Biomechanical Study of a Multifilament Stainless Steel Cable Crimp System Versus a Multistrand Ultra-High Molecular Weight Polyethylene Polyester Suture Krackow Technique for Achilles Tendon Rupture Repair.

Currently, Achilles tendon rupture repair is surgically addressed with an open or minimally invasive approach using a heavy, nonabsorbable suture in a locking stitch configuration. However, these sutures have low stiffness and a propensity to stretch, which can result in gapping at the repair site. Our study compares a new multifilament stainless steel cable-crimp repair method to a standard Krackow repair using multistrand, ultra-high molecular weight polyethylene polyester sutures. Eight matched pairs of cadavers were randomly assigned for Achilles tendon repair using either Krackow technique with polyethylene polyester sutures or the multifilament stainless steel cable-crimp technique. Each repair was cyclically loaded from 10 to 50 N for 100 loading cycles, followed by a linear increase in load until complete failure of the repair. During cyclic loading, 4 of the 8 Krackow polyethylene polyester suture repairs failed, whereas none of the multifilament stainless steel cable crimp repairs failed. Load to failure was greater for the multifilament stainless steel cable crimp repairs (321.03 ± 118.71 N) than for the Krackow polyethylene polyester suture repairs (132.47 ± 103.39 N, p = .0078). The ultimate tensile strength of the multifilament stainless steel cable crimp repairs was also greater than that of the Krackow polyethylene polyester suture repairs (485.69 ± 47.93 N vs 378.71 ± 107.23 N, respectively, p = .12). The mode of failure was by suture breakage at the crimp for all cable-crimp repairs and by suture breakage at the knot, within the tendon, or suture pullout for the polyethylene polyester suture repairs. The multifilament stainless steel cable crimp construct may be a better alternative for Achilles tendon rupture repairs.

Biomechanical comparison of double grasping repair versus cross-locked cruciate flexor tendon repair.

PURPOSE: This study was conducted to compare the in vitro biomechanical properties of tensile strength and gap resistance of a double grasping loop (DGL) flexor tendon repair with the established four-strand cross-locked cruciate (CLC) flexor tendon repair, both with an interlocking horizontal mattress (IHM) epitendinous suture. The hypothesis is that the DGL-IHM method which utilizes two looped core sutures, grasping and locking loops, and a single intralesional knot will have greater strength and increased gap resistance than the CLC-IHM method. METHODS: Forty porcine tendons were evenly assigned to either the DGL-IHM or CLC-IHM group. The tendon repair strength, 2-mm gap force and load to failure, was measured under a constant rate of distraction. The stiffness of tendon repair was calculated and the method of repair failure was analyzed. RESULTS: The CLC-IHM group exhibited a statistically significant greater resistance to gapping, a statistically significant higher load to 2-mm gapping (62.0 N), and load to failure (99.7 N) than the DGL-IHM group (37.1 N and 75.1 N, respectively). Ninety percent of CLC-IHM failures were a result of knot failure whereas 30 % of the DGL-IHM group exhibited knot failure. CONCLUSIONS: This study demonstrates that the CLC-IHM flexor tendon repair method better resists gapping and has a greater tensile strength compared to the experimental DGL-IHM method. The authors believe that while the DGL-IHM provides double the number of sutures at the repair site per needle pass, this configuration does not adequately secure the loop suture to the tendon, resulting in a high percentage of suture pullout and inability to tolerate loads as high as those of the CLC-IHM group.

The effects of framing and fear on ratings and impact of antimarijuana PSAs.

A laboratory experiment, funded by the U.S. National Institutes of Health, involved 243 U.S. undergraduate students and employed a 2 (gain-framed vs. loss-framed) × 2 (high vs. low threat) plus control group pretest-posttest experimental design to assess the combined effects of frame (gain vs. loss) and level of threat of public service announcements (PSAs) about marijuana on attitudes, beliefs, and intentions related to marijuana, as well as the relationship of message condition to ratings of PSAs. Results suggest that loss-framed messages may lead to greater perceived threat, as well as reactance, and gain-framed messages may lead to a greater reduction in positive attitudes toward marijuana than loss-framed messages. Finally, frame and threat may interact in a complex way. Further research is suggested to replicate these findings. A substantial body of carefully crafted and systematic research studies examining both content and features of messages increasingly informs mass media prevention efforts, including the development of public service announcements (PSAs). Although the significance of messages on commercial broadcast stations may be diminishing with the increasing role and impact of new media, many of the basic questions addressed by this research are likely to apply across media channels. Nonetheless, important questions about what makes a message effective in changing an individual's attitudes or behavior remain to be answered. In this paper, the authors focus on two theoretically derived strategies that offer possibilities for developing persuasive messages: framing and threat.

Analysis of a knotless flexor tendon repair using a multifilament stainless steel cable-crimp system.

PURPOSE: To compare the biomechanical and technical properties of flexor tendon repairs using a 4-strand cruciate FiberWire (FW) repair and a 2-strand multifilament stainless steel (MFSS) single cross-lock cable-crimp system. METHODS: Eight tests were conducted for each type of repair using cadaver hand flexor digitorum profundus tendons. We measured the required surgical exposure, repair time, and force of flexion (friction) with a custom motor system with an inline load cell and measured ultimate tensile strength (UTS) and 2-mm gap force on a servo-hydraulic testing machine. RESULTS: Repair time averaged less than 7 minutes for the 2-strand MFSS cable crimp repairs and 12 minutes for the FW repairs. The FW repair was performed with 2 cm of exposure and removal of the C-1 and A-3 pulleys. The C-1 and A-3 pulleys were retained in each of the MFSS cable crimp repairs with less than 1 cm of exposure. Following the FW repair, the average increase in friction was 89% compared with an average of 53% for the MFSS repairs. Six of the 8 MFSS specimens achieved the UTS before any gap had occurred, whereas all of the FW repairs had more than 2 mm of gap before the UTS, indicating that the MFSS was a stiffer repair. The average UTS appeared similar for both groups. CONCLUSIONS: We describe a 2-strand multifilament stainless steel single cross-lock cable crimp flexor repair system. In our studies of this cable crimp system, we found that surgical exposure, average repair times, and friction were reduced compared to the traditional 4-strand cruciate FW repair. While demonstrating these benefits, the crimp repair also produced a stiff construct and high UTS and 2-mm gap force. CLINICAL RELEVANCE: A cable crimp flexor tendon repair may offer an attractive alternative to current repair methods. The benefits may be important especially for flexor tendon repair in zone 2 or for the repair of multiple tendons.

Biomechanical evaluation of a cable-crimp system designed for repair of tendons and ligaments in the hand.

The goal of this study was to evaluate the biomechanical properties of an alternative method for connecting sutures using a crimp and to compare this method with a knot connection. Multifilament stainless steel suture (3-0 USP size) was connected by means of knot tying or crimp application and compared with FiberWire (3-0 USP size) connected by knot tying. Ultimate tensile strength (UTS) and stiffness were tested on a servohydraulic testing machine. The total UTS of the crimped constructs was significantly stronger and stiffer than the knotted groups, although the strength per strand was not statistically significant. Crimps offer an alternative method for connecting sutures. They have mechanical advantages over knot tying and allow the connection of multiple suture strands as well as the additional advantage of attaching both sides of the repair independently. This may provide precise pretensioning and potentially reduced surgical exposure.

Surface markers for locating the pulleys and flexor tendon anatomy in the palm and fingers with reference to minimally invasive incisions.

PURPOSE: Palm and finger pulley anatomy has been well described in relation to osseous structures. The goal of this study was to describe skin surface markers that locate the underlying flexor tendon and pulley system. We describe the anatomic detail of these structures and provide a guide for the surgeon for making small incisions. Using this approach, extensile exposure can be avoided, and the integrity of the complex pulley system is maintained. METHODS: We dissected 12 palms and 48 fingers in 12 cadaver hands. We marked the palm and finger creases with methylene blue before dissection. We removed palm skin, finger skin, and subcutaneous tissue over the flexor tendon sheath and retained a 2-mm strip of each skin crease in its native position. We divided the palm and palmar surface of the fingers into 4 distinct zones and measured the location of the proximal and distal extent of each pulley and the tendon anatomy relative to the proximal and distal skin crease. RESULTS: We documented the location of the proximal and distal extent of the annular and cruciate pulleys as well as the decussation of the flexor digitorum superficialis (FDS) tendon and Camper chiasm. The results allow us to establish a relationship between the skin creases and underlying anatomy by dividing the palm and finger into 4 zones. In zone A, in the palm, the A2 pulley is located in the distal third and the FDS decussation is at the proximal extent of the A2 pulley. Zone B is in the proximal phalanx and A2 lies in the proximal third of this zone, whereas the Camper chiasm lies in the middle third. Zone C is in the middle phalanx and A4 and the insertion of FDS lie in the middle third of this zone. Zone D lies in the distal phalanx and the flexor digitorum profundus tendon inserts into the middle third of this zone. CONCLUSIONS: Skin creases can be used as surface markers to accurately locate the underlying pulley and tendon system and plan for limited incisions. CLINICAL RELEVANCE: These anatomic descriptions can aid surgeons in preoperative planning and may also help minimize the required exposure for flexor tendon repair and other surgery in the fingers and palm.

Comparison of a new multifilament stainless steel suture with frequently used sutures for flexor tendon repair.

PURPOSE: To investigate the mechanical properties of some common suture materials currently in use and compare them with a new multifilament stainless steel suture. METHODS: We investigated the mechanical properties of 3-0 and 4-0 Fiberwire, 3-0 Supramid, 3-0 Ethibond, and a new 3-0 and 4-0 multifilament stainless steel suture. All suture material was tested in a knotted configuration and all but the Supramid was tested in an unknotted configuration. We measured the load, elongation at failure, and stiffness during both tests. RESULTS: The 4-0 multifilament stainless steel showed the least elongation, whereas the 3-0 multifilament stainless steel withstood the highest load of any material in both the knotted and unknotted tests. There was no difference in stiffness between the 3-0 and 4-0 multifilament stainless steel when untied; however, the 3-0 multifilament stainless steel was stiffer when tied. Soaking in a saline solution had no significant effect on the ultimate load, elongation at failure, or stiffness of any of the sutures. The 3-0 Fiberwire and 3-0 Ethibond required at least 5 throws to resist untying. CONCLUSIONS: Multifilament stainless steel exhibited promising mechanical advantages over the other sutures tested. More research is needed to determine how this material will affect the clinical outcomes of primary flexor tendon repair. CLINICAL RELEVANCE: With a secure attachment to the tendon, the multifilament stainless steel's lower elongation and better knot-holding ability may result in a higher force to produce a 2-mm gap and a higher ultimate tensile strength in a tendon repair.

Wrist arthroscopy using a shoulder traction boom.

Overhead boom traction is commonly used in shoulder arthroscopy. In this article, we describe using overhead boom traction in wrist arthroscopy. The advantages are circumferential fluoroscopic access; lack of central post interference with instrumentation; and continuous, uninterrupted traction without need for frequent "dialing up" of traction tower height.

Long-term results of tendon shortening trapeziometacarpal arthroplasty.

Multiple soft tissue arthroplasties have been described for reconstruction of trapeziometacarpal arthritis. Trapeziectomy with abductor pollicis longus tendon shortening has been reported to have favorable short-term results, with 95% to 100% good or excellent pain relief at an average of 18 to 31 months. No long-term results of this reconstruction have been published. In the current study, 29 abductor pollicis longus shortening arthroplasties were reviewed at an average of 5.1 years. Although 83% of patients experienced good or excellent pain relief, pinch weakness, a small arthroplasty space, and first metacarpal instability were present in numerous patients. Because of these problems observed at long-term followup, the authors now use ligament reconstruction tendon interposition as the primary trapeziometacarpal arthroplasty.

Advances in Microsurgery.

The beginnings of microsurgery date back to the early part of the century. In 1906, the first description of small vessel anastomosis was presented to the Johns Hopkins Medical Society by Alexis Carrel, who eventually won the Nobel Prize for his work in 1912. The next major advance, reported by Jacobson and Suarez in 1960, was the anastomosis of 1mm vessels. This feat was a pivotal accomplishment and soon became clinically feasible with the manufacture of fine needles (50µ to 100µ) and sutures measuring between 15µ and 20µ, or approximately three times the size of a human red blood cell. Two years later, Malt performed a landmark operation the first replantation of an upper extremity above the elbow and soon after, Susumi Tamai of Japan successfully reattached a completely amputated thumb. The first toe-to-thumb transplant was performed in the early 1970s, and, within a few years, free microvascular muscle and bone transplantation had been described. By the early 1980s, microsurgical procedures had undergone a dramatic evolution, seeing the development of an expansive array of microvascular alternatives to address a wide variety of clinical problems.