Influence of sesamoid position after scarf osteotomy for hallux valgus on patient-reported outcome. A prospective cohor study

Sesamoid correction achieved during the learning curve for Scarf-Akin osteotomy without lateral soft-tissue release: a single-centre prospective observational study

INTRODUCTION

Scarf-Akin osteotomy (with or without lateral soft-tissue release (LSTR)) is commonly performed to treat hallux valgus (HV). An insufficient correction of sesamoids can be a risk factor for early recurrence of the condition. We set out to determine 1) the radiographic correction achieved after Scarf-Akin osteotomy performed without LSTR and 2) the degree of correction of sesamoids obtained during the learning curve of the technique.

MATERIALS AND METHODS

In this prospective single-centre study, the first 25 feet (25 patients, mean age 55.2 years, 14 left) undergone Scarf-Akin osteotomy without LSTR by a single foot and ankle orthopaedic consultant in his first year of activity were enrolled and followed-up at 1-year. On weightbearing standard pre-operative and 1-year follow-up radiographs two independent observers (senior residents) assessed and compared the hallux valgus angle (HVA), 1st and 2nd intermetatarsal Angle (IMA), distal metatarsal articular angle (DMAA) and tibial sesamoid position (SP, according to the Hardy and Clapham system). The inter and intraobserver reliability of measurements along with the correlation between the improvement achieved in different parameters and the number of cases performed were tested. Intra and post-operative complications were compared between the early (first 12) and late learning periods.

RESULTS

The inter and intraobserver agreement for the radiographic parameters investigated was excellent in all cases (ICC always > 0.92). A statistically significant improvement in mean HVA (from 36 ± 9.8 to 16.3 ± 2.8 degrees), mean IMA (from 14.5 ± 2.3 to 9.9 ± 1.5 degrees), mean DMAA (from 19.4 ± 4.4 to 11.4 ± 1.9 degrees) and median SP (from 4 (IQR, 3-6) to 2 (IQR, 1-2) points) was demonstrated in the cohort (p < 0.001 in all cases). There was a strong positive significant correlation between the progression of cases over time and the improvement achieved in terms of SP (R = 0.60, p = 0.003). Conversely, no significant correlation was demonstrated when comparing the improvement obtained in HVA, IMA and DMAA with the number of cases performed (p > 0.05 in all cases). One complication occurred during the first 12 cases (1 transfer metatarsalgia) and 1 during the last 13 (1 intra-operative fracture).

CONCLUSION

In this series, a satisfactory correction of HV after Scarf-Akin osteotomy was obtained without releasing lateral soft-tissues. Beginner surgeons should be aware that restoring sesamoid position may be more challenging as compared to correcting other angles during the first cases.

LEVEL OF EVIDENCE

Level IV, prospective case series.

Automatic Hardy and Clapham's classification of hallux sesamoid position on foot radiographs using deep neural network

BACKGROUND

There is currently no deep neural network (DNN) capable of automatically classifying tibial sesamoid position (TSP) on foot radiographs.

METHODS

A DNN was developed to predict TSP according to the Hardy and Clapham's classification. A total of 1554 foot radiographs were used for model development. The validation of the model was conducted using radiographs obtained from 113 consecutive first-visit patients of our foot and ankle clinic. On these 113 radiographs, TSP was independently classified by three foot and ankle surgeons and the DNN, and their results were compared. The weighted kappa value of TSP between the DNN prediction and the median of the three surgeons (KAI) was calculated.

RESULTS

The KAI was 0.95 (95 %CI: 0.85- 1.00), indicating sufficient consistency between the surgeons and the DNN.

CONCLUSIONS

We have developed a DNN for automated TSP classification that demonstrates sufficient consistency with foot and ankle surgeons.

LEVELS OF EVIDENCE

Level 3 - Retrospective Cohort Study.