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Biomedical subjects

G D Pettit

Publications and source records attributed to G D Pettit.

At least 19 recordsLinked to original sources
PubMed1992

History of external skeletal fixation.

The concept of external skeletal fixation was introduced by Malgaigne in 1840, with a spike driven into the human tibia that was held by a strap encircling the limb. The first readily available external fixator, the Parkhill clamp, appeared in 1897. By the 1920s, a number of adaptations of pins or screws inserted into bone fragments for external control of reduction and fixation had been published. Important developments in that era were triangular half-pin units and anchoring bone pins in both cortices. The Stader splint, which was the first half-pin splint to provide reduction as well as fixation, was used by surgeons in the U.S. Navy during World War II. The Kirschner-Ehmer splint, a veterinary modification of the Anderson splint for humans, was introduced in 1947. Popularity of external skeletal fixation declined in the 1950s because of poor results that may have been caused by errors of application. Improvements in fixator configurations and the skill and judgment of surgeons led to the current acceptance of the method.

Animals↗
PubMed1989

Stress shielding reduced by a silicon plate-bone interface. A canine experiment.

Effects of modifying the plate-bone interface with Silastic were tested. The experimental plate, i.e., a conventional plate with a Silastic backing was compared with the standard plate. In vitro four-point bending tests showed similar strain per load behavior in the experimental and standard plate models. In vitro plate-bone contact was greater and interface pressure was lower for the experimental as compared with the standard plate. An in vivo implant study was conducted where the plates were tested on intact canine femurs. At 27 weeks postimplantation, there was less porosity and remodeling in the haversian envelope of bone plated with a Silastic interface.

Animals↗
PubMed1984

The effect of bilateral medial meniscectomy on articular cartilage of the hip joint.

Bilateral medial meniscectomy of the knee joint was undertaken in 4 mature greyhounds. Four greyhounds of similar age served as nonsurgical controls. Six months after meniscectomy, all animals were sacrificed and femoral head articular cartilage (FHC) examined for collagen, uronic acid, galactosamine, glucosamine and hyaluronic acid (HA) content. The sequential extractability of proteoglycans (PG) with non-dissociative (0.5 M GuHCl) and dissociative (0.4 M GuHCl) solvents was also investigated. The levels of collagen, uronic acid, galactosamine and glucosamine of the FHC of the meniscectomized group remained normal relative to FHC taken from the control greyhounds but the level of HA was significantly depressed (p less than 0.05). The amount of PG extracted by 0.5 M GuHCl from the FHC of the meniscectomized group was 2.5 X that extracted from control cartilage. In addition, subsequent extraction of the residues with 4.0 M GuHCl only released half the amounts of PG extracted from control FHC under the same conditions.

Animals↗
PubMed1983

Effect of postoperative immobilisation on the regrowth of the knee joint semilunar cartilage: an experimental study.

Bilateral total medial meniscectomy was undertaken in the knee joints of 12 adult greyhounds. One-half of the animals had one meniscectomised joint immobilised by an external fixation system for 5 weeks following meniscectomy. All animals were sacrificed 6 months after surgery. The menisci (regrown and normal) were examined for collagen content and analysed histochemically to assess collagen assembly and glycosaminoglycan (GAG) distribution. Although the collagen content of regrown tissues were not statistically different from normal medial or lateral menisci, the fibre development and GAGs were abnormal. It is concluded that movement following meniscectomy is likely beneficial to the matrix formation in the regenerating tissue, but this together with weight bearing may have a detrimental effect on articular cartilage of the medial joint compartment.

Animals↗
PubMed1983

The effects of postoperative joint immobilization on articular cartilage degeneration following meniscectomy.

Bilateral medial meniscectomy was performed in 12 mature greyhounds. One knee joint of half the group was immobilized by a Kirschner splint for a period of 5 weeks immediately following meniscectomy, after which the device was removed and the animals were allowed free movement for a further 21 weeks before sacrifice. Three greyhounds served as controls. While the collagen levels of articular cartilage from the femoral condyles and tibial plateaus of meniscectomized animals were the same as that of controls, differences were found for proteoglycan (PG) content and extractability using nondissociative conditions (0.5 M guanidinium hydrochloride (GuHCl) but not dissociative conditions (4.0 M GuHCl). With nondissociative conditions, twice as much PG was extracted from medial femoral condyle of meniscectomized animals encouraged to bear weight on joints immediately after surgery compared to that from controls or animals in whom joints were immobilized after surgery. Proteoglycans from medial tibial plateau cartilage of the free contralateral joints of the immobilized group were more readily extracted using 0.5 M GuHCl and also showed a statistically significant depression of uronic acid levels relative to both controls and tissues of other surfaces. The data suggest that postoperative management of meniscectomy in the human may be more important than has hitherto been recognized.

Animals↗
PubMedDate not supplied

Tissue reaction to suture material in the feline linea alba. A retrospective, prospective, and histologic study.

Swelling and inflammation along the incision line were observed after elective ovariohysterectomy in 22 of 66 cats in a retrospective study. In a prospective study of 99 feline abdominal incisions closed with surgical gut, polyglactin 910, or polydioxanone, with and without subcutaneous closure, the least inflammation occurred when the linea alba was sutured with polyglactin 910 and the subcutaneous tissues were not sutured. Histologically, reactions in the linea alba of 12 other cats progressed from purulent to fibromononuclear to fibrous within 14 days after closure with gut, polyglactin 910, and polydioxanone. Microscopic evidence of seroma formation in 9 of 12 animals in which the subcutaneous tissue was not sutured suggested that surgical closure of subcutaneous dead space was indicated. The inflammatory reaction did not appear to be related to any one suture material as reactions were seen with all of them.

Abdominal Muscles↗