Experimental Study On Autologous Osteochondral Transplantation For Recurrent Anterior Shoulder Dislocation

Purposes1.To investigate the early clinical outcomes of arthroscopic autologous osteochondral transplantation for recurrent anterior shoulder dislocation based on clinical studies,and to provide new treatment ideas for patients with <20% glenoid bone loss.2.To explore the mechanism of autologous osteochondral transplantation in repairing recurrent anterior shoulder dislocation in rabbits by overall observation,histological level and imaging examination.Methods1.Clinical study: A retrospective analysis of 17 patients,12 men and 5 women;age 18-55(32.88±12.33)years;12 right shoulders and 5 left shoulders,who attended our hospital for arthroscopic autologous osteochondral transplantation for recurrent anterior shoulder dislocation from January,2019 to December,2020.The Rowe’s rating system for Bankart repair,the Oxford Shoulder Instability Score(OSIS)and the Simple Shoulder Test(SST)were used before surgery,at 6 months after surgery and at the last follow-up.Simple Shoulder Test(SST)was used to assess shoulder function and to record complications before,during and after surgery.2.Animal experiment: 24 male New Zealand White rabbits,weighing(2.5-3.0)kg,were included and randomly divided into control and experimental groups,12 rabbits in each group.A rabbit model of recurrent anterior shoulder dislocation was established.In the experimental group,a cartilage column was taken with a hollow drill in the nonweight-bearing area of the contralateral knee joint and implanted into the glenoid labral defect area of the shoulder joint;in the control group,the incision was sutured layer by layer after modeling.The rabbit glenoid specimens were removed at 6 and 12 weeks postoperatively,respectively,and the glenoid defect was observed as a whole(bone healing and graft fusion at the glenoid labral defect),histological evaluation(HE staining,Masson staining,and Safranin O-fast green staining),and Micro-CT scanning analysis(bone mineral density,bone volume,and bone trabecular thickness).Results1.Clinical studyAll 17 patients in this group were followed up after surgery for 7-25(18.4±5.4)months.The Rowe score increased from(26.2±6.0)preoperatively to(74.4±4.0)and(82.4±3.1)at 6 months postoperatively and at the last follow-up,respectively,and the differences were statistically significant at different time points postoperatively compared with preoperatively(P<0.05);the OSIS score increased from 37.0±3.6before surgery to 47.4±2.6 and 52.7±2.6 at 6 months and the last follow-up after surgery,respectively,and the difference was statistically significant at different time points after surgery compared with that before surgery(P<0.05);the SST score increased from6.8±0.7 preoperatively to 9.8±0.8 and 11.6±2.6 at 6 months postoperatively and at the last follow-up,respectively,with a statistically significant difference at different postoperative time points compared with preoperatively(P<0.05).The differences were statistically significant(P<0.05)when comparing the postoperative time points with the preoperative time points.At the final follow-up,the patients’ lateral external rotation and abduction external rotation mobility were significantly improved compared with those before surgery.No vascular or nerve injury or re-dislocation occurred during the follow-up period.2.Animal experiment(1)Overall observation: a.Rabbit normal shoulder joint: Similar to the human shoulder joint,bony structures such as the humerus,articular pelvis,scapular gland and rostral process are also present in rabbits,but the structure of the rabbit’s shoulder crest is very different from that of humans,and it is a relatively underdeveloped bony structure.The rabbit articular glenoid has a cloverleaf shape,whereas the human articular glenoid is pear-shaped.The glenoid lip of the rabbit glenoid was only distributed on the anterior inferior side,which was different from the human glenoid.b.Six weeks after surgery: The shoulder abduction,posterior extension,internal rotation and external rotation were more limited on the operated side than on the contralateral side in both groups,while internal retraction and forward flexion were not significantly abnormal than on the contralateral side.The incision on the operated side was free of infection and rupture in both groups and showed grade A healing.No subcutaneous tissue adhesions were seen,muscle sutures were not completely absorbed,and scar tissue was visible at the muscle break.In the control group,the bone surface of the anterior inferior glenoid labrum defect was rough,while in the experimental group,the cartilage column transplanted into the articular glenoid had obvious boundaries with the surrounding tissues and had not yet completely fused.c.12 weeks after surgery: the mobility of the shoulder joint on the operated side improved in both groups of animals compared with that at 6 weeks.There was no oozing,redness or swelling of the incision,no adhesions of the subincisional tissues,more scar tissue than before,and most of the surgical sutures were absorbed than before.In the control group,the anterior inferior glenoid labral defect bone surface was significantly smoother than at 6 weeks.In the experimental group,complete fusion of the transplanted cartilage column with the articular glenoid was seen,with blurred peripheral boundaries and hyperplastic tissue on the anterior inferior side.(2)Histological evaluation: a.6 weeks postoperatively: HE staining could observe a smaller number of bone trabeculae in the bone marrow cavity of the control group,with thinner residual bone trabeculae,larger gaps,and fractures,and destruction of the three-dimensional structure of bone trabeculae.In the experimental group,the number of trabeculae in the bone marrow cavity was significantly increased compared with that in the control group,but the trabeculae were generally thinner and the gaps were enlarged.Masson staining of the control group showed a small amount of collagen fiber production and disorganized arrangement.In the experimental group,more collagen fibers were produced than in the control group,and the arrangement was dense.The amount of chondrogenesis in the control group was very small and the area of heterostaining was very limited.b.12 weeks after surgery: HE staining showed that the number of bone trabeculae in the control group was significantly increased and thicker than that at 6 weeks after operation,and some bone trabeculae were connected,showing a three-dimensional structure.There was no significant difference in the number of bone trabeculae between the experimental group and the control group,but the width of bone trabeculae was significantly increased,and a large number of trabecular connections showed a three-dimensional structure.Masson staining showed that the amount of collagen fibers in the experimental group was significantly higher than that in the control group at 6 weeks,and the collagen fibers in the experimental group were more dense,orderly,and more uniform.Safranin-fast green staining showed that the cartilage formation in the control group was more than that at 6 weeks,and the cartilage production in the experimental group was the highest at 12 weeks.(3)Micro-CT scan analysis: The bone mineral density,bone volume and trabecular thickness of glenoid defects in each group showed an upward trend with the extension of time.At the same time point,the bone mineral density,bone volume and trabecular thickness of the autologous osteochondral transplantation group were higher than those of the control group,and the difference was statistically significant(P < 0.05).Conclusions1.Arthroscopic autologous osteochondral transplantation for recurrent anterior shoulder dislocation with glenoid defect <20% can achieve satisfactory early clinical outcome and stability.It is a reliable and effective procedure,and no complications such as knee pain and stiffness were observed during follow-up.2.Arthroscopic autologous osteochondral grafting is an effective procedure for the treatment of recurrent anterior shoulder dislocation with <20% glenoid defect,and no complications such as knee pain and stiffness were observed during the follow-up period.