The effect of rotatory subluxation of the scaphoid on radio-scaphoid contact

The effect of progressive rotatory subluxation of the scaphoid on radio-scaphoid contact area was examined in a cadaveric model. Five degrees of subluxation reduced the contact area of the proximal pole by 44%, with a shift to the dorsal lip of the radius. At 20 degrees of subluxation the contact area was reduced by 77%, with a shift radially to the dorsal lip of the radial styloid. These findings explain the progression of radio-scaphoid arthritis from the radial styloid to the remainder of the fossa and reemphasize the importance of operative reduction of a scapho-lunate disassociation in the prevention of degenerative arthritis.

The effect of a simulated scaphoid malunion on wrist motion

A scaphoid malunion results when a scaphoid fracture heals in a flexed position or when a scaphoid nonunion with carpal collapse is grafted without correction of the angular deformity. The effects of scaphoid malunion on wrist motion were simulated in a cadaveric study. It was found that the loss of wrist extension is proportional to the angular deformity. Loss of radiocarpal extension occurred at 15 degrees of angulation and loss of midcarpal extension occurred at 30 degrees of angulation.

Chronic tenosynovitis caused by Actinobacillus actinomycetemcomitans

This is the first report of a patient with a history of painless chronic flexor tenosynovitis caused by Actinobacillus actinomycetemcomitans. The slow growth of the organism on culture makes early identification difficult. Flexor tenosynovitis along with proper antibiotic treatment resulted in complete resolution in this patient.

Systems for producing precise movements of a joint over a wide range of speeds and displacements for tests of a static-position sense

This report describes 3 types of apparatus that were used to produce precise movements of a joint over a wide range of speeds and angles. The designs feature an ability for ultra slow rotation of the joint (fractions of a degree per min) with a minimum of extraneous cues. Two designs use servo-controlled DC motors configured as velocity servos and a third design uses a galvanometer motor configured as a position servo. Originally designed for use with humans in studies of proprioception with the ankle and two joints of the index finger (the metacarpophalangeal joint and proximal interphalangeal joint), the apparatuses should be useful in a variety of applications where precise control of velocity and position is needed.

Stenosing tenosynovitis in Dupuytren's contracture

Patients with symptoms of stenosing tenosynovitis and clinical evidence of overlying Dupuytren's contracture were treated with localized total fasciectomy through multiple Y-V plasties and the excision of the A1 pulley of the affected digit. At operation the stenosing tenosynovitis could be separated into two categories--patients with external compression from contracting vertical septa or patients in whom the tendon constriction appeared unrelated to the overlying fascial disease.

Effects of water-soluble components of cheese on experimental caries in humans

The effect of water-soluble components of extra-old Cheddar cheese on experimental caries was tested by means of the seven-day intraoral cariogenicity test (ICT). Two bovine enamel blocks were placed in each buccal flange of the dental appliances of five volunteers. One side of each appliance (experimental) was dipped in a 25% water extract of the cheese for five min, while the other side (control) was dipped in de-ionized water. Immediately thereafter, the appliance was returned to the subject's mouth, and two 60-second rinses with 10% sucrose were performed. These procedures were repeated six times per day. The cheese-extract dippings reduced the cariogenicity of the sucrose by an average of 55.7% (p less than 0.01), as assessed by enamel microhardness. Neither the mean resting pH nor the mean minimum pH in response to sucrose was significantly different between the experimental and control sides. The concentration of calcium was significantly higher in plaque from the experimental side (32.44 micrograms/mg) as compared with the control side (19.36 micrograms/mg, p less than 0.01). The concentration of plaque phosphorus was higher on the experimental side (12.90 micrograms/mg) than on the control side (9.61 micrograms/mg); however, the difference was not statistically significant. These results show that cheese has one or more water-soluble components which reduce experimental caries in human subjects.

Proprioception with the proximal interphalangeal joint of the index finger. Evidence for a movement sense without a static-position sense

Proprioceptive ability with the proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints of the index finger in human subjects was examined using a method that could assess static-position sense independently of movement sense (Clark et al., 1985). The similarity in location and function of these joints would suggest similar proprioceptive mechanisms, but proprioceptive ability was found to be quite different for the two joints. The method of distinguishing a static-position sense from a movement sense was based on whether a subject's ability to detect a small change in joint position was impaired when the rate of rotation was progressively reduced. An awareness of static-position should not depend on the rate at which a joint is placed into position. However, if subjects use movement signals to detect changes in joint position, slowing the rate of displacement should reduce the intensity of these signals and make the displacements more difficult to detect. This method indicated a static-position sense with the MCP joint but only a movement sense with the PIP joint. It was confirmed that sensory input from regions of skin not stretched or deformed by rotation of the joint can influence proprioceptive sensibility with the fingers. Anaesthesia of the tip of the index finger or of the thumb blunted subject's perceptions of movement of the PIP joint of the index finger. However, anaesthesia of the PIP joint itself had no observable effect on the ability to sense movement of the joint.

Matched distal ulnar resection

Painful disorders of the distal radioulnar joint severely limit the work capability of the hand. Until recently, the standard treatment for this problem has been transverse resection of the distal ulna, as originally proposed by Darrach. A technique for a "matched" resection arthroplasty of the distal ulna, leaving the ulnar shaft--styloid axis along with the triangular fibrocartilage complex and the distal ulnar ligamentous attachments intact, has been used since 1967. This procedure resects the distal ulna in a long, smooth, convex curve, matching the opposing surface of the concave radial metaphysis in three dimensions. Forty-four wrists were followed for an average of 6.5 years and showed that the procedure is reliable and relieves pain while retaining a more normal ulnocarpal, radioulnar, and radiocarpal alignment, with painless pronation averaging 80.5 degrees and supination of 88.5 degrees.

Accumulation of nifedipine after multiple doses

The single and multiple dose pharmacokinetics of oral nifedipine capsules, 10 mg, have been examined in five patients with peripheral vasospasm. After a single dose, nifedipine was rapidly absorbed in three and slowly absorbed in two patients. Mean bioavailability parameters included a tmax of 2.9 h, a Cmax of 33.3 ng ml-1 and a AUC0-8 h of 113.3 ng h ml-1. After multiple dosing with either 10 or 20 mg every 8 h for 10 days the mean tmax at steady state was 2.1 h while the mean dose-corrected (to 10 mg) Cmax and AUC0-8 h were 51.9 ng ml-1 and 146.9 ng h ml-1, respectively. The mean elimination rate constant was 0.173 h-1 after both single and multiple doses. The mean extent of accumulation of nifedipine, defined as the ratio of AUC0-8 h (steady state)/AUC0-8 h (single dose), was 1.3; we concluded that nifedipine accumulates in the body when it is administered every 8 h. This should be taken into account when predicting steady state serum concentrations and haemodynamic effects of nifedipine from single dose kinetic data.

Role of intramuscular receptors in the awareness of limb position

We studied proprioception with the ankle joint and the metacarpophalangeal (MCP) joint of the index finger of humans by use of a method that could distinguish a position sense from a movement sense. The test measured how subjects' ability to detect a fixed displacement of a joint varied with the rate of joint rotation. A position sense should not depend on the speed of joint placement; therefore slow rates of movement should not degrade subjects' ability to sense joint displacements. However, in the absence of a position sense, subjects would presumably rely on movement signals that do depend on the rate of rotation, and their ability to detect displacements should decrease when rate decreases. Subjects could sense small displacements of the ankle (+/- 3.5 degrees) and the MCP joint (+/- 2.5 degrees lateral excursions) with no decrement in performance at speeds as low as 0.25 degrees/min for the ankle and 0.5 degrees/min for the MCP joint (the slowest tested thus far). The findings confirm the existence of a position sense with these joints. Block of the ulnar nerve at the wrist, which paralyzes the interosseous muscles that adduct and abduct the MCP joint but presumably leaves skin and joint mechanisms unaffected, substantially impaired subjects' ability to detect the lateral excursions at slow speeds. Performance fell sharply at speeds less than 128 degrees/min and leveled off at approximately 20% detections at speeds less than 4 degrees/min. Increasing displacement to +/- 7 degrees did not improve performance. Block of the common peroneal nerve at the knee, which paralyzes the ankle dorsiflexor muscles, substantially impaired subjects' ability to detect the +/- 3.5 degrees displacements at slow speeds when the foot was positioned to slacken the plantarflexion muscles (which were not affected by the block). Performance fell sharply at speeds less than 256 degrees/min and approached zero at speeds less than 16 degrees/min. However, positioning the foot to stretch the plantarflexor muscles restored subjects' performance to near normal. Local anesthetic injected into the MCP joint space produced no observable effect on the ability to detect either slow or fast excursions. The joint anesthesia went unnoticed by the subject. We conclude that independent and separable senses exist for limb position and limb movement and that normal position sense requires sensory inputs from the muscles.

Rheumatoid wrist reconstruction utilizing a fibrous nonunion and radiocarpal arthrodesis

Rheumatoid arthritic involvement of the wrist severely limits the functional status of the upper extremity. Total wrist arthrodesis, while providing pain relief and reestablishing support, compromises the functional capacity of the hand because of lack of wrist motion. Wrist arthroplasties allow motion, but have not found wide acceptance because of instability and the recurrence of deformity. A technique for establishing an intentional fibrous nonunion between the carpus and the radius was devised 17 years ago. This fibrous hinge gives wrist stability with or without radiocarpal wrist arthrodesis while allowing painless motion at the fibrous radiocarpal hinge and at the less severely involved midcarpal joint. Twenty-three patients have been followed for more than 7 years. All patients whose wrists achieved nonunion had no pain. Twelve of the 19 wrists in which radiocarpal arthrodesis occurred had no pain, and seven had mild pain that did not limit use.

The management of nonunions following high tibial osteotomies

Nonunion is an uncommon complication of high tibial osteotomy. Reported techniques of treating such a complication include resection of the pseudarthrosis and cast immobilization with risk of joint stiffness and loss of alignment. The special AO/ASIF threaded external fixator with double clamps was used to treat three patients with nonunions following high tibial osteotomy for medial compartment osteoarthritis. The pseudarthrosis was not resected in any instance. All were allowed full unrestricted joint motion postoperation. Rapid healing of the osteotomy ensued. The external fixator achieved excellent stability and rapid union while maintaining joint motion.

Infrapatellar tendon ruptures

This is a retrospective study of 23 infrapatellar tendon ruptures in 22 patients seen at Henry Ford Hospital from 1969 to 1980. Two of the patients had a systemic disease known to predispose to tendon ruptures, while the remainder of the tendon ruptures occurred in otherwise normal individuals as the result of either repetitive or isolated trauma.

Post-traumatic posterior radial head subluxation. Two case reports

Two women, 33 and 55 years of age, with post-traumatic posterior radial head dislocation were treated by open reduction. Normal apposition of the radius to the capitellum was achieved. Although excellent range of motion was restored in both patients, the possibility of post-traumatic arthritis must be determined by long-term follow-up observations.

Effect on caries of self-application of a zirconium silicate paste containing 9% stannous fluoride

A 2-year clinical trial was conducted using an adolescent population from a low-fluoride area to evaluate the anticaries effect of self-applications of zirconium silicate paste containing 9% stannous fluoride. tthree study groups totaling 464 children, with an initial average of 12.8 years, completed the study. The control group brushed with a non-fluoride zirconium silicate paste (tzircate Prophylaxis Paste) once each year: the first experimental group brushed with zirconium silicate paste containing 9% stannous fluoride (Zircate Treatment Paste) once each year; and the second experimental group brushed every 6 months with Zircate Treatment Paste. After 2 year, the DMFT and DMFS increments were virtually identical for the control group and the group that received one application of fluoride paste per year. The group that received two applications of fluoride paste per year had a DMTF increment that was about 24% less than that of the control group; however, the DMFS increment was only 5% less. These differences were not statistically significant at the P=.05 level.

Amelogenins. Purification and partial characterization of proteins from developing bovine dental enamel

1. Procedures are described for the purification of amelogenin electrophoretic components and their analysis for homogeneity by polyacrylamide-gel electrophoresis at both acidic and alkaline pH values. 2. Most of these components belonged to two main groups, termed the J group and the C group after their major electrophoretic components. Sodium dodecyl sulphate-polyacrylamide-gel electrophoresis indicated that, within each group, proteins were of similar size, but the C-group proteins were larger than those of the J group. 3. By sedimentation-equilibrium ultracentrifugation and amino acid analysis, the four J-group components were found to be very small proteins (mol. wt. 5500-3000) and, except for one, similar in amino acid composition. The components of the C group were found to be proteins of moderate size (mol. wt. 16800-16100) with very similar amino acid compositions. A third minor amelogenin group of intermediate size was also found, but not further analysed. Details of the results of the ultracentrifuge studies are given in a supplementary paper that has been deposited as Supplementary Publication SUP 50014 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973) 131, 5. 4. Two of the J-group components were similar to amelogenins isolated by other workers. 5. All amelogenins analysed were rich in proline, glutamic acid, histidine and methionine, and contained no half-cystine. Their amino acid compositions, combined with their molecular weights, serve to distinguish the amelogenins from both collagens and keratins.