Clinical and radiologic outcomes of the second-generation Trabecular Metal™ glenoid for total shoulder replacements after 2-6 years follow-up

A multicenter, randomized controlled trial comparing a second-generation uncemented trabecular metal-backed vs. cemented polyethylene glenoid component in total shoulder arthroplasty: 5-year results

BACKGROUND

Previously, we reported early (2-year) findings from a randomized controlled trial comparing a second-generation uncemented trabecular metal-backed (TM) glenoid vs. cemented polyethylene glenoid (POLY) in patients undergoing a total shoulder arthroplasty. The purpose of the current study is to report disease-specific quality of life, clinical, patient-reported, and radiographic outcomes at midterm (5-year) from this trial.

METHODS

Five surgeons from 3 centers participated. Patients 18-79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Randomization to an uncemented TM or cemented POLY glenoid was performed intra-operatively after adequate bone stock was confirmed. Study intervals were baseline, 2- and 5-year postoperative. The primary outcome was the Western Ontario Osteoarthritis Shoulder (WOOS) quality of life score. Secondary outcomes included the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, EuroQol-5 Dimensions, and 12-Item Short Form Health Survey scores and clinical and radiographic examinations. Radiographic images were reviewed for metal debris according to Endrizzi. Mixed effects repeated measures analysis of variance for within- and between-group comparisons were performed.

RESULTS

Of the 104 patients who consented, 93 were randomized (46 TM; 47 POLY). There were no differences between groups at baseline (TM: mean age 66.5 years [standard deviation (SD) 6.4], 24 male and 22 female; and POLY: mean age 68.4 years [SD 5.5], 23 male / 24 female). Mean (SD) WOOS scores at baseline and 2 and 5 years were as follows: TM, 32 (21), 92 (13), and 93 (11); POLY, 27 (15), 93 (11), and 93 (10), respectively. No statistical or clinically relevant differences were noted with patient-reported outcomes between groups. Metal debris was observed in 11 (23.9%) patients, but outcomes were not negatively impacted, and debris severity was minor (grades 1 and 2). Complication rates were similar between groups (TM: 7 of 46 [15.2%], and POLY: 8 of 47 [17.0%]; P = .813). No aseptic glenoid failures were reported, but 1 patient in the TM group required revision because of infection.

CONCLUSIONS

Our short-term (2-year) findings were maintained with longer follow-up. At 5 years postoperation, there were no statistically or clinically significant differences between an uncemented second-generation TM glenoid and a cemented polyethylene glenoid with respect to disease-specific quality of life or patient-reported outcomes. No glenoid implant failures were reported, and complication rates were similar between groups. Only one complication was glenoid related (1 infection in the TM group). Metal debris was observed in 23.9% of patients with a TM glenoid but did not negatively influence implant survival, patient-reported outcomes, or shoulder function.

Common Factors in Shoulder and Hip Arthroplasty Implant Failures: A Historical Review

In this era of subspecialty care in orthopedics, iterations of implant design can occur in a silo which then precludes gaining knowledge from failures of implant design that may have occurred in different subspecialties. This literature review describes the history of failures in hip and shoulder arthroplasties with the purpose of identifying similar factors that led to previous implant failures. A review of the literature was performed by two reviewers assessing articles that described failed hip and shoulder arthroplasty systems over time. We identified and analyzed 53 implant failures-23 in hip arthroplasty and 30 in shoulder arthroplasty. These failures were categorized as material, mechanical, and technical. In hip arthroplasty, 48% were material, 39% mechanical, and 13% technical failures. In shoulder arthroplasty, the distribution was 10% material, 70% mechanical, and 20% technical failures. The distribution of these failures highlights similar and sometimes repeated failure mechanisms between subspecialties. This accentuates the importance of a collaborative approach to improve future arthroplasty designs.

Outcomes and survivorship of anatomic total shoulder arthroplasty: current concepts

Total shoulder arthroplasty (TSA) has been the gold standard of care for end-stage glenohumeral arthritis. Outcomes are varied and have been affected by both patient and implant characteristics. Patient factors, such as age, preoperative diagnosis, and preoperative glenoid morphology, can affect the outcomes after TSA. Similarly, the different glenoid and humeral component designs significantly affect the survivorship of TSA. Significant evolution has occurred in the design of the glenoid component with the aim of decreasing the glenoid-sided causes of failure in TSA. On the other hand, focus on the humeral component has been increasing as well, with a trend towards using shorter humeral stems. This article aims to look at the outcomes of TSA as affected by the various patient characteristics and design options for the glenoid and the humeral components. This review also aims to compare survivorship data from global literature and the Australian joint replacement registry and to provide insights into the implant combination that may provide the best patient outcome.

Can convertible metal-backed glenoid components replace cemented polyethylene glenoid components in anatomical total shoulder arthroplasty?

BACKGROUND

Anatomical total shoulder arthroplasty (aTSA) has been used to manage degenerative diseases such as primary osteoarthritis. An increase in the use of this procedure has led to several developments in humeral and glenoid components to improve patient outcomes. This study aimed to compare clinical and radiological outcomes of the newly-introduced convertible metal-backed glenoid components with cemented polyethylene glenoid components in aTSA, and to determine whether the new component would be comparable to a conventional one for reducing the burden of future revision or conversion surgeries.

METHODS

Medical records of fifty patients who underwent aTSA with at least two years of follow-up were retrospectively reviewed. Eighteen patients received convertible metal-backed glenoid components with vitamin E1-coated liner (MB group), while thirty-two patients received conventional cemented polyethylene glenoid components (PE group). Pre- and postoperative clinical and radiological outcomes (acromion-greater tuberosity angle [AGA] and humeral lateral offset [LO]) at final follow-up were assessed. Radiolucent lines (RLLs) and loosening around the humeral and glenoid components were also evaluated.

RESULTS

Clinical outcomes improved after surgery in both groups (all p < 0.001). The arc of rotation measured by AGA improved postoperatively in both groups (all p < 0.001), and AGA and LO were not different according to the type of glenoid components (all p > 0.05). Overall complication rates including RLLs of PE and MB groups were 43.8% (14/32) and 16.7% (3/18), respectively (p = 0.031). Although the PE group had more RLLs than did the MB group (p < 0.05), related symptoms and/or glenoid implant loosening were not observed in both groups. Subscapularis failure occurred in two patients in the PE group and in one in the MB group.

CONCLUSION

The convertible metal-backed glenoid implant with vitamin E1-coated liner may be a good alternative for considering the potential for an easier conversion to reverse total shoulder arthroplasty.

Evaluation of clinical and radiographic outcomes after total shoulder arthroplasty with inset Trabecular Metal-backed glenoid

BACKGROUND

Trabecular Metal (TM)-backed glenoid implants were introduced for their theoretical ability to increase osseointegration while minimizing wear and the risk of loosening in total shoulder arthroplasty (TSA). Initial follow-up studies of TM-backed glenoids demonstrated high rates of metallic debris formation around the implant site, raising concerns about longevity. More recent data suggest that metallic debris formation may be less prevalent than previously reported and that the implants may have positive long-term outcomes regardless of debris. The goal of our study was to assess the clinical and radiographic outcomes at mid-term follow-up of TSA using a TM-backed glenoid implant placed with full backside support using an inset technique. We hypothesized that our clinical and radiographic outcomes would be good using this technique.

METHODS

We retrospectively reviewed the charts of 39 patients who underwent 41 TSA procedures with a Zimmer Biomet TM-backed glenoid component performed by a single surgeon between January 2010 and March 2016. After exclusions for death unrelated to surgery and loss to follow-up, 35 patients (37 shoulders) with minimum 2-year clinical follow-up were included in the study. The glenoids were all placed in an inset fashion with full backside support. Clinical, patient-reported, and radiographic outcomes were analyzed.

RESULTS

The average follow-up period was 7.2 years (range, 2-11 years). At final follow-up, average shoulder elevation was 153° ± 22° and average external rotation was 53° ± 12°. The average American Shoulder and Elbow Surgeons score was 86.8 ± 19.0, and the average visual analog scale score was 1.3 ± 2.4. Metallic debris was found in 9 shoulders (27%), and radiolucency was observed around the glenoid components in 13 shoulders (39%) on the final postoperative radiographs. Metallic debris and radiolucency findings were low in severity, with average grades of 0.32 (standard deviation, 0.54) and 0.39 (standard deviation, 0.50), respectively. There were no reoperations.

CONCLUSION

This study of 37 shoulders undergoing TSA with a TM-backed glenoid demonstrated 100% implant survivorship at an average follow-up of 7 years. Clinical outcomes were excellent despite the occurrence of some metallic debris formation. The findings suggest that a TM-backed glenoid component implanted in an inset fashion to achieve full backside support can provide good clinical and patient-reported outcomes in TSA patients at mid-term follow-up and suggest that continued consideration of the role of TM-backed glenoids and the optimal technique for implantation may be warranted.

Two-year results of a multi-centre, randomized controlled trial comparing a second-generation uncemented trabecular metal-backed versus cemented polyethylene glenoid component in total shoulder arthroplasty

Aims

To report early (two-year) postoperative findings from a randomized controlled trial (RCT) investigating disease-specific quality of life (QOL), clinical, patient-reported, and radiological outcomes in patients undergoing a total shoulder arthroplasty (TSA) with a second-generation uncemented trabecular metal (TM) glenoid versus a cemented polyethylene glenoid (POLY) component.

Methods

Five fellowship-trained surgeons from three centres participated. Patients aged between 18 and 79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Patients were randomized intraoperatively to either a TM or POLY glenoid component. Study intervals were: baseline, six weeks, six-, 12-, and 24 months postoperatively. The primary outcome was the Western Ontario Osteoarthritis Shoulder QOL score. Radiological images were reviewed for metal debris. Mixed effects repeated measures analysis of variance for within and between group comparisons were performed.

Results

A total of 93 patients were randomized (46 TM; 47 POLY). No significant or clinically important differences were found with patient-reported outcomes at 24-month follow-up. Regarding the glenoid components, there were no complications or revision surgeries in either group. Grade 1 metal debris was observed in three (6.5%) patients with TM glenoids at 24 months but outcomes were not negatively impacted.

Conclusion

Early results from this RCT showed no differences in disease-specific QOL, radiographs, complication rates, or shoulder function between uncemented second-generation TM and cemented POLY glenoids at 24 months postoperatively. Revision surgeries and reoperations were reported in both groups, but none attributed to glenoid implant failure. At 24 months postoperatively, Grade 1 metal debris was found in 6.5% of patients with a TM glenoid but did not negatively influence patient-reported outcomes. Longer-term follow-up is needed and is underway.

Cite this article: Bone Jt Open 2021;2(9):728–736.

Radiographic and clinical outcomes of second generation Trabecular Metal™ glenoid components in total shoulder arthroplasty

BACKGROUND

Total shoulder arthroplasty with second generation porous tantalum glenoid implants (Trabecular Metal™) has shown good short-term outcomes, but mid-term outcomes are unknown. This study describes the clinical, radiographic, and patient-rated mid-term outcomes of total shoulder arthroplasty utilizing cemented Trabecular Metal™ glenoid components.

METHODS

Patients who underwent anatomic total shoulder arthroplasty with cemented Trabecular Metal™ glenoid components for primary osteoarthritis were identified for minimum five-year follow-up. The primary outcome measure was implant survival; secondary outcome measures included patient-rated outcome scores, shoulder range of motion findings, and radiographic analysis.

RESULTS

Twenty-seven patients were enrolled in the study. Twenty-one patients had full radiographic follow-up. Mean follow-up was 6.6 years. There was 100% implant survival. Shoulder range of motion significantly improved and the mean American Shoulder and Elbow Society score was 89.8. There was presence of metal debris radiographically in 24% of patients. Twenty-nine percent of patients had evidence of radiolucency. Fourteen percent of patients had moderate superior subluxation.

CONCLUSION

Total shoulder arthroplasty with second generation cemented Trabecular Metal™ glenoid components yielded good outcomes at mean 6.6-year follow-up. Metal debris incidence and clinical outcomes were similar to short-term findings. The presence of metal debris did not significantly affect clinical outcomes. Continued observation of these patients will elucidate longer-term implant survival.

The Clinical Application of Porous Tantalum and Its New Development for Bone Tissue Engineering

Porous tantalum (Ta) is a promising biomaterial and has been applied in orthopedics and dentistry for nearly two decades. The high porosity and interconnected pore structure of porous Ta promise fine bone ingrowth and new bone formation within the inner space, which further guarantee rapid osteointegration and bone-implant stability in the long term. Porous Ta has high wettability and surface energy that can facilitate adherence, proliferation and mineralization of osteoblasts. Meanwhile, the low elastic modulus and high friction coefficient of porous Ta allow it to effectively avoid the stress shield effect, minimize marginal bone loss and ensure primary stability. Accordingly, the satisfactory clinical application of porous Ta-based implants or prostheses is mainly derived from its excellent biological and mechanical properties. With the advent of additive manufacturing, personalized porous Ta-based implants or prostheses have shown their clinical value in the treatment of individual patients who need specially designed implants or prosthesis. In addition, many modification methods have been introduced to enhance the bioactivity and antibacterial property of porous Ta with promising in vitro and in vivo research results. In any case, choosing suitable patients is of great importance to guarantee surgical success after porous Ta insertion.

Cemented versus uncemented fixation of second-generation Trabecular Metal glenoid components: minimum 5-year outcomes

BACKGROUND

Total shoulder arthroplasty (TSA) with second-generation Trabecular Metal™ implants (Zimmer, Warsaw, IN, USA) has shown good short-term outcomes. Differences in outcomes between cemented and uncemented fixation are unknown. This study compared the clinical, radiographic, and patient-rated outcomes of TSA with cemented vs. uncemented TM glenoids at minimum 5-year follow-up.

METHODS

Patients who underwent anatomic TSA with second-generation TM glenoid components for primary osteoarthritis were identified for minimum 5-year follow-up. The patients were divided into 2 groups: cemented and uncemented glenoid fixation. Outcome measures included implant survival, patient-rated outcome scores (Patient-Reported Outcomes Measurement Information System [PROMIS] and American Shoulder and Elbow Surgeons scores), shoulder range of motion, and radiographic analysis. Findings were compared between groups.

RESULTS

The study included 55 shoulders: 27 in the cemented group (21 with full radiographic follow-up) and 28 in the uncemented group (22 with full radiographic follow-up). Both groups had similar follow-up times (6.6 years in cemented group vs. 6.7 years in uncemented group, P = .60). Moreover, the groups did not differ significantly in sex composition, age at the time of surgery, or preoperative Walch glenoid grade distribution. No patients required revision surgery. The 2 groups had similar preoperative range of motion, but patients in the uncemented group had greater follow-up forward flexion (P = .03), external rotation (P < .01), and lateral elevation (P = .03) than did patients in the cemented group. PROMIS scores were not significantly different between groups. American Shoulder and Elbow Surgeons scores were similar (89.8 in cemented group vs. 94.1 in uncemented group, P = .21). Mid-term radiographs showed a metal debris rate of 24% in the cemented group and 27% in the uncemented group. Although these values were not significantly different (P = .90), the frequency of mild metal debris (grade 1-2), when present, was greater in the uncemented group (grade 2 in 6 shoulders) than in the cemented group (grade 1 in 4 and grade 2 in 1, P = .02). There was a greater presence of mild (grade 1) radiolucent lines in the uncemented group (64%) than in the cemented group (29%, P < .01). No glenoid had evidence of loosening (defined by a change in position or radiolucent lines > 2 mm). The presence of metal debris and radiolucent lines did not have a significant effect on clinical outcomes.

CONCLUSION

At minimum 5-year follow-up, TSA patients with TM glenoids demonstrated excellent clinical and patient-reported outcomes with a 100% implant survival rate, regardless of cemented vs. uncemented fixation. However, the uncemented group showed a significantly higher rate of radiolucent lines and a higher frequency of mild metal debris. These radiographic findings did not affect the clinical outcomes, and their implications for long-term outcomes and prosthesis survival is unknown.

Modern trabecular metal-backed glenoid components in total shoulder arthroplasty: What is the evidence? A systematic review

BACKGROUND

A number of papers have been published reporting on the clinical performance of modern trabecular metal-backed glenoid components in total shoulder arthroplasty. However, no systematic review of the literature has been published to date.

METHODS

The US National Library of Medicine (PubMed/MEDLINE), and the Cochrane Database of Systematic Reviews and EMBASE were queried for publications from January 1980 to October 2019 utilizing keywords pertinent to total shoulder arthroplasty, trabecular metal, and clinical outcomes.

RESULTS

Overall, seven articles were included for analysis (322 operated shoulders, mean follow-up range: 2-4 years). The survival rate of modern trabecular metal-backed glenoid components was 96% (309 out of 322 cases) at 43 months mean follow-up, while the rate of aseptic loosening was 0.3% (1 out of 322 cases). There were 35 cases (10.9%) with glenoid component radiolucency (one of them required revision), and 37 cases (11.5%) of metal debris formation, with four of them undergoing revision.

CONCLUSIONS

There was low quality evidence to show that the use of modern trabecular metal-backed glenoid components in total shoulder arthroplasty may be safe and effective at short-term follow-up. However, this analysis showed alarmingly high rates of both radiolucency of the glenoid component and metal debris formation which raise concern for potential failure of this glenoid component in the long term. Therefore, we feel that modern trabecular metal-backed glenoid components should be still used with caution as part of a structured surveillance or research program until we know if there is a detriment to the prosthesis in the medium to long term.Level: Systematic review, IV.

Do Modern Designs of Metal-Backed Glenoid Components Show Improved Clinical Results in Total Shoulder Arthroplasty? A Systematic Review of the Literature

Background:

Despite the increased popularity of reverse total shoulder arthroplasty, total shoulder arthroplasty is the standard treatment for advanced shoulder arthritis in young adult patients. Conventional metal-backed glenoid (MBG) designs result in more loosening and revision surgery compared with cemented polyethylene glenoid components. However, modern MBG designs have been recently devised to overcome such drawbacks.

Purpose:

To compare the radiolucency, loosening, and failure rates of modern MBG designs with those of conventional designs.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A search for relevant articles was carried out using the PubMed, Cochrane Library, and Embase databases using MeSH (Medical Subject Headings) terms and natural keywords. A total of 362 articles were screened. We descriptively analyzed numerical data between the groups and statistically analyzed categorical data, such as the presence of loosening, failure, and revision surgery. The main outcome was the rate of revision surgery or failure. Subgroup analysis according to follow-up duration was performed to reduce heterogeneity.

Results:

A total of 25 articles (2036 shoulders) were included; 15 articles (1579 shoulders) involved a conventional MBG design, and 10 (457 shoulders) involved a modern design. The mean age of the patients was 64.2 and 66.5 years in the conventional and modern design groups, respectively, with a mean follow-up duration of 102.0 and 56.1 months, a mean gain of forward elevation of 35.1° and 61.7°, and a mean gain of external rotation of 24.2° and 39.2°. The rate of radiolucency was 48.0% and 16.7%, the rate of loosening was 11.2% and 4.9%, and the rate of revision was 15.9% and 2.4%, for the conventional and modern design groups, respectively. Subgroup analysis according to follow-up duration showed that the rates of loosening and revision were significantly lower in the modern design group (P < .001).

Conclusion:

Our findings suggest that modern MBG designs showed significantly lower loosening and failure rates than conventional designs. The overall results of the comparison, including loosening, failure, change in range of motion, and clinical scores, indicate that modern MBG designs are promising. More long-term follow-up studies on modern MBGs should be conducted.

The association between glenoid component design and revision risk in anatomic total shoulder arthroplasty

INTRODUCTION

Anatomic total shoulder arthroplasty (TSA) is a proven treatment for glenohumeral joint osteoarthritis, with superior results compared with hemiarthroplasty. However, glenoid component loosening remains a problem and is one of the most common causes of failure in TSA. Multiple component designs have been developed in an attempt to reduce loosening rates. The purpose of this study was to evaluate risk of revision after anatomic TSA according to the glenoid component design.

METHODS

We conducted a cohort study including patients aged ≥18 years who underwent primary elective TSA for the diagnosis of osteoarthritis between 2010 and 2017. Patients with missing implant information, who received stemless humeral implants, or who received augmented glenoid implants, were excluded. Glenoid component designs used were categorized into 4 mutually exclusive treatment groups: polyethylene central-pegged ingrowth, polyethylene-metal hybrid, polyethylene all-cemented pegged, and polyethylene cemented keeled. Multivariable competing risk regression was used to evaluate the risk of glenoid loosening as a cause-specific revision by the glenoid component design.

RESULTS

Of the 5566 TSA included in the final cohort, 39.2% of glenoid implants were polyethylene central-pegged ingrowth, 31.1% were polyethylene-metal hybrid, 26.0% were polyethylene all-cemented pegged, and 3.6% were polyethylene cemented keeled. At 6-year final follow-up, 4.1% of TSA were revised for any cause, and 1.4% for glenoid loosening. Compared with the polyethylene central-pegged ingrowth design, no difference in glenoid loosening revision risk was observed for the polyethylene-metal hybrid design (hazard ratio [HR] = 1.15, 95% confidence interval [CI] = 0.42-3.20). However, both the polyethylene all-cemented pegged (HR = 2.48, 95% CI = 1.08-5.66) and polyethylene cemented keeled (HR = 3.84, 95% CI = 1.13-13.00) designs had higher risks for revision due to glenoid loosening.

CONCLUSIONS

We observed glenoid component designs to be associated with differential risks in revision due to glenoid loosening with polyethylene all-cemented pegged glenoids and polyethylene cemented keeled glenoids having higher risks when compared with polyethylene central-pegged ingrowth glenoids. Surgeons may want to consider the glenoid component design when performing anatomic TSA.

Loosening and revision rates after total shoulder arthroplasty: a systematic review of cemented all-polyethylene glenoid and three modern designs of metal-backed glenoid

BACKGROUND

Several modern designs of metal-backed glenoids (MBG) have been devised to overcome flaws such as loosening and a high failure rate. This review aimed to compare rates of complications and revision surgeries between cemented polyethylene glenoid (PEG) and three examples of modern MBG designs.

METHODS

Literature search was carried out using PubMed, Cochrane Library, EMBASE, and Google Scholar using MeSH terms and natural keywords. A total of 1186 articles were screened. We descriptively analyzed numerical data between the groups and statistically analyzed the categorical data, such as the presence of radiolucent line, loosening, and revision surgery (failure). Articles were divided into three groups based on follow-up duration: < 36-month, 36-72-month, and > 72-month subgroups.

RESULTS

This study included 35 articles (3769 shoulders); 25 on cemented PEG and ten on the modern MBG. Mean age was 66.4 (21-93) and 66.5 years (31-88). The mean duration of follow-up was 73.1 (12-211) and 56.1 months (24-100). Overall, the rate of the radiolucent line was 354/1302 (27%) and 47/282 (17%), the loosening rate was 465/3185 (15%) and 22/449 (5%), and the failure rate was 189/3316 (6%) and 11/457 (2%), for PEG and MBG, respectively. The results of < 36-month and 36-72-month subgroups showed lower rates of radiolucency and loosening in the cemented PEG group, but there was no significant difference in failure rate (P = 0.754 and 0.829, respectively). In the > 72-month subgroup, MBG was better in terms of loosening (P < 0.001) and failure rates (P = 0.006).

CONCLUSIONS

The modern MBG component, especially TM glenoid, seems to be a promising alternative to cemented PEGs, based on subgroup revision rates according to the follow-up duration and overall results of ROM and clinical scores. All polyethylene glenoids tend to increase loosening and failure over time. Three modern MBG designs seem to have no difference in failure, at least in the < 36-month and 36-72-month subgroups compared to the cemented PEG. More long-term follow-up studies on modern MBG should be ultimately conducted.

LEVEL OF EVIDENCE

Level IV, systematic review.

Porous Tantalum and Titanium in Orthopedics: A Review

Porous metal is metal with special porous structures, which can offer high biocompatibility and low Young's modulus to satisfy the need for orthopedic applications. Titanium and tantalum are the most widely used porous metals in orthopedics due to their excellent biomechanical properties and biocompatibility. Porous titanium and tantalum have been studied and applied for a long history until now. Here in this review, various manufacturing methods of titanium and tantalum porous metals are introduced. Application of these porous metals in different parts of the body are summarized, and strengths and weaknesses of these porous metal implants in clinical practice are discussed frankly for future improvement from the viewpoint of orthopedic surgeons. Then according to the requirements from clinics, progress in research for clinical use is illustrated in four aspects. Various creative designs of microporous and functionally gradient structure, surface modification, and functional compound systems of porous metal are exhibited as reference for future research. Finally, the directions of orthopedic porous metal development were proposed from the clinical view based on the rapid progress of additive manufacturing. Controllable design of both macroscopic anatomical bionic shape and microscopic functional bionic gradient porous metal, which could meet the rigorous mechanical demand of bone reconstruction, should be developed as the focus. The modification of a porous metal surface and construction of a functional porous metal compound system, empowering stronger cell proliferation and antimicrobial and antineoplastic property to the porous metal implant, also should be taken into consideration.

Comparison of revision rates and radiographic observations of long and short, uncoated and coated humeral stem designs in total shoulder arthroplasty

There is no consensus on outcomes of long versus short and uncoated versus coated uncemented stems in total shoulder arthroplasty (TSA).

We reviewed the literature to compare revision rates and adverse radiographic observations at ⩾ 2 years of various uncemented humeral stem designs.

We performed an electronic PubMed search for studies on uncemented primary TSA that reported one or more of the following observations at ⩾ 2 years for distinct stem designs: stem revision; subsidence; stress shielding; radiolucent lines; and humeral loosening.

The search returned 258 records, from which 20 articles (22 cohorts) met the inclusion criteria.

The most frequently reported designs were short uncoated stems (7/13 cohorts) at < 3 years and long uncoated stems (8/9 cohorts) at > 3 years.

The incidences of revisions and adverse radiographic observations were lower for short coated designs, compared with short and long uncoated designs, but these findings should be confirmed by prospective studies with a longer follow-up.

Cite this article: EFORT Open Rev 2019;4:70-76. DOI: 10.1302/2058-5241.4.180046.

Restoration of the joint geometry and outcome after stemless TESS shoulder arthroplasty

AIM

To evaluate the joint geometry and the clinical outcome of stemless, anatomical shoulder arthroplasty with the TESS system.

METHODS

Twenty-one shoulders with a mean follow-up 18 of months were included. On scaled digital radiographs the premorbid center of rotation (CoR) was assessed and compared to the CoR of the prosthesis by using the MediCAD^® software. Additionally, the pre- and post-operative geometry of the CoR was assessed in relation to the glenoid, the acromion as well as to the proximal humerus. Radiological changes, such as radiolucencies, were also assessed. Clinical outcome was assessed with the Constant and DASH score.

RESULTS

Both, the Constant and DASH scores improved significantly from 11% to 75% and from 70 to 30 points, P < 0.01 respectively. There were no significant differences regarding age, etiology, cemented or metal-backed glenoids, etc. (P > 0.05). The pre- and postoperative humeral offset, the lateral glenohumeral offset, the height of the CoR, the acromiohumeral distance as well as neck-shaft angle showed no significant changes (P > 0.05). The mean deviation of the CoR of the prosthesis from the anatomic center was 1.0 ± 2.8 mm. Three cases showed a medial deviation of more than 3 mm. These deviations of 5.1, 5.7 and 7.6 mm and were caused by an inaccurate humeral neck cut. These 3 patients showed a relatively poor outcome scoring.

CONCLUSION

TESS arthroplasty allows an anatomical joint reconstruction with a very good outcome. Outliers described in this study sensitize the surgeon for an accurate humeral neck cut.