ABSTRACT
Objective To investigate the reliability of using the pubic symphysis diastasis of 25 mm and anterior separation distance of sacroiliac joint to differentiate anteroposterior compression (APC) type Ⅰ and Ⅱ injuries as well as assess the injury severity.Methods A total of 11 (seven males and four females) fresh cadaver specimens with 22 hemipelvis were collected.The pelvic APC injury test models including fixed hemipelvis (restricted group) and unfixed hemipelvis (non-restricted group) were established,with 11 hemipelvis in each group according to the random number table method.Meanwhile the specimens were divided into male group (14 hemipelvis) and female group (eight hemipelvis),simulating APC type injury external rotation hemipelvis.The public symophysis interval and anterior interval of sacroiliac joint of the original pelvis,the pubic symphysis diastasis and anterior diastasis of sacroiliac joint after anterior tibiofibular ligament failure,as well as the affected pelvis ligament and sacral ligament injury were recorded and compared between the restricted and non-restricted groups,male and female groups.Results There were no significant differences in the public symphysis interval of the original pelvis and anterior interval of sacroiliac joint between the restricted group and the non-restricted group (P ＞ 0.05).The pubic symphysis interval of the original pelvis was [(5.13 ± 0.61) mm] in male group and (4.03 ± 0.84)mm] in female group (P ＜ 0.05).When the anterior tibiofibular ligament ruptured,the pubic symphysis diastasis distance was (23.36 ± 7.27) mm,ranging from 12 to 41 mm,and the diastasis distance of anterior sacroiliac joint was (9.82 ± 3.25)mm,ranging from 5 to 18 mm.In terms of the public symphysis interval,there were no significant differences between male and female groups,restricted and the non-restricted groups (P ＞ 0.05).In terms of anterior interval of sacroiliac joint,there was significant difference between male and female groups (P ＜ 0.05) but no significant difference between the restricted and non-restricted groups (P ＞ 0.05).In the restricted group,sacrotuberous ligament injuries were found in four patients,and sacrospinous ligament injuries in five,whhile there were no obvious sacrospinous ligament and sacrotuberous ligament injuries in non-restricted group.There were 10 specimens with the pubic symphysis diastasis ≥23.36 mm and 10 specimens with the diastasis distance of anterior sacroiliac joint ≥9.82 mm (46％),and there were 15 specimens with at least the pubic symphysis interval ≥ 23.36 mm or the anterior interval of sacroiliac joint ≥ 9.82 mm (68％).Conclusions The public symphysis interval ≥ 23.36 mm or anterior interval of sacroiliac joint ≥ 9.82 mm can distinguish anteroposterior compression Ⅰ from Ⅱ injuries,and the combination of the two criteria can be beneficial to assessment of pelvic injury severity.
ABSTRACT
Objective To establish a three-dimensional finite element model of pelvic anteroposterior compression (APC) for analysis of mechanisms for related liganentous damages.Methods A finite element model and a laboratory mechanical model of APC were established using the same pelvic specimens.In a finite element model of normal pelvic bones and ligaments,after the right pelvis was fixated the pubic symphysis (PS) was sectioned.Next,a manual external mobile force was gradually applied to the left hemipelvis to make the PS diastasis 10,20,30,40,60,80 and 100 mm apart.The mechanical experiment revealed the anterior sacroiliac ligament (ASIL) was ruptured when the PS diastasis reached 28 mm.After the strain value of ASIL was calculated through the finite element model,it was applied to the other pelvic ligaments.The displacement in front of the sacroiliac joint (SIJ),stress,strain and extent of injury and disruption of sacrotuberous/sacrospinous ligaments (STL/SSL) with a corresponding PS diastasis were observed and recorded.Results ASIL failed at the point when the PS diastasis was 28 mm and the displacement in front of SIJ was 7.41 ± 1.14 mm.The strain and maximum principal stress of ASIL calculated in the finite element model were 259.5％ and 543.24 MPa respectively.The maximum principal stress value of SSL was 35.00 MPa at the point of failure when the PS diastasis and the displacement in front of SIJ were 51 mm and 15.23 ±2.88 mm,respectively.When the PS diastasis and the displacement in front of SIJ were 100 mm and 7.5 mm respectively,the maximum principal stress value of STL was 16.17 MPa but the strained ligament was not ruptured.When the pelvis was rotated externally step by step,the ASIL failure was followed by the rupture of SSL but not necessarily by the STL failure.Conclusion As the finite element pelvic bone-ligament model established in this study can effectively simulate the mechanisms for APC injury,it can be used to evaluate different extents of pelvic ligamentous injury,providing a basis for the biomechanical study of pelvic bones and ligaments.
ABSTRACT
Objective To analyze features of the lateral leg peroneal artery perforator free flap,and study the clinical application of free peroneal artery perforator flap transplantation for repairing forefoot defects.Methods Retrospectively analyzed 9 patients with forefoot defects which had been repaired with free lateral leg peroneal artery perforator flap transplantation.In this group,the skin and soft tissue defects size were 4.5 cm ×4.0 cm-13.5 cm × 6.5 cm,Focused on analyzing the features of forefoot skin and soft tissue defects,the design and harvesting of lateral leg peroneal artery perforator flap,and vascular anastomosis and vessel matching,meanwhile,follow-up the survival condition and appearance of the flap,the function of foot and ankle after operation.Results In the 9 cases,the larger myocutaneous perforator arising from peroneal artery,accompanying 2 vena comitans,were found slightly above the midpoint of the line between fibula head and lateral malleolus in lateral leg.The flaps transfered to repair forefoot defects,artery end-end anastomosis:in 5 cases cutaneous branch of peroneal artery to dorsal artery of foot,in 4 cases by cutaneous branch of peroneal artery to dorsal metatarsal artery;vein end-end anastomosis:in 1 case 2 accompanying veins of peroneal artery cutaneous branch to 2 accompanying veins of dorsal artery of foot,in 5 cases 1 accompanying vein of peroneal artery cutaneous branch to 1 accompanying vein of dorsal artery of foot or metatarsal,in 3 cases 1 accompanying vein of peroneal artery cutaneous branch to 1 accompanying vein of dorsal artery of foot or metatarsal,simultaneously,the another accompanying vein of peroneal artery cutaneous branch to 1 dorsal superficial vein of the foot.All the 9 flaps survived,and no vessel articulo happened.The venous return of flaps had no significant difference between repairing 1 vein and 2 veins in gross appearance.All wounds healed in one-period.Followed-up 2-6 months postoperative,1 patient was performed flap reshaping due to flap fat and clumsy at 5 months postoperative,others,the skin texture and appearance of the flaps were good and satisfactive.Conclusion Free transplantation of the lateral leg peroneal artery perforator flap broke away from the bondage of pedicled flap,had more freedom in flap design,and effectively controlled the trauma of donor and recipient site.The flap have the merits,blood vessel anatomy is relatively stable,blood supply is reliable,harvesting is simple,skin texture is similar to the forefoot and the effect is better,operation of the donor and recipient sites can accomplish under a identical anaesthesia and tourniquet.Thus,the lateral leg peroneal artery perforator free flap is an effective metheod in reparation of the forefoot defects.