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I C Clarke

Publications and source records attributed to I C Clarke.

43 records · Page 3Linked to original sources
PubMedDate not supplied

THARIES surface replacements: a review of the first 100 cases.

The first 100 cases of the 135 THARIES surface replacement procedures with 4--32 months follow-up, are evaluated in terms of clinical results, radiographic information and complications. The short but detailed follow-up suggests that this procedure was an excellent alternative for the younger and more active population. The overall hip ratings (pain, walking and function) and range of motion are comparable to that of stem-type total hip replacements. When the THARIES and conventional hip results are further compared in 34 patients matched by sex and age for 3 major etiological groups (osteoarthritis, osteonecrosis and congenital hip dysplasia), the interim results are essentially comparable for both types. Three cases in the first 100 have required revision. One patient (no. 1) with osteoporosis, chondrolysis and arthrofibrosis following slipped capital femoral epiphysis had loose femoral and acetabular components 24 months postoperatively. He was revised to a T-28 hip replacement. The polyethylene socket in another patient (no. 4), the first dysplastic hip in this series, was 20 nm uncovered superiorly, became loose and was revised 9 months postoperatively. Now 15 months postoperative with a more medial THARIES acetabulum, the patient continues to have a good result. Another patient (no. 12) with bilateral dysplastic hips became progressively more disabled due to heterotopic bone, which was then excised 18 months postoperatively. Radiographic studies of the THARIES sockets demonstrate radiolucent zones at the cement-bone interfaces of the acetabulum in 88 cases, partial in 51 and complete in 37. Three hips were currently considered to have evidence of progressive socket loosening but are active and asymptomatic. There have been no femoral neck fractures in this series which we attribute to the custom fitting ability inherent in the range of components, the reaming protocol and the various remodelling guides. There have been no prosthetic breakages, subluxations, dislocations or sepsis. The complications observed in this series are minor and comparable to that of many other total hip arthroplasty operations. Nerve palsy and trochanteric separation have not been major problems although one existing peroneal nerve dysfunction and one trochanteric migration emphasize the need to minimize these complications by careful handling of the operative leg, and an accurate trochanteric reattachment technique.

Adolescent↗
PubMedDate not supplied

The acetabular cement-bone interface in experimental arthroplasties in dogs.

Increased clinical loosening of total hip arthroplasty acetabular components has been noted in patients with long follow-up and in young active individuals. Evaluation of the acetabular cement-bone interface has been limited to a few human cadaveric specimens and to canine studies in which the data are difficult to interpret. The effects of cement fixation of the acetabular component were investigated in serial observations in 21 dogs with hip surface replacements. The postoperative survival time before evaluation was from two to 46 weeks. Twenty animals were clinically normal before autopsy. Analytic techniques used to examine acetabular fixation included the use of epoxy-embedded specimens to preserve the cement-bone interface and conventional histologic sections. After two weeks, no direct contact between the cement and bone was seen. A correlation between the adequacy of cement fixation and interface membrane thickness was found. Poor acrylic fixation resulted in thick membranes up to 2 mm thick and horizontal trabeculation of the interface woven bone. Good cement intrusion led to a thinner, almost minimal membrane two to three cells in thickness.

Acetabulum↗
PubMedDate not supplied

UCLA anatomic total shoulder arthroplasty.

The UCLA total shoulder arthroplasty was designed to mobilize the shoulder joint in order to permit normal anthropometric range of motion and durable long-term fixation of the components. The prosthesis is fundamentally nonconstrained for the usual arthritic conditions, currently with four sizes of femoral and glenoid components. For patients with deficient and irreparable rotator cuffs, additional restraint may be effected by using a superior glenoid subacromial rim. The first 11 patients have been followed for 1 1/2 to 3 1/2-years; relief of pain has been complete in all but two patients. The function and range of motion results were related to the status of the rotator cuff; five patients achieved excellent results, including two with osteoarthritis who had near normal function. Patients with deficient rotator cuffs achieved functional use of the extremity but without full range of motion. Functionally, in addition to the five patients who were rated excellent, two were rated as being good, three fair, and one poor. In addition to five with excellent range of motion, there were three good and four fair ratings. Two patients, one with grossly deficient musculature caused by a gunshot wound and a second who was posttrauma required revision surgery with a subacromial glenoid prosthesis. This prosthesis is now frequently utilized if muscles and rotator cuff are deficient at the primary surgery, in order to provide additional restraint. Determination of the efficacy of hooded components will require further follow-up. The additional size ranges and components together with improved instrumentation have greatly facilitated recent surgery.

Adult↗
PubMedDate not supplied

Improved methods for quantitative radiographic evaluation with particular reference to total-hip arthroplasty.

The range of magnification factors in 40'' and 72'' radiographs were calibrated using three simple mathods. The relationship between X-ray source to cassette distance, object to cassette distance and magnification factors was determined experimentally for both 40'' and 72'' radiographs. The resulting nomogram showed that: (1) there was no significant magnification difference between centered (AP-hip) and offset (AP-pelvis) radiographs; (2) magnification factors of 40'' films were twice those of 72'' films for the same object to cassette distances; and (3) due to the smaller magnification range of 72'' films (1 to 13%) compared to 40'' films (1 to 26%) there was less chance of error in determining magnification factors for the larger film distances. The skin radiation dosage for the patient was similar in both procedures. Magnification factors were also calculated from 414 A-P radiogrphs of total-hip prosthesis, using the femoral ball as a calibration standard. This provided magnifications of 20 per cent +/- 6(2SD) for 40'' films and by extrapolation on the nomogram gave corresponding values of 10 per cent +/- 3 for the 72'' films. The associated hip to cassette distances (L), also obtained from the nomogram, varied from 125 to 205 mm, average 165 mm. In subsequent clinical trials using 72'' films, it was possible to represent the patients as either small (L less than 145 mm) medium (145 less than or equal to L less than or equal to 185 mm) or large (L greater than 185 mm) with corresponding magnification factors of 8, 10 and 12 per cent, respectively. The error with this simplification was still within +/-21/2 per cent. For 40'' films the corresponding magnification factors for small, medium or large patient categories were 16, 20 and 24 per cent respectively with likely errors within +/-5 per cent. Magnification factors were also calculated from the radiographic image of a 100 mm long rod which had been attached to the patien's thigh. The overall accuracy with this method was comparable to the techniques described above and had the advantage that every radiograph featured its own scale, a particularly important feature for preoperative films which have no implant for calibration purposes. As a result of such simple calibration procedures, it was possible to identify the overall magnification variations and specify particular magnification factors within +/-21/2 per cent (72'' films) or +/-5 per cent (40'' films).

Arthroplasty↗