Stemless Prosthesis Research Articles

The biomechanical assessment of two stemless shoulder arthroplasty prostheses in uniformly poor-quality bone mineral density cadaveric specimens

BackgroundStemless shoulder arthroplasty offers several advantages, such as preserving bone stock and reducing periprosthetic fracture risk. However, implant motion can deter osteointegration and increase bone resorption, where micromotion less than 0.150 mm is crucial for bony ingrowth and vital to the success of the implant. The interaction between the implant and the metaphyseal bone and its effects on stability remains unclear. Therefore, this cadaveric study aims to assess the immediate stability of two stemless prostheses in low bone density specimens. MethodsTwenty cadaveric shoulders were used to compare the stability of two stemless shoulder implants by Zimmer-Biomet (model A) and Exactech (model B), subjected to loads of 220 N, 520 N, and 820 N to assess strain and micromotion. FindingsMicromotion at 220 N load was 0.061 ± 0.080 mm and 0.053 ± 0.050 mm, and at 520 N load, 0.279 ± 0.37 mm and 0.311 ± 0.35 mm for models A and B, respectively. The estimated mean force required to achieve a 150 μm micromotion was 356 ± 116 N and 315 ± 61 N for models A and B, respectively. Motion analysis revealed distinct movement patterns for each implant, with model B demonstrating better force distribution on the bone despite no significance. InterpretationForces over 520 N (high postoperative rehabilitation force) could hinder bone integration with prostheses due to excessive micromotion. Conversely, forces around 220 N (preconditioning loading force) are considered safe for prosthesis stability even with low bone density. These insights may caution against using stemless implants when bone density is low, and help guide clinical decisions on the duration of rehabilitation and sling use after stemless arthroplasty.

Lower deltoid tuberosity indices are associated with the use of a stemmed instead of a preoperatively planned stemless implant

BackgroundAnatomic total shoulder arthroplasty (TSA) using a stemless prosthesis continues to increase in popularity as literature supporting their use grows. Intraoperative findings, however, may require switching from a planned stemless prosthesis to using a stemmed implant, yet literature attempting to understand the incidence and risk factors leading to this outcome is limited. The purpose of this study was to document the incidence of intraoperative change from a planned stemless implant to a stemmed prosthesis and to determine the correlation between the deltoid tuberosity index and this decision. MethodsAll patients scheduled to undergo TSA with a stemless humeral prosthesis between 2018 and 2023 at a single academic institution were retrospectively reviewed. Sociodemographic data, comorbidities, and preoperative deltoid tuberosity indices (DTI) were collected for review. DTI was used as an approximation for a patient’s bone mineral density. Surgeon plan for stemless TSA was verified via saved three-dimensional preoperative plans. ResultsNinety-two patients were scheduled to undergo stemless TSA, 8 (8.70%) of which received a stemmed implant based on intraoperative findings. In all cases, the operative surgeon deemed the metaphyseal bone inadequate to facilitate use of a stemless implant. DTI was significantly higher in the stemless group relative to the stemmed group (1.55 vs. 1.37, P = .0023). Discussion and ConclusionApproximately 9% of planned stemless TSA were converted to stemmed TSA due to proximal humerus bone insufficiency based on surgeon assessment at time of surgery. Diminished DTI was noted to be a risk factor. Preoperative planning may be improved by including imaging parameters to assess bone sufficiency (eg, DTI).

A survey and biomechanical analysis of the feasibility of the thumb test for determining the cancellous bone quality for stemless shoulder prosthesis.

The effect of the thumb test for assessing the cancellous bone quality at the resection plane of the proximal humerus on determining the application of a stemless shoulder prosthesis remains unclear. This study was conducted to survey the current utilization of the thumb test among surgeons and to investigate biomechanical features of the thumb test. A survey among shoulder surgeons who had experience with stemless prostheses was conducted to investigate the current utilization of preoperative assessments and intraoperative thumb test when applying stemless prosthesis. Biomechanical experiments for the thumb test using artificial bone models were performed to assess the compression force, contact pressure and area. According to the preliminary survey, three compression techniques were assessed: compression perpendicular to the surface with thumb pad (P-pad technique) or tip of the thumb (P-tip technique), or compression in the vertical direction simulating compression along the longitudinal axis of the humeral shaft with tip-pad of the thumb (H-axis technique). The contact area was separated into three subregions (proximal, middle and distal) to assess the distribution of contact pressure. Among 38 surgeons, 66% utilized the thumb test intraoperatively. The P-pad technique was more frequently applied than the P-tip or H-axis techniques (80%, 4% and 16%, respectively). Although with wide variation among the examiners, biomechanical assessments revealed the P-pad technique showed larger contact area and less compression force than the P-tip technique. The P-pad technique provided no significant localized differences in the mean contact pressure on the compressed plane, whereas the P-tip and H-axis techniques showed significant differences among subregions. This survey demonstrated relatively frequent application of the thumb test on applying the stemless shoulder prosthesis. Biomechanical assessment revealed the thumb test can hinder objective reproducibility among examiners; therefore, further investigations to identify feasible assessments of the bone quality is required.

Is stemless total shoulder arthroplasty indicated in elderly patients?

Stemmed anatomic total shoulder arthroplasty has represented the gold standard for the treatment of glenohumeral osteoarthritis with an intact rotator cuff for decades. To the author's knowledge, no study has specifically examined the outcomes of stemless, modular total shoulder arthroplasty in elderly patients. The hypothesis of this study was that stemless anatomic total shoulder arthroplasty in elderly patients (age ≥70 years) would have equivalent clinical and radiographic outcomes compared with a younger population (age <70 years). A prospectively collected database of patients undergoing primary, modular, stemless anatomic total shoulder arthroplasty for osteoarthritis was retrospectively reviewed. Patient-determined outcomes including the Western Ontario Osteoarthritis Index (WOOS) score, American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numeric Evaluation (SANE) score, Simple Shoulder Test score, and Shoulder Activity Level score were recorded preoperatively and postoperatively at 1 year and 2 years. Preoperative and 1-year postoperative range of motion was recorded. Postoperative radiographs were examined to assess for radiographic evidence of complications. Stemless arthroplasty was planned in 116 patients. Seven patients underwent conversion intraoperatively to a stemmed prosthesis. There was no difference between patients aged <70 yr and those aged ≥70 years who required intraoperative deviation from the preoperative plan to a stemmed prosthesis (5.8% vs 6.4%, P=.90). At the time of stemless arthroplasty, 64 patients were aged <70 yr and 44 patients were aged ≥70 years. Between the 2 groups, there were no clinically or statistically significant differences in WOOS, ASES, and SANE scores at baseline, 1-year follow-up, or 2-year follow-up. The changes in all scores from baseline to 2 years were similar between the group aged <70 yr and the group aged ≥70 years. There was no difference in the percentage of patients achieving the minimal clinically important difference or substantial clinical benefit in either group after shoulder arthroplasty at 2-year follow-up. There was no difference between the 2 groups in terms of final postoperative range of motion or change in range of motion for any metric examined. There was no evidence of radiographic complications in either group. Age ≥70 years does not appear to be a contraindication to stemless anatomic total shoulder arthroplasty. Postoperative improvements in patient-determined outcome scores, the percentage of patients achieving clinically important outcomes for the ASES, SANE, and WOOS scores, and postoperative range of motion were similar between patients aged <70 yr and those aged ≥70 years. There was no difference between the groups regarding the patients who required intraoperative deviation from the preoperatively planned stemless prosthesis to a stemmed prosthesis. Neither age group demonstrated a radiographically apparent complication.

Lesser Tuberosity Osteotomy Healing in Stemmed and Stemless Anatomic Shoulder Arthroplasty Is Higher with a Tensionable Construct and Affected by Body Mass Index and Tobacco Use.

This study compared the healing rates of lesser tuberosity osteotomy (LTO) for anatomic total shoulder arthroplasty (TSA), repaired with either standard knot tying or a tensionable construct. Second, we evaluated LTO healing in stemmed and stemless prostheses and identified the patient characteristics associated with healing. An analysis of consecutive primary TSAs approached with an LTO performed by a single surgeon between 2016 and 2020 was conducted. In the first two years of the study period, the LTOs were repaired with four #2 polyblend sutures passed through drill tunnels and around a short press-fit stem, followed by manual knot tying. Subsequently, a tensionable construct with suture tapes (TCB) was universally adopted. The radiographic appearance of the LTO was evaluated at a minimum of six months postoperatively. A total of 340 patients met the study criteria, including 168 with manual knot tying, 84 TCB repairs with a stemmed implant, and 88 TCB repairs with a stemless implant. There was no difference in the baseline demographics between the groups. The LTO healing rate of the manual knot tying group (85%) was lower than that of the stemmed (95%) and stemless (98%) TCB groups (p < 0.001). When directly comparing the LTO healing between the stemmed and stemless TCB groups, the differences were not significant (p = 0.44). Across all constructs, the body mass index (BMI) was higher in the displaced nonunion group (p = 0.04), with a failure rate of 9.4% for a BMI between 30 and 40, 12.5% for a BMI between 40 and 50, and 28.6% for a BMI > 50. The rate of tobacco use was higher in the displaced nonunion group (p = 0.037). A tensionable construct improves LTO healing compared to manual knot tying, irrespective of the implant type. In addition to the surgical technique, the patient factors that influence tuberosity healing include a greater BMI and tobacco use. Level III, retrospective comparative study.

Stemless components lead to improved radiographic restoration of humeral head anatomy compared with short-stemmed components in total shoulder arthroplasty

Restoring the native center of rotation (COR) in total shoulder arthroplasty (TSA) has been shown to improve postsurgical function, subjective outcomes, and implant longevity. The primary purpose of this study was to compare postoperative radiographic restoration of the humeral COR between short-stem and stemless humeral implants by evaluating the mean COR shift between the 2 techniques. Secondary outcomes evaluated were comparisons of COR shift outliers, humeral head implant thickness and diameter, direction of COR shift, and neck-shaft angle (NSA). This study was a multicenter retrospective comparative study using a consecutive series of primary anatomic TSA patients who received either a short-stem or stemless humeral implant. Radiographically, COR and NSA were measured by 2 fellowship-trained surgeons using the best-fit circle technique on immediate postoperative Grashey radiographs. A total of 229 patients formed the final cohort for analysis that included 89 short stems and 140 stemless components. The mean COR shift for short stems was 2.7 mm (±1.4 mm) compared with 2.1 mm (±0.9 mm) for stemless implants (P<.001). The percentage of short-stem implant patients with a >2 mm COR difference from native was 66.0% (n=62) compared with 47.4% (n=64) for stemless (P=.006). The percentage of short-stem patients with a >4 mm COR difference from native was 17.0% (n=16) compared with 3.0% (n=4) for stemless (P<.001). The mean humeral implant head thickness for short stems was 18.7±2.2 mm compared with 17.2±1.3 mm for stemless implants (P<.001). The mean humeral head diameter for short stems was 48.7±4.4 mm compared with 45.5±3.5 mm for stemless implants (P<.001). The NSA for the short-stem cohort was 136.7° (±3.6°) compared with 133.5° (±6.0°) for stemless (P<.001). Stemless prostheses placed during TSA achieved improved restoration of humeral head COR and were less likely to have significant COR outliers compared with short-stem implants.

Stemless and stemmed total shoulder arthroplasty: a comparison of short-term clinical and radiographic outcomes

BackgroundStemless total shoulder arthroplasty could provide benefits over stemmed arthroplasty which has represented the gold standard for decades. Proposed benefits of stemless arthroplasty include better reproduction of anatomy and reduction in stress shielding; however, this does not appear to be confirmed by any study. The hypothesis was there would be no clinical differences between the stemless and the short-stem prosthesis, but the stemless prosthesis would better reproduce coronal radiographic anatomy and have less radiographic evidence of stress shielding. Materials and MethodsA prospectively collected data of patients undergoing primary, anatomic total shoulder arthroplasty for osteoarthritis were retrospectively reviewed. Patient-determined outcomes including the Western Ontario Osteoarthritis Index, American Shoulder and Elbow Surgeons score, Single Assessment Numeric Evaluation, Simple Shoulder Test, and Shoulder Activity Level were recorded preoperatively, at 1 year, and at 2 years. Preoperative and 1-year postoperative range of motion was recorded. Radiographic parameters to assess restoration of proximal humeral anatomy included humeral head height, humeral neck angle, humeral centering on the glenoid, and postoperative restoration of the anatomic center of rotation. Final postoperative radiographs were assessed for evidence of stress shielding. ResultsForty-eight patients had a stemmed humeral prosthesis, and 109 patients had a stemless prosthesis. Patient-determined outcomes were available from 2 years postoperatively in 99.4%. Both groups had significant improvements in all patient-reported outcomes and range-of-motion metrics, but there were no differences between the stemless and stemmed groups in these outcomes. The prosthetic humeral head of the stemmed components was more likely to extend further superior to the humeral osseous margin than that of the stemless group (2.0 ± 2.4 vs. 0.8 ± 1.4 mm; P = .0004). The stemless group had a smaller postoperative deviation from the anatomic center of rotation than the stemmed group (2.5 ± 1.9 vs. 3.2 ± 2.1 mm; P = .04). The humeral neck angle was comparable between the stemmed group and the stemless group (133 ± 7° vs. 131 ± 8°; P = .06). There was similar mean deviation of humeral head centering on the glenoid prosthesis between the stemmed and stemless groups (1.9 ± 1.8 vs. 1.6 ± 1.7 mm; P = .20). There was evidence of stress shielding in 10 patients (21%) with a stemmed prosthesis and in no patients with a stemless prosthesis at 1-year follow-up (P < .0001). ConclusionsThere were no differences in patient-determined outcomes between the groups at 2-year follow-up. Restoration of proximal humeral anatomy was either better or equivalent with the stemless prosthesis compared to the stemmed one. Radiographic evidence of stress shielding was found in the stemmed prosthesis but not in the stemless prosthesis at 1-year follow-up.

Proximal humeral bone loss in stemless shoulder arthroplasty: potential factors influencing bone loss and a new classification system.

Proximal humeral bone loss in total shoulder arthroplasty (TSA) is more frequent than in hemiarthroplasty. Factors such as age, gender, inclination angle, and radiolucent lines may also contribute. Additionally, current bone loss grading systems are often not sensitive enough to detect slight bone changes, especially at the medial calcar where bone loss is commonly observed. This study uses a new, more detailed bone loss grading system to evaluate factors that could influence bone loss at the proximal humerus. In this single-center prospective study, patients underwent hemiarthroplasty or TSA with an anatomic stemless prosthesis. Bone loss was measured at the proximal humerus using the new grading system. The effect of treatment type, age, gender, radiolucent lines, and inclination angle on bone loss was evaluated. The Constant-Murley score of patients was assessed and complications recorded. Ninety-one shoulders were available for the final follow-up examination at a median of 85.0months (range 82.6-121.1months). Bone loss was found at the proximal humerus in approximately one-third of shoulders, and significantly more shoulders had bone loss in TSA than in hemiarthroplasty (P = 0.03). However, this difference was no longer significant after stratifying by gender and age (P > 0.05). Bone loss significantly correlated with gender (P = 0.03) but not with treatment type, radiolucent lines, and the postoperative inclination angle (P > 0.05). Most Constant-Murley score components did not differ significantly between shoulders with and without bone loss (P > 0.05). Lastly, six complications and four revisions were reported. Results showed gender had the greatest influence on bone loss after stemless shoulder arthroplasty. Furthermore, both patients with or without bone loss can expect similar clinical outcomes with the stemless prosthesis used in this study. Lastly, the new grading system is simple and straightforward to use.

Is Stemless A Viable Treatment Option In Total Shoulder Arthroplasty?

To assess clinical and radiographic outcomes of a novel design of stemless prosthesis, evaluating patient recovery and implant stability.

Assessment of intraoperative bleeding in reverse shoulder arthroplasty – with or without a stem

IntroductionThe functional results of stemless reverse shoulder prostheses are similar to those with stems. However, the operative time and the bleeding appear less significant because of the absence of humeral reaming. To date, the data amongst the literature regarding this subject is limited. Thus, we report a retrospective evaluation on these 2 types of prostheses by assessing their respective intraoperative blood loss. HypothesisReverse shoulder arthroplasty without a stem leads to less blood loss, compared to arthroplasty with a stem. Materials and methodsTwenty-three patients underwent an operation for a stemless prosthesis, while 37 patients had a prosthesis with a stem. The hemoglobin was measured preoperatively, as well as postoperatively. Drainage of the operative site was maintained for two to three days. In the stem group, the preoperative hemoglobin was 14g/dL (11.7–16.6), while it was 13.1g/dL (11–15.8) in the stemless group. ResultsThe intraoperative bleeding reached 223cm3 (80–530), with an operative duration of 81minutes (40–110) in the stemless group, compared to 260cm3 (50–1000) and 92minutes (33–110) in the stem group. On the first day postoperatively, 333cm3 (20–570) of blood had been collected by drainage for the stemless group, compared to 279cm3 (40–550) in the stem group. The amount decreased the second day, with 139cm3 (20–510) and 129cm3 (0–750) respectively. There was no difference between the two groups regarding the postoperative hemoglobin level (11g/dL). DiscussionThere is no significant difference concerning the blood loss between reverse shoulder replacements with and without stems. Level of evidenceIII Retrospective case control study

Postoperative Trends of Serum C-Reactive Protein Levels after Primary Shoulder Arthroplasty-Normal Trajectory and Influencing Factors.

Background—Postoperative serum C-reactive protein (CRP) is an important diagnostic parameter for systemic inflammation and reflects surgical trauma. While trends and normal trajectories after total knee (TKA) or hip arthroplasty (THA) are established, there is no reference standard for shoulder arthroplasty (SA). Therefore, the aim of this study was to research CRP trends and influencing factors following SA. Methods—This retrospective study analyzed postoperative serum CRP levels and trajectories in 280 patients following SA. Influence of prosthesis design, sex, operating time, BMI, and humeral augmentation with bone cement were analyzed using descriptive statistics and (non-) parametric testing. Results—There is a CRP trend with a peak on day two or three, with a subsequent decrease until day seven. Reverse and stemmed prostheses show a statistically higher CRP peak than stemless prostheses or hemiarthroplasties (HA). There was no influence of gender, body mass index (BMI), operating time, or bone cement. Conclusion—The presented findings may contribute to a better understanding of the postoperative CRP course after SA. The results of this retrospective study should be validated by a prospective study design in the future.

Proximal humeral osteolysis and glenoid radiolucent lines in an anatomic shoulder arthroplasty: a comparison of a ceramic and a metal humeral head component

In vitro wear studies demonstrate decreased polyethylene wear with a ceramic compared with a metal humeral head. In this invivo study, we analyzed prospectively collected 5-year data, comparing the outcomes of 2 types of humeral implants. Sixty-two anatomic total shoulder arthroplasties (TSAs) (59 patients) were performed using the same glenoid component and 2 types of modular humeral implants (metal-head long-stem prosthesis in group A vs. ceramic-head stemless prosthesis in group B). Radiographic analysis for proximal humeral osteolysis and glenoid component radiolucent lines was performed at an average of 5.5 years. Functional outcomes were prospectively evaluated according to the visual analog scale score for pain; satisfaction level; American Shoulder and Elbow Surgeons score; active elevation; Shoulder Pain and Disability Index score; and Disabilities of the Arm, Shoulder and Hand score. There were 39 TSAs in group A (mean age, 68.1 years) and 23 TSAs in group B (mean age, 67 years). Clinical improvement was similar for both groups. Some proximal humeral osteolysis occurred in 56% of all TSAs. Group A showed increased osteolysis compared with group B (72% vs. 30%, P = .005). Glenoid radiolucent lines were far more frequent in group A, and group A showed a direct relationship between the extent of humeral osteolysis and the severity of glenoid radiolucent lines (P < .001). The stemless ceramic-head replacements showed fewer glenoid radiolucent lines and less humeral osteolysis than the long-stem metal-head replacements. In the group with metal-head replacements, correlation was shown between glenoid radiolucent lines and humeral osteolysis.

The short- to midterm effectiveness of stemless prostheses compared to stemmed prostheses for patients who underwent total shoulder arthroplasty: a meta-analysis

BackgroundTo systematically compare the short- to midterm effectiveness of stemless prostheses to that of stemmed prostheses for patients who underwent total shoulder arthroplasty (TSA) and to provide a guideline for clinical decision-making.MethodsPubMed, the Cochrane Library, and Web of Science were searched with the given search terms until July 2019 to identify published articles evaluating the clinical outcomes for stemless prostheses compared with stemmed prostheses for patients who underwent TSA. Data extraction and the quality assessment of the included studies were independently performed by two authors. Stata software 14.0 was used to analyze and synthesize the data.ResultsTwo randomized controlled trials and six case-controlled studies with a total of 347 shoulders were included in this meta-analysis. The results of this meta-analysis showed that there were no significant differences between the stemless and stemmed prostheses in terms of the Constant score, pain score, strength, activities of daily living, postoperative range of motion (ROM), and postoperative maximum active ROM.ConclusionsThis is the first meta-analysis reporting the clinical results of stemless TSA in the short- to midterm follow-up period. Both types of shoulder prostheses were similar in achieving satisfactory clinical outcomes.

Mid-term results with an anatomic stemless shoulder prosthesis in patients with primary osteoarthritis

ObjectiveThe introduction of a stemless prosthesis in shoulder arthroplasty represents a novel design whereby the proximal humerus is restored anatomically, while leaving the diaphysis of the humerus untouched. The aim of this study was to present the mid-term results of total evolutive shoulder system (TESS; Biomet®), a stemless shoulder prosthesis. MethodsThe study included 38 consecutive patients (18 men and 20 women; mean age: 66 years; range: 55-81 years) treated with shoulder arthroplasty between 2009 and 2011 with TESS for primary glenohumeral arthritis. Total shoulder arthroplasty (TSA) was performed in 28 cases (74%), hemi-shoulder arthroplasty (HSA) in 10 (26%). Constant score, active range of motion, patient satisfaction rate, and radiological assessment were analyzed. Mean time of follow-up was 37 months. ResultsConstant score improved from 21.8 points (28.6 adjusted for age) preoperatively to 74.1 points (86.6 adjusted for age) postoperatively. Active range of motion increased significantly from the pre- to postoperative status. Eighty-nine percent were very satisfied or satisfied with shoulder replacement surgery. One cemented glenoid was revised due to aseptic loosening. None of the components were found to be loose at the final follow-up. No signs of stress shielding were seen. ConclusionsThis study shows promising results of this implant concept in the short- to mid-term. These results are comparable with the results achieved with long-established arthroplasty designs. Level of EvidenceLevel IV, Therapeutic Study.

Clinical and radiologic outcomes following total shoulder arthroplasty using Arthrex Eclipse stemless humeral component with minimum 2 years' follow-up

Stemless humeral components benefit from less morbidity, better reproduction of the humeral anatomy, ease of revision, and fewer stem-related complications. Encouraging results are available up to 9 years after surgery from the designer's series. This is an independent study of 100 consecutive Eclipse stemless prostheses for osteoarthritis with a minimum 2-year follow-up (range, 2-6 years). We included only total shoulder arthroplasties performed for osteoarthritis. The primary outcome was the Oxford Shoulder Score (OSS) after 2 years. Secondary outcome measures were change in shoulder range of movement and radiographic analysis of prosthesis size and position. The mean OSS at 2 years was 38 of 48, with a mean improvement of +19 points (range, +17 to +22 points; P < .001). There was no significant deterioration in OSS after 3 or 4 years' follow-up. Statistically significant improvement was seen in arm elevation and external rotation (P < .001). There were 5 reoperations-1 for impingement of the biceps stump and 4 revisions to reverse arthroplasty for cuff failure. Of the prostheses, 92% were sized within 2 mm of the anatomic head size, and in 76% of prostheses, the center of rotation was within 3 mm of the native anatomy. An incomplete radiolucent line was present in zone B (around the cage screw) in a single patient at 2 years following surgery. There were no cases of loosening or infection. The functional and radiographic outcomes of Eclipse total shoulder replacement are excellent. We were able to accurately reproduce the native anatomy in the majority of cases, with no implant loosening, at 2 to 6 years' follow-up.

Anatomic shoulder arthroplasty

Arthroplasty has become a reliable treatment for degenerative joint diseases of the shoulder. Implant designs have developed over the last 60 years to address the initial problems encountered in arthroplasty: restoration of function and implant loosening. Although reverse shoulder arthroplasty (RSA) has become the most commonly performed type of shoulder replacement in the UK, total anatomical shoulder arthroplasty (TSA) has remained as a well-established treatment for osteoarthritis in patients with a competent rotator cuff. Patients with osteoarthritis treated with TSA can nowadays expect a lasting, significant improvement in pain and function. Nonetheless, controversies exist regarding the indications for humeral hemiarthroplasty and the use of stemless prostheses and other, newer implant designs. Interestingly, changes in the design of glenoid components have not led to significant improvements in clinical performance with time, and cemented all-polyethylene components remain the most reliable option. Lower glenoid aseptic loosening rates are probably best achieved by optimizing the restoration of natural humeral head anatomy.

Anatomic stemless shoulder arthroplasty and related outcomes: a systematic review.

BackgroundThe latest generation of shoulder arthroplasty includes canal-sparing respectively stemless designs that have been developed to allow restoration of the glenohumeral center of rotation independently from the shaft, and to avoid stem-related complications. The stemless prosthesis design has also recently been introduced for use in reverse arthroplasty systems.MethodsWe systematically reviewed the literature for studies of currently available canal-sparing respectively stemless shoulder arthroplasty systems. From the identified series, we recorded the indications, outcome measures, and humeral-sided complications.ResultsWe identified 11 studies of canal-sparing respectively stemless anatomic shoulder arthroplasty implants, published between 2010 and 2016. These studies included 929 cases, and had a mean follow-up of 26 months (range, 6 to 72 months). The rates of humeral component-related complications ranged between 0 and 7.9 %. The studies reported only a few isolated cases of complications of the humeral component. Some arthroplasty systems are associated with radiological changes, but without any clinical relevance.ConclusionsAll of the published studies of canal-sparing respectively stemless shoulder arthroplasty reported promising clinical and radiological outcomes in short to midterm follow-up. Long-term studies are needed to demonstrate the long-term value of these kind of implants.

Stemless shoulder prosthesis for treatment of proximal humeral malunion does not require tuberosity osteotomy.

When the proximal humeral anatomy is altered because of malunion, shoulder arthroplasty is a challenge for the orthopaedic surgeon, and tuberosity osteotomy should be avoided whenever possible. The purpose of this study was to investigate the clinical and radiological outcomes of anatomic stemless shoulder arthroplasty in cases of malunion. We hypothesized that a stemless prosthesis can be implanted without performing tuberosity osteotomy. We conducted a continuous, single surgeon, retrospective case series study with a minimum follow-up of twoyears (mean of 44months, range 24-80). The Constant-Murley score, active range of motion and X-rays were evaluated in 27 patients (mean age of 60years, range 37-83) with proximal humeral malunion who were treated with a stemless anatomic shoulder prosthesis. In all patients, the prosthesis was implanted without the need for tuberosity osteotomy. The Constant score improved from 27 to 62 (p ≤ 0.001), active anterior elevation from 81° to 129° (p ≤ 0.001), and external rotation from 5° to 40° (p ≤ 0.001). There was no evidence of radiological loosening. Use of a stemless anatomic shoulder prosthesis avoids the need for tuberosity osteotomy and certain surgical difficulties, even in cases of severe tuberosity malunion, and leads to good functional outcomes in the short term.

(ii) Hemiarthroplasty of the glenohumeral joint

Abstract Hemiarthroplasty of the humeral head is indicated for glenohumeral arthritis unresponsive to conservative measures and for some acute fractures of the proximal humerus. Regardless of indication, the functional result relies upon recreation of normal anatomy. In the elective setting, stemmed, stemless and surface replacement prostheses are available. Significant controversy exists regarding implant choice, and a longstanding debate concerning the choice of hemiarthroplasty versus total shoulder replacement continues. Complex fractures of the proximal humerus may not be reconstructable or may place the humeral head at excessive risk of avascular necrosis. Stemmed prosthetic replacement is often performed for such indications. This is a technically challenging procedure for which results are related to the healing of the bony tuberosities which in turn provides best rotator cuff function. Tuberosity healing is though to be related to good surgical technique. This article aims to review the history, indications, technique and results of prosthetic hemiarthroplasty of the shoulder. Where available, comparison of results is made with alternative prosthesis designs and with other available forms of glenohumeral arthroplasty for each indication.

Stemmed versus stemless total shoulder arthroplasty: a preliminary report and short-term results

Although several studies have been performed on the use of various devices in total shoulder arthroplasty (TSA), no data are available in order to establish whether to prefer stemmed or stemless humeral components. Thus, the purpose of our study was to evaluate the short-term functional outcome in a cohort of subjects treated with TSA randomized to treatment with stemmed or stemless prosthesis. In this prospective longitudinal study, we randomized to treatment with stemmed (group 1) or with stemless (group 2) humeral component in nineteen subjects (2 M and 17 F) diagnosed with humeral primary osteoarthritis with indication to TSA. We evaluated the range of movement of all the participants and the functional outcome using Constant score and simple shoulder test (SST) before and after 2 years from surgery. No differences were detected after 2 years from surgery in the two groups in terms of functional scores and range of motion (p > 0.05). Stemmed and stemless prostheses are comparable in terms of functional outcome. These data might be useful for the surgeon in order to choose more tissues-paring methodologies and less invasive procedures, such as stemless humeral implants.