Augustus D Mazzocca

Publications (90)230.97 Total impact

• Article: Biomechanical Properties of Double- and Single-Row Suture Anchor Repair for Surgical Treatment of Insertional Achilles Tendinopathy.

  Knut Beitzel, Augustus D Mazzocca, Elifho Obopilwe, James W Boyle, James McWilliam, Lina Rincon, Yasmin Dhar, Robert A Arciero, Annunziato Amendola
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  ABSTRACT: BACKGROUND:Because of intratendinous ossifications, retrocalcaneal bursitis, or intratendinous necrosis commonly found in insertional tendinosis, it is often necessary to detach the tendon partially or entirely from its tendon-to-bone junction. HYPOTHESIS:Double-row repair for insertional Achilles tendinopathy will generate an increased contact area and demonstrate higher biomechanical stability. STUDY DESIGN:Controlled laboratory study. METHODS:Eighteen cadaver Achilles tendons were split longitudinally and detached, exposing the calcaneus; an ostectomy was performed and the tendon was reattached to the calcaneus in 1 of 2 ways: 2 suture anchors (single row) or a 4-anchor (double row) construct. Footprint area measurements over time, displacement after cyclic loading (2000 cycles), and final load to failure were measured. RESULTS:The double-row refixation technique was statistically superior to the single-row technique in footprint area measurement initially and 5 minutes after repair (P = .009 and P = .01, respectively) but not after 24 hours (P = .713). The double-row construct demonstrated significantly improved measures for peak load (433.9 ± 84.3 N vs 212.0 ± 49.7 N; P = .042), load at yield (354.7 ± 106.2 N vs 198.7 ± 39.5 N; P = .01), and slope (51.8 ± 9.9 N/mm vs 66.7 ± 16.2 N/mm; P = .021). Cyclic loading did not demonstrate significant differences between the 2 constructs. CONCLUSION:Double-row construct for reinsertion of a completely detached Achilles tendon using proximal and distal rows resulted in significantly larger contact area initially and 5 minutes after repair and led to significantly higher peak load to failure on destructive testing. CLINICAL RELEVANCE:In treatment for insertional Achilles tendinosis, the tendon often has to be detached and anatomically reattached to its insertion at the calcaneus. To our knowledge there is a lack of biomechanical studies supporting either a number or a pattern of suture anchor fixation. Because the stresses going across the insertion site of the Achilles tendon are significant during rehabilitation and weightbearing activities, it is imperative to have a strong construct that allows satisfactory healing during the early postoperative process.
  The American journal of sports medicine 05/2013; · 3.61 Impact Factor
• Article: Histomorphologic Changes of the Long Head of the Biceps Tendon in Common Shoulder Pathologies.

  Augustus D Mazzocca, Mary Beth R McCarthy, Felicia A Ledgard, David M Chowaniec, William J McKinnon, Steven Delaronde, Louis J Rubino, John Apolostakos, Anthony A Romeo, Robert A Arciero, Knut Beitzel
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  ABSTRACT: PURPOSE: To assess molecular and histologic differences between the proximal (intra-articular) and distal (extra-articular) portions of the long head of the biceps (LHB) tendon in 3 different disease states (biceps instability, tendinosis, and degenerative joint disease [DJD]) compared with a healthy tendon (fresh frozen). METHODS: We used 32 LHB tendons of patients undergoing tenodesis (mean age, 54.7 ± 10.1 years) and 9 harvested tissue donors. Tendons were divided according to 4 diagnostic groups: (1) biceps instability, (2) tendinosis, (3) DJD, and (4) normal control. After sectioning, tendons were fixed in formalin and stained with H&E and alcian blue for histologic analysis. Measurements of collagen organization by use of polarized light microscopy was then performed, and protein expression for type I and type III collagen, tenascin C, and decorin was determined. RESULTS: There were no statistical differences found for protein expression of type I or type III collagen, tenascin C, or decorin. The proximal and distal regions of the tendons had statistically significant differences in alcian blue staining, with the proximal portion containing a higher amount of proteoglycan (instability, P = .001; tendinosis, P = .005; DJD, P = .008; control, P = .011). When compared with the nonpathologic control tendons, a significant increase in alcian blue staining for the proximal region was seen in all 3 groups. Total polarized light analysis showed that the distal tendon had a significantly higher intensity (organization) compared with the proximal tendon (P < .001); this was also seen in all of the diagnostic groups (instability, P = .010; tendinosis, P = .013; DJD, P = .07; control, P = .028). CONCLUSIONS: This study showed a greater degree of degeneration of the proximal (intra-articular) regions of the LHB tendon when compared with the distal regions in all pathologic groups. However, no major differences at the cellular level were found among groups. CLINICAL RELEVANCE: The pathomechanisms of the various forms of known LHB diagnoses are not yet fully understood and basic science studies may help in understanding their etiology and therefore optimizing treatment options.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 04/2013; · 3.02 Impact Factor
• Article: An In Vitro Evaluation of the Anti-Inflammatory Effects of Platelet-Rich Plasma, Ketorolac, and Methylprednisolone.

  Augustus D Mazzocca, Mary Beth R McCarthy, Jessica Intravia, Knut Beitzel, John Apostolakos, Mark P Cote, James Bradley, Robert A Arciero
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  ABSTRACT: PURPOSE: The purpose of this study was to quantify the extent of the anti-inflammatory effect of platelet-rich plasma (PRP) in a controlled in vitro environment. METHODS: Through the stimulation of human umbilical vein endothelial cells with inflammatory cytokines (tumor necrosis factor α and interferon γ), cell adhesion molecule expression (E-selectin, vascular cell adhesion molecule, and human leukocyte antigen DR) and PRP's anti-inflammatory effect can be measured. PRP was produced from 3 individuals using a single-spin (PRP(LP)) process. Treatment groups include negative (unstimulated) controls, positive (stimulated) controls, ketorolac tromethamine, methylprednisolone, PRP, ketorolac-PRP, and methylprednisolone-PRP. A fluorescence assay of the cellular inflammation markers was measured by the BioTek Synergy HT plate reader (BioTek Instruments, Winooski, VT) at 0, 1, 2, and 5 days. RESULTS: At days 2 and 5, methylprednisolone treatment showed a 2.1- to 5.8-fold reduction (P < .05) in inflammation markers over PRP. In addition, PRP and ketorolac showed a 1.4- to 2.5-fold reduction (P < .05) in cellular inflammation markers over the control. There was no statistically significant difference between ketorolac and PRP. CONCLUSIONS: Although PRP and ketorolac reduced cellular inflammation markers (E-selectin, vascular cell adhesion molecule, and human leukocyte antigen DR) compared with control, neither caused as great a reduction as methylprednisolone. CLINICAL RELEVANCE: Although PRP and ketorolac did not produce as significant a reduction in cellular inflammation markers as methylprednisolone, they reduced cellular inflammation compared with the control. These agents may have clinical application as injectable anti-inflammatory medications.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 02/2013; · 3.02 Impact Factor
• Article: Current Concepts in the Treatment of Acromioclavicular Joint Dislocations.

  Knut Beitzel, Mark P Cote, John Apostolakos, Olga Solovyova, Christopher H Judson, Connor G Ziegler, Cory M Edgar, Andreas B Imhoff, Robert A Arciero, Augustus D Mazzocca
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  ABSTRACT: 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.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 02/2013; 29(2):387-397. · 3.02 Impact Factor
• Article: Graft Fixation Is Highest With Anatomic Tunnel Positioning in Acromioclavicular Reconstruction.

  Lauren E Geaney, Knut Beitzel, David M Chowaniec, Mark P Cote, John Apostolakos, Robert A Arciero, Augustus D Mazzocca
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  ABSTRACT: PURPOSE: The purposes were to determine the bone density at specific bone tunnel locations in the clavicle and to determine ultimate load to failure of a graft fixed with an interference screw at specific areas. METHODS: Bone mass densitometry was tested at 5-mm intervals from the lateral to the medial end of 11 clavicles (mean age, 70.0 ± 17.7 years). Tunnels were drilled in 10-mm increments from the lateral edge, and tenodesis screws were used to fix semitendinosus grafts in the tunnel. Grafts were cyclically loaded, followed by load to failure. RESULTS: The bone mineral density (BMD) of the cadaveric clavicles increased from lateral (0.304 ± 0.078 g/cm(2) at 10 mm) to medial (0.760 ± 0.103 g/cm(2) at 50 mm). Load to failure increased from lateral to medial, and most specimens failed by tendon pullout. The load was 125.3 ± 42.5 N at the most lateral tunnel and 349.3 ± 120.3 N at the most medial tunnel. The Pearson correlation coefficient was 0.653 between tunnel position and load to failure, 0.659 between bone density and load to failure, and 0.803 between tunnel position and bone density. These all showed strong correlation. CONCLUSIONS: BMD shows that optimal bone density is found in the anatomic insertion area of the coracoclavicular ligaments between 20 mm and 50 mm from the lateral end of the clavicle. Low BMD correlated with decreased load to failure. CLINICAL RELEVANCE: Failure at the lateral bone tunnel in coracoclavicular ligament reconstruction may be a result of poor bone quality. When one is drilling bone tunnels for this surgery, consideration should be given to both anatomic position and bone quality.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 01/2013; · 3.02 Impact Factor
• Article: Comparison of Mesenchymal Stem Cells (Osteoprogenitors) Harvested From Proximal Humerus and Distal Femur During Arthroscopic Surgery.

  Knut Beitzel, Mary Beth R McCarthy, Mark P Cote, Thomas J S Durant, David M Chowaniec, Olga Solovyova, Ryan P Russell, Robert A Arciero, Augustus D Mazzocca
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  ABSTRACT: PURPOSE: The aim of this study was to examine the relations between age, gender, and number of viable mesenchymal stem cells (MSCs) in concentrated bone marrow (BM) obtained from the proximal humerus and distal femur during arthroscopic surgery. METHODS: BM was aspirated from either the proximal humerus (n = 55) or distal femur (n = 29) during arthroscopic surgery in 84 patients (51.3 ± 11.6 years). MSCs were obtained from fractionated bone marrow after a 5-minute spin at 1,500 rpm. Volume of BM and number of nucleated cells (NCs) were calculated, and samples were cultured for 6 days, after which point colony-forming units (CFUs) were quantified and fluorescence-activated cell sorting (FACS) analysis was performed. Simple linear regression was used to explore relations between age, gender, volume of aspirated BM, and MSCs per milliliter. RESULTS: BM aspirations yielded a mean quantity of 22.6 ± 12.3 mL. After centrifugation, 30.0 ± 16.7 × 10(6) nucleated cells/mL of concentrated BM were harvested. The proximal humerus provided 38.7 ± 52.6 × 10(6), and the distal femur, 25.9 ± 14.3 × 10(6), for an overall 766.3 ± 545.3 MSCs/mL of concentrated BM (proximal humerus: 883.9 ± 577.6, distal femur: 551.3 ± 408.1). Values did not significantly differ by age, gender, or donor site. CONCLUSIONS: Arthroscopic aspiration of bone marrow from the proximal humerus and distal femur is a reproducible technique and yields reliable concentrations of MSCs. The use of an intraoperative concentration method resulted in consistent amounts of MSCs in all clinically relevant age groups without a significant drop of the number of isolated MSCs. CLINICAL RELEVANCE: Human MSCs derived from concentrated bone marrow aspirate are a promising biological addition that may have practical use in the future of soft tissue augmentation. Arthroscopic techniques for bone marrow aspiration that do not require an additional surgical site for aspiration (e.g., iliac crest) or a second operative procedure may facilitate future use of MSCs in arthroscopic surgery.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 01/2013; · 3.02 Impact Factor
• Source

  Available from: Jeffrey M. Delong

  Dataset: PAW algorithm

  Jeffrey M DeLong, Ryan P Russell, Augustus D Mazzocca
• Article: The positive effects of different platelet-rich plasma methods on human muscle, bone, and tendon cells.

  Augustus D Mazzocca, Mary Beth R McCarthy, David M Chowaniec, Evan M Dugdale, Derek Hansen, Mark P Cote, James P Bradley, Anthony A Romeo, Robert A Arciero, Knut Beitzel
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  ABSTRACT: Clinical application of platelet-rich plasma (PRP) in the realm of orthopaedic sports medicine has yielded variable results. Differences in separation methods and variability of the individual may contribute to these variable results. To compare the effects of different PRP separation methods on human bone, muscle, and tendon cells in an in vitro model. Controlled laboratory study. Blood collected from 8 participants (mean ± SD age 31.6 ± 10.9 years) was used to obtain PRP preparations. Three different PRP separation methods were used: a single-spin process yielding a lower platelet concentration (PRP(LP)), a single-spin process yielding high platelet and white blood cell concentrations (PRP(HP)), and a double-spin that produces a higher platelet concentration and lower white blood cell concentration (PRP(DS)). Human bone, muscle, and tendon cells obtained from discarded tissue samples during shoulder surgery were placed into culture and treated with the 3 PRP preparations, control media (2% fetal bovine serum [FBS] and 10% FBS), and native blood. Radioactive thymidine assays were obtained to examine cell proliferation, and testing with enzyme-linked immunosorbent assay was used to determine growth factor concentrations. Addition of PRP(LP) to osteocytes, myocytes, and tenocytes significantly increased cell proliferation (P ≤ .05) compared with the controls. Adding PRP(DS) to osteoblasts and tenocytes increased cell proliferation significantly (P ≤ .05), but no significance was shown for its addition to myocytes. The addition of PRP(HP) significantly increased cell proliferation compared with the controls only when added to tenocytes (P ≤ .05). Osteoblasts: Proliferation was significantly increased by addition of PRP(LP) compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRP(DS) led to significantly increased proliferation compared with all controls, native blood, and PRP(HP) (P ≤ .05). Proliferation was significantly less when PRP(HP) was added compared with PRP(DS) (P ≤ .05). Myocytes: Proliferation was significantly increased by addition of PRP(LP) compared with native blood (P ≤ .05). Adding PRP(HP) or PRP(DS) to myocytes showed no significant increase in proliferation compared with the controls or the other separations. Tenocytes: Proliferation was significantly increased by addition of PRP(LP) compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRP(DS) showed a significant increase compared with the controls and native blood. For tenocytes, there was a significant increase (P ≤ .05) seen when PRP(HP) was added compared with the controls and native blood but not compared with the other separations. The primary findings of this study suggest the application of different PRP separations may result in a potential beneficial effect on the clinically relevant target cells in vitro. However, it is unclear which platelet concentration or PRP preparation may be optimal for the treatment of various cell types. In addition, a "more is better" theory for the use of higher platelet concentrations cannot be supported. This study was not intended to prove efficacy but to provide a platform for future research to be built upon. The utilization of different PRP separations may result in a potentially beneficial effect on the clinically relevant target cells in vitro, but it is unclear which platelet concentration or PRP preparation may be optimal for the treatment of various cell types.
  The American journal of sports medicine 07/2012; 40(8):1742-9. · 3.61 Impact Factor
• Article: Author's Reply.

  Knut Beitzel, Mary Beth McCarthy, Mark P Cote, David Chowaniec, Lauryn M Falcone, Justine A Falcone, Evan M Dugdale, Thomas Deberardino, Robert A Arciero, Augustus D Mazzocca
  Arthroscopy The Journal of Arthroscopic and Related Surgery 07/2012; 28(7):896-7. · 3.02 Impact Factor
• Source

  Available from: Jeffrey M. Delong

  Article: Platelet-rich plasma: the PAW classification system.

  Jeffrey M DeLong, Ryan P Russell, Augustus D Mazzocca
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  ABSTRACT: 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.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 07/2012; 28(7):998-1009. · 3.02 Impact Factor
• Article: Comparison of the retro screw and standard interference screw for ACL reconstruction.

  Robert Y Wang, Robert A Arciero, Elifho Obopilwe, Augustus D Mazzocca
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  ABSTRACT: The objective of the study was to compare the load to failure between a retro screw (RS) and a standard interference screw (IS) for tibial-sided anterior cruciate ligament (ACL) fixation. We used 20 bovine tibia and extensor tendons for the study. A group of 10 specimens underwent IS fixation while the other 10 underwent RS fixation. Within each group, five specimens had graft suture in contact (interdigitating) with the screw threads. All specimens were tested on the MTS 858 Mini Bionix II (MTS Systems, Shakopee, MN). There was no statistically significant difference between the RS and IS with respect to peak load to failure. IS with suture interdigitation failed at an average of 520 N (range: 358 to 793 N), while the RS with suture interdigitation failed at 613 N (range: 438 to 1089 N). The IS without suture interdigitation failed at 654 N and the RS without suture interdigitation at 531 N. Specimens with a whipstitch in contact with the screw did not demonstrate higher pull out strength. The RS fixation strength appears to equal the IS. Graft suture contact with screw threads does not increase fixation strength. Based on this study, using a RS for tibial ACL soft tissue graft fixation is feasible and provides equal fixation strength compared with the standard IS.
  The journal of knee surgery 07/2012; 25(3):227-35.
• Article: Biomechanical performance of subpectoral biceps tenodesis: a comparison of interference screw fixation, cortical button fixation, and interference screw diameter.

  Paul M Sethi, Arun Rajaram, Knut Beitzel, Thomas R Hackett, David M Chowaniec, Augustus D Mazzocca
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  ABSTRACT: BACKGROUND: Subpectoral biceps tenodesis with interference screw fixation allows reproducible positioning of the tendon to help maintain the length-tension relationship. The aim of our study was to evaluate the role of cortical button fixation in isolation or as an augment to interference screw fixation and to determine if the diameter of the interference screw affected fixation strength. MATERIALS AND METHODS: Thirty-two cadaveric shoulders were dissected and randomized to 1 of 4 groups: (1) 7-mm interference screw and cortical button, (2) cortical button alone, (3) 7-mm interference screw, or (4) 8-mm interference screw. Testing was performed on a materials testing system with a 100-N load cycled at 1 Hz for 5000 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 ultimate failure loads were 7-mm interference screw with cortical button augmentation, 237.8 ± 120.4 N; cortical button alone, 99.4 ± 16.9 N; 7-mm interference screw, 275.5 ± 56 N; 8-mm interference screw, 277.1 ± 42.1 N. All specimens failed through tendon failure at the screw-tendon-bone interface. CONCLUSIONS: The biomechanical performance of subpectoral biceps tenodesis with interference screw fixation was not improved with cortical button augmentation. In addition, cortical button fixation alone yielded a significantly lower ultimate load to failure compared with interference screws. Finally, the biomechanical performance of smaller-diameter interference screws with matching bone tunnels was not affected by interference screw diameter.
  Journal of shoulder and elbow surgery / American Shoulder and Elbow Surgeons ... [et al.] 06/2012; · 1.93 Impact Factor
• Article: Biomechanical evaluation of effect of coracoid tunnel placement on load to failure of fixation during repair of acromioclavicular joint dislocations.

  Joel V Ferreira, David Chowaniec, Elifho Obopilwe, Michael D Nowak, Robert A Arciero, Augustus D Mazzocca
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  ABSTRACT: To evaluate the effect of entry and exit points of the coracoid tunnel on load to failure and mode of failure, to reduce the incidence of coracoid fractures and acromioclavicular joint repair failures. This study investigates 5 tunnel placements based on different entry and exit points in the coracoid process: center-center orientation represents perfect placement of the bone tunnel and served as perfect tunnel placement in our study. Four common errors in drilling were then tested and acted as the experimental groups in our study (medial-center, center-medial, lateral-center, and center-lateral). Using 35 cadaveric shoulders (mean age, 68.0 ± 13.0 years), we tested these 5 tunnel orientations using a single repair technique (cortical button) loaded to failure on an MTS 858 Servohydraulic test system (MTS Systems, Eden Prairie, MN). A control group of 7 cadaveric shoulders without the presence of a coracoid tunnel was also tested to determine the type of fracture pattern that occurred. The coracoids without tunnel drilling fractured in patterns similar to traumatic coracoid injuries. With regard to the 5 tunnel groups, it was found that the loads to failure with center-center and medial-center tunnel placement were significantly higher than those with center-medial, center-lateral, and lateral-center tunnel placement. The failure modes of the former were primarily within the repair constructs, whereas those of the latter were primarily due to bony failure. Our biomechanical results showed a higher peak load to failure with a center-center or medial-center tunnel orientation, which may lessen the risk of coracoid fracture during drilling with a 6-mm cannulated drill bit. Proper trajectory of the drill during formation of a coracoid bone tunnel can help reduce the risk of coracoid process fracture and repair failure.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 05/2012; 28(9):1230-6. · 3.02 Impact Factor
• Article: Stability of double-row rotator cuff repair is not adversely affected by scaffold interposition between tendon and bone.

  Knut Beitzel, David M Chowaniec, Mary Beth McCarthy, Mark P Cote, Ryan P Russell, Elifho Obopilwe, Andreas B Imhoff, Robert A Arciero, Augustus D Mazzocca
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  ABSTRACT: Rotator cuff reconstructions may be improved by adding growth factors, cells, or other biologic factors into the repair zone. This usually requires a biological carrier (scaffold) to be integrated into the construct and placed in the area of tendon-to-bone healing. This needs to be done without affecting the constructs mechanics. Hypothesis/ The hypothesis was that scaffold placement, as an interposition, has no adverse effects on biomechanical properties of double-row rotator cuff repair. The purpose of this study was to examine the effect of scaffold interposition on the initial strength of rotator cuff repairs. Controlled laboratory study. Twenty-five fresh-frozen shoulders (mean age: 65.5 ± 8.9 years) were randomly assigned to 5 groups. Groups were chosen to represent a broad spectrum of commonly used scaffold types: (1) double-row repair without augmentation, (2) double-row repair with interposition of a fibrin clot (Viscogel), (3) double-row repair with interposition of a collagen scaffold (Mucograft) between tendon and bone, (4) double-row repair with interposition of human dermis patch (ArthroFlex) between tendon and bone, and (5) double-row repair with human dermis patch (ArthroFlex) placed on top of the repair. Cyclic loading to measure displacement was performed to 3000 cycles at 1 Hz with an applied 10- to 100-N load. The ultimate load to failure was determined at a rate of 31 mm/min. There were no significant differences in mean displacement under cyclic loading, slope, or energy absorbed to failure between all groups (P = .128, P = .981, P = .105). Ultimate load to failure of repairs that used the collagen patch as an interposition (573.3 ± 75.6 N) and a dermis patch on top of the reconstruction (575.8 ± 22.6 N) was higher compared with the repair without a scaffold (348.9 ± 98.8 N; P = .018 and P = .025). No significant differences were found for repairs with the fibrin clot as an interposition (426.9 ± 103.6 N) and the decellularized dermis patch as an interposition (469.9 ± 148.6 N; P = .73 and P = .35). Scaffold augmentation did not adversely affect the zero time strength of the tested standard double-row rotator cuff repairs. An increased ultimate load to failure was observed for 2 of the augmentation methods (collagen patch as an interposition and decellularized dermis patch on top of the reconstruction) compared with the nonaugmented repairs. Scaffolds intended for application of growth factors or cellular components in a repair situation did not adversely jeopardize the stability of the operative construct.
  The American journal of sports medicine 02/2012; 40(5):1148-54. · 3.61 Impact Factor
• Article: Platelet-rich plasma differs according to preparation method and human variability.

  Augustus D Mazzocca, Mary Beth R McCarthy, David M Chowaniec, Mark P Cote, Anthony A Romeo, James P Bradley, Robert A Arciero, Knut Beitzel
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  ABSTRACT: 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. 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. 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. 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.
  The Journal of Bone and Joint Surgery 02/2012; 94(4):308-16. · 3.27 Impact Factor
• Article: Inter-rater agreement of the Goutallier, Patte, and Warner classification scores using preoperative magnetic resonance imaging in patients with rotator cuff tears.

  Julienne Lippe, Jeffrey T Spang, Robin R Leger, Robert A Arciero, Augustus D Mazzocca, Kevin P Shea
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  ABSTRACT: The purpose of this study was to determine the interobserver reliability of 3 commonly used classification systems in describing preoperative magnetic resonance imaging (MRI) studies of patients undergoing surgery for full-thickness rotator cuff tears. Thirty-one patients who underwent arthroscopic rotator cuff repair and had preoperative MRI studies available were selected over a 2-year period. Three board-certified shoulder surgeons independently reviewed these images. Each was instructed in the published method for determining the Patte score on the T2 coronal images, supraspinatus and infraspinatus atrophy on the T1 sagittal images as described by Warner et al., and the Goutallier score of fatty infiltration of the supraspinatus on the T1 coronal/sagittal images. Statistical analysis was then performed to determine the interobserver agreement using the κ statistic, with the level of significance set a priori at P < .01. None of the classification systems studied yielded excellent or high interobserver reliability. The strongest agreement was found with the Patte classification assessing tendon retraction in the frontal plane (κ = 0.58). The Goutallier classification, which grades fatty infiltration of the supraspinatus, showed moderate interobserver agreement (κ = 0.53) when dichotomized into none to mild (grades 0, 1, and 2) and moderate to severe (grades 3 and 4). Muscle atrophy of both the supraspinatus and infraspinatus yielded the worst interobserver reliability, with only 28% agreement. The Goutallier, Patte, and Warner MRI classification systems for describing rotator cuff tears did not have high interobserver reliability among 3 experienced orthopaedic surgeons. Fatty infiltration of the supraspinatus and tendon retraction in the frontal planes showed only moderate reliability and moderate to high reliability, respectively. These findings have potential implications in the evaluation of the literature regarding the preoperative classification of rotator cuff tears and subsequent treatment algorithms. Level III, diagnostic agreement study with nonconsecutive patients.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 02/2012; 28(2):154-9. · 3.02 Impact Factor
• Article: Optimizing pressurized contact area in rotator cuff repair: the diamondback repair.

  Stephen S Burkhart, Patrick J Denard, Elifho Obopilwe, Augustus D Mazzocca
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  ABSTRACT: The purpose of this study was to compare tendon-bone footprint contact area over time under physiologic loads for 4 different rotator cuff repair techniques: single row (SR), triangle double row (DR), chain-link double row (CL), and diamondback double row (DBK). A supraspinatus tear was created in 28 human cadavers. Tears were fixed with 1 of 4 constructs: SR, DR, CL, or DBK. Immediate post-repair measurements of pressurized contact area were taken in neutral rotation and 0° of abduction. After a static tensile load, pressurized contact area was observed over a 160-minute period after repair. Cyclic loading was then performed. The DBK repair had the highest pressurized contact area initially, as well as the highest pressurized contact area and lowest percentage decrease in pressurized contact area after 160 minutes of testing. The DBK repair had significantly larger initial pressurized contact than CL (P = .003) and SR (P = .004) but not DR (P = .06). The DBK technique was the only technique that produced a pressurized contact area that exceeded the native footprint both at initial repair (P = .01) and after 160 minutes of testing (P = .01). DBK had a significantly larger mean pressurized contact area than all the repairs after 160 minutes of testing (P = .01). DBK had a significantly larger post-cyclic loading pressurized contact area than CL (P = .01) and SR (P = .004) but not DR (P = .07). This study showed that a diamondback repair (a modification of the transosseous repair) can significantly increase the rotator cuff pressurized contact area in comparison with other standard rotator cuff repair constructs when there is sufficient tendon mobility to perform a double-row repair without excessive tension on the repair site. The persistent pressurized contact area of a DBK repair may be desirable to enhance healing potential when there is sufficient tendon mobility to perform a double-row repair, particularly for large or massive rotator cuff tears where it is important to optimize footprint area and contact to encourage biologic healing.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 02/2012; 28(2):188-95. · 3.02 Impact Factor
• Article: Biomechanical evaluation of classic solid and novel all-soft suture anchors for glenoid labral repair.

  Augustus D Mazzocca, David Chowaniec, Mark P Cote, Joel Fierra, John Apostolakos, Michael Nowak, Robert A Arciero, Knut Beitzel
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  ABSTRACT: To evaluate the biomechanical performance of an all-soft suture anchor (JuggerKnot; Biomet, Warsaw, IN) in comparison with a classic solid suture anchor (2.4-mm biocomposite SutureTak; Arthrex, Naples, FL) in an in vitro labral repair model. We dissected 12 cadaveric shoulders (mean age, 61 ± 9.4 years), leaving the labrum intact, and bone mineral density was obtained (mean, 0.375 ± 0.06 g/cm(3)). Simulated labral tears were made at the anteroinferior and posteroinferior edges of the labrum. Repairs used 2 all-soft suture anchors (JuggerKnot) or 2 solid anchors with free, high-strength No. 2 suture (FiberWire; Arthrex) spanning the operative construct to load the repair. Differential variable reluctance transducers were used to measure labral displacement for each specimen. The testing protocol consisted of a preconditioning phase at 10 N for 10 cycles (1 Hz) and then a final load-to-failure testing at a rate of 3 mm/min. Labral displacement of 2 mm was determined as the primary outcome. There was no statistical difference (P = .22) in ultimate load to failure and displacement at ultimate failure (anchor pullout) between the all-soft JuggerKnot (146.0 ± 43.0 N and 19.8 ± 5.4 mm, respectively) and the solid SutureTak (171.9 ± 52.6 N and 22.3 ± 6.8 mm, respectively). The solid anchor had a significantly higher ultimate load at 2 mm of labral displacement than the all-soft suture anchor (84.1 ± 19.0 N and 39.2 ± 10.6 N, respectively; P < .001). Whereas both the solid SutureTak and the all-soft JuggerKnot displayed similar results on ultimate load-to-failure testing, the solid anchor required significantly greater load for 2 mm of labral displacement than the all-soft anchor. The all-soft anchor (JuggerKnot) is similar in biomechanical performance to the classic solid anchor (SutureTak) with the exception of load at 2 mm of labral displacement, suggesting micromotion of the device.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 01/2012; 28(5):642-8. · 3.02 Impact Factor
• Article: Corticosteroids and local anesthetics decrease positive effects of platelet-rich plasma: an in vitro study on human tendon cells.

  Bradley Carofino, David M Chowaniec, Mary Beth McCarthy, James P Bradley, Steve Delaronde, Knut Beitzel, Mark P Cote, Robert A Arciero, Augustus D Mazzocca
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  ABSTRACT: To determine the effects of mixing anesthetics or corticosteroids with platelet-rich plasma (PRP) on human tenocytes in vitro. Two separate protocols (double spin and single spin) were used to obtain homologous PRP from the blood of 8 healthy volunteers. Discarded tendon acquired during biceps tenodesis served as tendon specimens for all experiments. After cell isolation, tenocytes were treated in culture with PRP alone or in combination with corticosteroids and/or anesthetics. Fetal bovine serum in concentrations of 2% and 10% served as controls. Cell exposure times of 5, 10, and 30 minutes were used. Radioactive thymidine and luminescence assays were obtained to examine cell proliferation and viability. The presence of lidocaine, bupivacaine, or methylprednisolone resulted in significantly less proliferation than the negative 2% fetal bovine serum control (P < .05). When we compared groups, both lidocaine and bupivacaine had a greater inhibitory effect than methylprednisolone (P < .05). At all time points, viability was significantly decreased in the presence of lidocaine, bupivacaine, or methylprednisolone compared with the negative control (P < .05). The addition of either anesthetics or corticosteroids to PRP resulted in statistically significant decreases in tenocyte proliferation and cell viability. These results suggest that incorporation of anesthetics or corticosteroids, either alone or in combination, with PRP injection may compromise the potentially beneficial in vitro effects of isolated PRP on tendon cells and compromise cell viability at the site of tendon injury. Anesthetics or corticosteroids either alone or in combination should be used carefully to preserve the proposed positive effects of PRP in the treatment of tendon injury.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 01/2012; 28(5):711-9. · 3.02 Impact Factor
• Article: Rapid isolation of human stem cells (connective progenitor cells) from the distal femur during arthroscopic knee surgery.

  Knut Beitzel, Mary Beth McCarthy, Mark P Cote, David Chowaniec, Lauryn M Falcone, Justine A Falcone, Evan M Dugdale, Thomas M Deberardino, Robert A Arciero, Augustus D Mazzocca
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  ABSTRACT: (1) To safely obtain bone marrow aspirates from the distal femur during arthroscopic knee surgery, (2) to purify and efficiently concentrate connective tissue progenitor cells (CTPs) in the operating room (OR), and (3) to confirm that these are CTPs through their ability to differentiate into bone cells. Bone marrow aspirates were harvested from the distal femur during arthroscopic knee surgery in 26 patients. Twenty-five matched control subjects were selected to evaluate for increased incidence of complications. CTPs were isolated using a rapid method designed for use in the OR compared with 2 accepted methods. Cytochemical and molecular analysis was used to assess osteogenic potential. Osteogenic potential of the CTPs was confirmed by reverse transcription polymerase chain reaction analysis and cellular staining. Bone marrow was successfully aspirated in 25 cases, with 3 incidences of stiffness in the aspirate group compared with 2 in the control group, 1 incidence of a wound irregularity in the aspirate group compared with 1 in the control group, and 3 incidences of hemarthrosis/persistent effusion in the aspirate group compared with 1 in the control group. The rate of complications for the aspirate group was 36% compared with 25% in the control group. Our intention was to develop a technique for extracting and purifying bone marrow so that the orthopaedic surgeon would have a simple, safe, and efficient process by which to isolate CTPs during arthroscopic knee surgery. This method of aspiration did not lead to a significant increase in complications. Further bone marrow aspirate was successfully purified in the OR, with only a slight increase in surgery time, and resulted in a fractionated layer rich with CTPs. These cells showed osteogenic potential, as evidenced by their osteoblastic differentiation. These CTPs may have future use in enhancing the incorporation of the graft into the bone. Level III, matched case-control study.
  Arthroscopy The Journal of Arthroscopic and Related Surgery 01/2012; 28(1):74-84. · 3.02 Impact Factor