Biomedical subjects
Publications and source records attributed to H U Cameron.
Late results of structural allografting of the acetabulum are quite variable. In order to reduce or avoid the necessity for bone grafting, some modified cups have been developed. The deep cup with or without a lateralized polyethylene liner reduces the problem of the protrusio socket. Oblong or bilobed ingrowth cups significantly reduce the need for grafting of the roof-deficient acetabulum. Constrained or capture polyethylene liners are useful in the unstable hip.
Explore the source record for details and available documents.
A 34-year-old man with multiplex congenita contractures underwent replacement of 2 hips and 1 knee. Even though a good range of movement was achieved at surgery and intensive physiotherapy, his joints returned to their preoperative status within 2 years. This outcome suggests that total joint replacement has little to offer the patient with multiplex congenita contractures who has immobile joints.
Explore the source record for details and available documents.
OBJECTIVE: To identify the demographic and operative factors that determine outcome in supracondylar femoral osteotomy for lateral compartment osteoarthritis of the knee. DESIGN: Clinical and radiologic review of a nonrandomized, consecutive one-surgeon series. SETTING: A university-affiliated, elective surgical referral centre. PATIENTS: Forty-nine consecutive patients with unicompartmental osteoarthritis of the knee, involving the lateral compartment, and of sufficient severity that the alternative surgical procedure would be total knee replacement. INTERVENTION: Supracondylar varus osteotomy stabilized with a blade plate. MAIN OUTCOME MEASURES: Knee function measured by the Knee Society Score and time to conversion to total knee replacement. RESULTS: A Knee Society Score greater than 80 was obtained in 81% of patients, but in the function portion of the measurement only 30% had a similar score. After discarding the patients who died, life-table analysis demonstrated the predicted survival before conversion to total knee replacement to be 87% at 7 years. There was no correlation with patient age or sex, femorotibial angulation, amount of correction or time after the intervention. Removal of the fixation device improved the clinical result. CONCLUSION: The role of supracondylar femoral osteotomy remains poorly defined, but the procedure can delay total knee replacement for considerable time in appropriate patients.
Surgically produced deformities around the knee may influence the outcome of total knee replacement (TKR). This article reviews eight cases of TKR following supracondylar varus femoral osteotomy. While in each case, the distal femur was offset medially on the femoral diaphysis, the outcome as measured by the clinical result and the alignment was uniformly excellent. It is concluded, therefore, that supracondylar varus femoral osteotomy does not affect the subsequent TKR.
OBJECTIVE: To determine if aseptic loosening is a major problem in hinge total knee replacement. DESIGN: A cohort study. SETTING: A university-affiliated institute, specializing in elective orthopedic surgery. PATIENTS: Fifty-eight patients, mainly those requiring revision, in whom the conditions were such that it was felt only a totally constrained implant was appropriate. In 7 patients the implant was press-fitted; in the remainder it was cemented. Five patients required fusion or revision, and 8 died less than 2 years after implantation, leaving 45 for review. Follow-up was 2 to 13 years. INTERVENTION: Total knee replacement with a Guepar II prosthesis. MAIN OUTCOME MEASURES: Radiolucency determined by the Cameron system and clinical scoring using the Hospital for Special Surgery system. RESULTS: Of the cemented components, 91% of femoral stems were type IA (no lucency), 9% were type IB (partial lucency), with no type II or III lucency. Tibial lucency was 87% type IA and 13% type IB, with no type II or III lucency. Of the noncemented components, 58% of femoral components were type IA and 42% type IB. Tibial lucency was 71% type IA and 29% type IB. Lucency was mainly present in zones 1 and 2 adjacent to the knee. Clinical rating was 18% excellent, 20% good, 20% fair and 42% poor. Postoperative complications included infection (13%), aseptic loosening (7%), quadriceps lag (16%) and extensor mechanism problems (16%). CONCLUSIONS: Aseptic loosening is an uncommon problem in hinge total knee replacement. The complication rate in cases of sufficient severity as to require a hinge replacement remains high. Current indications for a hinge prosthesis are anteroposterior instability with a very large flexion gap, complete absence of the collateral ligaments and complete absence of a functioning extensor mechanism.
Forty-two patients with a flexible distal non-cemented grit-blast hip stem have been examined to see if distal osseointegration (OI) had occurred. The minimum follow-up was 5 years. The definition of distal osseointegration was "the exhibition of distal bone hypertrophy with proximal bone atrophy with no radiolucency in a clinically stable situation". Osseointegration was noted in 28.6%. It was seen more commonly in older females with greater canal fill, especially in the lateral x-ray. A control group in which the distal end of the stem was polished showed virtually no osseointegration. It appears therefore that with the simple expedient of polishing the distal stem, osseointegration in this zone can virtually be abolished.
A comparison of 127 HA coated with 70 grit blast titanium noncemented tibial components in TKRs has been carried out. Clinically the results were indistinguishable. Radiolucency was significantly less in the HA coated components suggesting improved fixation. At 5 years, loosening and wear have yet to be seen. These results suggest that HA may be a useful adjunct to noncemented component fixation in total knee replacement.
Seventeen cases of knee fusion takedown with follow-up periods of 1 to 10 years have been reviewed. Two patients were re-fused for patellar tendon loss and sepsis. One had a chronic low-grade infection but refused re-fusion. Two patients who required immobilization for the first 10 days following total knee arthroplasty had a range of flexion of 35 degrees only. The mean range of flexion in the other patients in 84 degrees. Using The Hospital for Special Surgery rating, 29.4% scored excellent, 29.4% good, 17.6% fair, and 17.6% poor, including the two patients refused. Complications were found in nine patients (53%), six of which were resolved with further surgery. All patients preferred the mobile knee, but the complication rate is so high that the authors remain ambivalent about this procedure.
Explore the source record for details and available documents.
Few studies have examined the relationship between the severity of congenital dysplasia of the hip (CDH) and the clinical outcome of total hip arthroplasty. The authors have used a prospective design to study this question, using the Crowe grade to assess the severity of CDH. There were 71 patients with CDH operated on using the S-ROM total hip (Joint Medical Products, Stamford, CT); the control group was composed of 22 patients without CDH operated on using the same implant during the same period as the CDH patients. The patients with mild CDH did not have a different outcome from the patients without CDH with respect to Harris hip score or limp. The higher the Crowe grade, the more complications occurred. It was also found that the patients in whom the true acetabulum was not used had a significantly higher incidence of limp.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
OBJECTIVE: To determine the outcome of total knee replacement using a posterior cruciate-substituting knee prosthesis in patients who have undergone previous patellectomy. DESIGN: A cohort study, with a follow-up ranging from 2 to 9 years. SETTING: A university-affiliated institution specializing in elective orthopedic surgery. PARTICIPANTS: Sixteen patients with arthritis of the knee who had had patellectomy. All agreed preoperatively to a prolonged postoperative follow-up. INTERVENTION: A cemented posterior cruciate-substituting knee replacement. MAIN OUTCOME MEASURES: Stair climbing ability, the Hospital for Special Surgery knee rating system for clinical results and a radiologic rating using a zonal system. RESULTS: Clinical rating was 69% good or excellent. Eighty-one percent of patients could use the replaced knee as the lead leg on stair climbing. Minor radiolucency, mostly single zone only, was found. Two patients required revision because of pain, but no obvious reasons for this pain were found at operation. CONCLUSION: In the absence of a patella, a posterior cruciate-substituting prosthesis gives reasonable results.
Explore the source record for details and available documents.
Explore the source record for details and available documents.