Proximal Femur Guided Growth: A Systematic Review.

Children with cerebral palsy (CP) and those with avascular necosis (AVN) after treatment of developmental hip dysplasia (DDH) are at risk of developing coxa valga. Proximal femur guided growth is a minimally invasive option to correct this deformity. A systematic review of articles that described treatment of coxa valga with proximal femur guided growth (PFGG) and reporting on primary radiographic outcomes, demographic variables, surgical variables and complications. One hundred and seventy-nine hips underwent PFGG (117 with CP and 62 with lateral overgrowth). Average age at surgery was 8.1 years; average follow-up was 52.5 months. Migration percentage improved from 11.2% (p < 0.0001). Neck-shaft angle improved by 11.9° (p < 0.0001). The most common complication was screw growth out of the physis (30% of cases). PFGG can correct coxa valga, improve radiographic parameters, and in children with CP prevent further subluxation. This technique modulates proximal femur growth, induces changes to the acetabulum and can correct valgus deformity. Evidence Level III. (Journal of Surgical Orthopaedic Advances 32(4):049-052, 2024).

Long-term outcome of total hip arthroplasty in patients with multiple hereditary exostosis.

BACKGROUND: Multiple hereditary exostosis (MHE) is a rare autosomal dominant disorder characterized by multiple osteochondromas. There is a paucity of literature concerning total hip arthroplasty (THA) in patients with MHE. The aim of this study is to report long-term outcomes of THA in patients with MHE. METHODS: Fourteen patients undergoing 15 THA's for the treatment of osteoarthritis in the presence of osteochondromas and proximal femoral deformity secondary to MHE were reviewed. Mean age at the time of surgery and follow-up was 56 and 12 years. Seven (47%) had uncemented femoral components. Eleven hips had coxa valga on preoperative imaging. Clinical outcomes were assessed with both Harris hip scores (HHS) and Musculoskeletal Tumor Society Scores (MSTS). RESULTS: Following surgery, there was an improvement in the HHS (48-82, p < 0.01) and MSTS scores (41-70%, p < 0.01). Complications occurred in 5 patients leading to reoperation in 3 patients, of which 2 patients underwent a revision procedure at 19 and 20-years postoperative. The 10-year revision free survival was 100%. CONCLUSIONS: THA in the setting of MHE reliably improves patient function. One in three patients will have a postoperative complication; however, the long-term incidence of revision is low.

Virtual 3D femur model to assess femoral version: comparison to the 2D axial slice approach.

BACKGROUND: Quantifying femoral version is crucial in diagnosing femoral version abnormalities and for accurate pre-surgical planning. There are numerous methods for measuring femoral version, however, reliability studies for most of these methods excluded children with hip deformities. OBJECTIVE: To propose a method of measuring femoral version based on a virtual 3D femur model, and systematically compare its reliability to the widely used Murphy's 2D axial slice technique. MATERIALS AND METHODS: We searched our imaging database to identify hip/femur CTs performed on children (<18 years old) with a clinical indication of femoral version measurement (September 2021-August 2022). Exclusion criteria were prior hip surgery, and inadequate image quality or field-of-view. Two blinded radiologists independently measured femoral version using the virtual 3D femur model and Murphy's 2D axial slice method. To assess intrareader variability, we randomly selected 20% of the study sample for re-measurements by the two radiologists >2 weeks later. We analyzed the reliability and correlation of these techniques via intraclass correlation coefficient (ICC), Bland-Altman analysis, and deformity subgroup analysis. RESULTS: Our study sample consisted of 142 femurs from 71 patients (10.6±4.4 years, male=31). Intra- and inter-reader correlations for both techniques were excellent (ICC≥0.91). However, Bland-Altman analysis revealed that the standard deviation (SD) of the absolute difference between the two radiologists for the Murphy method (mean 13.7°) was larger than that of the 3D femur model technique (mean 4.8°), indicating higher reader variability. In femurs with hip flexion deformity, the SD of the absolute difference for the Murphy technique was 17°, compared to 6.5° for the 3D femur model technique. In femurs with apparent coxa valga deformity, the SD of the absolute difference for the Murphy technique was 10.4°, compared to 5.2° for the 3D femur model technique. CONCLUSION: The 3D femur model technique is more reliable than the Murphy's 2D axial slice technique in measuring femoral version, especially in children with hip flexion and apparent coxa valga deformities.

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.

Debilitating hip degeneration in trichothiodystrophy: Association with ERCC2/XPD mutations, osteosclerosis, osteopenia, coxa valga, contractures, and osteonecrosis.

Trichothiodystrophy (TTD) is a rare, autosomal recessive, multisystem disorder of DNA repair and transcription with developmental delay and abnormalities in brain, eye, skin, nervous, and musculoskeletal systems. We followed a cohort of 37 patients with TTD at the National Institutes of Health (NIH) from 2001 to 2019 with a median age at last observation of 12 years (range 2-36). Some children with TTD developed rapidly debilitating hip degeneration (DHD): a distinctive pattern of hip pain, inability to walk, and avascular necrosis on imaging. Ten (27%) of the 37 patients had DHD at median age 8 years (range 5-12), followed by onset of imaging findings at median age 9 years (range 5-13). All 10 had mutations in the ERCC2/XPD gene. In 7 of the 10 affected patients, DHD rapidly became bilateral. DHD was associated with coxa valga, central osteosclerosis with peripheral osteopenia of the skeleton, and contractures/tightness of the lower limbs. Except for one patient, surgical interventions were generally not effective at preventing DHD. Four patients with DHD died at a median age of 11 years (range 9-15). TTD patients with ERCC2/XPD gene mutations have a high risk of musculoskeletal abnormalities and DHD leading to poor outcomes. Monitoring by history, physical examination, imaging, and by physical medicine and rehabilitation specialists may be warranted.

The effectiveness of adding guided growth to soft tissue release in treating spastic hip displacement.

BACKGROUND: Guided growth at the proximal femur using one transphyseal screw corrects coxa valga and improves hip displacement in cerebral palsy. This study aimed to validate the effects of adding guided growth (GG) to soft tissue release (STR), in terms of decreasing the migration percentage (MP), compared to those with soft tissue alone. METHODS: This retrospective study comprised patients with cerebral palsy who underwent soft tissue release alone (Group STR) or soft tissue release plus guided growth (Group GG) for hip displacement (mean age, 8.1 years; mean follow-up, 4.9 years). Difference in the MP and rate of controlling MP <40% at 2 years postoperatively and rate of revision surgeries at 5 years postoperatively were compared between the groups. RESULTS: The two groups were comparable in age, side, and gross motor function level, but Group GG (n = 24) had more severe hip displacement preoperatively than did Group STR (n = 64). Group GG had a significantly greater 2-year decrease in the MP (-14.8% vs. -11.8%, p < 0.05) than did Group STR. Among patients with a pre-operative MP >50%, the rate of MP <40% was greater in Group GG (73%) than in Group STR (41%). Revision surgeries, mainly repeated guided growth and soft tissue release, were comparable between the groups. CONCLUSIONS: This is the first comparative study to support adding guided growth to soft tissue release, as it results in greater improvements in hip displacement than that with soft tissue release alone. Non-ambulatory patients or severe hip displacement with MP 50%-70% could benefit from this less aggressive surgery by controlling the MP under 40% without femoral osteotomy.

Multivariate analysis of the relationship between gluteal muscle contracture and coxa valga.

BACKGROUND: Gluteal muscle contracture (GMC) is a disease characterized by the limited function of the hip joint, knee pain, and abnormal gait. There is a lack of research on the effect of GMC on the hip joint structure to date. This study aims to analyze the association between GMC and the deformity of the hip and pelvis. METHODS: Standing anteroposterior pelvic radiographs of 214 patients (152 with gluteal muscle contracture and 62 without gluteal muscle contracture) were retrospectively collected. Neck-shaft angle, lateral center edge angle, Tönnis angle, femoral head coverage index, acetabular depth, Sacro-femoral-pubic angle, and obturator foramen ratio were respectively measured and included in the following statistical analysis. The collected data were analyzed using logistical regression and multiple linear regression to explore the factors influencing coxa valga and SFP angle. RESULTS: GMC was identified as a common factor significantly associated with coxa valga and increased SFP angle. There is a difference of risk factors in logistic regression for coxa valga between the left and right sides. CONCLUSION: GMC is a significant risk factor for coxa valga and increased SFP angle. Given that GMC can cause coxa valga and likely alter the pelvis's position, GMC should be paid attention to and treated early.

Modular stem in total hip arthroplasty for patients with trochanter valgus deformity: surgical technique and case series.

BACKGROUND: Trochanter valgus deformity (TVD) is a rare condition of total hip arthroplasty (THA). Femoral osteotomy could be required in correcting the deformity to implant femoral stem in severe TVD. In this study, we described one unpublished technique of reverse sleeve of S-ROM to get through the complex situation. This study aimed to summarize and evaluate its technical challenges, safety and effectiveness. METHODS: From January 2006 to December 2014, we enrolled patients whose sleeves were implanted towards the great trochanter in THA with TVD. Their demographics, perioperative and postoperative information were recorded. To explore its indication, we measured and analyzed the ratio of greater trochanter/lesser trochanter (G/L ratio) and trochanter valgus angle (TVA). RESULTS: Twelve patients (1 male and 11 female, average age 42.30 ± 10.23) had mean follow-up of 6 years. Among them, only two patients had intraoperative femoral fracture. The survivorship of femoral prosthesis was 100%. The Harris hip score (HHS) increased from preoperative 34.31 ± 14.43 to postoperative 84.12 ± 11.33. All patients' G/L ratio were larger than 1.50. CONCLUSIONS: The reverse sleeve of S-ROM was a reliable method for the patients with severe TVD, which brought satisfying clinical outcomes in mid-term follow-up.

Guided Growth Improves Coxa Valga and Hip Subluxation in Children with Cerebral Palsy.

BACKGROUND: Spastic hip subluxation or dislocation that is associated with an excessive coxa valga deformity is a common pathologic condition in children with cerebral palsy (CP) that is often treated with large bone reconstructive procedures. Guided growth techniques (such as stapling, plate, or transphyseal screw) have been widely used to alter the growth axis in patients with a lower-limb deformity but only a few reports have described their use in patients with coxa valga deformities. QUESTIONS/PURPOSES: (1) Does guided growth surgery using a transphyseal screw combined with adductor tenotomy prevent progressive coxa valga deformity and lateral hip subluxation in children with CP? (2) What factors influence the correction of coxa valga deformity and the success of hip stabilization? (3) What complications were associated with this operation and how often did children treated with it undergo reoperation? METHODS: From 2012 to 2016, at our institution, three authors (H-CH, KNK, K-WW) retrospectively studied data on children with CP who underwent guided growth of the hip for progressive bilateral hip subluxation associated with coxa valga deformities. A single percutaneous screw was inserted across the inferomedial portion of proximal femoral physis in an AP view and centered along femoral neck in lateral view under fluoroscopy guidance. During the period, we treated 25 consecutive children with CP who had progressive hip subluxation with coxa valga deformities. The indications for surgery were migration percentage > 30% and head-shaft angle > 155° with at least 2 years growth remaining. Of those, 13 patients underwent guided growth alone, and 48% (12) underwent a combination of guided growth and adductor tenotomy. Of the 25 patients treated with this approach, 96% (24) were available for follow-up with complete data at a minimum of 2 years follow-up (mean 50 months; range 25 to 72). All children (17 boys and seven girls; 48 hips) underwent surgery at a mean age of 8 years (range 5 to 12). With regard to the gross motor function classification system, three patients were Level 1, four patients were Level II, seven patients were Level III, seven were Level IV, and three were Level V. Radiographic parameters including the head-shaft angle, Hilgenreiner's epiphyseal angle, acetabular index, and Reimer's migration percentage were assessed before surgery and at the latest follow-up examination by one author (H-CH). Complications and reoperations were assessed by chart review. During the period in question, we generally offered secondary reconstructive surgery to patients who underwent a guided growth procedure once their subluxation progressed. RESULTS: With the data available, the coxa valga and lateral hip subluxation improved in terms of the reduction of head-shaft angle by a mean of 13° ± 7° (95% CI 11 to 15; p < 0.001) and the reduction of the migration percentage by 10% ± 11% (95% CI 7 to 13; p < 0.001). After controlling for potentially confounding variables like gender, gross motor function classification system, Hilgenreiner's epiphyseal angle and acetabular index, we found that longer follow-up duration (r = 0.234; p < 0.001) and a smaller preoperative migration percentage (r = -0.258; p = 0.004) were associated with larger changes in the head-shaft angle. In terms of complications, we found that the proximal femoral physis grew off the screw tip in 44% (21 of 48 hips) at a mean of 28 months. Among these, 31% of hips (15 of 48) in 33% of patients (eight of 24) underwent replacement with a longer screw. Among the 17% of hips (eight of 48) in 21% of patients (five of 24) who had progressive lateral subluxation and underwent secondary reconstructive surgery, we found that their preoperative acetabular index was higher (mean 29° versus 21°; p < 0.001), as was their head-shaft angle (mean 166° versus 162°; p = 0.045), and migration percentage (mean 54% versus 36 %; p < 0.001). CONCLUSIONS: Although guided growth with single transphyseal screw did not create as large a degree of varus as proximal femoral osteotomy, it did stabilize the hip in children with cerebral palsy with migration percentage less than 50% in our series. It is a simple procedure that can be of benefit to children with cerebral palsy with unstable hip. Reoperation in patients where the physis has grown off the screw tip can be a problem; fortunately, it is a rather minor procedure to replace with a longer screw. LEVEL OF EVIDENCE: Level III, therapeutic study.

Finite element analysis of mechanical behavior of human dysplastic hip joints: a systematic review.

Developmental dysplasia of the hip (DDH) is a common condition predisposing to osteoarthritis (OA). Especially since DDH is best identified and treated in infancy before bones ossify, there is surprisingly a near-complete absence of literature examining mechanical behavior of infant dysplastic hips. We sought to identify current practice in finite element modeling (FEM) of DDH, to inform future modeling of infant dysplastic hips. We performed multi-database systematic review using PRISMA criteria. Abstracts (n = 126) fulfilling inclusion criteria were screened for methodological quality, and results were analyzed and summarized for eligible articles (n = 12). The majority of the studies modeled human adult dysplastic hips. Two studies focused on etiology of DDH through simulating mechanobiological growth of prenatal hips; we found no FEM-based studies in infants or children. Finite element models used either patient-specific geometry or idealized average geometry. Diversities in choice of material properties, boundary conditions, and loading scenarios were found in the finite-element models. FEM of adult dysplastic hips demonstrated generally smaller cartilage contact area in dysplastic hips than in normal joints. Contact pressure (CP) may be higher or lower in dysplastic hips depending on joint geometry and mechanical contribution of labrum (Lb). FEM of mechanobiological growth of prenatal hip joints revealed evidence for effects of the joint mechanical environment on formation of coxa valga, asymmetrically shallow acetabulum and malformed femoral head associated with DDH. Future modeling informed by the results of this review may yield valuable insights into optimal treatment of DDH, and into how and why OA develops early in DDH.

Outcome of extensive varus and valgus stem alignment in short-stem THA: clinical and radiological analysis using EBRA-FCA.

INTRODUCTION: The principle of implanting a calcar-guided short stem consists of an individual alignment alongside the medial calcar providing the ability of reconstructing varus and valgus anatomy in a great variety. However, still, there are broad concerns about the safety of extensive varus and valgus positioning in regard to stability, bony alterations, and periprosthetic fractures. MATERIALS AND METHODS: 216 total hip arthroplasties using a calcar-guided short stem (optimys, Mathys Ltd.) in 162 patients were included. Depending on postoperative CCD angle, hips were divided into five groups (A-E). Varus- and valgus tilt and axial subsidence were assessed by "Einzel-Bild-Roentgen-Analyse"(EBRA-FCA, femoral component analysis) over a 2-year follow-up. The incidence of stress-shielding and cortical hypertrophy as well as clinical outcome [Harris Hip Score (HHS)] were reported. RESULTS: Postoperative CCD angles ranged from 117.9° to 145.6° and mean postoperative CCD angles in group A-E were 123.3°, 128.0°, 132.4°, 137.5°, and 142.5°, respectively. After 2 years, the mean varus/valgus tilt was -0.16°, 0.37°, 0.48°, 0.01°, and 0.86°, respectively (p = 0.502). Axial subsidence after 2 years was 1.20, 1.02, 1.44, 1.50, and 2.62 mm, respectively (p = 0.043). No periprosthetic fractures occurred and none of the stems had to be revised. Rates of stress-shielding and cortical hypertrophy as well as HHS showed no significant difference between the groups. CONCLUSIONS: Valgus alignment results in increased subsidence but does not affect the clinical outcome. There is no difference in stress shielding and cortical hypertrophy between the groups. The authors recommend long term monitoring of valgus aligned stems.

Preoperative digital planning versus postoperative outcomes in total hip arthroplasty using a calcar-guided short stem: frequent valgization can be avoided.

INTRODUCTION: Modern total hip arthroplasty is largely dependent on the successful preservation of hip geometry. Thus, a successful implementation of the preoperative planning is of great importance. The present study evaluates the accuracy of anatomic hip reconstruction predicted by 2D digital planning using a calcar-guided short stem of the newest generation. METHODS: A calcar-guided short stem was implanted in 109 patients in combination with a cementless cup using the modified anterolateral approach. Preoperative digital planning was performed including implant size, caput-collum-diaphyseal angle, offset, and leg length using mediCAD II software. A coordinate system and individual scale factors were implemented. Postoperative outcome was evaluated accordingly and was compared to the planning. RESULTS: Intraoperatively used stem sizes were within one unit of the planned stem sizes. The postoperative stem alignment showed a minor and insignificant (p = 0.159) mean valgization of 0.5° (SD 3.79°) compared to the planned caput-collum-diaphyseal angles. Compared to the planning, mean femoral offset gained 2.18 (SD 4.24) mm, while acetabular offset was reduced by 0.78 (SD 4.36) mm during implantation resulting in an increased global offset of 1.40 (SD 5.51) mm (p = 0.0094). Postoperative femoroacetabular height increased by a mean of 5.00 (SD 5.98) mm (p < 0.0001) compared to preoperative measures. DISCUSSION: Two-dimensional digital preoperative planning in calcar-guided short-stem total hip arthroplasty assures a satisfying implementation of the intended anatomy. Valgization, which has been frequently observed in previous short-stem designs, negatively affecting offset, can be avoided. However, surgeons have to be aware of a possible leg lengthening.

Is there an Increase in Valgus Deviation in Tibial Distraction Using the Lengthening Over Nail Technique?

BACKGROUND: During tibial lengthening, the soft tissues of the posterolateral compartment produce distraction-resisting forces causing valgus angulation. Although this occurs with the classic Ilizarov method, whether a valgus deformity develops with the lengthening over nail (LON) technique is questioned, because the intramedullary nail is thought to resist deforming forces and adequately maintain alignment of the distracted bone. QUESTIONS/PURPOSES: The purposes of this study were to (1) determine the amount of valgus deviation during tibial lengthening with the LON technique; and (2) analyze the factors that may be associated with valgus deviation with the LON technique. METHODS: Between June 2009 and September 2013, we performed 346 tibial lengthenings using the LON technique, lengthening and then nail technique, or lengthening with an intramedullary lengthening device. Sixty patients (120 tibias) who underwent bilateral lower leg lengthening with the LON technique were enrolled in this retrospective study. To limit the number of variables, we analyzed only the right tibia in all patients (60 tibias). The mean followup was 42 months (range, 26-71 months). The mean age of the patients was 25 years (range, 18-40 years). There were 36 male and 24 female patients. The mean final length gain was 67 ± 9 mm. The mean time for distraction was 100 ± 25 days. The overall valgus deviation was assessed by measuring the change in the medial proximal tibial angle and mechanical femorotibial angle on radiographs obtained before and after surgery and after completion of lengthening. Several demographic, surgical, and distraction-related variables were considered possible factors to prevent valgus deviation: proximal fixation method; presence of a blocking screw; diameter and length of the intramedullary nail; degree of nail insertion; length of the nail in the distal segment after completion of distraction; final length gain; and patient's BMI. During the period studied, the blocking screw was to maintain the mechanical axis in patients who had neutral or valgus alignment preoperatively, or to prevent more valgus change in patients who underwent acute correction of varus deformity intraoperatively. Uni- and multivariate analyses were conducted. RESULTS: Valgus deviation occurred during the tibial LON. The medial proximal tibial angle increased from 86° (95% CI, 85°-86°) to 90° (95% CI, 89°-91°) (p < 0.001). The mechanical femorotibial angle changed from 2.2° varus (95% CI, 3°-1.4° varus) to 2.6° valgus (95% CI, 1.8°-3.4° valgus) (p < 0.001). Valgus deviation was evident in proximal and distal segments. In the multivariate regression model, use of a blocking screw was the only factor that was associated with decreased valgus deviation, and its effect size, although detectable, was small (-2.62; 95% CI, -4.65 to -0.59; p = 0.013). CONCLUSIONS: We found that valgus deviation does occur during tibial lengthening using the LON technique, but that blocking screw placement may help to minimize the likelihood that severe valgus deviation will occur. Future prospective studies should be conducted to confirm this preliminary finding. LEVEL OF EVIDENCE: Level III, therapeutic study.

Guided Growth of the Proximal Femur for Hip Displacement in Children With Cerebral Palsy.

BACKGROUND: Guided growth by 1 eccentric transphyseal screw has been used to correct lower limb deformities. Pilot animal studies showed encouraging results in producing varus deformity in the proximal femur. The purpose of this study was to report the preliminary results of guided growth surgery to treat spastic hip displacement. METHODS: This case series study included consecutive patients who received soft-tissue release and guided growth at the proximal femur from January 2004 to May 2012 with minimal 2-year follow-up. Surgical indications were children with spastic cerebral palsy aged 4 to 10 years, a gross motor function classification system level IV or V, and hip displacement on 1 or both sides. Study outcomes were Reimer's migration percentage (MP) and the head-shaft angle (HSA). RESULTS: Nine children with 13 spastic displaced hips received surgery at the age of 6.2 years and were followed up for a mean of 45.6 months. The mean MP improved significantly from 52.2% preoperatively to 45.8% at 3 months, 40.3% at 1 year, and 37.1% at 2 years after operation. HSA was unchanged in the first 3 months, and deceased from 173.3 to 166.4 degrees at 1 year (P<0.01) and to 162.7 degrees at 2 years postoperatively. The screw was usually backed out from the femoral epiphysis in the second postoperative year, and no radiologic bony bar or other surgical complications occurred. CONCLUSIONS: The immediate postoperative improvement of MP was the result of soft-tissue release. From postoperative 3 months to 2 years, the HSA was reduced by 10.6 degrees and the MP further improved by 8.7%. Less surgical dissection, faster recovery of motion, and less comorbidity than varus osteotomy make guided growth surgery a treatment option for coxa valga in spastic hip displacement in nonambulant cerebral palsy children. LEVEL OF EVIDENCE: Level IV-therapeutic, case series.

Is hip dysplasia a common deformity in skeletally mature patients with hereditary multiple exostoses?

BACKGROUND: Various deformities appear in hereditary multiple exostoses (HMEs). Deformities around the knee or ankle joints are easy to detect in this disease because such deformities are visible in appearance. However, deformities in the hip joints of skeletally mature patients are not well understood because their tumors are invisible. METHODS: To understand deformities around the hip joint in HMEs, we investigated 36 hip joints in 19 skeletally mature patients (12 males, 7 females). The mean age at last X-ray imaging investigation was 29.2 years (14.5-66.5 years). We evaluated the lesions of exostoses around the acetabulum and proximal femur, Wiberg's center-edge angle (CEA), neck-shaft angle (NSA), acetabular depth-width ratio (ADR), and Sharp's acetabular angle. RESULTS: No exostoses were present in four hips of three cases. Thirty-one hip joints had exostoses on the medial side of the femoral neck. Exostoses existed on the lateral side of the femoral neck in 16 hips. None of the patients had acetabuluar tumors. One patient experienced pain because of impingement between the acetabular rim and medial tumors of the femoral neck. The increase in NSA, which is an index of proximal femoral deformity, was common with a mean NSA of 147.3 °. Two indices of acetabular deformity, Sharp's angle and ADR, were within normal limits with a mean Sharp's angle of 41.3 ° and mean ADR of 269. The average CEA was 29.9 °. CONCLUSIONS: Hip dysplasia is not necessarily common in skeletally mature patients with HMEs. To determine the possibility of hip dysplasia in skeletally immature patients with HMEs, ADR may be a useful reference index.

Determinants of Hip Displacement in Children With Cerebral Palsy.

BACKGROUND: Coxa valga and femoral anteversion often are seen in patients with spastic hip displacement and osteotomy is recommended. However, the relationship between femoral deformities and hip displacement has not been clearly defined and other factors, such as joint motion and posture, should be considered before recommending treatment. QUESTIONS: For children with cerebral palsy with Gross Motor Function Classification System Level IV or V, we questioned (1) whether hip abduction range correlates with hip displacement, (2) what the relationships are between proximal femoral deformities and hip displacement, and (3) whether the patient with a windblown posture has greater degrees of femoral anteversion? METHODS: We retrospectively studied 31 consecutive children with cerebral palsy with Level IV or V gross motor function who underwent three-dimensional CT for preoperative assessment of hip displacement between January 2010 and December 2013. Among the children, 23 had a windblown posture and eight had symmetric hip motion. Femoral anteversion and true neck-shaft angle were measured from the three-dimensional CT images. Migration percentage was the dependent variable we chose to study in relation to femoral anteversion, neck-shaft angle, maximal hip abduction, and hip flexion contracture, using correlations and multiple linear regressions. Using ANOVA and Scheffé's post hoc tests, we analyzed and compared the data of 23 abducted hips and 23 adducted hips in the 23 children with windblown posture and in 16 displaced hips in the eight children with symmetric hip abduction. RESULTS: Greater migration percentage was associated with less hip abduction range (r = -0.86; p < 0.001). Femoral anteversion had a weak correlation (r = 0.28; p < 0.05) to migration percentage, and the association became insignificant after considering hip abduction motion. Adducted windblown hips had greater femoral anteversion than the symmetric displaced hips and abducted windblown hips (46° vs 36° and 38°, respectively; p < 0.05). CONCLUSIONS: Our study results did not support a relationship between femoral deformities and hip displacement after considering gross motor function and hip abduction motion. Greater femoral anteversion was noted in the adducted hips of patients with windblown posture, and derotation osteotomy is especially recommended. LEVEL OF EVIDENCE: Level III, diagnostic study.

Developmental pattern of the hip in patients with hereditary multiple exostoses.

BACKGROUND: Coxa valga is a common clinical feature of hereditary multiple exostoses (HME). The current study aimed to determine the unique developmental pattern of the hip in patients with HME and evaluate the factors that influence its progression. METHODS: Thirty patients (57 hips) with HME were divided into two groups according to the Hilgenreiner epiphyseal angle (HEA). Twenty-two patients (44 hips) including 13 men and 9 women were assigned to group 1 (HEA <25°), and 8 patients (13 hips) including 3 men and 5 women were assigned to group 2 (HEA ≥25°). The mean age at the initial presentation was 6.0 (4-12) years with 6.8 (4-11) years of follow-up in group 1, and 10.4 (8-13) years with 5.4 (2-9) years of follow-up in group 2. We measured the HEA, neck-shaft angle (NSA), acetabular index (AI), center-edge angle (CEA), and migration percentage (MP) for radiographic evaluation. RESULTS: Among the hips, 50 (87.7%) hips had coxa valga and 27 (47.4%) hips had abnormal MP (42.1% were borderline and 5.3% were subluxated). There was a significant difference in the HEA and NSA between the groups (p < 0.001 and p < 0.05, respectively). The HEA significantly correlated with the development of the NSA and no correlation was found between the HEA and AI, CEA, and MP. CONCLUSIONS: There was a significant relationship between the HEA at the initial presentation and the NSA at skeletal maturity. We should consider guided growth for patients with lower HEA to prevent significant coxa valga deformity with close follow-up.

Is coxa valga a predictor for the severity of knee osteoarthritis? A cross-sectional study.

PURPOSE: In the present study, we aimed to evaluate the affect of the variations in hip anatomy and pelvic geometry on the severity of knee OA. METHODS: Idiopathic knee OA patients fulfilling the clinical criteria of American College of Rheumatology for OA were enrolled in the study. Several measurements regarding the hip and pelvis were performed on pelvic radiographs. Each knee was graded according to the Kellgren and Lawrence (KL) radiographic system (0-4) along with a categorization in accordance with the medial tibiofemoral joint space widths (JSW). RESULTS: The study group consisted of 111 subjects. The inner and outer pelvic diameters were getting wider as the JSW grade increased. Likewise, among the hip measurements, femoral head, neck and shaft diameters and hip axis lengths were linked with KL grade. There were significant differences in neck-shaft angle (NSA) between groups of JSW with a highest NSA in JSW grade 3. The optimal cut-off value for NSA in predicting the severity of knee OA was 134.4°. Furthermore, NSA beyond 134.4° was found to increase the risk of severe knee OA eightfold. CONCLUSIONS: Variations in pelvic geometry and hip anatomy are associated with the severity of knee OA. People with NSA of above 134.4° have eightfold increased risk of developing severe knee OA. Pelvic radiographies could be evaluated at younger ages-particularly in people with high genetic predispositions-to identify the individuals at high risk and in turn, to tailor the preventive measures to these subjects.

Hip dysplasia is more severe in Charcot-Marie-Tooth disease than in developmental dysplasia of the hip.

BACKGROUND: Patients with Charcot-Marie-Tooth disease may develop hip dysplasia. Hip geometry in these patients has not been well described in the literature. QUESTIONS/PURPOSES: We compared the hip morphometry in Charcot-Marie-Tooth hip dysplasia (CMTHD) and developmental dysplasia of the hip (DDH) in terms of extent of (1) acetabular dysplasia and subluxation, (2) acetabular anteversion and osseous support, (3) coxa valga and femoral version, and (4) osteoarthritis. METHODS: Fourteen patients with CMTHD (19 hips; mean age, 23 years) presenting for periacetabular osteotomy were matched to 45 patients with DDH (45 hips; mean age, 21 years) based on age, sex, and BMI. We assessed acetabular dysplasia and subluxation using lateral center-edge angle (LCEA), anterior center-edge angle (ACEA), and acetabular roof angle of Tönnis (TA) on plain pelvic radiographs and acetabular volume, area of femoral head covered by acetabulum, and percentage of femoral head covered by acetabulum on three-dimensional CT reconstruction models. Acetabular version and bony support, femoral version, and neck-shaft angle were measured on two-dimensional axial CT scans. Hip osteoarthritis was graded radiographically according to Tönnis criteria. RESULTS: Acetabular dysplasia was more severe in CMTHD, as measured by smaller LCEA (p < 0.001), ACEA (p < 0.001), and acetabular volume (p = 0.0178) and larger TA (p = 0.025). Hip subluxation was more pronounced in CMTHD, as demonstrated by lower area of femoral head covered by acetabulum (p = 0.034) and percentage of femoral head covered by acetabulum (p = 0.007). CMTHD was associated with higher acetabular anteversion (p < 0.001), lower anterior (p < 0.001) and posterior (p = 0.072) osseous support, and more severe coxa valga (p < 0.001). More (p = 0.006) arthritic hips were found in CMTHD. CONCLUSIONS: The extent of acetabular dysplasia, hip subluxation, acetabular anteversion, coxa valga, and hip osteoarthritis was more severe in CMTHD. These findings are important in choosing the appropriate surgical strategy for patients affected by CMTHD.