Hip arthroplasty with a collared straight cobalt-chrome femoral stem using second-generation cementing technique: a 10-year-average follow-up study.

Clinical and radiographic results of 116 patients who had undergone 132 hip arthroplasties at our institution from 1983 to 1988 with a collared cemented straight cobalt-chrome femoral stem using second-generation cementing technique were reviewed. Twenty hips in 20 patients who were part of the original cohort were lost to follow-up. Mean age at the time of surgery was 68.2 years. Mean radiographic follow-up was 9.6 years with a minimum follow-up of 5 years. Ten-year survivorship of the component was 96.5% with revision considered as an endpoint and 94.2% with either revision or radiographic loosening considered the endpoint. Three implants (2.3%) were revised for aseptic loosening at a mean of 8.1 years after implantation. One implant (0.8%) was revised for septic loosening at 10.5 years after surgery. Of the implants not revised, 1 showed evidence of circumferential bone-cement radiolucencies, and 1 had radiolucencies at the implant-cement interface. Five of the surviving femoral components (5.0%) showed focal areas of cystic osteolysis, and proximal femoral bone resorption under the collar was seen in 32 patients (31.7%). There were no cases of cement fracture or stem subsidence. The biomechanical and material properties of this stem combined with second-generation cementing technique look promising for long-term survivorship.

Wear rates of ceramic-on-ceramic bearing surfaces in total hip implants: a 12-year follow-up study.

A retrospective clinical and radiographic analysis was performed on 58 patients (60 hips; mean age at time of surgery, 45.2 years) at a minimum of 10-year follow-up (mean, 12.7 years) after total hip replacement using a ceramic-on-ceramic hearing total hip implant (Autophor, Smith and Nephew, Memphis, TN). Mean wear rate at final follow-up was 0.21 mim, averaging 0.016 mm/y. There were no cases of periprosthetic osteolysis in the acetabuulum or femur. For the unrevised components, there were 3 (5%) cases of protrusio acetabuli and 4 (7%) cases of acetabular component loosening. On the femoral side, 78.3% had distal pedestal formation, and 83% had greater than 2 mm implant-bone radiolucencies in more than 5 Gruen zones as a result of gross motion of the stem. Despite radiographic evidence of implant loosening, this hard bearing articulation functioned well in vivo for more than 12 years with remarkably low wear--approximately one tenth the rate reported for metal-on-polyethylene total hip bearings.

Stress fractures of the femoral neck.

Stress fractures of the femoral neck are uncommon injuries. In general these injuries are seen in two distinct populations: (1) young, healthy, active individuals such as recreational runners, endurance athletes, or military recruits; and (2) the elderly who have osteoporosis. Stress fractures can be classified as either fatigue or insufficiency fractures and result from untoward cyclic loading or impaired bone quality. The key to treatment is early diagnosis, which may require scintigraphy or magnetic resonance imaging. Nondisplaced compression type stress fractures can be treated nonoperatively with protected weight-bearing and frequent radiographic followup. Tension type stress fractures should be stabilized internally to prevent the adverse consequences of fracture displacement.

Results of cemented metal-backed acetabular components: a 10-year-average follow-up study.

The clinical and radiographic results of 86 primary total hip arthroplasties performed in 74 patients from 1983 to 1987 with a cemented metal-backed acetabular component and a cemented collared straight femoral stem with a 32-mm head were reviewed at a mean follow-up of 10.1 years. Seven patients (9.2%) underwent acetabular component revision at a mean of 9.0 years after implantation; an additional 24 components (31.6%) demonstrated evidence of radiographic loosening, resulting in a total failure rate of 40.8%. Periacetabular radiolucencies were noted in Charnley zones at the following rates: 34.2% in zone I, 18.4% in zone II, and 27.6% in zone III. In addition, 18.4% and 38.2% of implants demonstrated evidence of migration and excessive polyethylene wear. Excessively vertical cup placement (>49 degrees inclination) at the time of initial arthroplasty was statistically correlated with polyethylene wear, implant migration, and fixation failure. A trend of increasing implant failure was also noted with decreasing polyethylene liner thickness. Periacetabular cement mantle thickness was not statistically correlated with subsequent component loosening or failure. Results of Kaplan-Meier survivorship analysis using revision as an endpoint showed 93.6% survivorship at 10 years and 88.4% at 12 years. The mean modified Harris hip scores were 46.9 preoperatively and 81.8 at final follow-up. The significant overall rates of radiographic loosening, migration, polyethylene wear, and implant revision confirm the suspected trend of increasing failure rates of cemented metal-backed acetabular components over time.

Results of prescription use of pulse ultrasound therapy in fracture management.

As of October 17, 1994,a pulsed ultrasound device has been used on a prescription basis by orthopaedic surgeons in the United States (Fig. 1). The Food and Drug Administration released this device for use in fresh tibial diaphysis and fresh distal radial metaphysis fractures. A patient registry that records all clinical data concerning both on-label and off-label prescription use of ultrasound, including other bones and different durations of fracture age, has been analyzed, Table 1 summarizes the data from October 17, 1994 to July 14, 1997. The overall healing rate was 91.6%. This includes fresh, delayed, and nonunited fractures.

Current concepts in intramedullary nailing.

The past decade has seen a dramatic increase in the use of intramedullary nailing for fracture manage- ment. Increased availability of new techniques and instrumentation have contributed to the continuing expansion of applications for intramedullary nailing. The introduction and availability of image intensi- fiers into American hospitals has also led to the popularization of closed intramedullary nailing techniques, and locking nails have expanded the indications of closed intramedullary nailing to unstable long bone frac- tures of the femur, tibia, and humerus. New classes of nails such as the second generation Reconstruction Nail have expanded the use of intramedullary nailing for more proximal femoral fractures. In addition, advances in biomechanical and locking designs have recently led to the use of intramedullary nailing in distal femur fractures and forearm fractures. There is continuing evolution of specialized nails including a self-guiding nail, nails for use in femoral lengthening, and nails used in conjunction with intramedullary osteotomies.

Postoperative complications and mortality associated with operative delay in older patients who have a fracture of the hip.

We prospectively studied 367 patients who had a fracture of the hip, to determine the effect of an operative delay on postoperative complications and on the one-year mortality rate. All of the patients were at least sixty-five years old, cognitively intact, living at home, and able to walk before the fracture. An operative delay was defined as an interval of three calendar days or more between the time of admission to the hospital and the operation. The operation was performed within two calendar days after admission in 267 (73 per cent) of the patients. When the factors of the patient's age and sex and the number of pre-existing medical conditions were controlled, it was found that an operative delay beyond this period approximately doubled the risk of the patient dying before the end of the first postoperative year. When the patient's age and sex and the severity of pre-existing medical conditions were controlled, there was also an increase in mortality associated with an operative delay, although this was not significant. With the numbers studied, an operative delay beyond two calendar days did not have a significant effect on the prevalence of complications during hospitalization. We concluded that an operative delay of more than two calendar days after admission is an important predictor of mortality within one year for elderly patients who have a fracture of the hip and who are cognitively intact, able to walk, and living at home before the fracture. Optimally, such patients should have the operation within two calendar days after admission to the hospital.

Posttraumatic nonunion of the distal tibial metaphysis. Treatment using the Ilizarov circular external fixator.

Ten nonunions of the distal tibial metaphysis were treated by using the Ilizarov circular external fixator. Original fractures were classified in terms of the Association for the Study of Internal Fixation as AO type A (4 cases), type B (5 cases), and type C (1 case). Six patients had a history of osteomyelitis. Bifocal compression-distraction lengthening osteosynthesis was performed in all cases. Proximal metaphyseal corticotomy was combined with resection and compression of the distal nonunion site in five cases, and compression alone in three patients. Ankle arthrodesis, in addition to nonunion resection, was performed in two patients. Follow-up averaged 48 months (range, 26 to 81). Eight nonunions healed (80%). Limb length was completely corrected in five cases; angular and rotational alignment was corrected to within 5 degrees in seven patients (70%). Based on an objective and subjective scale, the results were considered good-to-excellent in seven cases and poor in three. Despite the high complication rate and relatively low success rate (70%), the use of the circular frame with small-diameter, tensioned wires may provide an alternative method for the treatment of the very difficult problems associated with complex low distal tibial metaphyseal nonunions.

The effectiveness of a hospital-based strategy to reduce the cost of total joint implants.

Our hospital implemented an integrated cost-containment program designed to address the increasing disparity between the cost of orthopaedic implants used for total joint replacements and the amount of hospital reimbursement provided for these procedures. This program was divided into four phases: (1) the analysis of the specific usage of total hip and total knee implants at our institution, (2) the development of surgeons' awareness of the problem and the enlistment of their participation in the process of cost containment, (3) the initiation of a competitive bidding system to select standard prostheses that would be available for general use within the institution, and (4) the establishment of a prosthesis-utilization committee to monitor the process and to make decisions concerning the use of non-standard prostheses. Using this cost-containment program, our hospital greatly reduced the number of vendors and implant systems used; all implants were purchased on a consignment basis, which minimized the cost of implant inventory. The average cost reductions in the first year were 14 per cent for total hip implants and 24 per cent for total knee implants. Over-all implant costs were reduced by an estimated $706,477, or 23 per cent of the budget for implants for the previous year.

Osteoporosis management and hospital strategy.

As the patient population grows, strategies for preventing osteoporosis and for improving its management are urgently needed. Coordinating the efforts of existing hospital programs may help to meet these goals.

Enhancing independence in the older hip fracture patient.

No doubt all experienced clinicians have observed cases in which a hip fracture dramatically diminished the independence and quality of life of an elderly person. This difficult problem requires a concentrated, multidisciplinary effort. More than 800 patients have now been treated using our interdisciplinary approach. A recent review of the data shows that results in this larger group compare favorably with those in the followup group described in this article. We believe that our approach shows promise as a model for the future. Further, comparisons with current practices may lead in some situations to significant improvements in hip fracture rehabilitation. Primary care physicians play a key role in this process of review and modification and in contributing to the overall restorative effort.

Quantification of trunk muscle performance in standing, semistanding and sitting postures in healthy men.

The purpose of this study was to determine trunk muscle performance in the sitting, semistanding, and standing postures during isometric and dynamic extension and flexion movements. Twenty-five male subject volunteers, with no previous history of back pain participated in the study. A triaxial dynamometer that measures torque, angular position, and velocity was used to measure isometric and dynamic motor output. The dynamometer allows testing in the sitting and standing postures. A custom-designed module also allowed testing in the semistanding posture. Each subject was tested in two sessions. The first session included the physical examination and three trials of isometric maximum voluntary contractions in the three postures. The second session included the dynamic performance against a resistance equal to 50% of the effort, as measured in the first session. Subjects were instructed to perform five repetitive flexion and extension cycles as fast and accurately as possible with maximum effort. An analysis of variance with repeated measures design was used to investigate the effects of the postures (standing, semistanding and sitting), the direction of exertion (flexion and extension), and the interaction effects of the isometric and dynamic parameters (maximum and average torque, velocity, power, and range of motion). The effects of direction (F = 98, P < 0.0001) and the interaction of posture and direction (F = 7.9, P < 0.001) were significant. The maximum isometric flexion strength was significantly higher in the standing posture than in semistanding and sitting. The maximum isometric extension was not affected by the posture (sitting, semistanding and standing).(ABSTRACT TRUNCATED AT 250 WORDS)

Intramedullary nailing of subtrochanteric fractures: a critical review of device failure and case analysis.

Although device failure in intramedullary (IM) nailing of subtrochanteric fractures is uncommon, breakage of the nail can occur. Following a review of the literature on this subject, a case is reported that illustrates the surgical and biomechanical factors that can lead to nail failure.

The logic of imaging in spine surgery.

Spinal imaging has rapidly evolved into a complex diagnostic field requiring specialized expertise. While many imaging modalities reveal portions of a topographic map of the spine necessary for surgery, only magnetic resonance imaging emerges as the imaging modality of widest and most efficacious first choice. With the increasing high-technology sophistication of modern imaging modalities, the spine surgeon must become completely conversant with the radiologic data produced by these imaging techniques. The authors present a logical approach to spinal imaging--an algorithm--based on etiologic classification and aimed at conserving medical resources and developing an optimal diagnostic pathway for spine injury and disease. Spine surgeons are urged to incorporate the interpretative insights of radiologists into the diagnostic process.

New method of limb deformities correction in children.

A new "bloodless" technique (Ilizarov) was used to correct 36 limb deformities in 29 children. There were six leg length discrepancies, five achondroplasias, four deformed feet, five joint contractures, one rotational deformity of tibia, and in three the apparatus was used as an external fixator after corrective osteotomy. Lengthening was accomplished in 15 of the 16 procedures (93%). Average increase in femur length was 10 cm (32%), in tibial length 7.5 cm (30%), in humerus 11 cm (40%). Bony union was achieved in two out of five pseudoarthroses. Four deformed feet were fully corrected. Joint contractures were corrected in four out of five. The complication rate is as high as in other methods but with the Ilizarov apparatus, longer segments of bone were lengthened and more complex deformities were treated. Complications lessened as experience was gained.

Reuse of Ilizarov frame components: a potential cost savings?

Although there is a potential hospital cost savings in reusing Ilizarov frame components, such reuse must be carefully considered in view of the deterioration of the parts during clinical use. A study is presented that addresses this issue through examination of clinically removed frames, laboratory testing, and engineering calculations.

The effect of wire configuration on the stability of the Ilizarov external fixator.

The stability of the basic unit for fixation of the Ilizarov external fixation system was tested in several loading modes. The effects of varying the number of wires and the orientation of wire placement were studied. The fixation units were mounted on a plastic, simulated, long bone and tested by loading in several directions. The Ilizarov fixation ring was found to be relatively stiff in axial compression and torsion. Its stiffness in this mode was directly proportional to the number of wires in the system and independent of the configuration of wire placement. Loading in bending and in shear provided much lower levels of stiffness, and this was dependent on the angles formed between the wires. The addition of a wire at a minimum distance of 4 cm from the primary ring significantly improved bending stiffness. The use of opposed olive wires also improved shear stiffness.

Canine leg lengthening by the Ilizarov technique. A biomechanical, radiologic, and morphologic study.

The mechanical properties of canine tibias lengthened by the Ilizarov method as well as the degree of healing--as determined by the osseous appearance of the limbs using three imaging modalities--were examined as a function of fixator application time. Sixteen mongrel dogs had right tibial lengthening using a two-ring Ilizarov external fixator. The average lengthening was 27 mm. Four groups of four animals were killed at four, six, eight, and ten weeks after the completion of lengthening. The operated and contralateral tibias were examined with biplanar roentgenography, computerized tomography, and technetium scintigraphy. The torsional strengths of the tibias were then determined and histologic analysis was performed. There was considerable variation in the healing rate of the lengthening sites, both within and among groups. Histologic analysis and results of the imaging modalities revealed different degrees of development of the lengthening sites among members of the same group. Two types of mechanical behavior were seen, corresponding to completely and incompletely ossified lengthening zones. The strongest samples were those that had ossified across their lengthening sites by four or six weeks. The degree of recorticalization of the new bone and the extent of formation of a marrow space correlated well with increased torsional strength. The average strength of the fully ossified bones decreased progressively with time, paralleling a decrease in cortical thickness outside the lengthening zone. This seems to be a consequence of stress shielding by the fixator and disuse by the animal.

Humeral lengthening and bone transport using the Ilizarov technique.

The authors present their results of Ilizarov treatment of eight humeral length deficits and bone defects in seven consecutive patients treated at the Hospital for Joint Diseases. The mean humeral lengthening achieved was 9.8 cm. The lengthening goal was completely achieved in six cases, while two cases achieved over 80% of the desired length. No permanent neurovascular or infectious complication occurred. The authors suggest that the Ilizarov technique is a viable method in treating severe humeral length deficits or bone defects.