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Biomedical subjects

Augustus D Mazzocca

Publications and source records attributed to Augustus D Mazzocca.

At least 19 recordsLinked to original sources
PubMed2006

Biomechanical evaluation of 4 techniques of distal biceps brachii tendon repair.

BACKGROUND: Recent technical improvements have led the way to a resurgence of the single-incision approach for repair of distal biceps tendon injuries. There has been no biomechanical evaluation of all these techniques with comparison to the standard 2-incision bone tunnel technique. HYPOTHESIS: There will be no difference under cyclic loading and ultimate failure between the 2-incision bone tunnel technique, suture anchor repair, interference screw, and EndoButton techniques for the repair of distal biceps tendon ruptures. STUDY DESIGN: Controlled laboratory study. METHODS: Sixty-three fresh-frozen cadaveric elbows were randomly assigned to 4 treatment groups (bone tunnel, EndoButton, suture anchor, interference screw). Cyclic loading was then performed from 0 degrees to 90 degrees at 0.5 Hz for 3600 cycles with a 50-N load. A differential variable reductance transducer was placed between the radius and distal tendon to determine displacement. The construct was then pulled to failure at 120 mm/min. RESULTS: A multiple analysis of variance revealed no statistically significant difference for displacement among the 4 repair techniques. Displacement using the bone tunnel was 3.55 mm, EndoButton was 3.42 mm, suture anchor was 2.33 mm, and interference screw was 2.15 mm. There was a statistically significant greater load to failure with EndoButton (440 N) than suture anchor (381 N), bone tunnel (310 N), or interference screw (232 N) (P < .001). CONCLUSION: The EndoButton technique had the highest load to failure. CLINICAL RELEVANCE: These data demonstrate the EndoButton to be the strongest repair technique, with no failures during cycling at physiologic loads and with the largest load to failure. These findings are important in maximizing surgical results and stability and suggest that the construct can tolerate early postoperative active range of motion.

Arm↗
PubMed2006

The anatomy of the bicipital tuberosity and distal biceps tendon.

The anatomy of the distal biceps tendon and bicipital tuberosity (BT) is important in the pathophysiology of tendon rupture, as well as surgical repair. Understanding the dimensions of the BT and its angular relationship to the radial head and radial styloid will facilitate surgical procedures such as reconstruction of the distal biceps tendon, radial head prosthesis implantation, and reconstruction of proximal radius trauma. We examined 178 dried cadaveric radii, and the following measurements were collected: radial length, length and width of the BT, diameter of the radius just distal to the BT, distance from the radial head to the BT, radial head diameter, width of the radius at the BT, radial neck-shaft angle, and styloid angle. Furthermore, the morphology of the BT ridge was defined as smooth (absent), small, medium, large, or bifid. Of the specimens, 48 were further analyzed with a computed tomography scanner at the level of the BT to determine the distance to traverse both the anterior and posterior cortex and the anterior cortex alone. Eighteen fresh-frozen cadaveric elbows were dissected, and the insertion footprint of the distal biceps tendon was defined. The BT has a mean length of 22 +/- 3 mm and a mean width of 15 +/- 2 mm. The tendon insertion footprint is a ribbon-shaped configuration on the most ulnar aspect of the BT, and it occupies 63% of the length and 13% of the width of the BT. The BT ridge is absent in 6% of specimens and bifid in 6%, and the remaining 88% of specimens have a single ridge that may be classified as small, medium, or large. The mean diameter of the radial head is 22 +/- 3 mm. The mean radial neck-shaft angle is 7 degrees +/- 3 degrees , and the mean BT-radial styloid angle is 123 degrees +/- 10 degrees . None of the measurements correlated with patient age, sex, or race. We concluded that the morphology of the BT ridge is variable. The insertion footprint of the distal biceps tendon is on the ulnar aspect of the BT ridge. The dimensions of the radius and BT are applicable to several surgical procedures about the elbow.

Cadaver↗
PubMed2006

Medial opening wedge tibial osteotomy and the sagittal plane: the effect of increasing tibial slope on tibiofemoral contact pressure.

BACKGROUND: Altering the tibial slope in an anterior cruciate ligament-deficient knee has been shown to affect anterior-posterior tibial translation. The effects on articular contact pressure of altering tibial slope during a high tibial osteotomy are unknown. HYPOTHESES: Performing an opening wedge osteotomy anterior to the midaxial line will increase tibial slope. Increasing tibial slope with a high tibial osteotomy in an anterior cruciate ligament-deficient knee redistributes tibiofemoral joint contact pressures onto the posterior tibial plateau. STUDY DESIGN: Controlled laboratory study. METHODS: Medial opening wedge high tibial osteotomies were performed, and a plate fixation with a known diameter inset was placed along the medial tibia in an anterior position and a posterior position on 9 cadaveric knees. Medial and lateral tibiofemoral contact pressures were measured at the resulting 2 different tibial slopes in both ligament-intact and ligament-deficient states using thin electronic sensors. RESULTS: Anterior plate application resulted in an increase in posterior tibial slope by an average of 6.6 degrees (P < .001) compared with posterior plate placement. After medial opening wedge high tibial osteotomy, the mean peak lateral tibiofemoral contact pressure (3.4 MPa) was significantly greater (P = .002) than was the mean peak medial pressure (2.6 MPa). In ligament-intact specimens, altering the tibial slope did not significantly shift peak contact pressures. However, in ligament-deficient knees, increasing tibial slope by an average of 5.5 degrees significantly redistributed the location of peak intra-articular pressure, shifting it posteriorly by 24% (P = .003). CONCLUSION: Increasing tibial slope in anterior cruciate ligament-deficient knees with a high tibial osteotomy redistributes pressure into the posterior tibial plateau. CLINICAL RELEVANCE: In knees with chronic anterior cruciate ligament deficiency, posteromedial compartment degeneration is observed. Inadvertent redistribution of contact pressure into this area may be a cause of pain and premature clinical failure after medial opening wedge tibial osteotomy.

Aged↗
PubMed2006

Residual strength of the quadriceps versus patellar tendon after harvesting a central free tendon graft.

PURPOSE: Free tendon grafts for reconstruction of the anterior cruciate ligament have become more prevalent with the desire for reduced morbidity, earlier postoperative rehabilitation, and improved free tendon graft fixation. The central quadriceps tendon autograft is an alternative to bone-patellar tendon-bone and free hamstring autografts. The purpose of this study was to measure the postharvest reduction in quadriceps extensor mechanism strength when a central quadriceps free tendon graft is removed. The strength deficit was compared with that associated with harvesting a central free patellar tendon graft, excluding the effects of harvesting bone blocks. TYPE OF STUDY: Experimental laboratory study. METHODS: Fourteen knee extensor mechanisms were divided into quadriceps and patellar tendon constructs. Constructs were tested to failure in tension in either the intact state or after removing 10-mm wide central free tendon grafts. Failure strengths of the quadriceps and patellar tendon constructs were compared statistically using paired and unpaired t tests. RESULTS: The average strength (+/-SD) measured for the native quadriceps tendon was 3,660 +/- 830 N, decreasing to 2,430 +/- 680 N after removing a partial-thickness 10-mm wide central free graft. The average strength measured for the native patellar tendon was 1,920 +/- 330 N, decreasing to 1,460 +/- 740 N after removing a 10-mm wide central free graft. CONCLUSIONS: The tensile strength of the quadriceps tendon is reduced by approximately one third after harvesting a partial-thickness 10-mm wide central free tendon graft. This postharvest strength of the quadriceps tendon is higher than that of the intact patellar tendon. CLINICAL RELEVANCE: Surgeons can be assured that harvest of a central quadriceps free tendon graft leaves a stronger extensor mechanism than harvest of a patellar tendon graft.

Animals↗
PubMed2006

Ulnar nerve palsy after elbow arthroscopy.

Reports of ulnar nerve injury as a result of elbow arthroscopy are rare in the literature. We report a case of ulnar nerve injury following arthroscopic debridement and retrograde drilling of the capitulum in a patient with symptomatic osteochondritis dissecans. The standard location of proximal medial portal placement is 2 cm proximal to the medial epicondyle at the level of the medial intermuscular septum. In this location, the ulnar nerve is protected from injury by the medial intermuscular septum. Extending this placement more proximally may negate this protection, leaving the nerve more susceptible to injury.

Adolescent↗
PubMed2006

A prospective outcome evaluation of arthroscopic Bankart repairs: minimum 2-year follow-up.

BACKGROUND: Arthroscopic treatment of anterior shoulder dislocation has become possible through improvements in instruments and techniques. OBJECTIVE: To prospectively evaluate results of arthroscopic Bankart repairs at a minimum 2-year follow-up for patients with histories of shoulder dislocation and an anterior-inferior labral tear at the time of diagnostic arthroscopy. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A consecutive series of 85 patients (70 men, 15 women; mean age, 26 years) with Bankart lesions were treated with arthroscopic repair using suture anchors; 18 patients (27%) had extension of the labral injury into the superior labrum affecting some or all of the biceps anchor. Anchors were loaded with no. 2 nonabsorbable braided suture and placed 2 mm into the edge of the glenoid surface. A low anterior (5-o'clock) portal through the subscapularis tendon was used in all patients; 72 patients were evaluated at a minimum of 2 years postoperatively (mean, 46 months). RESULTS: Seven patients (10%) experienced recurrent instability after repair. Four patients had redislocations; 3 experienced recurrent subluxations. One patient had pain with the apprehension test without a clear history of recurrent instability. Of 18 collision athletes, 2 had dislocations at 22 and 60 months postoperatively. There were no complications, including no neurologic deficits. Clinical strength testing of the subscapularis muscle was normal in all patients. The mean Rowe score was 88 of 100 points, with 90% excellent or good results. Simple Shoulder Test responses improved from 66% positive preoperatively to 88% positive postoperatively. The American Shoulder and Elbow Surgeons scoring index averaged 92 of 100 points postoperatively. Pain analog scales improved from 5.5 preoperatively to 0.35 postoperatively on a 10-point scale. SF-12 scores improved for physical function. Patient satisfaction was rated 8.9 on a 10-point visual analog scale. CONCLUSION: Bankart repairs performed arthroscopically using properly implanted suture anchors and nonabsorbable sutures and in which associated pathoanatomy is addressed demonstrate low recurrence rates (10%) similar to historical open controls.

Adult↗
PubMed2005

A biomechanical evaluation of an anatomical coracoclavicular ligament reconstruction.

BACKGROUND: Despite numerous surgical techniques described, there have been few studies evaluating the biomechanical performance of acromioclavicular joint reconstructions. PURPOSE: To compare a newly developed anatomical coracoclavicular ligament reconstruction with a modified Weaver-Dunn procedure and a recently described arthroscopic method using ultrastrong nonabsorbable suture material. STUDY DESIGN: Controlled laboratory study. METHODS: Forty-two fresh-frozen cadaveric shoulders (72.8 +/- 13.4 years) were randomly assigned to 3 groups: arthroscopic reconstruction, anatomical coracoclavicular reconstruction, and a modified Weaver-Dunn procedure. Bone mineral density was obtained on all specimens. Specimens were tested to 70 N in 3 directions, anterior, posterior, and superior, comparing the intact to the reconstructed states. Superior cyclic loading at 70 N for 3000 cycles was then performed at a rate of 1 Hz, followed by a load to failure test (120 mm/min) to simulate physiologic states at the acromioclavicular joint. RESULTS: In comparison to the intact state, the modified Weaver-Dunn procedure had significantly (P < .05) greater laxity than the anatomical coracoclavicular reconstruction or the arthroscopic reconstruction. There were no significant differences in bone mineral density (g/cm(2)), load to failure, superior migration over 3000 cycles, or superior displacement. The anatomical coracoclavicular reconstruction had significantly less (P < .05) anterior and posterior translation than the modified Weaver-Dunn procedure. The arthroscopic reconstruction yielded significantly less anterior displacement (P < .05) than the modified Weaver-Dunn procedure. CONCLUSION: The anatomical coracoclavicular reconstruction has less anterior and posterior translation and more closely approximates the intact state, restoring function of the acromioclavicular and coracoclavicular ligaments. CLINICAL RELEVANCE: A more anatomical reconstruction using a free tendon graft of both the trapezoid and conoid ligaments may provide a stronger, permanent biologic solution for dislocation of the acromioclavicular joint. This reconstruction may minimize recurrent subluxation and residual pain and permit earlier rehabilitation.

Acromioclavicular Joint↗
PubMed2005

Arthroscopic single-row versus double-row suture anchor rotator cuff repair.

BACKGROUND: Recurrent defects after open and arthroscopic rotator cuff repair are common. Double-row repair techniques may improve initial fixation and quality of rotator cuff repair. PURPOSE: To evaluate the load to failure, cyclic displacement, and anatomical footprint of 4 arthroscopic rotator cuff repair techniques. HYPOTHESIS: Double-row suture anchor repair would have superior structural properties and would create a larger footprint compared to single-row repair. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty fresh-frozen cadaveric shoulders were randomly assigned to 4 arthroscopic repair techniques. The repair was performed as either a single-row technique or 1 of 3 double-row techniques: diamond, mattress double anchor, or modified mattress double anchor. Angle of loading, anchor type, bone mineral density, anchor distribution, angle of anchor insertion, arthroscopic technique, and suture type and size were all controlled. Footprint length and width were quantified before and after repair. Displacement with cyclic loading and load to failure were determined. RESULTS: There were no differences in load to failure and displacement with cyclic loading between the single-row repair and each double-row repair. All repair groups demonstrated load to failure greater than 250 N. A significantly greater supraspinatus footprint width was seen with double-row techniques compared to single-row repair. CONCLUSIONS: The single-row repair technique was similar to the double-row techniques in load to failure, cyclic displacement, and gap formation. The double-row anchor repairs consistently restored a larger footprint than did the single-row method. CLINICAL RELEVANCE: The arthroscopic techniques studied have strong structural properties that approached the reported performance of open repair techniques. Double-row techniques provide a larger footprint width; although not addressed by this study, such a factor may improve the biological quality of repair.

Absorbable Implants↗
PubMed2005

Subpectoral biceps tenodesis with interference screw fixation.

The proximal portion of the long head of the biceps is a recognized cause of anterior shoulder pain. This article presents a novel technique for tenodesing the proximal biceps tendon. The tendon is evaluated and tenodesed in the same anatomic position beneath the pectoralis tendon, and is removed entirely from the bicipital groove. The proximal portion of the long head of the biceps tendon is marked near its origin and lysed arthroscopically. The skin incision for the subpectoral open biceps tenodesis is made in the axilla exposing the inferior border of the pectoralis major muscle. The tendon is withdrawn from the joint and out of the incision. A Krackow or other type of interrupted tendon whipstitch is placed in the 10 to 15 mm of tendon proximal to the musculotendinous junction. A bone tunnel is created within the bicipital groove. The tendon/tenodesis driver complex is positioned to create a secure fit within the bone tunnel. Our current series includes 22 cases with short-term follow-up of 2 to 10 months. None of the repairs has pulled out and none of the patients reports persistent pain or loss of function. The subpectoral approach with interference screw fixation appears to be a promising, reproducible technique for tenodesing the biceps.

Bone Screws↗
PubMed2005

Mini-open repair technique of HAGL (humeral avulsion of the glenohumeral ligament) lesion.

This article describes a limited open technique to repair humeral avulsions of the glenohumeral ligament (HAGL). The main feature of this technique is the sparing of the superior 50% of the subscapularis tendon. Essentially, an L-type incision is made in the lower third of the subscapularis tendon approximately 1 cm medial to the lesser tuberosity. The transverse limb of this incision is made just superior to the anterior circumflex vessels. Beginning inferiorly, the subscapularis tendon is lifted up, exposing the humeral ligament avulsion. The HAGL lesion is then repaired with 2 or 3 suture anchors anatomically. The advantages of this technique are preservation of the important superior tendinous portion of the subscapularis tendon, thereby preserving strength, easier rehabilitation, and return to full activity.

Exercise Therapy↗
PubMed2005

The biomechanical evaluation of four fixation techniques for proximal biceps tenodesis.

PURPOSE: The purpose of this study was to compare the cyclic displacement and ultimate failure strength of 4 proximal biceps tendon tenodesis fixation methods: the open subpectoral bone tunnel (SBT) biceps tenodesis, the arthroscopic suture anchor (SA) tenodesis, the open subpectoral interference screw (SIS) fixation technique, and the arthroscopic interference screw (AIS) technique. TYPE OF STUDY: Biomechanical experimental control. METHODS: Twenty fresh-frozen cadaver shoulders were dissected free of soft tissues, leaving the proximal humerus and the proximal biceps tendon as a free graft. Specimens were randomized to 1 of 4 groups with 5 total specimens in each group. A proximal biceps tenodesis was performed according to the techniques listed above. The specimens were mounted for an axial pull of the biceps tendon on a servohydraulic materials testing system with a 100-N load cycled at 1 Hz for 5,000 cycles, followed by an axial load to failure test. Cyclic displacement, ultimate load to failure, and site of failure were recorded for each specimen. RESULTS: The mean cyclic displacement recorded for each experimental group was as follows: SBT group, 9.39 +/- 2.82 mm; AIS group, 5.26 +/- 2.60 mm; SIS group, 1.53 +/- 0.60 mm; and SA group, 3.87 +/- 2.11 mm. The mean ultimate failure loads after 5,000 cycles were as follows: SBT group, 242.4 +/- 51.33 N; AIS group, 237.6 +/- 27.58 N; SIS group, 252.4 +/- 68.63 N; and SA group, 164.8 +/- 37.47 N. Each specimen failed at the tenodesis site. CONCLUSIONS: The SBT group showed statistically significant greater displacement than the other tenodesis methods. There were no statistically significant differences in ultimate failure strength between any of the biceps tenodesis methods tested. CLINICAL RELEVANCE: The data serve as a guide to the surgeon performing a proximal biceps tenodesis in choosing a fixation method.

Aged↗
PubMed2005

Arthroscopic anterior shoulder stabilization of collision and contact athletes.

BACKGROUND: Repair of the anterior labrum (Bankart lesion) with tightening of the ligaments (capsulorrhaphy) is the recommended treatment for recurrent anterior glenohumeral dislocations. Current evidence suggests that arthroscopic anterior stabilization methods yield similar failure rates for resubluxation and redislocation when compared to open techniques. STUDY DESIGN: Case series; Level of evidence, 4 PURPOSE: To examine the results of arthroscopic anterior shoulder stabilization of high-demand collision and contact athletes. METHODS: Thirteen collision and 5 contact athletes were identified from the senior surgeon's case registry. Analysis was limited to patients younger than 20 years who were involved in collision (football) or contact (wrestling, soccer) athletics. Objective testing included preoperative and postoperative range of motion and stability. Outcome measures included the American Shoulder and Elbow Society shoulder score, Simple Shoulder Test, SF-36, and Rowe scores. The surgical procedure was performed in a consistent manner: suture anchor repair of the displaced labrum, capsulorrhaphy with suture placement supplemented with thermal treatment of the capsule when indicated, and occasional rotator interval closure. Average follow-up was 37 months (range, 24-66 months). RESULTS: Two of 18 contact and collision athletes (11%) experienced recurrent dislocations after the procedure; both were collision athletes. One returned to play 3 years of high school football but failed after diving into a pool. One patient failed in his second season after his stabilization (>2 years) when making a tackle. None of the contact athletes experienced a recurrent dislocation, with all of them returning to high school or college athletics. CONCLUSIONS: One hundred percent of all collision and contact athletes returned to organized high school or college sports. Fifteen percent of those collision athletes had a recurrence, which has not required treatment. Participation in collision and contact athletics is not a contraindication for arthroscopic anterior shoulder stabilization using suture anchors, proper suture placement, capsulorrhaphy, and occasional rotator interval plication.

Adolescent↗
PubMed2004

Arthroscopic biceps tenodesis.

Arthroscopic biceps tenodesis is indicated for the treatment of severe biceps tendonopathy, partial- or full-thickness tendon tears, or biceps instability typically associated with rotator cuff tear, although there has been considerable debate on tenotomy versus tenodesis. We advocate tenodesis, for the following reasons: to re-establish the resting muscle length so as to avoid scaring and spasm, to allow biceps use for complex elbow motion, and to avoid cosmetic defects in cases in which deformity can sometimes equal disability. This technical note provides illustrations and detailed descriptions of our arthroscopic tenodesis technique using a Arthrex (Naples, FL) biotenodesis system.

Absorbable Implants↗
PubMed2004

An accessory portal for posterior cruciate ligament tibial insertion visualization.

Posterior cruciate ligament (PCL) reconstruction is infrequently performed, technically challenging, and has less predictable results compared with its anterior cruciate ligament (ACL) counterpart. Creation of a transtibial tunnel has been associated with catastrophic neurovascular complications, as well as tunnel malpositioning. This technical note reports the use of the femoral PCL tunnel to visually access the posterior slope for tibial tunnel creation. This technique modification allows concurrent placement of instruments through an inferomedial and/or posteromedial portal to facilitate PCL insertional debridement, placement of the tibial aimer, and creation of the tunnel. We feel that this technical modification provides superior visualization of this anatomic area.

Arthroscopes↗
PubMed2004

Evaluation and management of acromioclavicular joint injuries.

The acromioclavicular joint is stabilized by the coracoclavicular and acromioclavicular ligaments and by the trapezius and deltoid muscles. Joint dislocation commonly results from a direct blow to the acromion. Injury types I through III are generally treated nonoperatively, whereas types IV through VI are treated operatively. Nonoperative protocols should always begin with ice and immobilization. Operative techniques include acromioclavicular ligament repair, dynamic transfer of the conjoined tendon, coracoclavicular ligament reconstruction, and coracoacromial ligament transfer. The goal with any injury type should always be full return to the patient's preinjury condition.

Acromioclavicular Joint↗
PubMed2003

Valgus medial collateral ligament rupture causes concomitant loading and damage of the anterior cruciate ligament.

This study tested the hypothesis that application of a valgus force necessary to create a complete medial collateral ligament (MCL) injury causes damage to the anterior cruciate ligament (ACL). Twelve cadaveric knees were used to measure concomitant loading and damage to the ACL in valgus knee loading sufficient to cause a grade III MCL injury. Displacement sensors were placed on the anteromedial bundle of the ACL and posterior oblique ligament to monitor tensile strain during creation of the MCL injury. A valgus moment was applied to knees flexed at 30 degrees, displacing the joint into valgus rotation beyond MCL rupture. Following valgus loading and MCL injury, femur-ACL-tibia specimens were tested to failure to compare ACL mechanical integrity to noninjured control specimens. Average ACL strength in MCL ruptured knees (1250 +/- 90 N) was statistically lower (P < or = .05) than that for control knees (2110 +/- 50 N). Strain measurements exhibited concomitant posterior oblique ligament strain during valgus loading, whereas ACL strain increased substantially only after MCL rupture. These data indicate that the ACL can be compromised in isolated grade III MCL injuries.

Anterior Cruciate Ligament↗