressed in due time.

Modified osteotomy for treatment of forearm deformities (Masada IIb) in hereditary multiple osteochondromas: a retrospective review.

PURPOSE: Approximately 30% of patients with hereditary multiple osteochondromas (HMO) have forearm deformity and dysfunction. The aim of this retrospective study was to review our experience with the surgical treatment of children with HMO and Masada IIb forearm deformities. METHODS: Data of eight children treated for HMO Masada IIb forearm deformity at our hospital between 2015 and 2019 were collected from the hospital records and retrospectively reviewed. All patients underwent ulnar lengthening by distraction osteogenesis using either the Orthofix or Ilizarov external fixator. Range of movements at the elbow and wrist joints, and forearm supination/pronation, before and after the operation were recorded. Radiographs were evaluated by the Fogel method, and wrist joint function by the Krimmer method. RESULTS: Follow-up radiographs showed significant improvement in relative ulnar shortening after treatment (pre-operative 9.23 ± 5.21 mm; post-operative 0.33 ± 4.13 mm). Changes in radial articular angle (pre-operative 33.55° ± 3.88° to 32.78° ± 6.57°) and carpal slip (pre-operative 45.00% ± 19.09%; post-operative 43.13% ± 16.68%) were not significant. Elbow flexion and extension, wrist flexion and extension, ulnar and radial deviation at wrist, and forearm rotation were significantly improved after surgery. Wrist function was graded as excellent in seven patients and as good in one patient. One patient treated with the Ilizarov external fixator had poor radial head reduction. CONCLUSION: Ulnar lengthening with distraction osteogenesis is an effective treatment for HMO Masada IIb deformities. The optimum site for ulnar osteotomy appears to be at the proximal one-third to one-fourth of the ulna.

Incidental finding of hereditary multiple osteochondroma causing ischiofemoral impingement.

Ischiofemoral impingement (IFI) has been described in the medical literature as a cause of hip pain. IFI occurs due to an abnormal contact or reduced space between the lesser trochanter and the lateral border of the ischium and is an often unrecognised cause of pain and snapping in the hip. Association of multiple exostoses and a skeletal dysplasia characterised by an abnormal modelling of bone metaphysis and osseous deformities is highly characteristic of this disease. Consequently, multiple exostoses may narrow the ischiofemoral space and cause impingement and pain, even in the absence of malignant transformation. Surgical excision of exostosis of the lesser trochanter is a safe and effective method of treatment for patients with IFI. We present a case of left hip pain with incidental finding of hereditary multiple osteochondroma causing IFI and discuss the predisposing factors and review of literature.

Corrective Surgery for a Forearm Deformity in a Middle-Aged Patient with Multiple Hereditary Exostoses: A Case Report.

CASE: A 48-year-old man underwent corrective surgery for a deformity of the left forearm because of multiple hereditary exostoses (MHE). The patient had no complaint of pain, the appearance of his forearm improved, and acceptable range of motion of the wrist and forearm were maintained at 14-month follow-up. CONCLUSION: The esthetic forearm deformity in the middle-aged patient with MHE was successfully improved without sacrificing function. Although there is little evidence of forearm corrective surgeries for adult patients with MHE, this report could expand surgical indications for them.

Natural History and Characteristics of Hand Exostoses in Multiple Hereditary Exostoses.

PURPOSE: Multiple hereditary exostoses (MHEs) comprise a rare skeletal disorder. This study aimed to elucidate the natural history and characteristics of hand exostoses by focusing on their progression or regression and their association with shortening and angular deformation of the finger bones. METHODS: Of 60 MHE patients who presented to our hospital between 2005 and 2019, 32 patients (62 hands) who underwent hand x-ray examinations were included in a study of initial presentation. Among them, 15 patients (30 hands) who underwent consecutive x-ray examinations before epiphyseal closure were included in a subsequent follow-up study (follow-up period, 6.9 years). We investigated the incidence and common location of hand involvement by exostoses during the initial examination study. We further investigated the progression or regression of hand exostoses and the influence of hand exostoses on longitudinal bone growth and the angular deformation of finger bones during the follow-up study. RESULTS: In the initial study, we observed exostoses in 30 (60 hands) of 32 (62 hands) patients. The average number of exostoses per hand was 5.2. Exostoses developed more frequently in the middle and ring proximal phalanges and the fifth metacarpal. In the follow-up study, 3.1 exostoses per hand spontaneously regressed and 2.9 exostoses per hand occurred de novo with growth. Progression of exostoses was mainly observed by approximately age 15 years; thereafter, spontaneous regression became dominant. Regression of exostoses was frequently observed in metacarpals, whereas de novo exostoses frequently occurred in phalangeal bones, particularly in distal phalanges. Growth plate involvement by exostoses did not influence the longitudinal growth of finger bones, but it increased their angulation. CONCLUSIONS: The hand is a common location of exostoses development for MHE patients. Although some exostoses in the hands regress with skeletal maturity, hand involvement by exostoses can result in angular deformity. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

Osteochondromas: An Updated Review of Epidemiology, Pathogenesis, Clinical Presentation, Radiological Features and Treatment Options.

Osteochondroma, the most common benign bone tumor, is a projection on the external surface of the bone, which can be sessile or pedunculated. 85% of osteochondromas present as solitary lesions, while 15% occur in the context of hereditary multiple exostoses (HME), a genetic disorder that is inherited in an autosomal dominant manner. Although often asymptomatic, symptoms may eventuate from compression of adjacent vessels or nerves, fractures, osseous deformities, bursa formation, or malignant transformation. Cartilage cap thickness >2 cm in adults or >3 cm in children as well as new onset of pain or growth, or rapid growth of the lesion, especially after the closure of the growth plate, might reflect cancerous transformation. Surgical resection is indicated for symptomatic lesions, complications, cosmetic reasons or malignant transformation. Excision of the tumor with free margin is the treatment of choice. Local recurrence is less than 2% if complete resection is achieved.

Characteristics of hip impingement syndrome in patients with multiple hereditary exostoses.

BACKGROUNDS: This study aimed to investigate the characteristic deformities of the hip in multiple hereditary exostoses patients (MHE) and its association with the hip impingement syndrome. MATERIALS AND METHODS: Between 2001 and 2019, total 51 patients (102 hips) were evaluated in this study. Patients with MHE were classified to femoro-acetabular impingement (FAI) symptom group, ischio-femoral impingement (IFI) symptom group and non-impingement symptom group by comparing the symptoms, clinical signs and imaging studies. To assess the morphometry of the hip in patients with MHE, the femoral neck-shaft angle, Sharp's acetabular angle and center-edge (CE) angle were evaluated. Alpha angle was further evaluated to investigate the FAI using radiographs, and the minimum ischio-femoral distance was further measured to investigate the IFI using computed-tomographic (CT) study. RESULTS: On hip impingement symptom analysis, FAI symptom and IFI symptom were confirmed in 14 hip joints and 18 hip joints, respectively. Unlike general population, the number of the hip with IFI-symptom was higher than those with FAI symptom in this study. In morphometric evaluation of MHE hips, coxa valga was most prominent deformity with occasional tendency of mild acetabular dysplasia. In a comparison of morphometric study between the impingement symptom group and non-symptom group, the FAI symptom showed significant differences of morphometric measure values than those of the non-symptom group (FAI symptom group vs. Non-FAI symptom group; Femoral neck-shaft angle (153.9 vs 142.6), Sharp's angle (45.0 vs 41.5), CE angle (21.1 vs 28.8) and alpha angle (76.7 vs 57.9)). Similarly, the IFI symptom group also showed significant differences of morphometric measure values than those of the non-symptom group (IFI-symptom vs. Non-IFI symptom; Femoral neck-shaft angle (150.9 vs 142.7), Sharp's angle (44.7 vs 41.4), CE angle (21.1 vs 29.3) and alpha angle (73.3 vs 56.8)). In addition, the minimum ischio-femoral distance measured using CT was significantly decreased in the IFI symptom group (IFI symptom group: 6.6, Non-IFI symptom group: 16.4). CONCLUSION: The results suggest that the characteristic deformities represented by coxa valga in the MHE hip act as an offset for FAI symptoms, on the contrary, act as a trigger for IFI symptoms. LEVEL OF EVIDENCE: Level III.