James P. Tasto

Bioabsorbable implants in orthopaedics: new developments and clinical applications.

The use of bioabsorbable implants in orthopaedic surgical procedures is becoming more frequent. Advances in polymer science have allowed the production of implants with the mechanical strength necessary for such procedures. Bioabsorbable materials have been utilized for the fixation of fractures as well as for soft-tissue fixation. These implants offer the advantages of gradual load transfer to the healing tissue, reduced need for hardware removal, and radiolucency, which facilitates postoperative radiographic evaluation. Reported complications with the use of these materials include sterile sinus tract formation, osteolysis, synovitis, and hypertrophic fibrous encapsulation. Further study is required to determine the clinical situations in which these materials are of most benefit.

Failure Mode of Suture Anchors as a Function of Insertion Depth

Background Surgeons can control not only the angle but also the depth of suture anchor placement during arthroscopic rotator cuff repair, although the tendency may be to place suture anchors on the deep side to avoid damage from prominent anchor eyelets. However, little information is available regarding possible effects of suture anchor depth on construct failure mechanisms. Hypothesis Anchor depth affects the mode of suture failure with physiologically relevant cyclic loads. Study Design Controlled laboratory study. Methods Metallic screw-in suture anchors loaded with No. 2 braided polyester sutures were inserted into the bovine infra-spinatus footprint with the eyelet proud, standard, or deep. Sutures were hand tied to create a closed loop. Constructs were cyclically loaded from 10 to 90 N and, if still intact at 500 cycles, taken to ultimate failure (maximum load). Results When clinical failure was defined as greater than 3-mm construct elongation, anchors placed with the eyelet deep experienced statistically earlier clinical failure via cutting of the suture through the bone (P <. 02). However, anchors placed at this level did not experience catastrophic failure during cyclic loading. The standard and proud anchors experienced 3 mm of elongation at a greater number of cycles, but the suture material degraded at the anchor eyelet, and a majority of these constructs broke during cyclic physiologic loading. At failure testing, the deep anchors had a significantly increased failure load (164 N) compared to standard (133 N) (P <. 04) and proud (113 N) anchors (P <. 005). Conclusion Varying the depth of suture anchor insertion changes the mechanical properties and mode of failure of suture anchor constructs. Clinical Relevance Surgeons should be aware of the effects of suture anchor depth and abrasive eyelet wear on construct failure during arthroscopic rotator cuff repair.

Pain Relief Through an Antinociceptive Effect After Radiofrequency Application

Background Many patients with chronic tendinosis have experienced early pain relief after application of bipolar radiofrequency treatment. Pathologic nerve ingrowth or nerve irritation in the tendon has been considered as a possible cause of the pain experienced with tendinosis. Hypothesis Bipolar radiofrequency treatment will ablate nerve fibers, resulting in pain relief. Study Design Controlled laboratory study. Methods Eighteen Sprague-Dawley rats were used in this study. Eight rats were treated with 2 points of bipolar radiofrequency applications applied to the hind paws with the Topaz microdebrider device, 6 sham rats had a needle applied to the hind paws, and there were 4 control rats. Tissues were processed for neural class III β-tubulin (TUJ-1) or calcitonin gene-related peptide (CGRP) immunohistochemistry by using the free-floating avidin-biotin complex technique. The numbers of TUJ1-immunoreactive and CGRP-immunoreactive nerve fibers in the epidermis were counted and compared with sham and control. Results The number of nerve fibers demonstrated by both the antibodies of TUJ1 and CGRP were significantly decreased (P = .0002-.002) during the first 2 weeks after bipolar radiofrequency treatment. Macroscopically, the foot pad showed 2 dimples on the surface after bipolar radiofrequency treatment. Although it still showed a scar after 7 days, after 14 days it looked no different than the untreated contralateral control foot pad and foot pad of the sham group. Conclusion Bipolar radiofrequency treatment induced acute degeneration and/or ablation of sensory nerve fibers. Clinical Relevance Degeneration or ablation of nerve fibers after bipolar radiofrequency treatment may explain the early postoperative pain relief after microtenotomy for tendinosis.

Visualization of the Extra-Articular Portion of the Long Head of the Biceps Tendon During Intra-Articular Shoulder Arthroscopy

PURPOSE To quantify the amount of the extra-articular long head of the biceps tendon (LHBT) seen during intra-articular shoulder arthroscopy by pulling the tendon into the joint with a probe through an anterior portal while viewing through a standard posterior portal. METHODS Intra-articular shoulder arthroscopy was performed on 10 forequarter cadaveric specimens. The extra-articular portion of the LHBT was evaluated by pulling the tendon into the joint with an arthroscopic probe inserted through an anterior portal. The tendon was marked at the pulley insertion on the humerus with a vascular clip before and after the tendon was pulled into the joint. An open deltopectoral approach was performed, and the amount of extra-articular tendon visualized was calculated as an absolute amount and in relation to nearby anatomic structures. RESULTS An additional 1.9 cm (range, 1.4 to 2.6 cm) of extra-articular LHBT was viewed by pulling the tendon into the joint with an arthroscopic probe through an anterior portal during shoulder arthroscopy. This represented 30.8% of the extra-articular portion of the tendon, 47.7% of tendon in the bicipital groove, and 76.3% of the tendon that lies under the area from the pulley insertion to the distal edge of the transverse humeral ligament. CONCLUSIONS During intra-articular shoulder arthroscopy, the extra-articular portion of the LHBT is incompletely visualized by pulling the tendon into the joint with a probe placed through an anterior portal while viewing through a standard posterior portal. CLINICAL RELEVANCE An additional extra-articular portion of the LHBT may be viewed by pulling the tendon into the joint with an arthroscopic probe during shoulder arthroscopy.

Nerve Regeneration After Radiofrequency Application

Background Many patients with chronic tendinosis have experienced early pain relief after application of bipolar radiofrequency treatment. It is hypothesized that the mechanism of action may be the acute degeneration and/or ablation of sensory nerve fibers. Hypothesis After ablation or degeneration by bipolar radiofrequency, nerve fibers will have the ability to regenerate with time. Study Design Controlled laboratory study. Methods Eighteen Sprague-Dawley rats were used in this study. These rats were divided into 3 groups (30, 60, and 90 days after bipolar radiofrequency). These rats were treated with 2 points of bipolar radiofrequency applications to the left hindpaws with the Topaz microdebrider device. Right hindpaws were used as the contralateral control. Tissues were processed for neural class III β-tubulin or calcitonin gene-related peptide immunohistochemistry by using the free-floating avidin biotin complex technique. The numbers of neural class III β-tubulin—immunoreactive and calcitonin gene-related peptide-immunoreactive nerve fibers in the epidermis were counted and compared with those in the contralateral control. Results Although the numbers of nerve fibers demonstrated by both the antibodies of neural class III β-tubulin and calcitonin gene-related peptide were significantly decreased (P < .0001) until 60 days after bipolar radiofrequency treatment, regeneration of the epidermal nerve fibers occurred 90 days after treatment. Conclusion Bipolar radiofrequency treatment induced degeneration of sensory nerve fibers immediately after treatment, but by 90 days posttreatment, there was evidence of complete regeneration. Clinical Relevance Early degeneration followed by later regeneration of nerve fibers after bipolar radiofrequency treatment may explain long-term postoperative pain relief after microtenotomy for tendinosis.

Augmentation of Tendon Healing With Butyric Acid–Impregnated Sutures Biomechanical Evaluation in a Rabbit Model

Background: Butyric acid (BA) has been shown to be angiogenic and to enhance transcriptional activity in tissue. These properties of BA have the potential to augment biological healing of a repaired tendon. Purpose: To evaluate this possibility both biomechanically and histologically in an animal tendon repair model. Study Design: Controlled laboratory study. Methods: A rabbit Achilles tendon healing model was used to evaluate the biomechanical strength and histological properties at 6 and 12 weeks after repair. Unilateral tendon defects were created in the middle bundle of the Achilles tendon of each rabbit, which were repaired equivalently with either Ultrabraid BA-impregnated sutures or control Ultrabraid sutures. Results: After 6 weeks, BA-impregnated suture repairs had a significantly increased (P < .0001) Young’s modulus and ultimate tensile strength relative to the control suture repairs. At 12 weeks, no statistical difference was observed between these measures. The histological data at 6 weeks demonstrated significantly increased (P < .005) vessel density within 0.25 mm of the repair suture in the BA-impregnated group. There was also an associated 42% increase in the local number of myofibroblasts in the BA samples relative to the controls at this time. By 12 weeks, these differences were not observed. Conclusion: Tendons repaired with BA-impregnated sutures demonstrated improved biomechanical properties at 6 weeks relative to control sutures, suggesting a neoangiogenic mechanism of enhanced healing through an increased myofibroblast presence. Clinical Relevance: These findings demonstrate that a relatively simple alteration of suture material may augment early tendon healing to create a stronger repair construct during this time.

The use of the supraclavicular fossa portal in arthroscopic rotator cuff repair

SUMMARY Advances in arthroscopic technology allow rotator cuff repair through a minimally invasive approach. However, fixation of the rotator cuff tendon to suture anchors can be tedious and time consuming. The supraclavicular fossa portal allows improved access to the tear for passing suture. The authors describe the relevant anatomy, positioning, and surgical technique for use of the supraclavicular fossa portal to simplify arthroscopic rotator cuff repair.

Tendon Treatment Center

A “Tendon Treatment Center” can be established as part of an established orthopedic practice. Ideally, access to a number of modalities, which will be described, will further enhance the value of this center. Conservative care of tendinosis is currently part of clinical practice, and physical therapy is either an in-house service or referred out. MRI or ultrasound studies are diagnostic tools that aid in the location of the pathology as well as in the confirmation of tendinosis. Access to the use of bipolar radiofrequency (bRf) micro-tenotomy (Topaz; ArthroCare, Sunnyvale, CA) is readily available to all orthopedic surgeons. The procedure is done at an ambulatory surgery center. One may choose to lease a low energy extracorporeal shockwave therapy unit (ESWT), or use a high-energy machine that is leased by an ambulatory surgery center or hospital. Once these modalities and services are secured and/or contracted, then the orthopedists may begin to notify colleagues and referral physicians of this “Center.” Full details of the proposed mechanism of action and the science behind bRf microtenotomy and ESWT is described. The economic advantages of each of these treatment modalities are discussed as well.

Failure Mode of Suture Anchors as a Function of Insertion Depth (SS-32)

BACKGROUND Surgeons can control not only the angle but also the depth of suture anchor placement during arthroscopic rotator cuff repair, although the tendency may be to place suture anchors on the deep side to avoid damage from prominent anchor eyelets. However, little information is available regarding possible effects of suture anchor depth on construct failure mechanisms. HYPOTHESIS Anchor depth affects the mode of suture failure with physiologically relevant cyclic loads. STUDY DESIGN Controlled laboratory study. METHODS Metallic screw-in suture anchors loaded with No. 2 braided polyester sutures were inserted into the bovine infra-spinatus footprint with the eyelet proud, standard, or deep. Sutures were hand tied to create a closed loop. Constructs were cyclically loaded from 10 to 90 N and, if still intact at 500 cycles, taken to ultimate failure (maximum load). RESULTS When clinical failure was defined as greater than 3-mm construct elongation, anchors placed with the eyelet deep experienced statistically earlier clinical failure via cutting of the suture through the bone (P < .02). However, anchors placed at this level did not experience catastrophic failure during cyclic loading. The standard and proud anchors experienced 3 mm of elongation at a greater number of cycles, but the suture material degraded at the anchor eyelet, and a majority of these constructs broke during cyclic physiologic loading. At failure testing, the deep anchors had a significantly increased failure load (164 N) compared to standard (133 N) (P < .04) and proud (113 N) anchors (P < .005). CONCLUSION Varying the depth of suture anchor insertion changes the mechanical properties and mode of failure of suture anchor constructs. CLINICAL RELEVANCE Surgeons should be aware of the effects of suture anchor depth and abrasive eyelet wear on construct failure during arthroscopic rotator cuff repair.