Minimally invasive hip surgery techniques have been advocated as an
alternative to total hip arthroplasty performed with conventional soft-tissue
exposure. Purported advantages of the minimally invasive technique have
included faster functional recovery, a shorter stay in the hospital, less
blood loss, and an improved cosmetic
result1.
Any new surgical technique involves a learning curve. The steepness of this
curve and the true complication rates cannot be established until these
procedures have been performed by surgeons other than those who champion the
technique. Ideally, before any new procedure is adopted for widespread use,
prospective, controlled, multicenter studies should prove the procedure's
safety and efficacy.
Recently, three patients with catastrophic complications of minimally
invasive hip replacement were referred to our tertiary total joint revision
center. Each arthroplasty had been performed by a different orthopaedic
surgeon who stated, in his operative note, that a minimally invasive approach
had been used. Two of the patients consented to have data concerning the case
submitted for publication, whereas the third patient died in the recovery room
after being directly transferred from an outside clinic to our hospital. Thus,
she did not sign the release form at the clinic.
Case 1. A sixty-seven-year-old woman underwent a primary
total hip arthroplasty that was performed with use of minimally invasive
techniques at another institution. The patient was 5 ft and 6 in (167.6 cm)
tall and weighed 180 lb (81.6 kg). The procedure was performed through a 9-cm
incision. During the operation, difficulty with reaming of the acetabulum was
encountered and a segmental defect in the superior dome of the acetabulum was
created. The defect was recognized intraoperatively, but no suitable revision
components were available and the surgeon called our institution requesting
transfer of the patient to our care.
Two days after admission to our institution and following medical
clearance, revision surgery was performed. When the acetabulum was exposed, we
noted a large superior segmental defect that included complete loss of the
superior margin of the acetabulum to the depth of the quadrilateral plate. The
defect was managed with a trabecular metal augment and a revision acetabular
component (Fig. 1).
Case 2. A fifty-five-year-old, 5-ft (152.4-cm) tall, 150-lb
(68-kg) woman underwent a primary total hip replacement at another
institution. The surgeon used an anterolateral approach and performed the
procedure through an 8-cm incision. Postoperative radiographs revealed
vertical placement of the acetabular component with an abduction angle of
64°.
Postoperatively, the patient sustained multiple dislocations, which
required revision arthroplasty five months after the initial procedure
(Fig. 2-A). At the time of the
revision, avulsion of the abductor muscles was noted. A modular exchange of
the polyethylene along with a repair of the abductor muscles was performed on
two different occasions by the original surgeon. Neither procedure was
successful in stabilizing the hip.
Five months later, the original surgeon performed a third revision because
of recurrent dislocation. In addition to the malpositioned acetabular
component, which was removed, a large posterior wall defect and a pelvic
dissociation were noted. A bipolar hemiarthroplasty was performed as a
temporizing procedure, and the patient was transferred to our institution for
definitive care. We performed computerized tomography with pelvic
reconstructive software to delineate the acetabular pathology more clearly. We
interpreted these images as showing a transverse acetabular dissociation with
substantial loss of the posterior wall
(Fig. 2-B). A triflanged custom
acetabular component was used to reconstruct the hip.
Case 3. A seventy-five-year-old man with degenerative arthritis
of the hip, who was 5 ft and 8 in (176.5 cm) tall and weighed 190 lb (86.2
kg), was adamant about having the "new two-incision technique for hip
replacement." The patient's local orthopaedist was reluctant to do this
procedure and referred the patient to another physician who had limited
experience with this technique.
The patient underwent a minimally invasive total hip arthroplasty performed
with the two-incision technique (Zimmer, Warsaw, Indiana). The operative time
was noted to be nine hours and thirteen minutes in the anesthesia records.
Surgery was complicated by a failure to obtain proper broach orientation,
resulting in a comminuted fracture of the greater trochanter. The fracture was
treated with cable-grip fixation after extension of the posterior incision.
Postoperatively, the patient did poorly and was referred to our center for
evaluation.
At the time of presentation to us, nine months following the original
arthroplasty, the patient required a cane to walk. He had a strongly positive
Trendelenburg sign and a severe Trendelenburg lurch. The anterior scar
measured 7 cm, and the posterior scar measured 16 cm. The patient was unable
to abduct the lower limb above neutral when lying in a lateral position.
Radiographs revealed a comminuted, ununited fracture of the greater trochanter
with loose hardware and metal debris (Fig.
3).
The patient was very dissatisfied with the severe Trendelenburg lurch and
the need for a cane. We were concerned that, because of the comminuted nature
of the fracture and the surgical dissection that would be required to
reconstruct a functioning abductor mechanism, we might further destabilize a
hip that already felt unstable to the patient but had not yet resulted in a
frank dislocation. After thoughtful consideration, surgical intervention to
repair the trochanteric non-union was not offered to the patient.
We recognize that the catastrophic complications reported here came
from an unknown denominator of patients undergoing minimally invasive
procedures in our referral area. Each of these patients was referred by a
surgeon who considered himself to be a general orthopaedic surgeon and who did
not have fellowship training in adult reconstructive surgery. Two surgeons
practiced in small cities (with populations of 23,000 and 49,000) outside a
major metropolitan area, while the third surgeon practiced in a medium-sized
city (population of 100,000) within an hour of a major tertiary medical
center. One surgeon commented that he was always quick to adopt new techniques
for fear of losing patients to a larger center. The average number of total
hip implants performed by these three general orthopaedists each year was
highly variable. The surgeon who treated the first patient (Case 1) performed
only approximately fifteen total hip replacements a year; the surgeon who
treated the second patient (Case 2), approximately fifty per year; and the
surgeon who operated on the third patient (Case 3), approximately 100 per
year. Only one of the surgeons had taken a course in minimally invasive hip
surgery before performing the technique. The number of minimally invasive hip
arthroplasties that each surgeon had performed before these complications
occurred was fifty, twenty, and thirty, respectively. Despite the severity of
these complications, each of these surgeons still performs minimally invasive
hip surgery.
Ideally, the safety and efficacy of any new surgical procedure or technique
should be studied carefully before it is accepted for general use.
Unfortunately, this has not been the case with regard to minimally invasive
hip surgery. The Internet and direct-to-consumer advertisements have
encouraged patients to seek new treatments before traditional peer review has
been completed1. The
peer-reviewed literature comparing standard and minimal-incision hip surgery
is limited. Goldstein et
al.2 noted a
significant decrease in estimated blood loss (p = 0.0001) but no significant
difference in the transfusion rate or in the six or twelve-week Harris hip
score with the minimal-incision technique. DiGioia et
al.3 found that the
minimally invasive approach resulted in a significant improvement with regard
to limping (p < 0.05), distance walked (p < 0.001), and stair-climbing
ability (p < 0.001) at six months. However, there was no significant
difference between groups with regard to pain, function, or range of motion at
one year. Wright et
al.4 found that the
minimally invasive technique resulted in no significant difference in blood
loss or the length of stay in the hospital.
Woolson et al.5
reported no significant difference between the standard and mini-incision
techniques with respect to surgical time, intraoperative blood loss, hospital
transfusion rate, or length of stay in the hospital. However, the group
treated with the mini-incision was found to have a significantly higher risk
of wound complications (p = 0.02), malposition of the acetabular component (p
= 0.04), and poor fit and fill of femoral components inserted without cement
(p = 0.0036).
It is not the purpose of this report to either condemn or condone minimally
invasive techniques. We recognize that complications occur with any type of
hip replacement.
While the theoretical benefits of minimally invasive surgery are
intuitively obvious, the steepness of the learning curve and the complication
rate have not yet been defined. Practitioners must decide what level of
evidence demonstrating safety and efficacy is needed before they consider
using a minimally invasive technique for their
patients1.
Practitioners should resist pressure from their peers, their patients, or
industry regarding any new surgical techniques before these techniques are
validated in rigorously controlled studies.
We recognized that, without innovation, there can be no progress. Patient
safety, however, must be ensured before widespread use of any new technique is
advocated. ?