Humeral Components In Shoulder Arthroplasty Research Articles

Tribocorrosion is common but mild in modular humeral components in shoulder arthroplasty: an implant retrieval analysis.

BackgroundWear and corrosion at the junctions of modular implants are increasingly recognized issues in the design of hip and knee arthroplasty prostheses, yet less is known about their significance in shoulder arthroplasty.MethodsA query of paired total shoulder implant specimens (eg, humeral head and stem components from the same patient) was performed using an institutional implant retrieval registry. Implants were examined under a stereomicroscope and evaluated for evidence of fretting and corrosion using the modified Goldberg scoring system. Available electronic medical records of included specimens were reviewed to report relevant clinical characteristics and identify potential associations with the presence of tribocorrosion.ResultsEighty-three paired total shoulder implant specimens, explanted at a single institution between 2013 and 2020, were analyzed. Corrosion was identified in 52% (43/83) of humeral head components and 40% (33/83) of humeral stem components. Fretting was identified in 29% (24/83) of humeral head components and 28% (23/83) of humeral stem components. Of the 56 paired implants for which clinical data were available, the duration of implantation (DOI) was less than 2 years in 29% of paired implants and greater than 5 years in 36% of implants. The presence of corrosion or fretting was not associated with DOI, a male humeral head taper, or periprosthetic infection as the indication for revision.ConclusionMild tribocorrosion was present in more than half of the retrieved humeral implant specimens. However, trunnionosis did not manifest as a clinical cause of revision surgery in our study.

Radiographic alignment of short stem humeral components in shoulder arthroplasty: a multicenter study

IntroductionShort stem humeral stem components represent an area of potential advancement that may decrease the risk of complications associated with traditional length stems, but early data has demonstrated a high rate of malalignment with certain designs. The utilization of a short stem specifically designed to self-align in the proximal portion of the diaphysis has the potential to provide more consistent adequate alignment. MethodsA multicenter retrospective review was performed on 269 shoulders that had undergone an anatomic Total shoulder arthroplasty or a reverse shoulder arthroplasty with implantation of a self-aligning short stem humeral component. Radiographic outcomes included stem alignment and fill-fit ratios. ResultsRadiographs showed adequate stem alignment in 94% of the shoulders. The differences in the superior region canal-fill ratio between the neutral and malaligned group were statistically significant (P < .0003), and the canal-fill rations in the inferior region were also statistically different between the 2 groups (P < .0001). The trend demonstrated higher fill ratios for the neutral stems. ConclusionThe self-aligning short stem analyzed in this study provided a very high rate of adequate stem radiographic alignment. Higher fill ratios were correlated with improved stem alignment. Further studies are needed to understand if improved initial alignment rates correlate with improved patient outcomes or a decreased rate of mechanical failure or other complications. Level of evidenceIV

Short Humeral Stems in Shoulder Arthroplasty.

Since the introduction of shoulder arthroplasty by Neer in 1974, the design of not only the glenoid component but also the humeral component used in shoulder arthroplasty has continually evolved. Changes to the design of the humeral component include a gradually disappearing proximal fin; diversified surface finishes (such as smooth, grit-blasted, and porous coating); a more contoured stem from the originally straight and cylindrical shape; and the use of press-fit uncemented fixation as opposed to cemented fixation. Despite the evolution of the humeral component for shoulder arthroplasty, however, stem-related complications are not uncommon. Examples of stem-related complications include intraoperative humeral fractures, stem loosening, periprosthetic fractures, and stress shielding. These become much more common in revision arthroplasty, where patients are associated with further complications such as surgical difficulty in extracting the humeral component, proximal metaphyseal bone loss due to stress shielding, intraoperative humeral shaft fractures, and incomplete cement removal. Physicians have made many attempts to reduce these complications by shortening the stem of the humeral component. In this review, we will discuss some of the limitations of long-stem humeral components, the feasibility of replacing them with short-stem humeral components, and the clinical outcomes associated with short-stemmed humeral components in shoulder arthroplasty.

Utility and complications of long-stem humeral components in revision shoulder arthroplasty

Currently, there is little information on the benefits and problems associated with long-stem humeral components in shoulder arthroplasty. This study examined the frequency of use, indications, complications, and security of fixation using a long-stem humeral component in revision shoulder arthroplasty. Eighty revision shoulder arthroplasties were monitored clinically for at least 2 years or until repeat revision surgery. The primary indications for use of an intermediate or long stem were proximal bone loss in 40, nonunion in 14, a malpositioned previous stem with bone loss in 10, an acute intraoperative fracture in 7, an acute preoperative periprosthetic fracture in 5, diaphyseal bone loss in 2, and a box-shaped osteotomy to remove a well-fixed stem in 2. Clinical follow-up was an average of 5.9 years, and radiographic follow-up was an average of 4.7 years. Intraoperative complications included fracture removing the previous stem in 5, a cortical perforation in 6, and cement extrusion in 7. Late complications included fracture nonunion in 5, deep infection in 2, and component loosening in 1. One component met criteria to be considered radiographically "at risk" for clinical loosening. Long-stem humeral components are useful to obtain secure fixation in healthy bone in revision shoulder arthroplasty in patients with proximal bone loss, diaphyseal fracture, or a previously malpositioned stem. Complications are frequent, and caution should be taken to avoid intraoperative fractures, distal cortical perforation, or cement extrusion. These components are at low risk for loosening.

Cemented Humeral Stem Fixation: Standard of Care

Cemented humeral stem fixation in shoulder joint arthroplasty has been, and continues to be, the gold standard to ensure satisfactory implant orientation and stability. The most commonly performed type of shoulder arthroplasty is hemiarthroplasty in the face of comminuted fracture. Appropriate stem height and version relative to the glenoid is paramount in obtaining a satisfactory result. This has been proven to be reliably reproducible through cement fixation of the stem with careful reattachment of the tuberosities. Total shoulder arthroplasty in rheumatoid patients with questionable bone stock likewise has relied upon cementation of the humeral component to ensure secure fixation, prevent loosening, and avoid subsidence. In younger patients, it is tempting to want to avoid cement in the proximal humerus; nonetheless, most studies have demonstrated loosening of the humeral component not to be problematic once cement has been used. In addition, newer modular components allow head removal (without stem removal), providing ready access to the glenoid should glenoid revision be needed. In addition, the ability to add antibiotics within the cement mantle in high-risk patients affords an advantage in treating and/or avoiding infection. Survivorship studies have not demonstrated an advantage of cementless versus cement fixation of the humeral component in shoulder arthroplasty.

Cemented Glenohumeral Fixation: Standard of Care—Affirms

Cemented humeral stem fixation in shoulder joint arthroplasty has been, and continues to be the “gold standard” to ensure satisfactory implant orientation and stability. The most commonly performed type of shoulder arthroplasty is hemi-arthroplasty in the face of comminuted fracture. Appropriate stem height and version relative to the glenoid is paramount in obtaining a satisfactory result. This has been proven to be reliably reproducible through cement fixation of the stem with careful reattachment of the tuberosities. Total shoulder arthroplasty in rheumatoid patients with questionable bone stock likewise has relied upon “cementation” of the humeral component to ensure secure fixation, prevent loosening and avoid subsidence. In younger patients it is tempting to want to avoid cement in the proximal humerus, nonetheless most studies have demonstrated loosening of the humeral component not to be problematic once cement has been used. In addition, newer modular componentry allows head removal (without stem removal) providing ready access to the glenoid should glenoid revision be needed. The ability to add antibiotics within the cement mantle in high-risk patients additionally affords an advantage in treating and/or avoiding infection. Survivorship studies have not demonstrated any advantage of cementless versus cement fixation of the humeral component in shoulder arthroplasty. Temporizing techniques such as cup arthroplasty and hybrid techniques such as placing tantalum weave surfaces proximally for enhanced tuberosity fixation may have a role, but do not replace the long-standing efficacy of cement fixation of the humeral component in the vast majority of patients requiring shoulder arthroplasty.

Survivorship of the humeral component in shoulder arthroplasty

Loosening of the humeral component is rarely a cause for revision. This study was conducted to determine long-term survivorship of humeral components and investigate the risk factors associated with humeral component removal or revision. From 1984 to 2004, 1423 patients underwent 1584 primary Neer and Cofield shoulder arthroplasties. The Kaplan-Meier method was used to estimate implant survival. Cox proportional hazards regression was used to assess the effects of age, gender, etiology of the disease, surgery type (hemi vs total), fixation (cemented vs noncemented), and the humeral component design (Neer II, Cofield 1 or 2) with survival free of revision or removal of the humeral component. There were 108 revisions and 17 removals of the humeral component. Estimates of survivorship free of revision or removal of the humeral component for any reason was 94.8% (95% confidence interval [CI], 93.6-96.0) at 5 years, 92.0% (95% CI, 90.4-93.6) at 10 years, 86.7% (95% CI, 84.2-89.4) at 15 years, and 82.8% (95% CI, 78.5-87.5) at 20 years. Younger age, male gender, replacement due to posttraumatic arthritis, an uncemented component, and use of a metal-backed glenoid component increased the likelihood of humeral component failure. The need for revision of the humeral component is commonly related to glenoid or glenoid component issues. Patient and diagnostic factors play a role in implant survival; implant type and method of fixation are less important. Level 4; Case series, treatment study.

Compaction Bone-Grafting in Prosthetic Shoulder Arthroplasty

Compaction bone-grafting has been suggested as a means of improving the stability of the humeral component in shoulder arthroplasty, but the clinical and radiographic results of the procedure have not been reported in the literature, to our knowledge. To address this deficit, we report on a series of shoulder arthroplasties performed with compaction bone-grafting to secure humeral component fixation. These prostheses were implanted in shoulders demonstrating a suboptimal interference fit of the humeral component. Fifty-eight shoulders in fifty-three patients were treated with prosthetic shoulder arthroplasty that included compaction bone-grafting. Clinical assessments were performed at regular intervals with use of visual analog scales for pain, shoulder comfort and function, and overall quality of life, and with use of patient self-assessments including the American Shoulder and Elbow Surgeons Score and the validated Simple Shoulder Test. A detailed radiographic analysis was performed by three raters to determine whether radiolucent lines were present immediately postoperatively and at a later follow-up interval. The humeral tilt angle was determined by measuring the angle between the humeral axis and the component. Subsidence was also evaluated. The mean of the raters' measurements was used in the analysis. The mean duration of follow-up was sixty-nine months (range, twenty-six to 148 months). No loose stems were observed, and no humeral component was revised. At the time of follow-up, there was significant improvement in the Simple Shoulder Test scores and all visual analog scores (p < 0.0001 in each instance). Thirty-four stems had no radiolucent line at the time of follow-up, and the mean maximum thickness of the lucent lines was 0.21 mm in the entire group of fifty-eight shoulders. Most lucent lines occurred near the distal stem tip. The mean tilt of the valgus and varus humeral components was 2.2 degrees and 2.6 degrees , respectively, on the immediate postoperative radiographs. No humeral component shifted from varus to valgus or vice versa. The duration of follow-up was not correlated with the maximum thickness of the humeral component lucency, and the presence or absence of a prosthetic glenoid was also unrelated to the maximum thickness of the lucency. Compaction bone-grafting in shoulder arthroplasty can yield stable and durable fixation of the humeral component, as seen clinically and radiographically, without use of cement. Our findings provide evidence that compaction bone-grafting in shoulder arthroplasty is an option to ensure intermediate-term fixation (at a mean of five years) of humeral components that have a suboptimal fit.

Compaction Bone-Grafting in Prosthetic Shoulder Arthroplasty

Background: Compaction bone-grafting has been suggested as a means of improving the stability of the humeral component in shoulder arthroplasty, but the clinical and radiographic results of the procedure have not been reported in the literature, to our knowledge. To address this deficit, we report on a series of shoulder arthroplasties performed with compaction bone-grafting to secure humeral component fixation. These prostheses were implanted in shoulders demonstrating a suboptimal interference fit of the humeral component. Methods: Fifty-eight shoulders in fifty-three patients were treated with prosthetic shoulder arthroplasty that included compaction bone-grafting. Clinical assessments were performed at regular intervals with use of visual analog scales for pain, shoulder comfort and function, and overall quality of life, and with use of patient self-assessments including the American Shoulder and Elbow Surgeons Score and the validated Simple Shoulder Test. A detailed radiographic analysis was performed by three raters to determine whether radiolucent lines were present immediately postoperatively and at a later follow-up interval. The humeral tilt angle was determined by measuring the angle between the humeral axis and the component. Subsidence was also evaluated. The mean of the raters' measurements was used in the analysis. Results: The mean duration of follow-up was sixty-nine months (range, twenty-six to 148 months). No loose stems were observed, and no humeral component was revised. At the time of follow-up, there was significant improvement in the Simple Shoulder Test scores and all visual analog scores (p < 0.0001 in each instance). Thirty-four stems had no radiolucent line at the time of follow-up, and the mean maximum thickness of the lucent lines was 0.21 mm in the entire group of fifty-eight shoulders. Most lucent lines occurred near the distal stem tip. The mean tilt of the valgus and varus humeral components was 2.2° and 2.6°, respectively, on the immediate postoperative radiographs. No humeral component shifted from varus to valgus or vice versa. The duration of follow-up was not correlated with the maximum thickness of the humeral component lucency, and the presence or absence of a prosthetic glenoid was also unrelated to the maximum thickness of the lucency. Conclusions: Compaction bone-grafting in shoulder arthroplasty can yield stable and durable fixation of the humeral component, as seen clinically and radiographically, without use of cement. Our findings provide evidence that compaction bone-grafting in shoulder arthroplasty is an option to ensure intermediate-term fixation (at a mean of five years) of humeral components that have a suboptimal fit. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Long-term results of uncemented humeral components in shoulder arthroplasty

The purpose of this study was to determine the long-term results of uncemented humeral components in shoulder arthroplasty. We reviewed 37 shoulder arthroplasties with press-fit humeral components with a mean follow-up of 9.2 years (range, 5.8-13.6 years). The mean Constant score was 57 points (range, 16-95 points), and the results in 70% of the patients remained satisfactory. No complications or revisions occurred related to the uncemented humeral component. On radiographic analysis, none of the humeral components showed subsidence. Of the components, 22 (59%) showed radiolucency, 12 (32%) had endosteal erosion, and 5 (14%) had tilted. Of the humeral components, 7 (19%) were judged to be at risk for loosening. The prevalence of an at-risk humeral component was not associated with increasing pain or deteriorating function. This study shows favorable results with the use of uncemented humeral components in shoulder arthroplasty, with a low prevalence of clinical loosening at long-term follow-up.

Radiographic assessment of cemented humeral components in shoulder arthroplasty

Forty-three shoulder arthroplasties performed with the use of cemented Neer II humeral components and followed radiographically for a mean of 6.6 years (range, 2-20 years) were analyzed. A humeral component was considered radiographically “at risk” for clinical loosening when a radiolucent line 2 mm or greater in width was present in 3 or more zones or tilt or subsidence was identified on sequential radiographs by 2 or 3 of the 3 independent observers. None of the components was considered to have tilted or subsided. Radiolucent lines of any size were present in 16 shoulders and were wider than 2 mm in 9 shoulders. They were limited to 1 zone in 8 shoulders and to 2 zones in 7 shoulders. Only 1 component (2%) with a 2-mm radiolucent line in 3 zones was judged to be “at risk.” The incidence, extent, and thickness of humeral radiolucent lines were significantly higher in total arthroplasties than in hemiarthroplasties (P <.05). Clinically important changes around cemented Neer II humeral components are uncommon. Humeral radiolucent lines develop more frequently in the presence of a glenoid component. Data from this study can be used as one benchmark to compare with alternate methods of humeral component fixation. (J Shoulder Elbow Surg 2001;10:526-31.)

A Conservative Broaching and Impaction Grafting Technique for Humeral Component Placement and Fixation in Shoulder Arthroplasty: The Procrustean Method

Techniques for placement and fixation of the humeral component in shoulder arthroplasty have evolved over the past 40 years. This article reviews the comparative advantages and disadvantages of three commonly used methods for humeral prosthetic fixation (porous in-growth, classic press-fit, and cementing) and compares them with our presented technique of conservative broaching and impaction grafting. In this presented method, morcellized cancellous bone from the resected humeral head is sequentially impacted into the metaphyseal and proximal diaphyseal regions of the proximal humerus. This graft serves to 1) fill voids between implant and bone to improve fixation, 2) preserve bone stock, 3) allow for optimization of implant position, 4) minimize the risk of fracture compared with the conventional press-fitting technique, and 5) minimize the need for complex prosthesis modularity.