Healing of reamed glenoid bone articulating with a metal humeral hemiarthroplasty: a canine model.

This study characterizes the healing response of the glenoid after spherical reaming and prosthetic humeral head replacement in a canine model of glenohumeral hemiarthroplasty. The right glenoid of twelve skeletally mature female dogs was reamed to a uniform radius of curvature, removing all cartilage down to bleeding subchondral bone. The glenoid was not resurfaced. The humeral head was replaced with a stemmed metal prosthesis. Post-surgery, the operated limbs were immobilized for seven days, with motion allowed ad libitum thereafter. Fluorescent bone labels were administered to identify bone formation. These procedures were not complicated by instability, infection or death. Six animals were euthanized at 10 week and six more at 24 week. The intact glenohumeral joints were evaluated by gross examination, assessment of glenoid concavity, and light microscopy of methylmethacrylate sections. At 10 week, vascular fibrous tissue partially covered the glenoid, maintaining a concave surface congruent with the prosthetic humeral head. New bone formed at the margin of the glenoid, and the density of the periarticular trabecular bone increased. At 24 week, the healing was more advanced; thick fibrocartilaginous tissue covered the entire glenoid surface. These results demonstrate that spherical glenoid reaming produced a consistent healing response characterized by remodelling of the reamed bony concavity to a congruent, living, smooth, securely attached interface articulating with the humeral prosthesis.     

骨性缺损对肩关节稳定性影响的研究

目的探讨肩关节骨性缺损对关节稳定性的影响,为临床提供理论依据。方法分别制作肩胛盂及肱骨头缺损模型并逐渐增加缺损程度;以盂肱关节旋转中立位、60°外展位为起始位置,逐渐增加外旋角度至盂肱关节脱位,测量脱位发生前肱骨头前移距离;保持盂肱关节外展60°,分别在旋转中立位及外旋60°位时增加轴向应力,直至盂肱关节脱位,测量脱位前肱骨头的应力强度变化。结果随着肩胛盂及肱骨头缺损程度增加,外旋角度增加,肩关节稳定性下降,肱骨头位移不断增大,各组间呈显著性差异(P<0.01);盂肱关节外展60°、旋转中立位时,肱骨头应力强度随着骨缺损增大而不断增大,正常应力强度从1.68 Mpa迅速增加至4.62 Mpa,各组间呈显著性差异(P<0.01);盂肱关节外展60°、外旋60°时,正常应力强度为1.94 Mpa,骨缺损时迅速增加至6.65 Mpa,各组间呈显著性差异(P<0.01);肩关节不同缺损时,其接触力学特性证实了对肩关节稳定性有较大的影响,肩关节不稳定现象十分突出。结论随着肩胛盂及肱骨头缺损范围的增大,肩关节稳定性不断下降,肱骨头位移和应力强度不断增加,以致发生提前脱位。     

Neglected anterior dislocation of shoulder with large Hillsach's lesion & deficient glenoid: Treated by autogenous bone graft & modified Latarjet procedure

Neglected anterior dislocation of shoulder is rare in spite of the fact that the anterior dislocation of the shoulder is seen in around 90% of the acute cases. Most of the series of neglected dislocation describe posterior dislocation to be far more common.^1,2 We hereby report a case of the neglected anterior shoulder dislocation in a 15 year old boy who had a history of epilepsy. There was a large Hill Sachs lesion in humeral head which was impacted in glenoid inferiorly and glenoid was eburnated at that margin. The humeral head was reconstructed with a tricortical iliac graft. Glenoid was reconstructed by transfer of coracoids process of scapula to antero-inferior glenoid (modified Latarjet procedure). This case is unique because management of humeral head defect with bone graft is not mentioned in anterior dislocation.     

Treatment of glenoid loosening and bone loss due to osteolysis with glenoid bone grafting

Twenty-four patients underwent conversion of a total shoulder replacement to a humeral head replacement with glenoid bone grafting for glenoid loosening due to osteolysis. Of the 24 patients, 18 (75%) had satisfactory pain relief at a mean follow-up of 33.4 months (range, 24-63 months). Four had good pain relief with conversion back to total shoulder replacement at a mean of 11 months (range, 9-15 months) after the index procedure, thus bringing the rate of overall satisfactory pain relief to 92%. Two patients continued to report significant pain and were not satisfied with the procedure. Significant functional motion improvements were not seen (P > .05). Graft subsidence was seen in 10 of 20 cases (50%). Bone grafting of glenoid defects in revision arthroplasty provides satisfactory improvement in terms of pain relief and, by improving bone stock, allows for placement of a glenoid component at a later date if there is persistent pain. However, high rates of graft subsidence are concerning.     

Recurrent, locked posterior glenohumeral dislocation requiring hemiarthroplasty and posterior bone block with humeral head autograft

This article describes the case of a 77-year-old man with a recurrent posterior shoulder dislocation, treated with humeral hemiarthroplasty and reconstruction of a large posteroinferior glenoid defect with a bone block created from humeral head autograft. On examination, the patient's left arm was held in internal rotation against his stomach, with minimal swelling about the deltoid. His shoulder was nontender to palpation; however, he had substantial motion restrictions, and attempted motion was painful. He could forward elevate to 30°, extend to 0°, internally rotate to belly, and passive external rotation was limited to -30°. He maintained full elbow, wrist, and hand range of motion, and his neurovascular examination was intact. Radiographs revealed a recurrent posterior glenohumeral dislocation, with a large reverse Hill-Sachs defect involving the lesser turberosity and humeral head. Computed tomography with 3-D reconstruction revealed the humeral head defect involving the lesser tuberosity and approximately 40% of the humeral head and a large comminuted posteroinferior glenoid fracture measuring 2.7×0.8 cm, encompassing approximately 30% of the posteroinferior glenoid surface. Standard fixation was not possible; therefore, the resected humeral head was fashioned into an elliptical piece mirroring the size of the defect of the posteroinferior glenoid. Rough measurements of the defect were made and marked on the humeral head, which was then cut with an oscillating saw to approximate the size and shape of the defect. The glenoid graft provided an extension to the glenoid and prevented posterior subluxation with no block to motion. One year postoperatively, he had full strength (5/5) with external rotation, forward elevation, and internal rotation, 140° of active forward elevation, 30° of external rotation, internal rotation to T7, and no episodes of instability. To our knowledge. this is the first report of this technique in the literature. It is an alternative to total shoulder arthroplasty.     

Glenoid corticocancellous bone grafting after glenoid component removal in the treatment of glenoid loosening

Nine patients underwent removal of a loose glenoid component and corticocancellous iliac crest autografting of the bony defect. No revision glenoid components were inserted. Eight bony defects were large, central, and cavitary, and one had an additional peripheral component. Patients were evaluated with a subjective assessment, Constant score, and radiographs at a mean follow-up of 30 months (range, 24-39 months). By use of Neer criteria, the result was considered satisfactory in 5 patients and unsatisfactory in 4. Functional improvement was modest, with the mean Constant score increasing from 46.3 to 49.9 points. Radiographs revealed a mean 4.1 mm of medialization of the humeral head within the glenoid (range, 1-11 mm). Two cases showed wear of the bone graft, thought to be induced by eccentric glenoid loading due to rotator cuff insufficiency. No other case demonstrated wear or graft resorption. One patient required reoperation for a massive rotator cuff tear; at the time of surgery, excellent glenoid bone continuity was observed, allowing implantation of a reverse prosthesis. Corticocancellous autografting appears to be a reliable procedure for restoration of glenoid bone stock after removal of a loose glenoid component. Although functional gains were modest, restoration of the glenoid bone component allows implantation if deemed necessary.     

Recurrent shoulder instability and arthritis treated with graft jacket resurfacing, hemiarthroplasty, and bone grafting

The treatment of recurrent shoulder instability in the presence of large bony defects of the glenoid and/or the humeral head is evolving. The young patient with significant glenohumeral arthrosis presents unique challenges in terms of management. In the presence of large glenohumeral bony defects, several authors have reported poor outcomes with attempted soft tissue stabilization only. Therefore, some type of bony reconstruction is generally recommended. Glenohumeral arthrosis is a known complication of recurrent shoulder dislocation. The role of arthroplasty and glenoid resurfacing options in young patients is controversial given the demands in this group. This article presents a case of a 35-year-old patient who presented with coexisting bony defects-an engaging Hill-Sachs defect and a bony Bankart defect causing recurrent shoulder instability-and post-dislocation glenohumeral arthritis with resultant pain. He underwent a humeral hemiarthroplasty, glenoid structural bone grafting, and a glenoid graft jacket. At 2-year follow-up, he reported a favorable outcome. This case represents an encouraging treatment approach for a young patient with recurrent instability caused by coexisting bony defects and significant arthrosis.     

Radiographic analysis of bone defects in chronic anterior shoulder instability

Purpose: To describe the incidence of bony lesions accompanying chronic anterior shoulder instability using fluoroscopically controlled radiography. Type of Study: Case series of radiographic findings of patients with chronic anterior shoulder instability. Methods: Radiographs of 160 shoulders in 156 patients with recurrent anterior shoulder instability were retrospectively evaluated; 132 shoulders had experienced recurrent dislocations, 18 shoulders had experienced recurrent subluxations, and 10 shoulders showed evidence of anterior instability at arthroscopy despite no reported history of instability. Fluoroscopically controlled radiographic views included an anteroposterior view with the humeral head in 3 rotations and a glenoid profile view with a comparison view of the contralateral shoulder. Results: A humeral impaction fracture was identified on the anteroposterior radiographs in 117 of 160 shoulders (73.1%). The glenoid profile view showed an osseous lesion of the glenoid in 126 of 160 shoulders (78.8%). The anteroposterior radiograph showed an osseous lesion of the glenoid in an additional 13 shoulders (8.2%). Overall, an osseous lesion, either humeral or glenoid, was identified in 152 of 160 shoulders (95.0%). Conclusions: This study shows the frequent presence of bony lesions in patients with anterior shoulder instability.     

Oberflächenersatz des Humeruskopfs

Cup resurfacing of the humeral head is one of the possible prosthetic solutions for severe destruction of the glenohumeral joint. Because neurological complications are not uncommon after total shoulder arthroplasty using surface replacement, these cups are indicated when hemiarthroplasty is possible. The advantages of humeral head resurfacing are bone preservation and the technically easy exchange if revision is necessary; therefore, young patients are candidates for this type of endoprosthesis. At present humeral head resurfacing is indicated for osteoarthritic destruction of Walch types A1 and C, for rheumatic destruction with deficient cuff in younger patients, cuff arthropathy in younger patients with Seebauer types 1A and 1B, humeral head necrosis with normal glenoid and necrotic bone in less than one third of the humeral head and dislocation arthropathy in younger patients.     

Shoulder arthroscopy: setting, portals and normal exploration

Arthroscopy has been established as a valuable technique in diagnosis and treatment of the injured and deseased shoulder. Arthroscopy is not a new diagnostic tool but offers new approaches to the surgical treatment of shoulder pathology. Shoulder arthroscopy is usally performed under general anesthesia or/with scalene block. The patient is positioned in opposite lateral decubitus position or in beach chair position. Diagnostic arthroscopic is initiated with insertion of the arthroscope from the posterior portal into the gleno humeral joint. Inspection should be organized systematic visualization of the entire joint (articular surfaces of the glenoid and humeral head, glenoid labrum, long head of the biceps tendon, sub scapularis tendon, axillary pouch, capsular ligaments, synovial membrane). Then endoscopic visualization of the subacromail space is a valuable and essential adjunct to the gleno humeral arthroscopy (impingement syndrome, rotator cuff tears, calcific tendinitis, acromiocalvicular joint disorders).     

Arthroscopic findings in the subluxating shoulder

The arthroscopic findings in 19 shoulders (18 patients) with subluxation are described. The clinical diagnosis of subluxation of the shoulder is primarily based on clinical history with inconsistent physical findings and radiographic studies. Arthroscopic findings in these patients were consistent. Increased translation of the humeral head in the anteroposterior plane was noted secondary to attenuation of the anteroinferior glenohumeral ligament. Incompetence of this ligamentous structure obviated its function as an anterior buttress and allowed the humeral head to translate anteriorly on the glenoid. Fraying, tearing, or detachment of the anteroinferior glenoid labrum and articular defects in the posterolateral humeral head were also consistent findings, thought to be secondary to repeated injury as the humeral head translates forward and backward in the glenoid fossa. In several cases the classic "click" that occurs with subluxation of the shoulder could be reproduced under arthroscopic visualization and corresponded to the defect in the posterolateral humeral head riding over the torn labrum and/or anterior glenoid rim. Shoulder arthroscopy is an accurate method for confirming the clinical impression of subluxation of the shoulder, especially in subtle glenohumeral instability, and should be helpful in selecting specific surgical reconstruction procedures.     

Long-term results of total shoulder arthroplasty following bone-grafting of the glenoid.

BACKGROUND: The marked loss of glenoid bone volume or alteration of glenoid version can affect glenoid component fixation in patients undergoing total shoulder arthroplasty. The purpose of this study was to evaluate the long-term results associated with the use of bone-grafting for restoration of glenoid volume and version at the time of total shoulder arthroplasty. METHODS: Twenty-one shoulders received an internally fixed, corticocancellous bone graft for the restoration of peripheral glenoid bone stock at the time of total shoulder arthroplasty between 1980 and 1989. Grafting was indicated when glenoid bone stock was insufficient to maintain adequate version or fixation of the prosthesis. Seventeen shoulders were available for follow-up; the average duration of follow-up for the thirteen shoulders that did not have prosthetic failure within the first two years was seventy months. Total shoulder arthroplasty was performed because of osteoarthritis in five shoulders, chronic anterior fracture-dislocation in five, capsulorrhaphy arthropathy in three, inflammatory arthritis in two, recurrent dislocation in one, and failure of a previous arthroplasty in one. All patients had some form of anterior or posterior instability preoperatively. There were five anterior and twelve posterior glenoid defects. Bone from the resected humeral head was used for grafting in fifteen shoulders, and bicortical iliac-crest bone was used in two. RESULTS: The average glenoid version after grafting was 4 degrees of retroversion, with an average correction of 33 degrees. The graft failed to maintain the original correction in three shoulders due to nonunion, dissolution, or shift. Five total shoulder replacements failed, necessitating glenoid revision at two to ninety-one months postoperatively. The failures were associated with recurrent massive cuff tears (one shoulder), persistent instability (two shoulders), improper component placement (one shoulder), and loss of graft fixation (one shoulder). There were no humeral component failures. According to the criteria of Neer et al., the functional result was rated as excellent in three shoulders, satisfactory in six, and unsatisfactory in eight. CONCLUSIONS: Despite the finding that eight shoulders had an unsatisfactory functional result at the time of longterm follow-up, corticocancellous grafting of the glenoid successfully restored glenoid version and volume in fourteen of the seventeen shoulders in the present study. Patients with glenoid deficiency often have associated glenohumeral instability, which may affect the results of total shoulder arthroplasty. Bone-grafting of the glenoid is a technically demanding procedure that can restore bone stock in patients with structural defects.     

Anteroinferior bone-grafting can restore stability in osseous glenoid defects

BACKGROUND: Glenohumeral instability associated with a large osseous defect of the glenoid can be treated with bone graft to restore the glenoid concavity. The shape and positioning of the graft is critical: a graft that encroaches on the extrapolated glenoid curvature can prevent the head from seating completely in the glenoid, whereas a graft that is too far from the curvature does not restore the glenoid concavity. The purpose of the present study was to investigate how the intrinsic stability that is provided by the glenoid is affected by (1) a standardized anteroinferior glenoid defect and (2) different configurations of anteroinferior glenoid bone graft. METHODS: The anteroinferior stability provided by the glenoid was quantitated by measuring the balance stability angle in that direction. The balance stability angle is the maximal angle that the direction of the net humeral joint-reaction force can make with the glenoid centerline before dislocation takes place. The anteroinferior stability was assessed in each of four fresh-frozen, grossly normal cadaveric glenoids in (1) the unaltered state, (2) after the creation of a standardized defect of a magnitude that has been reported by other investigators to be sufficient to require a bone graft, and (3) after each step of a series of bone-grafting procedures involving grafts of varying height and contour. RESULTS: The anteroinferior glenoid defect significantly diminished the anteroinferior stability by almost 50% (p = 0.006). Bone-grafting significantly increased the stability provided by the glenoid. The increase in stability as compared with that of the glenoid with the standardized defect was particularly marked for contoured graft heights of 6 and 8 mm, for which the increases were 150% (p = 0.0001) and 229% (p < 0.00025), respectively. Contouring of the graft minimized the potential for unwanted contact between the ball and the graft. CONCLUSIONS: Anteroinferior shoulder instability caused by an osseous defect in the glenoid can be corrected with bone-grafting. The effectiveness of the graft in restoring the lost stability is related both to its height and to the extent to which it is contoured as long as the graft is not so prominent that it forces the ball posteriorly from the center of the glenoid.     

Superior glenoid inclination and glenoid bone loss

Correct anatomical alignment of the glenoid component is of central importance for wear and loosening in shoulder endoprostheses. The aim of this article is to review and clarify the biomechanical and clinical effects of incorrect glenoid inclination in reverse and anatomical joint replacements. Based on the literature and on our own work, statements are made about the following: (1) the glenoid inclination of a normal glenoid, a degenerative glenoid and a glenoid implant, and the consequences if superior inclination is too large, and (2) the surgical technique as well as tips and tricks for correct adjustment of the inclination. The inclination of the glenoid plane is a morphological parameter of the scapula with high individual variation and is best measured using reformatted computed tomography using three-dimensional software for reconstruction and evaluation. The standard value is between 0 and 10°. Excessive superior inclination promotes translation of the humeral head and the formation of rotator cuff tears—in a degenerative glenoid, to superior wear. The correct amount of superior inclination of the glenoid component is essential for the survival of the implant. Positioning without excessive superior inclination is therefore mandatory. Precise preoperative determination of glenoid inclination and wear is important in order to correctly plan the positioning of an implant. This serves as the basis for deciding whether a bone graft or patient-specific instrumentation is necessary. Thus, the surgeon also has prognostic parameters for the anticipation of possible complications as a result of the bone defect and abnormal orientation. However, the evaluation must always include the position of the scapula in these considerations.     

Patient positioning for shoulder arthroscopy based on variability in lateral acromion morphology

The purpose of this article is to highlight the variability among shoulders in the relationship between the lateral acromion and the humeral head and to describe how this variability may influence a surgeon’s choice of patient positioning for shoulder arthroscopy. In cases of increased lateral coverage of the humeral head by the acromion, arthroscopic access to the superior aspect of the glenoid through lateral portals becomes increasingly difficult because of a narrowed corridor of approach. Placing the ipsilateral arm in traction will lower the station of the humeral head and widen the arthroscopic corridor of approach to the superior labrum. Based on preoperative assessment of lateral acromion morphology, if the surgeon determines that inferior displacement of the humeral head of 25% or more of the humeral head diameter will be necessary to achieve adequate arthroscopic accessibility of the superior glenoid through lateral portals, we recommend the lateral decubitus position with continuous traction on the ipsilateral arm over the beach-chair position.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 5 (May-June), 2002: pp 547–549     

Effects of biceps tension and superior humeral head translation on the glenoid labrum

We sought to understand the effects of superior humeral head translation and load of the long head of biceps on the pathomechanics of the superior glenoid labrum by predicting labral strain. Using micro‐CT cadaver images, a finite element model of the glenohumeral joint was generated, consisting of humerus, glenoid bone, cartilages, labrum, and biceps tendon. A glenohumeral compression of 50 N and biceps tensions of 0, 22, 55, and 88 N were applied. The humeral head was superiorly translated from 0 to 5 mm in 1‐mm increments. The highest labral strain occurred at the interface with the glenoid cartilage and bone beneath the origin of the biceps tendon. The maximum strain was lower than the reported failure strain. The humeral head motion had relatively greater effect than biceps tension on the increasing labral strain. This supports the mechanistic hypothesis that superior labral lesions result mainly from superior migration of the humeral head, but also from biceps tension. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1424–1429, 2014.     

A novel surgical procedure for osteonecrosis of the humeral head: reposition of the joint surface and bone engraftment.

A novel surgical procedure was performed on a 33-year-old woman with idiopathic osteonecrosis of the head of the left humerus. The operation involved repositioning of the joint cartilage and bone engraftment through her humeral head from under the greater tuberosity with shoulder arthroscopy. The patient wore an abduction brace for 8 weeks after the operation to hold the joint surface in its new position. This surgical procedure resulted in considerable improvement of the functional status of the shoulder by relieving pain and increasing range-of-motion. A preoperative radiograph showed stage IV osteonecrosis of the humeral head. However, at follow-up, repositioning of the joint surface and improvement of the necrotic bone were observed by radiography and magnetic resonance imaging.     

Bone Grafting Severe Glenoid Defects in Revision Shoulder Arthroplasty

During revision total shoulder arthroplasty, bone grafting severe glenoid defects without concomitant reinsertion of a glenoid prosthesis may be the only viable reconstructive option. However, the fate of these grafts is unknown. We questioned the durability and subsidence of the graft and the associated clinical outcomes in patients who have this procedure. We retrospectively reviewed 11 patients with severe glenoid deficiencies from aseptic loosening of a glenoid component who underwent conversion of a total shoulder arthroplasty to a humeral head replacement and glenoid bone grafting. Large cavitary defects were grafted with either allograft cancellous chips or bulk structural allograft, depending on the presence or absence of glenoid vault wall defects, without prosthetic glenoid resurfacing. Clinical outcomes (Penn Shoulder Score, maximum 100 points) improved from 23 to 57 at a minimum 2-year followup (mean, 38 months; range, 24-73 months). However, we observed substantial graft subsidence in all patients, with eight of 11 patients having subsidence greater than 5 mm; the magnitude of graft resorption did not correlate with clinical outcome scores. Greater subsidence was seen with structural than cancellous chip allografts. Bone grafting large glenoid defects during revision shoulder arthroplasty can improve clinical outcome scores, but the substantial resorption of the graft material remains a concern. LEVEL OF EVIDENCE: Level III Prognostic study.     

Total shoulder arthroplasty: Some considerations related to glenoid surface contact

The area of prosthetic surface contact is an important surgeon-controlled variable in total shoulder arthroplasty and is related to the geometry of the glenoid and humeral articular surfaces and their relative positions. This study explores some of the factors that affect joint surface contact area. We measured the humeral and the glenoid articular surface angles in the superior-inferior and anteroposterior planes for two prosthesis systems representative of those in common clinical use. On the basis of these data we determined the range of glenohumeral positions providing full glenoid surface contact, a condition in which all of the articular surface of the glenoid component is in contact with the articular surface of the humeral component. We found a wide variability in the range of glenohumeral positions providing full glenoid contact with different prosthetic combinations. Some combinations do not even offer full glenoid surface contact with the joint in the centered position, for example, when the center of the humeral head articular surface is opposed to the center of the glenoid articular surface. The maximal range of glenohumeral positions providing full glenoid surface contact was 117° for a combination with a small radius of head curvature and a large articular surface angle. The relative positions of the humeral and glenoid articular surfaces also have a major influence on the joint contact area. Some combinations offer full glenoid surface contact only in a position of humeral abduction with respect to the scapula. Loss of full glenoid surface contact between the glenoid and humerus may allow for unwanted translations of the humeral head on the glenoid in the direction where contact is lacking. Furthermore, in positions where full surface contact is lacking, humeral bone or soft tissue may make unwanted contact with the glenoid. These results suggest that the design of the humeral articular surface and the surgical procedure should maximize full glenoid surface contact in functionally important positions.     

Muscle pedicled bone graft in revascularization of aseptic necrosis of the humeral head

A deltoid muscle-pedicled bone graft was used to treat avascular necrosis of the humeral head. Eighteen months later there was evidence of clinical improvement of the joint function, and plain x-rays and tomography showed signs of graft fusion in the recipient bed with reorganization of the formerly necrotic bone matrix in the humeral head.