A Review Paper The Arthritic, Cuff-Deficient Shoulder— When Is Hemiarthroplasty Enough? Carl Basamania, MD, FACS, and Jeffrey Visotsky, MD, FACS KINEMATICS Abstract The glenohumeral joint lacks significant intrinsic bony This article outlines the role of hemiarthroplasty in the stability. Dynamic stabilization of the joint is provided treatment of cuff-tear arthropathy. Rotator cuff tear by ligament support, coupled with the rotator cuff arthropathy, kinematics, and classification are reviewed. compressive force vector within the concavity of the glenoid fossa. The infraspinatus and supraspinatus otator cuff arthropathy is a relatively newly rec- offer inferiorly directed forces, which exert a center- ognized condition. In 1934, Codman1 described a ing effect throughout shoulder motion.4 Radiographic case of arthritis as the result of a large retracted and electromyographic analysis of patients with rotator rotator cuff tear. Previous reports of patients cuff–deficient shoulders has provided further insight Rwith massive cuff tears and degenerative conditions into the kinematics of the shoulder. Stable force couples of the shoulder had been reported as early as 1857.2 can exist in a cuff-deficient shoulder if transverse forces Neer and colleagues3 coined the term cuff-tear arthropathy between subscapularis and posterior–inferior structures and described the pathoanatomical changes of a chronic are balanced.4 Disruption of the stable kinematics or massive rotator cuff tear combined with superior migra- loss of coronal deltoid forces leads to unstable kine- tion of the head, instability, erosion of the acromion, and matics and loss of overhead function. Captured fulcrum head osteoporosis with collapse of subchondral bone. mechanics is a condition in which the cuff-deficient Superior displacement of the humerus into the subacro- shoulder is able to function with stable kinematics. mial space resulted in erosion of the greater tuberosity Some patients with cuff-tear arthropathy maintain over- (femoralization) and subsequent morphologic changes to head function with captured fulcrum mechanics; they the coracoacromial arch (acetabularization). This article depend on the coracoacromial arch, balanced rotator outlines the role of hemiarthroplasty in the treatment of cuff force couples, and a functional anterior deltoid to cuff-tear arthropathy. contain the head, thus stabilizing the shoulder for active Neer and colleagues3 proposed 2 interdependent mecha- forward elevation.5 In the absence of captured fulcrum nisms—nutritional and mechanical—for the development kinematics, overhead function cannot be restored with and progression of cuff-tear arthropathy. When a patient hemiarthroplasty. Therefore, preoperative kinematics sustains a rotator cuff tear, several nutritional and mechan- and postoperative patient functional expectations are ical changes take place in the shoulder. There is loss 2 of the most important guiding factors in choosing of the normal envelope and capsule about the shoulder, between hemiarthroplasty and reverse arthroplasty for which can result in loss of containment of synovial fluid, the arthritic, cuff-deficient shoulder. with subsequent malnutrition of the articular cartilage.3 Loss of cuff function can cause unbalanced forces about PATIENT EVALUATION the shoulder, with subsequent superior migration of the The most common conditions associated with cuff-tear humeral head. This results in mechanical impingement of arthropathy—and the only true consistent findings— the head under the acromion and mechanical abrasion of are atrophy of the supraspinatus and infraspinatus the cartilaginous surfaces. The incidence of rotator cuff muscles and weakness of external rotation. Because arthropathy is unknown. Neer and colleagues suggested an external rotation lag sign (Figure 1) may be pres- that about 4% of patients with cuff tears later develop ent as a result of loss of function of external rotators, cuff arthropathy. specifically the infraspinatus and teres minor, it is important to determine strength of external rotation. The status of the subscapularis, the loss of which can have significant detrimental effects on shoulder func- Dr. Basamania is Orthopaedic Surgeon, Triangle Orthopaedic Associates, Durham, North Carolina. tion, should be assessed with a lift-off or stomach push test (Figure 2). Active and passive motion should be Dr. Visotsky is Orthopaedic Surgeon, Illinois Bone and Joint assessed. Passive motion is typically well preserved in Institute, Chicago, Illinois. patients with cuff arthropathy. Loss of passive exter- nal rotation is unusual; however, excessive passive Am J Orthop. 2007;36(12 Supplement):18-21. Copyright Quadrant external rotation may be indicative of subscapularis HealthCom Inc. 2007. All rights reserved. rupture. Posterior capsular contracture can be assessed 18 A Supplement to The American Journal of Orthopedics® C. Basamania and J. Visotsky Type IA Type IB Type IIA Type IIB Centered stable Centered- Uncentered- Uncentered- medialized limited stable stable No superior migration Superior Anterior–superior translation dislocation Acetabularization Medial erosion Minimum No stabilization by of CA arch; of the glenoid stabilization by CA arch femoralization of CA arch humeral head Figure 1. An external rotation lag sign (left) is indicative of pos- terior rotator cuff deficiency. CA indicates coracoacromial Figure 3. The Seebauer classification divides cuff tear arthrop- athy based on absence (type I) or presence (type II) of fixed proximal migration. Type IB is characterized by medial ero- sion. Types IIA and IIB differ in degree of fixed proximal migration. From: Visotsky JL, Basamania C, Seebauer L, Rockwood CA, Jensen KL. Cuff-tear arthropathy: patho- genesis, classification and algorithm for treatment. J Bone Joint Surg Am. 2004;86(suppl 2)35-40.6 Reprinted with permission from The Journal of Bone and Joint Surgery, Inc. Seebauer6 proposed a radiographic classifica- tion of cuff-tear arthropathy and related condi- tions (Figure 3). This classification is based on Figure 2. Inability to compress the abdomen and hold the arm forward (positive abdominal compression test) is indicative of analysis of failed treatments and the presumed biome- 6 subscapularis deficiency. chanics leading to those failures. Two types of patients (4 distinct subgroups) have been formed on the basis of by checking internal rotation with the arm abducted the biomechanics and clinical outcomes of arthroplasty 90° and the scapula stabilized. Significant posterior for cuff-deficient shoulders. In type I, kinematics are capsular contracture may shift the instant center of stable; in type II, kinematics are unstable from loss of rotation of the humeral head anterosuperiorly dur- a captured fulcrum. Types I and II are distinguished ing flexion, exacerbating any impingement problems. by the presence of static superior migration of the Anterosuperior migration might be the cuff-arthropa- center of rotation, the amount of instability of the thy equivalent of obligate posterior translation of the center of rotation, and associated changes to the cora- humeral head resulting from internal rotation contrac- coacromial arch structures. Type I patients lack static ture, commonly found in glenohumeral osteoarthritis superior migration. Type IA patients have typical cuff with an intact cuff. arthropathy changes—specifically, acetabularization of Several functional parameters may predict successful the acromion and femoralization of the head. Type IB hemiarthroplasty for cuff-tear arthropathy. Active forward patients exhibit medial erosion. Type II patients dem- flexion beyond 70° is one such parameter. As loss of active onstrate varying degrees of static superior migration. elevation may be exacerbated by pain, 10 mL of lidocaine Type IIA patients have significant proximal migration can be injected into the subacromial space to treat pain but maintain relatively stable kinematics. Finally, type and better evaluate active elevation. Demonstration of IIB patients have anterosuperior escape because of the active initiation and force against gravity with forward loss of the coracoacromial arch. flexion indicates that the patient likely has stable kine- matics that can be addressed without resorting to a reverse TREATMENT OPTIONS— prosthesis. A critical assessment of anterior deltoid HUMERAL HEMIARTHROPLASTY OR and subscapularis function is needed in the decision- REVERSE ARTHROPLASTY making process. Deficient anterior structures that may The treatment goals of cuff-tear arthropathy are simi- have been violated or weakened by prior surgical pro- lar to those of standard degenerative and inflamma- cedures involving the coracoacromial arch may contra- tory arthritis: pain relief, restoration of glenohumer- indicate the choice of hemiarthroplasty for cuff-tear al stability, and improvement of functional motion. arthropathy. If hemiarthroplasty is performed in the set- Cuff-tear arthropathy presents a unique surgical chal- ting of complete subscapularis rupture, pectoralis major lenge. Numerous surgical procedures, including total transfer should be considered. shoulder arthroplasty (TSA), bipolar arthroplasty, large December 2007 19 The Arthritic, Cuff-Deficient Shoulder—When Is Hemiarthroplasty Enough? RCDA shoulder Irreparable rotator cuff tear • Competent coracoacromonial arch • Deficient coracoacromonial arch • Stable fulcrum (Type I) • Unstable fulcrum (Type II) • Older patient • Younger patient and • Younger patient heavy