Effect of osteoporosis and intervertebral disc degeneration on endplate cartilage injury in rats

Objective:To investigate the effect of osteoporosis and intervertebral disc degeneration on the endplate cartilage injury in rats.Methods:A total of 48 female Sprague Dawley rats(3 months)were randomly divided into Groups A,B,C and D with 12 rats in each group.Osteoporosis and intervertebral disc degeneration composite model,simple degeneration model and simple osteoporosis model were prepared in Groups A,B and C respectively.After modeling,four rats of each group at 12th.18th and 24th week were sacrificed,Intervertebral height of cervical vertebra C6/C7 was measured.Micro-CT was used to image the endplate of cephalic and caudal cartilage at C6/C7 intervertebral disc.Abraded area rate of C6 caudal and C7 cephalic cartilage endplate was calculated,and then C6/C7 intervertebral disc was routinely embedded and sectioned.stained with safranin O to observe histological changes microscopically.Results:At 12,18 and24 weeks,intervertebral disc height of C6/C7 were(0.58±0.09)mm,(0.53±0.04)mm and(0.04±0.06)mm in Group A rats,(0.55±0.05)mm,(0.52±0.07)mm and(0.07±0.05)mm in Group B rats.At 24th week.intervertebral disc height of Group A rats was significantly lower than that of Group B rats(P<0.05);intervertebral disc height of Groups A and B rats at each time point were significantly lower than that of Groups C and D(P<0.05).There was no significantly statistical difference of intervertebral disc height between Groups C and D(P>0.05).At 12 and 18 weeks,the abraded rate of C6 caudal and C7 cephalic cartilage endplate in Group A rats were significantly higher than that in Groups B.C and D rats(P<0.05);the abraded rate in Group B was significantly higher than that in Groups C and D(P>0.05).Microscopic observation of CT showed that ventral defects in C6caudal or C7 cephalic cartilage endplate in Groups A and B appeared after 12 weeks of modeling;obvious cracks were found in front of the C6 and C7 vertebral body,and cartilage defect shown the trend of"repairing"at 18 and 24 weeks after modeling.Conclusions:Intervertebral disc degeneration and osteoporosis can cause damage to the cartilage endplate.Co-existence of these two factors can induce more serious damage to the endplate.which has possitive correlation with intervertebral disc degeneration.Osteoporosis plays a certain role in intervertebral disc degeneration process,and accelerates the degeneration of intervertebral disc in a specific time window.

Influence of volar margin of the lunate fossa fragment fixation on distal radius fracture outcomes:A retrospective series

BACKGROUND Distal radius fractures accompanied by the volar margin of the lunate fossa(VMLF)lesions are often overlooked or inadequately reduced in clinical practice.AIM To investigate the impact of VMLF fragment in distal radius fractures on the stability and function of the wrist joint.METHODS This was a retrospective study of patients with distal radius fractures who underwent surgical treatment between January 2013 and December 2017.The patients were divided into two groups according to whether the VMLF fragments were fixed or not.X-rays and computed tomography were performed before surgery,immediately postoperatively,and at 1,3,and 6 mo to measure the scapholunate angle,radiolunate angle,capitolunate angle,and effective radiolunate flexion(ERLF).The Mayo wrist score and disabilities of the arm,shoulder,and hand(DASH)score were determined at 1 year.RESULTS Thirty-five patients were included.There were 15 males and 20 females.Their mean age was 52.5±14.3(range:19-70)years.There were 38 wrists(17 on the left side,15 on the right,and three bilateral;16 in the fixed group,and 22 in the unfixed group).The interval between trauma and surgery was from 1 h to 1 mo.The incidence of postoperative wrist instability in the unfixed group(86.4%)was higher than in the fixed group(25.0%)(P≤0.001).Ten patients had ERLF>25°in the unfixed group and none in the fixed group(P=0.019).The Mayo wrist score was 94±5.7 in the fixed group and 68±15.1 in the unfixed group(P<0.001).The DASH score was 4.6±2.5 in the fixed group and 28.5±19.5 in the unfixed group(P<0.001).CONCLUSION Injuries of VMLF,even small fractures,might damage the radial-lunar ligament,leading to postoperative wrist instability,sagittal force line imbalance,and poor recovery of wrist joint function.