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Biomedical subjects

Peter C Amadio

Publications and source records attributed to Peter C Amadio.

At least 19 recordsLinked to original sources
PubMed2006

Effect of wrist and ulna head position on gliding resistance of the extensor digitorum minimi and extensor digitorum communis III tendons: a cadaver study.

While attrition from sharp bony surfaces is the most common cause of extensor digiti minimi (EDM) tendon rupture, the etiology of other cases of spontaneous EDM tendon rupture is still unknown. Friction within the compartment may play a role, especially with ulna dislocation. The purpose of this study was to compare gliding resistance of the EDM tendon with that of a tendon which rarely ruptures spontaneously, the extensor digitorum communis of the middle finger (EDC III) tendon, under various wrist and ulna head positions. Eight fresh frozen cadavers were used. Gliding resistance between the tendon and its sheath in each compartment was measured in five different wrist positions and three different ulna head positions. Gliding resistance of the EDM tendon (0.13 +/- 0.03 N) was significantly greater than the EDC III tendon (0.09 +/- 0.03 N) (p < 0.05). For the EDM tendon, the gliding resistance in ulnar deviation or pronation was higher than the gliding resistance in neutral, radial deviation, or supination (p < 0.05), and the gliding resistance with ulnar lengthening (over 6 mm) or dorsal ulnar dislocation (over 9 mm) was higher than in neutral ulnar head positioning. For the EDC III tendon, the gliding resistance in ulnar deviation was significantly higher than the gliding resistance in neutral, radial deviation, or supination, or dorsal dislocation with ulnar lengthening (p < 0.05). Wrist ulnar deviation, ulnar dorsal dislocation (over 9 mm), and ulnar lengthening (over 6 mm) increased the gliding resistance of the EDM tendon. In patients at risk for EDM rupture, such as those with rheumatoid arthritis or distal radioulnar joint osteoarthritis, avoiding such positions may be advantageous.

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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

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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PubMed2005

Finkelstein's test: a biomechanical analysis.

PURPOSE: Finkelstein's test is the classic diagnostic test for de Quervain's disease. Finkelstein hypothesized that the entry of the muscle bellies of the extensor pollicis brevis (EPB) and abductor pollicis longus (APL) tendons into the first extensor compartment was responsible for the findings observed in his now eponymous test. We agree with Finkelstein's hypothesis and further hypothesize that this position would induce measurable bulk (muscle mass within the retinaculum) and tethering (stretching of synovial tissue) effects within the compartment. To test this latter hypothesis we measured the excursion and gliding resistance of the EPB and APL tendons within the first compartment. METHODS: Fifteen fresh-frozen cadavers were used. Gliding resistance and excursion were measured in 4 different wrist positions, including the wrist position of Finkelstein's test (30 degrees ulnar deviation). The bulk and tethering effect was calculated based on the mean gliding resistance over the tendon proximal/distal excursion cycle and the gliding resistance at the terminal distal excursion. RESULTS: The EPB tendon excursion was significantly more distal in 30 degrees ulnar deviation than in 60 degrees extension. Additionally the bulk and tethering resistance was significantly greater in 30 degrees ulnar deviation compared with 60 degrees extension. For the APL tendon there was no significant difference in either the tendon excursion or the bulk and tethering resistance between 30 degrees ulnar deviation and 60 degrees extension. CONCLUSIONS: We showed that in the position of Finkelstein's test the EPB tendon is significantly more distal and has significantly greater bulk and tethering effect compared with the other EPB positions. This is not the case for the APL tendon in the position of Finkelstein's test. These results suggest that an abnormal Finkelstein's test reflects differences of the EPB more than it does the APL.

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PubMed2005

Total and intrasynovial work of flexion of human cadaver flexor digitorum profundus tendons after modified Kessler and MGH repair techniques.

PURPOSE: The purpose of this study was to compare directly the total work of flexion (TWOF) and the intrasynovial work of flexion (IWOF) of human flexor digitorum profundus tendons and to analyze the ratio of the IWOF to the TWOF of human flexor digitorum profundus tendons. These factors may be important clinically in understanding the role of different methods of postoperative tendon rehabilitation for different types of tendon repairs, especially at the early stage after tendon repair. METHODS: Two different tendon repairs, the modified Kessler and the Massachusetts General Hospital, were used in 18 digits from 6 freshly frozen human cadaver hands. The TWOF and the IWOF were tested by using a digit-resistance testing device. RESULTS: After tendon repair the TWOF increased 11.2% and 26.9% for the modified Kessler and MGH groups, respectively. The differences in increase between the 2 groups were significant. The IWOF increased 126.8% and 308.8% for the modified Kessler and Massachusetts General Hospital groups, respectively. The IWOF accounted for 16.4% of the TWOF for the intact tendon; this percentage was 28.6% and 45.0% for the modified Kessler and Massachusetts General Hospital groups, respectively. CONCLUSIONS: The IWOF accounts for 16% of the TWOF of normal human cadaver digits but it accounts for a much higher fraction after tendon repair. The ratio of the work of flexion within the synovial sheath to the TWOF varies depending on the type of repair chosen.

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PubMed2005

Gliding resistance of the extensor pollicis brevis tendon and abductor pollicis longus tendon within the first dorsal compartment in fixed wrist positions.

PURPOSE: While the etiology of de Quervain's disease is unknown, repetitive motion coupled with awkward wrist position and septation within the first dorsal compartment are considered causative factors. We hypothesize that these conditions might produce high gliding resistance, which could then induce micro-damage of the tendons and retinaculum. The purpose of this study was to measure the gliding resistance of the extensor pollicis brevis and abductor pollicis longus tendons within the first dorsal compartment in a human cadaver model. METHODS: Fifteen human cadaver wrists, which included eight septation and seven non-septation wrists in the first dorsal compartment, were used. Gliding resistance of the extensor pollicis brevis and abductor pollicis longus tendons was measured in seven wrist positions: 60 degrees extension, 30 degrees extension, 0 degrees, 30 degrees flexion, 60 degrees flexion in neutral deviation and 30 degrees ulnar deviation, 15 degrees radial deviation in neutral extension/flexion. RESULTS: The overall gliding resistance was not different between septation and non-septation wrists (0.21 versus 0.19 N for abductor pollicis longus and 0.21 versus 0.15 N for extensor pollicis brevis, respectively), but there was a significant effect on gliding resistance due to wrist position (p<0.05) in both tendons. Interaction between wrist position and septation status was observed in the extensor pollicis brevis tendon (p<0.05). With septation, the gliding resistance of the extensor pollicis brevis was significantly higher in 60 degrees wrist flexion (0.51 N) compared to all other wrist positions tested (all less than 0.26 N) (p<0.05). In the non-septation group, gliding resistance was significantly higher in 60 degrees flexion (0.20 N) and 60 degrees extension (0.22 N) compared to the other five wrist positions (all less than 0.15 N) (p<0.05). Although no significant difference was observed, the extensor pollicis brevis tendon with septation tended to have higher gliding resistance than that without septation in wrist flexion. In 60 degrees of wrist flexion the abductor pollicis longus tendon had significantly higher gliding resistance (0.33 N) than the other wrist positions (all less than 0.26 N) (p<0.05). CONCLUSIONS: A combination of septation and wrist position significantly affected extensor pollicis brevis tendon gliding resistance in this cadaver model. These factors may contribute to the development of de Quervain's disease.

Biomechanical Phenomena↗
PubMed2005

Effect of elbow position on canine flexor digitorum profundus tendon tension.

Tendon injury in the finger remains a clinical challenge to hand surgeons. A canine model is commonly used to study biological effects of tendon injuries and their treatment. There is an important anatomical difference between human and canine anatomy that may be overlooked, however, namely that most of the flexor digitorum profundus (FDP) muscle in dogs takes its origin from the medial epicondyle of the humerus, whereas in humans this muscle arises purely from the forearm. Therefore, elbow position can affect the tension of this muscle in dogs, while having no effect in humans. The purpose of this study was to measure the effect of elbow position on tendon tension in the canine digit in vitro. Elbow position had a significant effect on tendon tension. Digit motion with the elbow fully flexed resulted in significantly higher tendon tension compared to digit motion with the elbow flexed 90 degrees or fully extended, regardless of digit or wrist position (p<0.05). The tension with the elbow flexed 90 degrees was also significantly higher than with the elbow fully extended (p<0.05). The maximum tendon tension with the elbow fully flexed was more than eight times larger than that of the fully extended elbow (p<0.05). We conclude that, in the canine model, elbow position is an important parameter that affects the passive tension applied to the flexor digitorum profundus, and, by implication, to any repair of that tendon. Dog flexor tendon rehabilitation protocols should therefore specify elbow position, in addition to wrist and digit position.

Animals↗
PubMed2005

Immunolocalization of collagen types in the subsynovial connective tissue within the carpal tunnel in humans.

The tenosynovium within the carpal tunnel consists of a single layer of synovial cells, which lines the bursae within the carpal tunnel, and the subsynovial connective tissue (SSCT), which contains the tendon vasculature and other structural elements. In this study, we used immunogold labeling to localize collagen types within the SSCT in three cadaver specimens and three patients with carpal tunnel syndrome. Positive labeling for collagen types I, III and VI was found with immunoelectron microscopy. Collagen types I and III were codistributed within the SSCT. Type VI was primarily located in microfibrillar structures between collagen bundles, between elastin and collagen bundles and between collagen bundles and cells. There was no difference in the distribution of collagen types when comparing cadaver specimens and carpal tunnel patients.

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PubMed2005

Epithelioid sarcoma of the hand.

Twenty-eight patients were treated for a primary epithelioid sarcoma of the hand. Twenty-seven patients (96%) had excisions before evaluation, including 11 (39%) with multiple prior excisions with varying diagnoses before epithelioid sarcoma, and all had surgical treatment after referral. The patients' surgical management included three patients with amputation at the forearm, three patients with wide excision, and 21 patients with a partial amputation of the hand. The followup period averaged 120 months (range, 24-276 months). Eighteen patients have no evidence of disease at last followup. Treatment failures included one local recurrence, four regional metastases, and five distant metastases. Five patients died secondary to disease. Two patients are alive with disease, and three are alive with no evidence of disease after additional treatment. After aggressive surgical management with negative margins, 71% of the patients were alive without evidence of disease at the last followup, with a 5- and 10-year survivorship of 85%. Our goal is to review: (1) the effectiveness of preoperative imaging, (2) the role of adjuvant therapy, (3) survival after alternative resections, and (4) function after resection.

Adult↗
PubMed2004

A prospective clinical practice intervention to improve osteoporosis management following distal forearm fracture.

Secondary prevention of osteoporosis after fracture is underutilized, despite cost-effective therapies. This clinical practice intervention aimed to improve osteoporosis care of the postfracture patient. Residents of Olmsted County, Minnesota, USA, > or = age 45 who sustained a moderate trauma distal forearm fracture were identified, and participants received educational materials, referral for bone densitometry and physician consultation to address osteoporosis in January 1999 through October 2000. Osteoporosis educational materials were provided to patients at the time of recruitment, and primary care physicians provided osteoporosis practice guidelines. Outcomes included: completion of bone densitometry, acceptance of interventions at the first postfracture primary care physician visit, and adherence to advice at 6 months. There were 105 patients identified (80% women), but only 58 agreed to participate (88% women). Women with lower T-scores (< -1.5) had an 89% initial treatment rate, and 67% were adherent to treatment at 6 months. All women with normal bone density (T-score above -1.5) were advised by their primary care physicians about antiresorptive treatment, and 100% adhered to these recommendations, even though they were not eligible for such treatment based on the National Osteoporosis Foundation (NOF) guidelines. None of the men accepted the treatments offered, despite T-scores that fell at or below the NOF treatment threshold. Bone densitometry and consultation improved osteoporosis interventions after index fracture from a 16% baseline rate in the population (1993-1997) to a 45% overall rate for the study population. In summary, while referral for bone densitometry and discussion by a physician about postfracture osteoporosis preventive treatments did increase treatment rate, the majority of patients at highest risk did not accept interventions. Further initiatives are needed to overcome both system and patient barriers.

Absorptiometry, Photon↗
PubMed2004

Tendon surface modification by chemically modified HA coating after flexor digitorum profundus tendon repair.

Carbodiimide derivatized HA (cd-HA) is less soluble in water than normal HA, and therefore has an increased tissue residence time. The purpose of this study was to study the effect of cd-HA gel on gliding and repair integrity during simulated repetitive motion of a repaired tendon in vitro. A total of 36 flexor digitorum profundus (FDP) tendons from six adult mongrel dogs were used and divided into three groups of control, simple HA, and cd-HA. The gliding resistance between the FDP and the proximal pulley, FDS, and bone was measured before laceration and after modified Kessler technique repair at 1, 5, 10, 50, 100, 200, 300, 400, and 500 cycles. After gliding testing, failure load, tendon stiffness, and resistance to gap formation were measured. The results showed from the first cycle to the 10th cycle, there were no significant differences in gliding resistance between the three testing groups (p > 0.05). From the 50th cycle onwards, the friction was significantly lower in the cd-HA gel group than in the control group (p < 0.05). Neither breaking strength, nor tendon stiffness, nor resistance to gap formation of the repairs were significantly different between the three groups (p > 0.05).

Coated Materials, Biocompatible↗
PubMed2004

Gliding characteristics and gap formation for locking and grasping tendon repairs: a biomechanical study in a human cadaver model.

PURPOSE: The purpose of this study was to compare the frictional characteristics and mechanical properties of various locking and grasping suture techniques in a human in vitro model of flexor tendon repair. METHODS: Forty-five cadaveric human flexor digitorum profundus tendons were transected in zone II and repaired using 1 of 5 core suture methods (n = 9 per group): either grasping (modified grasping Kessler, modified Lee) or locking (Pennington, modified Pennington, locking Lee) loop suture techniques. All repairs used 4-0 Supramid looped core suture and an epitenon running suture of 6-0 nylon. Gliding resistance at the tendon-pulley interface was measured along with failure strength and gap formation. The force to produce 0.5-, 1.0-, 1.5-, and 2.0-mm gaps were measured. RESULTS: One of the locking repairs, the locking Lee, had a gliding resistance significantly higher than that of one of the grasping repairs (modified grasping Kessler) and the other 2 locking repairs (Pennington, modified Pennington) (p <.05). There was no significant difference between the other grasping (modified Kessler, modified Lee) and locking (Pennington, modified Pennington) suture configurations (p =.21). The maximum force of one of the locking repairs, the modified Pennington repair (48.0 N; standard deviation, 3.9) was significantly higher than the other locking and grasping repairs (p <.05). The force required to produce more than 1.5 mm of gap for the modified Pennington repair was also significantly higher than that for some of the other grasping (modified Kessler, modified Lee) and locking (Pennington) repairs (p <.05). CONCLUSIONS: The lack of significant difference in gliding resistance among the similarly designed modified grasping Kessler, Pennington, and modified Pennington repairs (overall mean, 0.87 N; standard deviation, 0.16) suggests that the locking loop configuration itself does not adversely affect tendon gliding resistance. The modified Pennington repair increased not only ultimate strength but also resistance to gap formation more than 1.5 mm.

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PubMed2004

Measurement of gliding resistance of the extensor pollicis longus and extensor digitorum communis II tendons within the extensor retinaculum.

PURPOSE: The etiology of spontaneous extensor pollicis longus (EPL) tendon rupture is still largely unknown. It is possible that friction within the sheath may play a role. The purposes of this study were to compare gliding resistance of the EPL tendon with that of the extensor digitorum communis tendon of the index finger (EDC II) and to find the wrist position that gives the EPL tendon the lowest gliding resistance. METHODS: Fifteen fresh-frozen cadavers were used. Gliding resistance was measured directly in 7 different wrist positions. RESULTS: The mean gliding resistance of the EPL tendon was 0.16 +/- 0.08 N and that of the EDC II tendon was 0.11 +/- 0.06 N. This difference was significant. There was also a significant effect on gliding resistance due to wrist position. For the EPL tendon, the gliding resistance was significantly greater in 60 degrees wrist flexion compared with all other wrist positions tested. Additionally the gliding resistance of the EPL in 30 degrees flexion, 60 degrees extension, and 15 degrees radial deviation was significantly higher than wrist positions of 30 degrees extension, neutral, and 30 degrees ulnar deviation. CONCLUSIONS: Positioning the wrist close to neutral flexion/extension and in some ulnar deviation minimizes the friction within the EPL sheath. Such positions may be advantageous for splinting patients at risk for EPL rupture.

Biomechanical Phenomena↗
PubMed2004

The effect of partial A2 pulley excision on gliding resistance and pulley strength in vitro.

PURPOSE: The purpose of this study was to investigate the effect of partial excision of the A2 pulley on the gliding resistance and the strength of the residual pulleys in a human in vitro model with or without tendon repair. METHODS: We used 32 cadaveric human fingers from 11 cadavers. The A2 pulley was excised successively 25%, 50%, and 75%, cutting either from the distal toward the proximal edge or from the proximal toward the distal edge. The peak gliding resistance between intact or repaired tendon and partially excised pulley was measured. After the gliding resistance test the pulley breaking strength and stiffness were measured. RESULTS: The peak gliding resistance exhibited the same statistical trends for the intact tendon and the repaired tendon groups. In the intact tendon groups the sequential excision of the A2 pulley from the distal toward the proximal edge had no significant effect on peak gliding resistance. With the A2 pulley cut from the proximal toward the distal edge, however, there was a significant increase in peak gliding resistance with 25% remaining pulley distally (0.82 N) compared with intact (0.42 N), 75% (0.57 N), and 50% (0.63 N) pulley remaining proximally. The 25% distal portion of the A2 pulley had a significantly higher breaking strength than the 25% proximal portion (160 N vs 96.7 N, respectively). Similarly the stiffness was greater in the distal portion compared with the proximal portion (120 N/mm vs 70.5 N/mm). CONCLUSIONS: After A2 pulley excision the size and location of the remaining pulley affects the resulting gliding resistance, stiffness, and failure strength. At the most extreme excision level tested the residual 25% distal segment of the pulley exhibited significantly greater peak gliding resistance compared with the 25% proximal segment, as well as greater strength and stiffness. If excision of the A2 pulley is limited to 50% (either proximally or distally), however, there is little increase in gliding resistance and the retained strength of the pulley is substantial. These data support the clinical practice of partial pulley excision, up to a limit of 50%, to facilitate exposure and tendon repair.

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