Glenoid revision is best treated with glenoid implants: Opposes

Glenoid component loosening is a common cause of failure for anatomic total shoulder arthroplasty. Revision options include reimplantation of an anatomic total shoulder, conversion to a reverse shoulder arthroplasty, or bone graft of the glenoid defect alone. In the presence of an intact rotator cuff with significant glenoid bone loss, the most predictable revision option is bone graft of the glenoid defect alone. Recent studies have demonstrated good clinical outcomes and a lower complication and re-revision rate with bone graft alone compared to attempted glenoid component reimplantation.     

Symptomatic Glenoid Loosening Complicating Total Shoulder Arthroplasty

Glenoid component loosening is one of the most common causes of failed total shoulder arthroplasty. Previous reports indicate that it is desirable to reimplant the glenoid component during revision shoulder arthroplasty. The purpose of our study was to retrospectively evaluate the satisfaction of patients undergoing glenoid revision (reimplantation or resection) following total shoulder replacement specifically for symptomatic glenoid loosening. Twenty-eight shoulders that developed symptomatic glenoid loosening following primary total shoulder arthroplasty were included in the study. Patients were retrospectively evaluated at a minimum of 2 years postoperatively. Patients either underwent resection followed by reimplantation of the glenoid component (13) or resection of the component with or without bone grafting (15). Each patient was evaluated with the UCLA Shoulder Scale and the Constant–Murley Shoulder Assessment. There were seven excellent, 13 good, five fair and three poor results on the UCLA score. Functional outcome scores trended higher in the reimplantation group but were not statistically significant. Both groups reported equal pain relief and satisfaction. Five out of 15 patients underwent arthroscopic resection of the glenoid, and these patients scored as well on the UCLA and Constant scores as the reimplantation group. When symptomatic glenoid loosening is the indication for revision total shoulder replacement, patients tend to achieve good to excellent results. Though functional scores were slightly higher in the reimplantation group, satisfaction was equally high in both groups. Resection, when indicated, should be performed arthroscopically as this improved functional outcome in our series.     

Glenoid revision is best treated with glenoid implants: Affirms

Radiographic lucency adjacent to the glenoid component is a common finding after a total shoulder arthroplasty. In fact, the majority of patients with this entity are asymptomatic and require no management. However, when there is documented progression of lucent lines, leading to clinically symptomatic loosening, revision total shoulder arthroplasty is warranted. Treatment options for revision surgery are guided by the amount of glenoid bone loss and include either reimplanation or removal. When feasible, reimplantation of the glenoid yields superior clinical results. Reimplantation strategies include reimplantation without bone grafting, one-stage reimplantation with bone grafting, two-stage reimplantation with bone grafting, and reimplantation with the use of glenoid augments. If bone loss precludes, the clinician may consider implant removal with either biologic resurfacing or hemiarthroplasty.     

Total shoulder arthroplasty — current problems and possible solutions

The concept and design of a cemented unconstrained total shoulder arthroplasty (TSA), introduced by Charles Neer II 25 years ago, has been successful in the management of degenerative and inflammatory conditions of the shoulder, controlling pain and, in many patients, significantly improving function. The clinical outcome is very much determined by the nature and severity of the pathology, as well as by the surgeon's experience and ability to correctly locate and fix the components. Total shoulder arthroplasty is a technically difficult procedure with perhaps a greater potential for technical errors and complications compared with other commonly performed arthroplasties. Current systems are modular on the humeral side, with varying head diameters and neck lengths, allowing more accurate coverage of the cut surface of the humeral neck and improved ability to establish the position of the joint line within the requirements of correct soft tissue tension and balance. Cemented all-polyethylene glenoid components remain the most favored, but the majority now have an increased radius of curvature compared with their corresponding humeral head, to allow translation during movement. Aseptic glenoid component loosening is the most frequently encountered long-term complication and is hastened by conforming prostheses, incorrect positioning, rotator cuff tears, and capsular contractures, but is protected by secure glenoid fixation. Cemented one-piece metal-backed glenoids have been disappointing, but non-cemented glenoids are being trialed with promising early results, although they have introduced their own particular problems of rapid polyethylene wear and component dissociation. Although cemented humeral components have a very low incidence of symptomatic loosening, most surgeons currently use press-fit designs supplemented with metaphyseal porous coating for osseous integration. Based on increased understanding of the morphology of the upper humerus, current designs are evolving with increased modularity, allowing the surgeon to choose the appropriate size, inclination, offset and version of the humeral component. These changes will, it is hoped, result in improved functional recovery and increased survivorship of the glenoid component. Received for publication on April 15, 1998; accepted on July 31, 1998     

Cuff tear arthropathy is best treated with a reverse total shoulder arthroplasty

Cuff tear arthropathy is the arthritic eroded collapse of the glenohumeral joint with progressive superior humeral migration in the setting of long-standing rotator cuff insufficiency. The ideal management of cuff tear arthropathy remains elusive. Current arthroplasty options include hemiarthroplasty or reverse shoulder arthroplasty. Proper clinical and radiographic evaluation is essential in decision making in order to optimize outcomes. Acromio-humeral distance (AHD), as measured on plain radiographs, as well as fatty degeneration of the rotator cuff muscles on MRI are reliable tools for decision making. AHD < 7 mm correlates well with complete tear of the supraspinatus while AHD < 5 mm indicates infraspinatus involvement with significant muscular atrophy. Hemiarthroplasty remains an option for providing pain relief; however, continued development of superior migration and glenoid erosion remains a concern. The conversion to reverse total shoulder arthroplasty after hemiarthroplasty can be difficult due to glenoid bone loss. Recent literature supports the use of reverse total shoulder arthroplasty over hemiarthroplasty for cuff tear arthropathy with significant differences in functional outcome. Here, we discuss the radiographic evaluation of cuff tear arthropathy and review the treatment options and why we advocate the use of the reverse prosthesis.     

Baseplate placement in failed total shoulder replacement: Builder’s choice

Glenoid component loosening has been recognized as one of the common indications for revision surgery after total shoulder arthroplasty. Replacement with a standard glenoid component is sometimes possible when bone loss is minimal and contained within the glenoid vault. If glenoid bone stock is poor, more complex revision strategies include bone graft reconstruction, custom implants, and the use of augmented components. Reverse total shoulder arthroplasty has also developed into a platform for revision surgery. However, surgeons must be aware that when used for revision, complication rates are higher and survival times are shorter. Glenoid revision is technically demanding even for an experienced shoulder surgeon and may lead to early revision failures if done improperly. Shoulder surgeons must have a detailed understanding of expected outcomes, proper indications and current bone grafting techniques when attempting glenoid reconstruction.     

Catastrophic failure of a low profile metal-backed glenoid component after total shoulder arthroplasty

Context:

The longevity of the glenoid component in total shoulder arthroplasty (TSA) continues to be problematic. All polyethylene glenoid components have been most widely used, but loosening rates with time and the need for revision has resulted in high-profile metal-backed components with the potential for a more stable prosthesis bone interface and liner exchange. High revision rates in the high profile metal backed designs led us to evaluate a low profile metal backed component.

Aims:

To examine the rate and mode of failure of a TSA in a single surgeon consecutive series that has been identified by the Australian National Joint Replacement Registry to have a higher than anticipated rate of revision.

Materials and Methods:

This is a single surgeon retrospective consecutive series of 51 arthroplasties undertaken in 50 patients (18 males and 32 females) with an average age of 70.4 ears (range 51-90) and mean follow-up of 5.5 years (range 3.7-8.1).

Results:

We observed a very high (29%) rate of revision of the metal-backed glenoid components in this series. The primary mode of failure was glenoid baseplate nonintegration which with a well-fixed central cage screw led to bone resorption and implant breakage or disassembly.

Conclusion:

Analysis of the mode of failure of implants identified by robust registries is essential for the development of new prostheses and the pursuit of prosthesis longevity. This low profile metal backed prosthesis has been withdrawn, but without a published mechanism of failure. We feel that any prosthesis withdrawal should be accompanied by appropriate published mechanisms to prevent future component design errors based on similar design problems.     

Comparison of mid-term outcomes of total shoulder arthroplasty for B2 and A glenoids treated with trabecular metal glenoid components

BackgroundTreatment of B2 glenoids in total shoulder arthroplasty (TSA) has been associated with worse clinical outcomes and increased rates of glenoid loosening. The purpose of this study was to describe and compare the mid-term outcomes of TSA using a trabecular metal-backed glenoid in patients with B2 and A glenoids.MethodsPatients who underwent anatomic TSA with a trabecular metal-backed glenoid component (second generation trabecular metal glenoid) for primary osteoarthritis and had minimum 5-year follow-up were reviewed. All patients underwent eccentric glenoid reaming to treat biconcavity, if present. Preoperative imaging was reviewed and patients were divided into 2 groups: Type A and Type B2. Mid-term outcome measures including patient-rated outcome scores (Patient Reported Outcome Measurement Information System and American Shoulder and Elbow Surgeons [ASES]) and shoulder range of motion were determined. ASES score was compared between groups. Radiographs were graded for radiolucent lines and posterior humeral head migration and evaluated for glenoid loosening.ResultsTwenty-two patients had Type A glenoids and 22 patients had B2 glenoids. Sixteen patients in the A group and 18 patients in the B2 group had full radiographic and physical exam follow-up. Both groups had similar follow-up (6.7 ± 1.1 years A, 6.6 ± 0.9 years B2, P = .88). Groups were similar in terms of age at surgery, gender distribution, body mass index, severity of medical comorbidities, and hand dominance distribution. The B2 patients had a mean preoperative glenoid retroversion of 17.5° ± 6.7° and posterior subluxation of 8.5% ± 5.3%. No patients in either group had evidence of glenoid loosening at follow-up. No patients required revision surgery. Nine of 16 in the A group had evidence of mild radiolucent lines (8 grade 1, 1 grade 2). Eight of 18 patients in the B2 group had mild radiolucencies (all grade 1). Two of 16 Type A and 6 of 18 B2 patients had evidence of posterior humeral migration, but all cases were graded as mild. Both groups had similar follow-up mean ASES scores (95.5 A, 89.0 B2, P = .25).ConclusionAt minimum 5-year follow-up, patients who underwent TSA with a trabecular metal-backed glenoid component demonstrated excellent clinical and patient-reported outcomes regardless of preoperative glenoid morphology (A or B2). No patients in either group had evidence of glenoid loosening or required revision surgery. These favorable mid-term outcomes of trabecular metal-backed glenoids in B2 deformities need to be followed longitudinally to determine long-term durability.Level of EvidenceLevel III; Retrospective Comparative Study     

Cemented polyethylene versus uncemented metal-backed glenoid components in total shoulder arthroplasty: a prospective,double-blind,randomized study

Thirty-nine patients (forty shoulders) with primary osteoarthritis consented to be randomized to receive either a cemented all-polyethylene glenoid component or a cementless metal-backed component at the time of total shoulder arthroplasty. Their mean age was 69 years. Preoperative and postoperative evaluations were completed at 3, 6, 12, 24, and 36 months by history, physical examination, radiographs, and Constant scoring system. The presence of periprosthetic radiolucent lines was significantly greater with polyethylene than with metal-backed glenoids (85% vs 25%, P <.01). Of 20 radiolucent lines, 12 (60%) around polyethylene glenoids were present on immediate postoperative radiographs and 25% were progressive. No significant correlation was found between the presence of radiolucent lines around polyethylene glenoids and functional results (P =.3). By contrast, periprosthetic radiolucent lines around metal-backed glenoids were rare but progressive when present. The incidence of loosening of metal-backed implants (4 cases, 20%) was significantly higher than that observed with polyethylene glenoids (0%, P <.001) and was associated with component shift and severe osteolysis. Metal-backed glenoid loosening significantly correlated with deteriorating functional results and increasing pain (P <.05). Revision surgery was required for 4 patients in the metal-backed group (P =.02), for a subscapularis tear (1 case) and metal-backed glenoid component loosening (3 cases). Computed tomography scan analysis and revision surgery revealed that preoperative posterior humeral subluxation may recur with time despite glenoid reorientation and may cause asymmetric accelerated polyethylene wear, resulting in metal-on-metal contact and severe osteolysis. Reimplantation of a stable cemented glenoid component was possible in 1 case, whereas the cavitary defect was packed with cancellous bone in the 2 other cases. At a minimum of 3 years' follow-up, the results of this study clearly show that (1) the survival rate of cementless, metal-backed glenoid components is inferior to cemented all-polyethylene components and (2) the incidence of radiolucency at the glenoid-cement interface with all-polyethylene components is high and remains a concern. The high rate of loosening, because of the absence of ingrowth and/or the accelerated polyethylene wear, has led us to abandon the use of metal-backed glenoids. Efforts must continue to improve glenoid component design and fixation.     

Systematic Review and Meta-Analysis of Locked Posterior Dislocation of the Shoulder Treated with Shoulder Arthroplasty: Improved Outcomes for Total Shoulder Arthroplasty are Associated with Increased Age

Locked shoulder dislocations account for up to 5% of shoulder dislocations. These relatively rare injuries are characterized by dislocation of the humeral head from the scapular glenoid cavity with the humeral head incarcerated on the glenoid in a “locked” fashion. Diagnosis is often delayed because of the complexity of clinical presentation and subtle radiographic findings, resulting in locking of the humeral head out of the glenoid cavity with severe functional deficits. Most commonly, there are bony injuries to the glenoid and humeral head that engage and prevent closed reduction. Since few patients present with this injury, evidence-based treatment guidelines have not been established. The objective of this review is to assess postoperative outcomes following shoulder arthroplasty for locked posterior shoulder dislocations (LPSD) to guide best practices for treatment. This systematic review was conducted following PRISMA guidelines, searching the PubMed and Web of Science databases for original articles assessing outcomes following arthroplasty for locked posterior shoulder dislocations. Seven publications that evaluated 102 patients were included. Additionally, nine case studies were included, assessing 20 shoulder arthroplasties. Overall, the analysis demonstrated significant improvement in shoulder pain following total shoulder arthroplasty (TSA) (P = 0.0003). Older operative patient ages for TSA resulted in significantly improved modified Neer outcomes scores and patient satisfaction compared to younger patients (P = 0.047). A positive correlation was noted for the duration of dislocation and necessity for revision surgery following hemiarthroplasty (HSA) and TSA combined and TSA separately. The risk ratios assessing the incidence of postoperative complications (RR = 0.56, 95% CI = 0.28–1.11) and necessity for revision surgery (RR = 0.58, 95% CI = 0.24–1.39) were insignificant but noted outcomes favoring TSA. Data from the included studies show that both TSA and HSA are efficacious at treating locked posterior shoulder dislocation. Postoperative outcomes following TSA versus HSA are similar. TSA may be a more efficacious surgical treatment in elderly patients, with improved outcomes and patient satisfaction scores compared to younger patients. Early diagnosis and treatment of posterior locked dislocations may lead to reduced postoperative complications and revision surgery, signaling the importance of proper injury investigation and early treatment. The role of RSA in the management of locked posterior shoulder dislocation remains to be determined, as there is insufficient clinical outcome data currently in the literature.     

Bone preserving technique for reverse arthroplasty: The preferred management option for osteoarthritis with glenoid bone loss in patients 70 and older

Elderly patients with shoulder arthritis and glenoid bone loss represent a challenging patient population. Surgical treatment options include hemiarthroplasty, anatomic total shoulder arthroplasty (TSA) with bone grafting or augmentation, and reverse total shoulder arthroplasty (RSA). The RSA has multiple advantages compared to anatomic TSA, particularly in an older patient population with glenoid bone loss.RSA with an augmented glenoid baseplate is ideal for the treatment of patients who have glenoid bone loss. The augmented base plate has many advantages including bone preservation, longer central and peripheral screws, ability to dial the augment to match the region of bone deficiency, and lateralization to improve tensioning on the deltoid and rotator cuff. Additionally, a bone preserving RSA is possible with an augmented glenoid baseplate in patients with no glenoid bone loss.     

Glenoid Reconstruction in Revision Shoulder Arthroplasty

Failed shoulder arthroplasty associated with glenoid bony deficiency is a difficult problem. Revision surgery is complex with unpredictable outcome. We asked whether revision shoulder arthroplasty with glenoid bone grafting could lead to good outcome. We retrospectively reviewed 21 patients who underwent glenoid bone grafting using corticocancellous bone grafting or impaction grafting using cancellous bone graft. Three patients underwent revision TSA, five patients hemiarthroplasty, 10 patients hemiarthroplasty with biologic resurfacing of the glenoid, and three patients revision to reverse TSA. The patients had minimum 25 months followup (average, 45 months; range, 25-92 months). All patients had improvement in their range of motion and the Constant-Murley score. Most improvement occurred in patients with glenoid reimplantation. Patients who underwent revision reverse TSA had improvement in shoulder flexion but decrease in external rotation motion. We conclude revision shoulder arthroplasty with glenoid bone grafting can produce good short-term outcome and glenoid component reinsertion should be attempted whenever possible.     

Periprosthetic humeral fracture after Copeland resurfacing and the role of revision arthroplasty: A report of three cases

Follow-up series of the Copeland resurfacing hemiarthroplasty have reported few postoperative fractures around the prosthesis. We report three cases of periprosthetic fracture around a Copeland resurfacing arthroplasty. Due to prosthetic loosening and tuberosity comminution, all cases were managed with revision shoulder arthroplasty. All patients had good functional outcome and range of movement on early follow-up.     

Surgical options for the young patient with glenohumeral arthritis

Young patients with glenohumeral arthritis are an ongoing treatment challenge. They typically have high demands of their shoulders, require long-term durability due to their young age, and often have altered local anatomy, through their disease process (instability arthropathy, juvenile rheumatoid arthritis, etc.) or from previous surgery (capsulorraphy arthropathy, chondrolysis, etc.). Workup to evaluate underlying causes of early arthritis, and to exclude infectious causes are necessary. When nonoperative management fails, arthroscopic debridement, hemiarthroplasty (isolated, with glenoid reaming, or with biological interposition), and total shoulder arthroplasty are treatment options available to the treating surgeon. Debridement or hemiarthroplasty can provide pain relief for a subset of patients, but results have not been reproducible across the literature and have not been durable over time. Total shoulder arthroplasty provides the most reliable pain relief, but long-term glenoid loosening and wear continue to lead to high revision rates in this patient population.     

Glenoidersatz bei Omarthrose

In anatomical shoulder arthroplasty glenoid replacement is a critical point. Although total shoulder arthroplasty (TSA) provides better functional and pain results than hemi shoulder arthroplasty (HSA) there is great reluctance to implant a glenoid. For successful glenoid replacement it is necessary to preoperatively evaluate clear indications for glenoid replacement. Planning is a crucial point and has to be done thoroughly. The gold standard is an all polyethylene cemented glenoid. The implantation technique is most important to obtain an excellent and long-term result without complications. Significant key factors are preservation of the subchondral bone and an anatomical reconstruction of the glenoid. It seems that after a period of 10 years the loosening rate of glenoids increases and revisions rates rise. Therefore there is a high demand to develop new implants and a need for improved and convertible glenoids with better modularity and alternative options for fixation.     

Prognostic Factors in Arthroplasty in the Rheumatoid Shoulder

Total shoulder arthroplasty is commonly considered a good option for treatment of the rheumatoid shoulder. However, when the rotator cuff and glenoid bone stock are not preserved, the clinical outcome of arthroplasty in the rheumatoid patients remains unclear. Aim of the study is to explore the prognostic value of multiple preoperative and peroperative variables in total shoulder arthroplasty and shoulder hemiarthroplasty in rheumatoid patients. Clinical Hospital for Special Surgery Shoulder score was determined at different time points over a mean period of 6.5 years in 66 rheumatoid patients with total shoulder arthroplasty and 75 rheumatoid patients with shoulder hemiarthroplasty. Moreover, radiographic analysis was performed to assess the progression of humeral head migration and glenoid loosening. Advanced age and erosions or cysts at the AC joint at time of surgery were associated with a lower postoperative Clinical Hospital for Special Surgery Shoulder score. In total shoulder arthroplasty, status of the rotator cuff and its repair at surgery were predictive of postoperative improvement. Progression of proximal migration during the period after surgery was associated with a lower clinical score over time. However, in hemiarthroplasty, no relation was observed between the progression of proximal or medial migration during follow-up and the clinical score over time. Status of the AC joint and age at the time of surgery should be taken into account when considering shoulder arthroplasty in rheumatoid patients. Total shoulder arthroplasty in combination with good cuff repair yields comparable clinical results as total shoulder arthroplasty when the cuff is intact.     

Mid-term results of a metal-backed glenoid component in total shoulder replacement

Total shoulder replacement is a successful procedure for degenerative or some inflammatory diseases of the shoulder. However, fixation of the glenoid seems to be the main weakness with a high rate of loosening. The results using all-polyethylene components have been better than those using metal-backed components. We describe our experience with 35 consecutive total shoulder replacements using a new metal-backed glenoid component with a mean follow-up of 75.4 months (48 to 154). Our implant differs from others because of its mechanism of fixation. It has a convex metal-backed bone interface and the main stabilising factor is a large hollow central peg. The patients were evaluated with standard radiographs and with the Constant Score, the Simple Shoulder Test and a visual analogue scale. All the scores improved and there was no loosening, no polyethylene-glenoid disassembly and no other implant-related complications. We conclude that a metal-backed glenoid component is a good option in total shoulder replacement with no worse results than of those using a cemented all-polyethylene prosthesis.     

Shoulder function and pain level after revision of failed reverse shoulder replacement to hemiarthroplasty

Background:

The reverse total shoulder replacement has become a popular treatment option for cuff tear arthropathy and other shoulder conditions requiring arthroplasty in the setting of a deficient rotator cuff. Despite a revision rate of as much as 10%, to date, there are few reports of reverse replacement conversion to hemiarthroplasty, and none specifically examining shoulder function.

Materials and Methods:

Six patients with a reverse replacement that was dislocated, infected or loose were revised an average of 9.2 months after the reverse replacement. Two of the three patients that were dislocated also had a known deep infection. Patients with known infection were treated with explant of the reverse prosthesis and conversion to a preformed antibiotic spacer hemiarthroplasty. In three cases with gross loosening of the glenosphere without infection, treatment was performed with removal of glenosphere only, bone grafting of glenoid with allograft and conversion of humeral stem to hemiarthroplasty. Patients were evaluated with outcome scores and physical examination an average of 26.5 months after removal of the reverse prosthesis.

Results:

The average range of motion postoperatively was forward elevation 42.5 degrees and external rotation 1.7 degrees. The VAS pain score was 2.42 (range 0–6); simple shoulder test was 3.17 (range 1–5); and ASES score was 52.1 ± 8.5. There were no reoperations to date, and five patients had anterosuperior escape.

Conclusions:

Safe removal of a reverse replacement and conversion to hemicement spacer or hemiarthroplasty can provide pain relief in those patients with a dislocated or infected reverse replacement. However, the shoulder will likely have very poor function and anterosuperior escape postoperatively. Further studies are needed to determine the optimal treatment for the failed reverse shoulder replacement.

Level of Evidence:

Therapeutic Level IV.     

Posterior shoulder instability following anatomic total shoulder arthroplasty: A case report and review of management

We report a case of posterior shoulder instability following anatomic total shoulder arthroplasty (TSA). In addition, we present guidelines to aid in the management of posterior instability after TSA. A 50-year-old male underwent anatomic TSA for glenohumeral osteoarthritis. Postoperatively, the patient developed posterior instability secondary to glenoid retroversion. He did not improve despite conservative treatment. He underwent an arthroscopic posterior bone block procedure, 4-month after his index arthroplasty. At 14-month follow-up, the patient had regained near full motion and strength, and radiographs demonstrated osseous integration with no evidence of component loosening. Posterior instability following TSA is a relatively rare complication and challenging to manage. The posterior, arthroscopic iliac crest bone block grafting procedure represents a treatment option for posterior instability in the setting of a stable glenoid prosthesis following TSA.     

Clinical results of revision shoulder arthroplasty for glenoid component loosening

We retrospectively reviewed 32 patients who underwent glenoid revision surgery after total shoulder arthroplasty to compare the results of revision total shoulder arthroplasty with those of revision hemiarthroplasty and to identify factors associated with poor results after revision shoulder arthroplasty for glenoid component loosening. Results were reviewed at a mean follow-up of 4 years (range, 2-8 years). Glenoid reimplantation resulted in significant pain relief (P < .0001), improvement in American Shoulder and Elbow Surgeons (ASES) score (P < .02), and external rotation (24 degrees to 44 degrees , P < .004). Revision to a hemiarthroplasty also resulted in significant pain relief (P < .01) and improvement in ASES score (P < .05). For the treatment of glenoid loosening without glenohumeral instability, both reimplantation of a glenoid component and revision to a hemiarthroplasty improved function, satisfaction, and level of pain. Reimplantation of a new glenoid component offered greater improvements in pain (P < .008) and external rotation (increase of 20 degrees versus 3 degrees , P < .03) compared with hemiarthroplasty. For patients with preoperative glenohumeral instability, revision surgery did not improve motion, function, or pain significantly. Risk factors associated with a poor outcome after revision arthroplasty included persistent glenohumeral instability, rotator cuff tears, and malunion of the greater tuberosity.