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Chitranjan S Ranawat

Publications and source records attributed to Chitranjan S Ranawat.

At least 19 recordsLinked to original sources
PubMed2006

Sciatic nerve palsy after primary total hip arthroplasty: a new perspective.

More than half of sciatic nerve palsies after primary total hip arthroplasties are unexplained. In 2 such cases, magnetic resonance imaging localized compressive injury between the ischial tuberosity and femoral insertion of the gluteus maximus. After these cases, we hypothesized that during limb positioning, the sciatic nerve is compressed by the gluteus maximus tendon. We present the magnetic resonance imaging findings from these 2 cases and compare the number of sciatic nerve palsies in patients with release of the gluteus maximus tendon to patients without release during primary total hip arthroplasty. There were no cases of sciatic nerve palsy when the gluteus maximus was released, compared with 3 cases in the control group.

Arthroplasty, Replacement, Hip↗
PubMed2006

Serum metal levels and bearing surfaces in total hip arthroplasty.

This study evaluates steady-state serum metal levels in patients with 4 different combinations of fixation modalities, materials, and bearing couples. Forty patients with a minimum of 5 years of follow-up and with well-functioning primary total hip arthroplasty were recruited to have serum metal levels measured. Serum chromium and cobalt levels in the metal-on-metal cohort were significantly higher (P < .05) than the other 3 cohorts. The noncemented ceramic-polyethylene cohort had significantly lower (P < .05) serum chromium levels compared to cemented and noncemented metal-polyethylene cohorts and significantly higher serum titanium levels compared to the cemented metal-polyethylene cohort which had no titanium-containing implants. Debris generated at the metal head/neck modular junction likely accounts for the significantly lower serum chromium concentration in ceramic-polyethylene bearing couples.

Aged↗
PubMed2006

Bone graft for tibial defects in total knee arthroplasty. 1986.

Twenty-four knees with bone grafts for tibial defects at the time of either primary or revision total knee arthroplasty were followed for three to six years. With 22 of 24 bone grafts, union and revascularization were seen and no clinical collapse was present. In two, nonunion occurred, accompanied by collapse in one. Failure was attributed to varus alignment of the leg in one (a medial condylar graft) and to insufficient preparation of the bony bed in the second (bleeding bone was not exposed). Evidence for incorporation of the grafts was obtained by tomogram, bone scan, and bone biopsy. Incorporation was present by six months, but the time to complete remodeling was not determined. A bone graft is recommended for tibial defect involving 50% or more of the bony support of either tibial plateau. A bone graft is indicated whenever a cement column under the prosthesis would measure more than 5 mm in height.

Arthritis, Rheumatoid↗
PubMed2006

The P.F.C. sigma RP-F total knee arthroplasty: designed for improved performance.

The new P.F.C. Sigma RP-F (rotating-platform high-flexion) knee has been designed to permit 155 degrees of flexion after total knee arthroplasty (TKA) without compromising wear, polyethylene contact stresses, patellofemoral tracking, or stability. The purpose of this article is to describe the design features of the P.F.C. Sigma RP-F TKA. It is our belief that future primary posterior-stabilized TKA will incorporate many of the design features of the RP-F knee for improved performance.

Arthroplasty, Replacement, Knee↗
PubMed2006

The P.F.C. sigma RP-F TKA designed for improved performance: a matched-pair study.

The press fit condylar P.F.C. Sigma RP-F (rotating-platform, high flexion) knee is designed to provide a range of motion (ROM) of 155 degrees without compromising wear, polyethylene contact stresses, patellofemoral tracking, or stability. The first 50 TKA surgeries using the Sigma RP-F knee performed at the author's institution were matched to 50 rotating-platform knees for age, sex, body mass index, preoperative diagnosis, duration of follow-up, and preoperative ROM to determine the effect of design on postoperative ROM. The mean increase in active ROM in the Sigma RP-F group was 17 degrees, compared with 6 degrees in the rotating-platform group (P =.0011). The mean increase in active ROM in patients who had less than 120 degrees of preoperative motion was 27 degrees in the Sigma RP-F group, compared with 16 degrees in the rotating-platform group (P = .006). With the new P.F.C. Sigma RP-F design, greater ROM can be achieved independent of preoperative ROM.

Aged↗
PubMed2006

Patellar crepitation in the P.F.C. sigma total knee system.

Painless and painful patellar crepitation and patellar clunk syndrome represent a spectrum of peripatellar scar formation particular to posterior-stabilized knee components, although it may occur with cruciate-retaining designs as well. The formation of peripatellar inflammatory scar tissue is related to implant design and surgical technique, with microscopic and gross findings indicating varying degrees of inflammatory fibrous hyperplasia. These well recognized clinical entities have an incidence ranging between 1% and 5% in different series. The majority of patients with mildly painful or painless patellar crepitation will improve within 6 months to 1 year. In patients with more disabling symptoms such as catching, early intervention with open scar excision should be considered.

Aged↗
PubMed2005

What would you do? Case challenges in knee surgery.

These knee arthroplasty cases were presented to a panel of surgeon and they represent classic clinical problems: (1) indications for unicompartmental arthroplasty; (2) total knee arthroplasty after a high tibial osteotomy complicated by infection and extensor mechanism rupture; (3) neuropathic arthropathy; (4) posttraumatic osteoarthritis with extraarticular deformity; (5) degenerative arthritis in the young patient; (6) osteoarthritis with a valgus deformity, fixed flexion contracture, degenerative scoliosis, and leg length discrepancy.

Adult↗
PubMed2005

Experience with an all-polyethylene total knee arthroplasty in younger, active patients with follow-up from 2 to 11 years.

There are few modern reports that document the results of all-polyethylene (all-poly) tibial components in younger, active patients. The potential benefits of this design are the elimination of backside wear and lower implant cost than modular, metal-backed components. Nonetheless, since the mid 1980s, modular, metal-backed tibial trays have dominated the total knee arthroplasty market based on finite-element analysis studies that demonstrated superior force distribution compared with conventional all-poly components. As a result, backside wear has become an emerging problem and refocused design efforts on unitized components. Our clinical experience indicates that an all-poly tibial component fixed with cement can provide excellent performance and survivorship even in younger, active patients at intermediate follow-up.

Age Factors↗
PubMed2005

Total knee arthroplasty for severe valgus deformity.

BACKGROUND: In 1985, the senior author (C.S.R.) developed a new soft-tissue release technique to balance valgus knees to avoid unacceptably high rates of late-onset instability and the need for primary constrained implants. This report describes the soft-tissue release technique and its long-term results when performed in primary total knee arthroplasty in patients with a severe valgus knee deformity. METHODS: Four hundred and ninety consecutive total knee arthroplasties were performed by one surgeon between January 1988 and December 1992. In this group, seventy-one patients (eighty-five knees) had a valgus deformity of 10 degrees . Thirty-two patients (thirty-six knees) died, and four patients (seven knees) were lost to follow-up, leaving thirty-five patients (forty-two knees) followed for a minimum of five years. These twenty-seven women and eight men had a mean age of sixty-seven years at the time of the index operation. The technique included an inside-out soft-tissue release of the posterolateral aspect of the capsule with pie-crusting of the iliotibial band and resection of the proximal part of the tibia and distal part of the femur to provide a balanced, rectangular space. Cemented, posterior stabilized implants were used in all knees. Clinical and radiographic evaluations were performed at one, five, and ten years postoperatively. RESULTS: The mean modified Knee Society clinical score improved from 30 points preoperatively to 93 points postoperatively, and the mean functional score improved from 34 to 81 points. The mean range of motion was 110 degrees both preoperatively and postoperatively. The mean coronal alignment was corrected from 15 degrees of valgus preoperatively to 5 degrees of valgus postoperatively. Three patients underwent revision surgery because of delayed infection, premature polyethylene wear, and patellar loosening in one patient each. There were no cases of delayed instability. CONCLUSIONS: The inside-out release technique to correct a fixed valgus deformity in patients undergoing primary total knee arthroplasty is reproducible and provides excellent long-term results.

Aged↗
PubMed2004

A comparison of self-reported hip symptomatology in hip replacement patients and a population-based sample of medicare beneficiaries.

BACKGROUND: There exists variation over geographic areas in the use of total hip arthroplasty. This variation is not explained by the variation in the density per unit area of surgeons. The objective was to compare the severity of hip symptoms between a population-based sample of community-dwelling Medicare beneficiaries and a hospital-based sample of patients undergoing total hip replacement surgery. MATERIAL/METHODS: Population-based survey data on 113 community residents were compared to data from an independent sample of 157 hospital-based patients who underwent total hip replacement surgery, all of whom were 65 years and older. Severity of symptoms in both groups was rated using the Hip Rating Questionnaire (HRQ). RESULTS: The average population sample HRQ score was 63+/-9.0; overall arthritis impact 12+/-5, pain 14+/-6, walking 18+/-4, function 19+/-4. The average patient sample HRQ score was 56+/-14; overall arthritis impact 10+/-7, pain 11+/-4, walking 15+/-4, function 20+/-3. CONCLUSIONS: Community-dwelling individuals report symptoms as severe as patients who have undergone total hip arthroplasty. Further research is necessary to identify the reasons for the low incidence of treatment for those living in the community.

Activities of Daily Living↗
PubMed2004

Comparison of the PFC Sigma fixed-bearing and rotating-platform total knee arthroplasty in the same patient: short-term results.

This study compares the fixed-bearing PFC Sigma Total Knee Arthroplasty to the recently introduced rotating-platform version of the same design in 26 patients. At an average follow-up time of 46 months for the fixed-bearing side and 16 months for the rotating-platform side, no significant differences were found in terms of knee preference, knee pain, range of motion, overall satisfaction, or Knee Society scores (KSSs). No revisions, subluxations, dislocations, or infections were seen. Also no radiographic evidence of component loosening, osteolysis, or malalignment was found in any knee. The results of cementing the PFC Sigma rotating-platform, posterior-stabilized total knee show excellent patient satisfaction at 1 year and comparable clinical and radiographic results to the fixed-bearing version.

Aged↗
PubMed2004

Mastering the art of cemented femoral stem fixation.

Cemented femoral stem fixation is reproducible and provides excellent early recovery of hip function in patients 60 to 80 years old. The durability of fixation has been evaluated up to 20 years with 90% survivorship. Achieving a uniform cement mantle and minimizing polyethylene wear has been shown to reduce the incidence of fixation failure. This article describes the senior author's (C.S.R.) technique for cemented total hip arthroplasty with particular emphasis on the art of cemented femoral stem fixation and his experience with 3 different cemented stem designs over 30 years. The results of using this cement technique with a modern stem design with a surface roughness of 30 to 40 microinches have produced a 95% survivorship at 10- to 20-year follow-up in patients 60 to 80 years old.

Aged↗
PubMed2004

A prospective, randomized, double-blind study of smooth versus rough stems using cement fixation: minimum 5-year follow-up.

This prospective randomized double-blind study aims to evaluate the effect of surface finish of the cemented femoral stem in primary total hip arthroplasty. Between January 1996 and May 1997, a single surgeon prospectively implanted 244 primary THAs (237 patients) using cemented femoral stems with modified third-generation cement technique in selected patients. Patients were randomized to receive the Ranawat-Burstein prosthesis (Biomet, Warsaw, IN) with 1 of 2 finishes (smooth-Ra 17 or rough-Ra 170). At a minimum 5-year follow-up, no statistical differences were found between the 2 groups. One patient with a smooth stem underwent revision of the femoral component at 2 years secondary to aseptic loosening. There was no other evidence of radiographic loosening or osteolysis. As an isolated variable, surface finish does not appear to significantly influence results at mean follow-up of 6.5 years.

Aged↗
PubMed2004

In vivo kinematics for fixed and mobile-bearing posterior stabilized knee prostheses.

This is the first in vivo kinematic study to compare mobile-bearing with fixed-bearing prostheses in patients who had total knee arthroplasties. Femorotibial contact positions for 40 patients implanted with either a fixed-bearing or mobile-bearing prosthesis were analyzed using videofluoroscopy. Femorotibial contact paths were determined using a computer automated model-fitting technique. Nineteen of 20 patients in each group experienced posterior femoral rollback of their lateral condyles, with a mean of 3.6 and 3.7 mm for fixed-bearing and mobile-bearing prostheses respectively. Eighteen patients who had mobile-bearing prostheses and 17 patients with fixed-bearing knee prostheses experienced a normal pattern of axial rotation of 7.3 degrees and 4.1 degrees respectively. Eleven of 20 (55%) patients who had mobile-bearing prostheses implanted and eight of 20 (40%) patients who had fixed-bearing prostheses implanted did not experience femoral condylar lift-off. The remaining knees had condylar lift-off less than 2.4 mm for fixed-bearing prostheses and 1.7 mm for mobile-bearing prostheses, respectively. Patients who had mobile-bearing prostheses implanted experienced greater axial rotation and less condylar lift-off than patients who had fixed-bearing prostheses implanted. Both cruciate ligaments are sacrificed for the mobile and fixed-bearing total knee replacements. The results from the current study showed that, in both groups, the majority of patients experienced kinematics similar to those of a normal knee. However, the extent of lateral femoral condyle posterior rollback and the extent of axial rotation were less.

Humans↗
PubMed2004

Durability of the cemented femoral stem in patients 60 to 80 years old.

The importance of surface roughness and durability of fixation of the cemented femoral stem were examined. Three cohorts of patients approximately 60 to 80 years old, had cemented total hip replacements: Charnley (1978-1983) with first-generation cement technique consisting of canal-plugging and digital packing; Omnifit (1986-1991), and Ranawat-Burstein (R-B) Interlok (1992-1994) with modified third-generation cement technique. Kaplan-Meier survivorships, using failure for all causes (best case) were 90% +/- 5.1% at 20 years for the Charnley 95.1%+/- 3.4% at 15 years for the Omnifit and 99.5% +/- 0.5% at 9 years for the R-B Interlok prosthesis. Log rank test with paired data showed no significant differences between the groups for mechanical failure as an end point. Comparisons of survivorship curves for failure from all causes showed significant differences between the Charnley compared with the Omnifit and Interlok series respectively, with no significant differences between the Omnifit and R-B Interlok series. The cemented femoral stem, with a good cement mantle and surface roughness ranging from 30 to 150 microinches, did not show any significant differences in mechanical failure. Other variables such as stem centralization and low polyethylene wear need additional evaluation in survivorship of cemented total hip replacements.

Adult↗