1. Risk factors for non union 1st MTPJ fusion with the use of a Dorsal Plate
A. Kaye, G. Williams, A.P. Mollloy, C. Butcher, L.W. Mason
University Hospital Aintree
Liverpool

2. Introduction Common problem Common operation
Typical union rates around 90%+
Minimal literature defining risk factors for non-union
AIM: retrospective analysis of risk factors for delayed / non-union
1 in 40 over the age of 50 years

3. Methods Operations between April 2014 to April 2016
At least 6 months post-operative follow up
Union = bridging bone on two radiographic views with no movement or pain on examination. Any doubt  CT confirmed
Operations performed / supervised by three senior foot surgeons
Dorsal approach using the Stryker Anchorage CP plate with dorsal to plantar compression screw through plate

4. Operative technique

5. Methods & Demographic 71 1st MTPJ attempted fusions in 62 patients
Average follow-up 13 months (range, 6-30 months)
Mean age of 61 years (range, years)
9 male and 62 females
Analysis of any risk factors associated with delayed union

6. Results Non union in 7 patients (combined 9.9%)
All smokers united (n = 17)
100% union rate in patients with preoperative HVA <25 degrees
78% union rate if preoperative HVA >25 degrees
33% union rate if postoperative HVA >25 degrees
Age, gender, diabetes, COPD and rheumatoid arthritis did not show significant associations with non-union

7. Standard OA united

8. Rheumatoid non-union with post op >25

9. Mal reduction >25deg 67% 14 <0.001*
RISK FACTOR Nonunion % Relative Risk p value
Mal reduction >25deg 67% <0.001*
Pre op HVA >25deg 21.9% *
Diabetes %
Rheumatoid %
Hypothyroid 40%
Plate breakage 50% *
Smoking
*Fishers exact test

10. Discussion Overall 10% non-union rate is expected from literature
Pre operative hallux valgus or mal reduction causing non union
Fixation method doesn’t address the tension side in transverse plane deformities
We now use a dorsal plate with medial to lateral screw in hallux valgus deformities greater than 25 degrees pre-operative HVA

11. New method of medial to lateral screw

12. Conclusion Non union 7 patients (combined 9.9%)
Union rate 100% if preoperative hallux valgus <25 degrees
Preoperative moderate-severe hallux valgus and under corrected deformity are the most significant risk factors.
This construct does not neutralise transverse plane deformities and supplemental fixation techniques may be needed in severe deformities.
for non-union of 1st MTPJ arthrodesis using dorsal plate fixation.

13. THANK YOU

14. Conflicts of interest: Yes
Mr A Molloy is a consultant for Stryker