Duranthon L D, Augereau B, Thomazeau H, Vandenbussche E, Guillo S, Langlais F
Service d'Orthopédie Traumatologie B, Hôpital Européen Georges Pompidou, 20, rue Leblanc, 75015 Paris.
Rev Chir Orthop Reparatrice Appar Mot. 2002 Feb;88(1):28-34.
A series of 13 patients with an excentered osteoarthritis of the glenoid who underwent bipolar shoulder arthroplasty is reported.
The series included 13 patients treated in two centers between 1995 and 1998. Mean age was 70 years (58-88). Constant's absolute score and Swanson's score were used for clinical assessment. The Hamada and Fukuda classification was used for the radiographic assessment. The follow-up radiography series included an AP view in the three rotation positions, an AP view in maximum abduction to assess intraprosthetic mobility, a lateral view (Lamy) and measurements of both humeri. Several measurements were made to assess humerus lateralization and glenoid wear: deltoid lever arm, lateral humeral displacement, distance between the lateral border of the coracoid and the center of the glenoid and the subacromial space. Mean preoperative Constant score was 23 points: pain 3 pts, activity 5 pts, motion 13 pts, force 2 pts. Mean preoperative Swanson score was 11. Active anteflexion was 78 degrees, active abduction 68 degrees and passive external rotation 17 degrees. The Hamada and Fukuda classification was 9 grade 4 and 4 grade 5. All patients had a full thickness unrepairable rotator cuff tear: three with 2 tendon tears, and 10 with 3 tendon tears. All patients were reviewed clinically and had a complete radiography series at last follow-up (mean 28 months, range 7 - 56 months).
At last follow-up, the mean absolute Constant score was 37 points: pain 10 pts, activity 9 pts, motion 14 pts, force 4 pts. Mean Swanson score at last follow-up was 19 points. Mean active anteflexion was 69 degrees, active abduction was 63 degrees and passive external rotation was 29 degrees. A satisfactory deltoid lever arm had been achieved compensating the glenoid wear by a greater lateral displacement of the humerus. At last follow-up, there were no cases of humeral loosening but three cases with important glenoid wear were observed after two years. Comparing the results obtained using small cups (40 and 44) with arthroplasties using large cups (48 and 52) showed a trend favoring small cups: Constant score 43 vs 32 points, Swanson score 21 versus 17 points, anteflexion 72 degrees versus 66 degrees and passive external rotation 34 degrees versus 26 degrees.
Our results confirmed the efficacy of bipolar arthroplasty for pain relief, but the mobility outcome was less than satisfactory, excepting passive external rotation. It would appear to be preferable to use small cups. Comparing our results with data in the literature, particularly the better results for mobility using simple humeral prostheses, suggests that the principles of shoulder and hip arthroplasty concern different mechanisms: a sufficient deltoid lever arm must be achieved, but without overstretching the periarticular soft tissue (capsule, subcapsule, teres minor), and using a cup size close to the size of the healthy humeral head. Glenoid reaming should not be reserved only for asymmetrical glenoid wear in the horizontal plane.
Our results suggest that bipolar arthroplasty for excentered osteoarthritis of the glenoid cavity is indicated for: stiffness in external rotation, major concentric wear in patients under 65 years of age, or asymmetric glenoid wear.
报告13例接受双极肩关节置换术治疗的肩胛盂偏心性骨关节炎患者。
该系列包括1995年至1998年间在两个中心接受治疗的13例患者。平均年龄为70岁（58 - 88岁）。采用Constant绝对评分和Swanson评分进行临床评估。采用Hamada和福田分类法进行影像学评估。随访X线片系列包括三个旋转位的前后位片、最大外展位的前后位片以评估假体内部活动度、侧位片（拉米位）以及双侧肱骨的测量。进行了多项测量以评估肱骨侧方移位和肩胛盂磨损：三角肌杠杆臂、肱骨外侧移位、喙突外侧缘与肩胛盂中心之间的距离以及肩峰下间隙。术前Constant评分平均为23分：疼痛3分、活动度5分、活动范围13分、力量2分。术前Swanson评分平均为11分。主动前屈为78度，主动外展为68度，被动外旋为17度。Hamada和福田分类为9例4级和4例5级。所有患者均有全层不可修复的肩袖撕裂：3例为2条肌腱撕裂，10例为3条肌腱撕裂。所有患者均进行了临床复查，并在末次随访时（平均28个月，范围7 - 56个月）进行了完整的X线片系列检查。
末次随访时，Constant绝对评分平均为37分：疼痛1分、活动度9分、活动范围14分、力量4分。末次随访时Swanson评分平均为19分。平均主动前屈为69度，主动外展为63度，被动外旋为29度。通过肱骨更大的侧方移位实现了满意的三角肌杠杆臂，从而补偿了肩胛盂磨损。末次随访时，无肱骨松动病例，但2年后观察到3例肩胛盂严重磨损病例。将使用小盂杯（40和44）的置换结果与使用大盂杯（48和52）的置换结果进行比较，显示出倾向于小盂杯的趋势：Constant评分43分对32分，Swanson评分21分对17分，前屈72度对66度，被动外旋34度对26度。
我们的结果证实了双极置换术在缓解疼痛方面的疗效，但除被动外旋外，活动度结果不尽人意。似乎使用小盂杯更为可取。将我们的结果与文献数据进行比较，特别是使用单纯肱骨假体时活动度更好的结果，表明肩关节置换术和髋关节置换术的原则涉及不同机制：必须实现足够的三角肌杠杆臂，但不能过度拉伸关节周围软组织（关节囊、关节囊下、小圆肌），并且使用接近健康肱骨头大小的盂杯尺寸。肩胛盂扩孔不应仅用于水平面的不对称肩胛盂磨损。
我们的结果表明，双极置换术适用于肩胛盂偏心性骨关节炎的情况为：外旋僵硬、65岁以下患者的主要同心性磨损或不对称肩胛盂磨损。
