Effect of clinician's experience and expertise on the inter- and intra-observer reliability of hip migration index in children with cerebral palsy: A STROBE-compliant retrospective study

Few studies have investigated the reliability of Reimers' hip migration percentage (RMP) in children with cerebral palsy (CP). Most studies on the topic reflected rating results of physician with a similar level of experience from the same expertise. This study aimed to determine the effect of clinician's experience and expertise on the intra-and inter-observer reliability of RMP.In this retrospective observational study, hip radiographs of children with CP were identified. 5 observers with different degrees of working experience from 3 different clinical fields, including orthopedics, radiology, and physical medicine and rehabilitation, performed all RMP measurements. All measurements were repeated 6 weeks later by the same observers. Inter- and intra-observer reliability for RMP measurements were assessed using Intraclass Correlation Coeficient (ICC), calculated from 2 sets of repeated measurements on a subset of 50 hips, with a 6 week apart for each observer.Fifty hip radiographs of 25 children with CP (10 females and 15 males; mean age: 6 years; age range: 2-8 years) were examined in the current study. No significant differences existed in intra-and inter-observer measurements. Excellent intra-observer reliability was observed between the 2 separate measurements for each observer, with a mean ICC of 0.976 (range: 0.956-0.989; P < .001). Among 5 observers, inter-observer reliability was excellent for the 2 separate RMP measurements, with the mean ICC minimally increasing between the 2 measurement periods (mean ICC: 0.928, range: 0.838-0.979 and mean ICC: 0.936, range: 0.861-0.983, respectively) (P < .001).Clinician's experience and expertise may not affect inter-and intra-observer reliability of RMP measurements.

Avascular necrosis in children with cerebral palsy after reconstructive hip surgery

PURPOSE

Progressive hip displacement is one of the most common orthopaedic pathologies in children with cerebral palsy (CP). Reconstructive hip surgery has become the standard treatment of care. Reported avascular necrosis (AVN) rates for hip reconstructive surgery in these patients vary widely in the literature. The purpose of this study is to identify the frequency and associated risk factors of AVN for reconstructive hip procedures.

METHODS

A retrospective analysis was performed of 70 cases of reconstructive hip surgery in 47 children with CP, between 2009 and 2013. All 70 cases involved varus derotation osteotomy (VDRO), with 60% having combined VDRO and pelvic osteotomies (PO), and 21% requiring open reductions. Mean age at time of surgery was 8.82 years and 90% of patients were Gross Motor Function Classification System (GMFCS) 4 and 5. Radiographic dysplasia parameters were analysed at selected intervals, to a minimum of one year post-operatively. Severity of AVN was classified by Kruczynski's method. Bivar- iate statistical analysis was conducted using Chi-square test and Student's t-test.

RESULTS

There were 19 (27%) noted cases of AVN, all radio- graphically identifiable within the first post-operative year. The majority of AVN cases (63%) were mild to moderate in severity. Pre-operative migration percentage (MP) (p = 0.0009) and post-operative change in MP (p = 0.002) were the most significant predictors of AVN. Other risk factors were: GMFCS level (p = 0.031), post-operative change in NSA (p = 0.02) and concomitant adductor tenotomy (0.028).

CONCLUSION

AVN was observed in 27% of patients. Severity of displacement correlates directly with AVN risk and we suggest that hip reconstruction, specifically VDRO, be performed early in the 'hip at risk' group to avoid this complication.

Utility of combined hip abduction angle for hip surveillance in children with cerebral palsy

BACKGROUND

Spontaneous hip lateralization complicates the management of non-ambulatory children with cerebral palsy (CP). It can be diagnosed early using radiographs, but it involves standardization of positioning and exposure to radiation. Hence, the aim of this study was to assess the utility of Combined hip abduction angle (CHAA) in the clinical setting to identify those children with CP who were at greater risk to develop spontaneous progressive hip lateralization.

MATERIALS AND METHODS

One hundred and three children (206 hips) with CP formed our study population. There were 48 boys and 55 girls aged 2-11 years (mean 5.03 years). 61 children were Gross Motor Function Classification System (GMFCS) level 5, while 42 were GMFCS level 4. Clinical measurements of CHAA were statistically correlated with radiographic measurements of Reimer's migration percentage (MP) for bivariate associations using χ(2) and t tests.

RESULTS

CHAA is evaluated against MP which is considered as a reliable measure of hip subluxation. Thus, for CHAA, sensitivity was 74.07% and specificity was 67.35%. False-positive rate was 32.65% and false-negative rate was 25.93%.

CONCLUSIONS

Our study shows that correlation exists between CHAA and MP, which has been proved to be useful for hip screening in CP children at risk of hip dislocation. CHAA is an easy, rapid, cost-effective clinical test which can be performed by paraclinical health practitioners (physiotherapists) and orthopedic surgeons.