Faculty Bibliography

Ochronosis commonly affects all connective tissue. Recognition of changes secondary to the deposition of ochronotic pigments has increased with advances in diagnostic technology, allowing both improved imaging and early biochemical and genetics-based diagnosis of alkaptonuria, the cause of ochronosis. Successful symptomatic treatment of ochronotic arthropathy with joint replacement has been documented, and a new pharmacotherapeutic agent, nitisinone, is currently under investigation for both prevention and treatment of ochronosis. This review of the literature highlights recently recognized complications, new diagnostic techniques, and treatment options.

Dislocation is one of the most common complications after total hip arthroplasty (THA). Risk factors include neuromuscular and cognitive disorders, patient non-compliance, and previous hip surgery. Surgical considerations that must be addressed include approach, soft-tissue tension, component positioning, impingement, head size, acetabular liner profile, and surgeon experience. Recent improvements in posterior soft-tissue repair after primary THA have shown a reduced incidence of dislocation. When dislocation occurs, a thorough history, physical examination, and radiographic assessment help in choosing the proper intervention. Closed reduction usually is possible, and nonsurgical management frequently succeeds in preventing recurrence. When these measures fail, first-line revision options should target the underlying etiology. This most often involves tensioning or augmentation of soft tissues, as in capsulorrhaphy or trochanteric advancement; correction of malpositioned components; or improving the head-to-neck ratio. If instability persists, or if a primary THA repeatedly dislocates without a clear cause, a constrained cup or bipolar femoral prosthesis may be as effective as a salvage procedure.

For this study, 100 total hip arthroplasties (THAs) in a transtrochanteric approach group and 100 THAs in a posterolateral approach group were performed at one university hospital by a single, experienced surgeon. These THAs were then followed up for a minimum of 2 years to determine the incidence of postoperative complications. In our study, patients undergoing primary THA by the posterolateral approach were 18.4 times more likely to be complication free than patients in whom the transtrochanteric approach was used. This benefit, combined with a shortened surgical time, decreased blood loss, and technical ease, shows the advantages of the posterolateral approach for THA.

The identification of factors that may affect the eventual survivorship of primary total hip arthroplasty is essential. The surgeon needs this information to assist in the patient selection process and to mold patient expectations. Patients may then be counseled regarding factors within their control, and this information may affect long-term behavior. For a given patient, how might the surgeon best advise that person to prolong the longevity and functionality of his or her hip replacement?

Surgical exposure of the hip for trauma, infection, or reconstruction can be adequately accomplished through a variety of surgical approaches. This article describes in detail five classic approaches to the hip: Smith-Petersen (anterior), Watson-Jones (anterolateral), Hardinge (direct lateral), transtrochanteric, and posterolateral. In addition, recently described mini-incision posterior and anterior approaches are outlined.

Clinical results from the past 30 years have proven total hip arthroplasty (THA) to be an effective technique for treating arthritic and degenerative conditions of the hip. Though there is little question concerning the effectiveness THA in general, significant debate exists concerning the best technique for performing the procedure. Sir John Chamley's concept of low-friction arthroplasty (LFA), considered to be the gold standard for THA, employs a cemented fixation technique for both the femoral and acetabular components. Over time, the merits of cemented fixation have been called into question as significant percentages of LFA implants failed and required revision surgery. Hybrid total hip arthroplasty is a variation of LFA that employs cemented fixation of the femoral component with cementless fixation of the acetabular component. Intermediate-term clinical results of hybrid THA have shown it to be a promising technique, with revision rates of both the femoral and acetabular components superior to Chanley LFA studies at similar lengths of follow-up. Though these results are encouraging, long-term data from the hybrid THA studies are required before a conclusion can be made as to whether the hybrid method is in fact superior to the LFA technique for performing THA.

Total hip arthroplasty is characterized by significant blood loss. The principal aim of blood management in joint replacement surgery is to minimize both the risks associated with surgical blood loss and the risks associated with allogenic blood transfusion. In the 1980s, the AIDS epidemic triggered the development of a variety of innovative approaches to conserving blood and reducing the need for allogenic transfusion to replace surgical blood loss. Subsequently, the safety of the blood supply was dramatically improved, changes in surgical technique led to decreased surgical blood loss, and changes in transfusion thresholds made the need for transfusion less common. The review re-examines the options available for the management of blood loss in total joint replacement and defines parameters that can be used preoperatively to predict which patients are likely to benefit from these interventions, given the clinical realities of the 21st century.

The purpose of this prospective randomized clinical study was to investigate the enhanced systemic fibrinolysis mechanism of venous thrombosis prevention by pneumatic compression after total hip arthroplasty. Fifty patients were randomized into one of two groups (one with pneumatic compression [n=25] and one without [n=25]). Blood was drawn from a radial arterial line immediately preoperatively (baseline), at skin closure, and 8 hours and 22 hours after the baseline sample. Serum determinations of antigen of tissue plasminogen activator and plasminogen activator inhibitor-1 were done using enzyme-linked immunosorbent assays. These data do not support the enhancement of systemic fibrinolysis mechanism for lowering thromboembolic risk after total hip arthroplasty by pneumatic compression devices. The results of this study showed no differences that were statistically significant between the two groups. The greatest difference was observed 8 hours after surgery for the plasminogen activator inhibitor-1 marker, (28.12 with compression versus 22.07 ng/mL without); however, this result was not statistically significant. The beneficial effect of mechanical compression is more likely achieved through increased flow, local fibrinolytic effects, or both.

The number of single-stage bilateral total hip arthroplasties done each year is increasing. The risk of postoperative complications in medically stable patients is acceptable; complications are approximately 1.3 times more frequent than with unilateral total hip arthroplasty. Although there are no absolute indications for a single-stage bilateral total hip arthroplasty, the procedure is usually contraindicated in patients with such comorbidities as heart disease, pulmonary insufficiency, or diabetes, and it is absolutely contraindicated in patients with a documented patent ductus arteriosus or septal defect. The primary postoperative concern is that the cardiopulmonary insult associated with two surgical wounds and surgeries can lead to an increase in thromboembolic events. The cost for single-stage bilateral total arthroplasty is less than that for a two-stage bilateral total hip arthroplasty, with savings predominantly due to reduced length of acute hospital stay. However, the decision to undergo single-stage bilateral total hip arthroplasty is one that must be made in concert with the patient.

The mean pore size and percent porosity of vacuum-mixed cement were compared with centrifuged cement and cement hand mixed by skilled specialized operating room technicians. Centrifuged cement samples had the smallest mean pore size when compared with vacuum-mixed specimens. The mean pore size for the hand-mixed specimens was intermediate and not significantly different from the other 2 mixing techniques. Results were reversed, however, for mean percent porosity. Centrifuged cement had the highest percent porosity; vacuum-mixed cement, the lowest; and hand-mixed cement, intermediate. The porosity of vacuum-mixed Simplex P (Howmedica, Rutherford, NJ) bone-cement was similar from the initial to the remnant cement extruded from the cement gun. There was no reduced cement porosity with vacuum mixing or centrifugation as anticipated. Reversion to hand mixing by highly skilled technicians could result in a significant cost savings without negative effects on cement porosity.