Humeral hemiarthroplasty with biologic resurfacing of the glenoid for glenohumeral arthritis. Surgical technique

Pyrocarbon hemiprostheses show little glenoid erosion and good clinical function at 5.5 years of follow-up

BACKGROUND

The success of traditional shoulder hemiarthroplasty (HA) with cobalt-chromium heads is limited by painful glenoid erosion with problematic bone loss. Hemiprostheses with pyrolytic carbon (PyC) heads have shown reduced glenoid erosion in experimental laboratory studies. Few in vivo data are available.

METHODS

We performed a single-center consecutive cohort study of 31 of 34 patients (91%) who underwent PyC HA between September 2013 and June 2018. In 11 of these patients, concentric glenoid reaming was additionally performed. The mean follow-up period was 5.5 years (range, 3.5-7 years). Standardized radiographs were taken, and clinical function (Constant score) and pain (visual analog scale score) were recorded. Anteroposterior radiographs were analyzed according to an established method by 2 independent observers: A line parallel to the superior and inferior glenoid rim was translated to the most medial point of the glenoid surface. A further parallel line was placed on the spinoglenoid notch. The distance between these 2 lines was measured. Measurements were scaled using the known diameter of the implanted humeral head component. To assess eccentric erosion, anteroposterior and axial images were classified according to Favard and Walch, respectively.

RESULTS

Mean medial glenoid erosion measured 1.4 mm at an average of 5.5 years of follow-up. In the first year, 0.8 mm of erosion was observed, significantly more than the average erosion per year of 0.3 mm (P < .001). Mean erosion per year was 0.4 mm in patients with glenoid reaming vs. 0.2 mm in those without reaming (P = .09). An evolution of glenoid morphology was observed in 6 patients, of whom 4 had a progression of the erosion grade. The prosthesis survival rate was 100%. The Constant score improved from 45.0 preoperatively to 78.0 at 2-3 years postoperatively and 78.8 at latest follow-up (5.5 years postoperatively) (P < .001). The pain score on a visual analog scale decreased from 6.7 (range, 3-9) preoperatively to 2.2 (range, 0-8) at latest follow-up (P < .001). There was a weak correlation (r = 0.37) between erosion and pain improvement (P = .039) and no correlation between erosion and change in Constant score (r = 0.06).

CONCLUSION

PyC HA caused little glenoid erosion and a sustained improvement in clinical function in our cohort at mid-term follow-up. PyC demonstrates a biphasic development of glenoid erosion, with a reduced rate after the first year. PyC HA should therefore be considered as an alternative to cobalt-chromium HA and to anatomical total shoulder arthroplasty for patients with a high risk of glenoid component complications.

Poor evidence is used to support commercial payers' coverage policies for shoulder arthroplasty

BACKGROUND

The incidence of shoulder arthroplasty has continued to increase over the past decade. In response, commercial payers have implemented strategies to control the medical requirement of these surgeries in attempt to contain the growing costs. For example, most payers require a prolonged trial of conservative management prior to shoulder arthroplasty for patients who may otherwise be surgical candidates. However, little is known regarding the evidence used to support these indications. The purpose of this study was to analyze the references used by commercial payers to substantiate their coverage policies for shoulder arthroplasty.

METHODS

Ten of the leading commercial payers for total shoulder arthroplasty were identified. Publicly available coverage policies were searched on the internet or requested directly from the payer via email or telephone. Cited references were reviewed independently by two authors for type of document, level of evidence, and mention of the efficacy of conservative management.

RESULTS

A total of 5 coverage policies were obtained with 118 references. The most common reference type was primary journal article (n = 70; 59.3%) followed by review or expert opinion articles (n = 35; 29.7%). Most references were of level IV evidence (n = 60; 52.2%), with only 6 (5.2%) of level I or II evidence. Only 4 (3.5%) references mentioned the efficacy of conservative management in patients who may be candidates for shoulder arthroplasty.

CONCLUSION

The majority of references used to substantiate the coverage policies for shoulder arthroplasty among major commercial payers within the United States are of low scientific evidence and fail to demonstrate the success of required nonoperative intervention strategies. Our study underscores the need for high-quality, comparative trials that evaluate the outcomes of conservative management vs. shoulder arthroplasty in end-stage glenohumeral osteoarthritis patients in order to determine the most cost-effective treatment algorithm.

Glenoid wear and its impact on clinical results after humeral head replacement using a single prosthesis in cuff tear arthropathy with more than 8 years of follow-up

BACKGROUND

Glenoid wear (GW) is a long-term complication after humeral head replacement (HHR) and is one of the major reasons for revision surgery. This study aimed to evaluate GW at >8 years of follow-up after HHR in patients with cuff tear arthropathy (CTA) by use of a modified classification of GW, to examine the relationship between GW and clinical outcomes, and to identify risk factors for GW progression.

METHODS

This retrospective case-series study included 34 shoulders that were monitored for >8 years after HHR in patients with CTA (13 men and 21 women; mean age at surgery, 70.9 years [range, 55-82 years]). Patients were monitored for a mean of 10.3 years (range, 8.1-13.2 years). GW was classified using plain radiographs as follows: grade 0, no remarkable postoperative changes; grade 1, postoperative glenohumeral joint space narrower than preoperative glenohumeral joint space; grade 2, contact between glenoid and humeral head prosthesis; and grade 3, glenoid erosion. Grade 3 cases were further classified into the following subtypes: grade 3A, partial erosion of anterior glenoid; grade 3B, partial erosion of superior glenoid; and grade 3C, concentric erosion of glenoid. Clinical outcomes including range of motion (active flexion and active external rotation) and postoperative pain (Constant score) were compared between grade 0-2 shoulders and grade 3 shoulders, as well as between the grade 3 subtypes. Age, sex, preoperative range of motion, preoperative pain, and number of ruptured tendons were analyzed as possible risk factors for progression to grade 3.

RESULTS

The final GW grade was grade 0 in 3 shoulders, grade 1 in 10, grade 2 in 6, and grade 3 in 15 (grade 3A in 2, grade 3B in 6, and grade 3C in 7). The grade 3 group had lower pain scores (10.7 ± 6.2 vs. 14.2 ± 1.9, P = .044) and limited active flexion (108.2° ± 42.3° vs. 140.6° ± 26.7°, P = .041) compared with the grade 0-2 group. Subtype comparison showed that the grade 3B group had lower pain scores (7.0 ± 6.7 vs. 15.0 ± 0.0, P = .007) and limited active flexion (80.0° ± 26.2° vs. 140.8° ± 27.5°, P = .010) compared with the grade 3C group. Limited preoperative active external rotation was an individual risk factor for grade 3 GW (odds ratio, 0.93; 95% confidence interval, 0.88-0.99; P = .009).

CONCLUSIONS

In the long term (>8 years) after HHR with tendon transfer in patients with CTA, patients with the development of grade 3C GW ultimately achieve pain relief even without revision surgery whereas grade 3B GW is associated with persistent pain and might require revision surgery.

Mid- to long-term follow-up of shoulder arthroplasty for primary glenohumeral osteoarthritis in patients aged 60 or under

BACKGROUND

Shoulder arthroplasty in young patients with primary glenohumeral osteoarthritis is an area of continued controversy.

METHODS

A retrospective multicenter study was performed for all patients aged 60 years or less undergoing either hemiarthroplasty (HA) or total shoulder arthroplasty (TSA) for primary glenohumeral osteoarthritis with a minimum of 24-month follow-up. Clinical and functional outcomes, complications, and need for revision surgery were analyzed. Survivorship analysis using revision arthroplasty as an endpoint was determined.

RESULTS

A total of 202 patients with a mean age of 55.3 years (range, 36-60 years) underwent TSA with a mean follow-up of 9 years (range, 2-24.7 years). Revision arthroplasty was performed in 33 (16.3%) shoulders, with glenoid failure associated with the revision in 29 shoulders (88%). TSA survivorship analysis demonstrated 95% free of revision at 5 years, 83% at 10 years, and 60% at 20-year follow-up. A total of 31 patients with a mean age of 52.5 years (range, 38-60 years) underwent HA with a mean follow-up of 8.7 years (range, 2-21.4 years). Revision arthroplasty was performed in 5 (16.1%) shoulders, with glenoid erosion as the cause for revision in 4 shoulders (80%). HA survivorship analysis demonstrated 84% free from revision at 5 years and 79% at the final follow-up. TSA resulted in a significantly better range of motion, pain, subjective shoulder value, and Constant score compared with HA.

CONCLUSION

In young patients with primary glenohumeral osteoarthritis, TSA resulted in significantly better functional and subjective outcomes with no significant difference in longitudinal survivorship compared with patients treated with HA.

Optimal management of glenohumeral osteoarthritis

Glenohumeral osteoarthritis (OA) is defined as progressive loss of articular cartilage, resulting in bony erosion, pain, and decreased function. This article provides a gross overview of this disease, along with peer-reviewed research by experts in the field. The pathology, diagnosis, and classification of this condition have been well described. Treatment begins with non-operative measures, including oral and topical anti-inflammatory agents, physical therapy, and intra- articular injections of either a corticosteroid or a viscosupplementation agent. Operative treatment is based on the age and function of the affected patient, and treatment of young individuals with glenohumeral OA remains controversial. Various methods of surgical treatment, ranging from arthroscopy to resurfacing, are being evaluated. The roles of hemiarthroplasty, total shoulder arthroplasty, and reverse shoulder arthroplasty are similarly reviewed with supporting data.

Glenohumeral kinematics after soft tissue interposition graft and glenoid reaming: A cadaveric study

BACKGROUND

The management of young patients with glenohumeral arthritis is controversial. Resurfacing of the glenoid with biologic interposition and reaming of the glenoid have been suggested as potential treatment options. The goal of this study was to determine the change in glenohumeral contact pressures in interposition arthroplasty, as well as glenoid reaming in an arthritis model. We hypothesized that interposition with meniscal allograft will lead to the best normalization of contact pressure throughout the glenohumeral range of motion.

MATERIALS AND METHODS

Eight fresh-frozen cadaveric shoulders were tested in static positions of humeral abduction with a compressive load. Glenohumeral contact area, contact pressure, and peak force were determined sequentially for (1) intact glenoid (2) glenoid with cartilage removed (arthritis model) (3) placement of lateral meniscus allograft (4) placement of Achilles allograft (5) arthritis model with reamed glenoid.

RESULTS

The arthritis model demonstrated statistically higher peak pressures than intact glenoid and glenoid with interpositional allograft. Meniscal and Achilles allograft lowered mean contact pressure and increased contact area to a level equal to or more favorable than the control state. In contrast, the reamed glenoid did not show any statistical difference from the arthritis model for any of the recorded measures.

CONCLUSION

Glenohumeral contact pressure is significantly improved with interposition of allograft at time zero compared to an arthritic state. Our findings suggest that concentric reaming did not differ from the arthritic model when compared to normal. These findings favor the use of allograft for interposition as a potential treatment option in patients with glenoid wear.

Osteochondral Biopsy Analysis Demonstrates That BST-CarGel Treatment Improves Structural and Cellular Characteristics of Cartilage Repair Tissue Compared With Microfracture

OBJECTIVE

The efficacy and safety of BST-CarGel, a chitosan-based medical device for cartilage repair, was compared with microfracture alone at 1 year during a multicenter randomized controlled trial (RCT) in the knee. The quality of repair tissue of osteochondral biopsies collected from a subset of patients was compared using blinded histological assessments.

METHODS

The international RCT evaluated repair tissue quantity and quality by 3-dimensional quantitative magnetic resonance imaging as co-primary endpoints at 12 months. At an average of 13 months posttreatment, 21/41 BST-CarGel and 17/39 microfracture patients underwent elective second look arthroscopies as a tertiary endpoint, during which ICRS (International Cartilage Repair Society) macroscopic scoring was carried out, and osteochondral biopsies were collected. Stained histological sections were evaluated by blinded readers using ICRS I and II histological scoring systems. Collagen organization was evaluated using a polarized light microscopy score.

RESULTS

BST-CarGel treatment resulted in significantly better ICRS macroscopic scores (P = 0.0002) compared with microfracture alone, indicating better filling, integration, and tissue appearance. Histologically, BST-CarGel resulted in a significant improvement of structural parameters-Surface Architecture (P = 0.007) and Surface/Superficial Assessment (P = 0.042)-as well as cellular parameters-Cell Viability (P = 0.006) and Cell Distribution (P = 0.032). No histological parameters were significantly better for the microfracture group. BST-CarGel treatment also resulted in a more organized repair tissue with collagen stratification more similar to native hyaline cartilage, as measured by polarized light microscopy scoring (P = 0.0003).

CONCLUSION

Multiple and independent analyses in this biopsy substudy demonstrated that BST-CarGel treatment results in improved structural and cellular characteristics of repair tissue at 1 year posttreatment compared with microfracture alone, supporting previously reported results by quantitative magnetic resonance imaging.

Shoulder arthroplasty options in young (<50 years old) patients: review of current concepts

BACKGROUND

Prosthetic shoulder arthroplasty provides excellent pain relief and functional restoration for patients with glenohumeral arthritis, but concerns of survivorship have limited its use in younger patients.

DISCUSSION

Despite general reports of high long-term survivorship, implant failure and functional deterioration after total shoulder arthroplasty are major concerns in the management of younger patients. In addition to having a longer life expectancy, younger patients also tend to be more active and can be expected to place greater demands on their shoulder arthroplasty.

CONCLUSION

Alternative strategies have been developed and used for shoulder arthroplasty in younger patients. This manuscript reviews current concepts of shoulder arthroplasty in young patients.

The high failure rate of biologic resurfacing of the glenoid in young patients with glenohumeral arthritis

BACKGROUND

The current study evaluated the outcomes of biologic resurfacing of the glenoid using a lateral meniscus allograft or human acellular dermal tissue matrix at intermediate-term follow-up.

METHODS

Forty-five patients (mean age, 42.2 years) underwent biologic resurfacing of the glenoid, and 41 were available for follow-up at a mean of 2.8 years. Lateral meniscal allograft resurfacing was used in 31 patients and human acellular dermal tissue matrix interposition in 10. Postoperative range of motion and clinical outcomes were assessed at the final follow-up.

RESULTS

The overall clinical failure rate was 51.2%. The lateral meniscal allograft cohort had a failure rate of 45.2%, with a mean time to failure of 3.4 years. Human acellular dermal tissue matrix interposition had a failure rate of 70.0%, with a mean time to failure of 2.2 years. Overall, significant improvements were seen compared with baseline with respect to the visual analog pain score (3.0 vs. 6.3), American Shoulder and Elbow Surgeons score (62.0 vs. 36.8), and Simple Shoulder Test score (7.0 vs. 4.0). Significant improvements were seen for forward elevation (106° to 138°) and external rotation (31° to 51°).

CONCLUSION

Despite significant improvements compared with baseline values, biologic resurfacing of the glenoid resulted in a high rate of clinical failure at intermediate follow-up. Our results suggest that biologic resurfacing of the glenoid may have a minimal and as yet undefined role in the management of glenohumeral arthritis in the young active patient over more traditional methods of hemiarthroplasty or total shoulder arthroplasty.

The Mature Athlete's Shoulder

CONTEXT

The mature athlete's shoulder remains a challenging clinical condition to manage. A normal natural history of the shoulder includes stiffness, rotator cuff tears, and osteoarthritis, all of which can become increasingly more symptomatic as an athlete ages.

EVIDENCE ACQUISITION

PubMed (1978-2013).

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 3-4.

RESULTS

Rotator cuff pathology increases with age and activity level. Partial tears rarely heal, and debridement of significant partial tears results in poorer outcomes than those of repair. Repair of partial-thickness tears can be accomplished with completion and subsequent repair or in situ repair. The most successful result for treatment of osteoarthritis in the shoulder remains total shoulder arthroplasty, with more than 80% survival at 20 years and high rates of return to sport. Caution should be taken in patients younger than 60 years, as they show much worse results with this treatment. Adhesive capsulitis of the shoulder can be successfully treated with nonoperative management in 90% of cases.

CONCLUSION

Mature athletes tend to have rotator cuff pathology, osteoarthritis, and stiffness, which may limit their participation in athletic events. Age is a significant consideration, even within the "mature athlete" population, as patients younger than 50 years should be approached differently than those older than 65 years with regard to treatment regimens and postoperative restriction.

Foreign body reaction to acellular dermal matrix allograft in biologic glenoid resurfacing

BACKGROUND

Biologic glenoid resurfacing is a treatment option for young patients with glenohumeral arthritis. An optimal synthetic graft for glenoid resurfacing should allow repopulation with host cells, be durable enough to tolerate suture fixation and forces across the joint, and present no host inflammatory response. We report two cases of giant cell reaction to GraftJacket(®) after biologic glenoid resurfacing.

CASE DESCRIPTION

Two patients who underwent hemiarthroplasty and biologic glenoid resurfacing using GraftJacket(®) had a foreign body giant cell reaction that required revision surgery. Intraoperatively, both patients were observed to have a well-fixed humeral component and a dense, erythematous, synovitic membrane overlying the glenoid. Pathology specimens showed a benign reactive synovium, chronic inflammation, and foreign body giant cell reaction. After débridement and conversion to total shoulder arthroplasty, both patients continued to be pain-free at greater than 1-year followup.

LITERATURE REVIEW

Multinucleated giant cell and mononuclear cell responses have been observed in an animal model after use of GraftJacket(®). Although the use of acellular matrix-based scaffold for biologic glenoid resurfacing is not new, the possibility of foreign body reaction as a source of persistent symptoms has not been described.

CLINICAL RELEVANCE

Given the lack of data to indicate an advantage to biologic resurfacing of the glenoid over hemiarthroplasty alone, resurfacing should not introduce significant additional surgical complications. We suggest foreign body reaction be considered in the differential diagnosis for a persistently painful shoulder after biologic glenoid resurfacing using an acellular allograft patch.

Geometrical analysis results of 42 resurfacing shoulder prostheses: A CT scan study

BACKGROUND

Shoulder resurfacing arthroplasty was introduced in Scandinavia in the early 1980s then developed by SA Copeland.

HYPOTHESIS

Resurfacing prostheses restore the normal anatomy of the proximal humerus. Here, our objective was to evaluate humeral resurfacing prosthesis position on radiographs and computed tomography (CT) images.

MATERIALS AND METHODS

We retrospectively reviewed 42 consecutive cases seen at a single centre between 2004 and 2009. Mean patient age was 65 years. CT was performed routinely before prosthesis implantation and at re-evaluation. The Copeland Mark III(®) (Biomet France SARL, 26903 Valence, France) implant was used in 32 cases and the Aequalis Resurfacing Head(®) (Tornier France, 38334 Saint-Ismier, France) in 10 cases. The post-implantation CT images were used to measure the angle of inclination, medial humeral offset, lateral glenohumeral offset, and version of the implant.

RESULTS

Mean follow-up was 18 months. Compared to baseline, no significant changes were found at re-evaluation for the angle of inclination or lateral glenohumeral offset. In contrast, medial humeral offset increased by 3.47mm, and excessive anteversion of 4.23° compared to the bicondylar line was noted.

DISCUSSION

Humeral head resurfacing prostheses restore the overall anatomy of the proximal humeral head. Our CT scan evaluation protocol seems reproducible and enables an evaluation of implant geometry. In our experience, resurfacing arthroplasty restored the native humeral offset. Inadequate retroversion was noted and was probably related to insufficient exposure during surgery.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Osteochondral glenoid allograft for biologic resurfacing of the glenoid: biomechanical comparison of novel design concepts

INTRODUCTION

Biologic resurfacing of the glenoid has hitherto failed to adequately restore the geometry and biology of the glenoid. We hypothesised that a new concept for a press-fit osteochondral allograft glenoid replacement would restore the anatomic geometry of the glenoid, with primary stability guaranteed by the construct through press-fit fixation alone.

MATERIAL AND METHODS

Five sawbone models of human scapulae and 5 models using sheep scapulae were prepared for testing of 3 different interface designs (cross, rectangle, and dovetail). Micromotion at the graft interface was assessed in response to 1000 cycles of 30 N shear and 100 N compressive load, and maximal craniocaudal force was determined under 500 N compressive load.

RESULTS

In sawbones, mean (range) micromotion ranged from 38 (13-88) μm for cross to 208 (89-335) μm for rectangle, and decreased to 29 (21-57) μm for cross to 104 (34-127) μm for rectangle after 1000 cycles of applied shear force. In sheep bone, the mean (range) of micromotion was 15 (9-22) μm for dovetail to 51 (10-503) μm for cross and decreased to 15 (10-20) μm for dovetail to 44 (24-199) μm for cross; after 1000 cycles with the rectangle design, it decreased from 32 (25-217) μm to 16 (9-143) μm.

DISCUSSION

Despite biomechanical differences, in vitro allograft stability was generally adequate for all tested designs, particularly after the graft was allowed to "seat" by repetitive loading. While various geometries are potentially candidates for press-fitting a glenoid allograft to a host scapula, a rectangular interface between graft and host provided a favorable combination of both technical feasibility and biomechanical reliability.

CONCLUSION

The concept of an osteochondral glenoid allograft for glenoid reconstruction is technically feasible and demonstrates adequate primary stability in vitro.

A quantitative method for determining medial migration of the humeral head after shoulder arthroplasty: preliminary results in assessing glenoid wear at a minimum of two years after hemiarthroplasty with concentric glenoid reaming

HYPOTHESIS

Glenoid erosion and medial migration of the humeral head prosthesis have been observed after most types of shoulder arthroplasty. A method of measuring the change in humeral head position with time after shoulder prosthetic arthroplasty was applied it to 14 shoulders that underwent humeral hemiarthroplasty with concentric glenoid reaming. We hypothesized that the measurement technique would be reproducible and that the rate of wear would be small in the series of shoulders studied.

MATERIALS AND METHODS

Standardized anteroposterior and axillary radiographs were obtained after surgery. Two examiners measured the position of the humeral head center in relation to scapular reference coordinates for the anteroposterior and axillary projections and plotted these values against time after surgery. The change in position was characterized as the slope of this plot. Shoulders were included if there were at least 3 sets of postoperative films, the last being at least 2 years after surgery.

RESULTS

The slopes measured by the 2 examiners agreed within 0.5 mm/y for the anteroposterior and the axillary projections. For the series of shoulder arthroplasties, the rate of movement of the head center toward the scapula was less than 0.4 mm/y for either examiner in either projection.

DISCUSSION

Medial migration is a concern after any type of shoulder arthroplasty, whether a hemiarthroplasty, a biological interpositional arthroplasty, or a total shoulder arthroplasty. Quantifying the rate of medial migration over time after shoulder arthroplasty is an important element of clinical follow-up.

CONCLUSIONS

This is an inexpensive, practical, and reproducible method that can be used to determine the rate of medial migration of the humeral head on plain radiographs after shoulder arthroplasty. The average rate of medial migration in the shoulders in this study was small.

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.

Case reports: two cases of glenohumeral chondrolysis after intraarticular pain pumps

BACKGROUND

Acute idiopathic chondrolysis in young adults is rare. The etiology often is unknown and outcomes can be devastating owing to rapid development of painful secondary osteoarthritis. There have been some recent reports of chondrolysis after arthroscopic shoulder procedures. Animal and laboratory data suggest chondrolysis is related to the use of intraarticular pain pumps, although there is no conclusive evidence that this is causative in patients.

CASE DESCRIPTION

We present two cases of young adults with chondrolysis of the humeral head after intraarticular pain pump use with humeral head resurfacing and biologic glenoid resurfacing.

LITERATURE REVIEW

Several authors report glenohumeral chondrolysis after shoulder arthroscopy involving the use of bupivacaine pain pumps. In addition, experimental animal studies have confirmed the presence of chondrolysis after bupivacaine infusion.

PURPOSES AND CLINICAL RELEVANCE

These cases provide additional evidence of an important association between postarthroscopic chondrolysis of the glenohumeral joint and the use of bupivacaine pain pumps.