Amadio, Peter C.

ABSTRACTThe objective of this study was to evaluate the correlations between deformation and displacement of median nerve and flexor tendons during finger motion in the carpal tunnel for both carpal tunnel syndrome (CTS) patients and healthy controls. Sixty‐two wrists of 31 asymptomatic volunteers and fifty‐one wrists of 28 idiopathic CTS patients were evaluated by ultrasound. The displacement of the median nerve and the middle finger flexor digitorum superficialis (FDS) tendon, as well as area, perimeter, aspect ratio of a minimum enclosing rectangle, and circularity of the median nerve were measured in finger extension and flexion positions. Deformation indices were defined as the ratios of indices in finger extension and flexion positions. The correlations between displacement and deformation indices were evaluated. There were significant correlations between nerve palmar–dorsal displacement and deformation indices (p < 0.05). The aspect ratio deformation index showed the strongest correlation to palmar–dorsal displacement of the nerve (−0.572, p < 0.01). This study showed that there is a relationship between median nerve deformation indices and nerve palmar–dorsal displacement in the carpal tunnel. Since the highest correlations were between palmar–dorsal nerve displacement direction and aspect ratio deformation index, these parameters may be helpful to understand the pathophysiology of CTS. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1876–1880, 2013

AbstractTendon‐to‐bone integration is a great challenge for tendon or ligament reconstruction regardless of use of autograft or allograft tendons. We mineralized the tendon, thus transforming the tendon‐to‐bone into a “bone‐to‐bone” interface for healing. Sixty dog flexor digitorum profundus (FDP) tendons were divided randomly into five groups: (1) normal FDP tendon, (2) CaP (non‐extraction and mineralization without fetuin), (3) CaPEXT (Extraction by Na2HPO4 and mineralization without fetuin), (4) CaPFetuin (non‐extraction and mineralization with fetuin), and (5) CaPEXTFetuin (extraction and mineralization with fetuin). The calcium and phosphate content significantly increased in tendons treated with combination of extraction and fetuin compared to the other treatments. Histology also revealed a dense mineral deposition throughout the tendon outer layers and penetrated into the tendon to a depth of 200 µm in a graded manner. Compressive moduli were significantly lower in the four mineralized groups compared with normal control group. No significant differences in maximum failure strength or stiffness were found in the suture pull‐out test among all groups. Mineralization of tendon alters the interface from tendon to bone into mineralized tendon to bone, which may facilitate tendon‐to‐bone junction healing following tendon or ligament reconstruction. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1713–1719, 2013

ABSTRACTWe compared the mechanical force of tendon‐to‐bone repair techniques for flexor tendon reconstruction. Thirty‐six flexor digitorum profundus (FDP) tendons were divided into three groups based upon the repair technique: (1) suture/button repair using FDP tendon (Pullout button group), (2) suture bony anchor using FDP tendon (Suture anchor group), and (3) suture/button repair using FDP tendon with its bony attachment preserved (Bony attachment group). The repair failure force and stiffness were measured. The mean load to failure and stiffness in the bony attachment group were significantly higher than that in the pullout button and suture anchor groups. No significant difference was found in failure force and stiffness between the pullout button and suture anchor groups. An intrasynovial flexor tendon graft with its bony attachment has significantly improved tensile properties at the distal repair site when compared with a typical tendon‐to‐bone attachment with a button or suture anchor. The improvement in the tensile properties at the repair site may facilitate postoperative rehabilitation and reduce the risk of graft rupture. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1720–1724, 2013

In a review of the Mayo Clinic files, 17 biopsy-proven cases of metastatic tumors of the foot and ankle were found; 4 additional cases were considered to have metastatic disease on the basis of clinical and radiographic evidence but no histological confirmation was available. Lung, kidney, and colon were the most common sites of the primary tumors. The patients survived as long as 28 months after discovery of the metastasis. Treatment consisted of individualized combinations of orthotics, surgery, and radiotherapy to maintain mobility. In 9 of these 17 cases, no primary lesion was identified at the time the metastasis was diagnosed. Metastatic tumors of the foot present special problems in diagnosis and management.

Background We have recently reported that interpositional synovium grafts from tendon sheath have a potential to accelerate tendon healing when implanted at the repair site. The purpose of this study was to investigate the effect of orientation of the synovium after synovium graft transplantation, by comparing the ability of cells from the visceral and parietal surfaces to migrate into the tendon in a canine tissue culture model. Methods The synovium graft was placed within a complete tendon laceration, with either the visceral or parietal surface facing the proximal end of the lacerated tendon. The number of migrating cells was quantified by a cell migration assay. Qualitative immunohistochemistry and confocal laser microscopy were also used at day 10. Results Many labeled synovial cells were observed within the tendon to which the visceral surface of the synovium graft was facing. Migrated cells were also observed on the parietal side, but there were fewer cells compared to visceral surface cells. Migrating cells all expressed α-smooth muscle actin. Conclusion We found that graft orientation affected cell migration. Whether this finding has clinical significance awaits in vivo study.

The purpose of this study was to compare two different methods of joining tendons of similar and dissimilar sizes between recipient and donor tendons for flexor tendon grafts. Flexor digitorum profundus (FDP) and peroneus longus (PL) canine tendons were harvested and divided into four groups. The repair technique we compared was a step-cut (SC) suture and a Pulvertaft weave (PW). FDP tendons were significantly larger in diameter than PL tendons ( p < 0.05). The volume of the SC repairs using either FDP or PL tendon as a graft was significantly smaller than PW repairs ( p < 0.05). The ultimate load to failure and repair stiffness in FDP graft tendons significantly increased compared with the PL graft tendons ( p < 0.05). The SC suture can be used as an alternative to the PW, with similar strength and less bulk for repairs using graft tendons of similar diameter. Surgeons should be aware of the effect of graft tendon size and repair method on strength and bulk when performing flexor tendon grafts.

The purpose of this study was to describe a modification of the Massachusetts General Hospital (MMGH) tendon repair and to compare it with three other suture techniques. Twenty human flexor digitorum profundus (FDP) tendons were randomly assigned to the modified Pennington (MP) suture and the MMGH suture. These were compared to the modified Kessler (MK) and Massachusetts General Hospital (MGH) sutures, using data from a previous study. All tendons were repaired with a similar epitendinous stitch and core sutures of 4-0 FiberWire. There was no significant difference in the normalized gliding resistance within the two-strand or four-strand core repair groups. The MP suture had significantly higher 2 mm gap force and ultimate load to failure than the MK suture. The MMGH suture had significantly higher 2 mm gap force and maximum failure ultimate load than the MGH suture. All repairs failed by knot unravelling.

Background The etiology of carpal tunnel syndrome (CTS) remains idiopathic in many cases. Noninflammatory fibrosis of the subsynovial connective tissue (SSCT) within the carpal tunnel is common in CTS, and some clinicians have hypothesized that this fibrosis might be a cause rather than an effect of CTS. An animal model in which to test this hypothesis would be useful. The principal objective of this study was to investigate the effect of a surgical injury on SSCT fibrosis and median nerve function within the carpal tunnel in an in vivo rabbit model. Methods Rabbits were sacrificed 12 weeks after surgery and were evaluated by mechanical testing, histology, transmission and scanning electron microscopy, and electrophysiology. Results SSCT fibroblast density ( p<0.0001) and collagen fiber size ( p=0.0004) were significantly higher, and the median nerve distal motor amplitude was significantly lower ( p=0.0018), in the tendon injury group SSCT than in either the sham or control groups. Conclusions Our findings are similar to those seen in patients with carpal tunnel syndrome and suggest that the tendon injury procedure may be the basis of a new animal model of SSCT injury and, possibly, CTS.

Barbed sutures and connecting devices have been historically described and used in flexor tendon tenorrhaphies. With the improvement in biomaterial, we have witnessed recently the resurgence of this concept. In this article, we review the historical use of barbed devices in repairing flexor tendons and explore the available barbed surgical devices that have been described in recent years.

Tendon disuse, or stress deprivation, frequently accompanies clinical disorders and treatments, yet the metabolism of tendons subject to stress deprivation has rarely been investigated systematically. The effects of stress deprivation on canine flexor tendon were investigated in this study. One adult canine forepaw was suspended for 21 or 42 days. Control forepaws were collected from dogs that had no intervention on their limbs and paws. The expression of collagen I and III was not significantly altered in the tendons disused for 21 days but was significantly decreased at 42 days ( P < 0.03). The expression of collagen II, aggrecan, decorin, and fibronectin was significantly decreased in the tendons in the suspended limbs at 21 days ( P < 0.002) and further reduced at 42 days. With stress deprivation, the expression of matrix metalloproteinase 2 (MMP2) was significantly increased ( P < 0.004) at 21 and 42 days. The expression of MMP3 was significantly decreased at 21 and 42 days ( P < 0.03). The expression of MMP13 was not altered with stress deprivation at 21 and 42 days. The expression of MMP14 was significantly increased at 21 days ( P = 0.0015) and returned to the control level at 42 days. Tissue inhibitor of metalloproteinase 1 (TIMP1) expression was decreased after the limbs were suspended for 42 days ( P = 0.0043), but not 21 days. However, TIMP2 expression was not significantly different from control at 21 or 42 days. Furthermore, the cross-sectional area of the stress-deprived tendons at 42 days was decreased compared with the control group ( P < 0.01). The intervention method in this study did not result in any alteration of stiffness of the tendon. Our study demonstrated that stress deprivation decreases the anabolic process and increases the catabolic process of extracellular matrix in flexor tendon.