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Biomedical subjects

P F Partington

Publications and source records attributed to P F Partington.

15 recordsLinked to original sources
PubMed2004

Pre-heating of components in cemented total hip arthroplasty.

Fatigue fractures which originate at stress-concentrating voids located at the implant-cement interface are a potential cause of septic loosening of cemented femoral components. Heating of the component to 44 degrees C is known to reduce the porosity of the cement-prosthesis interface. The temperature of the cement-bone interface was recorded intra-operatively as 32.3 degrees C. A simulated femoral model was devised to study the effect of heating of the component on the implant-cement interface. Heating of the implant and vacuum mixing have a synergistic effect on the porosity of the implant-cement interface, and heating also reverses the gradients of microhardness in the mantle. Heating of the implant also reduces porosity at the interface depending on the temperature. A minimum difference in temperature between the implant and the bone of 3 degrees C was required to produce this effect. The optimal difference was 7 degrees C, representing a balance between maximal reduction of porosity and an increased risk of thermal injury. Using contemporary cementing techniques, heating the implant to 40 degrees C is recommended to produce an optimum effect.

Arthroplasty, Replacement, Hip↗
PubMed2004

Premature wear and osteolysis in an HA-coated, uncemented total hip arthroplasty.

The ABG I cementless hip prosthesis has demonstrated unacceptably high rates of wear and osteolysis in our patients. We performed a retrospective study of 97 hips implanted between 1992 and 1998. Radiographic analysis revealed high rates of wear of the polyethylene liner with marked peri-acetabular osteolysis. Clinical examination indicated that many of these patients were initially asymptomatic. Wear-related problems have required ten hips to be revised and a furher 13 are awaiting revision. This gives a failure rate of 24% at a mean follow-up of 69 months. Contributing factors are likely to include poor wear characteristics of the polyethylene liners which were gamma irradiated in air, and increased wear debris caused by a poor fit of the polyethylene liner within the shell. We believe that all ABG I implants should be immediately reviewed and remain under careful, long-term follow-up.

Adult↗
PubMed2002

Extramedullary or intramedullary tibial alignment guides: a randomised, prospective trial of radiological alignment.

We undertook a prospective, randomised study of 135 total knee arthroplasties to determine the most accurate and reliable technique for alignment of the tibial prosthesis. Tibial resection was guided by either intramedullary or extramedullary alignment jigs. Of the 135 knees, standardised postoperative radiographs suitable for assessment were available in 100. Correct tibial alignment was found in 85% of the intramedullary group compared with 65% of the extramedullary group (p = 0.019). We conclude that intramedullary guides are superior to extramedullary instruments for alignment of the tibial prosthesis.

Adult↗
PubMed1999

Joint line restoration after revision total knee arthroplasty.

In 99 patients, 107 knee replacements were revised in two centers by two surgeons using a single revision total knee arthroplasty system. A retrospective radiographic review of joint line position before and after revision total knee arthroplasty was made, and compared with the joint line position before primary knee arthroplasty. Prospectively collected Knee Society Clinical Rating Scores were correlated with radiographic findings. The joint line position in unreplaced knee replacements averaged 16 mm, and the joint line position in knee replacements before revision surgery averaged 17 mm. The joint line was elevated by the revision total knee arthroplasty in 85 of 107 knees (79%). After the revision total knee replacement, the joint line elevation averaged 24 mm. The Knee Society Clinical Rating Score after revision surgery averaged 131 points. If the joint line position was elevated more than 8 mm, the Knee Society Clinical Rating Score averaged 125 points, if the joint line was elevated less than 8 mm, the score averaged 141 points. Joint line elevation after revision total knee replacement is a problem. Excessive elevation may result in worse clinical outcomes. Distal femoral augments should be used more often and with greater thicknesses. Standard implants used for revision surgery should have increased distal dimensions.

Aged↗
PubMed1977

Twenty-three years of experience with sphincterotomy and sphincteroplasty for stenosis of the sphincter of Oddi.

A 23 year experience with papillotomy, sphincterotomy and sphincteroplasty for stenosis of the sphincter of Oddi shows sphincteroplasty to be the best procedure, with 79% of the patients obtaining a good result. The procedure was done for a demonstrable organic change in the sphincter, often associated with acute cholecystitis in older patients, the postcholecystectomy syndrome in those in whom a long cystic stump had been left at the first operation or in patients with chronic recurring pancreatitis. The study included 138 private patients observed from two months to 22 years. There were four postoperative deaths, an operative mortality of 2.9%, as two patients had been operated upon twice. The poor results were associated with recurring attacks of pancreatitis not cured by the procedure or developing subsequent to it, probably being attributable to persistent obstruction of the terminal part of the pancreatic duct. The results suggest that sphincteroplasty, if performed on suitably selected patients, is a safe procedure which should give good results in more than 75% of the patients.

Adult↗
PubMedDate not supplied

Diagnostic injection around the shoulder: hit and miss? A cadaveric study of injection accuracy.

In a cadaver study the success of injections in the subacromial space and acromioclavicular joint was studied. Twenty-four shoulders were dissected after separate dye injection was performed with the patient in the supine position. Subacromial bursa injection was successful in 83% (20 shoulders), but in 15 shoulders other structures were also infiltrated, including seven injections in the rotator cuff. Acromioclavicular joint injection was successful in 67% (16 shoulders), but half involved other structures. The authors believe that misplaced injections may be diagnostically misleading and potentially harmful.

Acromioclavicular Joint↗