Incidence of acromioclavicular joint complications after arthroscopic subacromial decompression.

We performed a chart and radiograph review of 173 patients (183 shoulders) who underwent arthroscopic subacromial decompression between 1991 and 1994 and had preoperative and postoperative radiographs. The study focused on the presence of preoperative acromioclavicular joint pathology, intraoperative violation of the acromioclavicular joint, extent of distal clavicle excision, and subsequent development of acromioclavicular joint symptoms. The 183 surgical procedures were divided into three groups: shoulders with subacromial decompression without acromioclavicular joint violation (103 of 183; 56%; group A); shoulders with subacromial decompression with acromioclavicular joint violation and partial distal clavicle resection (36 of 183; 20%; group B); and shoulders with subacromial decompression with complete distal clavicle resection (44 of 183; 24%; group C). Groups A and C had no postoperative sequelae in reference to the acromioclavicular joint. In contrast, 14 of the 36 shoulders (39%) in group B with a documented acromioclavicular joint violation and a partial distal clavicle resection developed acromioclavicular joint symptoms at an average of 8.4 months (range, 1.8 to 19 months) after surgery. This finding was statistically significant (P=.0001). The results of this study suggest that any violation of the acromioclavicular joint in the course of an arthroscopic subacromial decompression may jeopardize the result. The degree of violation is not helpful in predicting outcome. As a result of this study, we suggest an all-or-none surgical approach to the acromioclavicular joint and distal clavicle resection.

Functional distal interphalangeal joint splinting for trigger finger in laborers: a review and cadaver investigation.

This two-part study evaluates the efficacy of functional distal interphalangeal joint (DIP) splinting for the treatment of trigger finger. Thirty-one fingers from 21 meat packing plant workers were treated with DIP splinting. A single corticosteroid injection was offered if triggering was stage 4 or greater. All workers returned to work immediately. Eighty-one percent of the digits were treated successfully (mean follow-up: 1 year). Treatment failure correlated with duration of symptoms and stage of triggering but did not correlate with age, race, sex, disease in multiple digits, or prior treatment. For the second part of the study, the effect of DIP splinting on flexor digitorum profundus (FDP) tendon excursion was studied in 16 fingers from 4 fresh cadavers. Excursion decreased 4.8 mm for the Stax splint and 4.2 mm for the dorsal Alumafoam splint. We conclude that DIP splinting provides a reliable and functional means of treating work-related trigger finger without lost time from work. Our cadaver investigation supports our theory that DIP splinting significantly decreases FDP excursion.

Captured shoulder: a complication of rotator cuff surgery.

Thirteen patients who developed restrictive subdeltoid adhesions after rotator cuff repair were identified. These patients underwent second-look arthroscopy and takedown of adhesions at an average of 37 weeks after their index surgery. Clinical findings include pain and restricted motion that does not yield to manipulation under anesthesia. Arthroscopic findings are subdeltoid adhesions and a chondral lesion (companion lesion) of the humeral head articular surface. Patients were reevaluated at 26 weeks after their release of adhesions. Prerelease and postrelease University of California, Los Angeles (UCLA) scores average 14.8 and 30.1, respectively. Prerelease and postrelease UCLA pain scores averaged 2.6 and 7.7, respectively. Prerelease and postrelease range of motion was as follows: Flexion, 141/158; abduction, 123/141; internal rotation, 47/69; and external rotation, 53/74. The authors have proposed a theory to explain the clinical and arthroscopic findings in this subgroup of patients who are dissatisfied after rotator cuff repair. A technique for and the results of release of the subdeltoid adhesions also are reported.

The effect of substrate on the radiation resistance of yeasts isolated from sausage meat.

The radiation resistance of a selection of yeasts isolated from sausages was assessed in phosphate-buffered saline and in sausage meat. The yeasts Candida zeylanoides, Debaryomyces hansenii and Trichosporon cutaneum exhibited sigmoidal survival curves in both substrates whilst the more sensitive Sporobolomyces roseus exhibited an exponential survival curve in buffer but a sigmoidal curve in meat. Irradiating C. zeylanoides, D. hansenii and T. cutaneum in sausage meat changed the shape of their survival curves to significantly alter the calculated parameters Ds (the dose in kGy that must be achieved before reduction in numbers occurs) and D10sig (the dose in kGy required after the shoulder to achieve a 1 log cycle reduction in numbers). The Ds values were reduced while higher D10sig values were obtained demonstrating that the sausage meat contributed a protective effect to these yeasts at higher irradiation doses. For the yeast S. roseus, similar numbers of survivors were recovered from both substrates at initial low irradiation doses (0-0.5 kGy) with the protective effect being demonstrated again at higher doses (> 2 kGy). These findings should be considered when defining a commercial process to reduce the numbers of yeasts in these products.

Early-onset respiratory failure caused by severe congenital neuromuscular disease.

Two unrelated infants with low Apgar scores, pneumothoraces, and severe pulmonary hypertension were treated with extracorporeal membrane oxygenation while receiving chemical sedation and neuromuscular paralysis. After decannulation from extracorporeal membrane oxygenation, hypotonia and hypoventilation persisted. Neurologic evaluation confirmed that both infants had a congenital myopathy.

Comparison of the Septi-Chek AFB and BACTEC systems and conventional culture for recovery of mycobacteria.

The performance of the Septi-Chek AFB system was compared with that of the BACTEC radiometric system and that of Lowenstein-Jensen agar slants (LJ) for detection of mycobacteria in clinical specimens. A total of 642 specimens were cultured; 61 (9.5%) yielded mycobacteria. Mycobacterium tuberculosis (34 isolates) and Mycobacterium avium complex (25 isolates) were the predominant species isolated. Of the 61 culture-positive specimens, 30 were smear positive and 31 were smear negative. Overall, 95% of the positive specimens were detected by Septi-Chek and BACTEC (100% of M. tuberculosis isolates) and 75% by LJ (82% of M. tuberculosis isolates). The mean times to detection were 15 days for BACTEC, 23 days for Septi-Chek, and 27 days for LJ. Of the 30 smear-positive specimens, 100% were recovered by Septi-Chek and BACTEC and 90% were recovered by LJ. Of the 31 smear-negative specimens, 90% were detected by Septi-Chek and BACTEC and 61% were detected by LJ. The Septi-Chek and BACTEC systems are superior to the conventional (LJ) mycobacterial culture method. Although Septi-Chek requires more time for the detection of mycobacteria than BACTEC, it is comparable in terms of overall recovery.

Measurements of length and tension patterns during reconstruction of the posterior cruciate ligament.

The twofold purpose of this study was to develop an intraoperative technique to assess isometric positioning of posterior cruciate ligament grafts and to demonstrate the rationale for postoperative immobilization of the knee in full extension after a posterior cruciate ligament reconstruction. Multiple femoral fixation sites were selected on the medial intercondylar notch and the posterior cruciate ligament substitute was assessed for changes in length and tension at each of these sites during knee flexion from 0 degree to 120 degrees. The most isometric and isotonic femoral fixation site was localized over a small area slightly distal to the center of the medial intercondylar notch surface. This isometric point can be identified intraoperatively using recognizable surface markers within the knee. When a posterior stress was applied to the proximal tibia, the posterior cruciate ligament substitute showed the least increase in tension and length when the knee was locked in full extension for all of the potential femoral attachment sites assessed. This suggests that postoperative immobilization should be maintained in full extension to limit the stress placed on the posterior cruciate ligament reconstruction.

Biomechanical and histologic evaluations of pulley reconstructions in nonhuman primates.

A2 pulleys were reconstructed in nonhuman primates using expanded polytetrafluoroethylene, woven nylon, and fascia. Biomechanical and histologic evaluations were done after death at 18 weeks. Tendons were normal after all pulley reconstructions. Polytetrafluorethylene had a greater breaking strength than woven nylon or fascia, or control pulleys, both at 18 weeks and before implantation. Histologic analyses revealed fibrous ingrowth of host tissues, no adhesions, no trauma to underlying flexor tendons, and the absence of an inflammatory response, for all pulley types.

A nonparallel, nonisometric synthetic graft augmentation of a patellar tendon anterior cruciate ligament reconstruction. A model for assessment of stress shielding.

The potential for a rigidly fixed synthetic graft placed in the over-the-top position to be stress shielding/stress sharing with the patellar tendon autograft was assessed in a primate model. A patellar tendon autograft was placed anatomically and tensioned at 2 pounds for all of the groups. In the augmented animals, a 30 strand braided graft 10 cm in length of expanded polytetrafluoroethylene was tightened with the knee in full extension. After 6 months of unrestricted cage activity the animals were sacrificed and biomechanical testing performed. The augmented patellar tendon autografts demonstrated less laxity in extension as compared to the autografts alone. A minimal decrease in the load and stiffness to failure for the augmented groups as compared to the nonaugmented knees was noted. However, both the reconstruction groups had a significant decrease in the load to failure at 6 months (50% of the normal ACL). In summary, this study demonstrated that a synthetic graft augmentation can be performed in the over-the-top position and minimize knee laxity, especially during terminal extension. With this technique, the laxity was minimized while the incorporation and strengthening of the biologic autograft occurred at a rate similar to the unaugmented reconstruction.

Perfusion of the abductor digiti quinti after transfer on a neurovascular pedicle.

The perfusion to the abductor digiti quinti muscle was measured, both before and after, opponensplasty transfer on its neurovascular pedicle in six monkeys, with use of the hydrogen wash-out technique to determine blood flow. The musculotendinous unit can be transferred without vascular compromise, but detachment of the abductor digiti quinti from its origin on the pisiform results in ischemia. Such impairment of blood flow to the muscle may be responsible for the postoperative fibrosis, which has been seen as a complication of the procedure.

Quantification of the perfusion of the anterior cruciate ligament and the effects of stress and injury to supporting structures.

The perfusion of the normal ACL was quantitated using the hydrogen washout technique in a canine model. This was compared to the perfusion of the synovium in the suprapatellar pouch. Changes in the ACL perfusion were quantitated after the application of anterior stress, division of the infrapatellar fat pad, and dissection of the synovium enveloping the ACL. The ACL is relatively hypovascular, with one-half the blood flow of the synovium of the suprapatellar pouch. Application of an anterior stress diminishes the blood flow to the ACL to one-fifth of the baseline value, an effect which is reversible. Division of the infrapatellar fat pad causes a two-fold decrease in perfusion to the ACL, whereas dissection of the enveloping synovium results in a complete cessation of blood flow.

Flexor tendon pulley reconstructions--a histological and ultrastructural study in non-human primates.

The feasibility of A2 pulley reconstructions using expanded polytetrafluoroethylene (PTFE), woven nylon, and fascia lata was assessed in a non-human primate model and evaluated by light and scanning electron microscopy 18 weeks after implantation. No adhesions were found between reconstructed pulleys and flexor tendons. All types of pulley were intact and incorporated by host tissues, without evidence of a foreign body reaction. The inner surfaces of the fascial and PTFE pulleys, apposed to the gliding flexor tendons, were smooth and covered by a fibrous layer of tissue on microscopic and ultrastructural examination. The apposed visceral synovial surfaces of the F.D.P. tendon were indistinguishable from those from unoperated digits. The FDP tenosynovium apposed to woven nylon pulleys was more fibrillar and granular. Based on the results of the present study and on previous biomechanical data, expanded PTFE should be considered as a material for pulley reconstruction; it is incorporated by host tissues, elicits no foreign body reaction and causes no adhesions or traumatic changes to underlying flexor tendons. It is not yet known whether it has sufficient breaking strength to meet the functional demands of human pulleys.

Use of the Herbert bone screw for scaphoid nonunions.

The Herbert bone screw was used to treat 22 selected patients with established scaphoid nonunions. The indications for its use included evidence of avascular necrosis, proximal third fracture fragment, previous bone graft, fracture angulation or displacement, and a bipartite scaphoid. Treatment resulted in radiographic and clinical evidence of healing in 16 patients; 4 patients were symptom-free, but had incomplete healing as evidenced by radiograph; and 2 patients had persistent symptoms with radiographic evidence of nonunion.

Pathomechanics of posterior sag of the tibia in posterior cruciate deficient knees. An experimental study.

This study was an investigation of the pathomechanics of posterior sag of the tibia in knees with posterior knee instability caused by PCL deficiency. By using fresh cadaver knees, the authors hoped to define the relationship of the posterior joint capsule and the medial and lateral collateral ligaments (MCL, LCL) with posterior knee instability in the PCL deficient knee. Thirty newtons of posterior stress were applied to the knees to simulate postoperative conditions. Roentgenographic methods were then used to evaluate posterior sag and change in the distance between the origin and insertion of the PCL. Strain gauges were used to measure the actual strain of the PCL and the collateral ligaments. The PCL, the posterior capsule, and the medial and lateral collateral ligaments were sequentially divided and the above measurements were then repeated in the same way, using 30 N of applied posterior stress. When only the PCL was cut, posterior sag and medial rotation of the tibia occurred with increasing severity as flexion increased. No sagging or rotation of the tibia was observed at full extension in the knees that had isolated PCL "injury". When the posterior capsule was sectioned, no significant changes were noted in the severity of the sag or the rotation. When the MCL or LCL was divided in a PCL deficient knee, greater sag occurred with flexion and a significant sag was observed even at full extension. The MCL "injury" was associated with increased medial rotation, whereas LCL "injuries" were associated with lateral rotation of the tibia.(ABSTRACT TRUNCATED AT 250 WORDS)

Three-dimensional computed tomographic reconstructions of intracranial meningiomas.

In a series of four patients with intracranial meningiomas, three-dimensional computed tomographic (CT) reconstructions were a useful diagnostic and surgical adjunct. Three-dimensional images are created from standard CT data by a boundary-detecting computer software program. Three-dimensional images of tumor invading or adjacent to the bony calvarium are projected about the x, y, and z axes. Axial and sagittal sections delineate the lesions. The images created allow a surgical view of the meningiomas in three-dimensional space and demonstrate the relationship of these masses to the skull. The use of three-dimensional reconstructions in craniofacial surgery and in neurosurgery is reviewed.