Asymptomatic Hips Research Articles

COMPARISON OF PROPHYLACTIC IN-SITU SCREW FIXATION VERSUS OBSERVATION OF THE ASYMPTOMATIC CONTRALATERAL HIP IN SLIPPED CAPITAL FEMORAL EPIPHYSIS (SCFE)

BACKGROUND: Prophylactic fixation of the asymptomatic, radiographically-normal contralateral hip after unilateral (SCFE) is controversial. Children with unilateral SCFE whose contralateral hip is observed are at risk for having a contralateral slip and associated complications such as avascular necrosis (AVN). On the other hand, prophylactic pinning may be an unnecessary surgery that may also result in substantial complications. A comparison of the two treatment options has not been performed. This study seeks to compare the outcomes and nature of complications of patients whose contralateral hip was observed with those whose hip underwent prophylactic in-situ screw fixation. METHODS: We retrospectively reviewed 197 patients treated for a unilateral SCFE over 20 years between the 1997 and 2017 at two hospitals. Medical records and x-rays were reviewed, and variables of interest included age, sex, body mass index (BMI), Modified Oxford Bone Age Score (MOBA) at presentation, length of operation, estimated blood loss (EBL), and length of hospitalization. Additionally, postoperative complications/outcomes such as reoperation in the unaffected hip, pain in the unaffected hip, AVN, chondrolysis, infection. abnormal gait (limp), reslipped epiphysis (growth off of the implanted screw), degenerative joint disease, and development of a limb length discrepancy were recorded. RESULTS: Of the 197 total patients (mean age 11.8) treated for unilateral SCFE, 100 (51%) received prophylactic fixation of their unaffected, contralateral hip and 97 (49%) were observed. Average follow up was 24.5 months. A statistically significant difference was found between groups for age, MOBA Score, EBL, and operative time. No difference was found between groups for BMI, BMI %ile, and length of hospitalization. The unilateral group was older (p<0.001) and had a greater MOBA Score (p=0.006) compared to the prophylactic group (Table 1). Patients in the prophylactic group had greater EBL during surgery (p=0.004) and longer operative time (p<0.001) compared to the unilateral group. In those patients whose contralateral hip was observed, 19% developed a contralateral SCFE which required later in-situ fixation. Amongst those, 2/19 (10%) developed AVN or chondrolysis of the contralateral hip (2% overall). For the contralateral hip, 17/97 (17%) developed hip pain, 10/97 (10%) developed a leg length difference and 24/97 (24%) developed a limp. In those patients who had prophylactic fixation, for the contralateral hip 2/100 (2%) developed AVN, (3/100) 3% required reoperation, 1/100 (1%) developed an infection, 10/100 (10%) developed contralateral hip pain, 4/100 (4%) developed a LLD, and 26/100 (26%) developed a limp. CONCLUSIONS: Surgeons and patients should be able to compare outcomes when deciding whether or not to prophylactically fix the asymptomatic contralateral hip in SCFE. For patients with unilateral SCFE, there are similar rates of AVN (2%) of the asymptomatic contralateral hip whether the hip is prophylactically pinned or observed. Between the two treatment options, there are similar outcomes for length of hospital stay, EBL, rate of infection and development of a limp. There is a higher rate of a LLD and the need for another operation in patients whose contralateral asymptomatic hip is observed, rather than prophylactically pinned. [Table: see text]

PEDIATRIC PATIENTS WITH FAI AND INFLAMMATORY COMORBIDITIES HAVE A CHARACTERISTIC CAM DEFORMITY: A PILOT STUDY

Background: Pediatric patients with inflammatory conditions often present with single or multifocal joint pain. Assessment of these patients at our institution revealed a possible association between femoroacetabular impingement (FAI) and inflammatory comorbidities. The purpose of this study was to investigate the prevalence and unique characteristic morphology of FAI in pediatric patients with inflammatory comorbidities. Methodology: A retrospective review was conducted on a consecutive series of 105 patients diagnosed with FAI in our institution’s adolescent hip clinic from January 2016 to March 2018. Patients with an inflammatory comorbidity were identified. Femoral head-neck junction morphology was assessed qualitatively and with standard radiographic measures for FAI. Results: Seven patients (6.7% of diagnosed patients), with eight symptomatic hips, were found to have FAI and an inflammatory comorbidity. These diagnoses included Crohn’s disease, Celiac disease, juvenile idiopathic arthritis, Type 1 diabetes mellitus and hypothyroidism. All seven patients had cam deformities. Qualitative assessment revealed that most patients had a characteristic head-neck morphology that was unique to this subset of patients, with a prominent and “sharp-edged” bump at the head-neck junction (See Figure 1). Radiographic analysis of the symptomatic hips revealed a mean alpha angle of 81.3o (±8.7 o), mean LCEA of 33.1o (±8.4 o) and mean femoral offset of 0.07 (±0.05). There was no significant difference in the radiographic measurements between symptomatic and asymptomatic hips in these patients. Conclusion: This is the first study to identify an association between FAI and inflammatory comorbidities in pediatric patients, with a prevalence of 6.7% at our institution. Given the relative rarity of inflammatory comorbidities in the general pediatric patient, this represents an unexpectedly high association. These patients presented with a unique head-neck morphology characterized by a more prominent and “sharp-edged” cam lesion than the typical morphology seen in patients without an inflammatory comorbidity. This study raises questions regarding the possible role of physeal inflammation in the development of cam deformities and indicates a need for further studies investigating the relationship between systemic inflammatory disorders and FAI. [Figure: see text]

BODY IMAGE AND ITS ROLE IN YOUTH SPORTS PARTICIPATION

Background: Pediatric patients with inflammatory conditions often present with single or multifocal joint pain. Assessment of these patients at our institution revealed a possible association between femoroacetabular impingement (FAI) and inflammatory comorbidities. The purpose of this study was to investigate the prevalence and unique characteristic morphology of FAI in pediatric patients with inflammatory comorbidities. Methodology: A retrospective review was conducted on a consecutive series of 105 patients diagnosed with FAI in our institution’s adolescent hip clinic from January 2016 to March 2018. Patients with an inflammatory comorbidity were identified. Femoral head-neck junction morphology was assessed qualitatively and with standard radiographic measures for FAI. Results: Seven patients (6.7% of diagnosed patients), with eight symptomatic hips, were found to have FAI and an inflammatory comorbidity. These diagnoses included Crohn’s disease, Celiac disease, juvenile idiopathic arthritis, Type 1 diabetes mellitus and hypothyroidism. All seven patients had cam deformities. Qualitative assessment revealed that most patients had a characteristic head-neck morphology that was unique to this subset of patients, with a prominent and “sharp-edged” bump at the head-neck junction (See Figure 1). Radiographic analysis of the symptomatic hips revealed a mean alpha angle of 81.3o (±8.7 o), mean LCEA of 33.1o (±8.4 o) and mean femoral offset of 0.07 (±0.05). There was no significant difference in the radiographic measurements between symptomatic and asymptomatic hips in these patients. Conclusion: This is the first study to identify an association between FAI and inflammatory comorbidities in pediatric patients, with a prevalence of 6.7% at our institution. Given the relative rarity of inflammatory comorbidities in the general pediatric patient, this represents an unexpectedly high association. These patients presented with a unique head-neck morphology characterized by a more prominent and “sharp-edged” cam lesion than the typical morphology seen in patients without an inflammatory comorbidity. This study raises questions regarding the possible role of physeal inflammation in the development of cam deformities and indicates a need for further studies investigating the relationship between systemic inflammatory disorders and FAI. [Figure: see text]

Effect of leg-length discrepancy following total hip arthroplasty on collapse of the contralateral hip in bilateral non-traumatic osteonecrosis of the femoral head.

The purpose of this study was to examine whether leg-length discrepancy (LLD) following unilateral total hip arthroplasty (THA) affects the incidence of contralateral head collapse and subsequent THA in patients with bilateral osteonecrosis, and to determine factors associated with subsequent collapse. We identified 121 patients with bilateral non-traumatic osteonecrosis who underwent THA between 2003 and 2011 to treat a symptomatic hip, and who also exhibited medium-to-large lesions (necrotic area ≥ 30%) in an otherwise asymptomatic non-operated hip. Of the 121 patients, 71 were male (59%) and 50 were female (41%), with a mean age of 51 years (19 to 71) at the time of initial THA. All patients were followed for at least five years and were assessed according to the presence of a LLD (non-LLD vs LLD group), as well as the LLD type (longer non-operated side vs shorter non-operated side group). Overall, 68 hips (56%) became painful and progressed to collapse at a mean of 2.6 years (0.2 to 13.8), resulting in 59 THAs (49%). The five-year collapse-free survival rate for the non-LLD group was 59% (95% confidence interval (CI) 46.8 to 71.8) compared with 45% (95% CI 32.9 to 57.5) for the LLD group (p = 0.036), and 66% (95% CI 55.2 to 77.2) for the longer non-operated side group compared with 32% (95% CI 19.1 to 44.9) for the shorter non-operated side group (p < 0.001). Multivariate regression analyses found that large lesions had a higher risk of collapse than medium-size lesions (odds ratio (OR) 4.19, 95% confidence interval (CI) 1.69 to 10.38; p = 0.002). Meanwhile, patients with a LLD < 3 mm (OR 0.20, 95% CI 0.08 to 0.52; p = 0.001) or a longer non-operated leg (OR 0.11, 95% CI 0.04 to 0.28; p < 0.001) after THA were less likely to experience a subsequent collapse. We found that LLD may be a modifiable risk factor for femoral head collapse. Minimizing LLD and particularly avoiding a shorter non-operated limb after THA may lead to a lower risk of collapse of the asymptomatic hip in patients with bilateral non-traumatic osteonecrosis. Cite this article: Bone Joint J 2019;101-B:303-310.

Prevalence of labrum and articular cartilage injuries of the hip on 3T magnetic resonance imaging of asymptomatic elite soccer players

ObjectiveTo establish the prevalence of lesions of the labrum and articular cartilage of the hip in asymptomatic elite soccer players by performing 3T magnetic resonance imaging. MethodsEighty-four asymptomatic hips of 42 professional soccer players were evaluated. Male subjects older than 18 years were included. Cam and pincer deformity were defined as an alpha angle greater than 55 degrees and a lateral centre edge angle greater than 39 degrees, respectively. Labral injuries were classified with the Czerny classification and cartilage damage was classified with the Outerbridge classification. Specific statistical tests were used to establish the relationship between anatomical variances of the hip and the presence of chondral and labral injuries. ResultsFAI morphology prevalence was 25%. Abnormalities such as cam (22.5%) and labral injuries (33.8%) were found. Those cases with reported labral injury were predominantly intrasubstance damage (18.8%). Anatomical features of FAI were found to be related to lesions of the femoral cartilage (p<.001), chondrolabral damage (p=.042), or both injuries (p<.001). ConclusionAsymptomatic labral or cartilaginous injuries of the hip were reported in 25% of the included professional soccer players. These injuries were associated with anatomical features of FAI.

Reference values and variation of acetabular angles measured by computed tomography in 170 asymptomatic hips.

BackgroundWe have little knowledge of reference values for acetabular angles.PurposeThe purpose of this study was to report values and variation for the center-edge (CE), the acetabular-index (AI),...

Does Cartilage Degenerate in Asymptomatic Hips With Cam Morphology?

The management of asymptomatic individuals with cam femoral morphology that predisposes their hips to femoroacetabular impingement has received little attention. Such hips may have subclinical articular damage; however, whether this cartilage damage will progress is unknown as is whether any particular bone morphologies are associated with this progression. Such knowledge could help determine the natural history and guide management of such individuals. The purpose of this study was to determine whether (1) asymptomatic hips with cam morphology are at risk of further cartilage degeneration (as evaluated by T1ρ); (2) T1ρ changes are predictive of symptom onset; and (3) bony morphologic parameters are associated with T1ρ signal changes. In a prospective, longitudinal study, 17 asymptomatic volunteers/hips (16 men; 33 ± 6 years) with cam morphology underwent two T1ρ MRI scans and functional assessment (WOMAC) at recruitment and at 4 years (range, 2-6 years). Volunteers were recruited from a previous study, which reported on the prevalence of cam morphology among asymptomatic individuals using hip MRI; cam morphology was defined as an α angle ≥ 60° anterolaterally and/or ≥ 50.5° anteriorly relative to the neck axis. The differences in T1ρ values (ΔT1ρ) and relative differences (%ΔT1ρ) were calculated as: ΔT1ρ = T1ρFollowup - T1ρInitial and %ΔT1ρ = ΔT1ρ/T1ρInitial. A %ΔT1ρ > 17.6% was considered clinically important. Using CT data, femoral, acetabular, and spinopelvic parameters were measured. Whether ΔT1ρ and/or %ΔT1ρ was associated with any of the bone morphologic parameters was tested using Spearman's correlation coefficient. The global T1ρ in these asymptomatic hips with cam morphology remained unchanged between initial (mean, 35 ± 5 ms) and followup scans (mean, 34 ± 3 ms; p = 0.518). No differences with the numbers available in T1ρ values were seen initially between the anterolateral and posterolateral (34 ± 6 ms versus 33 ± 4 ms; p = 0.734) regions; at followup, T1 values were higher posterolaterally (36 ± 5 ms versus 32 ± 5 ms; p = 0.031). The mean global ΔT1ρ was 1 ± 5 ms (95% confidence interval, -1 to +3 ms) and the mean global %ΔT1ρ was 2% ± 13%. Two volunteers reported lower WOMAC scores; one patient exhibited a clinically important increase in %ΔT1ρ (-26%). The degree of acetabular coverage correlated with %ΔT1ρ (rho = 0.59-0.61, p = 0.002); the lesser the acetabular coverage anterolaterally, the greater the corresponding area's T1ρ at followup. Although signs of posterolateral joint degeneration were detected, these were not generally associated with symptoms, and only one of the two volunteers with the onset of symptoms had a clinically important increase in %ΔT1ρ. We found that reduced acetabular coverage may increase the likelihood that preclinical cartilage degeneration will arise within 2 to 6 years; thereby reduced acetabular coverage should be considered when stratifying asymptomatic hips at risk of degeneration. Future studies should be performed with a larger cohort and include femoral version among the parameters studied. Level II, diagnostic study.

CORR Insights®: What Is the Prevalence of Cam Deformity After Prophylactic Pinning of the Contralateral Asymptomatic Hip in Unilateral Slipped Capital Femoral Epiphysis? A 10-year Minimum Followup Study.

CORR Insights®: What Is the Prevalence of Cam Deformity After Prophylactic Pinning of the Contralateral Asymptomatic Hip in Unilateral Slipped Capital Femoral Epiphysis? A 10-year Minimum Followup Study.

Prevalencia de lesiones del labrum y del cartílago articular de la cadera en imagen por resonancia magnética simple 3 T de futbolistas profesionales asintomáticos

ObjectiveTo establish the prevalence of lesions of the labrum and articular cartilage of the hip in asymptomatic elite soccer players by performing 3T magnetic resonance imaging. MethodsEighty-four asymptomatic hips of 42 professional soccer players were evaluated. Male subjects older than 18 years were included. Cam and pincer deformity were defined as an alpha angle greater than 55 degrees and a lateral centre edge angle greater than 39 degrees, respectively. Labral injuries were classified with the Czerny classification and cartilage damage was classified with the Outerbridge classification. Specific statistical tests were used to establish the relationship between anatomical variances of the hip and the presence of chondral and labral injuries. ResultsFAI morphology prevalence was 25%. Abnormalities such as cam (22.5%) and labral injuries (33.8%) were found. Those cases with reported labral injury were predominantly intrasubstance damage (18.8%). Anatomical features of FAI were found to be related to lesions of the femoral cartilage (P<.001), chondrolabral damage (P=.042), or both injuries (P<.001). ConclusionAsymptomatic labral or cartilaginous injuries of the hip were reported in 25% of the included professional soccer players. These injuries were associated with anatomical features of FAI.

CORR Insights®: Acetabular Labral Tears Are Common in Asymptomatic Contralateral Hips With Femoroacetabular Impingement.

CORR Insights®: Acetabular Labral Tears Are Common in Asymptomatic Contralateral Hips With Femoroacetabular Impingement.

Differences in magnetic resonance findings between symptomatic and asymptomatic pre-collapse osteonecrosis of the femoral head

PurposeThe purpose of this study was to assess the differences in magnetic resonance (MR) findings between the symptomatic and asymptomatic pre-collapse stage of osteonecrosis of the femoral head (ONFH). Materials and methodsThis study reviewed 123 consecutive hips in 91 patients in the pre-collapse stage of ONFH based on plain radiographic findings. These 123 hips were divided into symptomatic and asymptomatic groups according to the pain domain score in the Harris hip score system. Bone marrow edema (BME), synovial fluid effusion, and subchondral fracture were evaluated using MR imaging. Odds ratios (ORs) were calculated between these three parameters and symptoms. The subsequent clinical course after MR examination was also assessed for each hip that could be followed more than 1 year. ResultsForty-six hips (37.4%) were categorized as symptomatic and 77 hips (62.6%) as asymptomatic. The prevalence of BME, synovial fluid effusion, and subchondral fracture were 87.0% (40/46), 80.4% (37/46), and 34.8% (16/46), respectively, in the symptomatic group, and 0%, 28.6% (22/77), and 0%, respectively, in the asymptomatic group, indicating significant differences between the two groups (p < 0.0001). Among these parameters, BME showed the highest OR with regard to the presence or absence of symptoms (BME, 965.8; joint effusion, 10.3; subchondral fracture, 83.9). Due to persistent pain and subsequent collapse, 30 of 35 (85.7%) symptomatic hips with BME subsequently underwent surgical treatment at a mean interval of 3.47 months after MR examination, while 25 of 66 (37.9%) asymptomatic hips without BME underwent surgical treatment at a mean interval of 20.7 months after MR examination. ConclusionsThis study demonstrated that symptomatic pre-collapse ONFH diagnosed based on plain radiographic findings could be distinguished from asymptomatic pre-collapse ONFH by the presence of BME on MR imaging, and thus BME may be a sign of occult fracture.

Prevalence of radiologic acetabular dysplasia in asymptomatic Asian volunteers.

The purpose of this study was to evaluate the prevalence of acetabular dysplasia in an asymptomatic Asian population as one of the most important risk factors of hip osteoarthritis. From December 2014 to March 2015, we investigated the data of 200 asymptomatic volunteers (400 hips) aged 18–50 years recruited from our institution. Pelvic radiographs were taken and reviewed by two experienced orthopaedic surgeons. Lateral centre-edge (LCE) angle, Sharp angle, Tonnis angle and acetabular depth-to-width ratio (AD/WR) were measured. We investigated the mean values and identified the statistical differences between the sexes and evaluated the prevalence and bilaterality of acetabular dysplasia defined by each parameter. Mean LCE angle, Sharp angle, Tonnis angle and AD/WR were 26.2°, 41.3°, 8.5° and 0.28, respectively. All parameters showed more dysplastic results in females than in males and were statistically significantly different, except for AD/WR. When defined acetabular dysplasia as LCE angle <20°, Sharp angle >45°, Tonnis angle >14° or AD/WR <0.25, the prevalence of acetabular dysplasia by each parameter was 15.0%, 12.8%, 13.3% and 12.8%, respectively. There was a higher prevalence in females than in males; however, only Sharp and Tonnis angles showed significant differences. The bilaterality of acetabular dysplasia was 18.6–39.5% for all subjects. There is high prevalence of asymptomatic dysplastic hips in the Asian population.

What Is the Prevalence of Cam Deformity After Prophylactic Pinning of the Contralateral Asymptomatic Hip in Unilateral Slipped Capital Femoral Epiphysis? A 10-year Minimum Followup Study.

Prophylactic pinning of the asymptomatic and normal-appearing contralateral hip in patients with unilateral slipped capital femoral epiphysis (SCFE) remains controversial. Understanding the minimal 10-year clinical, functional, and radiographic outcomes of the contralateral asymptomatic hip in unilateral SCFE may be helpful in the decision regarding whether the benefits associated with potentially preventing a SCFE are outweighed by the risk of additional surgery. Among patients with SCFE treated with prophylactic pinning of the asymptomatic and contralateral hip, we sought (1) to determine the complications and reoperations; (2) to evaluate the development of cam deformities and the frequency and severity of osteoarthritis progression; and (3) to characterize hip pain and function as measured by the Harris hip score (HHS) and the Hip Disability and Osteoarthritis Outcome Score (HOOS) at minimal 10-year followup. Between 1998 and 2005 all patients with SCFE seen at our institution were treated with the modified Dunn procedure and all were offered prophylactic pinning of the contralateral asymptomatic hip. Of the 41 patients who underwent the unilateral modified Dunn procedure and who had an asymptomatic contralateral hip, 37 patients (90%) underwent pinning of that contralateral hip. Of those, 33 patients (80%) were available for clinical and radiographic evaluation for this retrospective study at a minimum of 10 years (mean followup 12 ± 2 years) after surgery. Three patients of the 37 patients only had 10-year clinical followup, including questionnaires sent by mail and telephone, because they refused further radiographic followup and one patient was lost to followup. The group included 19 males and 17 females whose age at surgery was a mean of 13 ± 2 years. Medical charts were reviewed and patients were asked about complications and additional surgical procedures. Most recent postoperative radiographs were evaluated for measurement of the alpha angle, head-neck offset, epiphysis orientation, and osteoarthritis grading according to Tönnis classification and minimum joint space width. The presence of a cam deformity was defined by an alpha angle measurement > 60° on the AP radiograph and/or > 55° on the lateral radiograph. Hip function and pain were assessed by the HHS and HOOS outcome measures. No complications with prophylactic in situ pinning were recorded. Four of 36 (11%) patients underwent subsequent surgical treatment for cam-type femoroacetabular impingement (FAI), and hardware removal was performed in four hips (11%). The mean alpha angle was 53° ± 8° on the AP radiograph and 49° ± 8° on the lateral view at followup. In total, 10 of 33 hips (30%) had a cam morphology at the femoral head-neck junction and four (12%) were symptomatic and underwent FAI surgery. Six of 33 patients (18%) developed an asymptomatic cam morphology at the femoral head-neck junction; in three of 33 hips (9%), the cam deformity instead of lesion were visible only on the lateral projection, and 9% were visible on both the AP and lateral projections. The preoperative offset of the femoral head-neck junction was 10 ± 3 mm on the AP view and 11 ± 4 mm on the lateral view. At followup, the AP offset was 7 ± 3 mm and the lateral offset was 6 ± 3 mm, and on the lateral view, the offset was < 10 mm in eight hips (22%). No patient had radiographic signs of hip osteoarthritis (Tönnis Grade 0). The mean minimum joint space width was 4 ± 0.4 mm. The mean HHS for the 32 patients who did not undergo subsequent surgery was 97 ± 5 at latest followup. The mean postoperative HOOS was 94 ± 8 for the 32 patients at latest followup. At a minimum followup of 10 years after prophylactic pinning of a contralateral asymptomatic hip, most patients achieve excellent hip scores; however, a substantial proportion will develop a symptomatic cam deformity despite prophylactic pinning. No patient had signs of osteoarthritis at a minimum of 10 years, but almost one-third of the patients who underwent prophylactic pinning developed a cam deformity. Level IV, therapeutic study.

Acetabular Labral Tears Are Common in Asymptomatic Contralateral Hips With Femoroacetabular Impingement.

The number of patients undergoing hip arthroscopy for labral tears has increased, but labral tears are sometimes seen in asymptomatic patients with femoroacetabular impingement (FAI). The frequency of this finding, however, has not been well characterized nor is the proportion of patients with previously asymptomatic labral tears who may later become symptomatic. The purpose of this study was to determine (1) the prevalence of labral tears and other intraarticular pathology in the asymptomatic contralateral hip of patients undergoing surgery for symptomatic FAI; (2) the likelihood that the asymptomatic hip had become symptomatic at latest followup; and (3) any association between MRI findings and age, sex, and body mass index (BMI) in both symptomatic and asymptomatic sides. This study included patients who were diagnosed with unilateral symptomatic FAI between 2013 and 2015 and who had an available MRI of both hips. The study included 100 patients (47 females, 53 males) with a mean age of 33 years (range, 17-57 years). Patients with a symptomatic contralateral hip (n = 56) or an unsuitable MRI for review based on both reviewers' consensus (n = 344) were excluded. The MRI of both hips was independently evaluated by two orthopaedic surgeons and interobserver reliability tested. The interobserver reliability for the two surgeons' MRI ratings was almost perfect (κ ≥ 0.85). The presence of a labral tear, an acetabular chondral lesion, subchondral acetabular cysts, and fibrocystic changes in the femoral head-neck junction was documented for both hips. At latest followup, asymptomatic hips were investigated for any symptomatic labral tears or surgical procedures resulting from FAI. A labral tear was recorded in 97 (97%) and 96 (96%) of symptomatic hips, respectively, for each surgeon's evaluation. A labral tear was also detected in 41 (41%) and 43 (43%) of asymptomatic hips. In addition, an acetabular chondral lesion was detected in 32 (32%) and 35 (35%) of the symptomatic hips and 15 (15%) and 17 (17%) of the asymptomatic hips. At latest followup, nine of the patients were diagnosed with symptomatic labral tears in the contralateral asymptomatic hip and were treated. None of the radiologic parameters examined demonstrated an association with patient age, sex, or BMI in either symptomatic or asymptomatic hips. Labral tears and acetabular chondral lesions are common in the asymptomatic contralateral hip of patients undergoing surgery for FAI. The incidence of a symptomatic labral tear in these asymptomatic hips was 9% during 2 years of followup. We suggest that the decision to perform chondral or labral surgery in patients with FAI should be made with caution considering the relatively high prevalence of labral tears in asymptomatic hips and the low chance of development of symptoms. Level IV, case-series study.

MRI in idiopathic, stable, slipped capital femoral epiphysis: evaluation of contralateral pre-slip.

:PurposeEarly diagnosis and treatment of slipped capital femoral epiphysis (SCFE) is important to prevent slip progression and avoid complications. We sought to determine if MRI findings in patients with unilateral SCFE could indicate ‘pre-slip’ or predict future SCFE in the contralateral hip.MethodsA prospective study evaluated patients with unilateral SCFE over a two-year period. MRI of the asymptomatic hip was performed within the perioperative period. Patients were followed with radiographs until a contralateral slip occurred or until physeal closure. Demographics, clinical stability, severity, posterior slope angle (PSA), modified Oxford Bone Score (mOBS) and patency of the triradiate cartilage were recorded and statistical analysis performed.ResultsIn all, 33 of 54 patients with unilateral SCFE were enrolled into the study. In all, 29 (87.8%) had complete follow-up. Five of the enrolled patients (15.2%) developed a sequential slip requiring in situ pinning. Six of 33 (18.2%) patients had positive MRI findings: four of which proceeded to sequential SCFE and two which did not. One sequential slip had a negative MRI. PSA predicted 1/11 sequential slips (sensitivity 9.09%, specificity 81.4%, positive predictive value (PPV) 11.1%, negative predictive value (NPV) 77.8%) and mOBS predicted 5/11 sequential slips (sensitivity 45.5%, specificity 93%, PPV 62.5%, NPV 87%). An open triradiate cartilage was present in 8/11 patients with sequential slips (sensitivity 72.7%, specificity 81.4%, PPV 50%, NPV 92.1%).ConclusionMRI findings consistent with ‘pre-slip’ were present in 66.7% of patients who developed a sequential SCFE. Further study on the utility/sensitivity of MRI in predicting sequential SCFE is warranted.Level of EvidenceII, diagnostic

A Possible New Radiographic Predictor of Progression of Osteoarthritis in Developmental Dysplasia of the Hip: The Center Gap.

Patients with comparable severities of developmental dysplasia of the hip (DDH) may variably progress to osteoarthritis (OA) over time. Although joint congruency may be associated with OA progression in patients with DDH, it has only been assessed subjectively. We assessed the gap between the rotational centers of the acetabulum and femoral head (center gap) as a possible predictive measure of OA progression in patients with DDH. In patients with bilateral DDH, we asked: (1) What is the probability of OA progression (Tönnis grade) or symptom development (pain) in the asymptomatic contralateral hip of patients with DDH undergoing unilateral joint-preserving surgery? (2) Is the center gap measurement associated with OA progression or symptom development in these hips? (3) Is the center gap measurement correlated with previous radiographic parameters? A total of 297 patients (319 hips) underwent unilateral eccentric rotational acetabular osteotomy at our institution between July 1989 and December 1999. We performed no other joint-preserving surgery to treat patients with DDH during this timeframe. The inclusion criteria for the study were patients younger than 55 years of age, the contralateral hip classified as Tönnis Grade 0, no previous surgical interventions, and asymptomatic at the time of eccentric rotational acetabular osteotomy (155 patients, 155 hips). The exclusion criteria were a contralateral hip without dysplasia (four patients, four hips), loss to followup before 10 years (42 patients, 42 hips [27%]), or missing medical records or radiographs (21 patients, 21 hips [14%]). The remaining 88 patients (88 hips; 11 males and 77 females) with a mean age of 39 years (range, 17-53 years) and mean followup of 20 years (range, 10-27 years) were analyzed. From the institutional database, radiographic parameters including the center gap in the AP view were assessed using radiographs at the time of eccentric rotational acetabular osteotomy, and the Tönnis grade was recorded 1 year postoperatively and annually thereafter retrospectively. We defined migration of the rotational center of the femoral head based on the rotational center of the acetabulum in the horizontal plane as center gap X (mm) and in the vertical plane as center gap Y (mm) and defined the absolute value between the centers as center gap distance (mm). Using κ statistics, intra- and interobserver reliabilities were determined to be 0.896 and 0.857 for center gap X, 0.912 and 0.874 for center gap Y, and 0.912 and 0.901 for the center gap distance, respectively. When patients reported any contralateral ipsilateral hip pain during clinic visits, the hip was considered symptomatic. Kaplan-Meier survivorship analyses were performed with OA progression or symptom development in the nonoperative hip as the endpoint. Multivariate analyses were performed to assess risk factors for each outcome using the Cox proportional hazards model. Correlation analyses between the center gap and other parameters including lateral center-edge angle, femoral head extrusion index, acetabular depth-to-width index, femoral head lateralization, minimum width of the joint space, head sphericity, and joint congruency were performed using Pearson's correlation coefficient. At 20 years postoperatively, the probability of OA progression in the nonoperative hip was 13% (95% confidence interval [CI], 7.1-22.1) and the probability of symptom development was 34% (95% CI, 24.7-46.1). The center gap X measurements in the groups with OA progression (lateral 2.0 ± 2.1 [SD] mm) or symptom development (lateral 0.9 ± 2.4 mm) took a more lateral direction than those in the group without OA progression (medial 0.4 ± 2.1 mm) or symptom development (medial 0.5 ± 2.0 mm) (OA progression, p < 0.001; symptom development, p = 0.005). The center gap Y measurements in the groups with OA progression (distal 2.7 ± 7.1 mm) or symptom development (distal 2.1 ± 6.0 mm) took a more distal direction than those in the group without OA progression (proximal 1.6 ± 6.2 mm) or symptom development (proximal 2.5 ± 6.1 mm) (OA progression, p = 0.027; symptom development, p = 0.001). Independent risk factors for OA progression were the femoral head extrusion index (hazard ratio [HR], 1.11; 95% CI, 1.01-1.22; p = 0.028) and the center gap X (HR, 1.52; 95% CI, 1.07-2.16; p = 0.019), whereas no independent risk factors for symptom development were found. The center gap in the horizontal plane had no correlations with any other radiographic parameter studied. The center gap in the horizontal plane had a modest association with OA progression in this group of patients with DDH. Future studies are needed to determine the normal value of the center gap for patients without DDH and to assess the center gap in lateral radiographic views. Level IV, prognostic study.

Proximal iliotibial band thickness as a cause for recalcitrant greater trochanteric pain syndrome.

ABSTRACTTo investigate iliotibial band (ITB) diameter thickness at the greater trochanter in patients requiring iliotibial band release who have failed conservative modalities, in comparison to an asymptomatic patient population. A total of 68 subjects were selected to be reviewed using T2 axial plane MRI. The ITB diameter thickness was measured in 34 subjects who underwent surgical ITB release, and compared with a match-paired asymptomatic hip cohort consisting of 34 subjects. ITB diameter thickness was measured at the thickest location for each subject twice by two different examiners. Inter/intra class correlation coefficient was determined for ITB measurement technique accuracy, and the presence of recalcitrant proximal hip pain was evaluated. Interclass correlation coefficient with 95% confidence was measured to be 0.953. The average thickness for ITB surgical release subjects was measured to be 5.61 ± 2.10 mm, and for asymptomatic subjects 3.77 ± 0.79 mm (P < 0.001). The results of this study demonstrate a statistically significant positive relationship of an increased diameter thickness in the ITB in symptomatic patients who failed conservative therapy and underwent surgical intervention for treatment.

On a “Columbus’ Egg”: Modeling the shape of asymptomatic, dysplastic and impinged hip joints

Understanding morphological features that characterize normal hip joint is critical and necessary for a more comprehensive definition of pathological presentations, such as femoroacetabular impingement and hip dysplasia. Based on anatomical observations that articular surfaces of synovial joints are better represented by ovoidal shapes than by spheres, the aim of this study is to computationally test this morphological classification for the femoral head and acetabular cavity of asymptomatic, dysplastic and impinged hips by comparing spherical, ellipsoidal and ovoidal shapes. An image-based surface fitting framework was used to assess the goodness-of-fit of spherical, ellipsoidal and tapered ellipsoidal (i.e., egg-like) shapes. The framework involved image segmentation with active contour methods, mesh smoothing and decimation, and surface fitting to point clouds performed with genetic algorithms. Image data of the hip region was obtained from computed tomography and magnetic resonance imaging scans. Shape analyses were performed upon image data from 20 asymptomatic, 20 dysplastic and 20 impinged (cam, pincer, and mixed) hips of patients with ages ranging between 18 and 45 years old (28 male and 32 women). Tapered ellipsoids presented the lowest fitting errors (i.e., more oval), followed by ellipsoids and spheres which had the worst goodness-of-fit. Ovoidal geometries are also more representative of cam, pincer, mixed impinged hips when compared to spherical or ellipsoidal shapes. The statistical analysis of the surface fitting errors reveal that ovoidal shapes better represent both articular surfaces of the hip joint, revealing a greater approximation to the overall features of asymptomatic, dysplastic and impinged cases.

Age- and Sex-Specific Morphologic Variations of Capital Femoral Epiphysis Growth in Children and Adolescents Without Hip Disorders

Background:Understanding the development of the capital femoral epiphysis is essential to identify pathologic variations that may lead to cam morphology.Purpose/Hypothesis:The purpose of this study was to investigate the development of the capital femoral epiphysis during childhood and adolescence, with specific morphologic analysis of the peripheral growth and the metaphyseal surface of the growth plate. We hypothesized that age- and sex-dependent morphologic variations of the peripheral growth (cupping) and surface anatomy (epiphyseal tubercle) of the epiphysis would be evident with increasing age.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Pelvic computed tomography scans of 80 children and adolescents (range, 8-15 years; n = 10 per age group; 50% male), imaged because of suspected appendicitis, were used to reformat the proximal femur. All patients had asymptomatic hips with no signs or history of hip disorder. We measured the peripheral cupping of the epiphysis and the epiphyseal tubercle dimensions from 3-dimensional models. All measurements were normalized to the epiphyseal diameter. The effect of age on these parameters was evaluated by use of linear regression analysis. A 2-way analysis of variance (ANOVA) was used to compare these parameters between males and females.Results:The mean epiphyseal cupping increased with increasing age (R2 = 0.54; P < .001). The mean normalized epiphyseal cupping was consistently higher in the anterior and posterior directions compared with the inferior and superior locations. Male patients aged 10 and 11 years had lower (P = .002) mean epiphyseal cupping compared with female patients of the same age. We observed no difference between male and female participants after 12 years of age (P > .3). The normalized epiphyseal tubercle height (R2 = 0.08; P = .009), width (R2 = 0.13; P = .001), and length (R2 = 0.45; P < .001) decreased with increasing age, with no differences between male and female patients. On average, a 2.6-fold increase was found in epiphyseal cupping from 8 to 15 years of age, whereas normalized tubercle height decreased by 0.4-fold.Conclusion:Peripheral cupping of the epiphysis over the metaphysis increases with age, while the relative epiphyseal tubercle dimensions decrease. Females have an earlier onset of rapid increase in the peripheral cupping compared with males; however, no differences in epiphyseal tubercle dimensions were found between male and female patients. These findings may guide future studies investigating the development of cam morphology, which should consider the surface morphologic characteristics of the capital femoral epiphysis, the growth plate, and the differences in morphologic characteristics according to age and sex.

Gait asymmetries in unilateral symptomatic hip osteoarthritis and their association with radiographic severity and pain.

Little is known about the loading patterns in unilateral hip osteoarthritis (OA) and their relationship to radiographic severity and pain. We aimed to examine the loading patterns at the hips of those with unilateral symptomatic hip OA and identify associations between radiographic severity and pain with loading alterations. 61 subjects with symptomatic unilateral hip OA underwent gait analyses and evaluation for radiographic severity (Kellgren-Lawrence [KL]-grade) and pain (visual analogue scale) at bilateral hips. Hip OA subjects had greater range of motion and higher hip flexion, adduction, internal and external rotation moments at the contralateral, asymptomatic hip compared to the ipsilateral hip ( p < 0.05). Correlations were noted between increasing KL-grade and increasing asymmetry of contralateral to ipsilateral hip loading ( p < 0.05). There were no relationships with pain and loading asymmetry. Unilateral symptomatic hip OA subjects demonstrate asymmetry in loading between the hips, with relatively greater loads at the contralateral hip. These loading asymmetries were directly related to the radiographic severity of symptomatic hip OA and not with pain. Additional research is needed to determine the role of gait asymmetries in disease progression.