Biomechanical comparison of techniques to reduce the bulk of lacerated flexor tendon ends within digital sheaths of the porcine forelimb.

PURPOSE: Zone II flexor tendon repairs may create a bulging effect with increased bulk and resistance to tendon gliding. A biomechanical time 0 study was performed to assess 2 methods of tendon antibulking for work of flexion and strength characteristics. METHODS: We placed 24 fresh-frozen porcine forelimb tendons in a custom jig. Deep flexor tendon was sectioned just distal to the intact A1 and A2 pulleys. Specimens were divided into 3 groups before repair: group 1, nonmodified tendon; group 2, 30 degrees bilateral notch excised from both tendon ends; and group 3, triangular longitudinal central wedge excised from both tendon ends. All repairs used a 4-strand modified Kessler core suture and running circumferential epitendinous suture. Work of flexion, 2-mm gap formation, and ultimate load to failure were tested. RESULTS: Both antibulking techniques (groups 2 and 3) had significantly less work of flexion than group 1 (36.3 and 34.9 J vs 142.9 J, p < .001). There was no significant change in work of flexion between groups 2 and 3 (p > .05). There was no significant difference in terms of 2-mm gap formation among the 3 groups (p > .05). Groups 1 and 3 exhibited a significantly higher load to failure compared with group 2 (p < .05). CONCLUSIONS: The antibulking repair techniques used in this study decrease the work of flexion with no significant change in force to 2-mm gap formation. Group 2, however, did have significantly lower load to failure. These techniques might be beneficial in zone II flexor tendon injury, in which the tight annular pulley system restricts tendon gliding. However, this is a time 0 study and the potential adverse effects of increase tendon manipulation and trauma were not analyzed, which might increase adhesions and scar during the healing phase of tendon repair.

Defective monocyte function in patients with genitourinary carcinoma.

An assay allowing quantitation of monocyte function, i.e., chemotaxis, was used to study the activity of monocytes in patients with neoplasms of the urinary tract. Twenty-four subjects with various stages of renal carcinoma exhibited a mean chemotactic defect of 34% (P less than 0.005) as compared to normal controls and patients hospitalized with nonneoplastic diseases. Twelve persons with transitional cell carcinoma of the bladder had a 29.8% (P less than 0.01) mean chemotactic defect as compared to the controls. There was no correlation between tumor stage and degree of chemotactic defect;--J Natl Cancer Inst 55: 1047-1054, 1975.

Outcome of arthroscopic reduction association of the scapholunate joint.

This study evaluates the arthroscopic reduction association scapholunate technique and outcomes. A total of 18 patients with chronic scapholunate instability with mean follow-up of 36 months were reviewed. Postoperatively, the mean visual analogue score was 2.5 and the mean DASH score was 8. The grip strength was 27 kg on the operative side compared with 32 kg on the uninjured side. The mean wrist flexion was 46° and extension was 56°. Seven patients had complications. Six patients had scapholunate joint widening, one had windshield-wipering of the screws with loss of reduction, and two demonstrated progression of scapholunate advanced collapse deformity. Four patients underwent revision surgeries: two revision arthroscopic reduction association scapholunates and two proximal row carpectomies. A preoperative scapholunate gap of greater than 5 mm and the presence of scapholunate advanced collapse Grade I were both predictive of a complication or revision surgery. Patients with a scapholunate gap of greater than 5 mm or scapholunate advanced collapse had statistically higher complications rates.Level of Evidence IV.

Prevention of fracture healing in rats by an inhibitor of angiogenesis.

Angiogenesis is considered essential to fracture healing, but its role in the healing process remains poorly understood. Angiogenesis inhibitors, which block new blood vessel formation by specifically targeting vascular cells, are currently under development for use in cancer chemotherapy, and are potentially powerful tools for defining the consequences of angiogenic impairment on fracture healing. In this study, we directly tested the effects of the angiogenesis inhibitor TNP-470 on the healing of closed femoral fractures in an established rat model system. Beginning 1 day after fracture, animals received either angiogenesis inhibitor at a therapeutically effective antitumor dose, or a weight-adjusted amount of carrier vehicle. The progress of fracture healing was assessed at weekly intervals for 21 days by radiography and histology; functional assessment was carried out at day 24 by biomechanical testing. By all three criteria, treatment with the angiogenesis inhibitor completely prevented fracture healing. Formation of both callus and periosteal woven bone were suppressed, indicating that both the intramembranous and endochondral pathways of osteogenesis were affected. The resulting tissue resembled "atrophic nonunions" often seen clinically in cases of failed fracture healing, but rarely achieved in animal models. These results show that angiogenesis is essential to very early stages of fracture healing, and suggest this model system may be useful for understanding the mechanisms underlying fracture nonunions due to vascular impairment. Finally, the data raise the possibility that impairment of fracture healing may be an adverse effect of clinical treatments with antiangiogenic drugs.

The cellular basis of Wolff's law. Transduction of physical stimuli to skeletal adaptation.

The cellular milieu responsible for skeletal homeostasis is extremely complex, comprised of many elements, and serves to accomplish both structural and metabolic responsibilities. From one perspective, it is the interactions of the cells loosely grouped as "osteoregulatory" which must retain many of the mineral and metabolic levels of the body. From another view, the coordinated formation and resorption of mineralized tissues, relegated by this same population of cells, is predominantly responsible for achieving and retaining the structural integrity of the skeleton. Unfortunately, the predominant focus of much research is asympathetic to the multifaceted role of the skeleton; it is perceived either as a mineral reservoir or as a structural entity. The skeleton, however, is both of these things. It is not until we acknowledge the dual responsibility of bone that we will be able to understand what parameters, systemic or local, control its regulation. Considered within the context of a three-dimensional movie, with metabolic roles cast in red and structural ones in green, neither the impact nor depth of the film can be appreciated until viewed through the glasses which consider the intricate balance between both the mechanical and mineral dimensions.

Treatment of urinary infections with cefadroxil: controlled comparison of high-compliance oral dosage regimens.

The efficacy and tolerability of cefadroxil were assessed in a controlled comparison of high-compliance oral dosage regimens among 100 patients with urinary tract infections. Each patient was randomly assigned to one of three cefadroxil treatment groups: 2,000 mg. once daily, 1,000 mg. once daily, or 1,000 mg. twice daily. Urine cultures at five to nine days post-treatment revealed cures in 27 of 36 patients in the 2,000-mg. daily group, 32 of 36 patients in the 1,000-mg. daily group, and 27 of 28 patients taking 1,000 mg. twice daily. Recurrence rates were extremely low in all treatment groups, and only 3 patients had evidence of limited side effects. The benefits of a convenient and readily understood dosage schedule are discussed.

Chemotherapy-induced alterations in the biomechanics of rat bone.

The effects of methotrexate and doxorubicin (Adriamycin) on intact and fractured bone were studied in a rat model. Methotrexate, 0.1 mg/kg i.p., was administered five times a week, or doxorubicin, 1 mg/kg i.v., was given once a week. Animals were killed and evaluated at 4, 8, 12, and 16 weeks after surgical production of a unilateral femoral osteotomy and initiation of the chemotherapeutic program. Both intact and fractured bones were tested to failure in rapid torsion, and the torque, angular deformation, stiffness, and energy were measured. There was a significant alteration in the strength of the healing osteotomies in doxorubicin- and methotrexate-treated animals compared with the control group. The torsional strength of intact bone was not significantly altered by either drug protocol over the period of this observation.

Ballistics and gunshot wounds: effects on musculoskeletal tissues.

As a result of the increasing number of weapons in this country, as many as 500,000 missile wounds occur annually, resulting in 50,000 deaths, significant morbidity, and striking socioeconomic costs. Wounds are generally classified as low-velocity (less than 2,000 ft/sec) or high-velocity (more than 2,000 ft/sec). However, these terms can be misleading; more important than velocity is the efficiency of energy transfer, which is dependent on the physical characteristics of the projectile, as well as kinetic energy, stability, entrance profile and path traveled through the body, and the biologic characteristics of the tissues injured. Although bullets are not sterilized on discharge, most low-velocity gunshot wounds can be safely treated nonoperatively with local wound care and outpatient management. Typically, associated fractures are treated according to accepted protocols for each area of injury. Treatment of low-velocity, low-energy fractures is generally dictated by the osseous injuries, as these are similar in many regards to closed fractures. Soft tissues play a more critical role in high-velocity and shotgun fractures, which are essentially open injuries. Aside from perioperative prophylaxis, antibiotics are probably required only for grossly contaminated wounds; however, because contamination is not always apparent, most authors still recommend routine prophylaxis. High-energy injuries and grossly contaminated wounds mandate aggressive irrigation and debridement, including a thorough search for foreign material. Open fracture protocols including external fixation or intramedullary nailing and intravenous antibiotic therapy for 48 to 72 hours should be instituted. If there is vascular damage, exploration and repair are best performed after prompt fracture stabilization. Evaluation of the "four Cs"-color, consistency, contractility, and capacity to bleed-provides valuable information regarding the viability of muscle. Skin grafting is preferable when tension is required for wound closure, although other soft-tissue procedures, such as use of local rotation flaps or free tissue transfer, may be necessary, especially for shotgun wounds. Distal neurologic deficit alone is not an indication for exploration, as it often resolves without surgical intervention.

Microvascular applications in limb sparing tumor surgery.

New techniques in microvascular tissue transfer make it possible to "add" bone, muscle, and skin to deficient areas and to maintain and restore function. Clearly, a price is paid, but careful evaluation and judicious weighing of the costs and benefits can vastly expand our reconstructive capabilities. Furthermore, as our knowledge of microvascular anatomy expands, new donor sites with particular attributes and less donor site morbidity are constantly being described. The profusion of new procedures and techniques over the last decade is, perhaps, unparalleled in any surgical specialty. Such techniques not only extend our definitions of what is "salvageable," but also refine our conception of what is functionally or cosmetically acceptable. This enables us not only to extend the indications for limb sparing surgery, but also to move beyond merely "salvaging" extremities to reconstructing functional, cosmetically appealing limbs. These are, to be sure, arduous, complicated cases requiring considerable planning and commitment on the part of the surgeon and the patient, but a successful outcome is extremely gratifying to both parties.

Hand infections.

The diagnosis and treatment of common hand infections are reviewed. A practical approach to the treatment of these conditions is detailed. This approach emphasizes the anatomic compartments of the hand, the microbiology of infecting organisms, and the patient conditions which modify treatment. Prompt and accurate diagnosis, treatment, and rehabilitation are key for optimal outcome.

Gunshot wounds to the shoulder.

The proximity of vascular, neural, osseous, and muscular structures make gunshot wounds to the shoulder area particularly challenging. This review focuses on the epidemiology, pathophysiology, diagnosis, and treatment of these injuries. Special attention is given to the usefulness of vascular and electrodiagnostic studies.

The role of microvascular surgery in limb-sparing procedures for malignant tumors of the knee.

Limb-sparing surgery has proven to be a feasible alternative to amputation for treatment of malignant tumors about the knee. Microvascular surgery and the possibility of providing healthy, stable soft-tissue coverage to the affected limb have expanded the possible role of limb-sparing techniques. Microvascular free flaps were utilized in 26 patients undergoing resection for large malignant tumors of the knee or adjacent to the knee. Patients were then followed for a minimum of 3 years to a maximum of 7 years and evaluated for tumor recurrence and limb function. Survival and disease-free interval were 68 and 77 percent, respectively, in stage II patients and only 50 and 0 percent, respectively, in stage III patients. Function, as determined by the MSTS functional evaluation system, was found to be fair to good in all patients. Microvascular free-tissue transfer has proven to be a valuable adjunct in limb-sparing surgery.

Balloon assisted endoscopic harvest of the latissimus dorsi muscle.

In this study, we present our experience with balloon assisted endoscopic harvest of the latissimus dorsi muscle for extremity reconstruction. The balloon performs most of the dissection under the muscle and creates the optical work space used in the endoscopic dissection. Over the course of this series the operative time has been reduced and averaged 2 hours and 44 minutes. The reconstructive goals were met in all cases. The average axillary incision length was 5.6 cm, and there were an average of 1.3 one-centimeter or smaller counter incisions.

Improved left ventricular function in myocardial infarction following intravenous thrombolytic therapy with acylated plasminogen activator.

Forty-six patients with acute myocardial infarction (MI) were treated within three hours of the onset of chest pain with an intravenous bolus (IV) of 30 units of anisolated plasminogen activator streptokinase complex (APSAC). Reperfusion was detected in 31 patients (67%) by clinical, electrocardiographic, and enzymatic criteria. The mean time elapsed between the onset of the chest pain to thrombolytic therapy was 114 +/- 53 minutes. Left ventricular ejection fraction (LVEF) was significantly better in patients with anterior and inferior myocardial infarction who had successful reperfusion, as compared with those who did not (48.8 +/- 13.0 vs 35.3 +/- 10.9, p less than 0.05 and 59.7 +/- 12.6 vs 47.9 +/- 15.3, p less than 0.05, respectively). The rate of reocclusion within three weeks was 22%. The overall one-year mortality was 4%. There were no serious adverse reactions following the thrombolytic treatment. Thus bolus IV injection of 30 units of APSAC is both safe and effective in preserving left ventricular function when given early in the course of acute myocardial infarction.

Percutaneous Freehand system intramuscular electrode placement.

The FreeHand (NeuroControl Corporation, USA) system is an implantable electronic neuroprosthesis designed to stimulate muscles of tetraplegic upper limbs to achieve lateral pinch and simple grasp. When first introduced, the system required insertion through multiple large incisions, but recently introduced intramuscular electrodes have allowed the development of a percutaneous electrode placement technique. The technique minimizes incisions, decreases overall operative time and patient morbidity and improves the outcome by minimizing tendon adhesions.

The distal radioulnar joint.

A phylogenic review shows the DRUJ to be a highly evolved and specialized structure. The diarthrodial joint, in combination with the TFCC, ligament complex, and oblique fibers of the distal interosseous membrane, permit rotation while preserving stability and transmitting the load borne by the radiocarpal joint to both bones of the forearm. Our improved, yet imperfect, understanding of the anatomy, biomechanics, and pathophysiology of the region, abetted by new imaging modalities and wrist arthroscopy, permit more precise diagnosis and thus more rational treatment. The persistent inconsistency of our results belies our imperfect comprehension. Thus humbled, consider Goethe's admonition as a call to further scrutiny and investigation, "Theory and experience are opposed to each other in constant conflict. Only action can reconcile them."

Microvascular techniques in limb-sparing surgery.

Microvascular techniques allowing free tissue transfer have expanded the indications for limb salvage in tumor patients. Preoperative planning should predict the type of deficit anticipated. Specific techniques for soft tissue, skeletal, neurovascular, and composite tissue transfer are discussed. While demanding, the use of living autogenous tissue gives the potential for biologic adaptivity and life-long durability.