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Biomedical subjects

R E Windsor

Publications and source records attributed to R E Windsor.

At least 19 recordsLinked to original sources
PubMed2001

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.

Biomechanical Phenomena↗
PubMed2000

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.

Analgesics↗
PubMed1999

Infected total knee arthroplasty treated with arthrodesis using a modular nail.

Failed treatment of infected total knee replacement presents few attractive surgical options. Knee arthrodesis is challenging surgically and can be complicated by nonunion, malunion, or recurrent infection. Recently, a modular titanium intramedullary nail has been used in an attempt to reduce the incidence of nonunion and the rate of complications. In the present study, a review of the results of knee arthrodesis after infected total knee arthroplasty in 21 patients at three large academic institutions was performed. All patients were followed up for a mean of 2.4 years (range, 2-7.5 years). The mean age of the patients was 64 years. The mean number of previous operations was four (range, 2-9 operations). A solid arthrodesis was achieved without additional surgical treatment in 20 of 21 patients (95%). The mean time to fusion was 6.3 months. The one patient who suffered a nonunion achieved fusion after a subsequent bone grafting procedure. Based on the present study, intramedullary arthrodesis with a coupled titanium nail, is a reliable, effective method of achieving fusion after infection of a total knee arthroplasty. This procedure resulted in a high rate of fusion and a lower rate of complications when compared with traditional methods of arthrodesis.

Aged↗
PubMed1998

Patella height after high tibial osteotomy with internal fixation and early motion.

The purpose of this study was to compare the incidence of patella infera in patients after high tibial osteotomy treated with either postoperative immobilization or internal fixation and early range of motion. A retrospective review of 98 patients with high tibial osteotomy was done at the authors' institution. Thirty-three patients who had secondary procedures such as concomitant ligamentous reconstruction with early motion were excluded. Therefore, 69 knees in 65 patients remained in the study cohort. Group A consisted of 32 patients (34 knees) treated with postoperative immobilization, whereas Group B included 33 patients (35 knees) treated with internal fixation and early motion. The preoperative and postoperative Insall-Salvati index, Blackburne-Peel index, and angular alignment were determined for each group. Between Groups A and B, the differences in the Insall-Salvati index and the Blackburne-Peel index were statistically significant, although the difference in angular correction was not significant. With rigid fixation and early motion the Insall-Salvati index showed that there was less postoperative shortening of the patellar tendon. The relationship of the patella to the remainder of the knee was affected less adversely as evidenced by the Blackburne-Peel index. High tibial osteotomy with internal fixation and early range of motion should result in a better knee and ease the subsequent performance of a total knee arthroplasty.

Arthroplasty, Replacement, Knee↗
PubMed1998

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.

Aged↗
PubMed1998

Primary total knee arthroplasty in stiff and ankylosed knees.

This study reviewed 71 patients who underwent 82 total knee arthroplasties between 1974 and 1987. All patients had severe limitations of motion preoperatively with a total preoperative arc of motion of < or = 50 degrees. Follow-up ranged from 2 to 12 years (average: 5.3 years). The average preoperative knee score was 38 (range: 14 to 54). The average preoperative arc of motion was 36 degrees (range: 0 degree to 50 degrees), with an average flexion contracture of 22 degrees average maximum flexion of 58 degrees. Postoperatively, the average knee score was 80 (range: 0 to 98). The average postoperative arc of motion was 93 degrees (range: 35 degrees to 130 degrees), with an average maximum flexion of 94 degrees. Nine knees had 5 degrees flexion contractures, while 5 knees had 10 degrees flexion contractures. Postoperatively, no knee had a flexion contracture > 10 degrees. Two knees had a decreased range of motion postoperatively. Two knees with severe flexion-valgus deformities developed peroneal nerve palsies that both resolved. Total knee arthroplasty in stiff or ankylosed knees can produce good or excellent results and can lead to significant improvement in range of motion and pain.

Arthritis, Rheumatoid↗
PubMed1996

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.

Adult↗
PubMed1996

Knee closure in total knee replacement: a randomized prospective trial.

A randomized prospective study of 75 total knee replacements in 64 patients who were randomized to capsular closure with the knee in full extension or in flexion was done. Thirty-one knees received a posterior cruciate ligament retaining prosthesis and 44 knees received a posterior stabilized prosthesis. Preoperatively, there was no significant difference between the groups, and patients were stratified by surgeon and type of prosthesis. Postoperatively, all patients were evaluated by a physical therapist who did not know the type of prosthesis the patient received. In addition to the range of motion obtained at discharge; the number of days required to achieve unassisted transfer; the number of days required to achieve assisted and unassisted use of a walker, cane, and stairs; and the number of days to discharge from the hospital were recorded. All patients were also evaluated at 2 to 3 months postoperatively, and the Knee Society clinical rating system scores were compared. There was no statistically significant difference in any of the early rehabilitation parameters or in the 2- to 3-month followup data. Moreover, there was no statistically significant difference in the rate of complications. With stratification according to the type of prosthesis used or the surgeon performing the operation, there was still no statistically significant difference in any of the studied parameters. It was therefore concluded that the degree of knee flexion at the time of capsular closure in total knee replacement has no effect on early rehabilitation after total knee replacement.

Activities of Daily Living↗
PubMed1996

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.

Aged↗
PubMed1996

Arthroscopic release of the posterior cruciate ligament for stiff total knee arthroplasty.

Ten posterior cruciate ligament sparing total knee arthroplasties were studied in 9 patients who underwent arthroscopic posterior cruciate ligament release to improve intractable postoperative knee stiffness and pain. Mean patient age was 64 years. Before posterior cruciate ligament release, the mean knee extension was 4 degrees (0 degrees - 10 degrees); mean knee flexion was 73.9 degrees (40 degrees - 110 degrees). The mean interval to posterior cruciate ligament release after primary total knee arthroplasty was 29 months. After release, mean extension was 1.3 degrees (0 degrees - 10 degrees) and mean flexion was 112 degrees (range, 85 degrees - 135 degrees). The average increase in flexion observed in the immediate postoperative period was 40.1 degrees (25 degrees - 60 degrees). At a mean followup of 20 months, mean extension was 1.5 degrees (0 degrees - 10 degrees), and mean flexion was 104.5 degrees (70 degrees - 125 degrees). At followup, the average increase in knee flexion was 30.5 degrees (10 degrees - 50 degrees). Before arthroscopic posterior cruciate ligament release, the average Knee Society knee and function scores were 70.9 and 71, respectively. At followup, the average Knee Society knee and function scores were 86.4 and 88, respectively. The Knee Society pain score improved from 33.5 preoperatively to 42 postoperatively. All patients reported subjective improvements in pain and stiffness. Eight patients (88%) reported satisfaction with the procedure. Two patients (22%) eventually required revision total knee arthroplasty.

Adult↗
PubMed1996

Randomized trial of epidural versus general anesthesia: outcomes after primary total knee replacement.

To compare the effects of epidural anesthesia and general anesthesia on early postoperative outcomes after unilateral primary total knee replacement, 262 patients were randomly assigned to receive either epidural or general anesthesia. All patients received a common rehabilitation protocol including a standardized assessment of progress. One hundred eighty-eight patients received a common thromboembolic prophylaxis protocol with postoperative aspirin, and had a standardized surveillance protocol to detect thromboembolic complications. Deep vein thrombosis was determined by venography on the operative limb, and pulmonary embolism was determined by comparison of preoperative and postoperative lung perfusion scans. The epidural anesthesia group reached all rehabilitative milestones earlier postoperatively than did the general anesthesia group, with a statistically significant earlier attainment of stair climbing. The incidence of deep vein thrombosis was 40% with epidural anesthesia, and 48% with general anesthesia. There were no clots proximal to the popliteal veins. The incidence of pulmonary embolism on lung scan was 12% with epidural anesthesia and 9% with general anesthesia. Epidural anesthesia is associated with more rapid achievement of postoperative in hospital rehabilitation goals after total knee replacement. A minor reduction in postoperative deep vein thrombosis rate was observed with epidural anesthesia, but this did not reach statistical significance. No difference in early postoperative pulmonary embolism was observed between the 2 types of anesthesia.

Aged↗
PubMed1995

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)

Aged↗
PubMed1993

Treatment of nonunions about the knee utilizing custom total knee arthroplasty with press-fit intramedullary stems.

Juxta-articular nonunion about the knee is infrequent but may be a troublesome problem, especially if it is about a total knee arthroplasty or associated with an arthritic joint. This technique of total knee arthroplasty with an uncemented press-fit intramedullary rod and bone grafting achieved union in all nine nonunions about the knee. Radiographic review indicated all nonunions to be healed by an average of 2 months, with none taking longer than 6 months to heal. The average postoperative Hospital for Special Surgery knee score was 78 (range, 50-91), with 4 excellent, 4 good, and 1 poor result. This study demonstrated that this is a successful salvage procedure for juxta-articular nonunions in the face of either arthritis in the adjacent joint, severe articular incongruency, or an ipsilateral total knee arthroplasty.

Bone Transplantation↗
PubMed1993

Gastrocnemius muscle flap coverage of exposed or infected knee prostheses.

A retrospective analysis was performed of 12 patients who required soft-tissue coverage of an exposed or infected total knee prosthesis between 1982 and 1989. All knees had skin closure with medial gastrocnemius muscle flaps. At a mean follow-up period of 41 months, all patients who were treated for infected prostheses with removal of the implant, intravenous antibiotics, and muscle flap closure had an excellent clinical result with complete skin coverage and no infection. Five of the six patients went on to successful reimplantation. Of the patients with an exposed prosthesis, five of six had an excellent outcome with retention of the prosthesis. Thus, 11 of 12 patients (92%) who had medial gastrocnemius flap coverage of an exposed or infected knee prosthesis had an excellent outcome, with ten of 12 patients (82%) retaining their prostheses or having a successful reimplantation. No medial gastrocnemius flap failed after standard primary or revision total knee arthroplasty. Gastrocnemius muscle flaps provide excellent soft-tissue coverage of exposed or infected knee prostheses and facilitate surgical care of this difficult problem.

Adolescent↗
PubMed1992

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.

Aspirin↗
PubMed1991

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.

Amputation, Surgical↗
PubMed1990

Total knee arthroplasty in diabetes mellitus.

A retrospective study was done of 59 total knee arthroplasties (TKAs) in 40 patients diagnosed with diabetes mellitus. The overall infection rate was 7%, with an overall revision rate of 10% and an average follow-up period of 4.3 years. Wound complications were present in 12% of the TKAs. The rate of deep joint infections in diabetic patients was statistically higher than the reported incidence of sepsis in nondiabetic patients. Therefore, maximum precautions should be taken for diabetic patients having TKA to minimize both wound complications and joint sepsis.

Aged↗