Fracture healing in the rabbit fibula when subjected to various capacitively coupled electrical fields.

The effect of capacitively coupled electrical stimulation on the healing of midshaft transverse osteotomies of the rabbit fibula is assessed roentgenographically, mechanically, and histologically. The results show that a dose-response curve for capacitive coupling and fracture healing exists and that a 220 mV, 250 microA, 60 kHz applied electrical signal (0.33 V/cm internal electric field) is the most effective signal for fracture stimulation in this model.

Technical considerations of total knee arthroplasty after proximal tibial osteotomy.

Forty-five total knee replacements in forty-one patients who had continued to have progressive osteoarthritis after a proximal tibial osteotomy were evaluated prospectively. There were 51 per cent excellent, 29 per cent good, 4 per cent fair, and 16 per cent poor results after a minimum follow-up of two years. The resection of tibial bone that was produced by the osteotomy could not be related causally to the fair or poor clinical results that were found after arthroplasty. Radiographic study, however, showed that 80 per cent of the knees had patella infera before the arthroplasty, which may contribute to altered biomechanics of the patellofemoral joint of the arthroplasty. The procedure for total knee replacement is made more difficult by the previous osteotomy, and a custom-made prosthesis may be required. The clinical results that were obtained in this series are similar to those for the revision total knee arthroplasties that have been done at this institution, but they were not as satisfactory as those that were obtained after primary total knee replacement. Our results should be considered when a surgeon compares the advantages and disadvantages of proximal tibial osteotomy with those of total knee arthroplasty for an older patient who has unicompartmental osteoarthritis of the knee.

Revision total knee arthroplasty with use of modular components with stems inserted without cement.

We reviewed the results of seventy-six revision total knee replacements, performed between 1980 and 1988 on the Knee Service at The Hospital for Special Surgery, in seventy-four patients. Sixty-five patients (sixty-seven knees; 88 percent) had a complete clinical examination and radiographic evaluation, and nine patients (nine knees; 12 percent) were only interviewed by telephone. Survivorship analysis was performed for all patients. The average duration of follow-up was three years and six months (range, two to nine years). Only patients who had had revision of the femoral component or the tibial component, or both, because of aseptic failure were included. The tibial component of all prostheses that were used for revision had a metal backing. Cement was placed on the cut surfaces in the metaphyseal region of the femur and tibia. Fluted diaphyseal intramedullary rods were used in all patients and were not cemented. Metal wedges and augments were used to fill osseous defects when necessary. The average preoperative knee score, according to the rating scale of The Hospital for Special Surgery, was 49 points (range, 0 to 62 points). Postoperatively, the knee score improved to an average of 76 points (range, 0 to 97 points). Of the sixty-seven knees that had complete follow-up, fifty-six (84 percent) had an excellent or good result and five (7 percent) had a fair or poor result. In six (8 percent) of the seventy-six knees, the prosthesis failed, necessitating another revision. Failure was defined as removal or a recommendation for removal of the implant.(ABSTRACT TRUNCATED AT 250 WORDS)

Observations on patellar height after proximal tibial osteotomy.

Sixty-six knees (sixty patients) that had had a proximal tibial osteotomy were evaluated to determine if any alteration of the patellar height had occurred as a result of the operation. Eighty-nine per cent of the patellae, as measured by the Insall-Salvati index, and 76.3 per cent, as measured by the Blackburne-Peel index, were observed to be lowered as they appeared on the postoperative lateral radiograph. This was probably due to shortening of the patellar ligament after prolonged immobilization in a cast, interstitial scarring of the patellar ligament, and new-bone formation in the area of insertion of the patellar ligament. There was no correlation between the postoperative height of the patella and the need for subsequent revision to a total knee replacement.

Two-stage reimplantation for the salvage of total knee arthroplasty complicated by infection. Further follow-up and refinement of indications.

Thirty-eight total knee replacements (in thirty-five patients) that were complicated by infection were treated with a two-stage protocol for reimplantation. The clinical results in these knees (nine of which have been previously reported on) were evaluated at an average follow-up of four years (range, 2.5 to ten years). There was only one documented recurrence of infection with the original organism. Three patients in whom the immunological system was suppressed had a subsequent hematogenous infection with a different organism. According to the knee-rating system of The Hospital for Special Surgery, there were eleven excellent, thirteen good, six fair, and seven poor results. For one patient who had severe polyarticular rheumatoid arthritis, the result could not be rated. The results of this study suggested that the two-stage protocol for reimplantation, with a six-week interval of intravenous antibiotic therapy, is the procedure of choice for the treatment of an infection around a total knee arthroplasty. A patient who has polyarticular rheumatoid arthritis and in whom the immunological system is suppressed may not be an ideal candidate for the protocol. Gram-negative bacterial infection may be treated with this protocol, provided the organism is sensitive to relatively non-toxic antibiotic medication.

Pneumatic sequential-compression boots compared with aspirin prophylaxis of deep-vein thrombosis after total knee arthroplasty.

This prospective, randomized study was undertaken to compare the effectiveness of pneumatic sequential-compression boots with that of aspirin in preventing deep-vein thrombosis after total knee arthroplasty. Patients were randomly assigned to one of two prophylactic regimens: compression boots or aspirin. One hundred and nineteen patients completed the study. Seventy-two patients had unilateral arthroplasty and forty-seven, one-stage bilateral arthroplasty. In the unilateral group, the incidence of deep-vein thrombosis was 22 per cent for the patients who used compression boots compared with 47 per cent for those who received aspirin (p less than 0.03). In the bilateral group, the incidence of deep-vein thrombosis was 48 per cent for the patients who used compression boots compared with 68 per cent for those who received aspirin (p less than 0.20). The results confirm the effectiveness of compression boots in the treatment of patients who have had unilateral total knee arthroplasty. Despite the use of compression boots, however, patients who had bilateral arthroplasty were at greater risk for the development of deep-vein thrombosis.

Contralateral total hip arthroplasty or ipsilateral total knee arthroplasty in patients who have a long-standing fusion of the hip.

We studied the cases of twenty patients who had had an ipsilateral total knee arthroplasty or a contralateral total hip arthroplasty, or both, long after one hip had been fused in an acceptable position. Between 1972 and 1986, we performed twenty-one total joint arthroplasties (on thirteen hips and eight knees) and followed two additional patients (one hip and one knee) in whom the operation had been performed elsewhere. The average age of the patients at the time of arthroplasty was fifty-seven years (range, thirty-one to eighty-one years), and the average time from arthrodesis to arthroplasty was thirty-two years (range, eleven to fifty-four years). The results of eighteen of the twenty-three arthroplasties were evaluated at an average of seven years and nine months postoperatively. Four of the remaining five patients, who were followed for an average of eight years, died of a cause that was unrelated to the arthroplasty. After the hip arthroplasty, five hips were rated excellent; five, good; one, fair; and three, poor. Each hip that had a poor result was revised twice for mechanical loosening. Three hips for which the result was not considered poor had progressive radiolucency. After the knee arthroplasty, three knees were rated excellent; four, good; one, fair; and one, poor (because of infection). Seven knees were manipulated a total of fifteen times. Only one patient had progressive symptomatic radiolucency, nine years after the insertion of a posterior stabilized prosthesis. Clinically important ligamentous instability was not encountered.(ABSTRACT TRUNCATED AT 250 WORDS)

Survivorship of cemented knee replacements.

The survivorship method of analysis has been used to compare the failure rate and overall success of 1,430 cemented primary total knee arthroplasties performed at The Hospital for Special Surgery over a 15-year period. There were 224 total condylar prostheses with a polyethylene tibia, 289 of the posterior stabilised type with an all polyethylene tibia, and 917 posterior stabilised with a metal-backed tibial component. There were 12 failures in the total condylar series, giving an average annual failure rate of 0.65% and a 15-year success rate of 90.56%. The posterior stabilised prosthesis with a polyethylene tibia showed an average annual failure rate of 0.27% and a 10-year success rate of 97.34%, and this prosthesis with a metal-backed tibial component gave an annual failure rate of 0.19% and a seven-year success rate of 98.75%. The overall survival rate was not influenced by sex or age, diagnosis or the percentage of ideal body weight. No metal-backed tibial components have yet needed revision for loosening. It seems that infection will be the major cause of failure.

The significance of calf thrombi after total knee arthroplasty.

We reviewed the records of 1257 patients having 1625 total knee arthroplasties; all had pre-operative and postoperative perfusion lung scans and postoperative venograms which were classified as showing no thrombi, calf thrombi or proximal thrombi. Patients with calf thrombi were found to have a significantly greater risk for both symptomatic and asymptomatic pulmonary embolism compared with patients with no venographic thrombi. There were positive lung scans in 6.9% of patients with calf thrombi compared with 2.0% of patients with negative venograms (p < 0.001). Symptomatic pulmonary embolism occurred in 1.6% of patients with calf thrombi compared with 0.2% of patients with negative venograms (p = 0.034). The risk of pulmonary embolism was not significantly different between patients with treated proximal thrombi, and those with calf thrombi. Patients who develop deep-vein thrombosis despite prophylaxis are at increased risk for pulmonary embolism; these patients should receive treatment, or undergo follow-up studies to detect proximal propagation.

Venous haemodynamics after total knee arthroplasty: evaluation of active dorsal to plantar flexion and several mechanical compression devices.

We performed a crossover study to evaluate the haemodynamic effect of active dorsal to plantar flexion and seven pneumatic compression devices in ten patients who had a total knee arthroplasty. Using the Acuson 128XP/10 duplex ultrasound unit with a 5MHz linear array probe, we assessed the augmentation of peak venous velocity and venous volume above and below the junction of the greater saphenous and common femoral veins in order to study both the deep and superficial venous systems. The pneumatic compression devices evaluated included two foot pumps (A-V Impulse System and PlexiPulse Foot), a foot-calf pump (PlexiPulse Foot-Calf), a calf pump (VenaFlow System) and three calf-thigh pumps (SCD System, Flowtron DVT and Jobst Athrombic Pump). The devices differed in a number of ways, including the length and location of the sleeve and bladder, the frequency and duration of activation, the rate of pressure rise, and the maximum pressure achieved. A randomisation table was used to determine the order of the test conditions for each patient. The enhancement of peak venous velocity occurred primarily in the deep venous system below the level of the saphenofemoral junction. The increases in peak venous velocity were as follows: active dorsal to plantar flexion 175%; foot pumps, A-V Impulse System 29% and PlexiPulse 65%; foot-calf pump, PlexiPulse, 221%; calf pump, VenaFlow, 302% and calf-thigh pumps, Flowtron DVT 87%, SCD System 116% and Jobst Athrombic Pump 263%. All the devices augmented venous volume, the greatest effect being seen with those incorporating calf compression. The increases in ml/min were found in the deep venous system as follows: foot pumps, A-V Impulse System 9.6 and PlexiPulse Foot 16.7; foot-calf pump, PlexiPulse, 38.1; calf pump, VenaFlow, 26.2; calf-thigh pumps, Flowtron DVT 61.5, SCD System 34.7 and Jobst Athrombic Pump 82.3. Active dorsal to plantar flexion generated 8.5 ml for a single calf contraction.

Management of total knee arthroplasty infection.

The treatment of infected total knee arthroplasty represents the most difficult form of revision surgery. Successful salvage of this complication can be accomplished only by extensive investment of surgical and infectious disease efforts in eradicating the infection. A two-stage reimplantation procedure for treating this condition has been the most successful functional option and should be utilized whenever possible to definitively eradicate the infection and ensure good function of the knee joint. It is the procedure of choice for younger healthy patients who can medically tolerate the protocol. Other options may be necessary as the medical condition of the patient dictates. Initial debridement with antibiotic suppression and antibiotic suppression alone have yielded limited successful results but can be accomplished only in a small number (23%) of patients.

Anabolic steroid use by athletes. How serious are the health hazards?

Use of anabolic steroids is widespread in the athletic community, especially among power athletes, who have used them for about 30 years. Despite educational and preventive measures, steroid use has increased. Controversy continues regarding the enhancement of athletic performance and the incidence of major side effects. Some investigators have suggested that the hazards of anabolic steroids may be overstated in the diseased population and are minimal or absent in healthy subjects. Yet, many questions are unanswered. Current data do not link life-threatening side effects with intermittent use of anabolic steroids. However, many concerns remain. Dangerous situations include use of anabolic steroids by adolescents, preadolescents, and persons with liver or heart disease and use of oral compounds in high doses for long periods. A coordinated team approach (with representatives from sports, medicine, advertising, and the pharmaceutical industry) is needed to determine the real risks of anabolic steroids to athletes who are considering their use.

Complications of common selective spinal injections: prevention and management.

Selective spinal injections are being performed with increasing frequency in the management of acute and chronic pain syndromes. Because these procedures require a needle to be placed in or around the spine, there is always a risk of complications. For this reason, prevention, early recognition, and management of complications are paramount to patient care. Physician training and patient preparation and monitoring are required to maximize the safety and efficacy of the specific spinal procedures. This focused review article discusses the primary general and specific complications of spinal injection procedures as well as treatments.

Subsartorial Entrapment of the Saphenous Nerve of a Competitive.

In brief: A 40-year-old bodybuilder had a six- week history of progressively worsening pain of the medial part of her right knee that did not respond to rest and a nonsteroidal anti-inflammatory drug (NSAID). Somatosensory evoked potential readings suggested that both branches of the right saphenous nerve were entrapped. Management consisting of two intramuscular injections of bupivacaine, administrations of two different NSAIDs, and application of knee wraps around the subsartorial region resolved the patient's symptoms within five weeks. She then resumed an intensive lower-extremity exercise regimen without discomfort, in preparation for a bodybuilding competition.

Bone-block iliotibial band reconstruction for anterior cruciate insufficiency. Follow-up note and minimum five-year follow-up period.

Sixty-two of 71 patients (87%) who received a bone-block iliotibial band transfer were followed with a minimum follow-up period of five years (range, 5-10 years). Sixteen of the originally studied knees were examined with an average follow-up period of 104 months (range, 90-120 months). A second group of 46 knees was studied at an average follow-up period of 75 months (range, 60-92 months). Preoperatively, all patients had giving way (buckling). The average postoperative score of the original group was 83 (range, 52-99 points). There were nine excellent, three good, and four poor results. The average postoperative score of the second group was 89 (range, 73-99 points). There were 24 excellent, 18 good, and four fair results. Giving way was absent in 93% of the patients postoperatively; 88% had a negative pivot-shift test. Sixty-eight percent of the patients no longer used a brace for sports, 24% wore a brace for protection only, and 8% used it for instability. Improvement of at least one grade in the Lachman and anterior drawer tests was found in 61% and 85% of the patients, respectively. Pain was the major reason for fair and poor results. All but one had previous meniscectomy. There were no fair or poor results with menisci intact. So far, there has been no deterioration with time. The procedure remains ideal for recreational athletes who cannot afford a long absence from work and for those patients whose daily activities are compromised by recurrent knee instability.

Alterations in the patella after a high tibial or distal femoral osteotomy.

Knee osteotomies realign the knee in an attempt to better distribute forces across the knee. The anatomic and physiologic function of the extensor mechanism, which includes the quadriceps tendon, patella, and patella ligament, may be altered during this procedure. An understanding of these changes is important especially when additional surgery becomes necessary, such as a conversion to a total knee arthroplasty. The current authors discuss patella mechanics and changes in the patella associated with osteotomies about the knee and the influence on normal patella biomechanics. Although patella changes are uncommon after a distal femoral osteotomy, poor total knee arthroplasty outcomes after a high tibial osteotomy attributable to patella alterations exist. Surgical technique during the primary high tibial osteotomy and the conversion to the total knee arthroplasty can reliably improve the final outcome. Rigid internal fixation with early knee mobilization after high tibial osteotomy reduces the incidence of patella baja and improves total knee arthroplasty outcome after a high tibial osteotomy, whereas while patella changes after a distal femoral osteotomy are minimal and largely ignored.

Revision of well-fixed cemented, porous total knee arthroplasty. Report of six cases.

Revision of cemented, porous ingrowth total knee arthroplasties poses several technical problems that are unique to these implants, especially component extraction. Six cases are presented to illustrate these difficulties, with particular attention given to revision techniques. The revisions were performed not for aseptic loosening but for causes in which all the implants were securely affixed to bone. To avoid large amounts of bone loss during extraction, the cement-prosthesis interface should be disrupted with high-speed instruments, such as a high-speed burr or oscillating saw. The tibial component may need to be disassembled to gain access to the tibial fixation peg. The potential problems of revision of cemented, porous total knee implants may necessitate bone grafting or custom-designed prostheses.

Patellar fractures in total knee arthroplasty.

The incidence of patellar fractures following total knee arthroplasty varies from 3% to 21%. This problem has been attributed to avascular necrosis of the patella secondary to the surgical approach, including medial arthrotomy and lateral release, patellar bone resection, thermal necrosis, and anatomic variation. Management of these patellar fractures may be conservative or surgical.

Total knee replacement infection after 2-stage reimplantation: results of subsequent 2-stage reimplantation.

Twelve patients who underwent salvage of an infected total knee replacement with removal, debridement, 6 weeks of parenteral antibiotics, and reimplantation subsequently acquired another infection in the same knee. These patients were again treated with the same protocol followed by reimplantation or arthrodesis and were observed for an average of 31 months. Nine of the patients underwent reimplantation surgery and 3 of the patients underwent arthrodesis. At followup the average Hospital for Special Surgery knee score for the reimplantation group was 84, the average Knee Society knee score was 79, and the average functional score was 73. The 3 patients who did not undergo reimplantation surgery had solid fusions in good position but were dissatisfied with their stiff limb. No knee to date has shown signs of recurrent infection.