PubMed Health⌕ Search

Biomedical subjects

Thomas P Sculco

Publications and source records attributed to Thomas P Sculco.

At least 19 recordsLinked to original sources
PubMed2007

Ultimate outcome in immediate postoperative total hip arthroplasty instability.

The objective of this study was to determine the ultimate outcome of patients who experienced immediate postoperative instability after primary total hip arthroplasty using regional anesthesia. Thirty-one patients whose radiographs demonstrated dislocation or subluxation immediately after total hip arthroplasty were evaluated as to the ultimate outcome of hip function and stability. Once a dislocation has occurred, the risk of redislocation is high. In this study, of the 29 patients who did not have revisions immediately after surgery, 3 (10.3%) have had recurrent dislocation and 1 (3.5%) has had a subluxation event. Recurrent instability or the need for revision surgery is significantly greater when compared with those patients who have no evidence of postoperative instability.

Adult↗
PubMed2007

The cellular and molecular biology of periprosthetic osteolysis.

The generation of prosthetic implant wear after total joint arthroplasty is recognized as the major initiating event in development of periprosthetic osteolysis and aseptic loosening, the leading complication of this otherwise successful surgical procedure. We review current concepts of how wear debris causes osteolysis, and report ideas for prevention and treatment. Wear debris primarily targets macrophages and osteoclast precursor cells, although osteoblasts, fibroblasts, and lymphocytes also may be involved. Molecular responses include activation of MAP kinase pathways, transcription factors (including NFkappaB), and suppressors of cytokine signaling. This results in up-regulation of proinflammatory signaling and inhibition of the protective actions of antiosteoclastogenic cytokines such as interferon gamma. Strategies to reduce osteolysis by choosing bearing surface materials with reduced wear properties should be balanced by awareness that reducing particle size may increase biologic activity. There are no approved treatments for osteolysis despite the promise of therapeutic agents against proinflammatory mediators (such as tumor necrosis factor) and osteoclasts (bisphosphonates and molecules blocking receptor activator of NFkappaB ligand [RANKL] signaling) shown in animal models. Considerable efforts are underway to develop such therapies, to identify novel targets for therapeutic intervention, and to develop effective outcome measures.

Animals↗
PubMed2006

The role of constraint in total knee arthoplasty.

One of the keys to long-term success in total knee arthroplasty is knee joint stability. In most deformities, soft tissue asymmetry is present and can be corrected by soft tissue balancing techniques that allow the implant to tension the joint in flexion and extension symmetrically with resultant knee joint stability. Once this stability has been established, standard implants (PCL retaining or posterior stabilized types) may be used. If persistent laxity occurs despite soft tissue balancing, implants with greater constraint must be used. The constrained condylar types will improve stability and are useful particularly in the severe valgus knee with marked medial laxity or in revision procedures. If femoral bone is well preserved, constrained condylar knees may be used without stems. When there is marked bone loss and absent ligament support, a rotating-type hinge knee may be needed to restore bone deficits through augmentation and stabilization of the knee by the fixed axis nature of these designs.

Arthroplasty, Replacement, Knee↗
PubMed2006

Involvement of complement receptor 3 (CR3) and scavenger receptor in macrophage responses to wear debris.

The ability of prosthetic wear debris to induce pro-inflammatory responses in macrophages is widely appreciated, but little is known about the molecular mechanisms involved in particle recognition. Specifically, the nature of the cell surface receptors that interact with wear debris is poorly understood. Elucidating the identities of these receptors and how they interact with different types of wear debris are critical to understanding how wear debris initiates periprosthetic osteolysis. We examined the involvement of opsonization, complement receptor 3 (CR3), and scavenger receptor A (SRA), in responses to polymethylmethacrylate (PMMA) and titanium wear particles. Serum dependence of pro-inflammatory responses to PMMA and titanium was tested, and serum proteins that adhered to these two types of particles were identified. Several serum proteins, including known opsonins such as C3bi and fibronectin, adhered to PMMA but not titanium, and serum was required for pro-inflammatory signaling induced by PMMA, but not by titanium. Phagocytosis of PMMA and titanium by macrophages was demonstrated by flow cytometry. Blocking CR3 specifically inhibited phagocytosis of PMMA by macrophages, whereas blocking SRA specifically inhibited titanium uptake. Direct involvement of CR3 and SRA in cell-particle interaction was assessed by expression of these receptors in nonphagocytic HEK293 cells. CR3 specifically induced cell binding to PMMA particles and adhesion to PMMA-coated plates, while SRA specifically induced binding to titanium particles and adhesion to titanium-coated plates. Taken together, these results suggest involvement of opsonization, complement, and integrin receptors, including CR3 and fibronectin receptors, in PMMA action, and an involvement of scavenger receptors in responses to titanium.

Fibronectins↗
PubMed2006

Prevalence of infection in bilateral total hip arthroplasty: a comparison of single-stage 565 bilateral procedures performed with 1 or 2 sets of instruments.

Single-stage bilateral total hip arthroplasty can be performed with a completely new sterile setup for the second side or with the same instruments for both sides. The latter could theoretically lead to a higher prevalence of infection in the second side. We retrospectively determined the prevalence of deep infection during the first postoperative year in 271 consecutive patients operated on with different sterile setups (group 1) and 289 patients operated on with the same setup (group 2). There was one deep infection affecting the first side of a patient in group 1. In group 2, there were no deep infections (P is approximately 1.0) and one developed a superficial infection on the second side requiring readmission and intravenous antibiotics. Given the very low prevalence of deep infection of the first and second side (0.2% and 0%, respectively), it would be necessary to analyze more than 2,300 patients in each group to achieve statistical significance. Based on this experience, the use of the same set of instruments for the second side in the operating conditions described in this study appears safe.

Adult↗
PubMed2006

VenaFlow plus Lovenox vs VenaFlow plus aspirin for thromboembolic disease prophylaxis in total knee arthroplasty.

Two hundred seventy-five patients undergoing unilateral total knee arthroplasty were prospectively randomized to receive spinal epidural anesthesia (SEA), a VenaFlow calf compression device, and enoxaparin (group A) or SEA, VenaFlow, and aspirin (group B). Aspirin was started on the day of surgery, whereas enoxaparin was started 48 hours after surgery. Anticoagulants were continued for 4 weeks after surgery. All patients had an in-hospital ultrasound screening test on postoperative days 3 to 5 and a second follow-up ultrasound 4 to 6 weeks after surgery. The overall deep venous thrombosis rates in groups A and B were 14.1% and 17.8% (P = not significant), respectively. When used in combination with pneumatic compression devices and SEA, enoxaparin was not superior to aspirin in preventing deep venous thrombosis after total knee arthroplasty.

Adult↗
PubMed2006

Primary constrained condylar knee arthroplasty without stem extensions for the valgus knee.

UNLABELLED: Avoiding stem extensions in total knee arthroplasties may decrease operative time, prosthetic cost, and canal invasion at surgery. A constrained condylar knee implant without stem extensions also likely will be easier to revise and will eliminate the risk of end of stem pain. Our hypothesis was that a constrained condylar knee implant for primary severely deformed knees would show excellent midterm results with a low rate of aseptic loosening, even without diaphyseal-engaging stems. We retrospectively reviewed 70 consecutive primary constrained condylar knee implants without stem extensions from 1998 to 2001 in 61 patients with knees in 15 degrees valgus or greater. Forty-nine patients (55 knees) were followed up for 44.5 months (range, 2-6 years). Outcome was assessed using the Knee Society scoring system. Knee Society score and functional scores improved from 34 points and 40 points to 93 and 74 points, respectively. No radiographic loosening or wear was found. There were no peroneal nerve palsies, and no patients had flexion or medial instability. One patient was affected by chronic patellar dislocation. Constrained condylar knee implants in patients with severe valgus deformity resulted in pain relief and improved function, without substantial complications at midterm followup, without diaphyseal-engaging stem extensions. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗
PubMed2006

Venous thromboembolism is rare with a multimodal prophylaxis protocol after total hip arthroplasty.

UNLABELLED: We evaluated the safety and efficacy of a multimodal approach for prophylaxis of thromboembolism after total hip arthroplasty, which includes preoperative discontinuation of procoagulant medication; autologous blood donation; hypotensive epidural anesthesia; intravenous administration of heparin during surgery and before femoral preparation; aspiration of intramedullary contents; pneumatic compression; knee-high elastic stockings; and early mobilization and chemoprophylaxis for 4 to 6 weeks (aspirin 83%; warfarin 17%). One thousand nine hundred forty-seven consecutive, nonselected patients (2032 total hip arthroplasties) who received this multimodal prophylaxis were observed prospectively for 3 months. The incidence of asymptomatic deep vein thrombosis assessed by ultrasound in the first 171 patients was 6.4%. The incidence of clinical deep vein thrombosis in the subsequent 1776 patients was 2.5%. Symptomatic pulmonary embolism occurred in 0.6% (12 of 1947; nine in patients receiving aspirin and three in patients receiving Coumadin), none of them fatal. One patient died of a myocardial infarct. This multimodal approach is safe and efficacious and compares favorably with those reported in the literature and with our historic controls. If these preventive measures are strictly observed during the perioperative period, postoperative chemoprophylaxis does not need to be aggressive in the patient without predisposing factors. Our low rate of deep vein thrombosis and pulmonary embolism do not support routine anticoagulation prophylaxis with drugs that increase risk of bleeding. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Adolescent↗
PubMed2006

Perioperative morbidity after single-stage bilateral total hip arthroplasty: a matched control study.

We asked whether the perioperative morbidity and mortality of patients having bilateral single-stage total hip arthroplasties would be increased. We retrospectively compared 400 patients who had bilateral total hip replacements with a matched group of 400 patients who had unilateral total hip replacements. Patients were matched according to age (+/- 1 year), gender, American Society of Anesthesiologists (ASA) classification, body mass index (+/- 4 kg/m), and diagnosis (osteoarthritis, 81.2%). There were no deaths in either group. The group of patients who had bilateral total hip arthroplasties had a greater number of minor complications per hip (0.34 +/- 0.6 versus 0.25 +/- 0.6) but only a trend toward an increased number of major complications per hip (0.037 +/- 0.2 versus 0.015 +/- 0.1). Patients who had bilateral total hip arthroplasties had a trend toward increased risk of dislocation (1.6%/hip versus 0.5%/hip). The patients in this group also had increased number of fat emboli syndrome per surgically treated hip (0.015 versus 0.0025). Based on a calculation per surgically treated hip, patients who had bilateral total hip arthroplasties had a similar percentage of blood transfusions (1.2 versus 0.9/hip), but more patients received allogeneic blood (23% versus 3.8%). The ASA classification was the only independent predictor for minor complications, major complications, and fat emboli syndrome. We think bilateral single-stage total hip arthroplasties have an acceptable perioperative risk for patients with ASA Class 1 or 2 physical status.

Adult↗
PubMed2006

A new patellofemoral scoring system for total knee arthroplasty.

Patellofemoral complications after total knee arthroplasty (TKA) can result in substantial dissatisfaction with the procedure for some patients. In assessing outcomes of TKA, however, there is often a discrepancy between patellofemoral symptoms and the results obtained by conventional scoring and radiographic analysis. We asked whether a new scoring system and weightbearing radiographic view would more accurately represent patellofemoral kinematics and explain related complications. Sixty-nine patients (100 knees) who underwent posterior-stabilized TKA between 1994 and 1997 were included for clinical and radiographic evaluation. A new patella score was developed to rapidly determine complications, ranged from 0 to 100 points, and included ratings for subjective and objective aspects of TKA. A new weight-bearing axial radiographic view was devised by positioning the standing patient in a semisquatted position. Measurements for patella alignment (tilt and subluxation) were performed. Preoperative Knee Society knee and function scores were 43 +/- 5 points, and 39 +/- 15 points, respectively. Postoperatively, scores increased to 93 +/- 8 and 89 +/- 8 points, respectively. The patella score averaged 89 +/- 8 points and showed satisfactory interobserver variability. The new weightbearing radiographic view demonstrated sources of patellofemoral symptoms. We report a new scoring system and weightbearing view that are easy to use and more accurately represent patellofemoral kinematics than do conventional methods of analysis.

Arthroplasty, Replacement, Knee↗
PubMed2006

Wear debris inhibition of anti-osteoclastogenic signaling by interleukin-6 and interferon-gamma. Mechanistic insights and implications for periprosthetic osteolysis.

BACKGROUND: Wear debris challenge of macrophages provokes the generation of proinflammatory cytokines, which contribute to periprosthetic osteolysis. However, it is not known whether this effect is accompanied by reprogramming of other cytokines present within the periprosthetic tissue that may be involved in anti-osteoclastogenic activities. In the present study, we examined the ability of wear debris particles to inhibit the signaling of two such cytokines, interleukin-6 and interferon-gamma. METHODS: Human osteoclast precursor cells were challenged with particles of titanium or polymethylmethacrylate bone cement prior to the addition of the cytokines interleukin-6 or interferon-gamma. Interleukin-6 signaling was determined by measuring the activation of STAT3 signal transduction with use of immunoblotting and electrophoretic mobility shift assays. Interferon-gamma signaling was determined by measuring the activation of STAT1 with use of immunoblotting and electrophoretic mobility shift assays and by measuring the expression of interferon-gamma-inducible genes with use of real-time reverse transcription-polymerase chain reaction assays. Involvement of mitogen-activated protein kinases in cytokine signaling was assessed by including mitogen-activated protein kinase inhibitors in these assays and also by means of immunoblot assessment of mitogen-activated protein kinase activation by wear debris particles. Wear debris modulation of expression of the cytokine suppressors SOCS1 and SOCS3 (as well as pro-inflammatory mediators) was assessed with use of real-time reverse transcription-polymerase chain reaction assays. RESULTS: Both titanium and polymethylmethacrylate particles potently inhibited interleukin-6-induced STAT3 activation in human osteoclast precursor cells. Inhibition of p38 mitogen-activated protein kinase, which is activated by titanium and polymethylmethacrylate, reversed the inhibitory effects of these particles on interleukin-6 signaling, whereas inhibition of ERK and JNK mitogen-activated protein kinases (which are also activated by both types of wear debris) had no effect. Titanium and polymethylmethacrylate also both induced expression of SOCS3, an inhibitor of interleukin-6 signaling. In addition to its effects on interleukin-6 signaling, titanium also profoundly inhibited the interferon-gamma-induced activation of STAT1 and the expression of interferon-gamma-inducible genes, whereas polymethylmethacrylate had no effect on interferon-gamma signaling. CONCLUSIONS: Titanium inhibits both interferon-gamma and interleukin-6 signaling in human osteoclast precursor cells, whereas polymethylmethacrylate bone cement inhibits only the latter. Wear particle inhibition of interleukin-6 specifically involves the activation of p38 mitogen-activated protein kinase and is accompanied by substantial induction of SOCS3, an inhibitor of interleukin-6 signaling. In contrast, titanium inhibition of interferon-gamma signaling is not dependent on mitogen-activated protein kinase activation and is accompanied by only modest induction of the interferon-gamma inhibitor SOCS1.

Bone Cements↗
PubMed2006

Minimally invasive total hip replacement: the posterolateral approach.

Our experience with the posterolateral mini-incision technique over the last 8 years has shown that total hip arthroplasty can be performed safely and effectively in properly selected patients through a much smaller incision than the one traditionally used. The main advantage of the posterolateral approach compared with other mini-incisions is its simplicity, with shortened operating time as a result. While the surgical time for a posterior approach is an average of 37 to 70 minutes throughout the literature, the 2-incision approach prolongs the surgery by a factor of 2 or 3. Compared with the anterior or 2-incision approach, the posterolateral and anterolateral approaches also have a much lower incidence of perioperative complications, with the rate being similar to rates seen with a standard incision. For the 2-incision technique and the anterior mini-incision approach, perioperative periprosthetic fracture rates of up to 8.7% and 8.4%, respectively, have been described. Surgeons who traditionally used an anterolateral standard approach might prefer an anterolateral mini-incision. The anterolateral mini-incision total hip arthroplasty has demonstrated excellent results; in the past it was suggested that the anterolateral approach has a higher incidence of heterotopic bone formation and impaired early abductor function, but more recent studies show no difference in abductor strength and limping between the anterolateral and posterior approaches. On the other hand, the posterior approach has been associated with an increased risk of postoperative dislocations. We did not encounter an increased incidence of postoperative dislocation at our institution. This might be related to the routine repair of the external rotators and the capsule in all patients. In summary, both the anterolateral and the posterior mini-incision approaches are reasonable alternatives, and surgeons should choose the approach that they feel most comfortable with. Statements in the press and by some members of the orthopedic community suggest that a smaller incision has revolutionized total hip replacement by accelerating the recovery and improving the functional outcome, but most articles in the peer-reviewed literature fail to confirm these hypotheses. Considering that mini-incision total hip replacement has no dramatic clinical benefits other than the cosmetic appeal, the use of mini-incision total hip replacement by the average orthopedic surgeon should be carefully monitored. In the meantime, the patient should be informed about the true merits of the technique, and any marketing that misleads patients' perception of the technique should be avoided. Because the mini-incision leads to results similar to those obtained with the standard approach, we will, encouraged by the enthusiasm of our patients, continue to use this approach.

Arthroplasty, Replacement, Hip↗
PubMed2006

Minimally invasive total hip arthroplasty: the posterior approach.

Minimally invasive total hip replacement is probably a misnomer and the procedure is better termed less invasive total hip replacement. The mini-posterior approach is a modification of a standard approach, with a smaller skin incision and less deep tissue dissection. The gluteus maximus tendon is not released and the quadratus femoris muscle is minimally violated. Blood loss has been documented to be less and early recovery is facilitated. Compared with the standard posterior approach, there have been fewer complications associated with the modified approach.

Arthroplasty, Replacement, Hip↗