Use of an on-line, precolumn photochemical reactor in high-performance liquid chromatography of naphthodianthrones in Hypericum perforatum preparations.

A method has been developed for the determination of naphthodianthrones in Hypericum perforatum L. extracts and phytopharmaceutical preparations by high-performance liquid chromatography combined with on-line, precolumn photochemical conversion followed by photodiode-array detection. The chromatographic separation was performed on a C18 column under isocratic reversed-phase conditions.

Morse-type tapers: factors that may influence taper strength during total hip arthroplasty.

We studied the effect of varying impaction force, repeated impactions, and fluid contamination on the disassembly strength of Morse-type tapers in 4 commercially available, modular femoral total hip components. The effect of varying techniques of taper assembly on the distraction force was studied. Our results show a reproducible and linear relationship between the taper impaction force and the disassembly force.

Periprosthetic fractures of the femur.

Periprosthetic fractures of the femur represent a heterogeneous and challenging problem for the orthopedic surgeon. The incidence of these fractures is dramatically increasing, as there are more and more patients with aging total joint replacements. The fractures may occur as the result of a traumatic event, but more often are the result of minor trauma spontaneous fracture, and they are frequently associated with preexisting, sometimes neglected, problems with the associated joint replacement.

Femoral neck fractures.

Femoral neck fractures in the geriatric patient continue to represent a therapeutic challenge. Despite advances in surgical techniques and medical care, the risk of nonunion and osteonecrosis after fixation have not changed appreciably in the last 50 years. Considerable debate continues to occur with respect to the relative merits of internal fixation versus arthroplasty.

In vitro stability of cemented and cementless femoral stems with compaction.

Rigidity of initial fixation is a key factor contributing to the longevity of cemented and cementless femoral components in total hip arthroplasty. The objective of this study was to measure the initial stability of primary cemented and cementless femoral components under load when 15 pairs of cadaveric femurs were prepared by outward compaction of femoral cancellous bone in situ or by conventional extraction broaching. Three-dimensional micromotion was measured at proximal and distal locations on the femoral components using a device with spherical targets and linear variable differential transformers.

Antegrade intramedullary nailing of the humerus complicated by heterotopic ossification of the deltoid: a case report.

A case of antegrade nailing of the humeral shaft in a polytrauma patient was complicated by heterotopic ossification of the lateral deltoid muscle and severe loss of shoulder motion. The patient did not respond to physiotherapy alone and was successfully managed by excision of the heterotopic bone and adjunctive radiation therapy.

Pathophysiology of infections after internal fixation of fractures.

Infection complicating internal fixation of fractures is a serious complication that is difficult to treat. Whenever metallic devices are implanted in vivo, successful biointegration requires that host cells colonize the highly reactive implant surface. Bacteria such as staphylococci can also become adherent to metallic or polymeric implants and will compete with host cells for colonization of the implant surface.

A prospective, randomized study of intramedullary nails inserted with and without reaming for the treatment of open and closed fractures of the tibial shaft.

Objectives: To determine if there are differences in healing, complications, or number of procedures required to obtain union among open and closed tibia fractures treated with intramedullary (IM) nails inserted with and without reaming.

Design: Prospective, surgeon-randomized comparative study.

Setting: Level One trauma center.

General synthetic entry to linearly-fused dihydrobenzocyclobutene-1,2-diones and benzocyclobutene-1,2-diones via annulation of 1,2-bis(methylene)carbocycles with 3-chloro-3-cyclobutene-1,2-dione.

The tandem Diels-Alder/dehydrochlorination reaction of semisquaric chloride (1) with the 1,2-bis(methylene)cycloalkanes 2a-c and 1,2-bis(methylene)-4-cyclohexene (9) affords the linearly-fused cycloalkanodihydrobenzocyclobutene-1,2-diones 3a-c and 3,4,7,8-tetrahydrocyclobuta[b]-naphthalene-1,2-dione (10), respectively. On treatment with MnO2, 3a-c are dehydrogenated to the respective carbocycle-fused benzocyclobutene-1,2-diones 4a-c in good yields. 3a and 3b react with bromine to give the addition products 5a,b, which, on treatment with silver trifluoroacetate, afford the benzocyclobutene-1,2-diones 4a,b.

Improving the detection of acetabular osteolysis using oblique radiographs.

Visualisation of periacetabular osteolysis by standard anteroposterior (AP) radiographs underestimates the extent of bone loss around a metal-backed acetabular component. We have assessed the effectiveness of standard radiological views in depicting periacetabular osteolysis, and recommend additional projections which make these lesions more visible. This was accomplished using a computerised simulation of radiological views and a radiological analysis of simulated defects placed at regular intervals around the perimeter of a cadaver acetabulum.

Blood conservation in hip trauma.

Patients with hip or pelvic fractures experience significant blood loss as a result of the fracture and from the surgery that subsequently is performed. The emergent and unplanned nature of fracture surgery precludes the use of preoperative blood donation and the optimization of chronic medical problems. Blood transfusion frequently is required to maintain adequate tissue O2 delivery in these injured patients.

Periprosthetic metastatic carcinoma. Pitfalls in the management of two cases initially diagnosed as osteolysis.

Periprosthetic osteolysis is a well-described phenomenon associated with total hip arthroplasty. Two cases are presented in which apparently healthy patients developed lytic lesions adjacent to cementless hip implants. Despite atypical features, the lesions were initially attributed to wear debris-induced osteolysis, and it was discovered during revision surgery that metastatic tumor was present.

Nonreamed interlocked intramedullary tibial nailing. One community's experience.

Forty-nine acute displaced tibial fractures (31 closed, 18 open: 5 Grade I, 7 Grade II, 4 Grade IIIA, and 2 Grade IIIB) were treated in 1 community with a standard operative protocol using a distractor without a fracture table, and an unreamed interlocked tibial nail. Forty-six fractures healed (94%). Complications included 3 nonunions (6%), 2 deep infections (4%), 9 delayed unions (18%), 4 angular malunions (8%), 2 rotatory malunions (4%), and 12 interlocking screws bent or broke (24%).

Fractures of the proximal part of the femur.

The orthopaedic surgeon has a multitude of internal fixation devices and techniques available for use in the treatment of subtrochanteric fractures of the proximal femur. The successful use of second-generation locking nails is technically demanding. Close attention to positioning of the patient, reduction of the fracture, placement of the guide-wire, and insertion of the nail and of the proximal and distal locking screws is mandatory.

Pelvic osteotomy for bladder exstrophy.

Twenty-five patients with bladder exstrophy underwent pelvic osteotomy at or before initial bladder closure and anterior abdominal repair. Ten patients underwent bilateral iliac osteotomies before 1977. An alternative procedure consisting of bilateral superior pubic ramotomies has been used in 15 patients since 1977.

Assessment of bone viability in patients with osteomyelitis: preliminary clinical experience with laser Doppler flowmetry.

The intraoperative determination of bone viability is of fundamental importance in the surgical management of osteomyelitis. Recurrent infection will result from inadequate debridement, whereas reconstructive problems will be magnified by overzealous resections. The purpose of this article is to report the use of laser Doppler flowmetry (LDF) as a surgical adjunct allowing quantitative determination of bone viability in patients with osteomyelitis.

Muscle injury induced beneath and distal to a pneumatic tourniquet: a quantitative animal study of effects of tourniquet pressure and duration.

Previous recommendations regarding the "safe" period of tourniquet hemostasis were based largely on studies of ischemia distal to the tourniquet. This study quantitatively analyzed skeletal muscle injury induced beneath and distal to a pneumatic tourniquet applied to the hindlimbs of rabbits for 1, 2, or 4 hours with a cuff inflation pressure of 125, 200, or 350 mm Hg. Technetium Tc 99m pyrophosphate incorporation after systemic injection (Tc 99 uptake) and correlative histology were used to evaluate tissue damage 2 days after tourniquet application.