PubMed Health⌕ Search

Biomedical subjects

B J Gainor

Publications and source records attributed to B J Gainor.

At least 19 recordsLinked to original sources
PubMed2002

The use of detergent irrigation for musculoskeletal wounds.

The primary purpose of irrigation is to remove bacterial contaminants from the wound. Surfactants do that by disrupting the bonds of the organism to the surface. The use of this wound care strategy was studied in a series of investigations spanning several years. In vitro experiments revealed that surfactant irrigation was superior to saline or antibiotic solutions for removal of adherent bacteria from metallic surfaces, from bone, and from bovine muscle. An in vivo model of the complex orthopedic wound was developed. The superiority of surfactant irrigation over saline or antibiotic solution was demonstrated in animal wounds containing metal, bone injury, and soft tissue damage. Specificity of different surfactant irrigations for various bacterial species was demonstrated. A sequential surfactant irrigation protocol was developed and shown effective in the polymicrobial wound with established infection.

Animals↗
PubMed2001

Synergy between Staphylococcus aureus and Pseudomonas aeruginosa in a rat model of complex orthopaedic wounds.

BACKGROUND: We observed an interaction in animals inoculated concomitantly with Staphylococcus aureus and Pseudomonas aeruginosa during a study of the efficacy of surfactants for disinfection of orthopaedic wounds. This led us to investigate whether synergy could be demonstrated between Staphylococcus aureus and Pseudomonas aeruginosa in a rat model of complex orthopaedic wounds. METHODS: A wire was implanted into the spinous process of a lumbar vertebra of Sprague-Dawley rats through a dorsal incision. Animals were divided into two groups: group one was inoculated with either Staphylococcus aureus or Pseudomonas aeruginosa, and group two received a polymicrobial inoculation with both test organisms in varying concentrations. After inoculation, the wounds were irrigated and closed. On postoperative day 14, all animals were killed and specimens from the wounds were cultured. The number of colony-forming units (CFU) of Staphylococcus aureus or Pseudomonas aeruginosa needed to cause infection in 50% of the animals (ID50) was determined with use of the Reed-Muench method. The infection rate associated with each inoculum combination was calculated, and the two groups were compared. RESULTS: The ID50 was 2.8 x 10(4) CFU for Staphylococcus aureus and 4.8 x 10(5) CFU for Pseudomonas aeruginosa. The combination of 10(3) CFU of Staphylococcus aureus with low concentrations (10(2), 10(3), or 10(4) CFU) of Pseudomonas aeruginosa yielded infection rates that were higher than those found with either organism alone at the same concentrations. The combination of 10(3) CFU of Staphylococcus aureus and 10(3) CFU of Pseudomonas aeruginosa yielded a 75% infection rate, which was significantly higher (p = 0.004) than that associated with 10(3) CFU of either organism alone. As the Pseudomonas aeruginosa concentration was increased (to 10(5), 10(6), and 10(7) CFU), this trend reversed, and the infection rate decreased to 33% (p = 0.004). Low concentrations of Pseudomonas aeruginosa (0 to 10(5) CFU) combined with 10(6) CFU of Staphylococcus aureus yielded infection rates ranging from 83% to 100%. At the higher concentrations of Pseudomonas aeruginosa (10(6) and 10(7) CFU), however, the infection rate again decreased, to 33% (p = 0.005). Only Staphylococcus aureus was isolated from the cultures of the specimens from the animals that had received a polymicrobial inoculum. CONCLUSIONS: Synergy between Staphylococcus aureus and Pseudomonas aeruginosa was demonstrated when low levels of each organism were present in the wound. As the Pseudomonas aeruginosa concentration was increased, the infection rates fell well below what would be anticipated, suggesting that low concentrations of Pseudomonas aeruginosa enhance the ability of Staphylococcus aureus to cause infection in this orthopaedic wound model. At the same time, the presence of Staphylococcus aureus in the ratios tested decreased the rate of infection by Pseudomonas aeruginosa. CLINICAL RELEVANCE: Staphylococcus aureus is a pathogen commonly seen in orthopaedic patients. The pathogenicity of Staphylococcus aureus was shown to be increased in the presence of anaerobic bacteria. This study is the first one that we are aware of that demonstrated synergy between Staphylococcus aureus and Pseudomonas aeruginosa, at low concentrations, in a wound model while at the same time showing that Staphylococcus aureus lowers the rate of Pseudomonas aeruginosa infection.

Animals↗
PubMed2000

Extensor tendon rupture secondary to the AO/ASIF titanium distal radius plate without associated plate failure: a case report.

Complications with open reduction and internal fixation of distal radius fractures have led to the development of the AO/titanium Pi-plate. This was designed to be a low-profile plate to decrease its intrusion into surrounding soft tissues. Recent case reports are revealing an association of tendon ruptures with failures of this plate. This case report demonstrates extensor tendon rupture without plate failure or prominent screw heads.

Adult↗
PubMed1999

Sequential irrigation with common detergents: a promising new method for decontaminating orthopedic wounds.

This investigation sought to determine the capacity of irrigation solutions in decontaminating orthopedic wounds challenged with a polymicrobial inoculum. Rats were divided into two groups, a control group and a treatment group. After creation of a dorsolumbar incision and placement of a wire through the spinous process, rats were inoculated with Staphylococcus aureus and Pseudomonas aeruginosa. Wounds were irrigated with control or treated solutions. At 2 weeks, cultures were obtained. There were statistically significant differences between groups regarding total number of culture positive sites (P < 0.001), culture-positive animals (P = 0.02), and quantitative cultures (P < 0.02). Sequential irrigation with surfactants lowers bacteria counts recovered from polymicrobial wounds.

Analysis of Variance↗
PubMed1998

Benzalkonium chloride. A potential disinfecting irrigation solution for orthopaedic wounds.

The efficacy of benzalkonium chloride was evaluated as an irrigating solution for the eradication of Staphylococcus aureus from a contaminated orthopaedic wound. Thirty Sprague Dawley rats were randomized into two groups. A stainless steel wire was placed in a lumbar spinous process, and the wound was inoculated with 10(7) or 10(6) colony forming units of Staphylococcus aureus. The wound was irrigated with 1 L of normal saline or 0.1% benzalkonium chloride solution. The animals were sacrificed, and cultures were obtained. Rats inoculated with 10(7) colony forming units of Staphylococcus aureus and irrigated with benzalkonium chloride had a significant decrease in the total number of positive cultures, deep wound cultures, and stainless steel wire cultures. Rats inoculated with 10(6) colony forming units of Staphylococcus aureus and irrigated with benzalkonium chloride also had a significant decrease in the total number of positive cultures, deep wound cultures, and stainless steel wire cultures. In a parallel noninoculation study, histologic evaluation of tissues did not show toxicity in the rats irrigated with benzalkonium chloride. This study shows that benzalkonium chloride is more effective than normal saline as an irrigating agent for eradicating Staphylococcus aureus from a contaminated orthopaedic wound.

Animals↗
PubMed1996

Disinfecting agents for removing adherent bacteria from orthopaedic hardware.

This investigation seeks to determine whether surfactants or detergents can be used to clean and disinfect orthopaedic wounds with implanted hardware. Thus, a stepwise investigation of biocompatible surfactants and detergents was performed to identify an irrigation agent for disinfecting orthopaedic wounds. Bacterial adhesions assays, irrigation studies, and bactericidal assays determined that benzalkonium chloride showed the greatest efficacy. Testing involved stainless steel screws colonized with a preformed biofilm of Staphylococcus epidermidis, Staphylococcus aureus, or Pseudomonas aeruginosa, which were immersed in benzalkonium chloride solutions for various time intervals under static conditions. After 10 minutes, benzalkonium chloride achieved a minimum 4 log kill (10,000-fold) for all 3 strains of bacteria. Additional studies demonstrated that the high mechanical energy of jet irrigation improved the disinfecting properties of this agent. With jet lavage, both 1:1000 and 1:5000 concentrations of benzalkonium chloride achieved a minimum 2 log kill (100-fold) for all 3 bacteria. The results or this study suggest that at tissue compatible concentrations, benzalkonium chloride has significant disinfection properties for in vitro colonized orthopaedic devices, and these properties may be enhanced via jet lavage.

Anti-Infective Agents, Local↗
PubMed1995

Lasso stabilization of the distal ulna after tumor resection: a report of two cases.

Two patients with complicated giant cell tumors of the distal ulna were treated by resection of 7.5 and 5.5 cm of the ulna, respectively. The proximal ulnar stump was stabilized with a lasso tendon graft, which allowed the patients to return to presurgery activities. The technique described is a modification of a tendon loop reconstruction used by Bunnell.

Adult↗
PubMed1995

Healing rate of transverse osteotomies of the olecranon used in reconstruction of distal humerus fractures.

To determine the rate of healing of the osteotomy, we studied the cases of 10 patients who had transverse osteotomy of the olecranon for surgical exposure of a complex distal humerus fracture. The average age of the patients was 48 years, and the average follow-up was 24 months. Nine of the fractures were complex supracondylar/intercondylar fractures. All of the humerus fractures were treated with bone plates and screws, and nine of the osteotomies of the ulna were reconstructed with a large lag screw and tension band wire. Smooth pins and a tension band wire were used in 1 patient with osteoporotic bone. Union of the ulnar osteotomy occurred in 7 patients, and 3 of the patients had a nonunion. The average time of healing of the distal humerus fractures was 3.5 months, and the average time of healing of the ulnar osteotomies was 5.2 months. Six of the patients developed a gap at the osteotomy site by displacement or resorption of it, and two of these progressed to a nonunion. The patients whose ulnar osteotomy healed had an average extension lag of 33 degrees, and the average flexion at their elbows was 122 degrees. The patients who had a fibrous nonunion of the ulnar osteotomy had an average extension lag of 27 degrees at the elbow, and all 3 patients had full flexion of the elbow joint. Because of the nonunion rate of 30% in our patients, we no longer use a transverse osteotomy of the olecranon to expose distal humerus fractures at surgery.

Adolescent↗
PubMed1994

Orthofix external fixation of distal radius fractures: complications associated with screw size.

We did a retrospective analysis of 28 patients who were treated with the Orthofix external fixation system for complex fractures of the distal radius to study complications associated with screw size. The 14 patients in group 1 had a 4.5/3.5-mm tapered screw placed in the metacarpal bone; the 14 patients in group 2 had a 3.5/3.3-mm tapered screw placed in the metacarpal bone. Both groups had 4.5/3.5-mm tapered screws placed in the radius. Two patients in group 1 had metacarpal pin tract infections; no patients in group 2 had a distal pin tract infection. Two patients in group 1 had a fracture of the metacarpal; only one patient in group 2 had a fracture of the metacarpal. In both groups two patients had proximal pin tract infections at the radius screw fixation site. There was no screw breakage in either group. The unique design of the tapered Orthofix screw allows it to be removed almost painlessly in the clinic. At installation in the operating room, however, the surgeon must remember not to back the threaded pin out for fine adjustment of bony penetration. Any reverse excursion of the threaded shaft will loosen the tapered screw and cause early failure of the fixation. We no longer use the 4.5/3.5-mm screw when managing wrist fractures with the Orthofix external fixation system. It is now our policy to use the 3.5/3.3-mm screw for fixation of the Orthofix external frame to both the metacarpal bone and the radius.

Adolescent↗
PubMed1993

Modified exposure for pronator syndrome decompression: a preliminary experience.

Because hypertrophic and symptomatic scarring is not infrequent from a lazy S incision across the antecubital fossa, a new surgical approach to the pronator tunnel has been developed. Preliminary experience with this modified incision has proven to be encouraging in seven cases (five patients). The exposure is composed of two off-set linear incisions which allow visualization of the median nerve and brachial artery distal and proximal to the lacertus fibrosis. An intact bridge of skin at the antecubital fossa protects the medial cutaneous nerves of the arm and forearm from injury. The median nerve is exposed by splitting the pronator teres along its length, and fractional step cutting of the pronator aponeurosis relaxes the muscle. Postoperative scar management with a compressive wrap and elastomer insert is helpful for cosmetic healing of the incisions.

Adult↗
PubMed1992

Wrist arthrodesis by intramedullary rod fixation: a valuable technique.

Arthrodesis of the wrist with intramedullary rod fixation is a simple technique that provides the opportunity for performing concomitant procedures. Iliac bone graft usually is not required with this technique, as the intramedullary rod is a load-sharing construct that allows compression at the fusion site and facilitates union. Rod removal usually is optional, and the long intramedullary beam effect of the rod can function as an internal splint if fibrous or hypoplastic union occurs. Early mobilization is possible, sometimes with only minimal splinting. The results with use of this technique over a ten year period of time in ten wrists (nine patients) with endstage radiocarpal joint instability are reported.

Adult↗
PubMed1991

Tendon arthroplasty of the fifth carpometacarpal joint for treatment of posttraumatic arthritis.

Resectional arthroplasty with interposition of a rolled tendon spacer was used to treat posttraumatic arthritis of the fifth metacarpal-hamate joint in eight patients. The average follow-up was 5 years. All of the patients subjectively rated the functional capability and the cosmetic appearance of their hands as good or excellent. After operation, there was a net increase of 30% in the average grip strength of the study group. The motion preserved at the small finger carpometacarpal joint facilitated power function of the hand.

Adult↗
PubMed1990

Combined entrapment of the median and anterior interosseous nerves in a pediatric both-bone forearm fracture.

Unrecognized entrapment of the median nerve and its anterior interosseous branch in the midportion of the forearm occurred in a 12-year-old girl following reduction of a closed both-bone fracture. Following delayed diagnosis, treatment required secondary neurolysis and microscopic neurorrhaphy. Meticulous prereduction and postreduction neurovascular examination is recommended to prevent this unique complication.

Child↗
PubMed1990

Early clinical experience with Orthofix external fixation of complex distal radius fractures.

Twelve patients with complex fractures of the distal radius were treated with the Orthofix external fixation system (EBI Medical Systems, Fairfield, NJ). On follow up physical examination, the average wrist dorsiflexion was 46 degrees, and the average volar flexion was 55 degrees. The average grip strength in the involved hand was 38 lb force. The average final radial angle was 18 degrees, and the average residual radial height was 12 mm. Average volar tilt was 3 degrees. The complication rate was 42%. Very rigid axial stability is afforded by the fixator, but the large 3.5 mm tapered bone screw diameter precludes redrilling for screw adjustment. The apparatus needs frequent monitoring to reconfirm the security of the locking nuts and cam mechanisms, and the Orthofix system can be reused only four times.

Adolescent↗
PubMed1990

The pronator compression test revisited. A forgotten physical sign.

Pronator compression testing is a valuable clinical feature of median nerve entrapment diagnosis. Of 10 patients with this disorder, all developed paresthesias preoperatively in the hand after 30 seconds or less of manual compression of the median nerve at or near the pronator muscle. Eight patients had a positive Tinel's sign at the impingement site, but only one patient had a positive electromyographic result. More than 50% of the patients had undergone previous carpal tunnel release or were diagnosed at presentation with double crush syndrome. All patients had a good or excellent result from surgical decompression of the median nerve in the forearm, except for one workers' compensation case who had excellent postoperative strength testing but multiple residual complaints. Pronator compression testing is a helpful and dependable physical sign in the diagnosis of pronator syndrome.

Carpal Tunnel Syndrome↗
PubMed1989

Proximal coiling of the profundus tendon after laceration of the finger.

Three patients who had delayed primary repair of a severed flexor digitorum profundus in the finger were found to have proximal coiling of the tendon in the palm. These patients' hands had been inadequately immobilised during the interval between injury and surgery. The most likely pathomechanics of this unusual finding is secondary retraction and coling of the severed tendon from unrestrained muscle contraction after division of the tendon. Precautions should be taken when retrieving the tendon stump for tenorrhaphy.

Adolescent↗