Biomedical subjects
Peter C Amadio
Publications and source records attributed to Peter C Amadio.
Extradigital glomus tumors: a 20-year experience.
OBJECTIVE: To review a large series of extradigital glomus tumors in order to gain a better understanding of their presentation and provide guidelines to aid in their diagnosis and treatment. PATIENTS AND METHODS: We performed a retrospective review of all extradigital glomus tumors seen at our institution during a 20-year period (1985-2005) to document the incidence of the classic triad of symptoms, the duration of symptoms, the contribution of imaging to making a definitive diagnosis, and the effectiveness of treatment. RESULTS: Fifty-six different patients with extradigital glomus tumors presented as follows: glomus tumors in the hand (3), wrist (4), forearm (11), elbow (4), arm (4), shoulder (2), buttock (1), thigh (5), knee (10), leg (3), ankle (2), foot (2), back (1), nose (1), cheek (1), ear lobe (1), and trachea (1). Forty-eight patients presented with pain and localized tenderness, but only 1 patient presented with cold Intolerance. The average duration of symptoms was greater than 7 years, with most patients being evaluated previously and having their conditions misdiagnosed. Magnetic resonance imaging proved to be the most useful modality for localization of these lesions. Surgical resection was the definitive treatment and generally provided immediate and sustained pain relief. CONCLUSIONS: Extradigital glomus tumors are not a rare subgroup of glomus tumors. Treatment outcomes are excellent, but misdiagnosis and delayed diagnosis are common. Improved guidelines regarding symptoms and diagnosis of these neoplasms may reduce the morbidity, ensuing chronic pain, and psychiatric consequences of delayed diagnosis or misdiagnosis.
A comparison of fusion, trapeziectomy, and silastic replacement for the treatment of osteoarthritis of the trapeziometacarpal joint.
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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.
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.
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.
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.
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.
Thalidomide--cost and development.
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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.
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.
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).
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.
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.
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.
Reducing friction by chemically modifying the surface of extrasynovial tendon grafts.
In this study we evaluated methods to reduce the friction of an extrasynovial tendon under a pulley in vitro. The surface of canine peroneus longus (PL) tendons was modified with gelatin and/or hyaluronic acid (HA) under different conditions. The gliding resistance between treated or control tendons and the canine digital flexor pulley was measured during 500 cycles of simulated flexion/extension. After 500 cycles, the gliding resistance of normal PL tendon increased 10-fold (p<0.05), while the gliding resistance of tendons coated with carbodiimide derivatized gelatin (cd-gelatin) or carbodiimide derivatized gelatin/HA (cd-gelatin-HA) did not increase significantly. The PL tendon treated with cd-gelatin-HA had a similar friction response during the repetitive motion as the intrasynovial flexor digitorum profundus (FDP) tendon. Scanning electron microscopy after 500 cycles of motion showed that the tendon surface in the group treated with cd-gelatin-HA appeared smoother than tendons in the other groups.
Vascular pathologic changes in the flexor tenosynovium (subsynovial connective tissue) in idiopathic carpal tunnel syndrome.
We used the Verhoeff-van Gieson stain method to identify histopathology and to localize elastin in the subsynovial connective tissue of the tendon sheath (SSCT) of the middle finger flexor digitorum superficialis (FDS) within the carpal tunnel in 10 carpal tunnel syndrome (CTS) patients and 10 control cadaver specimens. Normal SSCT stained for elastin abundantly around blood vessels and within vessel walls. The typical pathologic findings of CTS patients SSCT included vascular proliferation, vascular hypertrophy, and vascular obstruction with wall thickening. There was a decreased amount of elastin in the blood vessel walls and around the vessels in the CTS patients as well. The changes in the carpal tunnel patients were particularly remarkable in that the patients were younger than the controls, yet showed findings more characteristic of chronic degeneration.