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Biomedical subjects

Leo A Whiteside

Publications and source records attributed to Leo A Whiteside.

At least 19 recordsLinked to original sources
PubMed2006

Trochanteric repair and reconstruction in revision total hip arthroplasty.

Repair and reconstruction of the greater trochanter in revision total hip arthroplasty requires a system that achieves rigid fixation of fragile bone stock that often is nothing but a fragmented cortical shell. This fixation must be done with a mechanism that does not disrupt the blood supply and soft tissue attachments to the bone fragments and also does not require extensive stripping of muscle from the femoral shaft. The implants must be absolutely smooth in the region of the trochanter so they can glide under the fascia lata or else be minimally invasive so that they lie under the soft tissues of the femur and thus avoid abrading the overlying fascia. The technique described here uses a cable around the femur and 2 cables over the top of the greater trochanter. The results have been good in 10 of 11 hips. One required reoperation and bone grafting.

Arthroplasty, Replacement, Hip↗
PubMed2006

Mini incision: occasionally desirable, rarely necessary: in the affirmative.

Exposure is a crucial issue in total knee arthroplasty, and the basic surgical principles of exposure apply to the knee just as to other operations. The skin and muscle must not be stretched, and the surgeon must have an excellent view and access to the knee structures. Stretching of the skin or muscles causes damage, hurts the patient, and predisposes to infection. There is no discernable advantage to compromises on exposure to avoid incising the muscle or skin. Many of the advantages credited to smaller skin incisions likely are because of improvements in pain management. Infiltrating with local anesthetics and using shorter tourniquet times may help the patient recover more quickly. Inadequate exposure does not.

Arthroplasty, Replacement, Knee↗
PubMed2006

Cementless fixation in revision total knee arthroplasty.

UNLABELLED: A surgical approach to revision total knee arthroplasty that includes minimal bone resection, minimal soft-tissue stripping, cementless fixation of the femoral and tibial components, and morselized allografting of defects was used and evaluated in 105 patients (110 knees) with severe bone loss. The patients were followed for 60 to 127 months postoperatively. Fixation included a tightly-fit fluted titanium stem in the femoral and tibial canals and rim contact on the peripheral rim of the tibia. One tibia loosened and one knee failed because of infection. Ligamentous stability and pain relief were consistent through the followup period. At 10 years the mean valgus laxity was 4 degrees +/- 2.5 degrees, and the mean varus laxity was 5.2 degrees +/- 3.3 degrees. Mean Knee Society pain score was 47 +/- 2.1. Pain was mild in 28 knees, moderate in eight knees, and severe in two knees. Evidence of bone healing occurred in the bone defects that could be seen on radiographs. Increase in radiodensity always was found at postoperative intervals greater than one year. An approach to revision total knee arthroplasty that maintains bone and soft tissue about the knee establishes an effective and durable construct. LEVEL OF EVIDENCE: Therapeutic study, level II (prospective study). See Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed2006

Revision of the polyethylene component for wear in TKA.

Given reports of failure in isolated polyethylene exchange in well-fixed TKA components, we asked whether isolated exchange could be successful either by replacing the polyethylene in implants whose locking mechanism accepts currently available polyethylene designs or by creating a new locking mechanism fabricated with a carbide bit and augmented with polymethylmethacrylate cement. We performed isolated liner exchange for wear in 46 patients (49 knees). The polyethylene locking mechanism in two total knee designs (13 knees) allowed polyethylene exchange without polymethylmethacrylate fixation. A locking mechanism was fabricated for three implant designs (36 knees). Clinical function after polyethylene component exchange was good in all but three knees. No knees with a fabricated locking mechanism failed. The mechanical strength of the fabricated locking mechanism was tested in the laboratory. The cement- fabricated locking mechanism in the unmodified tray notably outperformed the standard polyethylene locking mechanism. Isolated polyethylene component exchange was successful in this small clinical study. Fabricating a locking mechanism with a carbide bit and acrylic cement was effective in laboratory testing and clinical application.

Aged↗
PubMed2006

Gluteus maximus flap transfer for greater trochanter reconstruction in revision THA.

We evaluated the results of an operative technique used in five patients (five hips) to reconstruct the greater trochanter with a gluteus maximus flap transfer during revision total hip arthroplasty. We exposed the hip through a posterior approach that split the gluteus maximus in its midsubstance. We then raised a flap from the posterior portion of the gluteus muscle that was elevated proximally to create a triangular muscle flap. The flap was sewn into the gap between the greater trochanter and lateral cortex of the femur and secured to the inner surface of the anterior capsule of the hip. With the hip abducted 10 degrees to 15 degrees, the edges of the gluteus maximus were closed over the flap and the greater trochanter. We compared the results of these patients with those of five patients (five hips) who had the trochanter left unrepaired and those of four patients (four hips) who had excision of the greater trochanter and suture closure of the intervening gap. The flap group had less pain, lower incidence of limp and Trendelenburg sign, and less need for support than the other two groups, but range of motion decreased.

Aged↗
PubMed2005

Choosing your implant: cementless, patella sparing, and posterior cruciate ligament retaining.

Clinical results of total knee arthroplasty with osteointegration techniques for fixation of the femoral and tibial components in a series of 192 patients (255 knees) followed up for 15 to 18 years are comparable with the best series reported with cemented fixation. Although functional scores declined as the patients aged, pain scores did not worsen, and the mechanical failure rate remained low through follow-up. Preservation of the posterior cruciate ligament offered knee stability, especially in knees that required ligament balancing. Results with unresurfaced patellas in total knee arthroplasty are superior to resurfaced patellas in qualities related to quadriceps function such as stair climbing, likely because of femoral component design. Femoral implants with a shallow patellar groove and wide intercondylar notch produce the highest stresses on the unresurfaced patella. Those with deeper patellar grooves and supporting lateral flange surfaces have low contact stress similar to that of the normal patellofemoral joint.

Arthroplasty, Replacement, Knee↗
PubMed2005

Making your next unicompartmental knee arthroplasty last: three keys to success.

Alignment, ligament balance, and implant fixation are essential in unicompartmental knee arthroplasty. Adequate exposure allows assessment of the opposite compartment, trimming of medial femoral and tibial osteophytes, and a thorough notchplasty. Intramedullary instruments provide accurate and reproducible alignment of the implants in extension, and the anteroposterior axis offers the best landmark for varus-valgus alignment in flexion and also centers the femoral component on the surface of the tibial component. Complete osteophyte excision frees the collateral and cruciate ligaments and minimizes ligament balancing. The implants should allow 1 to 3 mm of laxity in flexion and extension, and if more laxity is required, reresection should be done posteriorly or distally. Fixation depends on excellent bone stock along with precise alignment, and avoiding tibial overresection ensures adequate support of the implant.

Arthroplasty, Replacement, Knee↗
PubMed2004

Hip mechanics after posterior structure repair in total hip arthroplasty.

This study investigated the rotational response of the hip with different repairs of posterior structures after using the posterior approach in total hip replacement. Five groups were tested: (1) the normal hip without a replacement, (2) the normal hip with a vented capsule, (3) no repair of the capsule and external rotators after total hip replacement, (4) repair of only the piriformis tendon, and (5) repair of the capsule and external rotators as a flap of tissue (capsule, piriformis, obturator internus, gemellae, and quadratus) to the posterior aspect of the greater trochanter. Hemipelvis cadaveric specimens were attached to a joint testing device for testing at full extension, 30 degree, 60 degree and 90 degree hip flexion as internal and external rotation was applied to the femur and the load deflection curves were recorded. Specimens after total hip replacement were externally rotated in full extension until dislocation occurred and the maximum torque was recorded. Each specimen then was rotated internally at 90 degree flexion to the point of dislocation and the maximum torque was recorded for comparison as well. The posterior approach had significantly decreased internal rotational support with no repair or only piriformis repair. When the capsule and external rotators were repaired, a more normal load deflection curve resulted when comparing the full repair group with the normal hip. Significantly higher torque was needed to dislocate the hip in flexion when a full posterior repair was done, and most specimens dislocated in flexion without complete failure of the repair.

Arthroplasty, Replacement, Hip↗
PubMed2004

Anatomic consideration of nerve supply to the vastus medialis in knee surgery.

A medial approach for exposure of total knee arthroplasty that splits the vastus medialis muscles may damage the distal portion of the muscle. Ten fresh-frozen cadaver knees without deformity and three retrieved knees were used to dissect nerve branches along the femoral nerve distally until they ended in muscle. Two patterns of nerve distribution were observed. In three specimens, the main trunk ran in the midportion of the vastus medialis and then divided into multiple branches which entered the distal oblique fibers of the muscle at multiple points in the area where it blended with the main body of the muscle. In the remaining specimens, the main trunk ran in the posterior portion of the muscle and branched to the distal oblique fibers, but many branches entered these distal oblique fibers diffusely through the proximal area from branches in the main body of the muscle. No nerve branches were found crossing between the vastus intermedius and vastus medialis. These muscles appear to be innervated separately by direct branches from the femoral nerve. Dissecting between the vastus intermedius and medialis is unlikely to damage the nerve supply to the vastus medialis obliquus whereas dissecting between the vastus medialis obliquus and main body of the vastus medialis may damage the nerve supply of both.

Arthroplasty, Replacement, Knee↗
PubMed2004

Ligament balancing in revision total knee arthroplasty.

Ligament balancing in revision total knee arthroplasty involves placement and sizing of the femoral and tibial components and balancing procedures for the ligaments. A simplified technique is presented for sizing and positioning the implants and for balancing the ligaments. Eighty-nine knees with severe bone loss were treated with ligament-sparing exposure and bone-sparing resection techniques. The knees were stabilized by the spacer effect of the implants in flexion and extension, and nonlinked components were used. None of the knees had symptomatic instability, recurvatum, or flexion contracture. Five years after surgery the mean valgus laxity was 3 degrees +/- 2.5 degrees and the mean varus laxity was 4.5 degrees +/- 3.3 degrees Laxity did not increase after 10 years followup. The techniques used in this series have proven to be simple and reproducible, and to provide long-term reliability.

Adult↗
PubMed2004

Effect of tibial slope or posterior cruciate ligament release on knee kinematics.

An experimental study using fresh human cadaver knees was designed to evaluate the effect of partial posterior cruciate ligament release or posterior tibial slope on knee kinematics after total knee arthroplasty. Varus and valgus laxity, rotational laxity, anteroposterior laxity, femoral rollback, and maximum flexion angle were evaluated in a normal knee, an ideal total knee arthroplasty, and a total knee arthroplasty in which the ligaments were made to be too tight in flexion. The total knee arthroplasty specimens then were subjected to either partial posterior cruciate ligament release or increased posterior tibial slope, and the tests were repeated. Posterior tibial slope increased varus and valgus laxity, anteroposterior laxity, and rotational laxity in the knee that had flexion tightness. Posterior cruciate ligament release corrected only anteroposterior tightness, and had no effect on the abnormal collateral ligament tightness. Increased posterior tibial slope significantly improved varus and valgus laxity and rotational laxity in the knee that was tight in flexion more than with release of the posterior cruciate ligament. Therefore increasing posterior tibial slope is preferable for a knee that is tight in flexion during total knee arthroplasty.

Arthroplasty, Replacement, Knee↗
PubMed2004

Major femoral bone loss in revision total hip arthroplasty treated with tapered, porous-coated stems.

Clinical results of revision total hip arthroplasty using fully porous-coated tapered titanium stems to treat severe proximal femoral bone loss were evaluated in a retrospective review of 39 patients (45 hips). The bone was reinforced with cables in 39 hips, and in 14 hips strut allografts were added. Fixation was successful in 44 hips, and one hip required revision to treat undetected fracture and migration of the stem. All the others had radiographic evidence of bone attachment. Neither bone atrophy nor reconstitution was noted. Three patients (3 hips) had mild thigh pain, but the others had no pain related to the femoral component. Eight hips dislocated; one resolved and seven had recurrent dislocation that was treated with a constrained acetabular component, capsulorrhaphy, or liner reorientation. Ten patients (12 hips) used a walker and 10 patients (12 hips) used a cane at the last postoperative visit. Whereas fixation was successful with this surgical technique, complications related to deficiency of the soft tissue structures were common.

Adult↗
PubMed2003

Bone resection and ligament treatment for flexion contracture in knee arthroplasty.

A retrospective study of 103 knees (88 patients) who had primary total knee arthroplasty with a flexion contracture ranging from 20 degrees to 60 degrees was done to tabulate the primary soft tissue structures released during surgery and to identify any residual deformity. The average flexion contracture preoperatively was 27.1 degrees +/- 8 degrees and postoperatively was 2.7 degrees +/- 3.4 degrees (range, 0 degrees -10 degrees ). The average followup was 70.4 months (range, 12-180 months). Only medial or lateral soft tissue balancing procedures were necessary to correct the flexion contracture in 37 knees (35.9%) and no medial or lateral release was necessary in 25 knees (24.3%), of which 16 had a balanced posterior cruciate ligament. The posterior capsule was released on the deformity side of the knee in 15 knees (14.6%) and on the opposite side of the deformity in seven knees (6.8%). The posterior cruciate ligament was balanced in 21 knees (20.4%) and was released in four knees (3.9%). For all knees in which the posterior cruciate ligament was released or balanced, it was done for excessive rollback and tightness in flexion and not for flexion contracture management. In two patients (2%) an additional 4 mm of distal femur was resected for a 45 degrees and a 25 degrees flexion contracture. The data suggest that a contracted collateral ligament is the most likely primary structure whose effective release allows correction of the flexion contracture in most cases.

Arthroplasty, Replacement, Knee↗
PubMed2003

Knee motions during maximum flexion in fixed and mobile-bearing arthroplasties.

Full flexion is a critical performance requirement for patients in Asia and the Middle East, and increasingly for patients in Europe and North America who have total knee arthroplasty. There has been considerable work characterizing maximum flexion in terms of clinical, surgical, and preoperative factors, but less in vivo experimental work after rehabilitation. The purpose of the current investigation was to determine whether anteroposterior tibiofemoral translation influenced maximum weightbearing knee flexion in patients with good or excellent clinical and functional outcomes. One hundred twenty-one knees in 93 subjects, including 16 different articular surface designs, were studied using fluoroscopy and shape matching to determine knee kinematics in a weightbearing deep flexion activity. A relatively posterior position of the femur on the tibia was significantly correlated with greater maximum knee flexion. Posterior-stabilized arthroplasties had significantly more posterior femoral position and maximum flexion than posterior cruciate-retaining fixed-bearing arthroplasties, which had more posterior femoral position and greater maximum flexion than mobile-bearing arthroplasties. Posterior bone-implant impingement was observed in 28% of knees. Tibiofemoral motions influence the mechanics of weightbearing deep flexion in well-functioning knee arthroplasties.

Aged↗