Ligamentum Teres Transfer During Medial Open Reduction in Patients with Developmental Dysplasia of the Hip.

BACKGROUND: The ligamentum teres (LT) is believed to have a number of functions, including a role in hip stability, nociception, proprioception, vascular supply to the femoral head, and synovial fluid circulation. The LT is often excised in the process of performing a medial open reduction (MOR) of the hip. We sought to conduct a retrospective review of hips undergoing a MOR for dislocated infantile developmental dysplasia of the hip (DDH) to compare clinical and radiographic outcomes for patients with and without LT reconstruction. METHODS: We performed a retrospective review of 38 hips treated with MOR with or without LT reconstruction with minimum two-year follow-up. Radiographic outcomes were determined using the Severin score. Information regarding avascular necrosis (AVN), concomitant surgical procedures, repeat dislocation, subsequent surgery, limp, pain, and range of motion symmetry was recorded. RESULTS: Eighteen hips that underwent MOR with LT reconstruction were compared to 20 hips that underwent MOR without LT reconstruction. Mean follow up for this cohort was 70.1 months (median: 61.8; Range: 24.2 to 182.2 months). The group with LT reconstruction had an 11% rate of AVN, the group without LT reconstruction had a 15% rate of AVN (p=1.0) No hips in either group re-dislocated or had pain at final follow up. Two hips (5%) had a limp at most recent follow up, all were in the group that did not receive a LT reconstruction (p=0.488). Three hips (17%) in the LT reconstruction group and one hip (5%) in the other group had asymmetrical hip range of motion at final follow up (p=0.328). CONCLUSION: This study offers preliminary data to suggest that ligamentum teres reconstruction is a safe procedure that can minimize the risk for subluxation or re-dislocation that can occur within the post reduction hip spica cast. Although in this study, the patients who did not have LT reconstruction had a similar re-dislocation rate, we believe that ligamentum teres preservation is a useful adjunct to medial open reduction, especially in centers that may only treat occasional cases or have less experience in applying an excellent hip spica cast.Level of Evidence: III.

Ankle Ganglion Associated with Tarsal Coalition: A Case Report with a 5-Year Follow-up.

CASE: Talocalcaneal coalition (TCC) is a common type of coalition, often neglected. This case is of a 10-year-old girl with a painful ankle mass, diagnosed with TCC and a ganglion cyst. Examination revealed stiff subtalar motion, a submalleolar prominence, and well-circumscribed, tender mass at the posteromedial ankle. Treatment options include short period of casting/observation, excision vs. aspiration of the cyst, resection of the TC coalition, or a combination of the above. She underwent TCC resection with cyst aspiration. CONCLUSION: At the 5-year follow-up, the patient's examination and imaging revealed normal motion without cyst recurrence, indicating resolution of the cyst with coalition resection.

Unsuspected tarsal coalitions in equinus and varus foot deformities.

Tarsal coalitions have been reported in the setting of equinovarus foot deformities, but only as rare isolated findings. Failure to recognize this diagnosis may inhibit successful equinovarus correction. Here, we review a series of tarsal coalitions seen in congenital and neuropathic equinovarus deformity at two institutions, to report the breakdown of types of coalitions encountered, and to suggest methodology to facilitate earlier diagnosis. The records of all patients treated by two of the authors for bilateral equinovarus deformities and found to have either a unilateral or bilateral tarsal coalition between 2006 and 2016 were reviewed. Nine feet with tarsal coalition (calcaneonavicular n = 7 and talocalcaneal n = 2) were reviewed. Five of these cases occurred in patients with idiopathic equinovarus and four cases in patients with equinovarus related to a neurologic disease. All patients were definitively diagnosed by computed tomography scans with 3D reconstruction. In 56% of cases, the patient had previously undergone at least one open procedure before the coalition was recognized. The mean age at diagnosis of the coalition was 11.4 years. Our experience suggests that tarsal coalitions, particularly calcaneonavicular coalitions, may occur more frequently in equinovarus deformities than previously reported. Upon recognition and removal of these coalitions, we were able to achieve improved correction of the equinovarus deformities and improved range of motion. We recommend that surgeons maintain an awareness of this potential concomitant problem in all equinovarus foot deformities and consider advanced imaging in cases which fail to respond to traditional treatment.

Nonossifying Fibromas: A Computed Tomography-based Criteria to Predict Fracture Risk.

BACKGROUND: Nonossifying fibroma (NOF) is the most common benign osseous lesion in children; however, our understanding of which lesions progress to a fracture remains unclear. In this study, we seek to formulate a classification system for NOFs to assess for fracture risk and determine what this classification system tells us regarding fracture risk of the distal tibia and distal femur NOFs. METHODS: Charts were retrospectively reviewed for patients with NOFs. A 4-point criteria was created and used to calculate fracture risk for distal tibia and distal femur NOFs. The analysis included incidence, specificity, and sensitivity. RESULTS: One point was given for each of the following findings on computed tomography (CT) scan: (1) >50% width on coronal view; (2) >50% width on sagittal view; (3) any cortical breach; (4) lack of a neocortex. In total, 34 patients with NOFs of the distal tibia had CT scans, of which 14 fractured. Zero with a 0- or 1-point score fractured, 2 with a 2-point score fractured (20%), 4 with a 3-point score fractured (44%), and 8 with a 4-point score fractured (100%). Sensitivities of 1-, 2-, 3-, and 4-point scores were 100%, 100%, 85.7%, and 57.1%, respectively, and specificities were 71.4%, 71.4%, 80%, and 100%, respectively. A total of 41 patients with NOFs of the distal femur had CT scans, of which 5 fractured. Zero with a 0-point score fractured, 1 with a 1-point score fractured (4%), 0 with a 2-point score fractured, 1 with a 3-point score fractured (20%), and 3 with a 4-point score fractured (100%). Sensitivities of 1-, 2-, 3-, and 4-point scores were 100%, 80%, 80%, and 60%, respectively; and specificities were 60%, 87.8%, 90%, and 100%, respectively. CONCLUSIONS: Our 4-point CT criteria is easy to apply and identifies patients at high risk of fracture, helping surgeons make decisions regarding treatment. LEVEL OF EVIDENCE: Level IV-prognostic study.

Scurvy Findings in a Child with Jacobsen Syndrome: A Case Report.

CASE: We describe the first reported case of scurvy developing secondary to behavioral traits of Jacobsen syndrome. The diagnosis of scurvy was significantly delayed because bleeding symptoms were initially attributed to baseline thrombocytopenia and platelet dysfunction associated with Jacobsen syndrome and patient's medication. Following vitamin C supplementation, signs and symptoms of the patient's disease quickly resolved. CONCLUSIONS: We aim to reinforce the need to consider nutritional deficiencies in patients with complex medical histories and behavioral issues, especially when presenting with new complaints.

The "Double Medial Malleolus": A New Physical Finding in Talocalcaneal Coalition.

PURPOSE: It has been the observation of the senior author that there is a bony fullness or "double medial malleolus" over the middle facet as a consistent finding with most talocalcaneal coalitions (TCC). To document this observation, we reviewed records and radiographs in 3 patient groups. METHODS: Part 1: retrospective chart review was completed for 111 feet to determine the clinical presence of a palpable "double medial malleolus." Part 2: computed tomography (CT) scans for evaluation of tarsal coalition or symptomatic flatfoot between January 2006 and December 2014 were retrospectively reviewed for the same cohort. Soft tissue thickness was measured as the shortest distance between bone and skin surface at both the medial malleolus and the middle facet/coalition. The volume of the middle facet or coalition was measured at their midpoint. These findings were compared among feet with TCC (n=53), calcaneonavicular coalition (CNC) (n=20), and flatfoot (n=38). RESULTS: Part 1-clinical: from medical records, 38 feet (34%) had documented record of a palpable medial prominence. Of the feet reviewed with a "double medial malleolus," all had TCC (no false positives or false negatives). Clinical and CT prominence demonstrated significant correlation (rs=0.519, P=0.001). Part 2-radiographic: CT observation of "double medial malleolus" is significantly associated with TCC (P<0.001). CT observation of double medial malleolus is 81% sensitive and 79% specific as a predictive test for TCC. The middle facet-to-skin distance was significantly closer in those with TCC versus controls (P<0.001). The ratio was larger in patients with TCC versus CNC (P=0.006) or flatfeet (P<0.001). Volume was nearly twice the size in patients with TCC versus the controls (P<0.001). CONCLUSIONS: TCCs have a bony prominence below the medial malleolus on clinical exam and CT scan not present in flatfeet or CNCs. This abnormal middle facet is almost twice the size of the normal middle facet. Obesity or severe valgus may mask this finding. If a palpable bony prominence is noted just below the medial malleolus during examination of a painful foot with a decrease in subtalar motion, the likely diagnosis is TCC. With this added clinical finding, appropriate images can be ordered to confirm the diagnosis of the latter. We advise CT scans with 3D images for surgical planning. The primary finding for tarsal coalitions in textbooks is decreased subtalar motion. This new finding of a palpable enlarged medial prominence just below the medial malleolus is highly associated with TCCs. LEVEL OF EVIDENCE: Level III.

Femoral Neck Aspiration Aids in the Diagnosis of Osteomyelitis In Children With Septic Hip.

BACKGROUND: The role of femoral aspiration (FA) in the treatment of septic arthritis of the hip is controversial. The purpose of this study was to determine if FA conducted concomitantly with irrigation and debridement (I&D) of the septic hip aids in microorganism and osteomyelitis identification and alters the treatment plan, or if the risks of the procedure outweigh its potential benefit. We also compare preoperative magnetic resonance imaging (MRI) with FA for diagnosis of osteomyelitis cooccurring with septic arthritis. METHODS: Retrospective review was performed of all patients treated at a single institution between January 2003 and June 2014 for suspected septic hip arthritis. Eighty-three patients were identified with suspected or confirmed septic arthritis and 28 patients (33%) had cooccurring osteomyelitis. Demographic and clinical data were recorded for each patient. The sensitivity and specificity of FA and MRI for diagnosing osteomyelitis were determined. RESULTS: Among the 83 patients with confirmed or suspected septic arthritis, 31 patients (37%) had a FA performed at the time of the hip I&D, resulting in positive cultures in 17 patients. All of these patients had other positive cultures (blood and/or joint fluid) that grew the same organism. 54 patients (65%) had a preoperative MRI. The MRI was falsely negative in 10 patients, 6 of whom had a positive FA resulting in appropriate management of osteomyelitis. Missed or delayed diagnosis of osteomyelitis resulted in significant morbidity in 3 patients (avascular necrosis and femoral neck fracture, extensive lower extremity osteomyelitis, and subtrochanteric fracture with malunion). No complications associated with FA were identified. FA and MRI were found to have sensitivity/specificity for osteomyelitis of 100%/100% and 38%/95%, respectively. CONCLUSIONS: Although FA did not improve microorganism identification, it did aid in the diagnosis of cooccurring osteomyelitis when treating children with septic arthritis, especially in patients with false negative MRI findings for osteomyelitis. We recommend FA at the time of septic hip I&D as its benefits appear to far outweigh its risks. LEVEL OF EVIDENCE: Level III-diagnostic study.

Single Stem Cell Imaging and Analysis Reveals Telomere Length Differences in Diseased Human and Mouse Skeletal Muscles.

Muscle stem cells (MuSCs) contribute to muscle regeneration following injury. In many muscle disorders, the repeated cycles of damage and repair lead to stem cell dysfunction. While telomere attrition may contribute to aberrant stem cell functions, methods to accurately measure telomere length in stem cells from skeletal muscles have not been demonstrated. Here, we have optimized and validated such a method, named MuQ-FISH, for analyzing telomere length in MuSCs from either mice or humans. Our analysis showed no differences in telomere length between young and aged MuSCs from uninjured wild-type mice, but MuSCs isolated from young dystrophic mice exhibited significantly shortened telomeres. In corroboration, we demonstrated that telomere attrition is present in human dystrophic MuSCs, which underscores its importance in diseased regenerative failure. The robust technique described herein provides analysis at a single-cell resolution and may be utilized for other cell types, especially rare populations of cells.

Posttraumatic Tibiofibular Synostosis After Treatment of Distal Tibiofibular Fractures in Children.

INTRODUCTION: Posttraumatic pediatric distal tibiofibular synostosis is a rare complication following fracture. This is a retrospective, multicenter case series of synostosis of distal tibiofibular fractures in children. The purpose was to evaluate the incidence and pattern of posttraumatic distal tibiofibular synostosis in children. METHODS: Of the 604 pediatric distal tibiofibular fractures, 20 patients (3.3%) with synostosis after treatment of distal tibiofibular fractures were identified at 3 tertiary referral centers. There were 12 boys and 8 girls, with a mean age of 8.4±2.0 years (range, 3.7 to 11.5 y) at the time of injury. Medical records were reviewed, and serial radiographs were analyzed to determine fracture configuration, pattern of synostosis, and changes in the relative positions of the proximal and distal tibial and fibular physes and in the alignment of the ankle. RESULTS: The time from the occurrence of fracture until the recognition of the synostosis ranged from 2 to 6 months (mean, 2.8 mo). The most common fracture configuration was oblique tibial fracture combined with comminuted fibular fracture. There were 12 focal types and 8 extensive types. The proximal tibiofibular distance was decreased in 13 patients. Proximal migration of the distal fibular physis developed in all cases. Five patients exhibited ankle valgus of 10 degrees or greater with moderate or severe distal fibular shortening. Eight patients were symptomatic after synostosis and 12 patients were asymptomatic. CONCLUSIONS: We identified 2 patterns of synostosis after the treatment of pediatric distal tibiofibular fracture: focal and extensive. The focal type was more prevalent than the extensive type, which was more likely to occur due to high-energy injury. When a tibiofibular cross-union develops, it creates growth abnormalities that warrant observation and potential treatment, as it may lead to progressive deformity or ankle pain. LEVEL OF EVIDENCE: Level IV.

Surgical Correction of Scoliosis in Patients With Duchenne Muscular Dystrophy: 30-Year Experience.

BACKGROUND: The natural history of scoliosis in Duchenne muscular dystrophy (DMD) is progressive and debilitating if neglected. The purpose of this study was to evaluate outcomes related to spinal deformity surgery in patients with DMD over a 30-year period. METHODS: This was a single center retrospective study of all operatively treated scoliosis in DMD patients over 30 years. Minimum follow-up was 2 years. Owing to changes in instrumentation over time, patients were divided into 2 groups: Luque or pedicle screws (PS) constructs. Radiographic, perioperative variables, pulmonary function test (preoperatively and postoperatively), and complication data were evaluated. RESULTS: There were 60 subjects (Luque: 47, PS: 13). The Luque group was on average 13 years old, 53 kg, and had 7 years of follow-up. Coronal Cobb was 31±12 degrees preoperatively, 16±11 degrees at first postoperatively, and 21±15 degrees at final follow-up (P≤0.001). Pelvic obliquity was 7±6 degrees preoperatively, 5±5 degrees at first postoperatively (P=0.43), and 5±4 degrees at final follow-up (P=0.77). The majority of this group was fused to L5 (45%) or the sacrum (49%). The PS group was on average 14 years old, 65 kg, and had 4 years of follow-up. Coronal Cobb was 43±19 degrees preoperatively, 12±9 degrees at first postoperatively (P≤0.001), and 12±8 degrees at final follow-up. Pelvic obliquity was 6±5 degrees preoperatively, 3±3 degrees at first postoperatively (P=0.06), and 2±2 degrees at final follow-up (P=0.053). The majority were fused to the pelvis (92%). Both groups' pulmonary function declined with time. Both groups had high complication rates (Luque 68%; PS group 54%). The Luque group had more implant-related complications (26%); the PS group had a higher rate of early postoperative infections (23%). CONCLUSIONS: Over a 30-year period of operative treatment of scoliosis in DMD, both PS constructs and Luque instrumentation improved coronal Cobb. The PS group had improved and maintained pelvic obliquity. Both groups had high complication rates. LEVEL OF EVIDENCE: Level IV-therapeutic.

Evaluation of Brace Treatment for Infant Hip Dislocation in a Prospective Cohort: Defining the Success Rate and Variables Associated with Failure.

BACKGROUND: The use of a brace has been shown to be an effective treatment for hip dislocation in infants; however, previous studies of such treatment have been single-center or retrospective. The purpose of the current study was to evaluate the success rate for brace use in the treatment of infant hip dislocation in an international, multicenter, prospective cohort, and to identify the variables associated with brace failure. METHODS: All dislocations were verified with use of ultrasound or radiography prior to the initiation of treatment, and patients were followed prospectively for a minimum of 18 months. Successful treatment was defined as the use of a brace that resulted in a clinically and radiographically reduced hip, without surgical intervention. The Mann-Whitney test, chi-square analysis, and Fisher exact test were used to identify risk factors for brace failure. A multivariate logistic regression model was used to determine the probability of brace failure according to the risk factors identified. RESULTS: Brace treatment was successful in 162 (79%) of the 204 dislocated hips in this series. Six variables were found to be significant risk factors for failure: developing femoral nerve palsy during brace treatment (p = 0.001), treatment with a static brace (p < 0.001), an initially irreducible hip (p < 0.001), treatment initiated after the age of 7 weeks (p = 0.005), a right hip dislocation (p = 0.006), and a Graf-IV hip (p = 0.02). Hips with no risk factors had a 3% probability of failure, whereas hips with 4 or 5 risk factors had a 100% probability of failure. CONCLUSIONS: These data provide valuable information for patient families and their providers regarding the important variables that influence successful brace treatment for dislocated hips in infants. LEVEL OF EVIDENCE: Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Nonossifying fibromas of the distal tibia: possible etiologic relationship to the interosseous membrane.

PURPOSE: Nonossifying fibromas (NOFs) present in a characteristic pattern in the distal tibia. Their predilection to this region and etiology remain imprecisely defined. METHODS: We performed a retrospective chart review of patients between January 2003 and March 2014 for distal tibial NOFs. We then reviewed radiographs (XRs), computed tomography (CT), and magnetic resonance imaging (MRI) for specific lesion characteristics. RESULTS: We identified 48 distal tibia NOFs in 47 patients (31 male, 16 female; mean age 12.3 years, range 6.9-17.8). This was the second most common location in our population (30 % of NOFs), behind the distal femur (42 %). Thirty-four lesions had CT and nine had MRI. Thirty-one percent were diagnosed by pathologic fracture. Ninety-six percent of lesions were located characteristically in the distal lateral tibia by plain radiograph, in direct communication with the distal extent of the interosseous membrane on 33 of the 34 (97 %) lesions with CT available for review and all nine (100 %) with MRI. The remaining two lesions occurred directly posterior. CONCLUSIONS: The vast majority of distal tibial NOFs occur in a distinct anatomic location at the distal extent of the interosseous membrane, which may have etiologic implications. LEVEL OF EVIDENCE: IV (case series).

What Risk Factors and Characteristics Are Associated With Late-presenting Dislocations of the Hip in Infants?

BACKGROUND: Most infants with developmental dysplasia of the hip (DDH) are diagnosed within the first 3 months of life. However, late-presenting DDH (defined as a diagnosis after 3 months of age) does occur and often results in more complex treatment and increased long-term complications. Specific risk factors involved in late-presenting DDH are poorly understood, and clearly defining an associated set of factors will aid in screening, detection, and prevention of this condition. QUESTIONS/PURPOSES: Using a multicenter database of patients with DDH, we sought to determine whether there were differences in (1) risk factors or (2) the nature of the dislocation (laterality and joint laxity) when comparing patients with early versus late presentation. METHODS: A retrospective review of prospectively collected data from a multicenter database of patients with dislocated hips was conducted from 2010 to 2014. Baseline demographics for fetal presentation (cephalic/breech), birth presentation (vaginal/cesarean), birth weight, maternal age, maternal parity, gestational age, family history, and swaddling history of patients were compared among nine different sites for patients who were enrolled at age younger than 3 months and those enrolled between 3 and 18 months of age. A total of 392 patients were enrolled at baseline between 0 and 18 months of age with at least one dislocated hip. Of that group, 259 patients were younger than 3 months of age and 133 were 3 to 18 months of age. The proportion of patients with DDH who were enrolled and followed at the nine participating centers was 98%. RESULTS: A univariate/multivariate analysis was performed comparing key baseline demographics between early- and late-presenting patients. After controlling for relevant confounding variables, two variables were identified as risk factors for late-presenting DDH as compared with early-presenting: cephalic presentation at birth and swaddling history. Late-presenting patients were more likely to have had a cephalic presentation than early-presenting patients (88% [117 of 133] versus 65% [169 or 259]; odds ratio [OR], 5.366; 95% confidence interval [CI], 2.44-11.78; p < 0.001). Additionally, late-presenting patients were more likely to have had a history of swaddling (40% [53 of 133] versus 25% [64 of 259]; OR, 2.053; 95% CI, 1.22-3.45; p = 0.0016). No difference was seen for sex (p = 0.63), birth presentation (p = 0.088), birth weight (p = 0.90), maternal age (p = 0.39), maternal parity (p = 0.54), gestational age (p = 0.42), or family history (p = 0.11) between the two groups. Late presenters were more likely to present with an irreducible dislocation than early presenters (56% [82 of 147 hips] versus 19% [63 of 333 hips]; OR, 5.407; 95% CI, 3.532-8.275; p < 0.001) and were less likely to have a bilateral dislocation (11% [14 of 133] versus 28% [73 of 259]; OR, 0.300; 95% CI, 0.162-0.555; p = 0.002). CONCLUSIONS: Those presenting with DDH after 3 months of age have fewer of the traditional risk factors for DDH (such as breech birth), which may explain the reason for a missed diagnosis at a younger age. In addition, swaddling history was more common in late-presenting infants. A high index of suspicion for DDH should be maintained for all infants, not just those with traditional risk factors for DDH. Further investigation is required to determine if swaddling is a risk factor for the development of hip dislocations in older infants. More rigorous examination into traditional screening methods should also be performed to determine whether current screening is sufficient and whether late-presenting dislocations are present early and missed or whether they develop over time. LEVEL OF EVIDENCE: Level III, retrospective study.

Talocalcaneal Coalitions.

Talocalcaneal coalitions present with complaints of flatfeet, foot or ankle pain after minor injury, or recurrent ankle sprains. Physical examination findings include limited subtalar motion and prominence inferior to the medial malleolus. Use of computed topography (CT) scan is recommended for preoperative planning. Confirmation of resection with intraoperative CT. Resection of talocalcaneal coalitions with fat-graft interposition has superior results to primary arthrodesis. Improved outcomes have been reported after resection, with foot scores averaging 90/100 (AOFAS).

In search of Ortolani: the man and the method.

Dr Marino Ortolani was an Italian pediatrician who developed a test for hip instability in the infant (1936) and then promoted early diagnosis of this condition to the medical community. He studied the pathoanatomy of hip instability in the 1940s. He wrote his textbook in 1948 and in 1952 he produced a movie about the examination and treatment of hip dysplasia which was translated into many languages to promote early diagnosis and treatment of developmental dysplasia of the hip (DDH). In his career, he wrote a monograph and 31 articles on the subject of hip dysplasia and besides his classic test he developed various braces to treat the infants with hip instability. A remarkable achievement for this early clinician-scientist.

Preliminary radiographic outcomes of surgical correction in juvenile hallux valgus: single proximal, single distal versus double osteotomies.

BACKGROUND: Surgical correction of juvenile hallux valgus has a high risk of recurrence and complications. This short-term follow-up study evaluates the radiographic differences between 3 osteotomy types: distal first metatarsal osteotomy, proximal first metatarsal osteotomy, and double first metatarsal osteotomy with regard to ability to achieve correction and the risk of hallux varus. METHODS: A total of 106 feet were evaluated. Percent correction of hallux valgus angle (HVA), intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA) was recorded, as well as complication and reoperation rates. Radiographs were evaluated at the initial visit, intraoperatively, and at final follow-up. RESULTS: The single distal osteotomy achieved: IMA within normal limits 21% of the time with no cases of overcorrection; HVA within normal limits 42% of the time with 13% overcorrected; and DMAA within normal limits 46% of the time with 4% overcorrected.The single proximal osteotomy achieved: IMA within normal limits 36% of the time with no cases of overcorrection; HVA within normal limits 36% of the time with no cases of overcorrection; and DMAA within normal limits 36% of the time with 7% overcorrected.The double osteotomy achieved: IMA within normal limits 54% of the time with no cases of overcorrection; HVA within normal limits 40% of the time with 7% overcorrected; and DMAA within normal limits 56% of the time with 22% overcorrected.The rate of HVA overcorrection was not found to be correlated with osteotomy type (P=0.37). The double osteotomy was found to have a higher DMAA overcorrection rate than either single osteotomy (P<0.001). CONCLUSIONS: The single distal osteotomy for juvenile hallux valgus seems to have the most consistent outcomes, with improved radiographic parameters and low risk of complication compared with the other surgical cohorts. However, the double osteotomy can have the best correction of all 3 radiographic parameters at once, but the highest risk for overcorrection of the DMAA. LEVEL OF EVIDENCE: Level III-retrospective case control study.

Fundamental concepts of developmental dysplasia of the hip.

To provide the best possible care to patients with developmental dysplasia of the hip, it is helpful to understand the normal growth and development of the hip joint; the pathoanatomy, epidemiology, and diagnosis of the condition; and the natural history of a missed diagnosis of dislocation, subluxation, and dysplasia.

C sign: talocalcaneal coalition or flatfoot deformity?

BACKGROUND: C sign is used to alert the physician of the possible presence of talocalcaneal coalition (TCC), so that advanced imaging can be ordered. The purpose of this study was to know the prevalence of the C sign among patients with TCC and its relationship to the presence of a TCC or to hindfoot alignment. METHODS: Retrospective reviews of the presence of C sign in radiographs of 88 feet with TCC (proved by computed tomography scan or surgical findings) and 260 flexible flatfeet were conducted. C sign was classified as complete and interrupted (types A, B, and C). The interobserver variability of the C sign was studied. Seven radiographic parameters were measured to analyze the relationship of these measurements with the presence or absence of the C sign. RESULTS: C sign was present in 68 feet (77%) with TCC: 14.5% complete and 62.5% interrupted (26% type A, 19.5% type B, and 17% type C). C sign was present in 116 flatfeet (45%), all of them interrupted (0.4% type A, 5.5% type B, and 39% type C). The talo-first metatarsal angle, the talohorizontal angle, the calcaneal pitch, the calcaneo-fifth metatarsal angle, and the naviculocuboid overlap presented a more pathologic value when a C sign was present. The κ-value for the presence of a C sign was 0.663. CONCLUSIONS: The so-called true C sign (complete or interrupted type A) indicates the presence of a TCC and it is not related to flatfoot deformity. However, it is only present in 41% of the cases. The interrupted C sign is much more likely to be related to flatfoot deformity than to the presence of a TCC, specifically when a type C is found. LEVEL OF EVIDENCE: Diagnostic Study level I.