Hip dysplasia hiding in plain sight: A retrospective analysis of radiology reports

INTRODUCTION

Timely recognition of dysplastic hip morphology is critical to facilitate appropriate management before significant joint damage has developed. It is likely that radiologist under reporting contributes to delays in diagnosis. This study aimed to assess how often adult hip dysplasia goes undetected in radiological reports and to identify clinical and radiological variables that impact the likelihood of detection of dysplasia by radiologists.

METHODS

Referral details and radiology reports of patients who underwent periacetabular osteotomy by a single surgeon for symptomatic hip dysplasia between 1 January 2016 and 30 June 2020 were reviewed. Four assessors measured the lateral centre edge angle from the pelvic radiograph performed at time of referral. Film quality and other radiographic parameters were also assessed.

RESULTS

Sixty-eight patients were included, 84% were female and the median age was 28.1 years. Dysplasia was not documented in the radiology report in 49% of cases. Dysplasia was more likely to be reported with no history of injury, an aspherical femoral head, lower lateral centre edge angle, higher acetabular index, increased femoral head shaft angle, higher femoro-epiphyseal acetabular roof index, or if there was disruption of Shenton's line, with the first three variables being independent predictors of radiologist detection.

CONCLUSION

Hip dysplasia should be considered in all adolescents/young adults presenting with hip pain. Causes of radiologist under reporting are likely multifactorial. Clinical information can cause cognitive biases and result in selective looking. A systematic approach to pelvis radiographs should include assessment of acetabular coverage and active search for evidence of femoral head migration.

Assessment of the iliocapsularis muscle on magnetic resonance imaging

INTRODUCTION

Morphologic features of Iliocapsularis (IC) may aid clinical decision-making in the symptomatic hip. The relationship between IC muscle size and underlying hip pathology is emerging; however, research is limited in the imaging literature. The purpose of this study was to determine the reliability and reproducibility of measurements of the IC muscle and its MRI appearances. It also looked for any association between IC dimension and axial levels, side, gender and bony features of hip instability.

METHODS

Retrospective study of 37 MRI scans were assessed by four observers. MRI axial T1 images were used to define the IC anatomy, measure the IC and rectus femoris at the femoral head centre (FHC) and adjacent levels and calculate the iliocapsularis-to-rectus femoris (IR) ratio. Measurements were repeated at least 2 weeks later. Radiographic assessment of the lateral centre edge angle, acetabular index and femoral neck-shaft angle were also conducted.

RESULTS

The IC was always present, but was well-defined in only 4% of cases with fair agreement. The intraclass correlation coefficient for reliability and reproducibility was the highest for IC width 0.94 (0.91-0.96). No significant correlation was identified between the IR ratio and radiographic parameters.

CONCLUSION

Iliocapsularis is visible and reliably measured on MRI despite observers considering the muscle to be not well-defined. Despite gender differences in muscle size, the IR ratio was unchanged. There is a significant difference in the IR ratio above and below the FHC; therefore, clinicians need to be aware of how this may impact the clinical use when utilising the IR ratio.

The Effects of 20 Weeks of Side-Alternating Vibration Therapy on Physical Function, Bone and Muscle Health in Adolescents with Down Syndrome

AIMS

To evaluate the effects of side-alternating vibration therapy on physical function and body composition in adolescents with Down syndrome.

METHODS

Fourteen adolescents (8 males) with Down syndrome (mean ± SD age: 15.5 ± 2.3 years) performed vibration treatment nine minutes daily, four times per week, for 20 weeks on a Galileo vibration platform. Data were collected at baseline and after 20 weeks of intervention. Assessments included six-minute walk test, muscle function (force plate), whole-body dual-energy X-ray absorptiometry and peripheral quantitative computed tomography of the non-dominant tibia.

RESULTS

After 20 weeks, participants increased their distance walked in the six-minute walk test (p = 0.009), 2-leg single jump efficiency (p = 0.024) and jump velocity (p = 0.046). Participants also increased their power (p = 0.034) and reduced the time taken during the chair rise test (p < 0.001). At the total body level, increases were seen in bone mineral density (p = 0.004), bone mineral content (p = 0.043), fat free mass (p = 0.013) and lean mass (p = 0.021).

CONCLUSION

Side-alternating vibration therapy was associated with increases in physical function and muscle mass with no effects on bone health in adolescents with Down syndrome.

CLINICAL TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trial Registry (ACTRN12615000092594) - registered on 4^th February 2015.

Microinstability of the hip: a systematic review of the imaging findings

OBJECTIVES

To undertake a systematic review of the morphologic features associated with hip microinstability and determine whether there are suggestive or diagnostic imaging findings.

METHODS

Four electronic databases were searched up to September 2019 to identify original research reporting morphologic features in individuals with either a clinical diagnosis of hip microinstability (instability without overt subluxation/dislocation) or those with symptomatic laxity demonstrated on imaging (increased femoral head translation/distraction or capsular volume). Studies focussing on individuals with pre-existing hip conditions (including definite dysplasia (lateral centre edge angle < 20°), significant trauma, previous dislocation or surgery were excluded. Methodological quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies 2 tool.

RESULTS

Twenty-two studies met inclusion criteria (clinical diagnosis of microinstability n = 15 and demonstration of laxity n = 7). Imaging information gathered from the studies includes radiographs (n = 14), MRI (n = 6), MR arthrography (n = 4), CT (n = 1) and intraoperative examination. Most studies exhibited design features associated with an overall high or unclear risk of bias. Some dysplastic features are associated with microinstability or laxity reference measures; however, microinstability is frequently diagnosed in those with a lateral centre edge angle > 25°. Other associated imaging findings reported include impingement morphology, anterior labral tearing, femoral head chondral injury, ligamentum teres tears and capsular attenuation.

CONCLUSIONS

The current literature does not provide strong evidence for imaging features diagnostic of microinstability. In the appropriate clinical context, dysplastic morphology, anterior labral tears and ligamentum teres tears may be suggestive of this condition although further research is needed to confirm this.

PROSPERO REGISTRATION

CRD42019122406.

Pre-existing osteoarthritis remains a key feature of arthroscopy patients who convert to total hip arthroplasty

OBJECTIVES

To determine the rate of conversion to total hip arthroplasty following ipsilateral hip arthroscopy by a single surgeon in New Zealand and to describe patient-related and surgical characteristics of patients who converted.

METHODS

A retrospective cohort analysis of hip arthroscopy patients with 2 years of minimum follow-up identified the total hip arthroplasty conversion rate using the New Zealand National Joint Registry. Prospective data collected from patients who subsequently converted to hip arthroplasty included: sex, age at arthroscopy, body mass index, side of hip arthroscopy and arthroplasty, duration of symptoms and patient-reported outcome measures. Imaging (Tönnis grade and lateral centre-edge angle) and surgical findings (labral, ligamentum teres and osteochondral pathology) along with the arthroscopic procedures performed were also documented.

RESULTS

Sixty-six out of 1856 (3.56%) primary hip arthroscopies were followed by an ipsilateral hip arthroplasty during the follow-up period (mean 87 ± 29 months). Most patients had pre-existing osteoarthritis and/or chondral lesions (n=51). Dysplasia and over-resection of the acetabulum were also identified as contributing factors.

CONCLUSION

Conversion rate by a high-volume surgeon in New Zealand was relatively low. Most patients had pre-existing osteoarthritis and/or chondral lesions that became apparent at arthroscopy. Dysplasia is also a factor to be cautious of when selecting patients for arthroscopy. Acetabular resection must be approached cautiously.

LEVEL OF EVIDENCE

Level IV.

Safety, feasibility and efficacy of side-alternating vibration therapy on bone and muscle health in children and adolescents with musculoskeletal disorders: A pilot trial

AIMS

A pilot study was performed to establish the safety, feasibility and efficacy of vibration therapy (VT) on bone and muscle health in children and adolescents with a range of musculoskeletal disorders.

METHODS

Seventeen participants (15.7 years ± 2.9 years), with conditions that impacted on their musculoskeletal health, completed 20 weeks of side-alternating VT for 9 min/session, 4 times/week at 20 Hz. Data were collected at baseline and after 20 weeks of intervention. Assessments included whole-body dual-energyX-ray absorptiometry, muscle function (force plate) and 6-min walk test.

RESULTS

Compliance with the prescribed VT training protocol was relatively high overall at 78% and there were no adverse events reported. After 20 weeks intervention, functional assessments showed time taken to perform the chair test was reduced by 15% (P = 0.018), leg balance improved with standard ellipse area decreasing by 88% (P = 0.006) and distance walked in the 6-min walk test improved by 9% (P = 0.002). Participants displayed increased total body mass (1.94 kg; P = 0.018) with increased lean mass (1.20 kg; P = 0.019) but not fat mass (P = 0.19). There was no change in total body bone mineral density (P = 0.44) or bone mineral content (P = 0.07).

CONCLUSIONS

Twenty weeks of side-alternating VT was a feasible protocol that was associated with improvements in physical function and no detrimental effects on lean mass, bone mass or density in children and adolescents with musculoskeletal disorders.