Biomedical subjects

Kai-Nan An

Publications and source records attributed to Kai-Nan An.

At least 37 records · Page 2Linked to original sources

PubMed2006

Expression and mapping of lubricin in canine flexor tendon.

Matrix composition and the biomechanical environment are intimately interdependent in most connective tissues. Lubricin has many distinct biological functions, including lubrication, antiadhesion, and cytoprotection in cartilage, tendons, and other tissues. This study investigated the distribution of lubricin in the canine flexor digitorum profundus (FDP) tendon by immunohistochemistry. Lubricin was found both on the tendon surface and at the interface of collagen fiber bundles within the tendon, where the cells are subjected to shear force in addition to tension and compression. The expression of lubricin in regions of the canine flexor tendon that differ in mechanical or nutritional environment was also investigated using RT-PCR. Six N-terminal splicing variants were identified from six distinct anatomical regions of flexor tendon. The variants with larger sizes were noted in regions subjected to significant shear and compressive forces. Lubricin is ubiquitous in the FDP tendon, with variations in distribution and splicing that appear to correspond to discrete anatomic locations that differ by mechanical or nutritional environment.

Animals↗

PubMed2006

High-resolution ultrasound analysis of subsynovial connective tissue in human cadaver carpal tunnel.

The carpal tunnel contains the median nerve, nine flexor tendons, two synovial bursae, and peritendinous subsynovial connective tissue (SSCT). Fibrosis of the SSCT is the most consistent pathological finding in patients with carpal tunnel syndrome. We investigated the anatomy and gliding characteristics of the flexor digitorum superficialis tendon and its adjacent SSCT with high-resolution ultrasound (15 MHz). Our hypotheses were that tendon and SSCT are distinguishable by ultrasound and that their velocities during tendon excursion are different. Qualitative ultrasound analysis of a flexor tendon and its SSCT was performed on five cadaver wrists and correlated to respective findings after anatomical study of the same cadavers. Quantitative Doppler velocity analysis of eight cadaver wrists was done to assess the sliding movement of the tendon and its SSCT within the carpal tunnel. No significant difference was found between the thickness of SSCT measured by ultrasound and that measured directly after dissection. The SSCT moved slower than its flexor tendon. The SSCT velocities were statistically different from the tendon velocities (t-test, p>0.001). High-resolution ultrasound is a very precise method to display the anatomy of the tendon and SSCT within the carpal tunnel, and their different velocities can be detected with Doppler. Noninvasive assessment of the thickness and velocity of the tenosynovium in carpal tunnel syndrome by high-resolution sonography might be a new diagnostic tool for disorders affecting the SSCT, especially carpal tunnel syndrome.

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PubMed2006

The effect of visual biofeedback on the propulsion effectiveness of experienced wheelchair users.

OBJECTIVE: To determine the effect of visual feedback on the propulsion effectiveness of experienced manual wheelchair users. DESIGN: Controlled trial. SETTING: A motion analysis laboratory. PARTICIPANTS: A convenience sample of 16 healthy men and 2 healthy women with T4-L2 traumatic paraplegia, a mean age of 38+/-9 years, and a mean duration of manual wheelchair-based mobility of 14+/-8 years. INTERVENTION: Propulsion was assessed as the subjects propelled an instrumented wheelchair (with and without visual biofeedback) on a custom-built dynamometer at propulsion intensities of .15 and .25W/kg for 10 minutes. MAIN OUTCOME MEASURES: The primary outcome variable was the fraction of effective force (FEF) (ie, the ratio of effective to total force) applied by the subject to the wheelchair's pushrim. Secondary variables included velocity, stroke frequency, and stroke angle. RESULTS: A 2-factor analysis of variance with repeated measurements was used to detect significant differences between the outcome variables. The FEF ratio was 73.9% without feedback and 72.5% with feedback at the lower-intensity level. Propulsion during the higher intensity condition both with and without feedback resulted in a statistically significant improvement in the FEF (73.9%-78.7% with no feedback, 72.5%-80.2% with feedback), compared with the lower-intensity level. Stroke angle increased from 84.3 degrees to 98.7 degrees and frequency decreased from 66 to 57.8 strokes/min with feedback. CONCLUSIONS: Visual biofeedback may have little utility in improving the force effectiveness of manual wheelchair propulsion in experienced wheelchair users. Experienced wheelchair users may have already optimized their stroke in a manner that balances energy expenditure with stroke efficiency. Other variables such as stroke length and frequency may be more amenable to visual biofeedback.

Adult↗

PubMed2006

Rotator cuff repair using an acellular dermal matrix graft: an in vivo study in a canine model.

PURPOSE: Large rotator cuff tears present a challenge to orthopaedic surgeons. Because tissue may be insufficient or of inadequate quality to undergo repair, a variety of materials have been used as adjuncts. Human dermal tissue may be processed to render it acellular, and thus less immunogenic, but with the extracellular matrix left intact, creating a collagen scaffold with favorable characteristics. Because of these traits, use in rotator cuff repair was proposed. METHODS: A canine model for a full-thickness infraspinatus tendon tear was used. Tendon was excised from the bony interface to the myotendinous junction, and a human acellular dermal matrix graft (experimental) or the autologous excised tendon (control) was used to bridge the defect. Animals were sacrificed, and shoulders were evaluated histologically and biomechanically. RESULTS: At time 0, strength of control and experimental repairs was similar. At 6 weeks, the strength of the experimental repair was half that of the control side. Strength of control specimens remained the same at 6 and 12 weeks, but by 12 weeks, the strength of the experimental repair was equal to that of the control. Histologically, cells infiltrated the control and experimental specimens by 6 weeks; chronic inflammation was consistent with surgery and repair. At 6 months, control and experimental specimens mimicked normal tendon structure grossly and histologically. CONCLUSIONS: Use of human acellular dermal matrix as a patch is a viable option in this model of large rotator cuff defects. Within 6 weeks, histologic evidence of native cell infiltration and neotendon development was observed. Within 12 weeks, the strength of the dermal matrix graft repair was equivalent to that of autologous tendon. At 6 months, control and graft specimens mimicked normal tendon structure grossly and histologically. CLINICAL RELEVANCE: This study provides in vivo animal data to support the use of this acellular dermal matrix graft for repair of full-thickness rotator cuff defects. Additional studies are indicated to determine the role of this material in the treatment of humans with rotator cuff tears.

Animals↗

PubMed2006

Using support vector machines to optimally classify rotator cuff strength data and quantify post-operative strength in rotator cuff tear patients.

Shoulder strength data are important for post-operative assessment of shoulder function and have been used in diagnosis of rotator cuff pathology. Support vector machines (SVM) employ complex analysis techniques to solve classification and regression problems. A SVM, a machine learning technique, can be used for analysis and classification of shoulder strength data. The goals of this study were to determine the diagnostic competency of SVM based on shoulder strength data and to apply SVM analysis in efforts to derive a single representative shoulder strength score. Data were taken from fourteen isometric shoulder strength measurements of each shoulder (involved and uninvolved) in 45 rotator cuff tear patients. SVM diagnostic proficiency was found to be comparable to reported ultrasound values. Improvement of shoulder function was accurately represented by a single score in pairwise comparison of the pre-operative and the 12 month post-operative group (P < 0.004). Thus, the SVM-based score may be a promising metric for summarizing rotator cuff strength data.

Artificial Intelligence↗

PubMed2006

Effect of finger ulnar deviation on gliding resistance of the flexor digitorum profundus tendon within the A1 and A2 pulley complex.

PURPOSE: To evaluate the effect of ulnar deviation of the finger on gliding resistance of the flexor digitorum profundus tendon within the A1 and A2 pulley complex. METHODS: Thirty-two human cadaveric fingers (index through small fingers) were used. The gliding resistance was measured at 5 different angles of ulnar deviation (0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees). RESULTS: There was a significant increase in gliding resistance with increased ulnar deviation. The gliding resistances at 0 degrees, 15 degrees, 30 degrees, 45 degrees, and 60 degrees of ulnar deviation were 0.40+/-0.13 N, 0.44+/-0.13 N, 0.55+/-0.17 N, 0.74+/-0.21 N, and 1.02+/-0.30 N, respectively. The gliding resistance at 60 degrees was significantly greater than at all other angles; 45 degrees ulnar deviation had significantly higher gliding resistance than 0 degrees, 15 degrees, and 30 degrees; and 30 degrees ulnar deviation had significantly higher gliding resistance than 0 degrees. CONCLUSIONS: A greater angle of ulnar deviation causes higher gliding resistance during motion of the flexor digitorum profundus tendon within the A1 and A2 pulley complex. The gliding resistance increases significantly at angles greater than 30 degrees of ulnar deviation. The increased tendon loading needed to overcome increased gliding resistance caused by ulnar deviation could result in a vicious cycle of progressive ulnar deviation. Although mild degrees of ulnar deviation may be well tolerated mechanically a reasonable therapeutic guideline might be to prevent deviation from exceeding 30 degrees.

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PubMed2006

Relative contributions of the ulnar attachments of the triangular fibrocartilage complex to the dynamic stability of the distal radioulnar joint.

PURPOSE: Laboratory studies evaluating the importance of the stabilizing structures of the distal radioulnar joint (DRUJ) largely have been limited to static design. Clinically, dynamic loading seems to be an important component of DRUJ instability. This study was designed to evaluate the influence of dynamic loading on the stability of the DRUJ with foveal versus styloid triangular fibrocartilage complex (TFCC) disruptions in a laboratory setting. METHODS: Twelve fresh-frozen cadaveric upper-extremity specimens were tested using a dynamic simulator to study the contributions of the 2 ulnar insertions of the TFCC to the dynamic stability of the DRUJ. The specimens were tested in 3 loading conditions (no load, agonist loading, antagonist loading) in 3 different states of the TFCC (intact, foveal disruption, styloid disruption). RESULTS: Without load no significant differences were found for the different conditions of the TFCC. Under loaded conditions the foveal insertion had a greater effect on stability than did the styloid insertion. Under agonist loading significant differences were found during supinating and pronating motions. With antagonist loading a significant difference was found only during supination. CONCLUSIONS: The study results support the clinical impression that dynamic loading is an important component of DRUJ instability and that disruption of the foveal TFCC insertion into the foveal region of the distal ulna can produce instability.

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PubMed2006

The wettability of intrasynovial and extrasynovial tendons.

PURPOSE: The surface properties of biologic materials are important to their observed physiochemical responses, mechanical interactions, and compatibility with other materials. The purpose of this study was to characterize further the surface properties of canine tendons, specifically how they interface with fluids--that is, their wettability. METHODS: Drop-shape analysis was used to study contact angles on intrasynovial and extrasynovial tendon surfaces. This standard goniometric method was used to estimate tendon-wettability properties. RESULTS: This study showed that extrasynovial tendon portions (particularly the dorsal sides) are more wettable than intrasynovial tendons. We also showed that trypsin digestion of tendon surfaces increases their wettability. CONCLUSIONS: The wettability differences between intrasynovial and extrasynovial canine tendons may help to explain known differences in the propensities of these 2 different tendon types to form adhesions after surgery.

Absorption↗

PubMed2006

Mapping lubricin in canine musculoskeletal tissues.

Lubricin, also known as superficial zone protein or PRG4, has many distinct biological functions, including lubrication, antiadhesion, and as a regulator of cell growth. This study investigated lubricin in canine musculoskeletal tissues using RT-PCR and immunohistochemistry. One or more variants were noted in canine flexor digitorum profundus (FDP) tendon, Achilles tendon, patellar tendon, A2 pulley, anterior cruciate ligament (ACL), knee lateral collateral ligament (LCL), articular cartilage, meniscus, muscle, and skin. We found 6 N-terminal lubricin splicing variants. The variants with larger sizes were identified in FDP tendon, ACL, LCL, A2 pulley, and cartilage. Lubricin was distributed both on the tissue surfaces and at the interface of fiber bundles within tissues, but this distribution varied by tissue type. We conclude that lubricin is present in many tissues; variations in splicing and physical distribution suggest that the variants of lubricin may play different roles in different locations.

Alternative Splicing↗

PubMed2006

Changes in the functional structure of the tenosynovium in idiopathic carpal tunnel syndrome: a scanning electron microscope study.

BACKGROUND: The subsynovial connective tissue lies between the flexor tendons and visceral synovium in the carpal tunnel. Although tenosynovial fibrosis is nearly universally noted in patients with carpal tunnel syndrome, the relationship, if any, between the fibrosis and nerve abnormalities is unknown. The authors used light and scanning electron microscope imaging of the subsynovial connective tissue to gather information about its organization. METHODS: Human subsynovial connective tissue was studied to determine its ultrastructural morphology. Biopsy specimens of 11 patients (12 hands) with idiopathic carpal tunnel syndrome, 14 cadaver controls, and two cadavers with a history of carpal tunnel syndrome were obtained for scanning electron microscopic imaging and histopathologic examination. RESULTS: The visceral synovial layer is an uninterrupted membrane that defines the bursa dorsally. The subsynovial connective tissue consists of fibrous bundles that run parallel to the tendon, interconnected by smaller fibrous fibers. It connects to the synovial membrane and the flexor tendons. During tendon motion, the loose fibers between adjacent layers are stretched. The control tissue showed interconnections between all the parallel layers, whereas in patients with idiopathic carpal tunnel syndrome, these interconnections were absent, replaced with thicker parallel fibrous bundles. Similar changes were found in the cadaver carpal tunnel syndrome specimens. Pathologic changes in the patient and cadaver carpal tunnel syndrome specimens were most apparent close to the tendon and became progressively less severe in more superficial layers. CONCLUSIONS: The authors' observation that the most severe changes in the subsynovial connective tissue were found close to the tendon suggests that these changes may be the result of a shearing injury.

Adult↗

PubMed2006

Gliding resistance of the flexor pollicis longus tendon after repair: does partial excision of the oblique pulley affect gliding resistance?

BACKGROUND: After tendon repair, it is critical for the repair site to pass smoothly under the pulley edge to promote gliding and reduce the risk of adhesion or rupture. In this study, the authors assessed the effect of partial excision by "squaring off" the distal edge of the oblique pulley on the gliding resistance of the flexor pollicis longus tendon after repair in vitro. METHODS: Gliding resistance of 10 human thumbs was measured directly with three different sequential conditions: intact flexor pollicis longus tendon with intact A1 and oblique pulleys (group A), intact pulleys after repair of the tendon (group B), and after repair and excision of the distal triangular part (squaring off) of the oblique pulley (group C). RESULTS: Gliding resistance increased significantly after repair and squaring off the oblique pulley (group A, 0.22 +/- 0.08 N; group B, 1.29 +/- 0.68 N; and group C, 2.01 +/- 0.84 N). CONCLUSIONS: Previous studies suggest that the trimming of an annular pulley in the finger would not result in any significant mechanical disadvantage if other parts of the pulley system were intact. However, the authors' results suggest that in the case of the thumb oblique pulley, gliding resistance is increased after trimming and tendon repair, and thus the oblique pulley should be left intact if possible.

Aged↗

PubMed2006

Biomechanical efficiency of wrist guards as a shock isolator.

Despite the use of wrist guards during skate- and snowboard activities, fractures still occur at the wrist or at further proximal locations of the forearm. The main objectives of this study were to conduct a human subject testing under simulated falling conditions for measurement of the impact force on the hand, to model wrist guards as a shock isolator, to construct a linear mass-spring-damper model for quantification of the impact force attenuation (Q-ratio) and energy absorption (S-ratio), and to determine whether wrist guards play a role of an efficient shock isolator. While the falling direction (forward and backward) significantly influenced the impact responses, use of wrist guards provided minimal improvements in the Q- and S-ratios. It was suggested based on the results under the submaximal loading conditions that protective functions of the common wrist guard design could be enhanced with substantial increase in the damping ratio so as to maximize the energy absorption. This would bring forth minor deterioration in the impact force attenuation but significant increase in the energy absorption by 19%, which would help better protection against fall-related injuries of the upper extremity.

Adult↗

PubMed2006

Consequences of partial and total plantar fascia release: a finite element study.

BACKGROUND: Plantar fasciotomy, a common operative procedure to relieve chronic heel pain, has been suggested to decrease foot arch stability. A systematic evaluation of the biomechanical consequences of partial or total plantar fascia release is essential to the understanding of the biomechanical rationale behind these operative procedures. METHODS: A geometrical detailed three-dimensional (3-D) finite element (FE) model of the human foot and ankle, incorporating geometrical and contact nonlinearities, was constructed by 3-D reconstruction of MR images. Partial and complete plantar fascia releases were simulated to evaluate the corresponding biomechanical effects on load distribution of the bony, ligamentous, and encapsulated soft-tissue structures. RESULTS: Partial and total plantar fascia release may decrease arch height but did not necessarily cause total collapse of the foot arch even with additional dissection of the long plantar ligament. Operative release of the plantar fascia was compromised by increased strains of the plantar ligaments and intensified stress in the midfoot and metatarsal bones. Load redistribution among the centralized metatarsal bones and focal stress relief at the calcaneal insertion were predicted with different types of fasciotomy. CONCLUSIONS: The FE model suggested that plantar fascia release may provide relief of focal stress and therefore could relieve associated heel pain. However, these operative procedures may pose a risk to arch stability and clinically may produce dorsolateral midfoot pain. The initial strategy for treating plantar fasciitis should be nonoperative. If surgery is necessary, partial release of less than 40% of the fascia is recommended to minimize the effect on arch instability and maintain normal foot biomechanics.

Adult↗

PubMed2006

Gliding resistance of the posterior tibial tendon.

BACKGROUND: Abnormal gliding of the posterior tibial tendon may lead to mechanical trauma, degeneration, and eventually posterior tibial tendon dysfunction. Our study analyzed the gliding resistance of the posterior tibial tendon in intact feet and in feet with simulated flatfoot deformity. METHODS: An experimental system was developed that allowed direct measurement of gliding resistance at the tendon-sheath interface. Seven normal fresh-frozen cadaver foot specimens were studied, and gliding resistance between the posterior tibial tendon and sheath was measured. The effects of ankle and hindfoot position and the effect of flatfoot deformity on gliding resistance were analyzed. Gliding resistance was measured for 4.9 N applied load to the tendon. RESULTS: Mean gliding resistance for the neutral position was 77 +/- 13.1 (x10(-2) N). Compared to neutral position, dorsiflexion increased gliding resistance and averaged 130 +/- 38.9 (x10(-2) N), and plantarflexion decreased gliding resistance and averaged 35 +/- 12.6 (x10(-2) N). Flatfoot deformity increased gliding resistance compared to normal feet, averaging 104 +/- 17.0 (x10(-2) N) for neutral, 205 +/- 55.0 (x10(-2) N) for dorsiflexion, and 58 +/- 21.3 (x10(-2) N) for plantarflexion. CONCLUSIONS: The findings indicate that patients with a preexisting flatfoot deformity may be predisposed to develop posterior tibial tendon dysfunction because of increased gliding resistance and trauma to the tendon surface.

Aged↗

PubMed2006

Ankle ligament tensile forces at the end points of passive circumferential rotating motion of the ankle and subtalar joint complex.

BACKGROUND: Ankle ligament injuries and instability are commonly observed. Knowledge of the relationship between the foot position and tensile forces of the ankle ligaments could be useful for treatment of ankle ligament disorders. The aim of this study was to measure the tensile forces of the ankle ligaments at the end points of passive circumferential rotating motion of the ankle and subtalar joint complex in various foot positions. METHODS: Ligament tensile forces of the anterior talofibular (ATF), calcaneofibular (CF), posterior talofibular (PTF), and tibiocalcaneal (TC) ligaments were measured simultaneously in eight cadaver specimens, with a force probe in each ligament in a custom-made ankle ligament testing device. Weights of 0.5 kg and 1 kg were applied to the foot through a loading arm to provide axial compression and a bending moment to the foot and ankle. The position of the loading arm was changed circumferentially in 10-degree increments. RESULTS: Maximal tensile force in the ATF ligament was observed in supination with plantarflexion (108 +/- 62.8 N at 0.5 kg and 130 +/- 39.1 N at 1 kg). The maximal tensile force in the CF ligament was observed in pronation with plantarflexion (68 +/- 48.6 N at 0.5 kg and 135 +/- 92.9 N at 1 kg). The maximal tensile force in the PTF ligament was observed in dorsiflexion (131 +/- 80.1 N at 0.5 kg and 109 +/- 36.3 N at 1 kg). The maximal tensile force of the TC ligament was observed in pronation with plantarflexion (49.0 +/- 80.1 N at 0.5 kg and 67.4 +/- 69.6 N at 1 kg). Relatively high magnitudes of tensile force were observed in the ankle ligaments, and the peak forces were related to the anatomic position of individual ligaments. CONCLUSIONS: The ATF ligament has an important role in the supination position in plantarflexion, CF and TC ligaments also are important for pronation in plantarflexion, and the PTF is an important stabilizer in dorsiflexion. This study provides baseline information for further research related to ligament instability and reconstruction operations.

Aged↗

PubMed2006

Comparison of modified Broström and Evans procedures in simulated lateral ankle injury.

PURPOSE: The purpose of this study was to compare the modified Broström and Evans procedures for simulated lateral ankle instability in cadaveric lower extremities. METHODS: Six normal cadaveric ankles were loaded with inversion and internal rotation stress through the range of ankle flexion, and three-dimensional motion of the calcaneus and talus relative to the tibia were measured. An ankle stability testing device and a magnetic tracking system were used. Testing was performed in the intact condition, unstable condition after sectioning both the anterior talofibular (ATFL) and calcaneofibular ligaments (CFL), after the Gould modification of the Broström procedure, and after the Evans procedure. RESULTS: With inversion loading, both operations resulted in a significantly more stable ankle-hindfoot complex (calcaneal-tibial) than the unstable condition, but there was restricted motion after the Evans operation from neutral to plantarflexion. Tibiotalar inversion motion approximated normal after both operations, but subtalar motion was markedly restricted in the Evans procedure throughout the range of ankle flexion. With internal rotation loading, the Broström operation stabilized the ankle-hindfoot joint complex in plantarflexion. The Evans operation improved internal rotation stability, but restricted motion in all positions. Both operations improved tibiotalar internal rotation stability, but not to normal. The subtalar internal rotation was the same as the intact condition after the Broström operation, but markedly restricted after the Evans operation through the range of ankle flexion. CONCLUSIONS: Both operations improved ankle-hindfoot stability, but neither was successful in restoring it to normal as determined with the ankle stability testing device. The Evans procedure improved stability at the expense of creating abnormal subtalar function. The Broström operation improved stability without excessively restricting subtalar movement, but was not effective in addressing the internal rotation laxity.

Aged↗

PubMed2006

Morphological changes of collagen fibrils in the subsynovial connective tissue in carpal tunnel syndrome.

BACKGROUND: Pathologic changes occur commonly in the subsynovial connective tissue in patients with carpal tunnel syndrome. The purposes of this study were to investigate the ultrastructural changes of the subsynovial connective tissue in these patients and compare them with the findings in cadaver controls. METHODS: The diameter and density of collagen fibrils were measured by transmission electron microscopy in specimens of subsynovial connective tissue from ten patients with idiopathic carpal tunnel syndrome and from ten fresh-frozen cadavers of individuals without known symptoms of carpal tunnel syndrome. RESULTS: We noted deformed collagen fibrils with a spiraled appearance in the specimens from the patients. We also observed phagocytosis of elastin fibrils in all of those specimens. These changes were noted only rarely in the cadaver controls. The mean diameter (and standard deviation) of the collagen fibrils was 45.5 +/- 8.0 nm in the control group and 54.8 +/- 15.2 nm in the patient group (p < 0.05). The mean number of collagen fibrils per 0.04 microm2 (density) was 201.38 +/- 48.88 in the control group and 157.08 +/- 54.38 in the patient group (p < 0.05). CONCLUSIONS: These ultrastructural findings suggest that subsynovial collagen in patients with carpal tunnel syndrome is structurally different from that in individuals without carpal tunnel syndrome, but the processes resulting in that abnormal morphology remain to be elucidated.

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PubMed2006

Surface treatment of flexor tendon autografts with carbodiimide-derivatized hyaluronic Acid. An in vivo canine model.

BACKGROUND: Clinical and experimental studies have demonstrated that restrictive adhesions and poor digital motion are common complications after extrasynovial tendon grafting in an intrasynovial environment. The purpose of this study was to test the hypothesis that surface modification of an extrasynovial tendon with use of a carbodiimide-derivatized hyaluronic acid-gelatin polymer (cd-HA) improves gliding ability and digital function after tendon grafting in a canine model in vivo. METHODS: The peroneus longus tendons from both hindpaws of twenty-four dogs were harvested and transplanted to replace the flexor digitorum profundus tendons in the second and fifth digits of one forepaw. Prior to grafting, one of the peroneus longus tendons was coated with cd-HA, which consists of 1% hyaluronic acid, 10% gelatin, 0.25% 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), and 0.25% N-hydroxysuccinimide (NHS), while the other was immersed in saline solution only. Eight dogs were killed at one, three, and six weeks. Digital normalized work of flexion, tendon gliding resistance, and hyaluronic acid quantification (with the hyaluronic acid-binding-protein staining technique) were the outcome measures. RESULTS: The normalized work of flexion of the tendons treated with cd-HA was significantly lower than that of the saline-solution-treated controls at each time-point (p < 0.05). The gliding resistance of the cd-HA group was significantly lower than that of the saline-solution group at three and six weeks (p < 0.05). The ratio between the intensity of staining of the cd-HA-treated tendons with that of the saline-solution-treated controls was significantly greater at time-0 than at three or six weeks (p < 0.05), but there was no significant difference between time-0 and one-week values. CONCLUSIONS: Treating the surface of an extrasynovial tendon autograft with a carbodiimide-derivatized hyaluronic acid-gelatin polymer decreases digital work of flexion and tendon gliding resistance in this flexor tendon graft model in vivo. CLINICAL RELEVANCE: cd-HA gelatin may provide surgeons with a new and useful method to improve the quality of tendon graft surgery.

Animals↗