Growth Factor Expression During Healing in 3 Distinct Tendons.

Purpose: We investigated unique tendon growth-factor expression profiles over time in response to simultaneous, similar injuries. Characterizing these genetic differences lays the foundation for creating targeted, tendon-specific therapies and provides insight into why current growth-factor treatments have success in some applications but not others. Methods: The left fourth digital flexor, triceps, and supraspinatus tendons in 24 rats were cut to 50% of their transverse width at the midbelly under anesthesia. On postoperative days 1, 3, 5, 7, and 14, randomly selected rats were sacrificed, and the damaged tendons were excised and flash-frozen in liquid nitrogen. The expressional fibroblast growth factor 1, bone morphogenic protein 13, and transforming growth factor ß-1 were measured at each time point and compared to their respective, uninjured levels with real-time polymerase chain reaction. Results: The digital flexor tendon showed exponentially elevated expression of all 3 factors over the preinjury baseline values. Expression in the triceps and supraspinatus had more variation over time. The triceps tendon showed a considerable decrease of transforming growth factor ß-1 and bone morphogenic protein 13 expression. The supraspinatus tendon had statistically significant increases of both transforming growth factor ß-1 and bone morphogenic protein 13 expression relative to preoperative, uninjured levels, with a nonstatistically significant decrease of fibroblast growth factor 1. Conclusions: Our study suggests different tendons express their own unique growth-factor profiles after similar, simultaneous injuries. The digital flexor showed particularly high, sustained levels of growth-factor expression in comparison to the supraspinatus and triceps, suggesting that variable dosing may be necessary for growth-factor therapies aimed at supplementing innate responses in these different tendon types. Clinical relevance: These data show different tendons express unique trends of growth-factor expression over time in response to injury, suggesting each unique tendon may require specific dosing or knockdown therapies. These observations serve as a foundation for more tendon-specific questioning, experimentation, and therapeutic design.

Use of high-speed burr and water-based lubricant in the partial removal of surgical plates: A technique Guide.

Implant removal comprises 5% of all orthopaedic surgery procedures performed annually. Surgical indications range from implant failure, infection, non-union, and symptomatic hardware. Intra-operatively, surgeons need to prepare for complications including bony overgrowth, cold-welding, broken screws, and stripped screw heads. Large anatomic dissections required for complete hardware removal place the patient at increased risk of complications due to increased operating time and larger dissections. The authors present a safe and effective technique for the partial removal of surgical implants. The technique utilizes a high-speed burr to cut surgical plates, minimizing the total dissection and operative time. Sterile surgical laps covered in water-based lubricant capture metal debris to reduce tissue contamination as well as surgeon exposure to metal particles.

Septic Arthritis of the Shoulder: A Comparison of Treatment Methods.

INTRODUCTION: In-hospital outcomes were compared among patients with shoulder septic arthritis treated with arthrocentesis, open irrigation and débridement, or arthroscopic irrigation and débridement. METHODS: The Nationwide Inpatient Sample database was queried for all cases of native shoulder septic arthritis between 2002 and 2011. Patient demographics, comorbidities, and hospitalization complications were compared for the shoulder arthrocentesis (nonsurgical) and open or arthroscopic irrigation and débridement (surgical) groups. RESULTS: Data for 7,145 patients were analyzed. Medical comorbidities and complications were more common in the nonsurgical group than in the open surgical group (septicemia, 36.7% versus 23.6%, P < 0.001; death, 6.5% versus 2.5%, P < 0.001; pneumonia, 11.3% versus 6.2%, P < 0.001; septic shock, 4% versus 2.2%, P < 0.001; and urinary tract infection, 15.5% versus 10.2%, P < 0.001). The mean length of stay was longer in the nonsurgical group compared with the open surgical group (11.5 days versus 10.5 days, respectively; P = 0.002) and the percentage of patients discharged to home was lower (55.1% versus 64.0%, respectively; P < 0.001). Compared with the open surgical group, the arthroscopic surgical group had higher incidences of perioperative septicemia and urinary tract infection and similar average length of stay, hospital charges, and blood transfusion rates, but a lower incidence of osteomyelitis (P < 0.001). In a subgroup of patients with septicemia, Staphylococcus aureus was the most frequently cultured causative organism. DISCUSSION: Septic arthritis in the shoulder is challenging to manage, and patients often have medical comorbidities and complications. In this study, the nonsurgically treated patients had substantially more preexisting comorbidities and in-hospital complications than the surgically treated patients had, which likely contributed to the longer average length of stay and lower discharge percentage in the nonsurgical group. CONCLUSION: Patients with septic arthritis of the shoulder frequently experience substantial systemic complications regardless of the treatment method. Septicemia was a common complication among all treatment groups, with cultures most frequently indicating Staphylococcus aureus as the causative organism. LEVEL OF EVIDENCE: Therapeutic level III.

Current flexor and extensor tendon motion regimens: a summary.

This article summarizes select multinational early motion protocols. Included are flexor and extensor protocols for digital tendon repair in many forms. Custom orthosis design, exercise regimens, and advanced techniques are examples of what to expect. The goal of the article is to expose the reader to new ideas, educate regarding advanced techniques in tendon rehabilitation, and stimulate independent study to further the reader's skill set.

Biomechanical analysis of partial flexor tendon lacerations in zone II of human cadavers.

PURPOSE: The aims of this study were to examine nonrepaired 90% partial lacerations of human cadaver flexor digitorum profundus (FDP) tendon after simulated active motion, and to assess the residual ultimate tensile strength. METHODS: Partial, transverse zone II flexor tendon lacerations were made in the volar 90% of the tendon substance in 10 FDP tendons from 5 fresh-frozen human cadaver hands. The tendons were cycled in the curvilinear fashion described by Greenwald 500 times to a tension 25% greater than the maximum in vivo active FDP flexion force measured by Schuind and colleagues. The tendons were then loaded to failure using the same curvilinear model. RESULTS: No tendons ruptured during cycling. Triggering occurred in 3 tendons. All 3 began triggering early in the cycling process, and continued to trigger throughout the remainder of the 500 cycles. The observed triggering mechanics in each case involved the interaction of the proximal face of the lacerated tendon with Camper's chiasm and the pulley edges during extension. The load to failure value of the 90% partially lacerated tendons averaged 141.7 +/- 13 N (mean +/- standard deviation). Tendon failure occurred by delamination of the intact collagen fibers from the distal, discontinuous 90% of the tendon. CONCLUSIONS: Cadaveric transverse zone II partial flexor tendon lacerations have residual tensile strength greater than the force required for protected active mobilization.

Effects of the deep anterior oblique and dorsoradial ligaments on trapeziometacarpal joint stability.

PURPOSE: Osteoarthritis of the trapeziometacarpal (TMC) joint of the thumb affects as many as 25% of postmenopausal women and 5% of middle-aged men. This study investigated the relative contribution of the dorsoradial ligament (DRL) and the deep anterior oblique ligament (dAOL) to the stability of the TMC joint. This knowledge will improve our understanding of the pathomechanics of osteoarthritis at the base of the thumb and may help to design novel reconstructive surgical procedures. METHODS: Seventeen intact cadaver hands were dissected to reveal the DRL and dAOL. Either the DRL or dAOL was transected randomly, physiologic muscle loads were applied to simulate lateral key pinch or thumb opposition, or a 3-dimensional magnetic tracking system was used to record the position of the thumb metacarpal relative to the trapezium. The differences in the 3-dimensional positions between the control and transected states were determined. RESULTS: In lateral pinch, transection of the DRL resulted in a mean increased 3-dimensional translation of 1.3 mm, whereas transection of the dAOL resulted in a mean increased 3-dimensional translation of 0.6 mm. Statistically significant 2-dimensional findings in lateral pinch after transecting the DRL or dAOL included an increased palmar subluxation of 0.3 mm and 0.2 mm, an increased radial (1.0 mm) and ulnar (0.3 mm) translation, and an increased pronation of 4.1 degrees and 2.4 degrees, respectively. In thumb opposition, transection of the DRL resulted in a mean increased 3-dimensional translation of 1.0 mm, whereas transection of the dAOL resulted in a mean increased 3-dimensional translation of 0.5 mm. CONCLUSIONS: In most degrees of freedom of metacarpal movement relative to the trapezium, the DRL is relatively more important than the dAOL in providing stability to the TMC joint.

Anatomy of the coronoid process.

PURPOSE: Coronoid injuries are classified according to the size of the coronoid fracture. The purpose of this study was to provide a detailed anatomic description of the coronoid process, with specific focus on the coronoid height, the coronoid width, and the olecranon-coronoid angle. METHODS: Thirty-five cadaveric arms were dissected. All soft tissue was removed and the ulna was disarticulated from the humerus, radius, and the carpal bones. A 3-dimensional digitizing system was used to locate 19 anatomic landmarks on each specimen. By using the 3-dimensional coordinates of the landmarks, the coronoid heights, proximal ulnar widths, and olecranon-coronoid angles were determined. RESULTS: The coronoid height, with its base defined by the trough of the trochlear notch and the slope change of the distal coronoid process, measured 15 mm and was 42% of the ulnar height. The coronoid height, with its base defined by the transverse groove of the sigmoid notch at the guiding ridge and the distal insertion of the brachialis muscle, measured 15 mm and was 43% of the ulnar height. The olecranon-coronoid angle ranged between 33 degrees and 38 degrees . CONCLUSIONS: For lateral radiographic classification of coronoid fractures, coronoid height is best defined by the trough of the trochlear notch and the slope change of the distal coronoid process. For anatomic studies, coronoid height is best defined by the transverse groove of the sigmoid notch at the guiding ridge and the distal insertion of the brachialis muscle. The olecranon-coronoid angle is best defined by the angle formed by the lines from the olecranon tip through the coronoid tip and through the slope change of the distal coronoid process. The coronoid anatomy measurements reported in this study may help to improve coronoid fracture classification.

Repair of zone II flexor digitorum profundus lacerations using varying suture sizes: a comparative biomechanical study.

PURPOSE: To compare the maximum tensile load, change in work of flexion, and gapping at the repair site after zone II flexor digitorum profundus tendon repairs using 2-0, 3-0, and 4-0 braided polyester 4-strand locked cruciate repair technique in fresh-frozen cadaveric hands with standard 6-0 suture epitenon repairs, to determine which suture size is the best for a core repair. METHODS: A randomized study was designed using 41 tendons from 15 fresh-frozen cadaveric hands. We included only the flexor digitorum profundus tendons from the index, middle, and ring fingers to minimize variation between digits. Core suture size was randomized for each finger. A sharp laceration through the flexor digitorum profundus in zone II was made and a 4-strand locked cruciate braided polyester core stitch was performed along with a locked epitenon stitch. Cyclic loading was performed for 1,000 cycles. For each tendon the mean work of flexion (before/after zone II repair) and maximum tensile load were measured using a custom-designed tensiometer, as was gapping before maximum tensile loading. RESULTS: Mean gaps after 1,000 load-unload cycles to 3.9 N of pulp pinch did not approach the clinically significant limit of 3 mm in each group. By using a regression model, we found that the prerepair and postrepair comparisons for mean work of flexion to a 3.9-N pulp pinch showed the greatest change in work of flexion for 2-0 braided polyester. Statistical significance was found between 2-0 braided polyester and 3-0 or 4-0 braided polyester; however, the work of flexion between the 3-0 and 4-0 polyester was not clinically significant. The highest maximum tensile load was obtained with suture size 2-0 braided polyester. The maximal tensile load statistically showed 2-0 braided polyester to be stronger than 4-0 braided polyester but we found no statistically significant difference between 3-0 and 2-0 braided polyester or between 3-0 and 4-0 braided polyester. CONCLUSIONS: In this cadaveric study we found that increasing locking cruciate suture caliber from 4-0 to 2-0 increased maximum tensile strength but also caused increased work of flexion. Gapping was not affected by suture caliber. There was no significant difference in strength or mean change in work of flexion between 3-0 or 4-0 braided polyester sutures.

Zone I flexor tendon injuries.

Zone I flexor tendon injuries entail injuries to the flexor digitorum profundus (FDP) tendon. These injuries occur distal to the superficialis insertion over the middle phalanx or proximal distal phalanx, and as such are isolated injuries to the FDP. The mechanism most commonly is closed avulsion from the distal phalanx or a laceration, but other mechanisms such as open avulsion or crush injury can occur. On physical examination, the cascade of the fingers will be disrupted, and distal interphalangeal (DIP) joint flexion must be isolated to determine if the FDP tendon is continuous, as other mechanisms are present to enable finger flexion at the other joints.

Acute flexor tendon repairs in zone II.

Flexor tendon repair in zone II is still a technically demanding procedure, but the outcomes have become more predictable and satisfying. Of keystone importance for obtaining the goals of normal strength and gliding of repaired flexor tendons are an atraumatic surgical technique, an appropriate suture material, a competent pulley system, and the use of early motion rehabilitation protocols. The overall goal of hand and finger function also implies timely addressing of neurovascular injuries. New devices such as the TenoFix (Ortheon Medical; Winter Park, Florida) have shown adequate strength in the laboratory but are bulky and untested for work of flexion. Insufficient clinical data and high cost may prevent widespread use.

The future of flexor tendon surgery.

Clinical outcomes following flexor tendon repair have made significant improvements in the last 50 years. In that time standard treatment has evolved from secondary grafting to primary repair with postoperative rehabilitation protocols. Unfortunately, excellent results are not yet attained universally following treatment. Improving understanding of tendon healing at the cellular, molecular, and genetic levels will likely enable surgeons to modulate the normal repair process. We now look toward biologic augmentation of flexor tendon repairs to address the problems of increasing tensile strength while reducing adhesion formation following injury and operative repair.

Characterization of adenovirus-mediated gene transfer in rabbit flexor tendons.

PURPOSE: Adenoviral vector-based gene therapy is a promising technique for the delivery of growth factors to tendons. The objective of this study was to determine whether rabbit flexor tendons could be transduced effectively by adenoviral vectors and whether the introduction of adenoviral vectors would cause a notable local inflammatory response. METHODS: Recombinant adenoviruses expressing green fluorescent protein (AdGFP) or BMP-13 (AdBMP-13) were constructed and 3 different viral titers (1 x 10(7), 1 x 10(8), and 1 x 10(9)) were tested in this study. The second through fifth tendons of the forepaws and hindpaws of a New Zealand white rabbit were identified surgically and injected with different viral titers of adenoviruses. The fifth tendon was used as a control. The tendons were harvested 12 days after surgery. The retrieved tendons were sectioned to measure transgene expression, as well as for histologic evaluation. RESULTS: At all tested viral titers an efficient dose-dependent transgene expression was detected in all samples at 12 days after injection. At the highest dose the injection sites were notable for lymphocytic infiltration, suggesting that injected adenoviral vectors can illicit some local inflammatory response. Lymphocytic infiltration was much less apparent, however, in the tendons injected with lower titers of adenoviral vectors. There was no evidence of a massive inflammatory response and/or cell death. CONCLUSIONS: Our findings show that adenovirus-based gene therapy is an efficient means of gene delivery to rabbit flexor tendons. Transduction efficiency of transgenes was dose dependent across the tested titers, although adenovirus-induced inflammation was notable only at the highest titer. This indicates that efficient gene transfer without notable local inflammatory response may be achieved by using the lower titers. Although adenovirus-induced inflammation can be minimized by using lower viral titers, its impact on adhesion formation in the long term remains unknown.

Effects of the adductor pollicis and abductor pollicis brevis on thumb metacarpophalangeal joint laxity before and after ulnar collateral ligament reconstruction.

PURPOSE: The intrinsic muscles and ulnar capsuloligamentous structures (UCLS), which consist of the ulnar collateral ligament (UCL), accessory UCL, dorsal capsule, and volar plate of the thumb metacarpophalangeal (MCP) joint are important for controlling the motion and stability of the MCP joint during pinch. The purpose of this cadaveric study was to determine the effects of the adductor pollicis (AdP) and abductor pollicis brevis (APB) on the 3-dimensional MCP joint laxity before transection of the UCLS and after reconstruction of the UCL and repair of the dorsal capsule. METHODS: Loads were applied to the flexor pollicis longus (FPL) alone, to the AdP and FPL in combination, and to the APB and FPL in combination in 11 cadavers. This was done in the intact joint after the UCLS were transected and after the UCL was reconstructed for flexion angles of 0 degrees, 15 degrees, 30 degrees, and 45 degrees. The spatial positions of the proximal phalanx and the metacarpal of the MCP joint were measured with a 6-degrees-of-freedom digitizing system. RESULTS: In the intact joint combined loading of the AdP and FPL did not affect the position of the proximal phalanx. Combined loading of the APB and FPL changed the position of the phalanx from an ulnar to a radial shift and from an ulnar to a radial deviation and it increased pronation. After transection of the UCLS combined loading of the FPL and AdP increased supination of the MCP joint and combined loading of the FPL and APB increased radial shift, radial deviation, and pronation of the joint. Reconstruction of the UCL restored normal laxity to the MCP joint. CONCLUSIONS: The AdP failed to affect MCP joint motion. The ABP produced a radial shift and radial deviation of the MCP joint and increased pronation of the thumb. Transection of the UCLS increased joint laxity for each of the combined loadings and reconstruction of the UCL restored normal laxity to the MCP joint.

The strength of distal fixation of flexor digitorum profundus tendon grafts in human cadavers.

Early active motion limits adhesion formation and thus improves functional performance after tendon grafting. The early strength of distal fixation is critical to successful tendon grafting. We describe a new Y-tunnel technique of distal fixation and compare it with 2 established methods, the Pulvertaft transverse tunnel and the Bunnell button over the fingernail techniques, in a human cadaver model to determine which is the strongest method. Hands with a grafted tendon were rigidly mounted on an anatomic tensiometer testing apparatus and loaded to failure. Mean load to failure (newtons +/- 95% confidence intervals) of the Y-tunnel technique (155.2 +/- 29.4) was greater than those for the Pulvertaft (100.2 +/- 13.2) and Bunnell (57.1 +/- 4.7) techniques. Two-way analysis of variance showed significant differences, and the Bonferroni multiple pairwise comparison test showed that all 3 intergroup comparisons were statistically significant. These results indicate marked improvement in immediate strength with the Y-tunnel technique and lay the groundwork for further studies using a healing tendon model.

Comparative biomechanical performances of 4-strand core suture repairs for zone II flexor tendon lacerations.

To compare the biomechanical performances of six 4-strand flexor tendon repairs at zone II, we used an in situ testing model in 54 cadaver profundus tendons. The techniques studied were the modified Becker, modified double Tsuge, Lee, locked cruciate, Robertson, and Strickland. Prerepair and postrepair comparisons for work of flexion to a 3.9-N pulp pinch (equal to 12.6 N tendon force) showed the greatest interference to gliding in the modified Becker repair and the least in the modified double Tsuge repair. Mean gaps after 1,000 load-unload cycles to a 3.9-N pulp pinch did not approach the clinically important limit of 3 mm in all groups. Ultimate tensile strength was highest in the modified Becker (69.4 +/- 8.2 N) but not significantly higher than the modified double Tsuge (60.3 +/-15.3 N) and locked cruciate (64.1 +/- 16.2 N). In all repair groups the mean pulp pinch forces upon failure were well above values recommended for active mobilization protocols that use external load guides. The locked cruciate, modified double Tsuge, and modified Becker repairs were strong enough for an early active motion protocol after surgery. Locked cruciate and modified double Tsuge were easier to perform and provided less interference to tendon gliding than the modified Becker repair.