Background. Stemless prostheses are recognized to be an effective solution for anatomic total shoulder arthroplasty (TSA) while providing bone preservation and shortest operating time. Reverse shoulder arthroplasty (RSA) with stemless has not showed the same effectiveness, as clinical and biomechanical performances strongly depend on the design. The main concern is related to stability and bone response due to the changed biomechanical conditions; few studies have analyzed these effects in anatomic designs through Finite Element Analysis (FEA), however there is currently no study analyzing the reverse configuration. Additionally, most of the studies do not consider the effect of changing the neck-shaft angle (NSA) resection of the humerus nor the proper assignment of spatial bone properties to the bone models used in the simulations. The aim of this FEA study is to analyze bone response and primary stability of the SMR Stemless prosthesis in reverse with two different NSA cuts and two different reverse angled liners, in bone models with properties assigned using a quantitative computed tomography (QCT) methodology. Methods. Sixteen fresh-frozen cadaveric humeri were modelled using the QCT-based finite element methodology. The humeri were CT-scanned with a hydroxyapatite phantom to allow spatial bone properties assignment [Fig. 1]. Two implanted SMR stemless reverse configurations were considered for each humerus: a 150°-NSA cut with a 0° liner and a 135°-NSA cut with a 7° sloped liner [Fig. 2]. A 105° abduction loading condition was simulated on both the implanted reverse models and the intact (anatomic) humerus; load components were derived from previous dynamic biomechanical simulations on RSA implants for the implanted stemless models and from the OrthoLoad database for the intact humeri. The postoperative bone volume expected to resorb or remodel [Fig. 3a] in the implanted humeri were compared with their intact models in sixteen metaphyseal regions of interest (four 5-mm thick layers parallel to the resection and four anatomical quadrants) by means of a three-way repeated measures ANOVA followed by post hoc tests with Bonferroni correction. In order to evaluate primary stability, micromotions at the bone-Trabecular Titanium interface [Fig. 3b] were compared between the two configurations using a Wilcoxon matched-pairs signed-rank test. The significance level α was set to 0.05. Results. With the exception of the most proximal layer (0.0 – 5.0 mm), the 150°-NSA configuration showed overall a statistically significant lower bone volume expected to resorb (p = 0.011). In terms of bone remodelling, the 150°-NSA configuration had again a better response, but fewer statistically significant differences were found. Regarding micromotions, there was a median decrease (Mdn = 3.2 μm) for the 135°-NSA configuration (Mdn = 40.3 μm) with respect to the 150°-NSA configuration (Mdn = 43.5 μm) but this difference was non-significant (p = 0.464). Conclusions. For the analyzed SMR Stemless configurations, these results suggest a reduction in the risk of bone resorption when a 0° liner is implanted with the humerus cut at 150°. The used QCT-based methodology will allow further investigation, as this study was limited to one single design and load case. For any figures or tables, please contact the authors directly

The reverse total shoulder replacement (rTSR) has excellent clinical outcomes and prosthesis longevity, and thus, the indications have expanded to a younger age group. The use of a stemless humeral implant has been established in the anatomic TSR; and it is postulated to be safe to use in rTSR, whilst saving humeral bone stock for younger patients. The Lima stemless rTSR is a relatively new implant, with only one paper published on its outcomes. This is a single-surgeon retrospective matched case control study to assess short term outcomes of primary stemless Lima SMR rTSR with 3D planning and Image Derived Instrumentation (IDI), in comparison to a matched case group with a primary stemmed Lima SMR rTSR with 3D planning and IDI. Outcomes assessed: ROM, satisfaction score, PROMs, pain scores; and plain radiographs for loosening, loss of position, notching. Complications will be collated. Patients with at least 1 year of follow-up will be assessed. With comparing the early radiographic and clinical outcomes of the stemless rTSR to a similar patient the standard rTSR, we can assess emerging trends or complications of this new device. 41 pairs of stemless and standard rTSRs have been matched, with 1- and 2-year follow up data. Data is currently being collated. Our hypothesis is that there is no clinical or radiographical difference between the Lima stemless rTSR and the traditional Lima stemmed rTSR

The advent of modern anatomic shoulder arthroplasty occurred in the 1990's with the revelation that the humeral head dimensions had a fixed ratio between the head diameter and height. As surgeons moved from the concept of balancing soft tissue tension by using variable neck lengths for a given humeral head diameter, a flawed concept based on lower extremity reconstruction, improvements in range of motion and function were immediately observed. Long term outcome has validated this guiding principle for anatomic shoulder replacement with improved longevity of implants, improved patient and surgeon expectations and satisfaction with results. Once the ideal humeral head prosthesis is identified, and its position prepared, the surgeon must use a method to fix the position of the head that is correct in three dimensions and has the security to withstand patient activities and provide maximal longevity. Based again on lower extremity concepts, long stems were the standard of care, initially with cement, and now, almost universally without cement for a primary shoulder replacement. The incredibly low revision rates for humeral stem aseptic loosening shifted much of the attempted innovation to the challenges on the glenoid side of the reconstruction. However, glenoid problems including revision surgery, infections, periprosthetic fractures, and other complications often required the removal of the humeral stem. And, in many cases, the overall results of the procedure and the patient's long-term outcome was affected by the difficulty in removing the stem, leading surgeons to compromise the revision procedure, avoid revision surgery, or add to the overall morbidity with humeral fractures and substantial bone loss. With improved technology, including bone ingrowth methods, better matching of the proximal stem geometry to the humerus, and an understanding that the center of rotation (torque) on the humeral component is at the level of the humeral osteotomy, shorter stems and stemless humeral components were developed, now more than 10 years ago, primarily in Europe. With more than a decade of experience, our European colleagues have shown us that stemless humeral component replacement with a device that has both cortical and cancellous fixation is as effective as a stemmed device, easier to implant as well as revise when needed. The short-term results of the cancellous fixation stemless devices are acceptable, but longer follow-up is needed. Currently, the most widely used humeral components in the USA are short stem components, although the recent FDA approval of numerous stemless devices has initiated a shift from short stems to stemless devices. The truth is, short stem devices have a firm position in the USA surgeons' armamentarium today due to regulatory restrictions. A decade ago, without a predicate on the market, it was not conceivable that a stemless device that was already gaining popularity in Europe would be able to get 510K approval, and therefore would require a lengthy and expensive FDA IDE process. However, shorter stems had already been approved in the USA, as long as the stem length was 7 centimeters, matching the market predicate. Now, in 2018, based on evidence and outcomes, stemless humeral components should be the first choice when treating primary osteoarthritis of the glenohumeral joint. Short stem or longer stem devices should be reserved for those cases where stemless fixation is not possible, which is less than 10% of patients with primary OA of the shoulder

Abstract. Aim. Excessive glenoid retroversion and posterior wear leads to technical challenges when performing anatomic shoulder replacement. Various techniques have been described to correct glenoid version, including eccentric reaming, bone graft, posterior augmentation and custom prosthesis. Clinical outcomes and survivorship of a Stemless humeral component with cemented pegged polyethylene glenoid with eccentric reaming to partially correct retroversion are presented. Patients and Methods. Between 2010– 2019, 115 Mathys Affinis Stemless Shoulder Replacements were performed. 50 patients with significant posterior wear and retroversion (Walch type B1, B2, B3 and C) were identified. Measurement of Pre-operative glenoid retroversion and Glenoid component version on a post op axillary view was performed by method as described by Matsen FA. Relative correction was correlated with clinical and radiological outcome. Results. 4 were lost to follow up. 46 patients were therefore reviewed. The mean follow up was 4 years (2–8.9 years). Walch B1, Pre op Retroversion: 12 (8–20), post op retroversion :11.8 (−4 to 19), correction= 0.2. Walch B2, Pre op Retroversion :18.4 (10–32), post op retroversion: 13.2 (1 −22), correction= 5.2. Walch B3, Pre op Retroversion: 19.1 (13–32)post op retroversion : 16.1 (9–25), correction= 3.0. Walch C, Pre op Retroversion: 33.3 (28–42) post op retroversion: 16.0 (6–27), correction= 17.3. 3 patients required revision surgery for rotator cuff failure. Conclusion. Partial correction of glenoid retroversion with eccentric reaming and implantation of cemented pegged polyethylene component leads to satisfactory clinical outcomes at midterm follow up. No revisions for aseptic loosening of the glenoid were required

Introduction. The new era of shoulder arthroplasty is moving away from long stemmed, cemented humeral components to cementless, stemless and metaphyseal fixed implants and to humeral resurfacing. The early clinical results and functional outcome of stemless shoulder arthroplasty is presented. Methods. A retrospective single-surgeon series of stemless shoulder prostheses implanted from 2011 to 2013 at our institution was evaluated. Perioperative complications, Theatre time and length of hospital stay (LOS) were recorded. Postoperative radiographic and clinical evaluation including measurement of joint mobility, the Oxford Shoulder Score (OSS), and Disabilities of the Arm, Shoulder and Hand (DASH) score by independent evaluators were made. Results. A total of 23 stemless shoulder arthroplasty were implanted in 22 patients. Mean age was 57.8 years. Mean follow up was 22 months (8–45). Symptomatic primary gleno-humeral osteoarthritis was the main indication for implantation (83%). None of the patients experienced periprosthetic fractures, glenoid notching, and implant loosening/migration. Mean OSS (44 ± 6.0) and mean DASH score (11 ± 6.5). Mean operative time was (88 ± 16.0 min) and mean length of hospital stay (1.1 ± 0.82 day). Active shoulder motion improved by (mean): 30° (95% CI 10–45) external rotation, 67° (95% CI 30- 100) forward elevation and 54° (95% CI 35- 90) Abduction. Conclusion. The implantation of stemless shoulder prosthesis in our institution offered good clinical results manifested by improved range of motion and favourable patient reported outcome measures. Although long term follow up is warranted, early results appear promising in young patients with symptomatic gleno-humeral osteoarthritis

In the past century several shoulder reconstruction systems with different types of prostheses and fixation methods have been developed to improve shoulder arthroplasty, especially to cover a wide range of pathologies and revision situations. The aim of this prospective trial was to report clinical and radiological mid-term results of a stemless humeral head replacement with metaphyseal hollow screw fixation. A consecutive series of 147 shoulders in 138 patients (84 female, 54 male; mean age of 67 years, range 40–84) undergoing stemless humeral head arthroplasty were considered for this single-centre trial. We prospectively followed 120 shoulders (40 hemi- and 80 total-arthroplasties) for an average of five years or until a reoperation. Patient's clinical and functional outcome was evaluated according to the Constant score and active range of motions (ROM) was measured. Patient's satisfaction with the treatment was evaluated. Additionally, operating times and complications were recorded. Radiological assessment for radiolucencies or implant migration was performed. The mean Constant score significantly increased from 35 points preoperatively to 62 points at the last follow-up (p<0.001). All subcomponents (pain, daily activity, ROM, strength) of the Constant score were significantly (p<0.001) higher at follow-up. Active flexion improved from 90° to 150° (p<0.001), active abduction from 78° to 120° (p<0.001), and active external rotation from 20° to 40° (p<0.001) between preoperative and last clinical assessment. Furthermore, 54% of the patients were very satisfied, 34% satisfied, and 12% unsatisfied. Operating times of the new stemless prosthesis were significantly shorter compared to a stemmed prosthesis. Over the follow-up period, all humeral head components were radiological centred, changing radiolucencies were detected; however no implant loosening occurred. Revision surgery for implant loosening only occurred in the metal-backed glenoid component with hollow screw fixation; otherwise no complication due to implant loosening was detected. The promising five-year results suggest that the concept of this stemless humeral head replacement might be an expedient alternative to existing shoulder replacements. Anatomical cutting of the humeral head and hollow screw fixation allow a familiar access to the glenoid combined with a shaft independent, less complex bone-sparing surgery along with shorter operating times and favourable revision situation

Stemless shoulder arthroplasty implants for the proximal humerus provide cementless metaphyseal prosthetic fixation. A near-perfect anatomic restoration of the proximal humeral articular surface is possible with this canal-sparing design—avoiding the risks associated with humeral stems and preserving bone for later revision. When compared with proximal humeral resurfacing, stemless arthroplasty avoids the potential technical errors that may lead to oversized implants, abnormal shift of the glenohumeral joint center of rotation, and excessive strain on the native rotator cuff. While canal-sparing stemless implants represent a new concept in shoulder arthroplasty without mid- and long-term results, the failures associated with resurfacing humeral arthroplasty have been documented in the literature. Unlike a stemless component, use of a resurfacing technique (and hence preservation of the humeral head) makes glenoid prosthetic implantation challenging and often impossible

Humeral component failure in total shoulder arthroplasty has been rare with contemporary design systems. Are stemless implant designs superior to contemporary short-stem humeral component technologies? This presentation will provide information to address this question. Stemless technology became available in Europe and other parts of the world in 2004 and 2005 compared to only recently in the United States of America. Short-stem designs have developed with third generation implant systems. Advantages of short-stem implant designs include the following: the humeral canal facilitates proper head component position; modularity between the stem and head allows for modifications of version, inclination and offset to match the native anatomy and these designs are convertible for easier revision. This debate will demonstrate that short-stem implant designs provide the surgeon with more versatility to provide our patients with the best outcomes

The modern humeral head resurfacing was developed by Stephen Copeland, M.D. and introduced in 1986 as an alternative to stemmed humeral implants. At the time, first and second generation monoblock and modular stems with non-offset humeral heads posed many challenges to the surgeon to recreate the pre-morbid humeral head anatomy during anatomic TSA. The consequences of non-anatomic humeral head replacement were poor range of motion, increased native glenoid or glenoid component wear and premature rotator cuff failure. Additionally, the early generation humeral stems were very difficult to extract when revision was needed. The original stemless devices were cup resurfacing implants that were designed based on the early hip experience. The Copeland resurfacing device offered the ability to better match native humeral head anatomy and was considered less invasive and easier to revise. Glenoid exposure required more extensive dissection but TSA could be successfully completed. Clinical results for motion, function and outcome scores are similar to stemmed implants. The survivorship of the implants is also on par with other available implants and loosening has not been an issue. Stress shielding is not reported. Multiple manufacturers offered similar products all designed to try to predictably recreate the pre-morbid anatomy and to make insertion easier. Critical review of resurfacing arthroplasty radiographs has raised concern about the challenges of placing the implant with proper sizing and position. Most surgeons have implanted resurfacing implants as hemiarthroplasties. The development of anatomic TSA implants has allowed surgeons to better recreate the normal pre-morbid anatomy of the humerus. Newer stem designs are convertible or easily removable. This counters many of the original design benefits of resurfacing. The primary reason for revision of resurfacing implants is malposition followed by glenoid arthrosis and rotator cuff failure. Revision surgery after resurfacing has had mixed results. Stemless implants were introduced in Europe 13 years ago. Stemless devices share the benefits of resurfacing as minimally invasive and easier to revise. The added benefit of better glenoid access allows the surgeon to implant a glenoid. Most available implants have minimal follow-up. Mid-term follow-up of one design has demonstrated good fixation and loosening is uncommon. No studies are available that critically evaluate the surgeon's ability to recreate normal pre-morbid anatomy, whether revision arthroplasty is bone preserving and if results of revision will improve

Purpose. Traditional total knee arthoplasty techniques have involved implantation of diaphyseal stems to aid in fixation expecially when using constrained polyethylene inserts. While the debate over cemented vs uncemented stems continues, the actual use of stems is considered routine. The authors' experience with cemented stemmed knee revisions in older patients with osteoporotic bone has been favorable. Our younger patients with press-fit stems from varying manufacturers have been plagued with a relatively high incidence of component loosening and stem tip pain in the tibia and occasionally thigh. We report the early results of the first 20 total knee revisions using press-fit metaphyseal filling sleeved stemless implants with constrained bearings. Methods. Twenty three patients with failed primary or revision total knees were assigned to receive stemless sleeved revision knee designs using the DePuy MBT/TC3 system. Reasons for revision included loosening, implant fracture, stiffness, instability, and stem pain. Twenty patients (ages ranging from 42–73) were successfully reconstructed without stems. Six knees with significant uncontained cavitary defects were included. Three patients with unexpectedly osteoporotic metaphyseal bone were revised with cemented stemmed implants and excluded. All cases used cement for initial fixation on the cut bone surface and fully constrained mobile bearing inserts. Results. Follow up ranged from six months to three years. All patients had radiographic evidence of well fixed stable implants on most recent examination. All four cases of revision for “end of stem pain” had complete resolution of symptoms within two weeks of revision surgery. Long leg anterior posterior mechanical alignment x-rays measured within two degrees of neutral in all cases. Knee Society Scores improved an average of 34 points. Clinical results for revision for stiffness had the lowest final scores post operatively. Conclusion. Stemmed total knee arthroplasty revision implants with or without cement are considered the standard for most revision reconstructions. Recently, primary total hip replacements using newer short metaphyseal stems have shown promising early clinical results. This case series of twenty total knee revisions using stemless press-fit metaphyseal sleeves shows similarly favorable outcomes. The complications of stemmed implants such as stem tip pain and difficulty of cemented stem removal can be avoided successfully in non-osteporotic bone reconstructions. With stable bony ingrowth visible on early post-operatyive radiographs, long term stable fixation even with constrained bearings is expected. Longer follow up will be needed to validate this technique for routine use

Humeral implant design in shoulder arthroplasty has evolved over the years. The third generation shoulder prostheses have an anatomic humeral stem that replicates the 3-dimensional parameters of the proximal humerus. The overall complication rate has decreased as a result of these changes in implant design. In contrast, the rate of periprosthetic humeral fractures has increased. To avoid stem-related complications while retaining the advantages of the third generation of shoulder implants, the stemless total evolutive shoulder system has been developed. The indications, the surgical technique, and the complications of this humeral implant in shoulder arthroplasty will be described

We compared the rate of revision of two classes of primary anatomic shoulder arthroplasty, stemmed (aTSA) and stemless (sTSA) undertaken with cemented all polyethylene glenoid components. A large national arthroplasty registry identified two cohort groups for comparison, aTSA and sTSA between 1. st. January 2011 and 31. st. December 2020. A sub-analysis from 1 January 2017 captured additional patient demographics. The cumulative percentage revision (CPR) was determined using Kaplan-Meier estimates of survivorship and hazard ratios (HR) from Cox proportional hazard models adjusted for age and gender. Of the 7,533 aTSA procedures, the CPR at 8 years was 5.3% and for 2,567 sTSA procedures was 4.0%. There was no difference in the risk of revision between study groups (p=0.128). There was an increased risk of revision for aTSA and sTSA undertaken with humeral head sizes <44mm (p=0.006 and p=0.002 respectively). Low mean surgeon volume (MSV) (<10 cases per annum) was a revision risk for aTSA (p=0.033) but not sTSA (p=0.926). For primary diagnosis osteoarthritis since 2017, low MSV was associated with an increased revision risk for aTSA vs sTSA in the first year (p=0.048). Conversely, low MSV was associated with a decreased revision risk for sTSA in the first 6 months (p<0.001). Predominantly aTSA was revised for loosening (28.8%) and sTSA for instability/dislocation (40.6%). Revision risk of aTSA and sTSA was associated with humeral head size and mean surgeon volume but not patient characteristics. Inexperienced shoulder arthroplasty surgeons experience lower early revision rates with sTSA in the setting of osteoarthritis. Revision of aTSA and sTSA occurred for differing reasons

Introduction

Revision TKA can be a difficult and complex procedure. Bone quality is commonly compromised and stem fixation is required in many cases to provide stability of the prosthetic construct. However, utilization of diaphyseal engaging stems adds complexity to the case and can present technical challenges to the surgeon. Press fit metaphyseal sleeves can provide stable fixation of the construct without the need for stems and allows for biologic ingrowth of the prosthesis. Metaphyseal sleeves simplify the revision procedure by avoiding the need to prepare the diaphysis for stems, alleviating the need for offset stems and decreasing the risk of intra-operative complications. The ability to obtain biologic fixation in the young patient is also appealing. This study reports on the author's mid-term experience with this novel technique.

Humeral resurfacing arthroplasty has been advocated as an alternative to stemmed humeral component designs given its ability to preserve proximal bone stock. Further, these implants have become more attractive given the possibility of stem-related complications including humeral fracture, stress shielding, and osteolysis; complications that may necessitate fixation, revision to long stem components, or reverse total shoulder arthroplasty. As more total shoulder arthroplasties are performed in younger patient populations, the likelihood of increased revision procedures is inevitable. Maintaining proximal bone stock in these cases with use of a resurfacing arthroplasty not only facilitates explant during revision arthroplasty, but preservation of proximal metaphyseal bone facilitates reimplantation of components. Clinical results of these resurfacing components have demonstrated favorable results similar to stemmed designs. Unfortunately, resurfacing arthroplasty may not be as ideal as was hoped with regard to recreating native humeral anatomy. Further, resurfacing arthroplasty may increase the risk of peri-prosthetic humeral fracture, and lack of a formal humeral head cut makes glenoid exposure more difficult, which may be associated with a higher degree of neurovascular injury. Stemless humeral components are designed for strong metaphyseal fixation and avoid the difficulty with glenoid exposure seen in resurfacing designs, as these components require a formal humeral head cut. Early clinical outcomes of a single stemless design demonstrated significant improvements in clinical outcome scores, without evidence of component migration, subsidence or loosening. The only mid-term clinical results of stemless design implants are seen with the Arthrex Eclipse system (Arthrex, Naples, FL). In a prospective study involving 78 patients at 5-year follow-up, significant improvements were observed in clinical outcome scores. While there was evidence of proximal stress shielding in an older population, this did not influence shoulder function. The overall revision rate was 9% at 5 years, with no component necessitating revision as a result of humeral component loosening. Resurfacing arthroplasty and stemless humeral components in total shoulder arthroplasty remain attractive options to preserve proximal metaphyseal bone stock, avoiding stem-related complications. Early and mid-term clinical outcomes are comparable to stemmed designs and demonstrate no evidence of humeral component loosening

Durable humeral component fixation in shoulder arthroplasty is necessary to prevent painful aseptic loosening and resultant humeral bone loss. Causes of humeral component loosening include stem design and material, stem length and geometry, ingrowth vs. ongrowth surfaces, quality of bone available for fixation, glenoid polyethylene debris osteolysis, exclusion of articular particulate debris, joint stability, rotator cuff function, and patient activity levels. Fixation of the humeral component may be achieved by cement fixation either partial or complete and press-fit fixation. During the past two decades, uncemented humeral fixation has become more popular, especially with short stems and stemless press fit designs. Cemented humeral component fixation risks difficult and complicated revision surgery, stress shielding of the tuberosities and humeral shaft periprosthetic fractures at the junction of the stiff cemented stem and the remaining humeral shaft. Press fit fixation may minimise these cemented risks but has potential for stem loosening. A randomised clinical trial of 161 patients with cemented vs. press fit anatomic total shoulder replacements found that cemented fixation of the humeral component provided better quality of life, strength, and range of motion than uncemented fixation but longer operative times. Another study found increased humeral osteolysis (43%) associated with glenoid component loosening and polyethylene wear, while stress shielding was seen with well-fixed press fit humeral components. During reverse replacement the biomechanical forces are different on the humeral stem. Stem loosening during reverse replacement may have different factors than anatomic replacement. A systemic review of 41 reverse arthroplasty clinical studies compared the functional outcomes and complications of cemented and uncemented stems in approximately 1800 patients. There was no difference in the risk of stem loosening or revision between cemented and uncemented stems. Uncemented stems have at least equivalent clinical and radiographic outcomes compared with cemented stems during reverse shoulder arthroplasty. Durable humeral component fixation in shoulder arthroplasty is associated with fully cemented stems or well ingrown components that exclude potential synovial debris that may cause osteolysis

Introduction. The number of total hip arthroplasties in young patients is continuosly increasing. Nowdays, the study of the materials wear, with the goal of improving the survivorship of implants, represents a fundamental subject in this kind of surgery. The role of ceramic materials in the valutation of types of wear is particularly known. Materials and Methods. We have selected 834 patients, underwent total hip arthroplasty, in which a ceramic head was impalnted with a maximum follow up of ten years. 367 patients were males and 467 were females, operated by 14 surgeons of the same equipe of Orthopaedic and Traumatology Department. A postero-lateral approach, according to Gibson Moore, and an extrarotator tendons transosseal repair was performed. Results. 446 ceramic liners, 354 polyethylene liners and 34 metallic liners were used. 18 types of stems, 5 of which stemless, were implanted. The mean survivorship of all cohrt of patients was 92% at 10 years. No ceramic heads and liners breakage occurred. In particular, of 69 total hip arthroplasties, implanted in 2005, only 3 were revised. Discussion. In our cohort review no major failures of ceramic components were observed. These datas suggested the importance of design and up grading of new materials, in order to achieve better long term results. Therefore, the ceramic components represent the gold standard, specifically in young active patients with good long term results reguarding functional outcomes and wear of implants. Conclusions. The use of ceramic head, assembled with ceramic or polyethylene liners, also demonstrated good results at 10 years follow up. Ceramic-on- polyethylene is a valid alternative to ceramic-on-ceramic in consideration of the lower cost and theoretical lower risk of breakage

Background. Total Shoulder Arthroplasty (TSA) has been shown to improve the function and pain of patients with severe degeneration. Recently, TSA has been of interest for younger patients with higher post-operative expectations; however, they are treated using traditional surgical approaches and techniques, which, although amenable to the elderly population, may not achieve acceptable results with this new demographic. Specifically, to achieve sufficient visualization, traditional TSA uses the highly invasive deltopectoral approach that detaches the subscapularis, which can significantly limit post-operative healing and function. To address these concerns, we have developed a novel surgical approach, and guidance and instrumentation system (for short-stemmed/stemless TSA) that minimize muscle disruption and aim to optimize implantation accuracy. Development. Surgical Approach: A muscle splitting approach with a reduced incision size (∼6–8cm) was developed that markedly reduces muscle disruption, thus potentially improving healing and function. The split was placed between the infraspinatus and teres-minor (Fig.1) as this further reduces damage, provides an obvious dissection plane, and improves access to the retroverted articular surfaces. This approach, however, precludes the use of standard bone preparation methods/instruments that require clear visualization and en-face articular access. Therefore, a novel guidance technique and instrumentation paradigm was developed. Minimally Invasive Surgical Guidance: 3D printed Patient Specific Guides (PSGs) have been developed for TSA; however, these are designed for traditional, highly invasive approaches providing unobstructed access to each articular surface separately. As the proposed approach does not offer this access, a novel PSG with two opposing contoured surfaces has been developed that can be inserted between the humeral and scapular articular surfaces and use the rotator cuff's passive tension to self-locate (Fig.2). During computer-aided pre-operative planning/PSG design, the two bones are placed into an optimized relative pose and the PSG is constructed between and around them. This ensures that when the physical PSG is inserted intra-operatively, the bones are locked into the preoperatively planned pose. New Instrumentation Paradigm: With the constraints of this minimally invasive approach, a new paradigm for bone preparation/instrumentation was required which did not rely on en-face access. This new paradigm involves the ability to simultaneously create glenoid and humeral guide axes – the latter of which can guide humeral bone preparation and be a working channel for tools – by driving a short k-wire into the glenoid by passing through the humerus starting laterally (Fig.3). By preoperatively defining the pose produced by the inserted PSG as one that collinearly aligns the bones’ guide axes, the PSG and an attached c-arm drill guide facilitate this new lateral drilling technique. Subsequently, bone preparation is conducted using novel instruments (e.g. reamers and drills for creating holes radial to driver axis) powered using a trans-humeral driver and guided by the glenoid k-wire or humeral tunnel. Conclusion. To meet the expectations of increasingly younger TSA patients, advancements in procedural invasiveness and implantation accuracy are needed. This need was addressed by developing a novel, fully integrated surgical approach, PSG system, and instrumentation paradigm, the initial in-vitro results of which have demonstrated acceptable accuracy while significantly reducing invasiveness

Thrust plate prosthesis (TPP) is a bone conserving prosthesis in use for over thirty years. TPP is a stemless and uncemented femoral prosthesis fixed at the lateral femoral cortex with a bolt, plate and screw. This has a metal-on-metal articulation with a 28mm Metasul head and Allofit press fit acetabular cup. Our study aimed to assess the survival of this prosthesis. At Oswestry 234 TTP's were implanted between 1995 and 2005. All patients completed a self-assessed questionnaire of Harris Hip Score pre-operatively and post-operatively at 2 months, 1 year, and then yearly. Only those who had a follow up was within the last two years were included in the analysis. 76 patients who had failed to satisfy the criteria were excluded. Of the 158 hips in the study 75 hips were in male patients and 83 were in female patients. The median age of patients was 52 years (range 15 to 82). 75 hips were on the right side and 83 on the left. All patients were operated by the senior author or a senior trainee under his supervision (seven hips). Revision of the implant or decision to revise was taken as the end point of our study. The median time to follow up was 7 years (range 1 to 15). The median pre-operative hip score was 43 (range 3 to 77) which rose to 83 points (range 11 to 100) at the latest follow up. Median hip score in females improved from 39 to 82 points and in males from 52 to 85 points. Twelve patients (5.1%) underwent revision surgery either for infection or aseptic loosening. The Thrust Plate Prosthesis had a good outcome with an increase in hip score of 40 points and 94.9 % survival at a median of 7 years

Background. Partial humeral head resurfacing using a stemless implant is a bone-conserving option in treatment of focal chondral defects. We report our experience using the Arthrosurface HemiCAP® device. Methods. This is a retrospective study of patients with focal chondral defects of the humeral head, treated with partial resurfacing arthroplasty, with a minimum follow-up of 2 years. Mean patient age was 45.4 years (range 27–76). Patients were analyzed in 2 groups: those who underwent HemiCAP for an isolated humeral head defect, and those who had HemiCAP combined with biologic resurfacing of concomitant glenoid disease. Results. 39 patients met inclusion criteria, 5 of whom had concomitant biologic glenoid resurfacing. 24 of 34 shoulders (70.6%) with HemiCAP alone demonstrated functional improvement and decreased pain. Mean forward flexion showed some improvement from 131 degrees pre-operatively to 158 degrees post-operatively (p=0.004). Mean Subjective Shoulder Value improved from 35.0% to 83.6% (p< 0.001). ASES score improved from 29.8 to 77.7(p< 0.001). However, follow-up radiographs showed progression of glenoid disease in 20.6%(7 shoulders). 5 shoulders(14.7%) failed and were revised: 3 to total shoulder arthroplasty, 1 to hemiarthroplasty, and 1 patient underwent glenohumeral fusion. 5 (14.7%) had some pain at latest follow-up but were pursuing a course of conservative management. In the group with associated biologic glenoid resurfacing, all 5 patients had ongoing pain and progression of glenohumeral arthritis requiring revision or glenohumeral fusion. Conclusion. While 70% of patients with an isolated humeral head chondral defect had significant improvement in pain and function after HemiCAP, the outcomes were not superior to those published for complete humeral head resurfacing, or for stemmed prostheses. HemiCAP was not successful for patients with concomitant glenoid disease. Results for these patients were inferior to those published for total shoulder arthroplasty, and ultimately all were revised to a stemmed prosthesis or fused

Recent trends in surgical techniques for THR, i.e. MIS and anterior approaches, have spawned an interest in and possible need for shorter femoral prostheses. Although, early clinical investigations with custom short stems have reported very encouraging results, the transition to off-the-shelf (OTS) versions of shorter length prostheses has not met with the same degree of success. Early reports with OTS devices have documented unacceptably high and significant incidences of implant instability, migration, mechanical/aseptic failure, and technical difficulty in achieving reproducible implantation outcomes. They have highlighted the absolute need for a better understanding of the consequences of changes in implant design as well as for improvements in instrumentation and surgeon training. Two basic questions must be addressed. First, what is the purpose of a stem? And second, can stem length be reduced and if so by how much can this be safely done. What are the effects of stem shortening and are there other design criteria which must take on greater importance in the absence of a stem to protect against implant failure. To examine these questions a testing rig was constructed which attempts to simulate the in vivo loading situation of a hip, fig. 1. Fresh cadaveric femora were tested with the femora intact and then with femoral components of varying stem length implanted to examine the distribution of stresses within the femur under increasing loads as a function of stem length. Our studies indicated that a stem is not an absolute requirement in order to achieve a well functioning, stable implant. However in order to reduce the possibility of mechanical failure a reduced stem or stemless implant absolutely must have three important characteristics to its design. First, it must have sufficient medial/lateral dimension to provide stability against subsidence and varus stress; second it must have a flat posterior surface, parallel and in contact with the posterior endosteal surface of the proximal femur with which to maximize A/P stability against flexion/extension forces (As a consequence of this design feature, appropriate anteversion must be achieved in the neck region of the prosthesis and not by rotation of the implant within the proximal metaphyseal cavity of the femur); and third, the implant must also have a cross-sectional geometry that will stabilize against torsional loading about the long axis of the femur. Therefore, simply reducing the length of an existing implant to accommodate changes in surgical techniques may not be a reasonable or safe design change. Such shortened versions of existing stem designs must be rigorously tested before being released for general use. The required design parameters outlined above have been clinically validated in custom fabricated implants. They have been shown to reduce aseptic loosening and migration of a short stem femoral implant. This report will provide the clinical review of a multi-center experience with the first 200 off-the-shelf “Lateral Flare” short stem implants