Biomedical subjects
Publications and source records attributed to W F Blair.
Rupture of finger extensor tendons by attrition is an extremely rare complication of Madelung's deformity. We report a case of bilateral rupture in a previously symptom-free woman. The dorsally subluxed distal ulna was resected to prevent further rupture. The mechanism of injury, clinical and radiographic features, and treatment of this uncommon complication are reviewed.
A thorough knowledge of anatomy, injury patterns, repair techniques, and evolving rehabilitation methods is necessary to best treat extensor tendon injuries. These injuries are conceptualized as occurring in one of eight zones, which are numbered distally to proximally in the hand and forearm. Even though surgical technique and rehabilitation are specific in each zone, injuries over and proximal to the proximal interphalangeal joint tend to yield less satisfactory results. Dynamic postoperative extension splinting is one factor that is improving long-term results.
Digital periarterial sympathectomy was performed on 11 digits in three patients with chronic digital ischaemia which was a manifestation of either Raynaud's disease, C.R.E.S.T. syndrome or traumatic ulnar artery thrombosis. Before operation, all patients had pain in the affected fingers and five digits had ulcers, two of which were infected. Using the operating microscope, the adventitia was stripped circumferentially over the distal 2 cm. of the common digital arteries, the bifurcation and the proximal 1 cm. of the proper digital arteries distal to the bifurcation. The same procedure was repeated, at the wrist level, for the ulnar artery and/or the radial artery and its dorsal branch. Follow-up ranged from three to 16 months. After two weeks, all patients reported relief of pain and the ulcers were progressively healing. By three months, all ulcers had healed.
This study retrospectively analyzes primary flexor pollicis longus repairs. Ninety-four patients were identified and had extensive chart review. Thirty patients returned for follow-up (mean of 6.8 years) interview, range of motion, and strength testing. At follow-up, interphalangeal active range of motion, metacarpophalangeal active range of motion, and carpometacarpal active range of motion was 68 degrees, 48 degrees, and 46 degrees, respectively. Comparisons between active range of motion for the injured and noninjured hands revealed percentage differences of 71, 82, and 96% for the interphalangeal, metacarpophalangeal, and carpometacarpal joints. The percentage differences between active range of motion and passive range of motion for the injured metacarpophalangeal and interphalangeal joints were 71% and 75%. Injured thumbs had averages of 6.7, 7.0, 5.4, and 30.6 kg for the key, chuck, thumb-index pinches and JAMAR grip mean. The percentage differences of injured to uninjured hands in these tests were 91%, 84%, 92%, and 92%. Factors that appear to have a consistently negative effect on outcome include mechanism of injury and associated damage. Factors that did not uniformly affect outcome included zone of injury, age, sex, and postoperative splinting.
Technical advances in twenty MHz pulsed ultrasonic Doppler velocimetry (PUDVM) permit increasingly accurate measurements of blood flow in small vessels. This study applied advanced twenty MHz PUDVM methods to the transcutaneous, noninvasive quantitation of blood flow in arteries of the human hand. One hundred forty-four measurements were completed bilaterally in the digital arteries of all fingers and in the distal radial and ulnar arteries of the forearm. The data were averaged by artery for maximum velocity and average volumetric flow. The maximum velocity for digital and forearm arteries was about 20 centimeters per second and 50 centimeters per second, respectively. The average volumetric flow for these same arteries was about 0.02 cubic centimeters per second and 0.18 cubic centimeters per second, respectively. Statistical analysis demonstrated no differences between paired, contralateral arteries; within given fingers a difference occurred only between the radial and ulnar arteries of the index finger.
This study measured the hemodynamics of peripheral arterial sites in the rat, using 20 MHz pulsed ultrasonic Doppler velocimeter (PUDVM) methods. The lower extremities of 14 male Sprague-Dawley rats were studied. The targeted sites included the abdominal aorta, external iliac, proximal femoral, mid-femoral, and saphenous arteries. The hemodynamic variables of pulse period, maximum centerline velocity, lumen diameter, and mean volumetric flow were calculated interactively from temporal-spatial plots of local velocity distributions. An analysis of variance revealed significant differences between right and left sides for lumen diameter (P = 0.028) and mean volumetric flow (P less than 0.0001). The analysis showed no statistical difference for pulse period (P = 0.0836) among sites. However, three distinct groupings of sites: 1) abdominal aorta, 2) external iliac, proximal femoral, and mid-femoral arteries, and 3) saphenous artery were noted for the remaining hemodynamic variables (P less than 0.05). These results indicate that three hemodynamically distinct regions are available for microvascular research in the rat lower extremity arterial tree.
A retrospective analysis was done in 62 patients with 101 digits having extensor tendon injury. Quality of outcome and parameters that might influence outcome were evaluated. The majority of patients were treated with conventional static splinting. Sixty percent of all fingers sustained an associated injury (fracture, dislocation, joint capsule or flexor tendon damage). Patients without associated injuries achieved 64% good/excellent results, and total active motion of 212 degrees. This difference was statistically significant (p less than 0.05). Distal zones (1 to 4) had a significantly poorer result than more proximal zones (5 to 8). The percentage of fingers losing flexion was greater than the percentage of fingers losing extension. In addition, the average degree loss of flexion was greater than the average degree loss of extension. This would seem to indicate that loss of flexion may be a more significant complication from extensor tendon injury than previously thought.
In 1986, The American Association for Hand Surgery and the American Society for Surgery of the Hand jointly sponsored a Role Delineation Study of Hand Surgery. The purpose of this study was to define the knowledge and skills necessary for competent hand surgery practice and to determine the responsibilities and activities of hand surgeons. Eight hundred thirty-eight hand surgeons returned a self-report questionnaire. This questionnaire was designed to collect information relative to the demographic characteristics of the respondents, the importance of 38 surgical procedures, and 60 categories of knowledge related to hand surgery, and to elicit respondents opinions regarding certification in hand surgery. This study is a first attempt to define the domain of hand surgery. The data collected in this study provide the basis for designing residency fellowship and continuing education programs and may also be used to study manpower needs, regional variations in practice patterns, and to identify the educational needs of the profession of hand surgery.
We describe a prospective, long-term evaluation of the Schultz metacarpophalangeal joint implant. The prosthesis is a semiconstrained, cemented implant with a ball-in-socket articulation. Thirty-six implants were followed for an average of 10.9 years. There was a progressive decrease in range of motion and strength and a recurrence of ulnar deviation. The neck of the proximal phalangeal component fractured in 39% of the joints. Periarticular heterotopic bone formed in all joints, but was extensive in only 22%. Although some lucency of the bone-cement interface was seen in 80% of the joints, no prosthetic loosening occurred in this series. Our results indicate that long-term, intramedullary cement fixation of relatively long-stemmed components can be satisfactory. However, the articulated portion of this implant does not consistently withstand the stresses transmitted across the joint and does not provide long-term joint stability.
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This study quantitatively assesses the hemodynamic consequences of inserting a 1.5-mm polyethylene anastomotic device in both small arteries and veins. The device was placed in 20 rabbit femoral arteries and 20 femoral veins. Using 20-MHz pulsed ultrasonic Doppler velocimetry techniques, blood flow was measured in 5 immediate postoperative intervals and at the 24-hour and 3-week postoperative intervals. In arteries, volumetric flow (Q) was not statistically different in any postoperative interval; maximum spatial velocity (Vmax) was significantly increased in the immediate postoperative intervals but was not different at 24 hours or 3 weeks. In veins, significant decreases in Q and increases in Vmax occurred in the immediate postoperative intervals, but differences were not noted at the 24-hour or 3-week intervals. The results of this study indicate that the hemodynamic consequences of anastomosing small vessels with a polyethylene device are minimal and that this mechanical technique is an effective method for experimental microvascular repairs.
This study analyzes the histology associated with the polyethylene ring-pin device. The device was placed in 20 rabbit femoral arteries and 20 femoral veins. Specimens were harvested at 24-hour and 3-week postoperative intervals and were analyzed using light, scanning electron, and transmission electron microscopy. Generally, the reparative process in the arteries and veins was similar. In 24-hour artery and vein specimens, the endothelial cells were absent, the media tapered within the device, but smooth muscle cells (SMC) remained partially viable. In 3-week specimens, the device junction was well healed and reendothelialized. Subintimal hyperplasia was present, the internal elastic lamina was not reconstituted, and the SMCs were partially viable. Small vascular channels formed at the device junction, and small venous valves were noted near the device. Macrophages lined the margins of the device. The early reparative process proceeds favorably, by histologic criteria, after vessel repair with the polyethylene ring-pin device.
This study compared three commonly used methods of measuring ulnar variance. The comparison included the project- a-line technique (A), the method of concentric circles (B), and the method of perpendiculars (C). Specific features studied were variations in results generated by each technique as well as the interobserver and intraobserver reliability for each technique. The only significant difference among techniques was between techniques A and B (p = 0.0224), where mean A values were more positive than mean B values. Observers were found to differ significantly (p = 0.0092) independent of technique. All methods studied were highly reliable, although the method of perpendiculars was most reliable for both interobserver (reliability = 0.9801) and intraobserver (reliability = 0.9719) reliability. This study shows that the clinician may choose whichever technique he prefers when measuring ulnar variance.
Lipoma in the deep palmar space of the hand is an unusual tumor. Our experience with seven of these tumors indicates that they can be unusually large at initial examination, can first be seen with paresthesias in branches of the median nerve, and can be difficult to surgically expose. Marginal resection of this tumor is curative.
A retrospective analysis of the long-term results of the crossed intrinsic transfer operation is presented. Twenty-one patients (30 hands) with rheumatoid arthritis and one patient (1 hand) with systemic lupus erythematosus were examined clinically and radiographically. The average follow-up was 12.7 years. The average postoperative ulnar drift for all fingers was 5 degrees. The magnitude of ulnar drift did not increase over time. The average active range of motion for the metacarpophalangeal joints was 47 degrees and for the proximal interphalangeal joints it was 58 degrees. The average radial deviation deformity of the wrist in the resting position was 2 degrees. These variables did deteriorate with time. Extensor carpi radialis longus to extensor carpi ulnaris tendon transfer with crossed intrinsic transfer produced the same result as crossed intrinsic transfer alone. The outcomes for crossed intrinsic transfer attached to the lateral band were similar to outcomes for transfers attached to the collateral ligament of the metacarpophalangeal joint. The crossed intrinsic transfer procedure effectively provides long-term correction of ulnar drift in the rheumatoid hand.
The failure rates for total elbow arthroplasty, in comparison to those for hip arthroplasty, are quite high, and a precise understanding of the underlying causes still remains elusive. The presence of abnormal stresses is a known factor that accelerates loosening of hip and knee arthroplasties. Although a large number of biomechanical studies have led to a better understanding of elbow joint kinetics, very little is known about the stress distribution in this joint. The implantation of a Coonrad humeral component increases stresses in the bone and cement adjacent to the stem tip and hinge regions. An analysis of implanted ulnar stresses and a comparison of those stresses to implanted humeral stresses would improve our understanding of hinged elbow arthroplasty. For this reason, the distribution of mechanical stresses in the ulna are investigated in this study. Using a specially developed casting and sectioning technique, three-dimensional finite element meshes were obtained from an intact human cadaver ulna and an ulna fitted with a Coonrad prosthesis. The material properties were derived from values presented in the literature. Stress distributions in response to axial compression, axial torque, and anteroposterior (AP) force were computed. The cancellous bone and cement regions adjacent to the stem tip of the prosthesis exhibited higher stresses than those in the same regions of the intact case. The higher stresses in the ulna with an implanted prosthesis, as compared to the intact model, might initiate loosening or failure of the prosthesis. The stresses in the cortical bone region adjacent to the prosthesis head were decreased. This is consistent with the clinical observations of bone atrophy following total elbow arthroplasty.(ABSTRACT TRUNCATED AT 250 WORDS)
Pulsed ultrasonic Doppler velocimetry (20 MHz) (PUDVM) has evolved considerably in the last 10 years. Engineering development has resulted in a computer-controlled vessel-scanning instrument whose backscattered frequency shift spectra are analyzed using fast Fourier transforms (FFT). Benchtop and theoretic studies indicate accurate (error less than 5%) velocity and volumetric flow rate measurements in vessels with a lumen diameter as small as 1.2 mm. Clinical application of the PUDVM has provided transcutaneous measurements of blood flow variables in normal human digital arteries. Experimental application to arteries 1.0-1.5 mm has provided information on the hemodynamic effects of topical vasodilators, standard microarteriorrhaphy, variations in microvascular technique, interpositional grafts, and early wound repair. With improving computer capabilities and technical modifications, the PUDVM will be an increasingly important tool in clinical and experimental microsurgery.
This paper describes an experimental investigation to determine the biomechanical efficacy of the extensor carpi radialis longus (ECRL) to extensor carpi ulnaris (ECU) tendon transfer procedure used in rheumatoid hand reconstruction. Six normal cadaver specimens were tested in an apparatus that measured (a) the forces acting on the hand to restrain it in seven characteristic wrist configurations, and (b) the amount of hand pronation/supination that occurred as a result of loads applied to the tendons of the six major wrist muscles. Each specimen was tested with the ECRL tendon intact, surgically released, and transferred to the insertion point of ECU. In the intact and transferred states, the ECRL tendon was loaded sequentially while the remaining five wrist tendons were subjected to equal constant loads. In all three experimental ECRL test states, forces were also applied to all intact wrist tendons in a manner designed to represent physiologic load sharing. When the ECRL tendon was loaded sequentially, the transfer resulted in the predictable increase in the radially directed restraining force and the predictable supination of the hand relative to the forearm. When all intact tendons were loaded physiologically, the transfer also resulted in an increase in the radially directed restraining force. Significant differences between test states occurred generally only between the intact and release states of the ECRL tendon and not between release and transferred states.(ABSTRACT TRUNCATED AT 250 WORDS)