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Biomedical subjects

H U Cameron

Publications and source records attributed to H U Cameron.

At least 19 recordsLinked to original sources
PubMed2003

Total hip arthroplasty in patients with deficient bone stock and small femoral canals.

Total hip arthroplasty in patients requiring very small femoral stems is a challenge because frequently deformity and inadequate bone stock, especially of the acetabulum, are also present. An analysis of 34 consecutive cases managed with a 9-mm distal diameter noncemented stem was performed. The mean patient age was 42.6 years and mean follow-up time was 7.8 years. Two patients were lost to follow-up at 4 and 6 years, and 1 patient had a fracture below the stem immediately after surgery, necessitating revision. These patients were excluded from analysis. Of the remaining 31 patients, 1 underwent revision for distal osteolysis leading to fracture. The Harris hip ratings for these patients were 58.1% excellent, 22.6% good, 16.1% fair, and 3.2% poor. Complications experienced included 1 femoral component that fractured but remains asymptomatic. Polyethylene wear of the very small acetabular components in 31% of cases is a cause for concern; 2 of these patients have required revision for this reason. The acetabular component was subsequently modified to allow thicker polyethylene.

Acetabulum↗
PubMed2001

[Modular shafts in hip prosthesis revision surgery].

The introduction of a proximally modular hip stem has greatly simplified difficult hip surgery. The long-term results of revision surgery indicate that the majority of revision cases can be handled with a proximal ingrowth implant, which helps speed bone recovery and simplifies re-revision if it is required. To date no particular downside has been noted as a result of the use of a modular stem.

Adult↗
PubMed1999

Fracture of the patella following total knee arthroplasty.

The charts of 21 patients (22 knees) with significant radiographic changes of the patella after total knee arthroplasty were reviewed. The average patient age was 73 years, and average follow-up after arthroplasty was 7.3 years. Lateral release, fat pad excision, quadriceps tendon release, and previous surgery were implicated in the etiology of fracture of the patella. Five cases had type 1 pattern (sclerosis, fragmentation, and no fracture), 5 cases had type 2 pattern (undisplaced fracture and fragmentation), and 12 cases had type 3 pattern (displaced fracture and fragmentation). Type 1 and 2 patterns required no surgical treatment and were rated good to excellent according to the Hospital for Special Surgery Disability Score Sheet. Patients with a type 3 pattern who did not undergo surgery were rated poor to fair, while patients with a type 3 pattern who underwent surgical treatment (patellectomy, removal of the patellar component, or excision arthroplasty for infection) were rated good. Patellectomy is the treatment of choice for patients with displaced fractures of the patella. A classification system for the pattern of patellar changes is proposed.

Aged↗
PubMed1998

Modified cups.

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.

Acetabulum↗
PubMed1998

Total joint replacement in multiplex congenita contractures: a case report.

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.

Adult↗
PubMed1997

Prognostic factors in the outcome of supracondylar femoral osteotomy for lateral compartment osteoarthritis of the knee.

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.

Adult↗
PubMed1997

Total knee replacement after supracondylar femoral osteotomy.

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.

Adult↗
PubMed1997

Hinge total knee replacement revisited.

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.

Adult↗
PubMed1997

Osseointegration & stress shielding.

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.

Adult↗
PubMed1997

HA versus grit blast tibial components in total knee replacement.

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.

Alloys↗
PubMed1996

Results of total knee arthroplasty following takedown of formal knee fusion.

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.

Aged↗