bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Significance of Molds Newly Available for Radioallergosorbent Testing
Authors: King William P.
Published: July 2017

Three years of weekly Rotorod airborne allergen reports from Corpus Christi, Texas, were reviewed. Five of 10 newly available airborne molds for radioallergosorbent testing (RAST) were present in significant numbers. Three hundred seventy‐five mold RAST evaluations were expanded to include the five old and these five new molds. Except for Alternaria, the frequency of and allegenic response to the new molds were generally greater than those for the five old molds. The usual Alternaria‐Cladosporium mold screen proved less satisfactory when these five new molds were added to the mold battery; however, the addition of Helminthosporium to the screen corrected this deficiency. Cross‐reactivity production of false‐positive responses seems unlikely because of frequent significant variance in RAST scores from mold to mold in the same patient.
Pediatric Cochlear Implantation: Strategies to Accommodate for Head Growth
Authors: Marks David R. , Jackler Robert K. , Bates Grant J. , Greenberg Sheldon
Published: July 2017

Accommodation for head growth presents one of several challenges unique to pediatric cochlear implantation. Given contemporary cochlear implant device designs, an electrode cable implanted at the age of 2 years must extend 2 to 3 cm as the head grows during childhood. In an initial study we found that model lead wires with redundant loops extended effectively when they were maintained within air‐containing spaces such as the mastoid cavity or middle ear space. However, when looped leads traversed soft tissues overlying the parietal bone, they became embedded in fibrous tissue and did not extend. The present study evaluated three different configurations of expansile devices that were enclosed In polytetrafluoroethylene (PTFE) envelopes to deter fibrous ingrowth. This simple strategy was designed to ensure effective cable extension over cable pathlengths by protecting the redundant leads from any mechanically significant connective tissue ingrowth. Twelve such devices were implanted across the calvaria of four newly weaned plglets. Skull growth and changes in electrode dimensions were documented by sequential computed tomographic scans. At 3 months of age, cranial circumferences had increased substantially. Animals were then killed, the model cable extension appliances examined physically, and their implantation sites examined histologically. For all experimental devices, extension of redundant lead wires was satisfactory, and there was no mechanically significant invasion of fibrous connective tissue into the PTFE envelope. This indicates that enclosure of excess lead wire within a PTFE envelope may be an effective means of inhibiting fibrous Ingrowth. This strategy should prove useful for ensuring effective electrode cable extension In cochlear implants applied in young children.
Cerebral Shift after Lateral Craniofacial Resection and Flap Reconstruction
Authors: Haughey Bruce H. , Gates George A. , Skerhut Holger E. , Brown Willis E.
Published: July 2017

The biomechanical effects on the cranial contents after craniectomy and immediate soft‐tissue flop reconstruction are substantial and potentially life threatening. Once the rigid protective covering of the skull is removed, the cerebral component of the cranial contents is vulnerable to rising extrinsic pressure. Intracranial pressure falls, brain compliance rises, and contralateral cerebral shift may occur by virtue of the craniectomy alone. However, if flaps filling the defect should compress by weight or swelling, even greater midline or craniocaudal shift of the brain may occur. We present three cases in which midline cerebral shift was documented by CT scan after flop reconstruction oflateralcraniofacial/cranlotemporal resection. Three other patients undergoing anterior craniofacial resection during the same time period for skin cancer (one patient) and esthesioneuroblastoma (two patients) had no shift in intracerebral contents. Symptomatic or asymptomatic intracranial shift may occur soon after substantial craniectomy and soft‐tissue flap reconstruction. Midline shift from lateral resection and reconstruction is more likely than anteroposterior shift from anterior craniofacial resection. Strategies for minimizing this compression or shift are described.
Lesions of Rathke's Duct: Another Indication for the Infratemporal Fossa Approach
Authors: Herzog Jacques , Makek Miro , Fisch Ugo
Published: July 2017

Rathke's duct is a midline structure, arising from the primitive stomodeum and extending upward to the hypophysis. The duct, which normally involutes in utero, may persist on occasion. This most frequently results in intracranial disease. Occasionally, disease may become manifest in the extracranial skull base. We present three such cases: Cystic craniopharyngioma, Rathke's cleft cyst, and a persistent cerebrospinal fluid rhinorrhea caused by a patent craniopharyngeal canal. Each lesion involved the clivus and the parasphenold region. Surgical management of such lesions requires not only extirpation of disease, but also the ability to recognize and preserve the many important regional structures. The procedure that best allows for the wide exposure necessary to accomplish these goals is the infratemporal fossa approach to the lateral skull base.
Blindness and Intranasal Endoscopic Ethmoidectomy: Prevention and Management
Authors: Stankiewicz James A.
Published: July 2017

Blindness is one of the major complications that can occur during and after Intranasal ethmoidectomy. Two mechanisms for blindness are apparent: (1) direct injury to the optic nerve and (2) retrobulbar (orbital) hematoma, which incresaes orbital pressure and compromises vascular supply and drainage to and from the eye. While several publications have discussed the management of blindness from a delayed operative vantage point, no publication has discussed the immediate management of blindness from intraoperative or immediate postoperative occurrence, stressing specific medical and surgical treatment. A review of the literature and the author's personal experience will be used as a basis to discuss the prevention and management of blindness during endoscopic Intranasal ethmoidectomy. Case studies will be used to Illustrate methods for prevention and management of blindness. If treated aggressively, blindness associated with retrobulbar hematoma can be reversed medically.
Squamous Cell Carcinoma of the External Auditory Meatus (Canal)
Authors: Arriaga Moises , Hirsch Barry E. , Kamerer Donald B. , Myers Eugene N.
Published: July 2017

A retrospective study of 35 patients with squamous cell carcinoma of the external auditory meatus treated at the Eye and Ear Hospital of the University of Pittsburgh was performed. The standard treatment was a temporal bone resection that corresponded to the extent of the lesion, followed by postoperative radiation therapy. The tumor extensions, symptoms, treatments, survival rates, and prognostic variables were reviewed. Overall, 12 of 35 patients survived. Lesions limited to the external auditory meatus with no erosion had excellent prognoses. Survival in intermediate lesions with bony erosion or middle ear Involvement was related to the status of surgical margins after partial or subtotal temporal bone resections. Extensive lesions that involved the surrounding soft tissue or dura had poor prognoses. The survival value of total temporal bone resection remains unproved.
Efficacy of Alternative Tests for Delayed‐Cyclic Food Hypersensitivity
Authors: King William P. , Rubin Wallace , Fadal Richard G. , Ward Walter A. , Trevino Richard J. , Pierce William B. , Stewart Alan , Boyles John H.
Published: July 2017

With the oral challenge food test (OCFT) used as the standard for delayed‐cyclic food hypersensitivity diagnosis, blinded comparison studies were accomplished with 175 in vitro food specific IgE and 180 IgG radioallergosorbent tests, 180 food enzyme‐linked immune complex assays, and 155 in vivo Multi‐Test prick tests. The study was multi‐centered, eight physicians and 37 patients participating. All of the compared tests were shown to be approximately 50% efficient when compared with the OCFT results, and, thus, nonefficaclous.
The Osteo‐Mucoperiosteal Flap in Repair of Cerebrospinal Fluid Rhinorrhea: A 20‐Year Experience
Authors: Yessenow Randall S. , McCabe Brian F.
Published: July 2017

Chronic cerebrospinal fluid rhinorrhea (present for 2 months or longer) is a serious condition frequently encountered by the otolaryngologist–head and neck surgeon. The purpose of this report is that it can be successfully repaired transanally, from below, with a high rate of success. Intracranial repair has been associated with reportedly high morbidity and failure rates. From 1967 to 1987, 16 patients underwent repair of chronic cerebrospinal fluid rhinorrhea in the cribriform plate or fovea ethmoidalis at the University of Iowa with an osteomucoperiosteal flap. Follow‐up data from 1.6 to 22 years demonstrated no recurrent leaks in this group of patients. Minimal morbidity and no deaths were associated with the osteomucoperiosteal flap. On the basis of our experience, we recommend this technique, which can be performed by any experienced paranasal sinus surgeon, as superior to craniotomy for the repair of chronic cerebrospinal fluid rhinorrhea from cribriform plate and fovea ethmoidalis defects.
Adipose Plug Myringoplasty: An Alternative to Formal Myringoplasty Techniques in Children
Authors: Gross Charles W. , Bassila Mahan , Lazar Rande H. , Long Thomas E. , Stagner Shirley
Published: July 2017

Adipose myringoplasty is presented as a simple and cost‐effective technique in managing small tympanic membrane perforations in children. A review of 76 fat plug myringoplasties performed on 62 children with drum perforations over a 15‐year period was done. Fifty‐nine myringoplasties were postinflammatory and/or after extrusion of pressure‐equalizing (PE) tubes. Sixteen were residual perforations following temporalis fascia tympanoplasty, and one was posttraumatic perforation. Criteria for selection, operative technique, and results are discussed.
The Surgical Management of Advanced Malignancies of the Parotid Gland
Authors: Katsantonis George P. , Friedman William H. , Rosenblum Barry N.
Published: July 2017

Advanced malignancies of the parotid gland frequently Invade the parapharyngeal space and the Infratemporal fossa. The majority of these lesions have not been cured by surgery and/or radiotherapy, and palliation or cure can only be achieved by en bloc resection of this region. Stylohamular dissection is a systematic method for en bloc resection of the Infratemporal fossa and lateral skull base. From January 1980 until December 1987, 18 patients with advanced parotid malignancies underwent stylohamular dissection. Pathologic examination revealed the following diagnosis: Adenocarcinoma (7), squamous cell carcinoma (5), high‐grade mucoepidermoid carcinoma (2), metastatic adenocarcinoma (1), fibrosarcoma (1), malignant hemangiopericytoma (1), and melanoma (1). Nine patients In this series are alive after a mean follow‐up period of 3.5 years (range 1 to 9 years). Three patients are dead of uncontrolled local disease and three of distant metastasis. Three patients died of unrelated causes. All patients except the three who had uncontrolled disease experienced marked palliation from their pain, trismus, and unmanageable ulcerative lesions after surgery. The operative morbidity was relatively low.
Effect of Lipoteichoic Acid on Proliferation and Differentiation of Keratinocytes
Authors: Yabe Takeshi , Huang Cheng‐Chun
Published: July 2017

Bacterial infection is always found to be associated with cholesteatoma. Accumulation of keratin debris is one of the crucial factors for the growth of cholesteatoma. The effects of lipoteichoic acid, a cell wall component of gram‐positive bacteria, on the proliferation and differentiation of keratinocytes were studied. Various concentrations of lipoteichoic acid (0 to 100 μg/ml) were added to keratinocytes. DNA synthesis and protein synthesis were inhibited by decreasing the incorporation of 3H‐thymldine and 3H‐leucine into keratinocytes. The effects of lipoteichoic acid on terminal differentiation were then studied by measuring the number of sodium dodecyi sulfate‐Insoluble cornlfied cell envelopes and the transglutaminase activity (a marker of terminal differentiation) determined by incorporation of 3H‐putrescine into cornifled envelopes. These studies showed that lipoteichoic acid stimulated the formation of cornifled cell envelopes and transglutaminase activity. These findings suggest that lipoteichoic acid stimulated the terminal differentiation and accumulation of keratin debris and that lipoteichoic acid might have stimulatory effects on the development of cholesteatoma.
Evaluation of Eighth Nerve Integrity by the Electrically Evoked Middle Latency Response
Authors: Jyung Robert W. , Miller Josef M. , Cannon Stephen C.
Published: July 2017

A reliable objective test for estimating the number and distribution of surviving eighth nerve fibers needs to be identified for selection of candidates for cochlear Implantation. Kanamycin and ethacrynic acid administration In guinea pigs resulted In graded amounts of eighth nerve degeneration over time. The electrically‐induced middle latency response (EMLR) was acutely recorded in these animals at specific post‐drug times, followed by the immediate killing of the animals, histologic preparation, and spiral ganglion cell density determination. Significant progressive spiral ganglion cell loss was noted by 4 weeks that Increased over time. While EMLR threshold remained stable over time, the slope of the EMLR Input/output function decreased with Increasing post‐drug intervals in a manner directly correlated with reduction in spiral ganglion cell density.
The Feedback Lecture: An Illustration
Authors: Gottko John , Osterman Dean
Published: July 2017

While very popular in U.S. academic institutions, the lecture method suffers from a number of problems, most of which center around the lack of student involvement. The feedback lecture addresses this issue while satisfying both faculty and students. This article presents a case example and a discussion of the applicability of the feedback lecture.
Pathogenesis of Digestive Tract Lesions in Duck Plague
Authors: Proctor S. J.
Published: July 2017

White Pekin ducklings were inoculated orally with duck plague virus. Tissues from the digestive tract were collected daily after inoculation and examined by light, electron and fluorescent microscopy. There were necrosis and degeneration of stratified squamous epithelium of the esophagus and cloaca, epithelium of intestinal crypt and esophageal submucosal glands, macrophages in the lamina propria, and submucosal fibrocytes and lymphocytes. Submucosal hemorrhages occurred after degeneration and necrosis of lymphocytes, macrophages, fibrocytes and epithelial cells. Viral antigens were detected in all these cells by use of fluorescein-labeled antibodies. With the electron microscope, nucleocapsids were seen in the nuclei, budding through the inner nuclear membrane; enveloped virions were present in cytoplasmic vacuoles of macrophages, epithelial cells and fibrocytes. In lymphocytes, nucleocapsids were also in the nuclei, but karyorrhexis and cytolysis occurred before viral maturation was completed.
Mouse Encephalitis Induced by Avirulent Semliki Forest Virus
Authors: Chew-Lim May
Published: July 2017

Encephalitis caused by avirulent Semliki Forest virus was studied at regular intervals for 6 weeks in experimentally infected mice. The most obvious lesion was perivascular cuffing. Microglia were predominant near the vessels early in the infection. The cells of the cuffs were mostly lymphocytes. Although the virus produced acute encephalitis, which gradually resolved by 6 weeks, at no time were there abnormal neurological clinical signs. The cells of the brain and the immune response reacted to eliminate the virus.
Age-Dependent Resistance to Transmissible Gastroenteritis of Swine: III. Effects of Epithelial Cell Kinetics on Coronavirus Production and on Atrophy of Intestinal Villi
Authors: Moon H. W. , Kemeny L. J. , Lambert G. , Stark S. L. , Booth G. D.
Published: July 2017

Coronavirus titers in small intestine, degree of villous atrophy and apparent rates of regeneration of intestinal villi were compared in newborn, 3-week-old and adult pigs for 1 week after they were exposed to the transmissible gastroenteritis virus of swine. The response within the newborn group was homogeneous, resulting in high virus titers, maximal villous atrophy and comparatively slow regeneration. In general, virus titers were lower, villous atrophy was less severe and regeneration more rapid in both older groups than in the newborn pigs. However, the response varied greatly in the older groups. The 3-week-old group was divided into two populations. The major population had low virus titers and developed partial villous atrophy, whereas the minor population had marked villous atrophy and virus titers comparable to those of the newborn pigs. These observations support the hypothesis that the accelerated replacement of villous epithelium in the small intestine of pigs during the first 3 weeks contributes to the innate age-dependent resistance to transmissible gastroenteritis. The accelerated replacement of villous epithelial cells in older pigs contributes to resistance in two ways. The increased proliferative capacity of crypt epithelium results in a more rapid regeneration of atrophic villi; and the comparatively young villous absorptive cells resulting from accelerated replacement produce less virus per cell than the older ones of the newborn pig.
Heavy Metal Nephropathy of Rodents
Authors: Payne B. J. , Saunders L. Z.
Published: July 2017

Heavy metal nephropathy is a pathologic entity of the renal tubular epithelium of rats, evoked by lead, gold, and other heavy metals. It is characterized acutely by coagulative necrosis, subacutely by cortical fibrosis, and chronically by cytomegaly and karyomegaly. Finally, adenomas develop, some of which become malignant.
Spontaneous Mesangioproliferative Glomerulonephritis in Pigtailed Macaques (Macaca nemestrina)
Authors: Boyce J. T. , Giddens W. E. , Seifert R.
Published: July 2017

Mesangioproliferative glomerulonephritis was found in 28 of 113 pigtailed macaques (Macaca nemestrina) that died in 1977. In five it was considered severe enough to cause significant renal dysfunction; in two of these it was the cause of death. The basic lesion was a proliferation of mesangial cells and deposition of mesangial matrix in the mesangial stalk, resulting in various degrees of stalk expansion and increased lobulation of the glomerular tuft. Preliminary immunofluorescence and ultrastructural studies suggest the pathogenesis of the lesion may involve deposition of antigen-IgM immune complexes in the mesangial region.
The Magnetic Resonance Imaging Appearance of Individual Structures of the Posterolateral Knee
Authors: LaPrade Robert F. , Gilbert Thomas J. , Bollom Timothy S. , Wentorf Fred , Chaljub Gregory
Published: July 2017

The purpose of this study was to contrast the magnetic resonance imaging appearance of uninjured components of the posterolateral knee with that of injured structures, and to assess the accuracy of magnetic resonance imaging in identifying posterolateral knee complex injuries. Thin-slice coronal oblique T1-weighted images through the entire fibular head were used to identify the posterolateral structures in seven uninjured knees. The appearance of corresponding grade III injuries to these structures was identified prospectively in 20 patients and verified at the time of surgical reconstruction. The sensitivity, specificity, and accuracy of imaging for the most frequently injured posterolateral knee structures in this series were as follows: iliotibial band-deep layer (91.7%, 100%, and 95%), short head of the biceps femoris-direct arm (81.3%, 100%, and 85%), short head of the biceps femoris-anterior arm (92.9%, 100%, and 95%), midthird lateral capsular ligament-meniscotibial (93.8%, 100%, and 95%), fibular collateral ligament (94.4%, 100%, and 95%), popliteus origin on femur (93.3%, 80%, and 90%), popliteofibular ligament (68.8%, 66.7%, and 68%), and the fabellofibular ligament (85.7%, 85.7%, and 85.7%). Magnetic resonance imaging of the knee was accurate in the identification of these injuries.
Preoperative Sizing of Meniscal Allografts in Meniscus Transplantation
Authors: Shaffer Benjamin , Kennedy Stuart , Klimkiewicz John , Yao Lawrence
Published: July 2017

The purpose of this study was to determine the accuracy of radiographic and magnetic resonance imaging techniques in preoperative sizing for allograft meniscus transplantation. Twelve cadaveric knee specimens underwent sequential radiographs, magnetic resonance imaging scans, and arthrotomy. Meniscus dimensions were measured in multiple planes for the purpose of determining accuracy of imaging studies in comparison with actual meniscus dimensions. Overall, magnetic resonance imaging proved only slightly more accurate than conventional radiography. The mean difference between magnetic resonance imaging measurements and actual meniscus dimensions was 2.25 2.04 mm. The mean difference between radiographic measurements and actual meniscus dimensions was 2.35 1.79 mm. Neither imaging technique was accurate for measuring individual meniscus dimensions, with only 35% of images measuring within 2 mm of actual meniscus dimensions. Using less stringent criteria for accuracy (within 5 mm), radiography and magnetic resonance imaging were 79% and 83% reliable, respectively. Failure to obtain true anteroposterior or lateral images (15° of external and internal rotation) increased measurement inaccuracy. Intraobserver agreement was significantly higher for magnetic resonance imaging than for radiography. Further research into the development of alternative techniques for more reliable meniscus sizing and better understanding of the tolerance for meniscus size mismatch is necessary.
A Novel Suture Anchor of High-Density Collagen Compared with a Metallic Anchor
Authors: Harrison John A. , Wallace Donald , Van Sickle David , Martin Thomas , Sonnabend David H. , Walsh William R.
Published: July 2017

We report the early mechanical properties and histologic findings of a high-density, type I collagen bone anchor. This new anchor was compared with a traditional metallic anchor in a sheep patellar tendon model. No difference in strength of the repair was noted between the two devices at any time point. The insertions on the repaired side approached the strength of the nonoperated side by 12 weeks. Histologic analysis showed that the collagen anchor integrated with the surrounding bone by 6 weeks, and there was little degradation at 12 weeks. The high-density collagen anchor supported tendon healing to bone comparable with that seen with a traditional metallic device, but it has the potential advantage of the anchor being incorporated into bone.
The Proliferative Response of Isolated Human Tendon Fibroblasts to Cyclic Biaxial Mechanical Strain
Authors: Zeichen Johannes , van Griensven Martijn , Bosch Ulrich
Published: July 2017

At the cellular level, dynamic strain plays a key role in cell stimulation and organization of the extracellular matrix. Although positive effects of physical strain on tendon tissue are well known, little knowledge exists on how mechanical strain affects tendon cells. In this study, human tendon fibroblasts from patellar tendon were cultured on silicone dishes. Subsequently, cyclic biaxial mechanical strain was applied to the dishes for 15, 30, and 60 minutes using a specially developed cell stretching system. After the fibroblasts were strained, cells were tested for proliferation at 6, 12, and 24 hours. As a control, cells were grown on silicone dishes but did not receive any strain. A biphasic response in proliferation was observed for the 15- and 60-minute strain periods: at 6 hours and 24 hours there was more proliferation than at 12 hours. After a strain duration time of 30 minutes, a lower proliferation rate was measured compared with control levels. This study shows that application of mechanical stress to tendon fibroblasts resulted in an alteration of cellular proliferation depending on the stress time. Our results may implicate future modifications in the treatment of ligament and tendon injuries.
A Comparison of Ultrasonic Suture Welding and Traditional Knot Tying
Authors: Richmond John C.
Published: July 2017

The slippage of knots and the technical challenge of tying them securely are potential impediments to certain arthroscopic procedures. Ultrasonic energy delivered at 70 kHz can be used to weld No. 2 polypropylene suture. This method was compared with a traditional knot (surgeon's knot with four alternating half hitches) tied with an open technique to determine whether welding of sutures is comparable, in mechanical properties, to hand-tied knots. Both loops were fashioned around a 0.25-inch mandrel and then tested. The load to reach 3-mm elongation (point of likely biologic failure of a repair) was significantly greater for welded sutures than for knots. The elongation at ultimate failure was significantly less for welded sutures than for knots. The number of cycles to failure and the creep after initial displacement were similar for both welded and knotted suture loops. The ultimate load to failure was significantly greater for the knotted than for the welded suture. The welding of suture for the repair of musculoskeletal soft tissue presents an attractive alternative to traditional knot tying, particularly for arthroscopic applications.
Augmentation of Tendon Healing in an Intraarticular Bone Tunnel with Use of a Bone Growth Factor
Authors: Anderson Kyle , Seneviratne Aruna M. , Izawa Kazutaka , Atkinson Brent L. , Potter Hollis G. , Rodeo Scott A.
Published: July 2017

We hypothesized that an exogenous bone growth factor could augment healing of a tendon graft in a bone tunnel in a rabbit anterior cruciate ligament-reconstruction model. Seventy rabbits underwent bilateral anterior cruciate ligament reconstructions with a semitendinosus tendon graft. One limb received a collagen sponge carrier vehicle containing a mixture of bone-derived proteins while the contralateral limb was treated with either no sponge or a sponge without bone-derived proteins. The reconstruction was evaluated at 2, 4, or 8 weeks with histologic, biomechanical, and magnetic resonance imaging analysis. Histologic analysis demonstrated that specimens treated with bone-derived proteins had a more consistent, dense interface tissue and closer apposition of new bone to the graft, with occasional formation of a fibrocartilaginous interface, when compared with control specimens. The treated specimens had significantly higher load-to-failure rates than did control specimens. Treatment with bone-derived proteins resulted in an average increase in tensile strength of 65%. The treated specimens were stronger than control specimens at each time point, but the difference was greatest at 8 weeks. On the basis of signal characteristics and new bone formation, magnetic resonance imaging was useful for predicting which limb was treated, the site of failure, and the limbs with higher load-to-failure values. This study demonstrates the potential for augmenting tendon healing in an intraarticular bone tunnel using an osteoinductive growth factor.
Matrix Assessment of the Articular Cartilage Surface after Chondroplasty with the Holmium:Yttrium-Aluminum-Garnet Laser
Authors: Lane John G. , Amiel Michael E. , Greenfield Richard , Amiel David
Published: July 2017

A long-term in vivo study was performed to assess biochemical changes after laser repair of articular cartilage. Forty New Zealand White rabbits were sacrificed 26 weeks after undergoing an articular cartilage chondroplasty with use of a holmium:yttrium-aluminum-garnet laser at 0.8 joules per pulse and a rate of 10 Hz. Glycosaminoglycan content in the repaired tissue decreased significantly with both perpendicular (19.59 ± 5.6 μg hexosamin/mg of dry tissue) and tangential delivery (14.78 ± 4.5 μg/mg) compared with the sham-treated tissue (39.6 ± 5.0 μg/mg). Cellular viability was also significantly decreased. Sulfate incorporation was decreased to 203 ± 142 cpm/mg of dry cartilage in the tangential mode and 461 ± 209 cpm/mg in the tangential mode, compared with the sham at 1845 cpm/mg. Uptake of [3H]thymidine decreased to 463 ± 473 cpm/mg of dry tissue and 455 ± 170 cpm/mg in the tangential and perpendicular modes, respectively, compared with 2465 cpm/mg in the sham tissue. There were no significant differences between the tangential and perpendicular delivery modes in any assessments performed. The short-term chondrocyte destruction previously noted in a 12-week study after laser treatment was not reversed during a longer-term 26-week study, and cellular viability was not recovered, suggesting that the loss of chondrocyte function may be permanent.
Relationship of Ulnar Collateral Ligament Strain to Amount of Medial Olecranon Osteotomy
Authors: Andrews James R. , Heggland Erik J. H. , Fleisig Glenn S. , Zheng Nigel
Published: July 2017

Athletes at risk for valgus extension overload are also at risk for tears of the anterior bundle of the ulnar collateral ligament. Some athletes develop ligament tears after procedures for valgus extension overload such as posteromedial olecranon osteotomy. The amount of posteromedial olecranon that can be resected before ulnar collateral ligament strain, and risk of injury, increases is unknown. We dissected and mounted five fresh-frozen human cadaveric elbows to allow strain gauge monitoring of the ulnar collateral ligament with varying valgus stress, elbow flexion angle, and medial osteotomy. The average strain to failure was 11.96% ± 6.51%, corresponding to a load of 347.71 ± 46.42 N. The maximum tensile force recorded at failure was 416.24 N. Three-way repeated-measures analysis of variance revealed no significant change in strain with change in the amount of osteotomy for a given applied load and angle of flexion. On the basis of these data, we conclude that the effect of medial olecranon osteotomy on ulnar collateral ligament strain may be small. Small sample size, elderly specimens, and the variables inherent in the experimental setup and mathematical modeling make it difficult to extrapolate these results to in vivo behavior of the anterior ulnar collateral ligament. Further work is needed before definitive guidelines for olecranon osteotomy can be formulated.
Biomechanical Analysis of the Effect of Varying Suture Pitch in Tendon Graft Fixation
Authors: Jassem Muhammed , Rose Alexander T. , Meister Keith , Indelicato Peter A. , Wheeler Donna
Published: July 2017

The purpose of this study was to biomechanically assess the effect of varying suture pitch on the holding power of the Krackow suture technique for tendon graft fixation. Seven pairs of rabbit Achilles tendons were sutured with single No. 5 Ti-Cron suture using the Krackow technique. One tendon from each pair was sutured using a 0.5-cm suture pitch (half-pitch group) while the contralateral tendon from each pair was sutured with a 1.0-cm suture pitch (one-pitch group). The tendons were loaded to failure using a servohydraulic materials test system at a loading rate of 0.5 mm/sec. There were no statistically significant differences noted in suture slippage at failure (1.58 cm for half pitch versus 1.45 cm for one pitch) or maximal force to failure (158.5 N for half pitch versus 168.2 N one pitch) between the two treatment groups. However, the construct with the 1-cm suture pitch was significantly stiffer than the construct with the 0.5-cm suture pitch, with stiffness values of 106.2 N/cm and 91.4 N/cm, respectively. The most common mechanism of failure was slippage of the suture at the first suture throw and tearing of the first knot through the most distal portion of the tendon. Four constructs failed by suture rupture, two from each experimental group.
Motion Loss after Ligament Injuries to the Knee
Authors: Millett Peter J. , Wickiewicz Thomas L. , Warren Russell F.
Published: July 2017

This is the second part of a two-part review on motion problems after ligament injuries to the knee. The first part, published in the September/October 2001 issue, discussed normal and abnormal knee motion, terminology, risk factors, and pathoanatomy. The purpose of this article is to review current concepts on prevention and treatment of motion problems, summarizing the recent and pertinent studies that discuss this complicated clinical problem. The first part of this article will discuss the different classification schemes that have been published on motion loss of the knee. Prevention strategies will be discussed next, followed by early recognition. Finally, a discussion of the various treatment options and published results will be presented in detail, together with the authors’ nine-step systematic surgical approach to the stiff knee.
Kinematics and Laxity of the Knee Joint after Anterior Cruciate Ligament Reconstruction
Authors: Brandsson Sveinbjörn , Karlsson Jon , Swärd Leif , Kartus Jüri , Eriksson Bengt I. , Kärrholm Johan
Published: July 2017

Background

Injury of the anterior cruciate ligament changes the kinematics of the knee joint. In studies of cadaveric knees, investigators have examined the effect of anterior cruciate ligament reconstruction on knee kinematics, but the effect on dynamic knee motion is not known.

Hypothesis

Reconstruction of the anterior cruciate ligament restores knee kinematics to normal.

Study Design

Prospective cohort study.

Methods

Nine patients were examined preoperatively and 1 year after reconstruction. Continuous radiostereometric exposures were performed at a speed of two to four exposures per second while the patients ascended an 8-cm high platform. Tibial rotation and tibial and femoral translation were measured with radiostereometric analysis.

Results

Tibial rotation and tibial and femoral translation were not significantly different after anterior cruciate ligament reconstruction compared with preoperative measurements. A radiostereometric evaluation of anterior knee laxity revealed restoration to within 1 mm of that on the uninjured side. Further evaluation of knee function using the Lysholm score, the Tegner activity level score, the International Knee Documentation Committee evaluation system score, and measurements of laxity using the KT-1000 arthrometer revealed significant improvements after reconstruction.

Conclusion

Kinematics of the anterior cruciate ligament injured knee did not change significantly after ligament reconstruction, but the functional results were satisfactory and knee laxity was diminished.
The Most Effective Exercise for Strengthening the Supraspinatus Muscle
Authors: Takeda Yoshitsugu , Kashiwaguchi Shinji , Endo Kenji , Matsuura Tetsuya , Sasa Takahiro
Published: July 2017

Background

Electromyography has been used to determine the best exercise for strengthening the supraspinatus muscle, but conflicting results have been reported. Magnetic resonance imaging T2 relaxation time appears to be more accurate in determining muscle activation.

Purpose

To determine the best exercises for strengthening the supraspinatus muscle.

Study Design

Criterion standard.

Methods

Six male volunteers performed three exercises: the empty can, the full can, and horizontal abduction. Immediately before and after each exercise, magnetic resonance imaging examinations were performed and changes in relaxation time for the subscapularis, supraspinatus, infraspinatus, teres minor, and deltoid muscles were recorded.

Results

The supraspinatus muscle had the greatest change among the studied muscles in relaxation time for the empty can (10.5 ms) and full can (10.5 ms) exercises. After the horizontal abduction exercise the change in relaxation time for the supraspinatus muscle (3.6 ms) was significantly smaller than that for the posterior deltoid muscle (11.5 ms) and not significantly different from that of the other muscles studied.

Conclusion

The empty can and full can exercises were most effective in activating the supraspinatus muscle.
Evidence of Abnormal Anteroposterior Patellar Tilt in Patients with Patellar Tendinitis with Use of a New Radiographic Measurement
Authors: Tyler Timothy F. , Hershman Elliott B. , Nicholas Stephen J. , Berg Jeffery H. , McHugh Malachy P.
Published: July 2017

Background

A number of clinical conditions of the patellofemoral joint have been correlated with abnormal patellofemoral radiographic measurements.

Hypothesis

An abnormal anteroposterior patellar-tilt angle may be a contributing factor to pathologic conditions of the knee.

Study Design

Prospective nonrandomized clinical trial.

Methods

The anteroposterior patellar-tilt angle was measured in cadaveric knees to determine the best knee position. The radiographs of normal subjects and patients with patellar tendinitis or patellofemoral pain syndrome were examined for differences in patellar-tilt angle.

Results

Cadaveric measurements demonstrated highest intertester and intratester reliability at 30° of knee flexion and neutral femoral rotation. Intratester measurements on normal subjects exhibited high reliability, with a mean anteroposterior tilt angle of 30.8° ± 6.7°. In the patellofemoral pain group the mean anteroposterior tilt angle was 29.1° ± 8.5°; however, for patients with patellar tendinitis, it was 25.6° ± 7.0°, significantly lower than in the normal population. Furthermore, there was no difference between the angles of involved and uninvolved knees of patients with unilateral patellar tendinitis.

Conclusion

The anteroposterior patellar-tilt angle is a clinically reliable measurement of patellar tilt in the sagittal plane that can be used to study patellofemoral tilt in a variety of clinical situations. The results of this study demonstrate that patients with patellar tendinitis have abnormal patellar tilt in the sagittal plane.
Arthroscopic Findings in Patients with Chronic Ankle Instability
Authors: Hintermann Beat , Boss Andreas , Schäfer Dirk
Published: July 2017

Background

There are little objective data on structural changes of the chronically unstable ankle. Such knowledge could help with preoperative planning.

Hypothesis

Preoperative ankle arthroscopy provides important insights into the causes and mechanisms of ankle instability and the resulting disability.

Study Design

Case series.

Methods

From 1993 to 1999, arthroscopic examination was performed in the ankles of 148 patients with symptomatic chronic ankle instability that had lasted 6 months or more. All structural changes were recorded and compared with the clinical diagnosis.

Results

A rupture or elongation of the anterior talofibular ligament was noted in 86% of ankles, of the calcaneofibular ligament in 64%, and of the deltoid ligament in 40%. Cartilage damage was noted in 66% of ankles with lateral ligament injuries, whereas 98% of the ankles with deltoid ligament injuries had cartilage damage. Although lateral instability could be verified arthroscopically in 127 patients, medial instability was presumed clinically in 38 patients but was actually detected in 54 patients arthroscopically.

Conclusion

Preoperative ankle arthroscopy revealed an essential amount of information that would otherwise have been undetected. For instance, the ligaments showed typical abnormalities corresponding to different entities of ankle instability and different intra-articular pathologic conditions.
Supplementation of Rotator Cuff Repair with a Bioresorbable Scaffold
Authors: Koh Jason L. , Szomor Zoltan , Murrell George A. C. , Warren Russell F.
Published: July 2017

Background

Repair of a torn rotator cuff should have sufficient initial strength of the fixation to permit appropriate rehabilitation.

Hypothesis

Augmentation with a woven polylactic acid scaffold strengthens repairs of the rotator cuff.

Study Design

Controlled laboratory study.

Methods

In the suture-anchor model, 10 pairs of sheep infraspinatus tendons were detached and repaired to suture anchors. In half of the matched specimens, the repair was reinforced with a woven poly-lactic acid scaffold repaired with the tendon to bone. In the bone-bridge model, sutures were passed through a trough and over a bone bridge distal to the greater tuberosity; half were reinforced by the scaffold. The repairs were tested to failure with a hydraulic testing machine.

Results

The mean ultimate strength of suture-anchor repairs augmented with the scaffold (167.3 ± 53.9 N) was significantly greater than that of nonaugmented fixation (133.2 ± 38.2 N). Failure occurred when the tendon pulled through the sutures; the scaffold remained intact. Scaffold reinforcement of the bone bridge significantly increased the ultimate strength from 374.6 ± 117.6 N to 480.9 ± 89.2 N, and the scaffold remained intact in 8 of 10 specimens.

Conclusions

The scaffold significantly increased the initial strength of rotator cuff repair by approximately 25%.
Reduction of Medial Compartment Loads with Valgus Bracing of the Osteoarthritic Knee
Authors: Pollo Fabian E. , Otis James C. , Backus Sherry I. , Warren Russell F. , Wickiewicz Thomas L.
Published: July 2017

Background

Patients with medial compartment osteoarthritis of the knee may be treated nonoperatively with adjustable valgus bracing.

Hypothesis

Valgus bracing reduces load on the medial compartment through the application of an external valgus moment about the knee, resulting in pain relief.

Study Design

Prospective cohort study.

Methods

Eleven patients were tested using an instrumented brace and three-dimensional gait analysis. We measured the valgus moment applied by the adjustable valgus brace and determined the compressive load in the medial compartment. We also documented the effects of increased valgus alignment of the brace and increased strap tension on load sharing. Pain and activity levels were also recorded.

Results

Pain and activity level improved in all subjects with valgus bracing. During gait, valgus bracing reduced the net varus moment about the knee by an average of 13% (7.1 N•m) and the medial compartment load at the knee by an average of 11% (114 N) in the calibrated 4° valgus brace setting. Increasing valgus alignment with the adjustable brace had a greater effect on the medial compartment load than did increasing strap tension.

Conclusion

Adjustable valgus bracing was effective in reducing medial compartment load and subsequent pain while also improving knee function in a group of patients with osteoarthritis.
Avulsion Fracture of the Ulnar Sublime Tubercle in Overhead Throwing Athletes
Authors: Salvo John P. , Rizio Louis , Zvijac John E. , Uribe John W. , Hechtman Keith S.
Published: July 2017

Background

Injuries to the ulnar collateral ligament are relatively common in throwing athletes and result from either acute traumatic or repeated valgus stress to the elbow. Avulsion fracture of the sublime tubercle of the ulna is a rarely reported site of ulnar collateral ligament injury.

Purpose

We retrospectively reviewed our cases of ulnar collateral ligament injuries to study avulsion fractures of the sublime tubercle of the ulna.

Study Design

Case series.

Methods

Data, including radiographs and magnetic resonance imaging scans, were obtained by review of hospital and office records and by follow-up examination. Of 33 consecutive patients treated for ulnar collateral ligament injuries, 8 had avulsion fractures of the sublime tubercle of the ulna. All eight were male baseball players with dominant arm involvement, an average age of 16.9 years, and an average follow-up of 23.6 months.

Results

Six of eight patients had failure of nonoperative treatment and required surgical repair. Two of the six underwent ulnar collateral ligament reconstruction and four had direct repair of the sublime tubercle avulsion with bioabsorbable suture anchors. At last follow-up, all eight had returned to their preinjury level of activity. No patient had residual medial elbow pain or laxity.

Conclusions

Diagnosis of sublime tubercle avulsion fracture is made with history, physical examination, and radiographic studies. Magnetic resonance imaging can help identify an avulsion fracture not visible radio-graphically and can help determine whether direct repair or reconstruction is needed.
Surgical Repair of Distal Biceps Tendon Ruptures
Authors: Pereira David S. , Kvitne Ronald S. , Liang Michael , Giacobetti Frank B. , Ebramzadeh Edward
Published: July 2017

Background

Rupture of the distal biceps brachii tendon has most commonly been repaired by anatomic reattachment of the tendon to the radial tuberosity by a single- or two-incision approach. Researchers have studied suture anchor attachment through a single incision, but the tendon-suture interface and bone quality have not previously been analyzed.

Hypothesis

Suture anchor repair results in stiffness and tensile strength equal to that of bone-tunnel repair for biceps tendon rupture.

Study Design

Controlled laboratory study.

Methods

Twelve matched pairs of fresh-frozen cadaveric elbow specimens were used. Suture anchor and bone-tunnel tendon repairs were performed in a randomized fashion. Each specimen was loaded to tensile failure. Load-displacement graphs were generated to calculate repair stiffness, yield strength, and ultimate strength. Computed tomography bone density measurements and additional statistical analyses were then performed after grouping the specimens by mode of failure.

Results

The bone-tunnel repair was found to be significantly stiffer in all cases and to have significantly greater tensile strength than the suture anchor repair in the younger, nonosteoporotic elbows.

Conclusions

Suture anchor repairs were not as stiff or strong as bone-tunnel repairs.

Clinical Relevance

Biceps tendon surgery using the traditional two-incision technique yields a stronger and stiffer repair in the typical patient with this injury.
Diagnosis and Treatment of Patients with Patellofemoral Pain
Authors: Fulkerson John P.
Published: July 2017

The patient-athlete with patellofemoral pain requires precise physical examination based on a thorough history. The nature of injury and specific physical findings, including detailed examination of the retinacular structure around the patella, will most accurately pinpoint the specific source of anterior knee pain or instability. Radiographs should include a standard 30° to 45° axial view of the patellae and a precise lateral radiograph. Nonoperative treatment is effective in most patients. Prone quadriceps muscle stretches, balanced strengthening, proprioceptive training, hip external rotator strengthening, patellar taping, orthotic devices, and effective bracing will help most patients avoid surgery. When surgery becomes necessary, indications must be specific. Lateral release is appropriate for patella tilt (abnormal rotation). Painful scar or retinaculum, neuromas, and pathologic plicae may require resection. Proximal patellar realignment may be accomplished using arthroscopic or a combined arthroscopic/mini-open approach. Symptomatic articular lesions and more profound malalignments may require medial or anteromedial tibial tubercle transfer. Clinicians should be particularly alert for symptoms of medial subluxation in postoperative patients and should use the provocative medial subluxation test followed by lateral displacement patellar bracing to confirm a diagnosis of medial patellar subluxation. This problem may be corrected in most patients using a lateral patellar tenodesis. Current thinking emphasizes precise diagnosis, rehabilitation involving the entire kinetic chain, restoration of patella homeostasis, minimal surgical intervention, and precise indications for more definitive corrective surgery.