Purpose

The purpose of this study was to define the incidence of trochlear dysplasia in an infant cohort being screened for developmental dysplasia of the hip (DDH).

Methods

Newborns screened for DDH that were evaluated with ultrasound for the presence of trochlear dysplasia were retrospectively reviewed. The sulcus angle and trochlear depth were measured. Based on previous work, trochlear dysplasia was defined as a sulcus angle of > 159°. Our newborn cohort was then analyzed to identify potential risk factors for trochlear dysplasia.

Results

A total of 383 knees in 196 infants were studied. In total, 52% were referred for breech intrauterine positioning and 21% were ultimately diagnosed with DDH and had treatment initiated with a Pavlik harness. Of the entire cohort, 8% of knees were deemed to have trochlear dysplasia. Breech patients were found to have a flatter sulcus angle than those that were not breech (149.5° (sd 7.2°) versus 147.9° (sd 7.5°); p = 0.028). Similarly, a shallower trochlear depth was identified in breech patients versus non-breech patients (1.6 mm (sd 0.4) versus 1.8 mm (sd 0.4); p = 0.019). Those with trochlear dysplasia (as defined by sulcus angle > 159°) did show a smaller alpha angle (i.e. more dysplastic hip) as compared with those without trochlear dysplasia (59.2° (sd 10.2°) versus 65.9° (sd 7.5°); p < 0.001). Hips with DDH were 2.4-times more likely to have knees with trochlear dysplasia (95% confidence interval 1.1 to 5.3).

Conclusion

Ultrasound screening of newborn knees reveals that trochlear dysplasia is relatively common in breech babies with DDH.

Level of evidence

III.

Purpose

We aimed to determine which variables were associated with persistent symptoms or need for further surgery in patients treated with in situ fixation for stable slipped capital femoral epiphysis. We hypothesized that patients with greater proximal femoral deformity would require revision surgical intervention.

Methods

We prospectively collected data on stable slipped capital femoral epiphysis patients who underwent in situ screw fixation at a single institution. Demographic and radiographic information, as well as patient-reported outcomes, were collected.

Results

Forty-six patients (54 hips) with an average follow-up of 3.5 years (range: 2.0-8.5) and mean pre-op Southwick slip angle of 40.5° ± 19.4° were studied. We observed one complication following the index procedure (2%). Twelve hips (22%) went on to have a secondary procedure 2.7 ± 2.2 years after the index surgery. Severe slips were 14.8× more likely to undergo a secondary procedure than mild and moderate slips (p < 0.001). We found no correlation between slip severity and patient-reported outcomes (p > 0.6). Hips requiring a secondary procedure had significantly lower Hip disability and Osteoarthritis Outcome scores (76.8 ± 18.4) at final follow-up compared to hips that did not require additional surgery (86.8 ± 15.7) (p = 0.042).

Conclusion

With minimum 2-year follow-up, 22% of patients required a secondary surgery. Patient-reported outcomes did not correlate with slip severity, but were found to be significantly higher in slipped capital femoral epiphysis patients that did not require a secondary procedure. Prophylactic treatment of all slip-related cam deformity was not found to be necessary in this prospective cohort. Patients with moderate-to-severe slips may require secondary surgery.

Level of evidence

Level II.