Biomedical subjects

R R Richards

Publications and source records attributed to R R Richards.

At least 19 recordsLinked to original sources

PubMed1995

Grip strength testing using the BTE work simulator and the Jamar dynamometer: a comparative study. Baltimore Therapeutic Equipment.

This study compared the results obtained from testing grip strength using the hydraulic Jamar dynamometer and the BTE Work Simulator. The grip strength of 14 adults was assessed with the Jamar at 90 degrees elbow flexion, Jamar at 45 degrees elbow flexion, and the BTE using the manufacturers recommended position. Greater strength measurements were generated with the elbow at 90 degrees rather than 45 degrees on the Jamar. The Jamar measurements at 90 degrees of elbow flexion were not significantly different from the BTE work simulator values. Intraclass correlation coefficients between the Jamar at 90 degrees and the BTE work simulator values were excellent. This study demonstrated that the results obtained from the BTE work simulator and the Jamar dynamometer are comparable. These findings validate the use of the BTE work simulator for grip strength testing.

Adult↗

PubMed1995

A Madreporic-surfaced femoral component in a canine total hip arthroplasty model: bone remodelling response at 6 and 24 months.

OBJECTIVE: To evaluate the bone-remodelling response at 6 and 24 months after total hip arthroplasty around a two-thirds Madreporic-surfaced femoral component in a canine model. DESIGN: A research study in dogs. Statistical analysis was by multivariate analysis of variance. SETTING: A musculoskeletal research laboratory in a university teaching hospital. MATERIAL: Ten mature mixed-breed dogs. INTERVENTION: Unilateral implantation of total hip arthroplasty in the right femur with a Madreporic-surfaced prosthesis. Studies were conducted at 6 months in five dogs and at 24 months in five dogs. In each case, the nonoperated femur was the study control. MAIN OUTCOME MEASURES: Fluorescence microscopy analysis on comparable sections at four levels of the femora, percent porosity computed by image analysis, cortical atrophy. RESULTS: Cancellous hypertrophy was most prominent at the junction of the beaded and smooth portions of the femoral stem. At 6 months the cortex demonstrated atrophy predominant in the anteromedial quadrant. Active bone turnover was present within the interstices of the prosthesis at 6 and 24 months. No significant cortical bone loss occurred between 6 and 24 months. Stress transfer to the bone-prosthesis interface and endosteal cortical "cancellization" appear to be linked phenomena.

Animals↗

PubMed1994

A study of micromotion and appositional bone growth to a canine madreporic-surfaced femoral component.

A canine total hip arthroplasty model was used to examine micromotion and bone apposition to a proximally two-thirds madreporic-surfaced femoral prosthesis. Micromotion was also measured following initial press-fit implantation into canine cadaveric femora. After initial press-fit fixation and either 6 or 24 months of biologic fixation, micromotion was less than 23 microns in the proximal and midstem regions, a magnitude consistent with bone apposition. Bone apposition was greatest near the junction of the madreporic and smooth surfaces and was not significantly different between 6 and 24 months (51% at 6 months and 47% at 24 months). The quality of the interface tissue appears to be conductive to long-term fixation.

Animals↗

PubMed1992

The relationship between wrist position, grasp size, and grip strength.

In the first part of this study, the position assumed by a normal wrist during unconstrained maximal grip and the relationship between wrist position and grip strength were investigated in 20 healthy subjects. Grip strength and wrist position were recorded in the self-selected position and then again while the subjects voluntarily deviated the wrist randomly into flexion, extension, or radial or ulnar deviation of 10 to 15 degrees. The self-selected position was 35 degrees of extension and 7 degrees of ulnar deviation. Grip strength was significantly less in any position of deviation from this self-selected position, even after accounting for fatigue. With the wrist in only 15 degrees of extension or in neutral radio-ulnar deviation, grip strength was reduced to two thirds to three fourths of normal. Sex did not affect wrist position. The dominant wrists were within 5 degrees of the nondominant ones but were relatively less extended and in more ulnar deviation. Grip strength is significantly reduced when wrist position deviates from this self-selected optimum position. In the second part of the study, the effect of grasp size on this self-selected position was studied in 21 subjects. The degree of wrist extension was inversely and linearly related to how large a setting on the Jamar dynamometer was used. This was true regardless of hand size, although the effect was more significant for smaller hands. Radial and ulnar deviations were not affected by handle position. A minimum of 25 degrees of wrist extension was required for optimum grip strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Ipsilateral fractures of the distal radius and scaphoid treated by Herbert screw and external skeletal fixation. A report of two cases.

Two patients with comminuted, displaced fractures of the distal radius associated with ipsilateral, undisplaced scaphoid fractures were treated by internal fixation of the scaphoid fracture with a Herbert screw in association with external fixation of the distal radial fracture. One of the patients had a limited open reduction of the distal radius combined with bone grafting. Both patients had satisfactory results. Internal fixation of the scaphoid is indicated if distraction is applied to the carpus to treat an associated fracture of the distal radius, even if the scaphoid fracture is undisplaced.

Accidental Falls↗

PubMed1992

The effect of malunion on functional outcome after plate fixation of fractures of both bones of the forearm in adults.

Fifty-five adults who had a fracture of both bones of the forearm were managed with plating and were followed for a mean of six years (range, one year to sixteen years and two months) with functional and radiographic assessment. Malunion was quantified by measurement of the amount and location of the maximum radial bow in relation to the contralateral, normal forearm. Fifty-four of the radial and fifty-four of the ulnar fractures united. Eighty-four per cent of the patients had an excellent, good, or acceptable functional result, according to the criteria of Grace and Eversmann. Bone-grafting did not affect the rate of union. Restoration of the normal radial bow was related to the functional outcome. A good functional result (more than 80 per cent of normal rotation of the forearm) was associated with restoration of the normal amount and location of the radial bow (p less than 0.05 and p less than 0.005). Similarly, the recovery of grip strength was associated with restoration of the location of the radial bow toward normal (p less than 0.005).

Adolescent↗

PubMed1991

Polyethylene synovitis following canine total hip arthroplasty. Histomorphometric analysis.

The synovial membrane response to polyethylene wear debris was analyzed in canine total hip arthroplasties (THA). Fifty-four THAs were performed in healthy, mature dogs. None of the arthroplasties demonstrated clinical or radiographic signs of loosening. Synovial membrane biopsies were harvested 4 (n = 13), 6 (n = 5), 8 (n = 8), 12 (n = 15), and 24 (n = 6) months after surgery and were scored for inflammation, polyethylene (PE) wear debris, histiocyte density, and membrane thickness. The amount of PE wear debris tended to increase with time. However, the inflammatory changes within the joint capsule and synovial membrane did not progress, and the total thickness of the alveolar and surface layers decreased (P = .008). It appears that the amount of wear debris at 2 years in canine hip arthroplasties, without evidence of loosening, is well tolerated by the joint capsule.

Animals↗

PubMed1991

Soft-tissue blood flow after segmental osteotomy of the canine tibia.

The response of soft-tissue blood flow to a segmental osteotomy of the canine tibial diaphysis was investigated. Forty-three dogs underwent unilateral tibial osteotomies to create a 2.5-cm avascular diaphyseal segment, which was then rigidly stabilized with a plate. Blood flow measurements of the limbs that underwent surgery and control limbs were made using cerium 141 microspheres. One month after surgery, blood flow to the caudal musculature was increased 1.4-fold and at 2 and 3 months was twofold the value of the control side. The cranial musculature blood flow was 2.4-fold the control value at 1 month and 1.4-fold the control value at 2 and 3 months. Skin blood flow was significantly elevated at 1 month after surgery (p less than 0.0277), but by 2 and 3 months, skin flow had decreased to 1.4-fold and 1.3-fold of control values (p = 0.22). Bone marrow and cortical blood flows were still significantly elevated at 3 months after surgery. Muscle blood flow remains markedly elevated 3 months after surgery. This study demonstrates the importance of soft-tissue blood flow to the process of revascularization, remodeling, and incorporation of avascular cortical bone.

Animals↗

PubMed1991

A comparison of the effects of skin coverage and muscle flap coverage on the early strength of union at the site of osteotomy after devascularization of a segment of canine tibia.

A study was done to compare the effects of coverage with skin and those of coverage with a muscle flap on the early return of strength at the site of an osteotomy after interposition of a devascularized segmental autogenous graft, two centimeters long, from a canine tibia. The bone was fixed with a plate. Thirty-two animals were randomized into two groups, one of which was treated with skin coverage and the other of which was treated with muscle flap coverage. Half of the animals from each group were killed at eight weeks and half, at twelve weeks postoperatively. The tibiae were tested to failure in four-point bending. Failure occurred primarily through the site of the distal osteotomy. Maximum bending load (p = 0.0002) and energy absorbed to failure (p less than 0.02) increased significantly between eight and twelve weeks postoperatively in the group in which a muscle flap had been used for coverage. Bending stiffness was significantly greater at eight weeks in the group in which a muscle flap had been used for coverage than in the group in which skin had been used (p less than 0.03). Maximum bending load was also significantly increased at twelve weeks in the group in which a muscle flap had been used compared with the group in which skin had been used (p less than 0.05).

Animals↗

PubMed1991

Treatment of scaphoid nonunion by radical curettage, trapezoidal iliac crest bone graft, and internal fixation with a Herbert screw.

Ten adult male patients with scaphoid nonunions were treated by radical curettage, trapezoidal iliac crest bone grafting, and internal fixation with a Herbert screw. The mean patient age was 24.7 years, and the mean duration of the nonunion before surgery was 37.3 months. Mean follow-up time was 30.4 months. Nine of the ten nonunions healed, although one patient required a second bone-grafting procedure. The mean postoperative grip strength was 45.0 kg, and the mean postoperative pinch strength was 11.5 kg. The mean postoperative range of motion was volar flexion, 76.1 degrees; dorsiflexion, 74.2 degrees; radial deviation, 22.1 degrees; and ulnar deviation, 40.1 degrees. The scapholunate angle decreased from a mean of 72.8 degrees preoperatively to 60.6 degrees postoperatively (p less than 0.025). The mean carpal index was 0.57 postoperatively. Mean scaphoid length increased postoperatively and was within 0.2 mm of the opposite (normal) scaphoid in every patient except the single patient with a persistent nonunion (p less than 0.025). All patients returned to work (eight as laborers), and nine of ten wrists were subjectively rated as good or excellent. The results of the series suggests that treatment of displaced scaphoid nonunion by radical curettage, trapezoidal iliac crest bone grafting, and internal fixation with a Herbert screw is an effective method of treatment that reconstitutes scaphoid anatomy and promotes excellent wrist function.

Adult↗

PubMed1990

Internal fixation of a capitate fracture with Herbert screws.

A case of an isolated, displaced fracture of the capitate is described. This rare carpal injury was treated by internal fixation with two Herbert screws. The fracture united and the patient achieved an excellent range of wrist motion. The Herbert screw is useful in the treatment of displaced fractures of the capitate since the screw maintains reduction, compresses the fracture site, and allows early wrist motion.

Adult↗

PubMed1989

Effect of muscle flap coverage on bone blood flow following devascularization of a segment of tibia: an experimental investigation in the dog.

Severe tibial fractures may be associated with soft tissue loss, devascularization of cortical bone, and significant morbidity. Local rotational muscle flap coverage is used to obtain coverage of acute open tibial fractures and to treat chronic osteomyelitis of the tibia. The purpose of this study was to determine (a) the longitudinal and cross-sectional regional blood flow characteristics of the canine tibia and (b) whether a muscle flap was superior to vascularized skin coverage in restoring blood flow to devascularized canine tibial cortex. A 2.5-cm segment of tibia between two standardized osteotomies was devascularized. The segment was replaced anatomically and stabilized with a plate. The animals were divided into two experimental groups: (a) skin coverage (n = 8), and (b) muscle flap coverage (n = 8). Thirty-one days postoperatively Ce141 microspheres were injected to measure bone blood flow. The tibial diaphysis was divided into proximal, middle (devascularized), and distal segments. The unoperated leg was used as a control. In the control tibiae, the middle segment was less vascular than either the proximal or distal segment and no difference between anterior and posterior cortical blood flow was observed. Blood flow to the devascularized segment of tibia was significantly greater when it was covered with a muscle flap (p less than 0.025). The most significant increase in bone blood flow in the muscle flap coverage group versus the skin coverage group occurred in the anterior cortex of the tibia (p less than 0.005). This may be clinically important since the soft tissues over the anterior tibia are commonly deficient following open fractures.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Medial epicondylitis caused by injury to the medial antebrachial cutaneous nerve: a case report.

A 35-year-old man who had chronic elbow pain due to medial epicondylitis received a steroid injection into the medial epicondyle. This was followed immediately by increased pain and symptoms of dysesthesia in the distribution of the medial antebrachial cutaneous nerve. On surgical exploration 9 months later, the nerve was found to lie directly over the medial epicondyle and appeared to have sustained an injection injury. This report draws attention to the fact that because the posterior division of the medial antebrachial cutaneous nerve may lie directly over the medial epicondyle, it may be at risk of direct injury if injections are given into the epicondyle.

Adult↗

PubMed1989

Treatment of painful scapulothoracic crepitus by resection of the superomedial angle of the scapula. A report of three cases.

Three healthy young male manual laborers developed painful unilateral scapulothoracic crepitus arising from the superomedial angle of the scapula. There was a history of trauma in two of the patients. Asymmetric prominence of the superomedial angle of the scapula was demonstrated by computed tomography (CT) scanning in two patients. All three patients were successfully treated by resection of the superomedial angle of the scapula. The resected tissue was histologically normal in each case. Painful scapulothoracic crepitus arising from the superomedial angle of the scapula is associated with local trauma, is best investigated with a CT scan, and if unresponsive to prolonged conservative measures, can be successfully treated by resection of the superomedial angle of the scapula.

Adult↗

PubMed1988

Internal fixation of an unstable open fracture of a distal phalanx with a Herbert screw.

A 20-year-old patient was seen with an unstable, infected, open fracture of the distal phalanx of the long finger of the right dominant hand. The patient was treated by removal of the nail, debridement of the fracture site, and stabilization of the fracture with a Herbert screw. The Herbert screw compressed the fracture site and allowed early active motion of the distal inter-phalangeal (DIP) joint. The wound healed without incident, and the fracture was radiographically united 6 weeks after the procedure. The Herbert screw is useful in the treatment of unstable fractures of the distal phalanx, since the screw maintains reduction, compresses the fracture site, and allows early active motion of the DIP joint.

Adult↗

PubMed1988

Thoracic outlet syndrome with congenital pseudarthrosis of the clavicle: treatment by brachial plexus decompression, plate fixation and bone grafting.

Although a number of cases of congenital pseudarthrosis of the clavicle have been described in the literature, they provide little direction for the treatment of this condition when it is associated with thoracic outlet syndrome. The authors describe their experience with such a case in a 20-year-old woman. Symptoms of pain in the ulnar distribution of the right forearm and discoloration of the hand with abduction of the extremity had developed over 3 years. The radial pulse was obliterated by abduction of the arm. Exploration of the brachial plexus revealed a constricting band arising from the distal fragment of the clavicle running to the first rib which, together with the mass of the pseudarthrosis, comprised the thoracic outlet. The patient was successfully treated by division of the fibrous band, reduction of the clavicle, internal fixation with a plate and iliac crest bone grafting. At follow-up the patient had a full range of motion in the shoulder and was asymptomatic.

Adult↗

PubMed1988

Shoulder arthrodesis using a pelvic-reconstruction plate. A report of eleven cases.

Eleven adults who had a flail shoulder due to brachial plexus palsy had arthrodesis of the shoulder using a single ten-hole pelvic-reconstruction plate. Both the glenohumeral and the acromiohumeral joints were fused with the shoulder in the position of 30 degrees of abduction, 30 degrees of flexion, and 30 degrees of internal rotation. No bone graft was used. The patients were immobilized in a spica cast for six weeks postoperatively. At an average follow-up of twenty-five months after the operation, the position of the arthrodesis had been maintained and solid fusion had occurred in each shoulder. No patient required removal of the plate. The pelvic-reconstruction plate is malleable and is more easily contoured in the operating room than a dynamic-compression plate. We recommend the use of a malleable pelvic-reconstruction plate when performing arthrodesis of the shoulder.

Adult↗

PubMed1987

The influence of muscle flap coverage on the repair of devascularized tibial cortex: an experimental investigation in the dog.

Segments (2 cm) of canine tibial diaphyseal bone were devascularized and internally fixed with a plate. The medial cortex of the devascularized tibia was covered with skin in one experimental group (n = 7) and a local muscle flap in the other (n = 6). The animals were given intravenous fluorochrome dye and killed 42 days postoperatively. Enveloping callus formed around the cortex which was repaired by the formation of resorptive cavities on its external surface. New bone formation occurred within the resorptive cavities. Muscle flap coverage was associated with a sixfold increase in cortical porosity (p less than 0.005) and a fourfold increase in the area of enveloping callus (p less than 0.05). The area of intracortical new bone formation was greater in the cortex with muscle flap coverage (p less than 0.05). The maximum depth of intracortical new bone formation increased from 0.46 +/- 0.14 mm with skin coverage to 0.95 +/- 0.14 mm with muscle flap coverage (p less than 0.001). This study demonstrates that muscle flaps are superior to skin coverage in initiating the repair of devascularized cortical bone.

Animals↗