Mr David Cloke, a Which Medical Device Specialist Editor (upper limb orthopaedics) is an Orthopaedic Surgeon at North Tyneside General Hospital, UK. Here, Mr Cloke examines several total elbow replacement designs.
Mr Cloke is a Sheffield Shoulder and Elbow Fellow, a member of the British Shoulder and Elbow Society & Faculty of Sports and Exercise Medicine. He is also a tutor in sports medicine at Bath University. His areas of interest include shoulder and elbow trauma, arthroscopy and joint replacement whilst Mr Cloke's research interests include shoulder and elbow surgery and football injuries.
Introduction
Total elbow replacement (TER) has been in the domain of upper limb surgeons for three decades. However, due to improved medical management of rheumatoid arthritis fewer arthroplasties are being performed overall (1). Nevertheless increasing numbers of procedures are being performed for trauma and its sequelae in the older population, especially females, due to evidence of acceptable outcomes (2,3). Whilst a recent registry analysis suggested a 90% 10 year overall survivorship for TER (1), complication and revision rates are considerably higher for trauma indications compared to inflammatory pathology (1,4).
Registry data (1,3-4) suggest higher complication and revision rates with lower surgeon caseload volume – a cause for concern with falling numbers of arthroplasties being performed, and leading to calls for these cases to be referred to specialist centres (1).
Total elbow replacement designs
Total elbow designs have been classified as unlinked (unconstrained), i.e. relying on native soft tissue constrains for stability, or linked (constrained or semi-constrained - "sloppy hinges") with inherent stability. Examples of the former include the
Souter-Strathclyde, Kudo and
iBP prostheses, and of the latter
Coonrad-Morrey and
Discovery. Early linked hinge designs suffered from high loosening rates, related mainly to poor understanding of elbow mechanics and fixation methods, but leading to the development of unlinked designs. These can prove problematic in terms of stability, however, which in turn led to linked “sloppy hinge” designs which provide stability but also allow some varus-valgus motion at the joint, preventing excessive forces at the implant/cement/bone interfaces. Most contemporary designs are of this type. The importance is that there is not excessive constraint at the joint. Both linked and unlinked designs can vary in their constraint but contemporary prostheses of both type allow some such joint motion.
More recent developments include the
Acclaim and
Latitude with the ability to be implanted as a linked or unlinked prosthesis. Additional developments are the
Lateral Elbow Resurfacing (LRE) which replaces only the lateral compartment (capitellum and radial head) and distal humeral hemiarthroplasties (e.g.
Latitude) for use in distal humeral fractures.
Unlinked prostheses
There is no randomized trial comparing unlinked design prostheses.
This unlinked design consisted of a short-stemmed metallic humeral component and an all-polyethylene ulnar component. 12-year survivorship of 87% has been reported in rheumatoid arthritis, but with loosening often seen (5). This implant is no longer available.
Kudo
The Kudo unlinked implant consists of a long stemmed humeral component and a polyethylene-on-metal ulnar component. Survivorship of up to 90% at 13 years has been reported (6).
The Instrumented Bone Preserving (iBP) design represents the sixth iteration of the Kudo prothesis, with satisfactory short term outcomes (7).
Linked prostheses
Linked prostheses are the most commonly used contemporary designs, but a comparative study showed no clear difference in outcome between
Coonrad-Morrey, Kudo and
Souter implants (8). However, a systematic review suggested higher loosening rates with unlinked designs (9).
The linked semiconstrained implant most commonly used currently is the Coonrad-Morrey prosthesis, with good long term results in rheumatoid arthritis (10). The humeral component is porous-coated distally and presents an anterior flange, which increases the rotational stability of the implant and neutralizes the extension forces transmitted to the implant interface. The ulnar component has a plasma-spray metallic coating in its proximal third. Both components are intended to be fixed with cement. The components are linked with a cobalt-chrome axis pin, which articulates with the polyethylene bushings of the ulnar and humeral components and allows approximately 10 degrees of varus-valgus and rotational laxity. Problems have been encountered longer-term with wear of the polyethylene bushings.
This is similar design to the Coonrad Morrey overall, but the small bushings in the have been replaced by two hemispherical articulations in an effort to reduce wear, and instrumentation is more anatomical with left and right sided humeral prostheses. No long term data are available on its use.
Convertible Prostheses
These newer designs allow the surgeon to choose linked or unlinked implantation at the time of surgery, depending on stability and other factors, allowing for the advantages and disadvantages of each design to be accounted for.
Whilst superficially similar to the Coonrad Morrey, the Acclaim allows the surgeon to implant as a linked or unlinked prosthesis depending on the indication, intraoperative findings, or secondarily in revision. Short term series in inflammatory cases have been presented with satisfactory results (11).
Again, this design is interchangeable primarily or secondarily between linked and unlinked articulations. However, other features include the option for a radial head replacement along with the ulnohumeral articulation with the aim of improving stability and replicating biomechanics of the native articulation. Additionally, the Latitude humeral hemiarthroplasty (which is anatomically shaped) can be implanted in distal humeral fractures rather than TER. Short term satisfactory results have been reported (12).
Conclusion
Overall, there is good medium to long term evidence for linked semi-constrained implants in the elderly female population for rheumatoid arthritis and trauma, although evidence suggests higher complication rates for non-inflammatory conditions. Also, registry evidence relates survivorship and revision rate to surgeon case load - demonstrating poorer outcomes with lower numbers. There is no clear consensus for any particular type or design from registry datasets, although numbers are generally small, and decreasing. Other evidence for the use of the varying prostheses is lacking.
References:
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2. Garcia J, Mykula R, Stanley D. Complex fractures of the distal humerus in the elderly: The role of total elbow replacement as a primary treatment. Journal of Bone and Joint Surgery (Br) 2002; 84-B: 812-6
3. Gay DM, Lyman S, Do H, Hotchkiss RN, Marx RG, Daluiski A. Indications and reoperation rates for total elbow arthroplasty – an alalysis of trends in New York State. Journal of Bone and Joint Surgery (Am) 2012; 94(2): 110-117
4. Fevang BT, Lie SA, Havelin LI, Skredderstuen A, Furnes O. results after 562 total elbow replacements: a report from the Norwegian Arthroplasty Resister. Journal of Shoulder and Elbow Surgery 2009; 18(3): 449-456
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7. Kleinlugtenbelt IV, Bakx PA, Hull J. Instrumented Bone Preserving elbow prosthesis in rheumatoid arthritis: 2-8 year follow up. Journal of Shoulder and Elbow Surgery 2010; 19(6): 923-928
8. Little CP, Graham AJ, Karatzas G, Woods D, Carr AJ. Outcomes of Total Elbow Arthroplasty for rheumatoid arthritis: a comparative study of three implants. Journal of Bone and Joint Surgery (Am) 2005; 87: 2489-2492
9. Little CP, Graham AJ, Carr AJ. Total elbow arthroplasty: a systematic review of the literature in the English language until the end of 2003. Journal of Bone and Joint Surgery (Br) 2005; 87: 437-440
10. Gill DR, Morrey BF. The Coonrad-Morrey total elbow arthroplasty in patients who have rheumatoid arthritis. A ten to fifteen-year follow-up study. Journal of Bone and Joint Surgery (Am) 1998; 80(9 ):1327–3
11. Bassi RS, Simmons D, Ali F, Nuttall D, Birch A, Trail IA, Stanley JK. Early results of the Acclaim elbow replacement. Journal of Bone and Joint Surgery (Br) 2007; 89-B: 486-489
12. Malone AA, Zarkadas P, Jansen S, Hughes, JS. Elbow hemiarthroplasty for intra-articular distal humeral fracture. Journal of Bone and Joint Surgery (Br) 2009; 91-B Supp 2: 256