Ectrodactyly-ectodermal dysplasia-clefting syndrome.

Ectrodactyly-ectodermal dysplasia-clefting syndrome is a rare congenital anomaly that affects tissues of mesodermal and ectodermal origin. Musculoskeletal involvement frequently requires orthopedic intervention. The authors present a review of the literature pertaining to this rare syndrome as well as a case report of a female patient who exhibited the complete clinical triad. A description of the surgical management of her condition is also presented.

Two- to five-year follow-up of 100 total hip arthroplasties using DF-80 implants.

In an uncontrolled prospective study, 100 primary total hip arthroplasties (THAs) using the DF-80 implant were followed up for a minimum of 2 years with rigorous clinical and radiographic examinations to define the natural history of this prosthetic system. Three groups were identified: (I) hips requiring revision because of failure (n = 3); (II) "impending" failures with radiographic indices of loosening (n = 8); and (III) clinically and radiographically benign, stable implants (n = 89). The preoperative Harris hip score was similar for all groups. Postoperatively, the failure group demonstrated early progressive clinical and radiographic deterioration with surgical revision at an average of 33 months. Male sex, increased weight, and greater intraoperative hemorrhage correlated positively with failure. The impending-failure group developed limited radiolucencies in the later postoperative period. Calcar resorption was noted in 26% of the total population and heterotopic ossification in 46%. We conclude that this series of THAs using DF-80 implants included a subset of patients demonstrating early clinical failure and widespread aggressive bone-cement radiolucencies that required early surgical revision.

Suboptimal (thin) distal cement mantle thickness as a contributory factor in total hip arthroplasty femoral component failure. A retrospective radiographic analysis favoring distal stem centralization.

One hundred cemented total hip arthroplasties (THAs) were evaluated regarding the potential benefit of THA femoral component distal stem centralization, specifically regarding cement mantle thickness. Factors potentially predictive of femoral component mechanical loosening, both relating (22 factors) and not relating (41 factors) to cement, were analyzed on initial postoperative radiographs. Nine THAs with femoral component mechanical failure (group 1) were compared to (1) 88 non-failed THAs (group 2) and (2) 9 matched-paired, nonfailed THAs (group 3). Significant differences were evident regarding minimum and maximum cement mantle thickness in Gruen zone 5 and combined zones 5/6 (groups 1 vs 2 and groups 1 vs 3), with failed femoral components having thinner cement mantles. Discriminate analysis determined minimum cement mantle thickness in zone 5 to be the factor most predictive of femoral component failure. These data indicate that a suboptimal (thin) cement mantle at the medial diaphysis (Gruen zones 5 and 6) contributed to femoral component mechanical loosening in this THA series. This relationship may not pertain to femoral stems of different materials or cross-sectional characteristics. Many THA systems currently provide for a method of centralization of the femoral component distal stem as a mechanism to ensure an adequate circumferential distal cement mantle. Continued investigation into techniques directed toward centralization of the distal femoral stem is warranted by the findings of this study.

Steroid-related osteonecrosis of the knee. Two case reports and a literature review.

Steroid-related osteonecrosis of the knee has been only rarely reported, especially without concomitant hip involvement. Two such cases are documented with correlated roentgenographic and magnetic resonance imaging. A comprehensive review of the literature illustrates the diverse circumstances in which this rare condition may occur.

A light and scanning electron microscopic study of osteocyte activity in calcium-deficient rats.

The material herein is an extension of an earlier study of osteocyte lacunae in calcium-deficient rats, utilizing morphometric measurements in undecalcified bone sections and scanning electron microscopy. The results confirm our earlier finding that bone resorption resulting from a low-calcium diet is not accompanied by osteocytic resorption.

Gait laboratory analysis of a posterior cruciate-sparing total knee arthroplasty in stair ascent and descent.

Successful posterior cruciate ligament-sparing total knee arthroplasty functions in an equivalent fashion to a contralateral normal limb during the mechanical stresses of stair ascent and descent. Motion and force plate analysis reveal highly symmetric gait patterns. Sagittal angles are greater than previously reported for the total condylar prosthesis and are nearly equal to those recorded for the age-matched normal population.

Homologous oxypiperidines as inhibitors of protein synthesis in vitro and ex vivo.

The antioxidant nitroxyl-2 (2,2,6,6-tetramethyl-4-oxypiperidine-1-oxyl) is an active inhibitor of protein synthesis both in vitro (rabbit reticulocyte lysate cell-free translation system) and ex vivo (mouse liver). Demethylated derivatives of this agent demonstrate a significantly lower inhibitory activity. There is a strong positive correlation between quantitative parameters of toxicity, the ex vivo and in vitro inhibitory effects on translation, and the total number of methyl groups per drug molecule.

The in vitro screening of methylated 4-oxypiperidine compounds for inhibition of protein synthesis in a rabbit reticulocyte cell-free translation system.

A variety of methylated 4-oxypiperidine derivatives were tested for their ability to inhibit protein synthesis in vitro. A direct correlation was found between the extent of methylation of these compounds and their inhibitory activity in a rabbit reticulocyte lysate cell-free translation system.

Mechanisms of bone resorption in calcium-deficient rats.

A study of surface remodeling activity and osteocyte lacunar area was made in young and adult rats maintained on a low-calcium diet, to explore cellular mechanisms of bone resorption. The diet produced active remodeling of the endosteal part of the femoral cortex, with a decrease in the amount of bone present. Surface resorption, with numerous osteoclasts, was evident, but there was no evidence of osteocytic osteolysis in bone which, by tetracycline labeling, could be identified as existing at the commencement of the experimental period. Osteocyte lacunae in bone formed during the period of calcium deprivation were somewhat larger than lacunae in control animals, apparently because of interference with the formation or maturation of the perilacunar tissue.