We retrospectively reviewed the records of twelve consecutive
patients who had undergone revision total elbow arthroplasty with cement and
impacted allograft bone between 1993 and 1997. All of the revisions were done
with the use of a titanium linked semiconstrained prosthesis. A minimum
duration of follow-up of two years was required for inclusion in the study.
There were four men and eight women with an average age of fifty-seven years
(range, thirty-seven to eighty years). Three of the patients underwent the
impaction grafting at the initial revision procedure, and the remaining nine
patients had undergone at least one prior revision (average, 2.1 [range, one
to four] prior revisions). One patient had the total elbow arthroplasty after
a prior resection arthroplasty. The presenting diagnosis was rheumatoid
arthritis in seven of the patients and posttraumatic arthritis in five.
The indication for the revision arthroplasty was aseptic loosening in all
twelve patients. Ten patients presented with pain and radiographic evidence of
prosthetic loosening and osteolysis, with one of the ten presenting with a
periprosthetic fracture as well. The other two elbows were painless but had
radiographic evidence of loosening of either the humeral or the ulnar
component. Those two elbows had progressive resorption due to particulate
debris or had mechanical resorption, and the revision was performed to prevent
further bone destruction and thereby prevent a periprosthetic fracture.
Eight patients had revision of both the ulnar and the humeral component,
one patient had only the humeral component replaced, and three had only the
ulnar component revised. In all cases, the bushing was exchanged. Two patients
underwent impaction grafting in both the humerus and the ulna; four patients,
in the ulna only; and six patients, in the humerus only. Two patients had
additional allograft strut grafts placed on both the ulna and the humerus to
span structural defects and to retain the bone graft. Two patients had
allograft strut grafts placed only on the ulna, and one patient had strut
grafts placed only on the humerus. Seven patients had no strut graft
augmentation.
Implant
A linked semiconstrained Coonrad-Morrey prosthesis (Zimmer, Warsaw,
Indiana) was utilized in ten patients. This device is the third-generation
design, incorporating a loose hinge that allows 7° to 10° of laxity in
the varus-valgus plane and in axial rotation. The device is available in 100,
150, and 200-cm lengths, with either a small or a standard humeral component.
The humeral component has an anterior flange on its distal portion to resist
posterior displacement and torsional stresses on the humeral component when it
is incorporated with bone graft. In one patient, a customized humeral
component of similar design was used to compensate for severe bone loss. The
ulnar component is available in small (76.2-mm), standard (88.9-mm), and long
(101.6-mm) lengths. Extremely small ulnar canals may require an extra-small
implant. The small-diameter ulnar implant is also available in an extended
length to bypass olecranon fractures, areas of avascular change, or lytic
segments due to loosening or wear. Three patients were treated with a standard
ulnar component; six, with a small ulnar component; and two, with an
extra-long, extra-small component. In one patient, an extra-smooth, extra-long
custom ulnar component was used. Strut-grafting may be used with this
prosthesis when conditions warrant.
Operative Technique
The operative technique for revision total elbow arthroplasty has been
described
previously12. In
brief, a straight posterior skin incision is utilized unless concern about the
viability of subsequent skin bridges mandates the use of prior incisions. When
a posterior approach to the elbow is used, the ulnar nerve must be identified
and protected. This should be the initial step in most revision procedures.
Even if the nerve has been moved, it must be identified proximally to
ascertain its location. If it has not been translocated, the nerve is isolated
and is dissected free to its first motor branch. Sometimes this can be
difficult. If dense scarring or deformity is present, magnification loops and
possibly a nerve stimulator are used. The Mayo triceps-reflecting approach was
utilized in all twelve patients. This approach exposes the elbow joint through
lateral reflection of the triceps from the olecranon in continuity with the
ulnar periosteum and the fascia of the forearm along with the anconeus. After
the triceps has been adequately removed to expose the ulna and the medial and
lateral aspects of the humerus, a subperiosteal exposure of the ulna,
extending past the tip of the implant to be revised, is performed. This allows
palpation of the very thin cortex, which helps to minimize the likelihood of
penetration or fracture at the time of preparation for the revision. Bone is
then removed from the anterior aspects of the condyles for disarticulation of
the components.
After complete exposure of the elbow joint, the failed prosthetic
components are removed. It is important for the surgeon to note whether both
components have failed. If one component is solidly fixed, the articular
bushing is exchanged but the component is left intact. This decision is made
at the time of the surgery, but a matching humeral or ulnar component must be
made available before the procedure. Attempts are made to remove all loose
bone cement; however, firmly adherent cement is left in place if it does not
interfere with the placement of the revision component. The availability of a
long-stemmed high-speed bone burr and an ultrasonic cement-removal system has
been extremely helpful. When revising the humeral component, we have often
found it necessary to expose the radial nerve and to protect it during cement
removal. At a minimum, the nerve should be palpated and protected against
laceration or injury.
When necessary, allograft strut grafts are used to stabilize fractures and
to supplement the outer cortex of diaphyseal bone if an area was perforated or
deemed too thin to withstand the stresses of impaction grafting. These strut
grafts are secured to the shaft of the ulna and/or humerus with 16 or 18-gauge
cerclage wires. At least two wires are utilized, and three or four are used if
a periprosthetic fracture is present.
The impaction grafting technique involves reconstitution of the medullary
canal with allograft cancellous bone. Initially, all endosteal soft tissue is
carefully removed and the canal is plugged with a silicone device or with
cancellous bone. The allograft is initially processed in a bone mill to obtain
a uniform consistency of finely morselized bone.
Two general methods have been used in our attempts to perform impaction
grafting. In the first, a "double tube" apparatus is assembled for
the impaction-grafting portion of the procedure
(Figs. 1-A and 1-B). The nozzle
of tubing used for femoral cementation is cut to the length that corresponds
to the extent of the lytic process and is used as the outside tube. The elbow
cement-injector tube is then inserted into the femoral tube and is extended
distally into normal host bone to the depth necessary to fix the selected
length of the component. Cancellous bone graft or graft substitute is tightly
packed around the outer tube with care taken to keep the tubes from bending.
The cement is then mixed in the canister of the elbow injector system and is
inserted on the nozzle in situ. Cement is injected through the nozzle while
the inner tube is withdrawn to the level of the outer tube (Figs.
2-A,
2-B, and
2-C). At this point, both the
inner and the outer tubes are simultaneously withdrawn while cement is
injected into the void created by the larger tube. The implant is carefully
inserted to the desired length and is left undisturbed until the cement has
fully cured. If both sides require impaction grafting, the ulnar side should
be treated first since this will not compromise the humeral exposure.
The second method of impaction grafting involves reconstitution of a
"neomedullary canal." After any segmental cortical defect or
substantial cortical thinning has been augmented with secured allograft
struts, morselized cancellous allograft bone is firmly packed to fill the
medullary canal. The cancellous graft is then compressed with the use of
appropriately sized punches, tamps, and prosthetic trials; more graft is added
until the trial prosthesis can be securely held in position. The final
prosthesis is also used as an impactor. The principal goal is to obtain
centrifugal impaction. The graft is compressed stepwise from distal to
proximal in the ulna and from proximal to distal in the humerus. Once the
neomedullary canal has been created, it is filled with cement with an
injection gun. Pulsed lavage is avoided to prevent dislodgment of the impacted
bone.
If an extensive dissection has been carried out, the tourniquet should be
released and hemostasis should be obtained prior to cementation. The arm is
elevated for twenty-four to thirty-six hours postoperatively. The patient uses
the extremity as tolerated if there are no wound problems. He or she is
discharged from the hospital in about three to five days, with instructions to
use the extremity as dictated by functional demands. Physical therapy is not
routinely needed or prescribed. The postoperative recommendation is that the
patient not lift >4 to 5 kg as a single event or >1 kg on a repetitive
basis.
Evaluation of the Patients
All patients were examined clinically at a minimum of two years, and an
average of sixty-two months, after implantation of the prosthesis with
impaction grafting. Seven patients were assessed at our institution, at a mean
of seventy-five months (range, forty-five to 101 months), and five were
examined by a local orthopaedist, at a mean of forty-three months (range,
twenty-five to fifty-four months). In addition, more information about three
patients was obtained from a detailed questionnaire, increasing the clinical
follow-up of those patients to fifty-three, ninety-six, and 113 months. Thus,
the overall surveillance period averaged seventy-two months (range,
twenty-five to 113 months). Data for this study were subsequently assembled
through analysis of the patient records in the computerized database.
The Mayo Elbow Performance Score (MEPS) was utilized to characterize the
outcomes of the procedures. The maximum total score is 100 points, with 45
points for pain, 20 points for motion, 10 points for stability, and 25 points
for activities of daily living. A postoperative result was classified as
excellent when the score was =90 points, good when it was 75 to 89 points,
fair when it was 60 to 74 points, and poor when it was <60 points.
Radiographic Evaluation
All elbows were evaluated with anteroposterior and lateral radiographs at a
mean of fifty-eight months (range, twenty-five to eighty-four months) after
the operation. The radiographs were assessed for the presence of progressive
radiolucent lines as well as for the presence and incorporation of bone graft
placed behind the anterior flange of the humeral component. Type 0 indicated
no radiolucent line or an incomplete line of <1 mm in width at the
bone-cement interface. Type I indicated an incomplete radiolucent line of 1 to
2 mm in width. Type II indicated an incomplete line of >2 mm in width. Type
III indicated a complete radiolucent line of >2 mm in width. Type IV
represented gross loosening and a shift in the position of the implant.
Stability of the elbow was considered adequate if radiographs showed the
humeral and ulnar components to be linked with no evidence of loosening.
The index revision implant was functioning at the time of follow-up
in eight of the twelve patients who had undergone impaction grafting (Figs.
3-A through
3-D). Six of the twelve
patients had undergone additional procedures. One underwent a resection
arthroplasty because of deep infection two years after implantation. One
patient underwent a repeat revision of both components, also with use of
impaction grafting techniques. A third patient had two subsequent procedures.
Four months after the impaction grafting, that patient underwent a repair of a
ruptured triceps tendon, which was followed, at nine months, by open reduction
and internal fixation with autogenous bone-grafting of a periprosthetic
fracture distal to the tip of the ulnar component. The fourth and fifth
patients, who had undergone impaction grafting around the humeral component,
underwent impaction grafting around the ulnar component because of osteolysis
six years later. The humeral component that had been inserted with impaction
grafting previously was solidly fixed and was not revised. The sixth patient
had a revision of a fractured extra-long, extra-small custom ulnar component
eighty-four months postoperatively. It was possible to use a standard-length
ulnar component for this revision as the impacted bone and allograft struts
were solidly incorporated. The fractured distal part of the stem was well
fixed in bone, and a window in the distal part of the ulna was required to
remove it. There was proximal osteolysis, which may have been related to the
use of a polymethylmethacrylate precoat on the ulnar component, a feature that
has been noted to increase the risk of
osteolysis1.
The average preoperative Mayo Elbow Performance Score (MEPS) was 55 points
(range, 20 to 85 points), and the average postoperative score was 83 points
(range, 55 to 100 points). Before the surgery, none of the elbows were
classified as excellent according to the MEPS; three were classified as good;
one, as fair; and eight, as poor. Eleven patients had an improvement in the
MEPS postoperatively, and one patient, who had had a resection arthroplasty
secondary to infection, had a decrease from good to fair. At the time of the
study, after the reoperations in the four patients, there were five excellent,
four good, and three fair results.
Pain
Preoperatively, seven of the twelve patients characterized the pain in the
elbow as severe; three, as mild/moderate; and two reported that they had no
pain. At the most recent follow-up evaluation, five had no pain, six had
mild/moderate pain, and one had severe pain. The patient who characterized the
pain as severe after the revision with impaction grafting had undergone a
second revision with impaction grafting, but this procedure did not result in
any additional pain relief. Overall, the average score for the pain component
of the MEPS improved from 23 points (maximum, 45 points) preoperatively to 36
points at the most recent evaluation.
Range of Motion
The average arc of flexion of the operatively treated elbow improved from
86° before the impaction grafting procedure to 99° after it. The
average range of motion before the surgery was from 29° of extension
(range, -15° to 60°) to 114° of flexion (range, 70° to
145°). The average range of motion after the surgery was from 25° of
extension to 123° of flexion. Six of the twelve patients had a functional
arc of motion from at least 30° of extension to 130° of flexion. Four
other patients had motion in a range of 40° to 120°. Two patients did
not obtain a functional range of motion.
Stability
All of the patients who retained the prosthesis had a stable elbow joint.
The one patient who had undergone resection arthroplasty because of infection
had moderate instability.
Function
The ability of each patient to perform five tasks of daily function
(combing hair, feeding oneself, tending to personal hygiene, putting on a
shirt, and putting on shoes) was assessed with the MEPS both before and after
the surgery. The preoperative functional score averaged 11 points (range, 0 to
25 points), with a maximum possible score of 25 points, and the postoperative
functional score averaged 20 points (range, 0 to 25 points).
Radiographic Assessment
Radiographs made at least twenty-four months (average, fifty-eight months;
range, twenty-five to eighty-four months) after the impaction grafting
procedure were available for all twelve patients, one of whom had undergone
resection arthroplasty because of infection. Preoperative radiographs had
demonstrated evidence of extensive periprosthetic osteolysis and of loosening
in all patients. Of the fourteen components that had been fixed with the
impaction grafting technique, six were classified as Type 0; four, as Type I;
four, as Type II; and none, as Type III or IV.
Postoperative Complications
Six of the twelve patients had complications, which required surgery in
five of them. Two patients demonstrated symptoms and radiographic signs of
loosening and underwent revision. One of those patients underwent a second
impaction grafting procedure thirty-one months after the initial impaction
grafting procedure on the humerus and ulna. At the revision procedure, both
components were revised with impaction grafting techniques.
A deep infection that necessitated removal of the implant developed in one
patient twenty-seven months after implantation. One patient was diagnosed with
a triceps rupture, which was repaired four months after the surgery, and a
periprosthetic fracture of the ulna, which was fixed nine months after the
index procedure. Both healed well. A symptomatic ulnar neuropathy developed in
one patient, and one patient was diagnosed with a radial nerve palsy after the
surgery. A third patient had objective weakness in the thumb of the involved
extremity. All of those problems resolved early without additional
intervention.