Platelet to lymphocyte ratio was a risk factor in Perthes disease.

The study was aimed to determine the relationship between PLR (platelet to lymphocyte ratio) and the lateral pillar classification of Perthes disease, and to provide an alternative index for clinical diagnosis. In addition, the association of the PLR with the necrosis stage of Perthes disease was also explored. This was a retrospective study. 74 children with Perthes disease and 60 children in the healthy control group without femoral head necrosis in our hospital from 2012 to 2021 were collected. The general data and clinical parameters were collected from the hospital information system. The modified herring lateral pillar classification was collected for the fragmentation stage case group and the PLR, NLR (neutrophil to lymphocyte ratio), LMR (lymphocyte to monocyte ratio) and PNR (platelet to neutrophil ratio) were calculated. The cases were divided into four groups, herring A and B were group I, herring B/C and C were group II, the healthy control group was group III, and the necrosis stage was group IV. The hematological indexes (NLR, PLR, LMR, PNR) of children at different stages were statistically analyzed. Group I consisted of 36 patients, with an average age of 7.4 ± 2.0 years (3-11 years). Group II consisted of 23 patients, with an average age of 7.4 ± 1.9 years (4-12 years). Group III consisted of 60 patients, with a mean age of 7.4 ± 2.7 years (4-13 years). Group IV consisted of 15 patients, with an average age of 6.4 ± 1.7 years (3-10 years). The average values of PLR in groups I, II, III and IV were 131.98 ± 47.44, 122.19 ± 37.88, 102.46 ± 30.68 and 128.90 ± 28.11, respectively. It's worth noting that there was statistically significant difference among groups I, II and III (P = 0.003). The optimal threshold of PLR was 130.25, the sensitivity was 45.8% and the specificity was 85%. PLR was also significantly different between groups III and group IV. PLR was higher in Herring A and B classifications than in Herring B/C and C classifications. PLR had certain diagnostic value in both the necrosis stage and fragmentation stage as a risk factor.