Our study showed that MPV can be a predictive value for AVN for DDH patients who were treated with closed reduction and hip spica casting. Especially, at the early postoperative period, MPV increasing was significant.
Several studies have been tried to determinepredictive values in an effort to predict the severity of AVN or growth disturbance 5. These studies have cited various possible risk factors of AVN, including age, gender, laterality, absence of proximal femoral ossific nucleus, use ofpre-reduction traction, preliminary/history of hip abduction bracing, adductor tenotomy, and hip abduction angle incast 7,11-16. AVN is still the main concern following the treatment of DDH by closed reduction and cast immobilization. The reported rate of AVN ranges from 0 to 67%. Brougham et al. 15 reported on 184 patients who underwent closed reduction of 210 hip dislocations and noted AVN in 99 (of 210 affected hips, 47%). In the studies of Herold et al. (450 hips) 17, Gregosiewicz et al. (1211 hips) 18 and Kruczynskiet al. (823 hips) 19, the reported incidences of AVN were12, 21, and 14%, respectively, and the mean AVN rate ofthese studies was 17%. In our study AVN rate was found %18.6. Risk of AVN was unaffected by age, gender, laterality, previous use of hip abduction orthosis, or adductor tenotomy 15,19,21.
There is no study in the literature including relationship between femoral head AVN and MPV. Increase of platelet count and activation may be important on hypercoagulopathy. 16 Any inflammatory stress generation during closed reduction and hip spica casting can trigger coagulobility. The increase in MPV was related to an increase in pro-inflammatory cytokine levels. TNF-α and IL-6 are the cytokines that cause osteonecrosis, and they are linked with enhanced oxidative stress, which contributes to platelet activation 20. This pathogenesis may explain the increase of MPV in the early postoperative period. MPV levels increased in all AVN patients. According to us, this finding is very important to explain the relation of MPV with AVN.
The most important limitations of our study are its retrospective natüre and small sample size.
In conclusion, MPV can be considered as a predictive parameter for avascular necrosis in patients with DDH who treated with closed reduction and spica cast. Checking the MPV levels in early postoperative period close follow-up can be an indicator for developing AVN.