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Biomedical subjects

C S Ranawat

Publications and source records attributed to C S Ranawat.

At least 19 recordsLinked to original sources
PubMed2001

Posterior cruciate-sacrificing versus posterior cruciate-substituting total knee arthroplasty: a study of clinical and functional outcomes in matched patients.

Since the introduction of the Total Condylar Prosthesis (TCP) in 1974, concomitant improvements in surgical technique and prosthetic design have occurred. The individual effects of each of these variables have not been investigated, however. This study evaluates 2 different knee designs using the same operative technique by a single surgeon. All primary total knee arthroplasties performed between 1986 and 1989 were entered into a database of 2 cohorts, TCP and Press Fit Condylar (PFC) knees, matched for age, gender, body weight, and diagnosis. Follow-up data within 12 months of each other were used, evaluating patients clinically and using a self-administered questionnaire. In each cohort, 74 knees were matched by these criteria. Follow-up time was 4.04 and 4.45 years for the TCP and PFC cohorts. Range of motion averaged 107 degrees and 112 degrees for the TCP and PFC cohorts. This difference was statistically significant. Total knee score and functional score improved significantly. Anterior knee pain was present in 9 TCP and 3 PFC knees. Lateral release was performed in 30 TCP and 18 PFC knees. The PFC showed an advantage in ROM, stair function, anterior knee pain, and use of lateral release. Both designs showed comparable pain relief and walking ability.

Adult↗
PubMed2001

Correction of limb-length inequality during total hip arthroplasty.

Although several methods of intraoperative limb-length measurements have been described, their success in predicting the limb-length correction is not well documented. A new technique of measuring intraoperative limb lengthening using a vertical Steinmann pin at the infracotyloid groove of the acetabulum was studied in 100 consecutive primary total hip arthroplasties. Correlation of the predicted intraoperative correction was done with the postoperative radiographic measurements. Preoperative limb-length inequality ranged from -24 mm (short) to +2 mm (long) (mean, -4.2 mm). Intraoperative measurement of lengthening ranged from 0 to 15 mm (mean, 5.9 mm). Radiographic measurements of postoperative radiographs showed lengthening ranging from 0 to 17 mm (mean, 7.4 mm). There was significant correlation between the 2 values (r =.84). Postoperative limb-length inequality ranged from -7 mm to +8 mm (mean, 1.9 mm). None of the patients had to use shoe lifts for equalization of limb lengths.

Acetabulum↗
PubMed2001

Short-term results of the M2a-taper metal-on-metal articulation.

A polyethylene-free, metal-on-metal acetabular system (M2a-taper [Biomet, Inc., Warsaw, IN]) was designed in an effort to improve total hip arthroplasty (THA) longevity. Minimum 2-year follow-up results involving 72 polyethylene liner THAs and 78 metal liner THAs from a multicenter, randomized, controlled, investigational device exemption study are reported. Mean Harris hip scores of 95.54 (polyethylene liner group) and 95.23 (metal liner group) were reported at mean follow-up intervals of 3.29 and 3.23 years. Radiographic evaluation revealed no evidence of early failure. No acetabular components have been revised or are pending revision. No statistically significant differences in the data were calculated between liner types except for the immediate postoperative (P=.0415) and minimum 2-year follow-up (P=.0341) angles of inclination. The M2a-taper metal-on-metal articulation may represent a viable alternative for THA in younger, higher demand patients.

Adolescent↗
PubMed2001

Metal-backed and all-polyethylene tibial components in total knee replacement.

One hundred seventy-five patients with 243 consecutive primary Press Fit Condylar cruciate-substituting total knee replacements were evaluated at a mean of 5.5 years. One hundred thirteen knees had modular metal-backed tibial components and 130 had all-polyethylene tibial components. The mean knee score and functional score for the patients with unrevised components was not significantly different. The incidence of osteolysis and synovitis was higher in patients in the modular metal-backed tibia group (5%; five patients, six knees). No patients in the all-polyethylene tibia group had osteolysis or synovitis. Five revision operations were necessary: four for osteolytic defects and one for synovitis, all in patients in the modular metal-backed tibia group. All of the retrieved polyethylene inserts had evident backside wear. The best case rate of survival of the all-polyethylene tibial components was 96%+/-0.8% at 7 years and for the modular metal-backed components it was 75%+/-10% at 7 years. Metal backing and modularity were added to the Press Fit Condylar total knee replacement design to improve fixation durability. However, the superiority of the modular metal-backed implants remains in question.

Adolescent↗
PubMed2001

Total condylar knee replacement: a 20-year followup study.

Between 1976 and 1979, 220 total knee replacements were done on 164 patients using the Total Condylar Knee replacement. The diagnosis was rheumatoid arthritis in 111 knees and osteoarthritis in 109 knees. Patients with 157 knees are known to have died as of December 1998, leaving 63 knees in patients who are still alive. Twelve patients with 18 knees were lost to followup. The average 20-year followup data (range, 18-22 years) are presented for 45 knees in 30 patients using Knee Society evaluations. The average Knee Society clinical score for the surviving patients was 88 points, and the average functional score was 58 points. The radiographic followup averaged 19 years. The average overall alignment was 3 degrees valgus. Femoral lucencies were present in 17 of 40 adequate lateral views, most commonly about the anterior and posterior surfaces. Two femoral components were loose. Twenty-two tibial components had radiolucencies; four radiolucencies were circumferential. The remaining 41 knees retained a well-fixed cemented central peg despite proximal interface lucencies. From the group of 220 knees, 14 revisions have been done at an average of 11.4 years postoperative. Two knee replacements were revised for isolated tibial loosening, whereas one knee replacement had isolated femoral loosening. Three knee replacements were revised for loosening of both components, and one was revised for isolated patellar loosening. Four patients had sepsis develop; three of these four patients were treated with two-stage revision, and one underwent fusion. Three patients were treated for supracondylar fractures. The Total Condylar Knee replacement maintains excellent durability at 20-years followup.

Adult↗
PubMed2000

Clinical and radiographic evaluation of the Harris-Galante cup: incidence of wear and osteolysis at 7 to 9 years follow-up.

A retrospective evaluation of the clinical and radiographic results of the Harris-Galante acetabular cups was performed in 112 patients with 127 total hip arthroplasties. Patients with 14 hips had died, and patients with 20 hips were lost to follow-up. A total of 82 patients with 93 hips was available for follow-up. There were 67 men and 45 women. The mean follow-up was 87 months (range, 48-113 months). There were a total of 9 revisions: 2 for recurrent dislocations, 1 for a loose cup, and 6 for wear and osteolysis. Radiographic evaluation demonstrated that 22 (24%) hips had periacetabular osteolysis, and 16 of these 22 (73%) were associated with the screws. Twenty-two hips (23%) demonstrated osteolytic lesions around the femoral stem. Mean femoral head displacement was of 1.00 mm (range, 0.40-4.5 mm) with a rate of 0.16 mm/yr (range, 0.05-0.44 mm/yr). The Harris-Galante socket has maintained a low implant failure rate at intermediate term, even in these young patients. As follow-up increases, wear of the polyethylene and periprosthetic osteolysis may become growing concerns.

Arthroplasty, Replacement, Hip↗
PubMed2000

Anthropometric measurements to design total knee prostheses for the Indian population.

An anthropometric computed tomography scan study was undertaken to design femoral components in 86 knees (47 osteoarthritic Indians-21 men, 26 women) who matched standards suggested by the Indian Council of Medical Research, 1990. Patients were classified into 3 random groups based on anteroposterior diameter (<55 mm, 55-59 mm, >59 mm). Most Indian men (86.8%) could have the femoral component satisfactorily replaced by available designs. A statistically significant number of women (60.4%, P < .001) had femoral anteroposterior diameters smaller than the smallest available (55 mm) femoral component. Splaying in mediolateral dimension (> 10 mm) in a given anteroposterior size was noted in all 3 groups. This pilot study representative of the Indian population can be used to manufacture prosthetic inventories suitable for most of the Asian-Pacific population having smaller anthropometric measurements than Western populations.

Anthropometry↗
PubMed1999

The incidence of venous thromboembolism after total hip arthroplasty: a specific hypotensive epidural anesthesia protocol.

We retrospectively reviewed all consecutive unilateral primary total hip arthroplasty (THA) procedures performed by 3 attending surgeons on the Arthroplasty Service at our institution from January 1, 1990, to December 31, 1993. All surgery was performed under a specific hypotensive epidural anesthesia protocol. Hypotensive epidural anesthesia at our institution provides a lower level of hypotension (mean arterial pressure of 50-60 mmHg) as compared to hypotensive anesthesia used more generally around the world (mean arterial pressure >70 mmHg). For each patient, hospital and postdischarge office records for a minimum of 3 months after surgery were reviewed for the type of postoperative screening test, the incidence of deep venous thrombosis (DVT), and the incidence of symptomatic pulmonary embolism (PE). Overall, 2,592 primary unilateral THAs were performed with 78.6% (2,037 of 2,592) of patients receiving a venogram. Our protocol for thromboembolic disease prophylaxis in these patients included aspirin postoperatively as well as antithromboembolic disease stockings and early ambulation (24-48 hours postoperatively). The 555 patients who did not receive venography were managed with a different protocol that included warfarin postoperatively as well as antithromboembolic disease stockings and early ambulation. This high-risk group consisted of patients who received warfarin preoperatively (ie, cardiac valve) or patients with a history of DVT who were to receive warfarin postoperatively, regardless of venography result. Overall, DVT was diagnosed in 10.3% (210 of 2,037) of patients who had a venogram. Of these patients who had venography, 2.3% (46 of 2,037) had an isolated proximal DVT; 6.0% (123 of 2,037), a distal DVT; and 2.0% (41 of 2,037), both a proximal and a distal DVT. Of the 87 cases of proximal DVT identified, 60.9% (53 of 87) were femoral DVT; 18.4% (16 of 87), popliteal DVT; and 20.7% (18 of 87), both femoral and popliteal DVT. Of the 164 distal DVT, 68.3% (112 of 164) were major calf DVT and 31.7% (52 of 164) were minor calf DVT. The overall incidence of major venous thrombosis (sum of proximal and major calf thrombi) was 9.8% (199 of 2,037) in patients who had venography. Ventilation-perfusion scanning was used selectively in patients symptomatic for PE. Overall, symptomatic PE was diagnosed by ventilation-perfusion scan in 1.0% (26 of 2,592) of patients, with 0.58% (15 of 2,592) of patients having an in-hospital PE. Of the 15 patients who had an in-hospital PE, 11 patients had a venogram, and only 3 of 11 were positive. Late symptomatic PE was defined from discharge (mean, 7 +/- 2 days) to 3 months after discharge from the hospital and occurred in 0.42% (11 of 2,592) of patients. One of the 11 late symptomatic PEs was fatal. In the overall study, this represents 0.04% (1 of 2,592) fatal PE. Of the 11 patients with a late symptomatic PE, 10 had venograms in the hospital, and all 10 were negative for DVT. Overall, in the patients with a positive venogram, the incidence of symptomatic PE was 1.4% (3 of 210), whereas in the patients with a negative venogram, the incidence of symptomatic PE was 0.44% (8 of 1,827). At our institution, patients who undergo primary THA performed with hypotensive epidural anesthesia, postoperative aspirin, antithromboembolic disease stockings, and early ambulation have a low risk for thromboembolic disease.

Anesthesia, Epidural↗
PubMed1999

Assessment of postoperative vigor in patients undergoing elective total joint arthroplasty: a concise patient- and caregiver-based instrument.

Assessment of early postoperative recuperative power (i.e., vigor and functional ability) in surgery patients is considered to be important for optimizing patient rehabilitation, discharge planning, and health system resource utilization. However, no broadly accepted method of patient assessment has been available to measure these parameters. Therefore, a panel of experts was assembled to design an instrument to assess recuperative power in the total joint arthroplasty setting. The instrument consists of both subjective, patient-based, preoperative and postoperative, fixed-ended questions and objective, caregiver-based measures of patient function (i.e., muscle strength and hematocrit [HCT]). The prototype instrument employed the vitality subscale of the Short Form-36 (SF-36), the activities of daily living items from the Western Ontario and McMaster University Osteoarthritis Index (WOMAC-ADL), as well as three novel scales: Well-being, Ready to resume activities, and Ready to leave the hospital. The instrument was tested in 65 patients at two medical centers. The reliability and validity of the three novel psychometric scales were tested by measuring internal consistency and validity by comparison with the standard scales. Postoperative patient Well-being and Ready scales correlated strongly with muscle strength (P < .01), while postoperative HCT correlated with muscle strength (r = 0.4) and Ready scale (P < .01). This analysis suggested that patient well-being and readiness to resume normal activities may be the best surrogates of patient vigor and that these parametric assessments correlate well with functional and laboratory measures of vigor (i.e., muscle strength and HCT). Based on these findings, the final instrument (Version 4.2) consists of a patient questionnaire that can be completed within approximately 5 minutes (12 preoperative and 14 postoperative questions), and a caregiver questionnaire that includes two objective functional tests: muscle strength and HCT. In conclusion, postoperative vigor may be able to be assessed with a concise, patient-based instrument and may provide valuable information for rehabilitation and discharge planning. The utility of this instrument is currently being assessed in a prospective clinical study.

Activities of Daily Living↗
PubMed1999

In pursuit of excellence: personal reflections.

I have put together some of the elements that will allow a person to advance and succeed in life. On a personal note, I would not be where I am without the support of my parents, teachers, colleagues, residents, and fellows. Special appreciation goes to my wife, my children, and my office staff. Without their support, this story would be incomplete. Thank all of you for putting your trust in me.

Education↗
PubMed1998

Polyethylene wear and periprosthetic osteolysis in metal-backed acetabular components with cylindrical liners.

A retrospective clinical and radiographic analysis was performed in 27 hips (23 patients), in which a threaded, porous-coated acetabular component with cylindrical liner was implanted (Sintered T-Tab-ST cup, Biomet, Warsaw, IN). Sixteen hips had cemented stems; 11 had cementless, circumferentially porous-coated stems. The mean clinical and radiographic follow-up period was 68 months. The mean patient age was 49 years; the mean patient weight was 68 kg. The mean rates of linear and volumetric wear were 0.25 mm/y and 149 mm3/y, respectively. Osteolysis occurred in 51.8% (14 hips). Wear rate and young age correlated with osteolysis (P = .0002 and P = .01, respectively). There were no cases of distal femoral osteolysis.

Acetabulum↗