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Biomedical subjects

H U Cameron

Publications and source records attributed to H U Cameron.

At least 91 records · Page 5Linked to original sources
PubMed1987

The patellar meniscus in total knee replacement.

Theoretically, because most patellar replacements are convex polyethylene structures subjected to high loads, considerable wear should occur. This has not been reported. A review of knee revisions had been carried out. The patella has been resurfaced on 12 occasions. It was revised on five occasions, and gross wear was seen in three of these cases, in all of which the patella had dislocated. The patella in all cases was surrounded by a meniscus of dense fibrous tissue. A small wear facet in the exposed area was present. This suggests that patellar articular surface geometry may not be critical as far as wear is concerned.

Humans↗
PubMed1987

Stress-relief osteoporosis of the anterior femoral condyles in total knee replacement. A study of 185 patients.

A study has been conducted to examine anterior femoral condylar osteoporosis. A series of 65 ICLH knees with a more than four-year follow-up and a series of 120 Tricon P knees were examined radiologically. It was found that almost all cases showed anterior femoral condylar osteoporosis beginning at three months and stabilizing at two years. It was more severe in those with rheumatoid arthritis than in those with osteoarthritis. This type of osteoporosis can be prevented by using a layer of cement more than 7 mm thick or by using reinforcing screws in the condyles. Femoral component loosening leads to regression of the changes. This osteoporosis does not give rise to for revision arise in a case of this type, bone should be available for grafting the anterior femoral condyles.

Adult↗
PubMed1987

Results of total hip arthroplasty without trochanteric osteotomy following hip fusion.

Other than the results of the Charnley group, using a transtrochanteric approach, there is little in the literature regarding the techniques and results of total hip arthroplasty following hip fusion. Thirteen cases carried out via an anterior Smith-Peterson approach have been performed by the senior author over the last few years. These cases have been studied to determine pitfalls and outcomes using this method. At one year, seventy-five percent of the cases became Trendelenberg negative. The average range of flexion at one year was 88 degrees and the Harris Hip Score was 2 poor, 2 fair, and 9 good or excellent. Retrospectively, one patient would rather not have had surgery. Nerve and vessel damage was not a problem and neither was myositis ossificans. Where possible, existing hardware was removed six months prior to arthroplasty. However, three femoral shaft splits occurred where noncemented femoral components were used. While it is a technically demanding exercise, the results of total hip replacement following hip fusion are acceptable.

Adult↗
PubMed1987

Role of total knee replacement in failed knee fusions.

The author describes his technique and the results of total knee replacement in four patients who already had fused knees. In two, the patella was present so a semiconstrained prosthesis was used, but in the other two a stabilized knee prosthesis was used because the patella was absent. In the first case, lack of experience with the technique led to failure of the prosthesis and revision was necessary, but in subsequent cases the patients have done well. Quadriceps control was not a problem. Range of movement improved slowly over the first year. The author concludes that disassembly of knee fusion is possible and gives acceptable results.

Aged↗
PubMed1986

Six-year results with a microporous-coated metal hip prosthesis.

In an attempt to obtain bone ingrowth into a microporous-coated metal implant, a hip prosthesis with a pore width of approximately 50 microns was used in 34 cases. Implants revised up to six years following surgery have all shown fibrous tissue ingrowth only. Neither sinkage nor osteoporosis was observed. Revision was made difficult by the presence of a collar obstructing access to the proximal junction between the implant and bone.

Aged↗
PubMed1986

Anteromedial displacement of the tibial tubercle for patellofemoral arthralgia.

Anterior and medial repositioning of the tibial tubercle (anteromedialization) reduces patellofemoral pressure and corrects patellar malalignment. Over the last 6 years this simple procedure was carried out on 53 knees in patients who had no athletic inclinations. The average age was 40.4 years. Follow-up was at least 1 year. A rating system was developed and overall the results were 65.9% excellent, 15.9% good, 11.4% fair and 6.8% poor. In the over-45 age group, the results were 57.1% excellent, 28.6% good, 14.3% fair and none poor. The complication rate was relatively low (18.7%). This procedure appears to be satisfactory for patellofemoral arthralgia when malalignment is present, particularly in the elderly.

Adult↗
PubMed1984

The influence of etiology on the results of coccygectomy.

The results of coccygectomy for coccygodynia seem not to have been correlated with etiologic factors and were investigated in 48 cases (10 men and 38 women) with an average follow-up period of seven years. The following four etiologic groups were designated: I, direct trauma; II, spontaneous in origin; III, coccygodynia associated with spinal surgery; and IV, postpartum. Groups I and IV had a 75% recovery rate from pain and Group II had a 58% recovery rate. No satisfactory results were obtained in Group III. The incidence of infection was 16.6%. Few satisfactory results were obtained in cases of deep infection. While this operation is effective in many cases, it is seldom successful for pain associated with lumbar disc disease requiring lumbar laminectomy and spine fusion. Prophylactic antibiotic therapy is clearly indicated.

Adolescent↗
PubMed1984

Snapping scapulae: a report of three cases.

Snapping scapula or retroscapular pain is uncommon, and few cases require surgical intervention. In three cases the symptoms were such as to eventually require surgery. No obvious cause was found but excision of the 2 cm of the medial scapular border resulted in prompt and permanent pain relief. Why this should be so is a mystery.

Adult↗
PubMed1984

Total knee arthroplasty following patellectomy.

Patients with prior patellectomy may continue to experience pain and instability following total knee arthroplasty. Seventeen such cases were found, 14 of which were available for study. One knee was fused for deep infection. Of the remaining 13, six were revised for continuing pain. The final results correlated to the intrinsic stability of the prosthesis. All hinges (5 cases) had good results, one of two unlinked hinges had good results, and two of six semiconstrained prostheses had acceptable results. Since the patellar mechanism with the cruciates functions as a four-bar linkage to ensure functional anteroposterior stability, one of these linkage systems must remain intact. If both are destroyed, a prosthesis with inherent anteroposterior stability should be used.

Aged↗
PubMed1982

The results of early clinical trials with a microporus coated metal hip prosthesis.

In an attempt to find a better method of attaching a prosthesis to bone, a microporous coating system, with a pore width of approximately 50 microns was chosen for evaluation. A microporous coated Austin-Moore type prosthesis was inserted into 34 patients, and the results were studied for a three-year period. Four cases required reoperations, and ten cases demonstrated radiolucent lines around the prosthesis suggesting that bone ingrowth had not occurred. This article analyzes the reasons for failure of ingrowth and suggests modifications in the prosthesis design and postoperative management that hopefully will be effective.

Adult↗
PubMed1982

Femoral head migration after single assembly total hip arthroplasty.

One of the problems of a solid head Moore type prosthesis is acetabular migration. The compound bearing single assembly (Bateman) total hip arthroplasty is supposed to decrease the incidence of this complication. A series of 160 hips reviewed to determine the validity of the single assembly total hip suggested that intrapelvic protrusion developed only in the presence of sepsis. In the present of a dysplastic acetabulum; however, superior migration was a common occurrence unless the acetabulum was significantly deepened.

Adult↗
PubMed1982

The patella in total knee arthroplasty.

Uncertainty still exists as to the necessity to resurface the patella in total knee arthroplasty. In a series of 77 ICLH knee arthroplasties there were 12 bilateral cases which had a prior patellar resurfacing on one side and a patelloplasty on the other. The results of those who had a patellar resurfacing were slightly better, but only three patients could tell the difference in their knees. Incidence of patellar fracture following resurfacing was much higher than that following patelloplasty.

Fractures, Bone↗
PubMed1982

Biologic fixation and bone modeling with an unconstrained canine total knee prosthesis.

To study the effects of dynamic loading on biologic fixation, an unconstrained type of prosthesis was designed for total replacement of the knee joint of dogs. The femoral component was fabricated from cast cobalt-based surgical alloy. The tibial component was fabricated from surgical grade, ultra-high molecular weight, high density polyethylene. Both components were designed for initial stabilization at surgery by mechanical interlock with bone. In addition, the bone-interfacing surface of the metal component was made porous and the stem of the polymer component was grooved to permit the subsequent ingrowth of tissue. Knee arthroplasty was performed on a total of six beagles. The prostheses were monitored for periods of 20 months and demonstrated an overall excellent stability and functionality. Each tibial component became stabilized by the formation of a thin, surrounding shell of osseous tissue. Interposed between this bone and the implant was usually a thin layer of fibrous tissue, suggesting micromovement during loading. Each femoral component became solidly fixed by bone growth into the porous surface. The altered stress state in the region of the implant eventually resulted in reactive bone modeling, with both bone formation and resorption occurring along the length of the implant.

Animals↗
PubMed1982

Failure in total knee arthroplasty: mechanisms, revisions, and results.

Of 700 prosthetic knees inserted during the period from 1969 to 1978, 94 failed; 19 of the failures occurred due to infection. Other obvious mechanisms of failure were wear debris sy novitis, ligament rupture, and patellar dislocation. The majority of prosthetic loosenings occurred on the tibial side. There were five mechanical factors of such loosening: tilt and sink; compression; torsion; toggle; and a combination of these factors. Excluding those who died or were lost to follow-up, the results of revision were 37% good or excellent; 60% fair or poor; and 3% failure. To some extent the results were prosthesis dependent; the semiconstrained prosthesis had a good result in 48%, unlinked hinges a good result in 24%, and a true hinge a good result in 21%. The results in infected cases were poor; of five prosthetic revisions, only one was good. Fusion was found difficult to achieve; of 11 attempts, only six obtained solid fusion. Four amputations were performed, all for infection in hinged knee replacements.

Aged↗