Background Partial rotator cuff tears result in pain and disfunction in patients.An previous study,the researchers measured the supraspinatus tendon of 17 corpses and came to a conclusion that the average thickness of the supraspinatus tendon was 12 mm.Divides the rotator cuff tears into partial articular tears,partial bursa tears and intra-tendon tears according to the injury sites.Based on the thickness of injured rotator cuff measured during the operation,the tears are divided into 3 degrees:Degree I (≤3 mm),Degree Ⅱ (3-6 mm) and Degree Ⅲ (≥ 6 mm),and the injured thickness of the Degree Ⅲ is more than 50%.Waibl et al put forward the concept of partial articular surface tendon avulsions(PASTA) and the trans-tendon approach to repair the injury.The PASTA has a high morbidity.Modi et al reviewed 100 cases who were all over 35 years old.They recieved an arthroscopic surgery for rotator cuff lesions.Waibl then found 62 cases had PASTA.Yamanaka et al followed 40 PASTA patients using arthrography,the average follow-up was 412 days.They found that the PASTA had a tendency to expand (53%) and to progress to full-thickness tears (28%).Take this into account,most scholars tend to endorse the decision that tears over degree Ⅲ must be repaired.The methods include the conventional repair after the conversion of the full-thickness tear and the direct repair of the tears using the tendon approach.Compared with the former,the tendon repair can save the residual normal rotator cuff tissue,and the length-tension balance after rotator cuff repair is simmilar to normal anatomy.Up to now,China is still lack of treatment reports for such reported injuries.From March 2008 to July 2010,we had 12 cases of patients with PASTA who recieved the arthroscopic trans-tendon repair using the method improved by Lo.All patients were followed up for 12 months or more,and the results are as follows.Methods I.General Information:There are 12 cases in the group,including 5 males,7 females,whose ages are from 29 to 72 years old with the average age of 52.9±13.3 years old.9 lesions were on the right shoulder,3 on the left shoulder,and nine on the dominant shoulder.6 patients had a history of trauma on their shoulders,of which 3 patients hit their shoulders on the ground and 3 hit their hands on the ground.All patients have a pain of the injured shoulder,night pain and most had a problem of shoulder mobility.The patients received the preoperative functional exercise,physical therapy,non-steroidal anti-inflammatory drug therapy and local steroid injection for 1 to 17 months (average 6 months).Physical examination was as follows:11 cases had front shoulder lateral tenderness,9 cases had positive Neer impingement signs,9 cases had positive Hawkins impingement signs,7 cases had positive signs of painful arc from 60 to 120 °,and the Jobe tests of 9 cases were positive.The preoperative MRIs of all the patients showed a rotator cuff tear.Surgical methods:After general anesthesia,the patient was placed in the lateral position with little abduction and anteflexion traction.After sterilization and drape,we marked the bony landmarks and the position of the surgery approach in the skin.Build a rear channel at the first step of surgery.Then we made a arthroscopic examination of the glenohumeral joint.Then build a front channel from outside to the front and examine the glenohumeral joint.Use the planer and radio frequency to repair and clear the damage at the end point of the supraspinatus muscle.Assess the extent of the damage of the joint side rotator cuff,and if the damage was up to 6 mm in width which means Ellman degree Ⅲ PASTA lesion,the damage needed to be repaired (Figure 1A).Before the repair,we must take a subacromial decompression.Insert the arthroscope into the subacromial bursa using the same rear incision.Remove and clean the bursa tissue through the front and the lateral channel until the rotator cuff footprints besides the bursa could be exposed clearly and completely.Then the shoulder acromialplasty could be done.The next step was to examine if there is rotator cuff injuries by synovial side.If the residual end point of rotator cuff becomes thin or obvious degeneration or bursa side damage exists,clean up and make it become full-thickness tear,and then repair the damage.If the lateral rotator cuff end point was still healthy and there is no damage of the bursa side,we would do the trans-tendon repair.Insert the Arthroscope into the glenohumeral joint again through the rear entrance,adjust and lock the position of PASTA lesion,polish the greater tuberosity of the rotator cuff using the burr to make the inner side rotator cuff footprints fresh,and use a NO.18 spinal needle to get close to the outer edge of the acromion to insert into the supraspinatus tendon till the glenohumeral joint.Then ensure the position and direction of the rivet.Puncture the skin and tendons with a small sharp knife parallel to the direction of the needle,make sure the direction and the needle insert position,remove the needle,and insert a 5.0 mm rivet or 23.5 mm rivets according to the anteroposterior dimension of rotator cuff injury (Figure 1B).The rivet should be close to the humeral head cartilage tightly and made a 45 ° angle with the major tubercle surface.The rivets should be placed in the anteroposterior direction and located in the front and posterior edges.Insert the healthy tissue in the inner rim of the injured supraspinatus tendon by a beak-like thread,and then haul the thread out retrograde.The distance of the threads must be at least 10 mm to ensure that there was a bridge enough to fix the rotator cuff footprint.Spinal needle could also be used.First we should haul the latter thread of the two threads in the rivets with different colors through the front approach.Then puncture the healthy tissue of the inner rim of the injured supraspinatus tendon and haul the puncture needle out in the latter direction.If the position was good,the PDS thread was inserted out through the front approach.Using as the direct thread,the latter of the threads was inserted into the supraspinatus tendon retrograde.Then the thread punctured the inner rim of supraspinatus from the behind to the front with other threads.If the anteroposterior dimension of the injured tissue was less than 2 cm,two threads with different colors could go through the channel at the same time (Figure 1C).If the residue injured tendon in the joint side was found retraction,grip pliers should be inserted into the glenohumeral joint through the latter approach to grip the residue tendon for the reduction during the surgery.The assistant hold the grip pliers continuously to maintain the reduction,and then the surgeon accomplished the sutures.If there were two rivets used and when the sutures were accomplished,we should make a fixed knot (Figure 1D).Insert the arthroscope into the subacromial gap again and fix the threads with the same color using the SMC knot separately.Insert the arthroscope into the glenohumeral joint to assess the rebuilding of the rotator cuff footprint,and at this time the rotator cuff footprints was close to the humeral head cartilage (Figure 1E).Postoperative rehabilitation:The shoulder joint should be fixed in the little abduction position with a strap postoperatively for 4 weeks.The pendulum motion,Godman movement,passive external rotation exercises,elbow flexion and extension exercises should proceed early after the surgery.Avoid the shoulder up over the head for 4 weeks.After 4 weeks,the strap could be removed and patients should do the stretching exercises over the head and stretching exercises in the shoulder rotation.Take isometric exercises 10 weeks after the surgery.Efficacy evaluation:Here we use the american shoulder and elbow surgeons(ASES) scoring criteria and the university of california at los angeles(UCLA) scoring criteria.ASES score was calculated as follows:we got a visual analog scale(VAS) from a survey of patients in pain scores and cumulative activity of daily living score(ADL),after the calculation make each accounted for 50% of the weight.The pain score=(10－VAS score)×5,function score = ADL score÷3×5,which means that the pain and function scores account 50 points each,and add the total score of 100 points.UCLA score criteria total score is 35 points,including the pain score of 10 points,the function score of 10 points,the joint flexion angle score of 5 points,the flexion strength score of 5 points and the patient satisfaction of 5 points.34 to 35 points are considered as excellent,28 to 33 as good,21 to 27 as basically qualified,and 0 to 20 as poor.Results 12 cases of patients had the PASTA receive rotator cuff trans-tendon repair.Among them,there are 5 males and 7 females,and all of them had an Ellman degree Ⅲ tear.The patients were followed up from 12 to 36 months and the average follow-up period was (22±7.3) months.ASES score:follow-up score (89.7±5.6) points,significantly improved compared with the preoperative points (49.8±9.8)(t=12.25,P<0.0001).The follow-up UCLA score of (30.4±3.2) points improved significantly from the preoperative points of (17.3±3.3).The excellent rate was 91.7%.Discussion The principles of the joint side rotator cuff injury:The procedure for the joint lateral rotator cuff injury during the arthroscopic surgery includes:(1) clean up the rotator cuff with or without the subacromial decompression;(2) step 1 with the intra-tendon repair;(3) step 1 with the repair when the damage becomes into a complete tear.Despite earlier reports concluded that the simple clean of the rotator cuff with the subacromial decompression could relieve the pain and improve the function in patients,recent studies suggest cleaning and decompression cannot prevent the partial rotator cuff tear and damage to become a complete tear and symptoms to be worsen.Kartus et al found that 34.6% of the partial tear patients became a complete tear after a cleaning up of the rotator cuff with the subacromial decompression.And their pain and function scores were significantly less than the patients without a complete tear.By contrast,the rotator cuff repair obtains a more reliable effect,and prevents the progress of the rotator cuff tear.Evidence-based medicine shows that when tear is not more than 50%,the simply debridement of the rotator cuff with the subacromial decompression can achieve satisfactory results.But when the tear is not less than 50%,only the repair will be able to obtain satisfactory results.The traditional way which turns the damage into a complete tear has a direct and convenient advantage,and achieved good clinical results,but it is difficult to remodel the connection of fibrocartilage and has a high re-tear rate,for there is only scar healing in its bone-tendon junction.Thus,recently,many scholars have started to explore the trans-tendon approach to keep the bursa side with intact footprints.Studies have shown that the trans-tendon approach is able to improve the healing rates of the rotator cuff repair.Improvement and experience of the Lo intra-tendon repair technique:According to the technique reported by Lo et al,we can use one or two 5.0 mm medial rivets to fix the medial supraspinatus footprint.When using two rivets,make the double pulley to form a horizontal double suture bridge on the surface of the medial supraspinatus footprint to fix the footprint strongly.The advantages of this technique are as follows:(1) the fixation of the suture bridge to the rotator cuff footprint has biomechanical advantages;(2) the double pulley technique reduces the frequency of threading,facilitating the surgical procedure and shortening the operation time.The disadvantages of this technique are as follows:(1) the bare footprints of PASTA only allow one rivet.If we use two rivets,there is a risk of overload;(2) the double pulley technique needs the sixth finger knot pusher which is not introduced to china,and there is a risk of loose knot using the ordinary knot pusher;(3) for some PASTA cases with serious retracting of the residual tissue,the puncture needle should be inserted bias the medial side using the Lo technology.It results in the high tension of the posterior repaired rotator cuff,the synovial tissue bulge and the tendon balance loss,which increase the postoperative pain.Our improvement is as follows:(1) a 5.0 rivet with two strands is recommended;(2) two strands can be inserted at once or several times according to the injured width,and two strands are fixed with a slip knot.We think that it reduces the risk of overload of the major tubercle and loose knot,and reduces the cost of patients;(3) after implantation of rivets and before the rotator cuff repair,we can use a grasping grip pliers to grip the retraction residual rotator cuff on the joint side and help to reset the major tubercle footprint.At the same time,the spinal needle is inserted intra-tendon and repair with the strand,thus the synovial tissue bulge and tendon balance loss after the suture would be avoided.Conclusions In summary,for more than 50% PASTA patients,the trans-tendon repair in situ technique can maximumly preserve the normal tissue of the rotator cuff,reconstruct rotator cuff footprint anatomically and have a stable fixed tendon-bone interface.The Lo trans-tendon fixation in situ technology can also receive an ideal therapeutic effect when improved appropriately.