Relationship between joint motion and flexor tendon force in the canine forelimb

To increase in vivo tendon force and gliding after flexor tendon repair, a variety of modifications to the methods by which protective passive motion is administered have been advocated. To determine the relationship between the prime variables, wrist and digital position, muscle activation, and in vivo tendon force, a clinically relevant canine model was developed. Force was measured in the flexor tendon during several joint manipulation paradigms: single-finger flexion-extension with the wrist flexed (group 1F), single-finger flexion-extension with the wrist extended (group 1E), four-finger flexion-extension with the wrist flexed (group 4F), four-finger flexion-extension with the wrist extended (group 4E), and synergistic wrist and finger motion where wrist extension and finger flexion were performed simultaneously, followed by wrist flexion and finger extension (group SYN). In addition, tendon force was measured during electric stimulation of the proximal flexor muscle mass. Passive tendon force with the wrist extended (groups 1E and 4E) was two to three times greater than that measured with the wrist flexed, independent of the number of digits moved. With the wrist extended, peak tendon force reached 1,997 g +/- 194 g during single-digit manipulation (group 1E), compared to only 853 g +/- 104 g with the wrist flexed during the same maneuver (group 1F). Statistical comparison between means revealed that groups 1E and 4E were significantly different from groups 1F, 4F, and SYN (p < .005). There were no significant differences between groups 1E and 4E or between groups 1F, 4F, and SYN (p > .200). Active muscle force elicited by electrical stimulation and passive force varied dramatically as the wrist was flexed from full extension 3460 g +/- 766 g to full flexion 427 g +/- 239 g (p < .001). Simultaneously, passive tension decreased from 940 g +/- 143 g with wrist extended to 76 g +/- 37 g with the wrist flexed. These data indicate that wrist position has the greatest effect on flexor tendon force during motions that are commonly used to rehabilitate flexor tendon repairs. Thus, if force is to be controlled during passive motion, wrist-joint angle will have the dominant effect, while the number of digits manipulated will have much less of an effect. If the clinical goal is to minimize tendon force, rehabilitation could be carried out with the wrist flexed, whereas if the goal is to increase tendon force, rehabilitation could include exercise programs that use a greater degree of wrist extension.

Carpal tunnel release. Correlations with preoperative symptomatology

Fifty patients (54 hands) who underwent carpal tunnel release for carpal tunnel syndrome were evaluated to determine the relationship between the prominence of specific clinical symptoms and the early results of carpal tunnel release. Patients were evaluated preoperatively, 3 weeks after surgery, and 3 months after surgery by questionnaire, physical examination, and Semmes-Weinstein monofilament pressure testing. The symptoms evaluated included hand/wrist/forearm pain, night pain/paresthesias, intermittent paresthesias, hand clumsiness, hand weakness, constant numbness, and difficulty with work related tasks. All symptoms showed significant improvements at 3 months after surgery. Overall symptom reduction at 3 months after surgery was 49% +/- 73%. Overall satisfaction at 3 months after surgery was 7.8 +/- 2.8 (0 to 10 scale). the severity of preoperative subjective hand weakness was significantly associated with surgery and with less improvement of function at 3 months after surgery and with less satisfaction with overall symptom relief at 3 months after surgery. Although subjective outcomes in this study were markedly improved after carpal tunnel release regardless of preoperative symptomatology, patients with more preoperative night symptoms and intermittent paresthesias and less preoperative hand/wrist pain, numbness, weakness, clumsiness, and difficulty with work related tasks were the most satisfied with their surgery.

Radiographic assessment of the trapezial space before and after ligament reconstruction and tendon interposition arthroplasty

A radiographic method was developed, the trapezial space ratio, for assessing the space occupied by the trapezium (a space defined by the distal scaphoid and thumb metacarpal base divided by the thumb proximal phalanx). This method was applied to 100 normal thumb radiographs and to the radiographs of 15 patients with symptomatic degenerative arthrosis of the thumb basal joint before and after operative treatment with ligamentous reconstruction and tendon interposition arthroplasty. The trapezial space ratio averaged 0.476 +/- 0.033 for radiographs of normal thumbs, 0.372 +/- 0.084 for the pre-operative radiographs of thumbs with symptomatic basal joint arthrosis, and 0.270 +/- 0.078 for the radiographs of thumbs following basal joint arthroplasty. A significant reduction in the trapezial space ratio was noted when values from arthritic thumbs were compared to those of normal thumbs (22%; P < 0.0001). A further reduction in the trapezial space ratio was noted when post-operative values were compared to pre-operative ones (27%; P < 0.0002). Comparing post-operative trapezial space ratio values to values obtained in normal thumbs, a reduction of 43% was found in those thumbs treated operatively. These finding indicate that the trapezial space is reduced significantly in thumbs with severe degenerative arthrosis compared to normal thumbs and that ligament construction tendon interposition arthroplasty is not entirely successful in either restoring or maintaining the length of the thumb ray.

Basal joint arthritis: trapeziectomy with ligament reconstruction and tendon interposition arthroplasty

This article provides a qualitative and quantitative outcomes assessment of a consecutive series of 27 patients (30 thumbs) with basal joint arthritis of the thumb undergoing ligament reconstruction and tendon interposition arthroplasty. Outcome analysis revealed that 24 (89%) patients were satisfied with the relief of pain provided by the arthroplasty and 23 (87%) would undergo surgery again. Eighteen (67%) thumbs were noted to have improvement in the ability to perform activities of daily living. Significant improvements were noted in web space measurements and in grip and pinch strength determination. X-ray film assessment using the trapezial space ratio averaged 0.33 +/- 0.08 in preoperative x-ray films of thumbs with stage III and IV degenerative arthritis and 0.23 +/- 0.07 in thumbs following basal joint arthroplasty. This represents a total decrease of 51% in the trapezial space ratio following arthroplasty compared to the normal values obtained in previous studies and 33% compared to the preoperative values obtained in this study. Outcomes assessment at a mean of 42 months after surgery showed that there was no significant correlation between maintenance of trapezial height and both objective and subjective clinical outcomes. Although ligament reconstruction consistently failed to restore trapezial height, primary and secondary clinical outcomes following basal joint arthritis were almost uniformly satisfactory.

Dynamic scapholunate instability: results of operative treatment with dorsal capsulodesis

Nineteen patients underwent 20 dorsal capsulodesis for dynamic scapholunate instability. Seventeen patients (18 wrists) were evaluated by a questionnaire and physical examination after a mean postoperative follow-up period of 34 months (range, 12-65). The diagnosis was based on a combination of characteristic symptoms of scapholunate instability and physical findings consisting of dorsal wrist tenderness at the scapholunate interval and a positive scaphoid shift test. Following surgery, a significant decrease was noted in symptoms of pain and clunking. Functional status was improved postoperatively; the most significant gains were seen in opening jars, sweeping, shoveling, and throwing. Fifteen of 17 patients returned to their original occupations, although 7 of those who returned to their original occupations did so with some restrictions. Objective evaluation by physical examination revealed a significant improvement in wrist stability as determined by the scaphoid shift test, and an average loss of 12 degrees of flexion. Fifteen of 17 patients (16 of 18 wrists) stated that they would undergo the surgery again if faced with the same choice. Our data demonstrate that dorsal radioscaphoid capsulodesis of the wrist in patients with dynamic scapholunate instability provides substantial improvement over preoperative status.

Growth factors and canine flexor tendon healing: initial studies in uninjured and repair models

The role of growth factors in a variety of bone and soft tissue healing processes has been studied extensively in numerous recent models, yet little is known about the specific growth factors that may be playing a role in flexor tendon healing. We used a number of established protein purification techniques and bioassays to isolate and partially characterize a heparin-binding growth factor from unoperated canine tendons. Our data provide evidence that basic fibroblast growth factor, a potent angiogenic growth factor, is present in normal canine intrasynovial flexor tendons. We then studied repaired canine flexor tendons to further elucidate the role of growth factors in the tendon healing process. Heparin-sepharose elution profiles from three repair intervals (3, 10, and 17 days) were graphed and compared to known profiles of isolated growth factors. The three repair intervals demonstrated two elution profile peaks, consistent with varying amounts of platelet-derived growth factor and epidermal growth factor. Although additional experimentation is required to identify definitively the various protein isolates, these data provide compelling evidence that a variety of growth factors are present in uninjured and healing digital flexor tendons.

Autogenous intrasynovial and extrasynovial tendon grafts: an experimental study of pro alpha 1(I) collagen mRNA expression in dogs

On the basis of recent evidence that the healing processes of tendon grafts are donor-tissue specific, in situ hybridization, using a 372 bp cDNA fragment complementary to a portion of pro alpha 1(I) collagen mRNA, was utilized to compare the cellular responses to transplantation exhibited by autogenous intrasynovial and extrasynovial flexor tendon grafts. Intrasynovial and extrasynovial tendons from the hindpaw were transferred to synovial sheaths in the forepaw of 12 mongrel dogs (24 tendons) and treated with immediate controlled passive motion. The tendon grafts were harvested at 2, 4, and 6 weeks, and each was divided into a proximal, central (8 mm), and distal portion. Sections from the central portion were embedded in paraffin and subjected to in situ hybridization, autoradiography, and staining; levels of procollagen mRNA then were assessed by microscopic examination. The two types of tendon grafts exhibited different levels of pro alpha 1(I) collagen mRNA expression at all three time points. Intrasynovial tendon grafts displayed no areas of increased type-I procollagen mRNA at 2, 4, and 6 weeks. The extrasynovial tendon grafts displayed increased surface levels of type-I procollagen mRNA at 2 and 4 weeks; the levels decreased to background levels by 6 weeks. The high levels of procollagen mRNA exhibited by the extrasynovial grafts suggest increased collagen synthetic activity, indicative of a cellular response to injury, whereas the preservation of low levels of expression in the intrasynovial grafts may signify a less inflammatory cellular response.

The flexor digitorum longus: an anatomic and microscopic study for use as a tendon graft

Recent experimental studies have shown that intrasynovial donor tendons have the capacity to heal with minimal alteration in the gliding surface when grafted to an intrasynovial location. In order to evaluate the flexor digitorum longus of the foot as a potential matched donor tendon for use in flexor tendon grafting, we dissected 15 feet (75 toes) and 10 hands (50 fingers) to determine the intrasynovial lengths of the flexor digitorum longus and flexor digitorum profundus and to determine a method of tendon graft harvest. Specimens were taken from the intrasynovial portion of each tendon for evaluation by light and electron microscopy. The intrasynovial tendons of the hand and foot were similar in vascularity, cellularity, gliding surface, and ultrastructure. The flexor digitorum longus tendon of the foot was a mean length of 12 cm to the area of tendon confluence in the midfoot, which will usually provide enough tendon length for grafting from the distal phalanx to the palm of the hand. Because of the difference in length of the synovial sheaths of the fingers and toes, some extrasynovial tendon will be transferred to the synovial space when a flexor digitorum longus tendon is used.

Aneurysmal bone cyst involving the lunate

Aneurysmal bone cysts are rare lesions which even more rarely involve the bones of the hand. We report a case of a cyst involving the lunate which was initially mistaken for interosseous ganglion. Due to delay in diagnosis, marked destruction of the lunate occurred, necessitating excision and scapho-capitate arthrodesis. Although rare, aneurysmal bone cysts should be included in the differential diagnosis and ruled out prior to embarking on a course of treatment.

Autogenous flexor tendon grafts: fibroblast activity and matrix remodeling in dogs

To investigate rates of cellular proliferation and matrix turnover in autogenous flexor tendon grafts, hindlimb intrasynovial (flexor digitorum profundus) and extrasynovial (peroneus longus) tendons were placed within the synovial sheaths of the medial and lateral forepaw digits of 18 dogs and treated with controlled early passive motion. After the dogs had been killed, short-term culture and labeling in vitro were utilized to determine rates of DNA, proteoglycan, collagen, and noncollagen protein synthesis. Schiff base covalent collagen crosslink concentrations and total collagen and protein content also were evaluated at intervals through 6 weeks. Tendon grafts of extrasynovial origin showed greater rates of DNA synthesis and significantly elevated levels of proteoglycan, collagen, and noncollagen protein synthesis and Schiff base covalent collagen crosslink concentrations (dihydroxylysinonorleucine) compared with intrasynovial tendon grafts. It was not clear to what extent the increased activity in the extrasynovial graft was due to actual differences between the intrasynovial and extrasynovial tendons or to the responses of the connective tissue surrounding the extrasynovial tendon graft. Since both types of grafts demonstrated similar unaltered levels of collagen and protein content over time, these data suggest greater rates of matrix turnover in tendon grafts of extrasynovial origin than in those of intrasynovial origin. Coupled with previous findings showing increased cellular proliferation in extrasynovial tendon grafts, these data indicate that the process of translation to an intrasynovial environment necessitates a more active process of soft-tissue repair and remodeling when extrasynovial donor tendons are used.

Responsiveness of self-reported and objective measures of disease severity in carpal tunnel syndrome

Responsiveness, the ability to detect meaningful clinical change, is a critical attribute of instruments used to evaluate outcomes of treatments. The authors hypothesized that self-administered symptom severity and functional status questionnaires are more responsive to clinical improvement after carpal tunnel release than traditional physical examination measures of strength and sensibility. Data were obtained from a randomized clinical trial of endoscopic versus open carpal tunnel release conducted in four university medical centers. Patients were evaluated before surgery and 3 months after surgery. Seventy-four patients indicating that they were more than 80% satisfied with the results of surgery were assumed to have clinically meaningful improvement and were the focus of the analysis. Evaluations included questionnaires assessing symptom severity, functional status, and activities of daily living as well as measurement of grip, pinch, and abductor pollicus brevis strength, and 2-point discrimination and Semmes-Weinstein pressure sensibility. Responsiveness was calculated with the standardized response mean (mean change/standard deviation of change) as well as the effect size (mean change/standard deviation of baseline values). The symptom severity scale was four times as responsive, and the functional status and activities of daily living scales were twice as responsive, as the measures of strength and sensibility. Self-administered symptom severity and functional status scales are much more responsive to clinical improvement than measures of neuromuscular impairment and should severe as primary outcomes in clinical studies of therapy for carpal tunnel syndrome.

Predictors of neurovascular displacement in hands with Dupuytren's contracture

A prospective study of hands with Dupuytren's contracture was designed to test the association of three variables, the presence of an interdigital soft tissue mass, the presence of flexion contractures at each digital joint, and the duration of contracture, with the formation of spiral nerves. 66 digits in 37 hands affected by Dupuytren's disease were examined intra-operatively. Of the 34 digits (52%) with spiral nerves, 28 had soft tissue masses (42%). The sensitivity of a soft tissue mass alone as a predictor of a spiral nerve was 59% and the specificity 75%. The presence of a flexion contracture at the PIP joint had a sensitivity of 88% and a specificity of 62% for the presence of a spiral nerve. The combination of a soft tissue mass and a PIP joint contracture was a very specific (94%) but not a particularly sensitive (50%) test for spiral nerve formation. The formation of a spiral nerve is progressive, occurring most often in hands with significant PIP joint contractures with or without soft tissue interdigital masses.

A preliminary scoring system for assessing the outcome of carpal tunnel release

Multiple outcomes are assessed in most studies of carpal tunnel syndrome, yet there are no validated methods of synthesizing these distinct measures into a single global score. We report a global score in which outcomes were selected and weighted according to their independent association with patient satisfaction with the results of surgery. Preoperative and 3-month follow-up data were analyzed on 104 subjects in a randomized controlled trial of open vs endoscopic carpal tunnel release. Patient satisfaction with surgery and a variety of subjective and objective outcome parameters were measured. In multivariate analyses, independent correlates of dissatisfaction included persistent numbness and paresthesia, incisional pain at follow-up evaluation, and decrease in grip strength. A global score was calculated by rounding to the nearest integer the model coefficients for these three variables. The global score correlated with patient satisfaction with surgery and time until return to work or full activities in patients undergoing open carpal tunnel release.

Variations in cellular proliferation and matrix synthesis in intrasynovial and extrasynovial tendons: an in vitro study in dogs

Intrasynovial and extrasynovial flexor tendon grafts recently have been shown to have dissimilar patterns of cellular survival and host integration within the digital sheath. In an effort to determine if fundamental differences exist between these two types of tendons, we investigated the biochemical composition and cellular activity of intrasynovial and extrasynovial tendon segments of 12 adult mongrel dogs in short-term explant culture in MCDB 105 and in DMEM media. Proteoglycan, collagen and noncollagen protein synthesis and content and DNA synthesis were determined following culture in both media. Intrasynovial tendon segments cultured in MCDB 105 medium synthesized significantly less collagen, noncollagen protein, and DNA and had similar amounts of proteoglycans compared to extrasynovial tendons. Comparison of intrasynovial and extrasynovial tendon segment responses in DMEM medium showed that intrasynovial tendons synthesized more proteoglycan, protein, and DNA than they did in MCDB 105. Extrasynovial tendons had similar rates of matrix component and DNA synthesis in both media. Findings that the synthesis of matrix components and DNA between intrasynovial flexor and extrasynovial peroneal tendon segments differ significantly indicate that intrasynovial flexor tendons may be specially adapted to the nutritional milieu provided by an intrasynovial environment. These data are supported by the selective successful stimulation of fibrocartilaginous segments within intrasynovial flexor tendons in media favored for the culture of cartilaginous tissue.

Evaluation of limb compartment with suspected increased interstitial pressure. A noninvasive method for determining quantitative hardness

Six compartments in four dogs and three compartments in three anatomic specimen limbs were injected with plasma, and the intracompartmental interstitial pressure and hardness of the compartments were measured. Six patients suspected of having compartment syndromes were also studied. Of the compartments evaluated in the dog and anatomic specimen limbs, the average correlation coefficient between measurements with the two methods was 0.95 (range, 0.87 to 0.99). In six patients suspected of having compartment syndromes, the ratios of quantitative hardness of the injured to uninjured limbs closely matched the intracompartmental interstitial pressure measurement ratios (correlation coefficient, 0.95). All correlation coefficients were significant (F test, p < 0.05). There was a close correlation between the direct measurement of intracompartmental interstitial pressure with the wick catheter and quantitative hardness in compartment syndrome models in dog and anatomic specimen limbs, and in patients suspected of having compartment syndromes. The determination of surface hardness of limb compartments, which appears accurate and reproducible, offers the advantages of being noninvasive and well suited for longer-term assessments of intracompartmental interstitial pressure.

Cellular survival and proliferation in autogenous flexor tendon grafts

In order to investigate fibroblast survival and proliferation in autogenous flexor tendon grafts, hindlimb intrasynovial and extrasynovial donor tendons were placed within the synovial sheaths of the medial and lateral forepaw digits of 21 dogs (42 tendons) and treated with controlled early passive motion. Intravital histologic evaluations with confocal microscopy and biochemical determinations of total DNA content and DNA synthesis were carried out at 10 days, 3 weeks, and 6 weeks. Intravital staining of the extrasynovial tendon grafts demonstrated variable degrees of cellular necrosis at the earliest intervals followed by cellular repopulation with fibroblasts and neovascularization from surface vessels. In contrast, intrasynovial tendon grafts were populated predominantly by viable cells at each interval, with occasional patches of cell necrosis and fibroblast ingrowth. Total DNA content and DNA synthesis values in the intrasynovial donor tendons were significantly lower than those seen in the extrasynovial tendon grafts at each interval. Extrasynovial tendons appear to act as scaffolds, undergoing extensive cellular death followed by a rapid repair response. Findings that intrasynovial tendon fibroblasts survive the tendon grafting process suggest that the nutritional supplies and metabolic requirements of intrasynovial and extrasynovial donor tendons differ largely.

Effects of local compression on peroneal nerve function in humans

A new apparatus was developed to compress the anterior compartment selectively and reproducibly in humans. Thirty-five normal volunteers were studied to determine short-term thresholds of local tissue pressure that produce significant neuromuscular dysfunction. Local tissue fluid pressure adjacent to the deep peroneal nerve was elevated by the compression apparatus and continuously monitored for 2-3 h by the slit catheter technique. Elevation of tissue fluid pressure to within 35-40 mm Hg of diastolic blood pressure (approximately 40 mm Hg of in situ pressure in our subjects) elicited a consistent progression of neuromuscular deterioration including, in order, (a) gradual loss of sensation, as assessed by Semmes-Weinstein monofilaments, (b) subjective complaints, (c) reduced nerve conduction velocity, (d) decreased action potential amplitude of the extensor digitorum brevis muscle, and (e) motor weakness of muscles within the anterior compartment. Generally, higher intracompartmental pressures caused more rapid deterioration of neuromuscular function. In two subjects, when in situ compression levels were 0 and 30 mm Hg, normal neuromuscular function was maintained for 3 h. Threshold pressures for significant dysfunction were not always the same for each functional parameter studied, and the magnitudes of each functional deficit did not always correlate with compression level. This variable tolerance to elevated pressure emphasizes the need to monitor clinical signs and symptoms carefully in the diagnosis of compartment syndromes. The nature of the present studies was short term; longer term compression of myoneural tissues may result in dysfunction at lower pressure thresholds.

Carpal tunnel release. A prospective, randomized assessment of open and endoscopic methods

To define the role of two-portal endoscopic carpal-tunnel release as a method for the treatment of compression of the median nerve at the wrist, a prospective, randomized, multicenter study was performed on 169 hands in 145 patients. Either open or endoscopic carpal-tunnel release was performed in all of the patients who had clinical signs and symptoms consistent with carpal tunnel syndrome, had not responded to or had refused non-operative management, and had had electrodiagnostic studies consistent with carpal tunnel syndrome. Follow-up evaluations were performed at twenty-one, forty-two, and eighty-four days. At the end of the follow-up period, both the open and endoscopic methods had resulted in high levels of achievement of the primary outcomes (relief of pain and paresthesias). The numbness and paresthesias were relieved in eighty (98 per cent) of eighty-two hands in the open-release group compared with seventy-seven (99 per cent) of seventy-eight hands in the endoscopic-release group. This parameter was not recorded for three hands in the open-release group or six hands in the endoscopic-release group. The satisfaction of the patients with the procedure, graded on a scale of 0 to 100 per cent, averaged 84 per cent in the open-release group compared with 89 per cent in the group that had had endoscopic release. We found no significant differences between the two groups with regard to the secondary quantitative-outcome measurements, including two-point discrimination, postoperative interstitial-pressure data for the carpal canal, Semmes-Weinstein monofilament testing, and motor strength. The open technique resulted in more tenderness of the scar than did the endoscopic method. Thirty-two (39 per cent) of eighty-two hands in the open-release group and fifty (64 per cent) of seventy-eight hands in the endoscopic-release group were not tender at eighty-four days. This parameter was not recorded for three hands in the open-release group and six hands in the endoscopic-release group. The open method also resulted in a longer interval until the patient could return to work (median, twenty-eight days, compared with fourteen days for the open-release and endoscopic-release groups). Four complications occurred in the endoscopic carpal-tunnel release group: one partial transection of the superficial palmar arch, one digital-nerve contusion, one ulnar-nerve neuropraxia, and one wound hematoma.(ABSTRACT TRUNCATED AT 400 WORDS)

Carpal tunnel release. A prospective, randomized assessment of open and endoscopic methods

To define the role of two-portal endoscopic carpal-tunnel release as a method for the treatment of compression of the median nerve at the wrist, a prospective, randomized, multicenter study was performed on 169 hands in 145 patients. Either open or endoscopic carpal-tunnel release was performed in all of the patients who had clinical signs and symptoms consistent with carpal tunnel syndrome, had not responded to or had refused non-operative management, and had had electrodiagnostic studies consistent with carpal tunnel syndrome. Follow-up evaluations were performed at twenty-one, forty-two, and eighty-four days. At the end of the follow-up period, both the open and endoscopic methods had resulted in high levels of achievement of the primary outcomes (relief of pain and paresthesias). The numbness and paresthesias were relieved in eighty (98 per cent) of eighty-two hands in the open-release group compared with seventy-seven (99 per cent) of seventy-eight hands in the endoscopic-release group. This parameter was not recorded for three hands in the open-release group or six hands in the endoscopic-release group. The satisfaction of the patients with the procedure, graded on a scale of 0 to 100 per cent, averaged 84 per cent in the open-release group compared with 89 per cent in the group that had had endoscopic release. We found no significant differences between the two groups with regard to the secondary quantitative-outcome measurements, including two-point discrimination, postoperative interstitial-pressure data for the carpal canal, Semmes-Weinstein monofilament testing, and motor strength. The open technique resulted in more tenderness of the scar than did the endoscopic method. Thirty-two (39 per cent) of eighty-two hands in the open-release group and fifty (64 per cent) of seventy-eight hands in the endoscopic-release group were not tender at eighty-four days. This parameter was not recorded for three hands in the open-release group and six hands in the endoscopic-release group. The open method also resulted in a longer interval until the patient could return to work (median, twenty-eight days, compared with fourteen days for the open-release and endoscopic-release groups). Four complications occurred in the endoscopic carpal-tunnel release group: one partial transection of the superficial palmar arch, one digital-nerve contusion, one ulnar-nerve neuropraxia, and one wound hematoma.(ABSTRACT TRUNCATED AT 400 WORDS)

Vascularity of the lunate. Anatomic studies and implications for the development of osteonecrosis

Osteonecrosis of the lunate is well established as the pathologic entity underlying the clinical condition known as Kienböck's disease. Consequently, the extraosseous and intraosseous blood supplies to the lunate have been well studied. A series of three palmar and three dorsal arterial arches provide a consistent volar supply to the lunate, and a frequent, but inconsistent, dorsal supply. Volar and dorsal foramina each generally contribute one to two vessels to a volar and dorsal intraosseous arterial network. The dorsal and volar arterial systems anastomose distal to the midline of the lunate; however, in as many as 7.5% of lunates, no anastomosis my be present. Between 7% and 26% of lunates may lack either a volar or dorsal arterial supply. These findings have significant implications regarding possible mechanisms for the development of osteonecrosis and the treatment of Kienböck's disease.

In vitro biomechanical analysis of suture methods for flexor tendon repair

This study was designed to compare five different suture methods that are used clinically for tendon repair. The flexor digitorum profundus tendons from the digits of adult mongrel dogs and adult human cadavers were used as models. The tendons in zone II of the hand, defined as the region from the distal palmar crease to the insertion of the flexor digitorum superficialis tendon at the middle phalanx, were transected and then were repaired by one of the suture methods developed by Kessler, Tsuge, Tajima, Savage, or Lee. The gliding function and tensile properties of the repaired tendons were evaluated biomechanically at time zero. The Tajima and Savage methods produced better gliding function than the other techniques. In the canine specimens that had been repaired by one of these two methods, the rotation of the distal interphalangeal joint was more than 60% of the rotation of the canine control specimens; only the Savage technique produced a rotation 124% that of the human control specimens. After the Tajima repair, the rotation of the proximal interphalangeal joint was 113% that of the canine control specimens and 157% that of the human controls. In the canine specimens that had had the Tajima or Savage repair, excursion of the tendon was greater than 55% that of the controls. The tendons repaired by the Savage method tolerated a significantly higher ultimate load to failure (14 and 25% that of the canine and human control specimens, respectively) than the other methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Injuries of the ulnar collateral ligament of the thumb metacarpophalangeal joint. Biomechanical and prospective clinical studies on the usefulness of valgus stress testing

In an effort to determine whether valgus stress testing of the thumb metacarpophalangeal joint is predictive of a torn and displaced ulnar collateral ligament, anatomic and prospective clinical studies were performed and the results correlated. In the anatomic study on autopsy specimens, dividing the proper collateral ligament resulted in a significant increase in valgus instability of the flexed metacarpophalangeal joint. Significantly less laxity was noted when the joint was tested in extension. When the accessory collateral ligament/palmar plate complex was also divided, valgus instability in extension increased to the extent that it no longer differed significantly from the values obtained when the joint was tested in 30 degrees flexion. In the clinical study, valgus instability of greater than 35 degrees when the joint was positioned in extension and then stressed consistently indicated the presence of tears of the proper and accessory collateral ligaments: A Stener's lesion was present in 15 of 17 such cases (87%). Values on valgus stress testing of the metacarpophalangeal joint in extension and 30 degrees flexion are highly predictive of both disruption and displacement of the ulnar collateral ligament of the thumb.

Autogenous flexor-tendon grafts. A biomechanical and morphological study in dogs

Intrasynovial and extrasynovial donor autogenous flexor-tendon grafts were placed in the synovial sheaths of the medial and lateral digits of the forepaw in twenty dogs (forty tendons). Postoperatively, the dogs were managed with early, controlled, passive mobilization. Histological and ultrastructural evaluations were carried out at ten days, three weeks, and six weeks, and biomechanical analyses were performed at three and six weeks. The intrasynovial and extrasynovial tendon grafts showed different healing processes histologically. The extrasynovial tendon grafts healed with early ingrowth of peripheral adhesions, which appeared to become larger and more dense over time. These grafts exhibited decreased cellularity and early neovascularization at ten days, and there was evidence of progressive revascularization and cellular repopulation at three and six weeks. In contrast, the intrasynovial tendon grafts demonstrated minimum adhesions, and both cellularity and collagen organization were normal at each time-interval. The intrasynovial grafts had significantly more angular rotation at the proximal interphalangeal joint at three and six weeks than did the extrasynovial grafts (p < 0.05).