Predictivity of International Hip Dysplasia Institute classification in Pavlik harness treatment and correlation with Graf ultrasonographic classification

Incidence and risk factors for persistent acetabular dysplasia in patients with developmental dislocation of the hip treated by Pavlik Harness

Some patients with developmental dysplasia of the hip (DDH) before 6 months of age successfully treated by Pavlik Harness (PH) still had persistent acetabular dysplasia (PAD). This study aimed to investigate the incidence and risk factors for PAD in patients with DDH treated by PH. We retrospectively reviewed the data of 89 patients (109 hips; mean age, 3.2 ± 1.5 months) with DDH treated by PH. Prior to treatment, all patients underwent ultrasound examination and classified according to Graf's method. PH was terminated once the hip achieved imaging recovery criteria. At final follow-up, the acetabular index (AI), center-edge angle (CEA) of Wiberg were measured on radiograph. Overall, 67/109 hips (61.5%) had successful PH treatment. Among these 67 hips, 58 hips (86.6%) achieved satisfactory outcome, nine (13.4%) had PAD. Age of the patients with PAD (4.3 ± 1 months) was significantly higher than those without PAD (2.8 ± 1.5 months) ( P = 0.001). Hips with PAD had higher mean Graf grade than those with satisfactory outcome ( P = 0.014). Logistic regression-confirmed age and Graf classification were risk factors for PAD. Overall, 55/67 (82.1%) met imaging recovery criteria to stop PH treatment, whereas 12/67 hips (17.9%) did not. The rate of PAD at final follow-up in patients achieving recovery criteria (4/55; 7.3%) was significantly lower than those not achieving it (41.7%) ( P = 0.007). In conclusion, age and Graf classification are risk factors for PAD. If hips are not normal at the end of PH treatment, the risk of PAD increases further.

Morphological Development of the Hip in Normal Infants Under Six Months of Age by the Graf Ultrasound Method

OBJECTIVE

This large-sample observational study aims to analyze the morphological development of the hip joint in Chinese normal infants under 6 months of age by the Graf ultrasound method.

METHODS

The clinical and ultrasound data of infants who underwent early screening for developmental dysplasia of the hip (DDH) in the authors' clinic from January 2011 to December 2019 were analyzed retrospectively. The standard Graf method was used to measure the hip joint α angle, β angle and femoral head coverage (FHC). The infants with Graf type I or IIa hips were included in this study. All infants were grouped by age. FHC, α and β angles were compared among different study groups.

RESULTS

A total of 3,067 infants (6,134 hips) were included in the study. There were 1,164 males and 1,903 females with an average age of 77 days (1-180 days). The mean α angle was 62.4 ± 3.6° on the left and 63.2 ± 3.5° on the right (P < 0.001). The mean β angle was 55.6 ± 4.5° on the left and 54.8 ± 4.5° on the right (P < 0.001). The average FHC was 54.2 ± 4.6% and 54.8 ± 4.2%, accordingly (P < 0.001). The α angle and FHC of females was significantly smaller than that of males (P < 0.001). While the left β angle in females was slightly larger than males (P = 0.014), there were no significant differences in the right β angle between the two sexes (P = 0.150). During the first 3 postnatal months, the α angle and FHC increased while β angle decreased with age. However, the α and β angles and FHC were stable at a relatively constant level from the 4 to the 6^th postnatal month.

CONCLUSIONS

The normal infant hip reveals progressive maturation during the first 3 months after birth, and then enters a plateau period during the 4 to 6^th month. The development of hip joint in females and of the left side slightly lags behind that in males and of the right side, which is consistent with the observation that DDH is more common in females and on the left hips.