Cemented total hip arthroplasty with Boneloc bone cement

Boneloc cement (WK-345, Biomet Inc, Warsaw, Ind) attempted to improve cement characteristics by reducing exotherm during polymerization, lowering residual monomer and solubility, raising molecular weight, and lowering airborne monomer and aromatic amines. To study the efficacy of this cement, a selected group of 20 patients were prospectively enrolled and followed up after hip arthroplasty. All components were cemented. During the enrollment period, approximately 70 other hip arthroplasties were performed. Clinical evaluation was based on the Harris hip score. Radiographic evaluation was based on assessment of position of the components, subsidence, and/or presence of radiolucencies. Patients had follow-up for an average of 42 months (11 to 58 months); 1 was lost to follow-up. Of these, 7 (35%) had failure at last follow-up. Despite its initial promise, Boneloc cement had an unacceptably high failure rate over a relatively short follow-up period and is not recommended for use. Despite the longevity and odor toxicity problems with conventional bone cement, new cement technologies must be approached with caution.

Fatal pulmonary embolus after shoulder arthroplasty

Pulmonary embolus after upper-extremity surgery is a rare complication of upper extremity surgery. A case of a fatal pulmonary embolus after shoulder arthroplasty is reported. The embolus originated from a lower-extremity deep venous thrombosis. The cause of the deep venous thrombosis and subsequent pulmonary embolus was attributed to prolonged immobilization in the perioperative period.

Upper extremity deep venous thrombosis leading to pulmonary embolism after total hip arthroplasty

Upper extremity deep venous thrombosis most commonly occurs secondary to the presence of subclavian central venous catheters. Of all upper extremity deep venous thromboses, 12% may cause pulmonary embolism; however, pulmonary embolism from a so-called primary thrombosis is uncommon. We report an unusual case of pulmonary embolism after primary deep venous thrombosis in the down arm after total hip arthroplasty.

Biomechanical analysis of supracondylar femoral fractures fixed with modern retrograde intramedullary nails

OBJECTIVES

Several new retrograde supracondylar intramedullary nails have been developed to specifically address fractures of the distal femur. The nails appear clinically effective, but there are few biomechanical data documenting the stability of the fixation or the mechanical stiffness of the different designs. The goal of this study was to assess the torsional and bending stiffness of four designs of intramedullary nails developed for this application.

METHODS

Four nail designs were tested in torsion and bending to determine system stiffness: Ace supracondylar, Richards "five hole" and "multi-hole" supracondylar, and Biomet retrograde. The nails were inserted into cadaveric femurs in which a one-centimeter distraction osteotomy had been created seven centimeters proximal to the condyles. The constructs were then tested on an Instron biaxial testing system.

RESULTS

There were no statistically significant differences in bending stiffness among the groups of nails (range 0.79 to 1.18 newtons/meter; p > 0.1). However, the Ace nails (1.10 newtonmeters/degree) did exhibit a statistically lower torsional stiffness compared with the other nails (2.20 to 2.21 newton-meters/ degree; p < 0. 1). No differences were noted as a function of the number of locking holes.

CONCLUSIONS

The bending stiffness of four currently available designs of retrograde intramedullary nails does not appear to be dependent on design variations. The torsional stiffness did vary among the four designs, but this was not determined by the number of fixation holes provided. It appears that a well-placed retrograde supracondylar nail of modern design should have sufficient stiffness to support the femur and provide stability during fracture healing.

Geriatric intertrochanteric hip fractures: an economic analysis

Hip fractures have a high economic and social cost to society. Rising healthcare costs, coupled with managed healthcare systems, have forced a close inspection of healthcare expenditures. To evaluate the impact of geriatric intertrochanteric hip fractures upon a hospital system, an economic cost-analysis was undertaken. An analysis was made of financial and hospital data of elderly patients who sustained an intertrochanteric hip fracture and subsequently underwent open reduction and internal fixation. Increasing patient age did not correlate with length of stay, overall hospital cost, or net hospital income. When costs were subdivided, there were no statistically significant differences relative to patient age for costs of pharmacy, radiology, respiratory therapy, or operating room supply. There were, however, statistically significant correlations between patient age and costs of the operating room, blood, and anesthesia. During the 36-month study period, a case manager was added to the orthopedic surgical team. There was a trend toward decreased length of stay after the addition of the case manager, but the overall cost of patient care was not affected.

Inexpensive methods of repairing cortical defects in cemented total joint replacement

Inexpensive methods to augment cement pressurization in the face of cortical defects are presented. The first two methods involve the use of disposable plastic syringes and the foil packaging from suture material. The third uses screws that were removed with hardware. The techniques prevent cement extrusion from the cortical defects with minimal stripping of the remaining soft tissues. Methods for using foil packaging to form templates for accurate production of well-fitting cortical inlay grafts and the use of plastic wire ties as temporary fixation devices are also described.

Analysis of lower extremity embolic material after total knee arthroplasty in a canine model

Emboli assumed to consist of fat, marrow, cement, and bone are generated during total knee arthroplasty. This study collected and identified the constituents of the embolic debris and assessed the effects of intramedullary cutting guides in a canine model. During cemented knee arthroplasties with or without the use of intramedullary guides, all embolic debris was collected in a single lobe of lung. In dogs using intramedullary guides, transesophageal echocardiography revealed a sustained embolic shower, and histologically marked amounts of emboli obstructed the pulmonary vasculature. The emboli were composed of fat cells and hematopoietic cells (marrow elements) interspersed with free fat globules. Marrow elements are the primary constituents of the emboli generated during total knee arthroplasty. Intramedullary guides increased debris generation.

Effect of epidural analgesia on venous blood flow after hip arthroplasty

The effects of postoperative epidural infusions using local anesthetic and narcotic were assessed in reference to lower extremity blood flow. Nineteen patients who underwent unilateral total hip arthroplasty were randomly assigned to receive a postoperative epidural infusion of either 5 microg/ml fentanyl or 5 microg/ml fentanyl plus 0.125% bupivacaine at a rate of 10 ml per hour. The infusions were started after complete resolution of the operative epidural blockade. Femoral venous blood flow volume and velocity were measured above and below the saphenous vein bifurcation using an Acuson #128XP/10 computed sonography system (duplex ultrasound) and proprietary software. Femoral venous blood flow was not affected by the type of infusion and did not increase during the study period. However, femoral venous blood flow volume increased 50% after active flexion and extension of the foot, 10 times in quick succession. The addition of bupivacaine (a local anesthetic that blocks sympathetic afferent nerves) to a postoperative epidural infusion does not augment blood flow from the deep veins of the leg after total hip arthroplasty. Alternatively, lower extremity skeletal muscle activity significantly enhances femoral venous blood flow and may be a useful adjunct in deep venous thrombosis prevention.

Arthroscopic treatment of peripatellar fibrosis after total knee arthroplasty

Forty-eight total knee arthroplasties (42 patients) were treated arthroscopically for symptomatic peripatellar fibrosis. All patients complained of knee pain before surgery. In addition, 47 knees (98%) had clicking or clunking, 35 (73%) had difficulty climbing stairs, and 9 (19%) had motion problems. The results of arthroscopy were 20 good (42%), 9 fair (19%), and 19 poor (40%). The mean follow-up time was 32.8 months (range, 11-75 months). A fourth portal was required in 20 knees (17 patients, 42%), indicating the complexity and difficulty of debridement. No components were found to be loose at the time of arthroscopy. A constellation of symptoms are caused by peripatellar fibrosis. In contrast to past reports, the arthroscopic treatment of peripatellar fibrosis was found to be unpredictable. Debridement of the offending soft tissue did not necessarily guarantee a good result. Arthroscopic management of peripatellar fibrosis is recommended; however, limited and specific surgical goals should be established prior to intervention.

Core decompression for osteonecrosis of the femoral head

A retrospective++ review of core decompression of the femoral head for treatment of osteonecrosis was done. Cause of osteonecrosis, radiographic stage and progression, complications, and clinical results were evaluated. The study was based on 54 hips in 45 patients (98.2% followup rate). All patients reported pain preoperatively. Thirty-five hips (30 patients) were considered to have failed. Of these, 26 hips (23 patients) underwent total hip arthroplasty. The remaining 9 hips (7 patients) had little or no relief of pain and no improvement in function, but had not undergone total hip arthroplasty at last followup. The average time to failure was 11.1 months (2-34 months). Nineteen hips (16 patients) were considered successful. Fifteen hips (12 patients) were graded good to excellent and 4 hips (4 patients) were graded fair in terms of clinical results with an average followup of 47.5 months (12.4-95.7 months). The mean preoperative Hospital for Special Surgery hip score improved from 24.6 points (range, 18-38 points) to 34.2 points (range, 20-40 points). There were 2 intertrochanteric femur fractures in this group (5 and 6 weeks postoperatively). The overall success rate of core decompression in this series was 35.2% (19 of 54 hips, 45 patients). The results of core decompression in this study were poor in general and had an unpredictable effect on disease progression.

Use of cemented all-polyethylene and metal-backed acetabular components in total hip arthroplasty. A comparative study

The results of 115 primary total hip arthroplasties (97 patients) performed using the Charnley system and contemporary cementing techniques were reviewed. Fifty-five all-polyethylene cups and 60 metal-backed cups were used. The mean follow-up period was 84 months. No statistically significant difference was noted between groups for radiographic loosening and no cup has been revised to date. Survival analysis did not reveal a statistically significant difference between groups. Although all-polyethylene cups had significantly greater polyethylene thickness, no difference was noted for rate of wear. Increased loosening of the metal-backed cups was not observed. Polyethylene thickness is increased by the use of 22-mm heads and this may have accounted for the lack of difference in loosening rates of the all-polyethylene and metal-backed cups.

A comparison study of treatment of thoracolumbar fractures using the ACE Posterior Segmental Fixator and Cotrel-Dubousset instrumentation

The results of 26 consecutive thoracolumbar fractures treated with Cotrel-Dubousset instrumentation (CDI) (n = 12) or the ACE Posterior Segmental Fixator (n = 14) with a mean follow up of 20.2 months were analyzed. Preoperatively, no statistically significant difference was noted between the two treatment groups. Postoperatively, no statistically significant difference was noted for improvement of kyphosis (mean: -6.00 degrees ACE, 1.92 degrees CDI), vertebral body height (mean: 17.86% ACE, 18.83% CDI), vertebral body angle (mean: -6.21 degrees ACE, -5.42 degrees CDI), or estimated blood loss (mean: 1544 cc ACE, 1620 cc CDI). All patients with incomplete paraplegia improved by at least one Frankel grade. Statistically significant differences were noted in operative time (mean: 269 minutes ACE, 357 minutes CDI, P < .0005), and in the number of instrumented levels (mean: 3 ACE, 5.8 CDI). All patients exhibited solid fusion radiographically. Thoracolumbar fractures can be effectively treated by either CDI or the ACE Fixator. The ACE Fixator has the advantage of sparing motion segments and decreased operative time.

Percutaneous intramedullary pinning of proximal humeral fractures

Proximal humeral fractures can usually be treated closed. However, even with an adequate closed reduction, these fractures are occasionally unstable, fail to remain reduced, and require operative intervention. A percutaneous intramedullary pinning technique is effective in stabilizing these fractures. Two cases that illustrate the adult and pediatric techniques for pin placement/application are presented. In the pediatric population, however, large multiple pins often cannot be used due to the size of the intramedullary canal, and fewer or smaller diameter pins are used.

Appropriate techniques for musculoskeletal tumor biopsy

Despite the crucial nature of a biopsy for the diagnosis and treatment of a musculoskeletal tumor, the basic tenets of biopsy technique are frequently not respected. Unfortunately, catastrophic errors in biopsy technique occur frequently. Examples of the more common errors and the correct surgical techniques are discussed.

A case of traumatic spino-pelvic dissociation

A case of traumatic spino-pelvic dissociation is reported. The unusual fracture pattern (grade III-B open left sacroiliac joint fracture dislocation, Denis type I longitudinal right sacral fracture, transverse sacral fracture at the S3-4 level, and a left comminuted pelvic wing fracture) led to a complete dislocation of the spine from the pelvis, transection of the left S1 and S2 nerve roots, and intrusion of the cranial portion of the spine into the pelvis. The patient underwent open reduction internal fixation of the spine and the pelvis in combination with general surgical management. Two years postinjury, the patient lives independently and walks with one cane.

Simple surgical techniques to protect the soft tissues during total knee arthroplasty

The surgical techniques involved in total knee arthroplasty are often overshadowed by implant design, metallurgy, and fixation methods. This is especially true when considering the handling of the soft tissues rather than the bony cuts. The authors believe that protection of the soft-tissue structures around the knee is of paramount importance and describe six surgical techniques that they use to accomplish this during total knee arthroplasty.

Technical tips for the fixation of supracondylar femur fractures with the sliding screw-plate device

Supracondylar fractures of the femur are common injuries. When open reduction and internal fixation are required, these fractures become challenging problems. We present four technical tips that help the surgeon obtain good results when open reduction and internal fixation with the screw- and side-plate device are chosen.