There are some patients who have traumatic anterior shoulder instability due to minor injuries like overhead activities. The purpose of this study was to clarify characteristic features of traumatic anterior shoulder instability due to minor injuries. According to the mechanism of injury in an initial dislocation, 83 shoulders that underwent the stabilizing surgery for traumatic anterior shoulder instability were divided into two groups. Traumatic group included patients who suffered from a fall or a direct injury. Minor injury group included patients who suffered from the other injury like overhead activity. General joint laxity, range of motion and laxity under anesthesia, and intraarticular findings were compared between two groups. The morphology of superior and middle glenohumeral ligaments, Bankart lesion, Hill-Sachs lesion, and partial articular surface tendon avulsion lesion were observed in arthroscopy. Minor injury group consisted of 19 shoulders with 8 males, 11 females and the mean age of 22.5 years. Traumatic group consisted of 64 shoulders with 52 males, 7 females and the mean age of 24.3 years. Female in minor injury group was significantly more than that in traumatic group. There was no difference in general joint laxity and intraarticular findings between two groups. Range of external rotation in injured side in minor injury group was significantly more than that in traumatic group. Inferior laxity in both sides in minor injury group was more than that in traumatic group. In conclusion, the traumatic anterior shoulder instability due to minor injuries might incline to occur the shoulder in female and with inferior laxity of shoulder.

견관절 전방 불안정성에서 관절와 및 상완골 결손이 동반된 경우 적절한 진단과 치료는 치료 결과에 직접적인 영향을 주므로 중요하다. 견관절 불안정성은 정적 및 동적 안정화 구조물의 손상으로 기인하며, 상완골 두감입 골절(Hill-Sachs 병변), 관절와 골절이나 전하방 관절와 가장자리의 소실 등 정상적인 관절의 해부학 구조물을 훼손시키는 골성 이상 소견이 동반되면 경우에 따라 견관절 불안정성에 영향을 끼칠 수 있다. 본 강좌에서는 견관절 전방 불안정성에서 동반된 관절와 및 상완골의 골 결손에 대하여 논하고자 한다.

Glenohumeral ligaments play an important role in stabilizing the shoulder. However, it is impossible to know how they function in vivo during shoulder motion. To help elucidate this stabilizing role, we conducted in vivo three-dimensional kinematics of the normal shoulder joint using a markerless bone-registration technique. Magnetic resonance images of 14 shoulder joints of 7 healthy volunteers were acquired for 7 isometric abduction positions between $0^{\circ}$ and $180^{\circ}$. We then calculated three-dimensional shortest paths between the origin and insertion of each ligament based on anatomical study in each abduction position. At $0^{\circ}$ of abduction, the posterior band of the coracohumeral ligament displayed the maximum length. At $30^{\circ}$ of abduction, the superior glenohumeral ligament displayed the maximum length. At $60^{\circ}$ of abduction, the anterior band of the coracohumeral ligament and the middle glenohumeral ligament displayed the maximum length. At $120^{\circ}$ of abduction, the anterior band of the inferior glenohumeral ligament displayed the maximum length. We think that the maximum length of these results is an important influence on the function of the soft tissue stabilizer.

The purpose of this study was to investigate humeral translation relative to the glenoid invivo during loaded and unloaded shoulder abduction. CT scans of 9 healthy shoulders were acquired and 3D models were created. The subject was positioned in front of a fluoroscope and motions were recorded during active abduction. The subjects performed two trials of holding a 3kg weight and unload. 3D motions were determined using model-based 3D-to-2D registration to obtain 6 degrees of freedom kinematics. Glenohumeral translation was determined by finding the location on the humeral head with the smallest separation from the glenoid. Humeral translation was referenced to the glenoid center in the superior/inferior direction. The humerus moved an average of 2 mm, from inferior to central on the glenoid, during arm abduction for both conditions. The humeral head was centered within 1mm from the glenoid center above $70^{\circ}$. There were no statistically significant differences for both conditions. The standard deviation decreased gradually over the motion, with significantly lower variability at the end of abduction compared to the initial unloaded position. We assumed that the humeral translation to the center of the glenoid provides maximum joint congruency for optimal shoulder function and joint longevity. We believe this information will lead to better strategies to prevent shoulder injuries, enhance rehabilitation, and improve surgical treatments.

The purpose of this study was to estimate force of muscles that constituted the rotator cuff during elevation motion in scapula plane, using a skeletal muscle model and quantitatively evaluate rotator cuff function in vivo. A healthy volunteer was measured with an open MR and CT system at elevation positions in scapula plane (MR: $30^{\circ}$, $60^{\circ}$, $90^{\circ}$, $120^{\circ}$, $150^{\circ}$, CT: $0^{\circ}$). After reconstruction three-dimensional MRI-based and CT-based bone surface models, matched each models with registration technique. Then supraspinatus, infraspinatus, subscapularis, teres minor, deltoid (anterior, middle, posterior portions) represented as plural lines. These lines were proportional to physiologic cross-sectional area (PCSA) and defined straight line to bind origin and insertion. Force of supraspinatus became greatest at $59^{\circ}$ of elevation. Subsequently force of deltoid middle portion became greatest at $89^{\circ}$ of elevation. Infraspinatus and subscapularis were active at the meantime. In addition, supraspinatus was active during elevation. These results resembled clinical finding and were proved force couples that contribute to mobility and stability of shoulder complex.

This study suggests isolated Type IV-MO or Type IV-LO fractures could be treated with nonsurgical treatment because they do not interfere with normal elbow kinematics. Valgus and external rotation instability were influenced by total articular surface, however, posterior and proximal translation were influenced by isolated articular surface involvement of coronoid. Further clinical studies are warranted to validate these in vitro findings.

불안정한 주관절이 동반된 전위된 구상돌기 골절들을 내측 접근법을 통한 금속판 고정으로 안정된 고정과 만족스러운 골유합을 얻을 수 있었다.

Repeated pulling-out of a suture anchor in the lateral row despite repeated attempts at insertion during a rotator cuff repair is not uncommon with the suture-bridge technique, especially in patients with osteoporosis. We describe a simple procedure for dealing with the pull-out of a PushLock anchor in the lateral row using a suture anchor with a suture eyelet during rotator cuff repair applying the suture-bridge technique.

Compartment syndrome is not uncommon in the forearm or lower extremity, but it is relatively rare in the upper arm. This rarity might delay the diagnosis, especially in the unconscious or intoxicated patient. Therefore, a high index of suspicion is needed to make an accurate, early diagnosis. Although excessive muscle strain leading to localized compartment syndrome is seldom encountered in the upper arm, three cases of compartment syndrome in the upper arm after blunt injury have been reported. Interestingly, there were no bony injuries in any of these patients. However, there are only two reports of isolated dorsal compartment syndrome after blunt trauma. The present report presents the case of a patient who had blunt trauma to the upper arm that resulted in the development of compartment syndrome in the isolated dorsal compartment of the upper arm.

To prevent distraction and varus deformity between the humeral head and shaft, tension band sutures placed between the head of the interlocking screw and the rotator cuff, and we recommend using nonabsorbable sutures. We describe our simple procedure to overcome these difficulties in tension band suturing after reducing a proximal humerus fracture to maintain the reduction.

After preparation of the bone bed, two doubly loaded suture anchors with suture eyelets are inserted at the articular margin of the greater tuberosity. A retrograde suture-passing instrument penetrates the rotator cuff to retrieve the sutures through the modiWed Neviaser or subclavian portal. An ipsilateral pair of suture eyelets in the suture anchor is passed through the margins of the rotator cuff tear. The blue suture of the second and third pair is pulled out of the lateral cannula, and the threaded blue suture of the third pair in the needle is passed through the blue suture of the second pair. After retrieving the blue suture of the firrst pair through the anterior portal, it is pulled out to pass the blue suture of the third pair through the eyelet of the anteromedial anchor. The blue suture is linked between two anchors. The medial row of suture bridge is repaired with a sliding knot, and the sutures are not cut. Once the rotator cuff repair using the suture-bridge technique has been performed, the two blue strands in the anterior portal are tied. We describe our technique that possesses the advantages of both the double-pulley and suturebridge techniques, which improves the pressurized contact area and maximizes compression along the medial row.

The acromioclavicular-hook-plate is one of the surgical treatments for distal clavicle fracture and traumatic acromioclavicular (AC) joint dislocation. Although this procedure can obtain rigid and accurate anatomical reduction of the AC joint, secondary widening of the hook-hole in the acromion is often seen during postoperative follow-up. This complication is owing to the high-degree of mobility of the AC joint. Therefore, it is important to evaluate the effect on these complications due to the position of the hook-hole. The purpose of the present study is to investigate three-dimensionally the effect due to the position of the hook-hole during arm abduction motion. We studied in vivo and three-dimensional kinematics of the normal shoulder joint with use of a markerless bone-registration technique. Magnetic resonance images of 14 shoulders of 7 healthy volunteers were acquired in 7 positions between $0^{\circ}$ and $180^{\circ}$ of abduction. We created three-dimensional computer models of the bones and the acromioclavicular-hook-plate. Based on the three-dimensional kinematics data, we simulated the widening of the hook-hole each different positioning of the hook-hole. The widths of the hook-holes almost linearly increased. And these widths significantly increased, when we put the hook-hole on the acromion from AC joint to 20 mm and 25 mm posterior position.

Despite its importance for the understanding of joint kinematics in vivo, there has been few studies about shoulder joints. The purpose of this study is to analyze the glenohumeral joint during internal and external rotation at 90 degrees of abduction using in vivo noninvasive motion analysis system. MRI was performed for the following seven positions from maximum internal rotation to maximum external rotation at intervals of 30 degrees. We used 3D-gradient echo sequencing (TR: 12 ms, TE: 5.8 ms, 0.8 mm-slice thickness). Our method is based on matching three-dimensional MR images by the similarity of the image intensity. We analyzed the in vivo three-dimensional motions of the glenohumeral and scapulothoracic joint during this motion. In scapla plane, the mean rotation angle of the glenohumeral join was 105.5 degrees ($SD{\pm}39.0^{\circ}$). The mean rotation angle of the scapulothracic joint was 27.5 degrees ($SD\;{\pm}\;7.7^{\circ}$). The contribution ratio is almost 3.8:1 of glenohumeral and scapulothracic joint respectively.

관절와 및 상완골의 의미 있는 골결손을 동반한 불안정한 견관절에 대해 어떻게 최선의 치료를 할 것인가에 대한 의문은 남아있다. 어떤 저자들은 외회전과 외전을 제한하는 것으로 Hill-Sachs 병변의 진입을 예방하는 일종의 관혈적 관절낭 변위를 통한 제한된 상완와관절 운동을 주장해왔으며, 다른 관혈적 시술들은 극하근건과 관절낭을 Hill-Sachs 병변 내로 관혈적 전이시키는 것으로 기술되어왔다. 최근에는 여러 저자들에 의해 Hill-Sachs 병변의 진입을 치료하는 더 새로운 접근법들이 기술되었으며, Bankart 병변 복원술에 더하여 Hill-Sachs 병변을 채우기 위해 관절경 하 후방 관절낭 고정술과 극하근건 고정술로 이루어진 이른바 'Remplissage'술기가 소개된 바 있어, 이에 저자는 외상성 견관절 불안정성으로 관절경 하 Bankart 병변 복원술 및 관절낭 축화술 시행 후 외상으로 재발된 견관절 불안정성이 발생하여 관절경 하 Bankart 병변 복원술과 함께'Remplissage'술기를 이용한 Hill-Sachs 병변 복원술을 시행한 예를 보고하는 바이다.

Eleven shoulders (9 patients) with refractory scapulothoracic dysfunction were treated with scapulothoracic arthrodesis between 2000 and 2006. Refractory shoulder dysfunction included facioscapulohumeral muscular dystrophy in five shoulders (3 patients), refractory scapular winging with long thoracic nerve palsy in one shoulder, scapular winging caused by serratus anterior palsy with trapezius dysfunction in one shoulder, post-surgical thoracic outlet syndrome due to medial clavicle resection in two shoulders, refractory scapular winging with spinal accessory nerve injury in one shoulder, and chronic trapezius rupture caused by cervical spine surgery in one shoulder. The mean active flexion was improved from 82 degrees preoperatively to 112 degrees postoperatively. The mean Constant score was improved from 27.2 points to 68.0 points. Two shoulders (1 patient) that had facioscapulohumeral muscular dystrophy had broken wires due to nonunion, and one patient had a reactive pulmonary effusion. In ten of the eleven shoulders, the patients were satisfied with their results. The scapulothoracic arthrodesis can cause significant pain relief and functional improvement in refractory scapulothoracic and/or shoulder dysfunction. By selecting patients that present with appropriate indications, and using experienced surgical technique through complete preoperative evaluation, we can diminish the complication rate and make good clinical outcomes.

For a bursal-side retracted laminated rotator cuff tear, simple repair of the retracted bursal-side rotator cuff might be insufficient because the repaired tendon could remain as an intratendinous tear of the rotator cuff. We present a repair method for intratendinous rotator cuff tears using the suture-bridge technique. We believe that this method helps to preserve the remnant rotator cuff tendon without tissue damage and restores the normal rotator cuff footprint in bursal-side delaminated rotator cuff tears.

The clinical outcomes of arthroscopic Intra-articular Repair for an Isolated Partial Articular-Surface Tear of the Subscapularis Tendon

In fencing, athletes must hit opponents by the sword of fencing, so they need long reach between their foot and their tip of the sword. We thought the motion of shoulder joint, mainly scapula, is one of the important roles in this action and noticed the difference of right and left side in muscles around scapula caused by this action. We evaluated these muscles with MRI imaging in 5 high-level athletes of fencing who aims at the next Olympics (3 men and 2 women, their average age is 21 years). Besides we observed their physical measurement related with these muscles. We reported the characteristics of these results.

Primary malignant bone tumors of the scapula are very rare, and little literature is available regarding their characteristics and outcome. We studied the clinical characteristics, and outcome of patients with primary malignant bone tumors of the scapula. From 1979 to 2008, we treated 7 patients at our institute (4 men and 3 women; chondrosarcoma 3, Ewing's sarcomas 3, Osteosarcoma 1). The mean age was 45 years (range, 5~65 years). The follow-up period was 2 - 180 months. Six patients were performed operations: total scapulectomy 3, partial scapulectomy 1, forequarter resection 1, total resection of the shoulder girdle (Tikhoff-Linberg procedure) 1. No-operative treatment was chosen for one patient with a limited life expectancy. Local recurrence occurred in one patient. Distant metastasis occurred in 3 patients. Of the 7 patients, 4 patients are died because of propagation of the disease. Three patients were alive and apparently disease-free, and these patients were evaluated for functional results with the functional evaluation system of the International Society of Limb Salvage (ISOLAS). Functional result of partial scapulectomy was excellent, however, the function after total scapulectomy or Tikhoff-Linberg procedure is severely impaired. Our study indicates reconstruction procedure needs to be reconsidered following total scapulectomy or Tikhoff-Linberg procedure.

견관절 전방 외상성 불안정증에서 관절 낭-순 재건술은 재발성 불완정증 예방 및 기능 회복에 있어 매우 성공적인 술식이다. 그러나 관절 와의 30 % 이상의 심한 골 결손이 존재 할 때 관절 낭-순 재건술 만으로는 성공적인 결과를 가져오기 힘들다. 본 연구는 관절 와의 심한 골 결손을 가진 재발성 전방 외상성 불안정성 견관절에서 관절외 자가 장골 이식으로 보강한 관절 낭-순 재건술의 술기와 결과를 보고하고자 한다.