Augustus D. Mazzocca

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/cm2), 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.

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.

Evaluation and Treatment of Acromioclavicular Joint Injuries

Acromioclavicular joint injuries and, more specifically, separations are commonplace both in general practice and during athletic participation. This article reviews the traditional classification as well as the clinical evaluation of patients with acute and chronic acromioclavicular joint separations. It also highlights many recent advances, principally in the anatomy and biomechanics of the acromioclavicular joint ligamentous complex. The concept of increases in superior translation as well as disturbances in horizontal translation with injuries to this joint and ligaments are discussed. This information, coupled with the unpredictable longterm results with the Weaver-Dunn procedure and its modifications, have prompted many recent biomechanical studies evaluating potential improvements in the surgical management of acute and chronic injuries. The authors present these recent works investigating cyclic loading and ultimate failure of traditional reconstructions, augmentations, use of free graft, and the more recent anatomic reconstruction of the conoid and trapezoid ligaments. The clinical results (largely retrospective), including acromioclavicular joint repair, reconstruction and augmentation with the coracoclavicular ligament, supplemental sutures, and the use of free autogenous grafts, are summarized. Finally, complications and the concept of the failed distal clavicle resection and reconstruction are addressed. The intent is to provide a current, in-depth treatise on all aspects of acromioclavicular joint complex injuries to include anatomy, biomechanics, benchmark studies on instability and reconstruction, clinical and radiographic evaluation, and to present the most recent clinical research on surgical outcomes.

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 surgeons 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.

Anatomy of the Clavicle and Coracoid Process for Reconstruction of the Coracoclavicular Ligaments

Background Recently acromioclavicular joint reconstruction techniques have focused on anatomic restoration of the coracoclavicular (CC) ligaments. Such techniques involve creating bone tunnels in the distal clavicle and coracoid. Purpose To define the anatomy of the human clavicle and coracoid process of the scapula, in order to guide surgeons in reconstructing the CC ligaments. Study Design Descriptive laboratory study. Methods One hundred twenty (60 paired) cadaveric clavicles and corresponding scapulae (mean age ± and standard deviation, 48.3 ± 16.6 years) devoid of soft tissue were analyzed (dry osteology). Differences related to race and sex were recorded. Nineteen fresh-frozen cadaveric clavicles with intact CC ligaments were measured as well (fresh anatomic). Results The mean clavicle length was 149 ± 9.1 mm. In the dry osteology group, the distance from the lateral edge of the clavicle to the medial edge of the conoid tuberosity in male and female specimens was 47.2 ± 4.6 mm and 42.8 ± 5.6 mm, respectively (P = .006). The distance to the center of the trapezoid tuberosity was 25.4 ± 3.7 mm in males and 22.9 ± 3.7 mm in females (P = .04). The ratio of the distance to the medial edge of the conoid tuberosity divided by clavicle length was 0.31 in males and females. This ratio for the trapezoid was 0.17 in both sexes. The mean coracoid length was 45.2 ± 4.1 mm. The mean width and height of the coracoid process were 24.9 ± 2.5 mm and 11.9 ± 1.8 mm, respectively. No interracial differences in measurements were observed. In the fresh anatomic samples, the ratio of the distance to the conoid center to clavicle length was 0.24. This ratio for the trapezoid was 0.17. Conclusions While absolute differences in the origin of the CC ligaments exist between men and women, the ratio of these origins to total clavicle length is constant. Clinical Relevance Clavicle length can be obtained intraoperatively. These findings allow the surgeon to predict the origin of the conoid and trapezoid ligaments accurately and to correctly create bone tunnels to reconstruct the anatomy of the CC complex.

Platelet-Rich Plasma Differs According to Preparation Method and Human Variability

BACKGROUND Varying concentrations of blood components in platelet-rich plasma preparations may contribute to the variable results seen in recently published clinical studies. The purposes of this investigation were (1) to quantify the level of platelets, growth factors, red blood cells, and white blood cells in so-called one-step (clinically used commercial devices) and two-step separation systems and (2) to determine the influence of three separate blood draws on the resulting components of platelet-rich plasma. METHODS Three different platelet-rich plasma (PRP) separation methods (on blood samples from eight subjects with a mean age [and standard deviation] of 31.6 ± 10.9 years) were used: two single-spin processes (PRPLP and PRPHP) and a double-spin process (PRPDS) were evaluated for concentrations of platelets, red and white blood cells, and growth factors. Additionally, the effect of three repetitive blood draws on platelet-rich plasma components was evaluated. RESULTS The content and concentrations of platelets, white blood cells, and growth factors for each method of separation differed significantly. All separation techniques resulted in a significant increase in platelet concentration compared with native blood. Platelet and white blood-cell concentrations of the PRPHP procedure were significantly higher than platelet and white blood-cell concentrations produced by the so-called single-step PRPLP and the so-called two-step PRPDS procedures, although significant differences between PRPLP and PRPDS were not observed. Comparing the results of the three blood draws with regard to the reliability of platelet number and cell counts, wide variations of intra-individual numbers were observed. CONCLUSIONS Single-step procedures are capable of producing sufficient amounts of platelets for clinical usage. Within the evaluated procedures, platelet numbers and numbers of white blood cells differ significantly. The intra-individual results of platelet-rich plasma separations showed wide variations in platelet and cell numbers as well as levels of growth factors regardless of separation method.

Platelet-Rich Plasma: The PAW Classification System

Platelet-rich plasma (PRP) has been the subject of hundreds of publications in recent years. Reports of its effects in tissue, both positive and negative, have generated great interest in the orthopaedic community. Protocols for PRP preparation vary widely between authors and are often not well documented in the literature, making results difficult to compare or replicate. A classification system is needed to more accurately compare protocols and results and effectively group studies together for meta-analysis. Although some classification systems have been proposed, no single system takes into account the multitude of variables that determine the efficacy of PRP. In this article we propose a simple method for organizing and comparing results in the literature. The PAW classification system is based on 3 components: (1) the absolute number of Platelets, (2) the manner in which platelet Activation occurs, and (3) the presence or absence of White cells. By analyzing these 3 variables, we are able to accurately compare publications.

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° to 90° 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.

Current Concepts in the Treatment of Acromioclavicular Joint Dislocations

PURPOSE To conduct a systematic review of the literature in relation to 3 considerations in determining treatment options for patients with acromioclavicular (AC) joint dislocations: (1) operative versus nonoperative management, (2) early versus delayed surgical intervention, and (3) anatomic versus nonanatomic techniques. METHODS The PubMed database was searched in October 2011 using the single term acromioclavicular and the following search limits: any date, humans, English, and all adult (19+). Studies were included if they compared operative with nonoperative treatment, early with delayed surgical intervention, or anatomic with nonanatomic surgical techniques. Exclusion criteria consisted of the following: Level V evidence, laboratory studies, radiographic studies, biomechanical studies, fractures or revisions, meta-analyses, and studies reporting preliminary results. RESULTS This query resulted in 821 citations. Of these, 617 were excluded based on the title of the study. The abstracts and articles were reviewed, which resulted in the final group of 20 studies that consisted of 14 comparing operative with nonoperative treatment, 4 comparing early with delayed surgical intervention, and 2 comparing anatomic with nonanatomic surgical techniques. The lack of higher level evidence prompted review of previously excluded studies in an effort to explore patterns of publication related to operative treatment of the AC joint. This review identified 120 studies describing 162 techniques for operative reconstruction of the AC joint. CONCLUSIONS There is a lack of evidence to support treatment options for patients with AC joint dislocations. Although there is a general consensus for nonoperative treatment of Rockwood type I and II lesions, initial nonsurgical treatment of type III lesions, and operative intervention for Rockwood type IV to VI lesions, further research is needed to determine if differences exist regarding early versus delayed surgical intervention and anatomic versus nonanatomic surgical techniques in the treatment of patients with AC joint dislocations. LEVEL OF EVIDENCE Level III, systematic review of Level II and Level III studies and one case series.

Clinical Outcomes after Subpectoral Biceps Tenodesis with an Interference Screw

Background Subpectoral biceps tenodesis with an interference screw has been shown to be an effective procedure from both an anatomic and biomechanical perspective. There have been no clinical outcome data on this procedure to date. Hypothesis Subpectoral biceps tenodesis is an effective procedure in eliminating biceps tendinosis symptoms. Study Design Case series; Level of evidence, 4. Methods Patients who underwent subpectoral biceps tenodesis with a minimum follow-up of 1 year were evaluated using a battery of clinical outcome measures, biceps apex difference, and pain scores. A diagnosis of biceps tendinosis was made using a specific diagnostic protocol coupled with observation of biceps tendon fraying and increased erythema on dry arthroscopy. Results Between November 2002 and August 2005, 50 patients underwent subpectoral biceps tenodesis. Complete follow-up examinations were performed in 41 of 50 (82%). There were 16 women and 25 men (mean age, 50 years). Follow-up averaged 29 months (range, 12–49 months). The mean scores were 86, Rowe; 81, American Shoulder and Elbow Surgeons (ASES); 9, Simple Shoulder Test (SST); 87, Constant Murley; and 84, Single Assessment Numeric Evaluation (SANE). There was 1 failure as demonstrated by pull-out of the tendon from the bone tunnel resulting in a “Popeye” deformity on physical examination. The mean value for biceps apex distance was 0.15 cm, with 35 of 41 patients demonstrating no difference on physical examination. Twenty-three of 41 patients had complete preoperative and postoperative examinations. All clinical outcome measures demonstrated a statistically significant improvement at follow-up when compared with the preoperative scores. Thirty-one patients had identified lesions of the rotator cuff at time of arthroscopy. The mean ASES score in patients without rotator cuff lesion (89.2 ± 10.3) was significantly greater than the mean ASES for those with rotator cuff lesion (78.0 ± 21.0) (P = .0324). The mean SST score in patients without rotator cuff lesion (10.6 ± 1.5) was significantly greater than the mean ASES score for those with rotator cuff lesion (8.8 ± 2.7) (P = .0132). Conclusion Subpectoral biceps tenodesis with an interference screw is a viable treatment option for patients with symptomatic biceps tendinosis. Anterior shoulder pain and biceps symptoms were resolved with this technique. Patients with coexistent rotator cuff lesion had less favorable outcomes.