Chitranjan S. Ranawat

A comparison of four models of total knee-replacement prostheses

Twenty-nine knees with unicondylar, sixty-four with duocondylar, fifty with Guepar, and fifty with geometric prostheses were studied. The follow-up ranged from two to three and one-half years. The unicondylar prosthesis was used in the mildest cases and gave the least complications, but the quality of results was not superior to that achieved with the other prostheses. The duocondylar model was best suited for knees with rheumatoid arthritis and mild deformity. The geometric prosthesis was the best condylar prosthesis for osteoarthritis with moderate to severe deformity, but gave the worst results in knees with rheumatoid arthritis. The Guepar prosthesis was used in the worst knees and gave the best results, but it had the highest infection rate and was the most difficult to salvage. A radiolucency was observed in about 60 per cent of the condylar replacements around the tibial component and in 45 per cent of the Geupar replacements around the femoral component. The significance of this cannot yet be determined but it suggest that the fixation may not be ideal. In all types, residual pain was most frequently attributed to the patellar compartment. Patellectomy was not a solution.

Results of revision for mechanical failure after cemented total hip replacement, 1979 to 1982. A two to five-year follow-up.

From January 1979 to February 1982, 143 patients (seventy-nine women and sixty-four men) with 146 uninfected cemented total hip arthroplasties had revision cemented hip arthroplasty at The Hospital for Special Surgery for what was considered to be mechanical failure. The average age of the patients at primary arthroplasty was 56.1 years and at revision, 62.1 years. Loosening of the femoral component before revision correlated with varus positioning in 50 per cent of the hips, inadequate cement in 34 per cent, and a relatively young age in 16 per cent. The average age of the patients (fifteen hips) with a loose femoral component that had been placed in a neutral or valgus position with good cementing technique was 48.2 years at the time of primary arthroplasty. Loosening of the acetabular component was attributed to high placement of the cup in 41 per cent, inadequate bone in 18 per cent, a vertical orientation of the opening of the cup in 7 per cent, and poor cementing technique in 3 per cent. Complications associated with revision included perforation of the femoral cortex in 13 per cent, postoperative deep infection in 3.4 per cent, postoperative dislocation in 8.2 per cent, trochanteric complications in 6.2 per cent, and sciatic palsy in 0.7 per cent. Of the 139 hips that were followed for an average of 3.6 years (range, two to five years) after revision, the results were excellent in 59 per cent, good in 7 per cent, fair in 16 per cent, and poor in 18 per cent. After revision of the 139 hips, 29 per cent showed progressive radiolucencies; 18 per cent, femoral subsidence; and 9 per cent, acetabular migration. Definite mechanical failure after revision was identified in 15.8 per cent of the hips. These failures were due to loosening in 12.2 per cent of the hips, femoral fracture in 2.2 per cent, and disabling dislocation in 1.4 per cent. At the time of follow-up, twelve hips (8.6 per cent) had been revised a second time: six (4.3 per cent) for loosening of one or both components, three (2.2 per cent) for femoral fracture, and three (2.2 per cent) for infection. Mechanical failure and progressive radiolucencies were associated with poor quality of bone (p less than 0.001) and inadequate anatomical reconstruction (p less than 0.03).

Cervical spine fusion in rheumatoid arthritis.

Spinal fusion for deformity of the cervical spine was done in thirty-three patients with rheumatoid arthritis. The average follow-up was three years. The deformities present were atlano-axial subluxation, superior migration of the odontoid process into the foramen magnum, and subaxial subluxation of the vertebral bodies. We devised a classification of the pain and the neural involvement in these patients and a new method of measuring superior migration. The surgical procedures for treating instability, intractable pain, or neural involvement, or a combination of the three, were: (1) a Gallie fusion of the first and second cervical vertebrae for atlanto-axial subluxation, (2) a fusion of the occiput and the second cervical vertebra for superior migration of the odontoid process, and (3) a posterior fusion for subaxial subluxation. The occiput was included in the fusion if superior migration of the odontoid process was demonstrated. The results show that four of five patients who had an anterior fusion had no improvement. Twenty-five patients had posterior fusion; in seventeen the condition was improved, in five there was improvement, and in three the condition was worse. Of nineteen patients with neural involvement, the condition was improved in eight, it was unchanged in seven, and it was made worse in two. There were three postoperative deaths and six additional unrelated deaths within two years of surgery. There were five pseudarthroses.

Long-Term Results of the Total Condylar Knee Arthroplasty: A 15-Year Survivorship Study

This study reports the 15-year survivorship of 112 consecutive Total Condylar knee arthroplasties that have been followed since 1974. Two endpoints were chosen for survivorship: (1) Revision attributable to septic or aseptic loosening or malalignment. (2) Revision or roentgenographic evidence of component loosening. Life table analysis reveals a 94.1% clinical survivorship at 15 years, with an 90.9% survivorship when roentgenographic failures are included. There were five revisions: one for infection, one for instability, and three for tibial loosening. In addition, two tibiae and one patella were considered roentgenographically loose, but were not symptomatic. As of May 1992, 34 patients with 48 knees are known deceased, 15 knees are lost to follow-up evaluation, and 49 knees are available for clinical evaluation. Follow-up data was available on 62 knees for greater than 11 years. Ninety-two percent had good or excellent results, with 1.6% fair and 6.5% poor. Average range of motion was 99 degrees. The average Hospital for Special Surgery knee score was 85. Roentgenographic study revealed lucencies around 72% of tibiae, but only two components were loose. There was a correlation between body weight and the presence of radiolucencies, and patients who weighed more than 80 kg had the lowest survivorship at 15 years: 89.2% clinical survival and 70.6% clinical plus roentgenographic survival. Total Condylar knee arthroplasty has a 94.6% clinical survival at 15 years, with predictably good clinical results.

The total condylar knee prosthesis. A report of two hundred and twenty cases.

The total condylar knee prosthesis is a non-hinged surface replacement which can be used for almost all knee deformities. This report discusses the first consecutive 220 arthroplasties in 183 patients. Follow-up time was three to five years. Before operation eighty-six knees had more than 10 degrees of fixed varus deformity and thirty-one knees had more than 10 degrees of fixed valgus deformity. All patients were assessed using The Hospital for Special Surgery scoring system. Of the total of 220 knees, 137 (62%) were rated excellent; sixty-one (28%), good; ten (4.5%), fair; and twelve (5.5%), poor. Of 139 osteoarthritic knees, 93% were rated excellent or good. Complications included three deep infections and four cases of posterior subluxation. The over-all reoperation rate was 3.6%.

In vivo anteroposterior femorotibial translation of total knee arthroplasty: a multicenter analysis.

A study was conducted to determine in vivo femorotibial contact patterns for subjects having a posterior cruciate retaining or posterior cruciate substituting total knee arthroplasty. Femorotibial contact of 72 subjects implanted with a total knee replacement, performed by five surgeons, was analyzed using video fluoroscopy. Thirty-one subjects were implanted with a posterior cruciate retaining total knee replacement with a flat polyethylene posterior lipped insert, 12 with a posterior cruciate retaining total knee replacement with a curved insert, and 29 with a posterior cruciate substituting total knee replacement. Each subject performed successive deep knee bends to maximum flexion. Video images at 0°, 30°, 60°, and 90° flexion were downloaded onto a workstation computer. Femorotibial contact paths were determined for the medial and lateral condyles using an interactive model fitting technique. Femorotibial contact anterior to the tibial midline in the sagittal plane was denoted as positive and contact posterior was denoted as negative. Analysis of average femorotibial contact pathways of both posterior cruciate retaining designs revealed posterior femorotibial contact in full extension with anterior translation of femorotibial contact commonly observed in midflexion and terminal flexion. In posterior cruciate substituting designs, anterior femoral translation was seen medially at 30° to 60° flexion but rarely was observed laterally. Posterior femoral rollback laterally from full extension to 90° flexion was seen in 100% of subjects implanted with a posterior cruciate substituting total knee replacement, versus 51.6% (posterior lipped polyethylene insert) and 58.3% (curved insert) of those with a posterior cruciate retaining total knee replacement. Data from this multicenter study are remarkably similar to previous fluoroscopy data from a single surgeon series, showing a lack of customary posterior femoral rollback in both posterior cruciate retaining designs, and conversely showing an average anterior femoral translation with knee flexion. Posterior femoral rollback, less than in normal knees, routinely was observed in posterior cruciate substituting total knee arthroplasty, attributed to engagement of the femoral component cam with the tibial post. The abnormal anterior femoral translation observed in posterior cruciate retaining total knee arthroplasty may be a factor in premature polyethylene wear observed in retrieval studies.

A prospective study of the progression of rheumatoid arthritis of the cervical spine.

This prospective study was begun in 1974 to determine the progression of rheumatoid ar thritis of the cervical spine. Of 163 patients with com plaints about the cervical spine followed in the Ar thritis Clinic, 106 were available for study five years later. At the start of this study, forty-six (43 per cent) of these 106 patients already had radiographic evidence of rheumatoid involvement of the cervical spine, con sisting of atlanto-axial subluxation in twenty-eight (61 per cent), atlanto-axial subluxation combined with subaxial subluxation in nine (20 per cent), and subaxial subluxation alone in five (1 1 per cent). The remaining four patients (8 per cent) had combinations of these findings together with superior migration of the odon toid process. At the end of the study, seventy-four (70 per cent) of the patients had radiographic evidence of cervical involvement, primarily of the combined type. Twenty-one patients died during the period of follow-up. None of the known causes of death could be attributed to disease of the cervical spine. Three features of rheumatoid cervical disease were evaluated: pain, neural involvement, and radiographic abnormalities. Although all three features were pro gressive, radiographic deterioration was a more prom inent feature than progressive neural dysfunction. At the final evaluation, the disease in twenty-seven (36 per cent) of the patients was noted to have progressed neu rologically while in sixty patients (80 per cent) it had progressed radiographically. Pain was the only feature of the disease that showed any tendency to improve. The development of subaxial subluxation or superior migration of the odontoid process in a patient with pre-existing atlanto-axial subluxation was found to be a bad prognostic sign.

Long-term results of revision total hip replacement. A follow-up report.

The results of 110 revision total hip replacements performed for aseptic failure, with an average follow-up of 3.4 years, were reported in 1982. We were able to continue to follow ninety-nine of these patients for an average of 8.1 years (range, five to 12.5 years). With this longer follow-up, we found that twenty-nine (29 per cent) of these revised arthroplasties have since failed. Most of the failures after 1982 occurred in the hips that were known to have a progressive radiolucency at the time of the first evaluation. We concluded that there is an increased failure rate with longer follow-up of revision total hip replacement, and that progressive radiolucency at an interface indicates a poor prognosis for the arthroplasty.

The patellofemoral joint in total condylar knee arthroplasty. Pros and cons based on five- to ten-year follow-up observations.

In this report, 100 knees in 77 patients, with an average age of 65, were followed for a period between five and 10 years. Rheumatoid arthritis was the diagnosis in 43 patients and osteoarthritis in 34 patients. The majority had varus, valgus, and biplane deformities. Twenty-one patients underwent bilateral procedures; all but one had patellar replacement. Over 90% of the knees were rated good to excellent according to The Hospital for Special Surgery Knee Disability Score Sheet. Of the 34 osteoarthritic patients (40 knees), 24 or 71% could walk ten blocks and beyond. Ten patients, or 29%, could walk between one and ten blocks. Further ambulation was restricted only by overall poor health and age (most were 74 years of age or older). Twenty-four patients, or 71%, could ascend and descend stairs without support, while six (18%) relied on bannister support when descending stairs. Four patients (11%) required bannister support for both ascending and descending stairs. Among the complications seen in this series were one loose patella and another with osteonecrosis of the anterior surface. No dislocations occurred, but 14 patellae showed tilt on skyline view roentgenograms, indicating a tight lateral retinaculum. In view of the good to excellent results achieved in the majority of patients, and the low morbidity associated with replacement, it is recommended that the patellofemoral joint be replaced in the course of total knee arthroplasty. When careful attention is paid to technical details, this procedure improves the quality of the arthroplasty.

Total hip arthroplasty in protrusio acetabuli of rheumatoid arthritis.

Thirty-five total hip arthroplasties done in twenty-five patients with protrusio acetabuli secondary to rheumatoid arthritis were reviewed. There was an average follow-up of 4.3 years, with a range of three to seven years. The results were rated as excellent or good in 66 per cent, fair in 26 per cent, and poor in 8 per cent. Although 100 per cent demonstrated cementbone interface demarcation around the acetabular component, only 10 per cent showed progression of the line of demarcation to two millimeters and one had acetabular loosening with migration. Eight per cent showed femoral loosening or subsidence; 8 per cent, calcar resorption; and 6 per cent, a receding cortex with cystic changes. Twenty-three per cent had nonunion of the greater torchanter after trochanteric osteotomy. Type-III cement-bone interface demarcation was present around the acetabular component was positioned one centimeter superiorly or medially beyond the anatomical position, as estimated by the method described. In thirteen hips in which the acetabular component was positioned within five millimeters of the anatomical position, no Type-III demarcation was present. Better fixation and position of the acetabular component is achieved by the use of a bone graft or a special titanium perforated-sheet mesh, or both, or by an acetabular shell. The use of three wires improved trochanteric fixation.