Die metaphysär verankerte Prothese bei posttraumatischer und primärer Omarthrose: Kurzfristige Ergebnisse

Clinical and radiological outcomes of a stemless reverse shoulder implant: a two-year follow-up in 56 patients

Background

Since the introduction of stemless anatomic shoulder arthroplasty, many studies have been published on anatomic implants. For reverse stemless implants, however, there are only a few clinical follow-up studies available. The current clinical case series aims to present clinical and radiological outcomes of a new stemless reverse prosthesis system (Lima Shoulder Modular Replacement stemless).

Methods

We prospectively evaluated the outcome of 56 stemless total shoulder arthroplasties in 56 patients with a mean age of 61.2 years (46-76 years) at the time of implantation at a minimum follow-up of 24 months (range 24-41 months). All patients were physically and radiologically examined. Clinical outcomes were evaluated by using the Constant-Murley Score and the Subjective Shoulder Value.

Results

The mean Subjective Shoulder Value was 84.27% at the latest follow-up. Significant improvements from preoperative to latest follow-up were documented for Constant-Murley Score (34.9 pts to 74.43 pts, P < .001) and active range of motion (abduction 72° to 130°, flexion 36° to 138°, and external rotation 16°to 28°). There was one complete loosening of the humeral component without reoperation. Radiolucency lines were observed in anteroposterior or axial radiographs at the humeral component in 23% of the cases, most of them in anteroposterior view at the calcar region. Radiolucency line findings did not affect clinical outcomes. Major complications or revisions did not occur so far.

Conclusion

At short-term follow-up, stemless reverse shoulder systems show comparable clinical and radiological outcomes compared to stemmed reverse implants in the literature.

Clinical and radiologic results after anatomic stemless shoulder prosthesis: a minimum 4-year follow-up

BACKGROUND

Since the introduction of stemless anatomic shoulder arthroplasty, few midterm functional and radiographic results have been published. This article presents results of the Arthrex Eclipse prosthesis with a mean follow-up of 70 months.

METHODS

We prospectively evaluated the outcome of 53 arthroplasties in 51 patients with a mean age of 65 years at the time of implantation with a minimum follow-up of 48 months. All patients were physically and radiologically examined, and the results documented by Constant-Murley and Disabilities of the Arm, Shoulder, and Hand (DASH) scores.

RESULTS

Significant improvements from preoperative to last follow-up were documented in the Constant-Murley score (53.8%-83.5%, P < .001) and active range of motion (abduction 84°-108°, flexion 98°-125°, and external rotation 19°-41°). There was no significant difference between total and hemiarthroplasty. The mean DASH score was 28.3 points (95% confidence interval 20.1-35.2). Lowering of bone mineral density was observed in anteroposterior radiographs at the humeral component in 24.5% and at the glenoid component in 33.3%. The rate of complications was 15.7%.

CONCLUSION

This study finds improvements in functional, radiographic, and subjective midterm results comparable to other accessible data for stemless and stemmed arthroplasty.

Mid-term results of a stemless ceramic on polyethylene shoulder prosthesis - A prospective multicentre study

INTRODUCTION

Early reports of stemless shoulder arthroplasty have shown promising clinical and radiological outcomes. The purpose of this study was to report on the mid-term results of an implant that utilises a ceramic humeral head.

METHODS

A prospective, consecutive, multicentre study of stemless shoulder prosthesis with a minimum of four years of follow-up was conducted between August 2009 and May 2012. The adjusted Constant-Murley Score (CMS), revision rate and presence of radiolucent lines were recorded at intervals.

RESULTS

A total of 207 patients were eligible for study inclusion; 62.8% were female and mean age was 64.8 years (range 30-86). Mean follow-up was 70.7 months (range 48-100), 73% underwent TSA and 27% hemiarthroplasty. The mean CMS improvement was 42.6 (p < 0.0001) at 48 months. Radiolucencies were present in 2.7% of humeral zones and 14% of glenoid zones at 48-month follow-up. The revision rate was 6.3% with rotator cuff failure (2.9%) the most common indication.

CONCLUSIONS

Mid-term results demonstrate that the studied stemless implant with a ceramic humeral head had clinical and radiological outcomes that are comparable to other reported studies.

Stemless Total Shoulder Arthroplasty With Orthobiologic Augmentation

Total shoulder arthroplasty (TSA) has evolved over the years and is used for a variety of indications, with arthritis being the most common. Stemless TSA is a unique bone-preserving design that can eliminate rotational malalignment. Additionally, recent literature has found utility in the use of biological mesh and a platelet-rich plasma injection to improve healing. The purpose of this article is to outline the process of TSA using a stemless system and how to incorporate the use of amnion matrix and platelet-rich plasma into the surgical technique.

Revision of a Stemless Anatomic Implant into a Stemless Reverse Implant

INTRODUCTION

Stemless anatomic implants are the growing standard for solving osteoarthritis of the shoulder. If there are secondary rotator cuff insufficiency and the need to revise the implant into a reverse total shoulder, there is usually the option to revise it into a stemmed implant with losing the benefits of stemless implants. There are only a few stemless reverse implants available on the market. Usually, they are recommended as primary implants, but not for revision surgery. Case Report. A 61-year-old male with an indwelling anatomic stemless TESS (Total Evolutive Shoulder System, Zimmer Biomet, Warsaw, USA) implant presented in our clinic with growing pain and loss of range of motion. The TESS was implanted in 2007 as a hemishoulder arthroplasty. The X-ray was showing a stable implanted corolla with clearly growing protrusion of the glenoid. Because of the clinical presentation and the ultrasound investigation that showed only remnants of the supraspinatus and infraspinatus left, we decided that it is necessary to revise the stable implant in a reverse total shoulder arthroplasty. As the TESS was not designed to be convertible, it was clear that it has to be explanted. Due to the young age of the patient, we proposed an "off-label" change to a stemless reverse implant, e.g., the LIMA SMR stemless reverse prosthesis. A revision was possible without much bone loss, so the stemless reverse implant could be used. The clinical and radiological 2-year follow-up showed a good result.

CONCLUSION

Stemless implants are well known for anatomic implants, rarely for reverse implants, and seldom used for revision into reverse stemless. This case report shows that it is possible to revise a stemless anatomic implant with a stemless reverse, as long as the rules for implantation are applicable.

Prospective, Blinded, Randomized Controlled Trial of Stemless Versus Stemmed Humeral Components in Anatomic Total Shoulder Arthroplasty: Results at Short-Term Follow-up

BACKGROUND

Stemless humeral components for anatomic total shoulder arthroplasty (aTSA) have several reported potential benefits compared with stemmed implants. However, we are aware of no Level-I, randomized controlled trials (RCTs) that have compared stemless implants with stemmed implants in patients managed with aTSA. We sought to directly compare the short-term clinical and radiographic outcomes of stemless and stemmed implants to determine if the stemless implant is noninferior to the stemmed implant.

METHODS

We performed a prospective, multicenter, single-blinded RCT comparing stemless and short-stemmed implants in patients managed with aTSA. Range-of-motion measurements and American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation (SANE), and Constant scores were obtained at multiple time points. Device-related complications were recorded. Radiographic evaluation for evidence of loosening, fractures, dislocation, or other component complications was performed. Statistical analysis for noninferiority was performed at 2 years of follow-up for 3 primary end points: ASES score, absence of device-related complications, and radiographic signs of loosening. All other data were compared between cohorts at all time points as secondary measures.

RESULTS

Two hundred and sixty-five shoulders (including 176 shoulders in male patients and 89 shoulders in female patients) were randomized and received the allocated treatment. The mean age of the patients (and standard deviation) was 62.6 ± 9.3 years, and 99% of the shoulders had a primary diagnosis of osteoarthritis. At 2 years, the mean ASES score was 92.5 ± 14.9 for the stemless cohort and 92.2 ± 13.5 for the stemmed cohort (p value for noninferiority test, <0.0001), the proportion of shoulders without device-related complications was 92% (107 of 116) for the stemless cohort and 93% (114 of 123) for the stemmed cohort (p value for noninferiority test, 0.0063), and no shoulder in either cohort had radiographic signs of loosening. Range-of-motion measurements and ASES, SANE, and Constant scores did not differ significantly between cohorts at any time point within the 2-year follow-up.

CONCLUSIONS

At 2 years of follow-up, the safety and effectiveness of the stemless humeral implant were noninferior to those of the stemmed humeral implant in patients managed with aTSA for the treatment of osteoarthritis. These short-term results are promising given the potential benefits of stemless designs over traditional, stemmed humeral components.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Stemless Humeral Implants in Total Shoulder Arthroplasty

Through an iteration of various advancements, both short stem and stemless options for humeral fixation have been proposed and have shown clinical promise. The proposed benefits of a stemless humeral implant include greater bone preservation, less stress shielding, less risk of a diaphyseal stress riser, decreased surgical time, and less intraoperative blood loss. Potential downsides include the dependence on proximal bone quality for fixation, increased cost, the dependence on the strength of subscapularis fixation, and pending FDA approval for multiple implants. The purpose of this article is to review the evidence behind stemless implants including the biomechanical advantages and disadvantages, surgical technique, and clinical outcomes.

Stemless shoulder arthroplasty: review of short and medium-term results

Background

The number of anatomic total shoulder (TSA), hemiarthroplasty (HA), and reverse total shoulder arthroplasties (RTSA) is rapidly increasing in the United States. Stemless shoulder arthroplasty has numerous theoretical advantages, including preserved bone stock, decreased operating time, reduced rate of intraoperative humerus fracture, and flexibility of anatomic reconstruction. Only recently studies with more than 5 years of mean follow-up have become available.

Methods

The MEDLINE database was systematically queried to identify all studies reporting outcomes regarding anatomic or reverse stemless shoulder arthroplasty. Studies were categorized according to mean reported follow-up. Outcome scores and range of motion measurements were compiled. Complication and revision rates due to failure of the humeral or glenoid components were summarized.

Results

Nineteen TSA and HA studies with a total of 1115 patients were identified, with 4 studies and 162 patients with a mean follow-up between 60 and 120 months. Six RTSA studies with a total of 346 patients were identified, all with a mean follow-up between 18 and 60 months. There was a reliable improvement in outcomes compared with preoperative scores across studies. A cumulative 0.7% (8 of 1115) humeral component complication rate was found for TSA and HA components. There was a cumulative 1.7% (6 of 346) humeral complication rate for RTSA prostheses.

Conclusions

In the studies reporting similar outcome measures, there were reliable improvements on par with stemmed counterparts. Aggregate complication rates appear similar to those published in the literature for stemmed components. Evidence supporting the utility and safety of stemless designs would be strengthened by longer-term follow-up and additional prospective comparative studies.

Functional midterm follow-up comparison of stemless total shoulder prostheses versus conventional stemmed anatomic shoulder prostheses using a 3D-motion-analysis

Background

The aim of this study is to compare the functional midterm outcome of stemless shoulder prostheses with standard anatomical stemmed shoulder prostheses and to show that the STEMLESS results are comparable to the STEMMED with respect to active maximum range of shoulder motion (ROM) and Constant score (CS).

Methods

Seventeen patients underwent total shoulder arthroplasty (TSA) in 25 shoulder joints. Stemless TSA was performed in 12 shoulder joints (group STEMLESS), third-generation stemmed TSA in 13 shoulder joints (group STEMMED). Functional results were documented using the CS. 3D-motion-analysis using the Heidelberg upper extremity model (HUX) was conducted to measure active maximum (ROM).

Results

The group STEMLESS achieved a CS of 67.9 (SD 12.0) points and the group STEMMED of 70.2 (SD 5.8 points) without significant difference between the groups (p = 0.925). The maximum ROM of the group STEMLESS, ascertained by 3-D-motion-analysis, was in forward flexion 125.5° (SD 17.2°), in extension 49.4° (SD 13.8°), in abduction 126.2° (SD 28.5°) and in external rotation 40.3° (SD 13.9°). The maximum ROM of the group STEMMED, also ascertained by 3-D-motion analysis, was in forward flexion 135.0° (SD 16.8°), in extension 47.2° (SD 11.5°), in abduction 136.3° (SD 24.2°) and in external rotation 40.1° (SD 12.2°). The maximum ROM of the STEMLESS group was lower in forward flexion and abduction, higher in extension and almost identical in external rotation. But there was no significant difference (forward flexion p = 0.174, extension p = 0.470, abduction p = 0.345, external rotation p = 0.978).

Conclusion

Both types of shoulder prostheses achieve a similar and good active ROM and similar results in CS.

Trial registration

DRKS00013166, retrospectively registered, 11.10.2017

Nine-year outcome after anatomic stemless shoulder prosthesis: clinical and radiologic results

BACKGROUND

Several stemless shoulder implants are available on the market, but only a few studies have presented results with sufficient mid- to long-term follow-up. The present study evaluated clinical and radiologic outcomes 9 years after anatomic stemless shoulder replacement.

METHODS

This is a prospective cohort study evaluating the stemless shoulder prosthesis since 2005. Anatomic stemless shoulder replacement using a single prosthesis was performed in 49 shoulders; 17 underwent total shoulder replacement, and 32 underwent hemiarthroplasty. Forty-three patients were clinically and radiologically monitored after a mean of 9 years (range, 90-127 months; follow-up rate, 88%). The indications for shoulder replacement were primary osteoarthritis in 7 shoulders, post-traumatic in 24, instability in 7, cuff tear arthropathy in 2, postinfectious arthritis in 1, and revision arthroplasty in 2.

RESULTS

The Constant-Murley Score improved significantly from 52% to 79% (P < .0001). The active range of motion also increased significantly for flexion from 101° to 118° (P = .022), for abduction from 79° to 105° (P = .02), and for external rotation from 21° to 43° (P < .0001). Radiologic evaluation revealed incomplete radiolucency in 1 patient without clinical significance or further intervention. No revision caused by loosening or countersinking of the humeral implant was observed.

CONCLUSIONS

The 9-year outcome after stemless shoulder replacement is comparable to that of third- and fourth-generation standard shoulder arthroplasty.

Is the stemless humeral head replacement clinically and radiographically a secure equivalent to standard stem humeral head replacement in the long-term follow-up? A prospective randomized trial

BACKGROUND

Stemless humeral head replacement represents a young generation of shoulder arthroplasty. This study evaluated the differences of this new stemless design compared with the fourth-generation standard stemmed design.

METHODS

Total shoulder arthroplasty was performed in 20 patients with a stemless shoulder prosthesis (group 1) and in 20 patients with a standard stem humeral head replacement (group 2). Twenty-nine patients were examined clinically and radiographically at a minimum follow-up of 2 years and a minimum follow-up of 5 years. Functional results were assessed using the age- and gender-related Constant Score (CS). The radiographic analysis used native x-rays in 3 planes.

RESULTS

The postoperative CS improved significantly in both groups, with no significant difference between the minimum of 2-year and 5-year follow-up. The difference in the CS, its subcategories, and active range of motion between the implant groups was not significant. A significant difference was observed in the radiographic analysis for the zone adjacent to the humeral calcar, with a lower bone mineral density in 41% of group 2 and in 0% in group 1. Radiolucent lines were statistically more frequent in group 2. No statistical differences were observed between the implant groups for the change of the inclination angle, the medial offset, and the lateral offset.

CONCLUSION

Both implants showed consistently good functional and radiologic results without a significant difference and achieved an anatomic reconstruction of the humeral head geometry in the coronal plane.

Anatomic stemless shoulder arthroplasty and related outcomes: a systematic review

BACKGROUND

The 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.

METHODS

We 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.

RESULTS

We 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.

CONCLUSIONS

All 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.

Clinical and Radiographic Outcomes of the Simpliciti Canal-Sparing Shoulder Arthroplasty System: A Prospective Two-Year Multicenter Study

BACKGROUND

Stemmed humeral components have been used since the 1950s; canal-sparing (also known as stemless) humeral components became commercially available in Europe in 2004. The Simpliciti total shoulder system (Wright Medical, formerly Tornier) is a press-fit, porous-coated, canal-sparing humeral implant that relies on metaphyseal fixation only. This prospective, single-arm, multicenter study was performed to evaluate the two-year clinical and radiographic results of the Simpliciti prosthesis in the U.S.

METHODS

One hundred and fifty-seven patients with glenohumeral arthritis were enrolled at fourteen U.S. sites between July 2011 and November 2012 in a U.S. Food and Drug Administration (FDA) Investigational Device Exemption (IDE)-approved protocol. Their range of motion, strength, pain level, Constant score, Simple Shoulder Test (SST) score, and American Shoulder and Elbow Surgeons (ASES) score were compared between the preoperative and two-year postoperative evaluations. Statistical analyses were performed with the Student t test with 95% confidence intervals. Radiographic evaluation was performed at two weeks and one and two years postoperatively.

RESULTS

One hundred and forty-nine of the 157 patients were followed for a minimum of two years. The mean age and sex-adjusted Constant, SST, and ASES scores improved from 56% preoperatively to 104% at two years (p < 0.0001), from 4 points preoperatively to 11 points at two years (p < 0.0001), and from 38 points preoperatively to 92 points at two years (p < 0.0001), respectively. The mean forward elevation improved from 103° ± 27° to 147° ± 24° (p < 0.0001) and the mean external rotation, from 31° ± 20° to 56° ± 15° (p < 0.0001). The mean strength in elevation, as recorded with a dynamometer, improved from 12.5 to 15.7 lb (5.7 to 7.1 kg) (p < 0.0001), and the mean pain level, as measured with a visual analog scale, decreased from 5.9 to 0.5 (p < 0.0001). There were three postoperative complications that resulted in revision surgery: infection, glenoid component loosening, and failure of a subscapularis repair. There was no evidence of migration, subsidence, osteolysis, or loosening of the humeral components or surviving glenoid components.

CONCLUSIONS

The study demonstrated good results at a minimum of two years following use of the Simpliciti canal-sparing humeral component. Clinical results including the range of motion and the Constant, SST, and ASES scores improved significantly, and radiographic analysis showed no signs of loosening, osteolysis, or subsidence of the humeral components or surviving glenoid components.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Radiologic bone adaptations on a cementless short-stem shoulder prosthesis

BACKGROUND

This study evaluated the timing and location of radiologic bone adaptations related to shoulder arthroplasty using a single type of cementless short-stem shoulder prosthesis.

METHODS

Uncemented short-stem shoulder arthroplasties were evaluated in 52 patients at a mean age of 71.6 years (range, 58.1-86.6) with a minimum clinical and radiologic follow-up of 2 years (mean, 32 months; range, 23-52 months). All radiographs were analyzed for inclination of the stem, filling ratio of metaphysis and diaphysis, bone remodeling around the stem, radiolucent lines around the glenoid, and subsidence of the humeral stem. Finally, the radiographic and clinical findings were compared between patients with low and high bone adaptations.

RESULTS

At final follow-up, no loosening, subsidence, or osteolysis was seen. High bone adaptations were present in 27 patients (51.9%). Cortical thinning and osteopenia in the medial cortex (82.7%) and spot welds in the lateral cortex (78.6%) were the most frequently occurring bone adaptations. Patients with high bone adaptations had significantly higher metaphyseal (0.60 ± 0.05 vs. 0.56 ± 0.06; P = .024) and diaphyseal filling ratio (0.66 ± 0.04 vs. 0.61 ± 0.06; P = .019) at 2-year follow-up than patients with low bone adaptations. Clinical outcome was not influenced by the radiographic changes.

CONCLUSION

The clinical and radiologic results of the short-stem shoulder arthroplasty are comparable to those with the third and fourth generations of standard stem arthroplasty. Higher filling ratios in the metaphysis and the diaphysis were significantly associated with the occurrence of high bone adaptations.

Total shoulder arthroplasty: are the humeral components getting shorter?

Each generation of total shoulder arthroplasy has improved on the previous. The newest humeral component innovation is shortening the humeral component or eliminating the stem entirely to rely on stemless fixation in the humeral metaphysis. This offers theoretical advantages of preserved bone stock, less stress shielding, eliminating the diaphyseal stress riser, ease of stem removal at revision, and humeral head placement independent from the humeral shaft axis. There are a number of short term cohorts that have shown low complication rates and outcomes similar to previous generations of stemmed humeral components. Longer term and better designed studies are needed in order for short stems and stemless components to become the standard of care.

Midterm results of stemless shoulder arthroplasty: a prospective study

BACKGROUND

This study evaluated the functional and radiologic results of shoulder arthroplasty using a single type of stemless humeral head implant with a minimum follow-up of 5 years.

METHODS

Stemless shoulder arthroplasties in 78 patients at a mean age of 58 years were prospectively evaluated at a mean clinical and radiologic follow-up of 72 months. Functional results were documented using the age- and sex-adjusted Constant score with standardized radiographic examination.

RESULTS

The Constant score improved significantly from 38.1% to 75.3% (P < .0001). Active range of motion improved significantly for flexion (from 114° to 141°), abduction (from 74° to 130°), and external rotation (from 25° to 44°; P < .0001). Bone mineral density was reduced in 34.9% of the older population, without an influence on shoulder function (Constant score without lowering of bone density; 73%; Constant score with lowering of bone density 80%; P = .404). The overall complication rate was 12.8%, with an overall revision rate of 9%. None of the stemless implants were revised for loosening.

CONCLUSION

The functional and radiologic results of the stemless shoulder arthroplasty are comparable to the third and fourth generation of standard stem arthroplasty.

Stemless shoulder arthroplasty: current status

BACKGROUND

Since the original Neer humeral replacement in the 1950s, the standard primary anatomic total shoulder arthroplasty design has slowly evolved. Most recently, the humeral stem has become progressively shorter to help combat stem-related complications. Currently, there are several companies who have developed and marketed a stemless humeral arthroplasty component.

MATERIALS AND METHODS

Manufacturers' data for 5 stemless shoulder arthroplasty components currently on the market were analyzed and reviewed. A literature review of short-term results for stemless shoulder arthroplasty was completed.

RESULTS

Of the stemless shoulder arthroplasty systems available on the market, 3 are currently undergoing clinical trials in the United States. The Tornier Simpliciti (Tornier, Edina, MN, USA) clinical trial began in 2011. The study with 2-year minimum follow-up results is scheduled for completion in November 2014. The Arthrex Eclipse (Arthrex, Naples, FL, USA) clinical trial was started in January 2013. The tentative study completion date is 2017. The Biomet Nano (Biomet, Warsaw, IN, USA) clinical trial began in October 2013 and also has a tentative completion date of 2017. No other clinical trial is currently under way in the United States. Early results for stemless shoulder arthroplasty indicate clinical results similar to standard stemmed shoulder arthroplasty. Radiographic analysis indicates implant stability without migration or subsidence at 2- to 3-year minimum follow-up..

CONCLUSIONS

Several stemless shoulder arthroplasty implants are available outside the United States. Early clinical and radiographic results are promising, but well-designed clinical studies and midterm results are lacking. Three clinical trials are currently under way in the United States with initial availability for use anticipated in 2015.

[Options and limits of stemless shoulder prostheses]

Currently there are five manufacturers offering stemless implants for shoulder joint replacement. A total number of almost 10,000 stemless implants have been used in shoulder arthroplasty since 2004. There are two different types of metaphyseal anchorage, one obtained by impaction of a fin system and in the other implant system cage screw fixation is used. Regarding revision surgery the different types of implants show varying advantages and disadvantages in terms of secondary approach to the glenoid and the metaphyseal component. Because of the small number of cases and short period of observation at the present time none of the implant systems show a decisive superiority. In sclerotic bone the cage screw system seems to be advantageous whereas impaction using the fin system seems to be preferable in osteoporotic bone and conditions with defects of the bone. A prerequisite for all types of stemless shoulder implants is good quality bone. There should not be bony defects under the surface of the area of head resection. Stemless implants are not indicated for acute fractures.