Automatic Segmentation of the Paediatric Femoral Head.

Developmental dysplasia of the hip (DDH) is a developmental deformity occurring in 0.1-3.4% of infants. Timely surgical intervention can ameliorate the condition in stable hips and reduce future cases of osteoarthritis and total hip replacement. However, current definitions of DDH are subjective, and thus would benefit from a more objective and reliable assessment metric. Since the shape of the femoral head and its congruence with the acetabulum are disrupted by DDH, analysis of the femoral head could potentially play a role in the development of novel objective morphological metric for stable DDH. Therefore, this paper aimed to segment the paediatric femoral head in stable hips from radiographs, which has not been attempted before in the chosen focus age group (1-16 years) where the pelvis and hip joint undergo significant development. Two techniques were compared against a baseline U-Net: data augmentation and region-of-interest (ROI) networks. Four models were developed either without, with just one, or with both techniques. Evaluated using tenfold cross-validation, the U-Net trained with both techniques achieved the best results, with a Dice Similarity Coefficient (DSC) of 0.951±0.037 (mean ± standard deviation, calculated with 720 images). Future work will use this segmentation algorithm to accurately characterise hip joint morphology and estimate the benefit of early surgical intervention in DDH.

Acetabular Revision Using Trabecular Metal Augments for Paprosky Type 3 Defects.

BACKGROUND: Trabecular Metal (TM) augments are one option when reconstructing bone loss during acetabular side revision surgery. METHODS: We studied 38 consecutive patients with Paprosky type 3 defects that were revised using a TM shell and one or more augments over a 6-year period. There were 29 Paprosky type 3A defects and 9 Paprosky type 3B defects. The mean age of the patients at the time of surgery was 68.2 years (range 48-84). The mean length of follow-up was 36 months (range 18-74). RESULTS: The mean preoperative short form 12 health survey improved from 27.7 before operation to 30.1 at the time of final follow-up (P = .001). The mean Western Ontario and McMaster Universities Osteoarthritis Index score improved from 53 preoperatively to a mean of 78.8 at final follow-up (P < .0001). There was evidence of radiographic loosening in 7 of the cup-augment constructs. One patient developed a deep infection requiring re-revision. Two patients required revision for aseptic loosening. CONCLUSION: The use of TM in complex acetabular reconstruction is associated with good outcome in the short to medium term.