Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Answorth A. Allen is active.

Publication


Featured researches published by Answorth A. Allen.


Journal of Bone and Joint Surgery, American Volume | 1998

Magnetic Resonance Imaging of Articular Cartilage in the Knee. An Evaluation with Use of Fast-spin-echo Imaging*

Hollis G. Potter; James Linklater; Answorth A. Allen; Jo A. Hannafin; Steven B. Haas

The purpose of this study was to demonstrate that specialized magnetic resonance imaging provides an accurate assessment of lesions of the articular cartilage of the knee. Arthroscopy was used as the comparative standard.Eighty-eight patients who had an average age of thirty-eight years were evaluated with magnetic resonance imaging and subsequent arthroscopy because of a suspected meniscal or ligamentous injury. The magnetic resonance imaging was performed with a specialized sequence in the sagittal, coronal, and axial planes. Seven articular surfaces (the patellar facets, the trochlea, the femoral condyles, and the tibial plateaus) were graded prospectively on the magnetic resonance images by two independent readers with use of the 5-point classification system of Outerbridge, which was also used at arthroscopy.Six hundred and sixteen articular surfaces were assessed, and 248 lesions were identified at arthroscopy. Eighty-two surfaces had chondral softening; seventy-five, mild ulceration; fifty-three, deep ulceration, fibrillation, or a flap without exposure of subchondral bone; and thirty-eight, full-thickness wear. To simplify the statistical analysis, grades 0 and 1 were regarded as disease-negative status and grades 2, 3, and 4 were regarded as disease-positive status. When the grades that had been assigned by reader 1 were used for the analysis, magnetic resonance imaging had a sensitivity of 87 per cent (144 of 166), a specificity of 94 per cent (424 of 450), an accuracy of 92 per cent (568 of 616), a positive predictive value of 85 per cent (144 of 170), and a negative predictive value of 95 per cent (424 of 446) for the detection of a chondral lesion. Interobserver variability was minimum, as indicated by a weighted kappa statistic of 0.93 (almost perfect agreement).With use of this readily available modified magnetic resonance imaging sequence, it is possible to assess all articular surfaces of the knee accurately and thereby identify lesions that are amenable to arthroscopic treatment.


Journal of Bone and Joint Surgery, American Volume | 1992

Anatomy, histology, and vascularity of the glenoid labrum. An anatomical study.

Daniel E. Cooper; Steven P. Arnoczky; Stephen J. O'Brien; R F Warren; Edward F. DiCarlo; Answorth A. Allen

We studied the gross, histological, and vascular anatomy of the glenoid labrum in twenty-three fresh-frozen shoulders from cadavera to demonstrate its cross-sectional anatomy, its microvascularity, and its attachments. The superior and anterosuperior portions of the labrum are loosely attached to the glenoid, and the macro-anatomy of those portions is similar to that of the meniscus of the knee. The superior portion of the labrum also consistently inserts directly into the biceps tendon, while its inferior portion is firmly attached to the glenoid rim and appears as a fibrous, immobile extension of the articular cartilage. The arteries supplying the periphery of the glenoid labrum come from the suprascapular, circumflex scapular, and posterior circumflex humeral arteries. In general, the superior and anterosuperior parts of the labrum have less vascularity than do the posterosuperior and inferior parts, and the vascularity is limited to the periphery of the labrum. Vessels supplying the labrum originate from either capsular or periosteal vessels and not from the underlying bone.


Journal of Bone and Joint Surgery, American Volume | 2001

Reliability, Validity, and Responsiveness of Four Knee Outcome Scales for Athletic Patients

Robert G. Marx; Edward C. Jones; Answorth A. Allen; David W. Altchek; Stephen J. O'Brien; Scott A. Rodeo; Riley J. Williams; Russell F. Warren; Thomas L. Wickiewicz

Background: Many patient-based knee-rating scales are available for the evaluation of athletic patients. However, there is little information on the measurement properties of these instruments and therefore no evidence to support the use of one questionnaire rather than another. The goal of the present study was to determine the reliability, validity, and responsiveness of four knee-rating scales commonly used for the evaluation of athletic patients: the Lysholm scale, the subjective components of the Cincinnati knee-rating system, the American Academy of Orthopaedic Surgeons sports knee-rating scale, and the Activities of Daily Living scale of the Knee Outcome Survey. Methods: All patients in the study had a disorder of the knee and were active in sports (a Tegner score of 4 points). Forty-one patients who had a knee disorder that had stabilized and who were not receiving treatment were administered all four questionnaires at baseline and again at a mean of 5.2 days (range, two to fourteen days) later to test reliability. Forty-two patients were administered the scales at baseline and at a minimum of three months after treatment to test responsiveness. The responses of 133 patients at baseline were studied to test construct validity. Results: The reliability was high for all scales, with the intraclass correlation coefficient ranging from 0.88 to 0.95. As for construct validity, the correlations among the knee scales ranged from 0.70 to 0.85 and those between the knee scales and the physical component scale of the Short Form-36 (SF-36) and the patient and clinician severity ratings ranged from 0.59 to 0.77. Responsiveness, measured with the standardized response mean, ranged from 0.8 for the Cincinnati knee-rating system to 1.1 for the Activities of Daily Living scale. Conclusions: All four scales satisfied our criteria for reliability, validity, and responsiveness, and all are acceptable for use in clinical research.


Arthroscopy | 2011

Transtibial versus anteromedial portal reaming in anterior cruciate ligament reconstruction: an anatomic and biomechanical evaluation of surgical technique.

Asheesh Bedi; Volker Musahl; Volker Steuber; Daniel Kendoff; Dan Choi; Answorth A. Allen; Andrew D. Pearle; David W. Altchek

PURPOSE The purpose of this study was to objectively evaluate the anatomic and biomechanical outcomes of anterior cruciate ligament (ACL) reconstruction with transtibial versus anteromedial portal drilling of the femoral tunnel. METHODS Ten human cadaveric knees (5 matched pairs) without ligament injury or pre-existing arthritis underwent ACL reconstruction by either a transtibial or anteromedial portal technique. A medial arthrotomy was created in all cases before reconstruction to determine the center of the native ACL tibial and femoral footprints. A 10-mm tibial tunnel directed toward the center of the tibial footprint was prepared in an identical fashion, starting at the anterior border of the medial collateral ligament in all cases. For transtibial femoral socket preparation (n = 5), a guidewire was placed as close to the center of the femoral footprint as possible. With anteromedial portal reconstruction (n = 5), the guidewire was positioned centrally in the femoral footprint and the tunnel drilled through the medial portal in hyperflexion. An identical graft was fixed and tensioned, and knee stability was assessed with the following standardized examinations: (1) anterior drawer, (2) Lachman, (3) maximal internal rotation at 30°, (4) manual pivot shift, and (5) instrumented pivot shift. Distance from the femoral guidewire to the center of the femoral footprint and dimensions of the tibial tunnel intra-articular aperture were measured for all specimens. Statistical analysis was completed with a repeated-measures analysis of variance and Tukey multiple comparisons test with P ≤ .05 defined as significant. RESULTS The anteromedial portal ACL reconstruction controlled tibial translation significantly more than the transtibial reconstruction with anterior drawer, Lachman, and pivot-shift examinations of knee stability (P ≤ .05). Anteromedial portal ACL reconstruction restored the Lachman and anterior drawer examinations to those of the intact condition and constrained translation with the manual and instrumented pivot-shift examinations more than the native ACL (P ≤ .05). Despite optimal guidewire positioning, the transtibial technique resulted in a mean position 1.94 mm anterior and 3.26 mm superior to the center of the femoral footprint. The guidewire was positioned at the center of the femoral footprint through the anteromedial portal in all cases. The tibial tunnel intra-articular aperture was 38% larger in the anteroposterior dimension with the transtibial versus anteromedial portal technique (mean, 14.9 mm v 10.8 mm; P ≤ .05). CONCLUSIONS The anteromedial portal drilling technique allows for accurate positioning of the femoral socket in the center of the native footprint, resulting in secondary improvement in time-zero control of tibial translation with Lachman and pivot-shift testing compared with conventional transtibial ACL reconstruction. This technique respects the native ACL anatomy but cannot restore it with a single-bundle ACL reconstruction. Eccentric, posterolateral positioning of the guidewire in the tibial tunnel with the transtibial technique results in iatrogenic re-reaming of the tibial tunnel and significant intra-articular aperture expansion. CLINICAL RELEVANCE Anteromedial portal drilling of the femoral socket may allow for improved restoration of anatomy and stability with ACL reconstruction compared with conventional transtibial drilling techniques.


Journal of Bone and Joint Surgery, American Volume | 1996

Arthroscopic Release for Chronic, Refractory Adhesive Capsulitis of the Shoulder*

Jon J.P. Warner; Answorth A. Allen; Paul H. Marks; Patrick Wong

Idiopathic adhesive capsulitis usually responds to gentle physical therapy or, if that fails, to closed manipulation with the patient under anesthesia. In some patients, however, loss of motion may be refractory to either of these treatments and an operative release may be indicated. We are reporting on the technique and results of arthroscopic capsular release as a new alternative for the management of such patients. During a three-year period, we managed twenty-three patients who had idiopathic adhesive capsulitis that had failed to respond to physical therapy or closed manipulation. These patients had an arthroscopic anterior capsular release and received forty-eight hours of intensive physical therapy as inpatients. During the physical therapy, the patients received an interscalene regional analgesic with use of repeated nerve blocks or with a continuous infusion through an interscalene catheter. This was followed by a supervised outpatient physical-therapy program. Six patients also had an arthroscopic acromioplasty for the treatment of impingement. There were no complications related to any of the procedures. At a mean of thirty-nine months (range, twenty-four to sixty-four months) after the arthroscopic procedure, the improvement in the score of Constant and Murley averaged 48 points (range, 13 to 77 points). The mean improvement in motion was 49 degrees (range, 0 to 105 degrees) for flexion; 42 degrees (range, 10 to 80 degrees) and 53 degrees (range, 0 to 100 degrees) for external rotation in adduction and abduction, respectively; and eight spinous-process levels (range, three to fourteen levels) and 33 degrees (range, 30 to 60 degrees) for internal rotation in adduction and abduction, respectively. These gains in motion were all significant (p < 0.01) compared with the preoperative values and were within a mean of 7 degrees of the values for the contralateral, normal shoulder. We concluded that, in patients who have loss of motion that is refractory to closed manipulation, arthroscopic capsular release improves motion reliably with little operative morbidity.


Journal of Bone and Joint Surgery, American Volume | 1997

Arthroscopic Release of Postoperative Capsular Contracture of the Shoulder

Jon J.P. Warner; Answorth A. Allen; Paul H. Marks; Patrick Wong

A loss of motion after an operation on the shoulder often cannot be treated successfully with physical therapy or closed manipulation. Although open release techniques generally improve motion, they involve extensive dissection. We developed a technique of arthroscopic capsular release and applied it in eighteen patients who had postoperative stiffness of the shoulder. The patients were selected for the arthroscopic release technique if a conservative program of physical therapy and an attempted closed manipulation had failed to restore motion and if they had no known extra-articular contractures. Five of the thirteen patients who had had a global loss of shoulder motion had motion restored with the anterior capsular release, and six needed an additional release of the posterior aspect of the capsule—that is, a combined (anterior and posterior) capsular release. The arthroscopic procedure could not be completed in the remaining two patients because of an extra-articular scar involving the subscapularis, but those patients were managed successfully with an open release. As five patients had lost only internal rotation and flexion, they had only a posterior capsular release. For the eleven patients who had had either an anterior or a combined (anterior and posterior) capsular release, the mean improvement in the score of Constant and Murley was 43 points (range, 31 to 62 points) and all improvements in motion were significant (p < 0.01). Flexion improved a mean of 51 degrees (range, 10 to 65 degrees); external rotation in adduction and abduction, 31 degrees (range, 10 to 50 degrees) and 40 degrees (range, 5 to 80 degrees), respectively; and internal rotation in adduction and abduction, six spinous-process levels (range, three to eleven levels) and 41 degrees (range, 20 to 70 degrees), respectively. For the five patients who had an isolated posterior capsular release, the score of Constant and Murley improved a mean of 20 points (range, 5 to 35 points) and the improvements in motion also were significant (p < 0.05 and 0.005). Internal rotation in adduction and abduction improved a mean of four spinous-process levels (range, one to ten levels) and 42 degrees (range, 30 to 60 degrees), respectively. Eight patients had an arthroscopic acromioplasty for concomitant impingement disease. One patient who had had a combined (anterior and posterior) release and one who had had a posterior capsular release continued to have pain because of injury of the articular cartilage from a previous operation. We concluded that arthroscopic capsular release is a reliable method for restoring motion with minimum morbidity in carefully selected patients who have postoperative stiffness of the shoulder. When necessary, it can be converted to an open release.


American Journal of Sports Medicine | 2010

Effect of graft selection on the incidence of postoperative infection in anterior cruciate ligament reconstruction.

Joseph U. Barker; Mark C. Drakos; Travis G. Maak; Russell F. Warren; Riley J. Williams; Answorth A. Allen

Background Knee joint infection is a potentially devastating complication of anterior cruciate ligament (ACL) reconstruction. There is a theoretical increased risk of infection with the use of allograft material. Hypothesis An allograft ACL reconstruction predisposes patients to a higher risk of bacterial infection. Study Design Cohort Study; Level of evidence, 3. Methods All primary ACL reconstructions performed at our institution between January 2002 and December 2006 were reviewed; 3126 total procedures were identified. A retrospective medical record review was performed to determine the incidence of infection, offending organism, time after surgery until presentation, infection treatment, and graft salvage as an outcome of graft choice. Results Of the 3126 ACL reconstructions, 1777 autografts and 1349 allografts were performed. Eighteen infections were identified (0.58%). Infections occurred in 6 of the 1349 allografts (0.44%), 7 of the 1430 bone-patellar tendon-bone (BPTB) autografts (0.49%), and 5 of the 347 hamstring autografts (1.44%). Five grafts were removed because of graft incompetence or loosening: 3 hamstring tendon, 1 BPTB, and 1 allograft. The most common organism isolated was Staphylococcus aureus. Hamstring tendon autograft had an increased incidence of infection compared with both BPTB autograft and allograft (P < .05), with a trend toward a more common need for graft removal (P = .09). Allograft reconstructions were equally likely to have graft salvage as autograft reconstructions. Conclusion Hamstring tendon autografts have a higher incidence of infection than BPTB autografts or allografts. The use of allograft material in ACL reconstructions does not increase the risk of infection or the need for graft removal with infection.


Knee Surgery, Sports Traumatology, Arthroscopy | 1999

Proprioception in the posterior cruciate ligament deficient knee.

Marc R. Safran; Answorth A. Allen; Scott M. Lephart; P. A. Borsa; Freddie H. Fu; Christopher D. Harner

Abstract This study was undertaken to evaluate knee proprioception in patients with isolated unilateral posterior cruciate ligament (PCL) injuries. Eighteen subjects with isolated PCL tears were studied 1–234 months after injury. The threshold to detect passive motion (TTDPM) was used to evaluate kinesthesia and the ability to passively reproduce passive positioning (RPP) to test joint position sense. Two starting positions were tested in all knees: 45 ° (middle range) and 110 ° (end range) to evaluate knee proprioception when the PCL is under different amounts of tension. TTDPM and RPP were tested as the knee moved into flexion and extension from both starting positions. A statistically significant reduction in TTDPM was identified in PCL-injured knees tested from the 45 ° starting position, moving into flexion and extension. RPP was statistically better in the PCL-deficient knee as tested from 110 ° moving into flexion and extension. No difference was identified in the TTDPM starting at 110 ° or in RPP with the presented angle at 45 ° moving into flexion or extension. These subtle but statistically significant findings suggest that proprioceptive mechanoreceptors may play a clinical role in PCL-intact and PCL-deficient patients. Further, it appears that kinesthesia and joint position sense may function through different mechanisms.


Journal of Shoulder and Elbow Surgery | 2012

The docking technique for lateral ulnar collateral ligament reconstruction: surgical technique and clinical outcomes

Kristofer J. Jones; Christopher C. Dodson; Daryl C. Osbahr; Robert L. Parisien; Andrew J. Weiland; David W. Altchek; Answorth A. Allen

HYPOTHESIS Lateral ulnar collateral ligament (LUCL) reconstruction is a commonly used surgical approach for the treatment of posterolateral rotatory instability (PLRI). We hypothesized that favorable clinical results could be obtained using the docking technique. MATERIALS AND METHODS Between 1996 and 2009, the docking technique was used for surgical reconstruction of the LUCL in 8 patients with purely ligamentous posterolateral rotatory instability of the elbow. The clinical results of these patients were retrospectively reviewed. RESULTS At a mean follow-up of 7.1 years (range, 5.2-9.4 years), 6 patients (75%) demonstrated complete resolution of lateral elbow instability, and 2 (25%) reported occasional instability with activities of daily living. The mean Mayo Elbow Performance Score was 87.5 (range, 75-100). Subjective assessment revealed that all patients were satisfied with their clinical outcome. CONCLUSION LUCL reconstruction using the docking technique facilitates simple graft tensioning and excellent graft fixation. Clinical results are comparable with previously reported studies with a low complication rate.


Sports Health: A Multidisciplinary Approach | 2010

Injury in the National Basketball Association: A 17-Year Overview

Mark C. Drakos; Benjamin G. Domb; Chad Starkey; Lisa R. Callahan; Answorth A. Allen

Background: Injury patterns in elite athletes over long periods continue to evolve. The goal of this study was to review of the injuries and medical conditions afflicting athletes competing in the National Basketball Association (NBA) over a 17-year period. Design: Descriptive epidemiological study. Methods: Injuries and player demographic information were reported by each team’s athletic trainer. Criteria for reportable injuries were those that resulted in (1) physician referral, (2) a practice or game being missed, or (3) emergency care. The demographics, frequency of injury, time lost, and game exposures were tabulated, and game-related injury rates and 95% confidence intervals were calculated. Results: A total of 1094 players appeared in the database 3843 times (3.3 ± 2.6 seasons). Lateral ankle sprains were the most frequent orthopaedic injury (n, 1658; 13.2%), followed by patellofemoral inflammation (n, 1493; 11.9%), lumbar strains (n, 999; 7.9%), and hamstring strains (n, 413; 3.3%). The most games missed were related to patellofemoral inflammation (n, 10 370; 17.5%), lateral ankle sprains (n, 5223; 8.8%), knee sprains (n, 4369; 7.4%), and lumbar strains (n, 3933; 6.6%). No correlations were found between injury rate and player demographics, including age, height, weight, and NBA experience. Conclusion: Professional athletes in the NBA experience a high rate of game-related injuries. Patellofemoral inflammation is the most significant problem in terms of days lost in competition, whereas ankle sprains are the most common injury. True ligamentous injuries of the knee were surprisingly rare. Importantly, player demographics were not correlated with injury rates. Further investigation is necessary regarding the consequences and sport-specific treatment of various injuries in NBA players. Clinical Relevance: Knowledge of these injury patterns can help to guide treatments and provide more accurate guidelines for an athlete to return to play.

Collaboration


Dive into the Answorth A. Allen's collaboration.

Top Co-Authors

Avatar

David W. Altchek

Hospital for Special Surgery

View shared research outputs
Top Co-Authors

Avatar

Russell F. Warren

Hospital for Special Surgery

View shared research outputs
Top Co-Authors

Avatar

Mark C. Drakos

Hospital for Special Surgery

View shared research outputs
Top Co-Authors

Avatar

Richard Ma

University of Missouri

View shared research outputs
Top Co-Authors

Avatar

Victor Lopez

United States Department of Health and Human Services

View shared research outputs
Top Co-Authors

Avatar

Riley J. Williams

Hospital for Special Surgery

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Frank A. Cordasco

Hospital for Special Surgery

View shared research outputs
Researchain Logo
Decentralizing Knowledge