Introduction. Total Elbow Arthroplasty (TEA) is recognized as an effective treatment solution for patients with rheumatoid arthritis or for traumatic conditions. Current total elbow devices can be divided into linked or unlinked design. The first design usually presents a linking element (i.e. an axle) to link together the ulnar and humeral components to stabilize the joint; the second one does not present any linkage and the stability is provided by both intrinsic design constraints and the soft tissues. Convertible modular solutions allow for an intraoperative decision to link or unlink the prosthesis; the modular connections introduce however additional risks in terms of both mechanical strength and potential fatigue and fretting phenomena that may arise not only due to low demand activities loads, but also high demand (HD) ones that could be even more detrimental. The aim of this study was to assess the strength of the modular connection between the axle and the ulnar component in a novel convertible elbow prosthesis design under simulated HD and activities of daily living (ADLs) loading. Methods. A novel convertible total elbow prosthesis (LimaCorporate, IT) comprising both ulnar and humeral components that can be linked together by means of an axle, was used. Both typical ADLs and HD torques to be applied to the axle were determined based on finite element analysis (FEA); the boundary load conditions for the FEA were determined based on kinematics analysis on real patients in previous studies. The FEA resultant moment acting on the axle junction during typical ADLs (i.e. feeding with 7.2lbs weight in hand) was 3.2Nm while for HD loads (i.e. sit to stand) was 5.7 Nm. In the experimental setup, 5 axle specimens coupled with 5 ulnar bodies through a tapered connection (5 Nm assembly torque) were fixed to a torque actuator (MTS Bionix) and submerged in a saline solution (9g/l). A moment of 3.2 Nm was applied to the axle for 5M cycles through a fixture to test it under ADLs loading. After 5M cycles, the axles were analyzed with regards to fretting behavior and then re-assembled to test them against HD loading by applying 5.7 Nm for 200K cycles (corresponding to 20 years function). Results. All 5 samples withstood all 5.2M loading cycles without any mechanical failure. At the end of 5M cycles, each axle was still stable as the measured disassembly torque was 3.96 +/−0.18 Nm. Slight signs of fretting were detected on the tapered connection after 5M cycles, however they did not compromise the mechanical connection nor the stability. Discussion and Conclusions. Currently there are no reference standards that properly define protocols for biomechanical testing of elbow prostheses. In the present study, a test to mechanically assess the strength of an axle connection under both typical ADLs and HD loads was set. The connection was able to withstand the imposed conditions. In general, testing of TEA devices should include not only standard ADLs loads but also HD loads, which could be more detrimental for the long-term survivorship. For any figures or tables, please contact authors directly

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

Aims. The reasons for failure of a hemirthroplasty (HA) when used to treat a proximal humeral fracture include displaced or necrotic tuberosities, insufficient metaphyseal bone-stock, and rotator cuff tears. Reverse total shoulder arthroplasty (rTSA) is often the only remaining form of treatment in these patients. The aim of this study was to evaluate the clinical outcome after conversions from a failed HA to rTSA. Material and Methods. A total of 35 patients, in whom a HA, as treatment for a fracture of the proximal humerus, had failed, underwent conversion to a rTSA. A total of 28 were available for follow-up at a mean of 61 months (37 to 91), having been initially reviewed at a mean of 20 months (12 to 36) postoperatively. Having a convertible design, the humeral stem could be preserved in nine patients. The stem was removed in the other 19 patients and a conventional rTSA was implanted. At final follow-up, patients were assessed using the American Shoulder and Elbow Surgeons (ASES) score, the Constant Score, and plain radiographs. Results. At final follow-up, the mean ASES was 59 (25 to 97) and the mean adjusted Constant Score was 63% (23% to 109%). Both improved significantly (p < 0.001). The mean forward flexion was 104° (50° to 155°) and mean abduction was 98° (60° to 140°). Nine patients (32%) had a complication; two had an infection and instability, respectively; three had a scapular fracture; and one patient each had delayed wound healing and symptomatic loosening. If implants could be converted to a rTSA without removal of the stem, the operating time was shorter (82 minutes versus 102 minutes; p = 0.018). Conclusion. After failure of a HA in the treatment of a proximal humeral fracture, conversion to a rTSA may achieve pain relief and improved shoulder function. The complication rate is considerable. Cite this article: Bone Joint J 2018;100-B:761–6

Modern total shoulder arthroplasty seeks to produce a construct that reproduces the kinematics and stability of the native glenohumeral joint. The latest 4th generation implants are modular, adaptable, and capable of use as either anatomic or reverse shoulder arthroplasty components. During surgery, these implants are “universal”; post-operatively, they are “convertible”. Recent work has demonstrated that reverse shoulder arthroplasty components may indeed be the emerging standard of care for most (if not all) shoulder arthroplasty indications. As this new frontier develops, the use of a convertible/universal implant creates the flexibility to individually choose the best surgical option for each patient

Arthroplasty implant modularity enables the surgeon to adapt the joint replacement construct to the patient's requirements, and often facilitates revision procedures. Total shoulder arthroplasty humeral modularity exists for many implant systems. Glenoid modularity with convertibility between anatomic and reverse shoulder arthroplasty is a recent development. Glenoid modularity is very useful when reconstructing glenoid bone deficiencies, or in providing a method for reverse shoulder arthroplasty joint lateralization. The live surgery will demonstrate a bio-reverse total shoulder arthroplasty (bRTSA). The humeral component is a modular press fit stem that can accommodate either reverse or anatomic metaphyseal components. The metaphyseal components can be exchanged without removing the stem or changing the humeral height. The glenoid base has three components. The trabecular titanium peg is available in two diameters, and four lengths for each diameter. The peg is fixed to a metal base plate via Morse taper. In revision settings, these components can be easily dissociated in situ, and a coring drill inserted over a well-fixed peg allows removal with minimal bone loss. Either a polyethylene component, or glenosphere can be attached to the baseplate to complete the glenoid construct. An innovative set of instruments have been developed to reliably prepare the glenoid and humeral bone graft. While the live surgery will demonstrate the grafting technique in a bRTSA, it can also be used to reconstruct glenoid deficiencies (eg, Walch B2). Implants have been developed to solve these issues, but often do so at the expense of very limited glenoid bone stock. Bone grafting actually creates a net increase in glenoid bone stock that may improve implant durability, and decrease revision complexity. The technique is quite simple and adds approximately ten minutes to operative time. I have used this technique for 5 years with no cases of graft failure

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

Experience has demonstrated in the hip and knee, related to total joint replacement arthroplasty, polymethyl methacrylate cement fixation can provide problems in terms of loosening, fragmentation, particulate wear and ultimate failure. These same problems have been recognised in total shoulder arthroplasty related to cement fixation of the glenoid. While cement fixation of the humeral component has proven much less problematic, there has been a swelling towards avoidance of using cement to secure the humeral component for fear of difficulty if revision is required. Surprisingly, with the high incidence of lucent lines, bone resorption and frank loosening, representing the most common source of failure in total shoulder arthroplasty, cementless fixation of the glenoid has not been, until now, embraced. The advent of reverse total shoulder arthroplasty has demonstrated the ability for secure cementless fixation to provide long-lasting secure implant retention in implants which have inherently higher shear and stress forces passing through the implant/bone interface. In anatomic total shoulder arthroplasty a woven tantalum anchor (Trabecular Metal) has proven to demonstrate secure cementless fixation as well. This presentation will discuss the use of trabecular metal anchored glenoid implants with and without additional screw fixation for anatomic and convertible reverse arthroplasty baseplates. Avoidance of complications with successful long-lasting outcomes requires meticulous surgical attention to detail

The results of revision TSA do not historically match the results of primary TSA. This is especially true if the diagnosis is a soft tissue related problem that leads to the revision. When a revision TSA is considered in this setting, instability is the major problem to overcome and a reverse TSA is most often needed. In the past this would require that the glenoid and humeral components be removed. Some manufacturers have produced shoulder prosthetic systems that can be converted to a reverse TSA without removing the humeral stem making the revision surgery potentially easier for both the patient and the surgeon.

The data bank from two academic shoulder services were utilised to compare outcomes of revision TSA with and without removing the humeral stem at the time of revision surgery. Sixty-seven patients were identified in which 22 did not have the stem removed and 45 required the stem to be revised. The pre-operative and post-operative data for 1 and 2 years were available. Codman's scores, range of motion, estimated blood loss, time in the operating room, complications and cost of the implants were evaluated.

The average blood loss was 280 cc vs. 500 cc, 145 minutes vs. 211 minutes, constant scores were 32 pre-op and 75 post-op vs. 32 pre-op and 70 post-op, complications 0 vs. 9 and the cost of the implants were 23% more in the stem removal group.

The results of revision TSA do not match the results of primary arthroplasty. The results of not having to remove the humeral stem when doing a revision arthroplasty vs. using a system that has to remove both components has certain advantages. The overall outcome score are similar, however, the complication rate, blood loss, time in the operating room and cost of the implants are significantly less.

Aims

Revision total elbow arthroplasty (TEA) is often challenging. The aim of this study was to report on the clinical and radiological results of revision arthroplasty of the elbow with the Latitude TEA.

As adverse events related to metal on metal hip arthroplasty have been better understood, there has been increased interest in toxicity related to the high circulating levels of cobalt ions. However, distinguishing true toxicity from benign elevations in cobalt levels can be challenging. The purpose of this review is to examine the use of cobalt alloys in total hip arthroplasty, to review the methods of measuring circulating cobalt levels, to define a level of cobalt which is considered pathological and to review the pathophysiology, risk factors and treatment of cobalt toxicity. To the best of our knowledge, there are 18 published cases where cobalt metal ion toxicity has been attributed to the use of cobalt-chromium alloys in hip arthroplasty. Of these cases, the great majority reported systemic toxic reactions at serum cobalt levels more than 100 μg/L. This review highlights some of the clinical features of cobalt toxicity, with the goal that early awareness may decrease the risk factors for the development of cobalt toxicity and/or reduce its severity.

Take home message: Severe adverse events can arise from the release of cobalt from metal-on-metal arthroplasties, and as such, orthopaedic surgeons should not only be aware of the presenting problems, but also have the knowledge to treat appropriately.

Cite this article: Bone Joint J 2016;98-B:14–20.

If a modular convertible total shoulder system is used as a primary implant for an anatomical total shoulder arthroplasty, failure of the prosthesis or the rotator cuff can be addressed by converting it to a reverse shoulder arthroplasty (RSA), with retention of the humeral stem and glenoid baseplate. This has the potential to reduce morbidity and improve the results. . In a retrospective study of 14 patients (15 shoulders) with a mean age of 70 years (47 to 83) we reviewed the clinical and radiological outcome of converting an anatomical shoulder arthroplasty (ASA) to a RSA using a convertible prosthetic system (SMR system, Lima, San Daniele, Italy). . The mean operating time was 64 minutes (45 to 75). All humeral stems and glenoid baseplates were found to be well-fixed and could be retained. There were no intra-operative or early post-operative complications and no post-operative infection. The mean follow-up was 43 months (21 to 83), by which time the mean visual analogue scale for pain had decreased from 8 pre-operatively to 1, the mean American Shoulder and Elbow Surgeons Score from 12 to 76, the mean Oxford shoulder score from 3 to 39, the mean Western Ontario Osteoarthritis of the Shoulder Score from 1618 to 418 and the mean Subjective shoulder value from 15 to 61. On radiological review, one patient had a lucency around the humeral stem, two had stress shielding. There were no fatigue fractures of the acromion but four cases of grade 1 scapular notching. . The use of a convertible prosthetic system to revise a failed ASA reduces morbidity and minimises the rate of complications. The mid-term clinical and radiological results of this technique are promising. Cite this article: Bone Joint J 2015;97-B:1662–7

Revision shoulder arthroplasty for failure secondary to soft tissue problems has improved with the availability of the reverse total shoulder system. The initial concept of a platform (convertible) stem was introduced in 2006. Removal of a well-fixed humeral stem can be a significant challenge and may require the surgeon to use osteotomy windows to successfully remove the implant. The increased time in the operating room, potential for complications and the cost of replacing the humeral component are all factors that make platform stem use a important consideration. The first report on total shoulder arthroplasty revision utilizing the platform stem concept confirmed improvements in patient morbidity and decreased costs. However, the overall functional improvement did not reveal a statistically significant improvement in pain relief or range of motion compared to those patients that had the humeral stem revised. Almost all major companies have adopted this concept of a convertible stem system for shoulder arthroplasty

Unlinked, linked and convertible total elbow arthroplasties (TEAs) are currently available. This study is the first to report the clinical results of the convertible Latitude TEA. This was a retrospective study of a consecutive cohort of 63 patients (69 primary TEAs) with a mean age of 60 years (23 to 87). Between 2006 and 2008 a total of 19 men and 50 women underwent surgery. The mean follow-up was 43 months (8 to 84). The range of movement, function and pain all improved six months post-operatively and either continued to improve slightly or reached a plateau thereafter. The complication rate is similar to that reported for other TEA systems. No loosening was seen. Remarkable is the disengagement of the radial head component in 13 TEAs (31%) with a radial head component implanted. Implantation of both the linked and the unlinked versions of the Latitude TEA results in improvement of function and decreased pain, and shows high patient satisfaction at mid-term follow-up. Cite this article: Bone Joint J 2015; 97-B:681–8

Between September 1993 and September 1996, we performed 34 Kudo 5 total elbow replacements in 31 rheumatoid patients. All 22 surviving patients were reviewed at a mean of 11.9 years (10 to 14). Their mean age was 56 years (37 to 78) at the time of operation. All had Larsen grade IV or V rheumatoid changes on X-ray. Nine (three bilateral replacements and six unilateral) had died from unrelated causes. One who had died before ten years underwent revision for dislocation.

Of the 22 total elbow replacements reviewed six had required revision, four for aseptic loosening (one humeral and three ulnar) and two for infection. Post-operatively, one patient had neuropraxia of the ulnar nerve and one of the radial nerve. Two patients had valgus tilting of the ulnar component.

With revision as the endpoint, the mean survival time for the prosthesis was 11.3 years (95% confidence interval (10 to 13) and the estimated survival of the prosthesis at 12 years according to Kaplan-Meier survival analysis was 74% (95% confidence interval 0.53 to 0.91).

Of the 16 surviving implants, ten were free from pain, four had mild pain and two moderate. The mean arc of flexion/extension of the elbow was 106° (65° to 130°) with pronation/supination of 90° (30° to 150°) with the joint at 90° of flexion. The mean Mayo elbow performance score was 82 (60 to 100) with five excellent, ten good and one fair result.

Good long-term results can be expected using the Kudo 5 total elbow replacement in patients with rheumatoid disease, with a low incidence of loosening of the components.