HABITUAL HIP DISLOCATION IN CHILDREN WITH TRISOMY 21 - SURGICAL TREATMENT WITH A PROXIMAL FEMORAL VARUS DEROTATION OSTEOTOMY
Bibliographic record
Abstract
Background Habitual hip subluxation and dislocation is a potentially disabling feature of Trisomy 21. We describe long-term outcomes following precise use of the femoral varus derotation osteotomy to achieve and maintain hip stability and community ambulation. Methods All individuals with Trisomy 21, who had hip surgery at Toronto9s Hospital for Sick Children between 1998 and 2008, were searched using the hospital databases. 16 hips in 9 children aged less than 10 years, were identified. All had a femoral varus derotation osteotomy (VDRO) with a target femoral neck shaft angle (NSA) of 105° and less than 20° external rotation. All were performed by the senior author JHW. The clinical notes and radiographs were reviewed from presentation to final follow up. Continuous variables were assessed for normality with the d9Agostino Pearson test. Normally distributed variables are presented as means with 95% confidence intervals. Pre and postoperative means were compared using the student9s t-test for paired samples. Results Mean age at first known hip dislocation was 4.56 years (3.98, 5.15), mean age at surgery 6.07 years (5.15, 7.0) and mean follow-up 5.4 years (3.75, 7.06). Mean femoral neck shaft angle (NSA) fell from 166.7° (162.2°, 171.1°) to 106.0° (103.1°, 110.2°). In 2 hips, significant intraoperative instability persisted and periacetabular osteotomies with capsulorraphies were required. All patients developed an asymptomatic waddling gait postoperatively. 14 hips developed peritrochanteric varus deformities, mean 20.7° (15.96°, 25.4°)2 (12.5%) sustained periprosthetic fractures 4 and 8 years postoperatively. 1 hip (6.2%) developed painful arthritis. None re-dislocated at latest follow up. Conclusion Prevention of long term disabling pain from habitually dislocating or recurrently subluxed hips, in patients with Trisomy 21, requires surgical intervention to increase hip containment. We believe surgical management of habitually subluxed or dislocated Trisomy 21 hips allows for a predictable result. We recommend a varus producing proximal femoral osteotomy to correct the NSA to 105° with less than 20° of external rotation. This technique was successful at restoring and maintaining hip stability in 16 hips with a mean follow-up of 5.4 years, whilst maintaining the patient9s ability to remain community ambulators. It should be performed before aged 8 or signs of a widened or V-shape teardrop develops. In our experience this has been effective in maintaining hip stability. However, little is known about the natural history of habitual hip dislocation in these children. Patients with Trisomy 21 are living longer with hips that are at continuous risk. Thought should be given to the potential benefits of periodic screening of this treatable hip condition.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".