Ch 53 Total elbow replacement Flashcards
(19 cards)
What are some recent technological advances for total elbow replacements in dogs in general?
- Resurfacing, rather than screwed or stemmed components
- Titanium, rahter than cobalt chrome alloy
- ELetron beam melthing rather than bead sintering for interface surface texture
first designs: cemented, fully constrained hinged (linked systems)
TER indications
severe, intractable osteoarthritis that is not responsive or is poorly responsive to medical management
- risk of potentially severe complications and with limited revision strategies, preferentially performed in dogs with unilateral elbow osteoarthritis
- limited long-term follow-up available for the currently available systems, recommended replacement be restricted to older dogs
- When extensive periarticular osteophytes are present, a computed tomography (CT) scan with three-dimensional reconstruction of the elbow is useful for surgical planning.
Iowa State Elbow in 2001
TATE Elbow in 2008
SIRIUS Elbow in 2011.
What implant in this?
Decribe some of the features of this implant
unlinked semiconstrained two-component
5th generation Iowa State TER
- Cemented system
- Cobalt chrome humeral component
- 120deg arc UHMW polyethylene r/u component
- Porpous coated condylar surface for bone ingrowth
- humeral and radioulnar components are implanted individually in sequence
- lateral collateral ligament desmotomy + elbow joint fully luxated
- complete wedge resection of the humeral condyle and radius/ulna
- humeral and radioulnar components are sequentially cemented in place
- cancellous bone graft is inserted between the two bones, and a distal ulnar ostectomy is performed proximal to the styloid process
What impant is this?
Describe some of the features of this implant
unlinked, semiconstrained, cementless resurfacing arthroplasty system
TATE 3rd generation
- Press-fit, cementless, resurfacing design
- Titanium 3D printed humeral component and r/u backing
- Titanium nitride coating of articular surface of humeral component
- Hydroxyapatite coating of metal-bone interfaces
- 175 degree arc UHMT polyethylele r/u component with titanium backing
- Less invasive approach medial osteotomy (During implantation, both components are linked by a set plate and are inserted simultaneously “cartridge implant”)
- Posts for primary fixation are hollow and porous surface for long term stability
- osteotomy of the medial epicondyle
- elbow joint is flexed to approximately 90 degrees and then is locked in place
- custom end mill, articular surfaces are simultaneously removed
What impant is this?
Describe some of the features of this implant
unlinked semi-constrained hybrid
SIRIUS 2.0
- unlinked semi-constrained
hybrid
- osteotomies are conservative, preserving sufficient bone stock + maintaining the stress field on the distal humerus
- humeral component bears a gap between
the humeral forks for passage of the
radio-ulnar implant (optimise ROM)
- a single distal component, fixed to
the ulna only, and combined with a radial
head excision
- The radioulnar bearing is snap-fitted to a stemless, screw-fixed titanium plate with porous titanium and hydroxyapatite dual coating
- radial difference exists between the articular surfaces of the two components to decrease constraint thereby allowing for a degree of rotational movement
- press-fit of the condylar part and cement fixation of the stem (hybrid)
SIRIUS
No clinical studies
- no clinical studies
- design enable some joint laxity.
- The pre-implantation ROM in the sagittal plane was 115°, which decreased to 90° post-arthroplasty
- proposed SIRIUS 3.0 system has changed to a linked, semiconstrained prosthesis to adress post-op instability linked systems now dominate the human TER market.
What implant is this?
Describe some of the features of this implant
kyon - no further development?
BANC (Biomechanically Anatomic, Nonconstrained and Compartmental)
- Non-cemented, resurfacig design
- UHMW polyethylene conican disc press fitted over titanium cylinder and screwed into capitulum
- Shape-matched polished titaniumhemicircular component
- Primary fixation with large transcondylar screw and 2 smaller ulnar screws
IOWA and TATE
current 2 component design
- stability of unlinked prostheses is provided by the matching geometry of the prosthetic articulating surfaces and the surrounding soft tissue envelope
- transarticular forces (e.g., the forces in varus-valgus) are almost exclusively counteracted by passive soft tissue constraints (i.e., collateral ligaments),
- internal/external rotation and mediolateral translation are also controlled by the geometry of the prosthetic .
- prosthetic constraint has been shown to influence stresses at the bone-implant interface.
- single radioulnar component that eliminates motion between the radius and the ulna.
- the surgical procedure includes a radioulnar synostosis
What are potential contraindications of a TER?
Bilateral elbow OA (limited revision options)
Systemic or local infections
Chronic elbow luxation
Severe malunion (Iowa state may still be ok)
Neuro dysfunction
Skeletally immature
What are the main differences in the surgical procendures for the Iowa state, TATE and BANC elbow replacements?
post-op TER
rads: implant alignment and positioning and, when appropriate, cementing technique and bone-cement-implant interfaces, as well as osteotomy reduction and fixation. Subsequent radiographic evaluations are recommended at 6, 12, 24, and 52 weeks, then yearly thereafter, to assess bone ingrowth as well as implant stability
What are the main complications seen with the Iowa State system?
Intraoperative: instability of the lateral aspect of the elbow joint and iatrogenic fracture of the humerus
- Elbow joint luxation
- fractures of the ulna
- osteomyelitis
20% Severe complications leading to unsatisfactory results
Force plate evaluation of the remaining 16 dogs showed significant and continuous improvement in peak vertical force
What are the main complications seen with the TATE elbow?
Humeral fractures
Implant malpositioning or loosening
infection (30%)
luxations have not been reported possibly because not ligament desmotmy
STUDY: Retrospective study, the long-term subjectively evaluated - “full” (24%) or acceptable (52%) function, 24% of the cases had unacceptable clinical outcomes. high rate of major (15 cases [45%]) or catastrophic (5 cases [15%]) complications
Suboptimal implant positioning in 97%
Major/catastrophic complications range from 4-65%
MINOR 8% (migration, neuropraxia
Steep learning curve
By 6-12 months, peak vertical ground force reaction better than contralateral limb and by 2yr had reached a normal value
TATE elbow
- very few peer-review publications relate to this system.
- Function was subjectively evaluated as acceptable in 76% of clinical cases, although perioperative complications, most major in 60%
major limitation of total elbow replacement
absence of effective revision options in case of failure
Unfortunately, because end-stage elbow joint osteoarthritis is often a bilateral condition, amputation is not a valid option in most cases, and arthrodesis remains the main alternative
Infection is and will likely continue to be the most challenging complication > treated by explantation and arthrodesis.
unilateral arthrodesis, however, limb function has been described as acceptable in most cases, despite continuous limb circumduction.
questions regarding optimal articular surface constraint and long-term periprosthetic osteolysis or osteointegration
Evaluation of the milling technique on the component-bone
interface in the TATE elbow
Gosling 2019
ex vivo effect of milling technique on component-bone interface
- divergence or convergence during milling → component-bone interface gaps and poor
post-fit
- influenced by surgeon by pressure on milling arm
- failure to maintain neutral position during milling affected implant fit
(osseointegration > aseptic implant loosening)
In man, accuracy “press fit” > influence the success rates
A lateral approach allows accurate and stable total elbow replacement in dogs
Woody 2024
12 cadavers, lateral or medial compared, using patient-specific guides
Lateral > produced equivalent limb alignment, laxity, and motion to normal elbows and to routine medial approach.
* medial > transection branch ulnar nerve and origin humeral head of flexor carpi ulnaris.
* patient-specific guides recommended
STUDY (de sousa): review of 33 TATE TER in dogs did not identify an association between implant alignment and clinical outcome. However, long-term data were limited in that study. Full function in 24%, acceptable 52%
The use of subchondral bone topography to approximate the center of rotation of the elbow joint in dogs
Berger 2023
CT-assessment of centre of rotation of the elbow joint for total elbow replacement
- COR in fMCP affected elbows was more caudal
- normal joint: medial: 74% axes exited cortex cranial and distal to medial epicondyle
lateral: 93% axes exited cortex cranial and distal to lateral epicondyle
- diseased joint: medial: 81% axes exited caudal and distal to medial epicondyle
lateral: 70% axes exited caudal and distal to lateral epicondyle
