Background Clinically,acromioclavicular dislocation is a common disease.Whether surgical treatment should be taken or not depends on the type and degree of the injury,as well as the symptoms,ages,occupation,exercise requirements,and other factors of patients.Acromioclavicular dislocation can be classified as six types (degrees) according to Rockwood.The injury with obvious symptoms above Ⅲ degree is generally considered as an important operation indication.The key point in the surgical treatment of acromioclavicular dislocation is to select appropriate methods for the acromioclavicular joint fixation after reduction.There are many choices of the internal fixation to fix the acromioclavicular joint,such as the Kirschner wire and tension band,the clavicular hook plate or anatomical plate for the coracoclavicular joint fixation,and the cannulated screws,steel wires or suture anchors for the coracoclavicular fixation.The selection of these fixations can be combined with debridement of the acromioclavicular joint,the distal clavicle resection,or stitching and reconstruction of the coracoclavicular ligament.Most of these surgical procedures have obtained better results.However,the internal fixation failure,displacement or dislocation after the fixation removal sometimes happened.Considering that the coracoclavicular ligament plays an important role for the acromioclavicular joint stability,researchers has gradually paid more attentions to the reconstruction of the coracoclavicular ligament recently.The repair methods include the direct suture,the partial ligament displacement,the autologous tendon graft,and the tendon graft transplantation.We chose a simple,less traumatic method for the acromioclavicular dislocations,which is autogenous palmaris longus muscle transplant combined with the suture anchor fixation,and achieved satisfactory results.Methods (1)General information:A total of 30 cases aged from 17 to 55 years (mean 31 years) with acromioclavicular dislocations of Rockwood type Ⅲ,Ⅳ or Ⅴ were collected in our study,including 18 cases of type Ⅲ,1 case of typeⅣ and 11 cases of type Ⅴ.Among all the 30 cases,23 are males and 7 are females,and 20 cases with the right sides and 10 cases with the left sides.All patients suffered an acromioclavicular dislocation without fracture and neurovascular injury,28 cases of which got injured due to the traffic accident and 2 cases owing to hitting.All patients had fresh injuries,and as well as the symptoms of acromioclavicular joint pain,deformity,limited mobility and floating feelings when treated.Preoperative X-rays or MRIs were performed to make the diagnosis that all the patients had a complete acromioclavicular dislocation.The mean time of the operation was 8.2 d (3-20 d) after injury.(2)Surgical methods:General anesthesia was performed using tracheal cannula.Patients lied on the beach chairs in a supine position and turned their head to the healthy side,and the suffering shoulder was blocked up.Make 4 cm longitudinal incision along the coracoid,cut the skin and the subcutaneous tissue,reveal the acromioclavicular joint,the coracoid and mid-distal of the collarbone,remove the intra-articular cartilage fracture fragments and soft tissues before reduction and resect the partial distal clavicle if necessary according to the injury (excision of about 5 mm).Stop bleeding and cover the wound temporarily after the confirmation of the inability to suture the coracoclavicular ligament rupture.(1)The palmaris longus muscle cut:touch the palmaris longus at the center of the wrist in the ipsilateral upper extremity,and make a longitudinal incision from 1 to 1.5 cm at the wrist,and then the palmaris longus is exposed and separated proximally along the subcutaneous.Make another 1 cm longitudinal incision on the predetermined cutting position of the tendon of the proximal muscles in the upper arm,and cut and extract the palmaris longus.The tendon can be folded 2-3 folds back according to its length.(2)The coracoclavicular ligament reconstruction:make two bone tunnels at the ligament remnants of the distal clavicle,and ensure that the distance of these two bone tunnels is at least 1 cm to prevent fractures.Screw a suture anchor with diameters of 5.0 mm on both sides of the coronoid process.Make the prepared palmaris longus bypass the beneath of the coracoid process,pierce the two ends of the palmaris longus together with suture anchors along the bone tunnel of the clavicle,and carry out the tendon suture and suture knot above the clavicle.When tightening the knot,pay attention to the exert pressure above the clavicle to make a full reset of the acromioclavicular joint.After the satisfactory reduction of acromioclavicular joint through X-ray fluoroscopy,wash and suture the wound.The mean operative time was 65 min (40-90 min),and the mean intraoperative blood loss was 70 ml (50-100 ml).(3)Postoperative treatment:After the operation,hang the limb using the neck wrist strap for two weeks.Guide patients to do the shoulder passive functional exercise after the relief of the wound pain.Begin active functional exercise at 6 weeks after the operation.The patients should be reviewed with both X-ray and functional evaluation at one week,one month,3 months,6 months and 12 months postoperatively.(4)Efficacy assessment:Record the average operative time and the blood loss of patients.Make the efficacy assessment according to the X-ray examination of the joint reset condition and the Rockwood shoulder function assessment score.Results The patients in this study were followed up for 12 to 22 months (mean 16 months).The appearances of all patients were improved without the local uplift and swelling.According to the Rockwood shoulder score,25 cases got excellent function and 4 good,1 basically qualified.None case had poor result.The excellent and good rate was 96.7%.All patients had no infection.The cromioclavicular joint subluxation without abnormal appearance occurred in two cases observed through X-ray 3 months after the operation,and two patients had no exacerbated dislocation according to the X-ray examination at 1 year after the operation.Conclusions The acromioclavicular joint dislocation is common in the clinic.There are many treatment methods for the acromioclavicular joint dislocation.The coracoclavicular ligament is important to maintain the acromioclavicular stability.Coracoclavicular ligaments are broken in the over Rockwood type Ⅲ degree injuries.The patients may have varying degrees of abnormal appearance,pain,upper limb muscle weakness,external fixation after the conservative treatment.And the conservative treatment requires a long time,which may lead to joint stiffness.So surgical treatment is a better choice for the young and those with over Ⅲ degree injuries who have higher requirements of the upper limb activity.Currently,there are many surgical methods for the acromioclavicular joint dislocations.Acromioclavicular joint fixation methods are clavicular hook plate,anatomical plate,tension band and so on.The clavicle and coracoid fixation methods are screw,anchors with wire,Endobutton and wire bundling.According to reports,most of these methods can achieve better clinical results,but there are more complications,such as the internal fixation loosening,displacement,fracture,impact and so on.In order to reduce the fixation complications,the internal fixation need to be removed as soon as possible after the local soft tissue scar healed.And after the fixation removal,the reports of re-dislocation of the joint are not uncommon.Therefore,the primary suture or coracoclavicular ligament reconstruction,rather than making a scar to heal,is theoretically able to get a better biomechanical stability.The treatment of aromioclavicular dislocations with autogenous palmaris longus muscle transplant combined with fixation by the suture anchor has its advantages:(1) It is convenient and minimally invasive to cut off the palmaris longus,and surgery is only needed to disinfect the ipsilateral upper extremity;(2) As the coracoclavicular ligament graft,the tendon size and length are more appropriate;(3) Compared with the other surgical methods,the palmaris longus muscle transplantation is a better choice for the reattachment point so close to the anatomical location of the ligament reconstruction;(4) With respect to the tendon allograft,the autologous tendon graft does not have better healing and less risk of infection;(5) The functional loss for the supply area is negligible.Disadvantages:(1) The palmaris longus of some patients is agenesis or special small;(2) It is need to pay attention to do the preoperative examination.The suture anchor provides the relative stability and activity of the joint,which prevents excessive shear forces to cause the relaxation of ligament reconstruction before healing,and also provides time for the articular disk and other soft tissue to heal.Compared with the separate ligament reconstruction or suture,the combination with the application of the suture anchor fixation requires only a simple suspension after surgery,as well as make the patients do early functional exercise to avoid joint stiffness.Applications with wire anchors as the fixation material has some advantages:(1) It is easy to use,and did not need a lot of exposure of the operative field and a small fixed space;(2) The suture provides a non-rigid fixation which retains the fretting physiological state of the acromioclavicular joint.The treatment of the over Ⅲ acromioclavicular joint dislocation for the group of patients with suture anchors and autologous palmaris longus transplantation,can combine advantages of the two surgery,minimize the lack of two surgical procedures,and improve the success rate.It has been proved to be an effective surgical method by the clinical follow-up.Moreover,its application is easy,and it has less trama and help joints early return to the normal function.The samples of patients in this study are not much,we need to accumulate a large number of cases and observation in the future.