Glenoid Prosthesis Research Articles

Paper #3 - Comparison of cemented polyethylene peg and hybrid cage glenoids in total shoulder arthroplasty

Introduction: Aseptic glenoid loosening remains a long-term complication of total shoulder arthroplasty (TSA). To improve long-term fixation and decrease the risk of aseptic loosening, glenoid components with hybrid fixation, consisting of a large metal ingrowth central peg and cemented peripheral pegs, have been developed. The purpose of this prospective study is to determine the clinical and radiographic outcomes of a hybrid cage glenoid component compared to an age and gender matched polyethylene (PE) peg glenoid component with a minimum tow year follow-up. Methods: Ninety-two patients with a mean age of 63 years were treated with a TSA for osteoarthritis by 7 surgeons using either a cemented pegged glenoid or a hybrid fixation cage glenoid. Forty-six patients who received a cage glenoid (19 female and 27 males) were matched for sex and age with 46 patients who received a peg glenoid, and all had a minimum 2 year follow-up. The patients were scored preoperatively and at latest follow-up using the SST, UCLA, ASES, Constant, and SPADI metrics; active abduction, forward flexion, and active and passive external rotation were also measured. The average follow-up for all patients was 26 months (cage 25 months; peg 26 months). A Student's two-tailed, unpaired t-test was used to identify differences in preoperative, postoperative, and pre-to-post-operative improvements in results, where P < .05 denoted a significant difference. IRB approval was obtained at each institution. Results: All patients demonstrated significant improvements in pain and function following TSA with a cage or peg glenoid (P < .0001). For the cage prosthesis, ASES scores improved from 37 to 89, Constant scores from 39 to 76 (P < .0001). Significant improvements were also seen in the SST, UCLA and SPADI scores (P < .001). For the peg glenoid, ASES scores improved from 35 to 84, Constant scores from 39 to 69 (P < .0001), and significant improvements were also seen in the SST, UCLA and SPADI scores (P < .0001). Active forward flexion for a cage glenoid improved from 104° to 149° and active external rotation from 22° to 49°. Active forward flexion for a peg prosthesis improved from 92° to 135° and active external rotation from 16° to 47° (all P < .0001). Cemented peg glenoids were noted to have significantly lower preoperative abduction measurements; however, no significant differences were observed in any postoperative clinical metric or motion measurement except for the SPADI score (P = .0497) and active forward flexion (P = .0427). Cage prostheses were associated with significantly less blood loss than a peg glenoid (mean blood loss, 242 cc vs 337 cc; P = .022). Radiolucent lines were noted in 14% of cage glenoid patients and 28% of peg patients. There were no cases of radiographic or clinical loosening, clinical failures or revisions in either cohort. There were 3 complications in the cage glenoid group and 4 complications in the peg patients. Discussion: Similar clinical outcomes were found at a minimum two years follow-up comparing a standard cemented peg glenoid with a hybrid cage glenoid prosthesis. The 50% reduction in radiolucent lines for the cage relative to the cemented peg glenoid is significant. This is a proof of concept study demonstrating statistically significant clinical improvements and a significant decrease in the incidence of radiolucent lines following implantation of a hybrid cage glenoid component. Additional and longer-term follow-up is needed to confirm these early outcomes.

Retroversion angle of the glenoid cavity in South Indian population

Background and aims: Glenoid version angle is tilt of glenoid cavity in relation to the plane of scapula, it is recorded as anteversion if glenoid is open anteriorly, and retroversion if it faces posteriorly. The tilting angle of the glenoid cavity has a role in shoulder stability. In end-stage glenohumeral arthritis, wear is usually greater in the posterior half of the glenoid articular surface effectively increasing glenoid retroversion (RV). Aligning the glenoid prosthesis to the face of retroverted glenoid increases the risk for glenoid implant loosening. As Indian literature for retroversion is limited, this study was undertaken. The aim was to estimate and compare the version angle of the glenoid cavity of right (Rt) and left (Lt) dry scapulae. Material and Methods: Superior view of 200 dry scapulae (100 right and 100 left) were photographed using a digital camera. The images were transferred to Microsoft power pointR 2007 software and using Image J software glenoid version angle were measured. Results were analysed using SPSS 16. Independent sample t test was used to compare right and left sides. Results: Ninety eight of hundred Lt glenoid were retroverted with a mean angle -5.02 ± 2.07°, two were anteverted with mean value+1.65°. All the 100 Rt glenoid were retroverted with mean of -6.90 ± 3.48°. There is significant difference in the angle of glenoid version of left and right glenoid cavity with a p value

Retroversion angle of the glenoid cavity in South Indian population

Abstract Background and aims: Glenoid version angle is tilt of glenoid cavity in relation to the plane of scapula, it is recorded as anteversion if glenoid is open anteriorly, and retroversion if it faces posteriorly. The tilting angle of the glenoid cavity bas a role in shoulder stability. In end-stage glenohumeral arthritis, wear is usually greater in the posterior half of the glenoid articular surface effectively increasing glenoid retroversion (RV). Aligning the glenoid prosthesis to the face of retroverted glenoid increases the risk for glenoid implant loosening. As Indian literature for retroversion is limited, this study was undertaken. The aim was to estimate and compare the version angle of the glenoid cavity of right (Rt) and left (Lt) dry scapulae. Materials and Methods: Superior view of 200 dry scapulae (100 right and 100 left) were photographed using a digital camera. The images were transferred to Microsoft power point R 2007 software and using Image J software glenoid version angle were measured. Results were analysed using SPSS 16. Independent sample t test was used to compare right and left sides. Results: Ninety eight of hundred Lt glenoid were retroverted with a mean angle -5.02 ± 2.07°, two were anteverted with mean value+1.65°. All the I 00 Rt glenoid were retroverted with mean of -6.90 ± 3.48°. There is significant difference in the angle of glenoid version of left and right glenoid cavity with p value &lt;0.01. Conclusion : Proper implant positioning is key issue in shoulder arthroplasty for efficient postoperative function and long-term survival of the implant. Hence preoperative assessment of glenoid version is essential.

The association of incomplete glenoid component seating and periprosthetic glenoid radiolucencies after total shoulder arthroplasty

Radiolucent lines surrounding prosthetic glenoid components are commonly seen after unconstrained total shoulder arthroplasty and can be a harbinger of subsequent glenoid component failure. Whether less than 100% glenoid seating is associated with the development of radiolucent lines around glenoid prostheses is unknown. This study investigated the association between incomplete glenoid component seating and periprosthetic glenoid radiolucencies. Thirty-six unconstrained total shoulder arthroplasties were performed in 29 patients for primary glenohumeral osteoarthritis with a minimum 2-year follow-up. All were implanted with a partially cemented all-polyethylene glenoid prosthesis. Patients were evaluated with standardized plain films preoperatively and postoperatively and with thin-cut computed tomography (CT) scans at the latest follow-up. The Lazarus and Yian classifications were used to assess radiolucency and seating on radiographs and CT scans. Ratings were calculated for intraobserver and interobserver reliability and given κ, the Kendall coefficient, and interclass correlation coefficient values. At a mean of 43 months (range 24-26 months) after surgery, neither Lazarus plain film radiolucency scores (P = .78) nor Yian CT radiolucency scores (P = .68) were associated with Lazarus plain film seating scores. Neither Lazarus plain film radiolucency scores (P = .25) nor Yian CT radiolucency scores (P = .91) were associated with modified Lazarus CT scan seating scores. CT allowed for better intraobserver and interobserver reliability in all categories. Radiolucencies around a partially cemented glenoid component were not associated with the degree of component seating. Complete seating of the glenoid component is not necessary to achieve radiographic implant stability at a mean follow-up of 43 months.

The glenoid component in anatomic shoulder arthroplasty.

Ideal management of the glenoid in anatomic shoulder arthroplasty remains controversial. Glenoid component loosening remains a common source of clinical concern and, in young, active patients, implantation of a glenoid prosthesis is often avoided. Efforts to decrease glenoid loosening have resulted in changes to prosthetic design and implantation techniques. Currently, a wide variety of glenoid component options are available, including metal-backed or all-polyethylene, bone ingrowth or ongrowth, inset, and augmented designs. Additionally, several alternatives are available for the young, active patient, including hemiarthroplasty, nonprosthetic resurfacing, and tissue interposition. Many recent clinical and biomechanical studies have examined these implant options. A thorough knowledge of glenoid anatomy, pathology, implant options, indications, and principles of implantation is necessary to optimize the outcome following anatomic shoulder arthroplasty.

Effects of osteoarthritis on load transfer after cemented total shoulder arthroplasty

Total shoulder arthroplasty is commonly performed to treat glenohumeral osteoarthritis (OA); however, little is understood of the mechanics of the reconstructed OA shoulder. We sought to establish the effects of OA-induced changes in bone density and retroversion angle on load transfer and stress distribution in the bone-implant system of the scapula. We developed finite element models of reconstructed healthy and OA scapulas with a virtually implanted glenoid prosthesis design. For the OA scapula, models with uncorrected and corrected retroversion were created. Loads were applied at the center or posteriorly on the glenoid surface. Our results suggest that with reconstruction of the corrected glenoid with a contemporary implant, cement stresses increase and the load transfer pattern changes with eccentric loads. The load transfer and local stresses in the bone-implant system in the retroverted glenoid are less sensitive to changes in loading location. Furthermore, the load transfer in the OA glenoid is less sensitive to the effect of peg proximity to the cortical shell than in the healthy glenoid. We provided evidence of how load sharing is altered among healthy, corrected OA, and retroverted OA glenoids. We demonstrated that correction of retroversion in OA glenoids may actually increase the risk for stress shielding and cement failure compared with retroverted glenoids, and OA patients can accommodate shorter pegs because of the higher glenoid bone stiffness in the OA glenoid.

Humeral Head Replacement Combined with Meniscal Allograft Interposition versus Non-Prosthetic Glenoid Arthroplasty: Preliminary Data from a Prospective Randomized Clinical Trial

Treatment of glenohumeral arthritis in young patients after failure of nonoperative measures presents a unique clinical challenge. Concerns about wear and loosening of polyethylene glenoid prostheses have led many surgeons to consider hemiarthroplasty in this patient group. Both non-prosthetic glenoid arthroplasty (NPGA; “ream and run”) and meniscal allograft interposition (MAI) have shown promise for improving function and comfort in single-surgeon case series, but no comparative study has yet been performed to compare the relative efficacy of each method. The purpose of this work is to present interim results of a prospective, randomized clinical trial with minimum two-year follow-up of all reported patients.

Structure modeling of the glenoid: Relevance to shoulder arthroplasty.

We applied shape modeling and principal component analysis (PCA) to discover glenoid bone structural relationships relevant to improving glenoid prosthesis features, fixation, and instrumentation. Knowledge of external bone morphology guides prosthesis shape and positioning, while internal bone morphology and bone density influence fixation. CT-based modeling defined nonarthritic glenoid subchondral bone surface and internal structure. First and second principal shape components were related to size and density. Reproducible structural parameters and glenoid feature relationships were discovered. Subchondral bone surface was approximated by a circle inferiorly and a triangle superiorly with the circle's center at a reproducible point along a superior-inferior line. Glenoid vault's maximum depth was at the circle's center, and the highest bone density was in posterior glenoid. Glenoid subchondral bone surface version varied from superior to inferior, but not by sex or side. Male subchondral bone surfaces were larger and more retroverted. Even if subchondral bone surfaces are deformed by arthritis, glenoid morphology can be identified by extra-articular landmarks, permitting location of the glenoid center and scapular orientation (glenoid version). Knowledge obtained from this study directs design of novel prosthesis features and instrumentation for use without pre-op CT or computer aided surgery.

Load transfer after cemented total shoulder arthroplasty

Glenoid loosening is the primary reason for failure after a total shoulder arthroplasty (TSA), but the failure mechanism is not yet known. This study determined how the load transfer and stress distribution are affected by the introduction of a glenoid implant. We developed a finite-element model of a scapula with and without a virtually implanted modern glenoid prosthesis design. Two load magnitudes were considered: normal and high. Loading locations were simulated at the center and at 4 eccentric positions on the glenoid. A metal-backed implant was also simulated to understand the effect of fixation stiffness. In the intact glenoid, for both center and eccentric loading, the majority of stress was distributed in the cancellous bone, whereas after a reconstruction, stresses in that region were lower. Metal-backed implants further decreased the joint load carried by the bone. Stresses in the cement layer increased during eccentric and high-magnitude loading. This study provided a basic understanding of the load-sharing phenomenon after a TSA that could explain glenoid loosening failure. Our results suggest that with reconstruction of the glenoid with a contemporary implant, the load transfer pattern is significantly altered, with eccentric and high-magnitude loads increasing stresses in the cement indicating potential for failure. The use of a metal-backed implant reduces the load carried by the bone, which may be detrimental to long-term TSA survival.

Managing glenoid bone loss virtual surgery—A software solution

Inaccurate placement of glenoid prosthesis in shoulder arthroplasty can lead to early loosening, instability, and failure. To address difficult glenoid morphology, patient-specific instrumentation and navigation techniques have been developed. Advanced imaging data has demonstrated utility in preoperative decision making. Cadaveric studies have subsequently shown that the application of advancing imaging and navigation can lead towards increased accuracy with prosthesis placement. Clinical trials have also shown increased accuracy with navigation and advanced imaging, but data demonstrating improved long-term outcomes and decreased complication rates is not yet available. This technology continues to evolve as a method to address glenoid bone loss and abnormal morphology.

Metal-Backed Glenoid Prostheses

Despite the theoretical advantages of uncemented glenoid prostheses, clinical experience with uncemented metal-backed glenoids (MBG) has been disappointing to date. MBG design features have varied widely and, unlike the systematic ‘generational’ refinement of cemented glenoid prostheses, MBG design has been haphazard and unsystematic. The advent of reverse prostheses has rekindled interest in MBGs that allow ‘exchange’ from ‘anatomic’ to ‘reverse’ without baseplate removal. Recent designs, based on earlier prostheses, have proven excellent medium-term results, and there are now some specific indications for the use of MBGs. Further refinements are expected.

Magnetic resonance scanning vs axillary radiography in the assessment of glenoid version for osteoarthritis

Osteoarthritic shoulders are mainly associated with glenoid retroversion. Total shoulder arthroplasty with the glenoid component implanted in retroversion predisposes to loosening of the glenoid prosthesis. Correction of glenoid retroversion through anterior eccentric reaming, before glenoid component implantation, is performed to restore normal joint biomechanics. Accurate preoperative assessment is required to ascertain the degree of retroversion and calculate the degree of reaming. We assessed the utility of magnetic resonance imaging (MRI) for the assessment of glenoid version in glenohumeral osteoarthritis compared with standard plain axillary radiography (AXR). Two independent observers reviewed both types of imaging in 48 primary osteoarthritic shoulders on 2 separate occasions. The mean glenoid version measured was -14.3° on MRI and -21.6° on AXR (mean difference, -7.36°; P < .001). Intraobserver and interobserver reliability coefficients were 0.96 and 0.9, respectively, for MRI and 0.8 and 0.71, respectively, for AXR. Glenoid retroversion was greater in 73% of AXR. We demonstrated that MRI is more reproducible in the assessment of glenoid version in osteoarthritis and provides excellent intraobserver and interobserver reliability. MRI is useful for preoperative osseous imaging for total shoulder arthroplasty because it offers a more precise method of determining glenoid version compared with x-ray imaging in addition to the standard assessment of rotator cuff integrity.

How to deal with glenoid type B2 or C? How to prevent mistakes in implantation of glenoid component?

Although TSA has been shown to significantly yield better outcomes than hemiarthroplasty, glenoid prosthesis loosening remains the most common complication. Inadequate primary fixation enables the glenoid component to move. In primary glenohumeral osteoarthritis (GHOA), glenoid involvement and proper morphology vary considerably. Postero-inferior glenoid hypoplasia could be associated with some degree of osteoarthritis. According to Walch, 24 % of glenoids in GHOA are type B2 or C (excessive posterior retroversion), which increases the challenge for the glenoid component fixation. A total of 30 cases of TSR with glenoid type B2 (20 cases) and type C (10 cases) were reviewed. Mean follow-up was 11.2 months. A metal-backed (MB) glenoid component was implanted, with a posterior bone graft reconstruction. Pre- and post-operative clinical evaluation was done using the Constant-Murley score and the SST from Matsen. There is no glenoid loosening, no joint narrowing and no radiolucent line. There was no bone graft osteolysis. With 4 patients revised (4 conversions from TSR to RSR for 3 instabilities and 1 secondary rotator cuff tear), on the overall 30 patients cohort, Constant score pain increased from 1.6 to 13.4, forward flexion from 92° to 146° and Constant score from 27 (36 %) to 70 (95 %). The statistical difference between pre- and post-operative values is greatly significant. Although MB prostheses have been noted to have a higher rate of loosening than full-cemented PE, this is not our experience, even in case of glenoid type B2 or C, where the technical challenge is demanding and most of the time a posterior bone graft is necessary.

Functional and clinical outcome of total shoulder arthroplasty with oversized glenoid

The Epoca-Reconstruction-(Reco)®-Glenoid has been developed to treat patients with cuff-tear-arthropathy. The glenoid component of this system has a hemispheric shape that canopies the humeral head. This design is believed to provide a stable fulcrum and restore normal deltoid function. The purpose of this study was to analyse strengths and disadvantages of the Epoca-Reco®-Glenoid in cuff-tear-arthropathy patients. Changes in functional outcome using Constant-Murley-Scoring(CMS), CMS sub-scoring parameters and radiological outcome were analysed. For this purpose, a classification for radiologic lucency was proposed. Diverging results, influencing factors and alternative treatment options have been discussed to analyse weaknesses and enhance future development of this arthroplastic model. 23 patients aged 68 ± 8.4 years with irreparable cuff-tear-arthropathy refractory to physiotherapeutic treatment were treated with Reco-Glenoid Total-Shoulder-Arthroplasty (TSA). Pre-operative standardized evaluations included history, physical examination, radiographs, computer tomography and clinical scorings. The post-operative controls included physical examination with CMS, video documentation and radiological evaluation. After a median follow-up time of 38 ± 18 months, the CMS had been significantly improved (p < 0.001) from (17.4 ± 5.8) to (43.2 ± 19.2) points. Significant improvement in pain, activities of daily life, range of motion (p < 0.001) and power (p = 0.006) was achieved. Significantly, inferior results in functional outcome and higher lucency rates were observed in female patients and in patients treated with small glenoid components. The follow-up rate was 100 %. The semi-constraint reconstruction glenoid prosthesis model in cuff-tear-arthropathy patients significantly improves shoulder function, however, it yields controversial results, with satisfactory results in male and poor results in female patients. Revision rate of the female cohort and loosening of the glenoid component in this short-term follow-up is of concern. Further investigations taking BMD, osteopenic conditions and influence of surface area in smaller individuals into consideration are recommended, to determine whether this is the underlying cause of the inferior results in females.

An experimental glenoid rim strain analysis for an improved reverse anatomy shoulder implant fixation

Loosening of glenoid components in TSA is a main cause of failure. In reverse anatomy TSA designs used for unstable joints, fixation is particularly demanding. Strains developed around the glenoid rim of biomechanical sawbone scapulae implanted with (a) the original fixed-fulcrum Bayley-Walker glenoid prosthesis in current clinical use, and (b) a revised version with conical cross-section, were compared. The conical shape of the revised design was hypothesized to produce greater strains in the glenoid rim than the original tapered screw design. The 2D strain field at three accessible locations around the rim of each scapula was measured with three-element rosette strain gauges for two types of simulated cancellous bone fill under applied physiologically relevant loads. The average strain energy densities around the rim for the conical design were greater than for the original design by a factor of 1.55-2.25 for all loading conditions. Results indicate that a significantly greater proportion of load was directed toward cortical bone in the conical design, thus promoting cortical bone loading.

A 2-dimensional glenoid vault method for measuring glenoid version on computed tomography

Accurate placement of the glenoid prosthesis in shoulder arthroplasty is critical; precise glenoid prosthesis alignment being a key element to avoid poor fixation and early loosening. The current recognized 2-dimensional (2-D) method for measuring glenoid version may be irrelevant to the above, as it does not take into account the complex and variable relationship of the scapular body in relation to the glenoid. On the contrary, a 3-dimensional (3-D) method, which focuses solely on the glenoid, is superior but not readily accessible. We have, therefore, developed a new 2-D method based solely on the glenoid vault which is readily accessible. To determine normal version using our method, computer tomography (CT) scans of 107 normal shoulders were assessed as the control group. We then assessed 63 arthritic shoulders to establish any significant difference. Inter- and intraobserver reliability were assessed using 4 observers who independently reviewed 50 blinded CT images 3 weeks apart. For comparison, the currently recognized method, as described by Friedman et al, was also utilized in this study. Using our new method, the mean glenoid version in the control group was 19 ± 3° of retroversion; and in the arthritic group, 25 ± 6° of retroversion. Intra- and interobserver reliability were very high. Our new 2-D glenoid vault method is relevant, as it focuses solely on the glenoid vault, is precise with a low standard deviation, and is reliably reproducible as shown by the intra- and interobserver reliability data, all while remaining readily accessible.

Mechanical characteristics of a novel posterior-step prosthesis for biconcave glenoid defects

Posterior glenoid defects increase the risk of glenoid component loosening after total shoulder arthroplasty (TSA). The goal of this work was to evaluate the mechanical performance of a novel posterior-step glenoid prosthesis, designed to compensate for biconcave (type B2) glenoid defects. Two prototypes ("Poly-step" and "Ti-step") were constructed by attaching polyethylene or titanium step-blocks onto standard (STD) glenoid prostheses. We hypothesized that the mechanical performance of the experimental prostheses in the presence of a B2 defect would be similar to that of an STD prosthesis in the absence of a defect. Fifteen normal shoulder specimens were consistently loaded under simulated muscle activity while peri-glenoid bone strains were measured. In 5 specimens, arthroplasty was performed with an STD glenoid prosthesis. In the remaining 10 specimens, a 20° B2 glenoid defect was created before arthroplasty was performed with the Poly-step or Ti-step prosthesis. Load-induced peri-glenoid strains after TSA with either the STD or Poly-step prosthesis did not show statistical differences as compared with the native joints (P > .05). A posterior defect decreased superior glenoid strain as compared with the intact specimens (P < .05). The change in strains after Poly-step prosthesis implantation in the presence of a biconcave glenoid defect was not different than the change induced by STD prosthesis implantation in the absence of a defect. In contrast, strains after Ti-step prosthesis implantation were statistically different from those induced by the STD and Poly-step prostheses (P< .05). The Poly-step prosthesis may be a viable option for treating posterior glenoid defects.

Post-treatment glenoid classification system for total shoulder arthroplasty

Over the past 10 years, numerous advancements in glenoid preparation and resurfacing have occurred. Current glenoid classification systems are either focused solely on the patient's preoperative glenoid bone configuration or on the available glenoid bone stock in revision arthroplasty cases. While these systems provide value in preoperative planning, they fail to properly classify the surgical reconstruction completed. A literature review of common bone preparation methods and sources of glenoid prosthetic failure was performed. Based upon this review, a classification system for grading the status of the glenoid after prosthetic implantation was developed. A 6 category, post-treatment, glenoid classification system is proposed: type 0: no reaming; type I: glenoid reaming into but not through the subchondral bone; type II: glenoid reaming which perforates through <50% of the subchondral bone surface area; type III: glenoid reaming which perforates through >50% of the subchondral bone surface area; type IV: use of structural bone graft; and type V: use of a posterior augmented glenoid prosthesis. Types I-III are further subdivided into subtype A which have 100% bone support of the prosthesis, and subtype B which have a region of unsupported prosthesis. The classification system proposed addresses the surgical management of the glenoid during prosthetic replacement. This unique approach to classifying the glenoid following surgical intervention will allow direct follow-up comparison of similarly treated glenoid replacements. Future multicenter studies, possibly through joint registry databases, could then determine the long-term efficacy of the various glenoid preparation methods.

Bony Increased-Offset Reverse Shoulder Arthroplasty (BIO-RSA) for Cuff Tear Arthropathy

Given the disappointing results of hemiarthoplasty and the unacceptably high failure rates of total shoulder protheses, reverse shoulder arthroplasty (RSA) has become an attractive treatment option for patients with painful cuff tear arthropathy. Grammont's original medialized design represented a major advance in the restoration of shoulder function for these patients. Scapular notching, prosthetic instability, limited shoulder rotation, and loss of shoulder contour are all problems resulting from the medialization of the center of rotation, stimulating others, in turn, to develop lateralized RSA designs. Rather than changing the geometry of the glenoid prosthesis, our approach to achieving lateralization has been to increase the bony offset of the glenoid. In this article, we present the surgical technique of bony increase-offset reverse shoulder arthroplasty (BIO-RSA). By using a modified base-plate with a lengthened central peg, we place a cancellous bone graft harvested from the humeral head beneath the baseplate of the RSA, effectively creating a long-necked scapula. At a minimum of 2 years after surgery, in a prospective cohort of 42 patients receiving BIO-RSA, there were no cases of glenoid loosening or prosthetic instability. Computed tomography and plain radiographic review demonstrated healing of all glenoid bone grafts. Scapular notches were observed in only 9 cases. Significant improvements were observed when disease-specific outcome measures were used and in all planes of shoulder mobility. BIO-RSA appears as a biological solution to minimize inferior scapular notching and to maximize shoulder stability and mobility without increasing the risk of glenoid component failure. Healing of the humeral bone graft on the native glenoid is consistently observed, allowing the creation of a scapula with a long neck. In contrast to metallic increased-offset, BIO-RSA offers the advantage of maintaining the center of rotation of the joint at the prosthesis-glenoid interface and therefore minimizing torque on the glenoid component.

Long-term results and patient satisfaction after shoulder resurfacing

Shoulder resurfacing has regained popularity in recent years. This report presents the long-term (>20 years) results of this procedure with regard to patient satisfaction and implant survival. We followed up 61 patients who underwent shoulder resurfacing procedures (74 shoulders) for a minimum of 20 years or until death (7 additional patients were lost to follow-up). The mean patient age at the time of surgery was 58 years. There were 41 total resurfacing procedures and 33 hemi-resurfacing procedures. The humeral component consisted of a cup with a short central peg that was placed either with or without cement. The glenoid was resurfaced with a cemented polyethylene or polyurethane component. Patient satisfaction was 95%, and the survivorship of the humeral prostheses was 96%. There were no periprosthetic fractures, dislocations, or infections. Two humeral components were revised to stemmed prostheses (one for loosening and one for unexplained pain), and one was revised from a cementless to a cemented resurfacing prosthesis. Twelve cemented polyethylene glenoid prostheses had radiolucencies, but only three produced symptoms requiring revision surgery; three polyurethane glenoid prostheses showed severe wear radiographically, but none was loose or required revision surgery. There were 7 revision procedures, 6 with good results. Shoulder resurfacing is a successful procedure for the majority of patients, with high rates of patient satisfaction, long-term survivorship of the humeral prosthesis, and few complications.