Corticosteroids and Local Anesthetics Decrease Positive Effectsof Platelet-Rich Plasma: An In Vitro Study on Human

Tendon Cells

Bradley Carofino, M.D., David M. Chowaniec, B.S., Mary Beth McCarthy, B.S.,James P. Bradley, M.D., Steve Delaronde, M.P.H., M.S.W., Knut Beitzel, M.D.,

Mark P. Cote, P.T., D.P.T., Robert A. Arciero, M.D., and Augustus D. Mazzocca, M.S., M.D.

Purpose: To determine the effects of mixing anesthetics or Corticosteroids with platelet-rich plasma(PRP) on human tenocytes in vitro. Methods: Two separate protocols (double spin and single spin)were used to obtain homologous PRP from the blood of 8 healthy volunteers. Discarded tendonacquired 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/oranesthetics. Fetal bovine serum in concentrations of 2% and 10% served as controls. Cell exposuretimes of 5, 10, and 30 minutes were used. Radioactive thymidine and luminescence assays wereobtained to examine cell proliferation and viability. Results: The presence of lidocaine, bupivacaine,or methylprednisolone resulted in significantly less proliferation than the negative 2% fetal bovineserum control (P < .05). When we compared groups, both lidocaine and bupivacaine had a greaterinhibitory effect than methylprednisolone (P < .05). At all time points, viability was significantlydecreased in the presence of lidocaine, bupivacaine, or methylprednisolone compared with thenegative control (P < .05). Conclusions: The addition of either anesthetics or Corticosteroids to PRPresulted in statistically significant decreases in tenocyte proliferation and cell viability. These resultssuggest that incorporation of anesthetics or Corticosteroids, either alone or in combination, with PRPinjection may compromise the potentially beneficial in vitro effects of isolated PRP on tendon cellsand compromise cell viability at the site of tendon injury. Clinical Relevance: Anesthetics orCorticosteroids either alone or in combination should be used carefully to preserve the proposedpositive effects of PRP in the treatment of tendon injury.

From the Department of Orthopaedic Surgery, University ofConnecticut Health Center (B.C., D.M.C., M.B.M., S.D., K.B.,M.P.C., R.A.A., A.D.M.), Farmington, Connecticut; and the Centerfor Sports Medicine, University of Pittsburgh Medical Center(J.P.B.), Pittsburgh, Pennsylvania, U.S.A.

The authors report the following potential conflict of interest orsource of funding in relation to this article: The University ofConnecticut Health Center/New England Musculoskeletal Institutehas received direct funding and material support for this studyfrom Arthrex Inc., Naples, FL.

Received February 22, 2011; accepted September 24, 2011.Address correspondence to Augustus D. Mazzocca, M.S., M.D.,

University of Connecticut, 263 Farmington Ave, Farmington, CT06030, U.S.A. E-mail: mazzocca@uchc.edu

© 2012 by the Arthroscopy Association of North America0749-8063/11130/$36.00doi:10.1016/j.arthro.2011.09.013

Conservative treatment of various tendinopathieshas historically involved local injections of cor-

ticosteroids or anesthetics.1 The results of these treat-ments are variable, with both positive and negativeeffects observed.1-2 Recent orthopaedic research hasfocused on platelet-rich plasma (PRP) for its potentialuse in the. treatment of various tendon injuries anddisorders.3'10 "PRP" is a generic term that refers toany sample of autologous plasma with platelet con-centrations above baseline blood values.11 PRP treat-ment is primarily intended to enhance the healingprocess through the secretion of various growth fac-tors.5

Literature regarding the clinical efficacy of PRPtreatment for tendon injuries is variable, with bothpositive and negative effects being reported in se-

Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 28, No 5 (May), 2012: pp 711-719 111

712 B. CAROFINO ET AL.

lected studies.4'6-12"17 Some of the recent literature hasfailed to show significant benefit with the applicationof PRP during surgical tendon repair.12-14 Conversely,Mishra et al.6-15 reported favorable results for PRPwhen compared with corticosteroids or local anesthet-ics for the treatment of epicondylitis. Peerbooms etal.16 reported similar findings in a double-blind ran-domized trial comparing PRP application with corti-costeroids. Applications of PRP for the treatment ofplantar fasciitis have also shown positive results.4-17

The emergence of PRP as a treatment option fortendon-related injury has led to clinicians providinginjections of platelet preparations in isolation and incombination with commonly used pharmaceuticals.The injection of PRP has been anecdotally noted to bepainful, prompting clinicians to add local anesthetics.PRP may enhance efficacy and improve treatmentoutcome. Furthermore, a combination of PRP andcorticosteroids may reduce the harmful effects of cor-ticosteroid injections.2 This potential effect has beenreported by Wong et al.,18 who described platelet-derived growth factor (PDGF) as a protective agentfor the negative effects of dexamethasone on culturedhuman tenocytes in an in vitro model.

To elucidate the effects of such combinations ofanesthetics and steroids with PRP, laboratory investi-gations conducted in a clinically applicable mannerare needed. Such investigations would require appli-cation of PRP to be matched to the donor tissue, tomeet the criteria of autologous treatment. This can bechallenging because it would require coordination ofintraoperative tissue harvesting, time needed for cellisolation/culture, and fresh plasma preparations at thetime of application. As a result, previous investigatorshave used homologous PRP in comparable experi-mental designs.18'22 As in these studies, the term"PRP" in our study refers to homologous plateletconcentrates. In addition, in vitro tenocyte modelshave been used to study the dose effects of pharma-ceuticals either in isolation or in combination.18 Theutilization of human tendon cells compared with ani-mal tendon cells in in vitro models is considered the"gold standard" for laboratory investigation.23

The purpose of this study was to determine invitro whether the addition of anesthetics or cortico-steroids, either alone or in combination, alters theeffects of PRP on human tenocytes. Our null hy-pothesis was that the addition of an anesthetic orcorticosteroid to 2 different types of PRP productswould have no detrimental effects on tenocyte pro-liferation or viability.

METHODS

Plasma Concentrates

Venous blood was collected from 8 healthy volun-teers (2 women and 6 men) with a mean age of 31.7 ±11.1 years (Institutional Review Board No. 10-204-2).To obtain PRP, 2 separate isolation protocols wereused: single spin (PRPSS) and double spin (PRPDS).These protocols were selected to reflect current clini-cal practice.3

PRPSS: The Arthrex Double Syringe (Arthrex, Na-ples, EL) was used for production of Autologous Con-ditioned Plasma (ACP; Arthrex). The Double Syringewas filled with 10 mL of blood to produce approxi-mately 3 mL of PRPSS. The syringe was centrifugedwith 1,500 rpm for 5 minutes. This separated theblood into 2 layers: plasma and the red and whiteblood cell layer containing erythrocytes and leuko-cytes. The plasma containing the platelets was thenisolated with the inner syringe.

PRPDS: A literature-based double-spin methodwas used to fractionate whole blood.20 After a firstcentrifugation of 1,500 rpm for 5 minutes, the plasmalayer was drawn up and was centrifuged a second time(20 minutes at 6,300 rpm). Finally, half of the super-ficial plasma layer was removed, and the platelet pel-let was suspended in the remaining half of the plasmavolume.

Corticosteroids and Local Anesthetics

Substances were selected with concentrations re-flecting our clinical practice: lidocaine (1%), bupiva-caine (0.5%), and methylprednisolone (40 mg/mL).Recognizing that surrounding body fluids quickly di-lute substances after an injection, diluted concentra-tions were used in an effort to replicate conditionsexperienced by tenocytes in vivo.24 In a 1-mL well,the following dilutions were used: 0.05 mL of lido-caine, 0.05 mL of bupivacaine, and 0.01 mL of meth-ylprednisolone.

Isolation of Tenocytes

Discarded biceps tendons were taken during bicepstenodesis from 4 different male donors (mean age,46.8 ± 4.2 years), and cells were isolated according topreviously described techniques (Institutional ReviewBoard No. 07-224).25 Tendons were cut into 3 X 3 X3-mm pieces and placed into 2% collagenase. Theresulting tenocyte cell suspension was filtered to re-move debris and cultured in Dulbecco's modified Ea-gle's medium (Invitrogen, Carlsbad, CA) containing

CORTICOSTEROIDS, LOCAL ANESTHETICS, AND PRP 713

10% fetal bovine serum (FBS) (Atlanta Biologicals,Atlanta, GA).25 All experiments were conducted usingcells within the first and second passages. Cells foreach experiment were taken from individual donors,thus representing a separate sample for each experi-ment. All experiments were repeated 4 times, eachwith a different donor.

Tenocyte Culture Experiments

Before the application of any treatment, tenocyteswere plated at a density of 10,000 cells per well. Todetermine the effects and interaction of the differenttreatments, several experimental groups were re-quired. A control was composed of isolated treatmentwith saline solution for identical application times andthen the treatment. To provide sufficient nourishmentto support cell viability without stimulating prolifera-tion, 2% FBS was selected for the proliferation exper-iment as an additional negative control. Two percentFBS keeps the cells in a very low proliferative stateand has no negative effects on the cells. For a positivecontrol, 10% FBS was chosen because it is known tosimulate cellular proliferation.25-27 Additional groupsconsisted of lidocaine (1%), bupivacaine (0.5%), andmethylprednisolone (40 mg/mL) and combinations of

lidocaine with methylprednisolone, as well as bupiv-acaine with methylprednisolone. For the experimentalgroups, tenocytes were treated in culture with eachPRP preparation (PRPDS and PRPSS) with or withoutthe addition of a local anesthetic or steroid. Thisresulted in experimental combinations that includedthe same combinations used in the control groups withthe addition of each PRP product. The complete ex-perimental setup is depicted in Fig 1.

Analysis of Cell Proliferation

A radioactive thymidine assay was used to measuretenocyte proliferation. Cells were plated and tenocyteswere treated (30 minutes) with saline solution, bothPRPs, lidocaine, bupivacaine, methylprednisolone, ora combination thereof as described earlier (Fig 1).After 4 days of culture, proliferating cells were la-beled with radioactive thymidine by adding 5.0 pcCi[3H] Thymidine/ml to each well for 24 hours.27 Afterlabeling of cells with radioactive thymidine, the fibrinclot commonly found was removed from each wellcontaining PRP to avoid assay interference and false-positive results. The radioactive thymidine was incor-porated into the DNA of dividing cells, and thereforean increase in radioactivity above the negative control

Control Treatment

Saline*

Lidocaine

Bupivacaine

Methylprednisolone

Lidocaine & Ivlethylpred.

Bupivacaine & Meihylpred.

Tenocyte culture

PRPs PRP,,

PRPss

f Lidocaine

* Bupivacaine

t Methylprednisolone

t Lidocaine & Methylpred.

* Bupivacaine & Methylpred.

PRPos

i- Lidocaine

f Bupivacaine

Methylprednisolone

t Lidocaine & Methylpred.

Buplvacafne & MeftMpred;; ." .'. *?•- -$P?^

1. Proliferation: Treatment for 30 minutes / cultured for 5 days2. Viability: treatmentfor 5,10,30 minutes / cultured for 24 hours

FIGURE 1. Flowchart showing experimental setup and treatment groups. Asterisk, as controls for the proliferation experiment, tenocyteswere plated in media containing 2% and 10% EBS; cells were plated in media containing 10% KBS as controls for the viability experiment.(Methylpred, methylprednisolone.)

714 B. CAROFINO ET AL.

directly correlates to cellular proliferation.27 To re-move unbound thymidine, cells were washed twicewith 10% trichloroacetic acid and then 0.5-mol/L so-dium hydroxide was added to the cells to release thenuclear-bound radioactive compound.27 The numberof proliferating cells was assayed by measuring thenumber of disintegrations per minute (dpm) with ascintillation counter. Only cells that had incorporatedthe radioactive thymidine were counted. Each wellwas measured in triplicate and reported as the mean toreduce the amount of variability.

Analysis of Cell Viability

Tenocytes were plated at a density of 15,000 cells perwell and cultured for 24 hours in 10% FBS beforeexperimentation.28 Cells were plated at a higher densityfor this experiment to facilitate the luminescence mea-surements described later. After 24 hours, the 10% FBSwas removed and the tenocytes were treated with PRP,lidocaine, bupivacaine, methylprednisolone, or a combi-nation thereof at the same concentrations that were testedin the tenocyte proliferation assay. Groups consisted oflidocaine (1%), bupivacaine (0.5%), and methylpred-nisolone (40 mg/mL) and combinations of lidocainewith methylprednisolone, as well as bupivacaine withmethylprednisolone. For the experimental groups,tenocytes were treated in culture with each PRP prep-aration (PRPDS and PRPSS) with or without the addi-tion of a local anesthetic or steroid. The cells wereexposed for 5, 10, and 30 minutes. These short timepoints were selected because pilot experiments usingidentical cell cultures showed that longer exposures (5days) resulted in 100% tenocyte death. Exposures of 1and 4 hours still showed cell death of approximately90%. In addition, little in vivo data exist on the localdistribution and absorption of local anesthetics. Otherauthors have also stated a rapid solution of PRP soonafter injection (minutes).20 However, a recent mag-netic resonance imaging study examining the localdistribution of anesthetics in oral surgery observed aclear reduction after 60 minutes and maximal finalabsorption times of 120 minutes.24

After the exposure period, the experimental mediawere removed and replaced with 10% FBS for a24-hour recovery prior to performing the viabilityassay. Cell viability was measured with a lumines-cence assay (CellTiter-Glo; Promega, Madison, WI).This assay produces a measurable luminescent signal,which is directly related to the amount of adenosinetriphosphate present in the well, and is proportional tothe number of viable cells. Each well was measured in

triplicate and reported as the mean to reduce theamount of variability. The number of viable tenocyteswas determined by creating a standard curve withknown concentrations (R2 range, 0.9023 to 0.9568).Luminescence values were transformed to obtain thenumber of viable cells:'Cell toxicity was determinedto be any number less than'the number obtained fromcells grown in the negative control (2% FBS).

Statistical Analysis

The Kolmogorov-Smirnov test was performed foreach experiment, and the mean skewness and kurtosiswere calculated and divided by the standard deviationto identify non-normal distributions. One-way analysisof variance was used to compare group means for ex-periments with normally distributed data followed byBonferroni post hoc tests for experiments with a statis-tically significant difference in means. The Kruskal-Wallis test was used to compare group means for exper-iments that had a non-normal data distribution even afterappropriate data transformations had been performed.For the Kruskal-Wallis tests, the Conover method wasused to calculate the P value for the critical differ-ence of the mean ranks. This allowed control forfamily-wise error. Experiments with a statisticallysignificant difference in means were followed bypost hoc tests. A P value (a level) of < .05 wasused to determine statistical significance. All statis-tical analyses were performed with SPSS software(IBM, Armonk, NY).

RESULTS

Plasma Concentrates

The preparation of platelets increased the plateletnumber in the PRPSS group on average to 2.6 timesthe baseline concentration of whole blood, whereasthe platelet number in the PRPDS group was on aver-age 3.3 times the concentration of whole blood. Whiteblood cell concentrations in both the PRPSS group andthe PRPDS group were decreased at least 10-fold incomparison with the concentration in whole bloodsamples (Table 1).

Analysis of Cell Proliferation

There were several significant findings among boththe control and experimental groups, as shown in Fig 2.With regard to the control groups (no PRP added),significant increases were observed in tenocyte prolif-eration in the 10% FBS (1,379 ± 543 dpm) in com-

CORTICOSTEROIDS, LOCAL ANESTHETICS, AND PRP 715

TABLE 1. Mean Concentrations of Blood Components (Platelets, Red Blood Cells, andWhite Blood Cells) in Native Blood and According to Separation Method

Product

Platelets (103//J,L)Red Blood Cells

Mean SD Mean SD

White Blood Cells(103/;U,L)

Mean SD

Blood

PRPssPRPDs

142.7361.5447.7

41.790.3S5.9

4.10.020.02

0.30.010.02

5.70.60.17

1.50.140.11

parison with the 2% FBS group (601 ± 141 dpm)(P < .05). The application of lidocaine, bupivacaine,or methylprednisolone each resulted in significantlyless proliferation when compared with the 2% FBScontrol (P < .05). When we compared lidocaine andbupivacaine, both resulted in significantly less teno-cyte proliferation than methylprednisolone (P < .05).There was no significant difference between the lido-caine and bupivacaine groups (Fig 2).

With regard to the experimental groups, bothpreparations of PRP (PRPSS and PRPDS) stimulatedtenocyte proliferation and each produced signifi-

cantly greater proliferation than both the negativecontrol (2% FBS) and positive control (10% FBS)(Fig 2). There was no significant difference betweenthe PRPSS and PRPDS groups.

All combinations of PRP with the addition of lido-caine, bupivacaine, and methylprednisolone to the me-dia either in isolation or in combination resulted insignificantly less tenocyte proliferation (P < .05).

PRPSS and methylprednisolone added to negative2% FBS control media (1,457 ± 475 dpm) resulted ingreater tenocyte proliferation when compared withPRPSS and lidocaine (188 ± 84 dpm) or PRPSS and

Tenocyte Proliferation

FIGURE 2. Graph showing tenocyte proliferation 5 days after treatment for 30 minutes. It should be noted that treatment with both PRPsincreased proliferation significantly and the combination of both PRPs and methylprednisolone showed results comparable to the controlgroups. Adding local anesthetics decreased tenocyte proliferation significantly for all isolated and combined groups. *P < .05. (M-Pred,methylprednisolone; Lido, lidocaine; Bupi, bupivacaine.)

716 B. CAROFINO ET AL.

bupivacaine (215 ± 72 dpm) (P < .05). PRPDS andmethylprednisolone added to negative 2% FBS con-trol media also showed significant increases in prolif-eration when compared with PRPDS and lidocaine orPRPDS and bupivacaine (P < .05). All 4 combinationsof the PRPs and anesthetics (PRPDS and lidocaine,PRPDS and bupivacaine, PPvPss and lidocaine, andPPvPss and bupivacaine) resulted in significant de-creases in proliferation when compared with the neg-ative 2% FBS control (P < .05) (Fig 2).

Analysis of Cell Viability

Cell viability, as detected by luminescence, isshown in Fig 2. After 10 and 30 minutes, viability wassignificantly decreased in the presence of lidocaine(P < .001 and P = .047, respectively), bupivacaine(P < .001 andP = .042, respectively), or methylpred-nisolone (P < .001 and P < .001, respectively) com-pared with saline solution. There were no significantdifferences in cell viability after 5 minutes of treat-ment when the anesthetics or methylprednisolone wasadded to PRP (PRPSS or PRPDS). At 10 and 30 min-utes, the addition of methylprednisolone (P = .05 forPRPSS and P = .013 for PRPDS) or bupivacaine (P =.001 for PRPSS and P = .009 for PRPDS) to either PRP(PRPSS or PRPDS) resulted in significantly decreasedviability compared with PRP (PRPSS or PRPDS) alone.The addition of lidocaine to both PRP preparations didnot significantly decrease viability at these time peri-ods (Table 2).

DISCUSSION

This study was designed to provide in vitro data toclinicians who are interested in combining PRP withanesthetics or corticosteroids. With regard to our hypoth-esis, tenocyte proliferation and viability were increasedwhen PRPSS and PRPDS preparations were added to the

tenocyte culture. Conversely, tenocyte proliferationand viability were substantially decreased when an-esthetics and corticosteroids were added. Combinedtreatment, using PRP preparations and anestheticsor corticoids, showed a decreased reaction com-pared with the isolated PRP treatment; however, itwas still increased compared with the isolated treat-ment with anesthetics, corticoids, or the combinationof anesthetics and corticoids.

Two different PRP preparations, single spin(PRPSS) and double spin (PRPDS), were used in thisstudy to control for effects possibly correlated to theproduction process of the PRP. For additions to PRP,we used commonly known and frequently used prod-ucts (lidocaine, bupivacaine, and . methylpred-nisolone).2'29'30 Lidocaine and bupivacaine are bothrepresentatives of amino amide-type local anesthetics;lidocaine has a quicker onset but a shorter duration ofaction than bupivacaine.30 Methylprednisolone is acommonly used synthetic glucocorticoid to decreaseinflammatory reactions.29-30 Although various prod-ucts exist for treatment of tendon injuries, these prod-ucts appear to be representative of our intended phar-macologic groups and are routinely used by the seniorauthor in his practice.30-31

With regard to model selection, human tenocytes(proximal long head of the biceps tendon) wereused in an effort to provide in vitro results that weremeaningful to clinicians using PRP as a treatmentfor tendon-related injury. Such 2-dimensional cellcultures allow for a very controlled evaluation ofthe treatment effects of pharmaceutics in a uniformenvironment.19'21 However, it should be regardedthat cultured tenocytes from different origins (e.g.,biceps and Achilles tendon) may react differentlyaccording to their harvesting site.18

Previous investigators have used similar in vitromodels to examine the effects of PRP on human

TABLE 2. Results of Viability Experiment According to Treatment and Time of Exposure to Treatment

ExposureAddition Time (min)

Lidocaine and Bupivacaine andSaline Solution Lidocaine Bupivacaine Methylprednisolone Methylprednisolone Methylprednisolone

None

PRPss

PRPos

510305

1030

51030

11,331.7 ± 3,619.917,299.2 ± 2,283.57,640.8 ± 2,089.5

14,389.0 ± 1,603.2' 12,152.2 ± 2,615.2

8,315.8 ± 622.618,375.0 ± 1,959.513,229.5 ± 2,338.29,046.1 ± 1,772.6

4,446.9 ± 520.23,153.0 ± 423.91,221.2 ± 879.7

16,010.4 ± 1,802.116,010.1 ± 1,801.316,010.8 ± 1,804.912,674.7 ± 791.113,306.0 ± 1,290.010,474.4 ± 627.5

2,278.2 ± 448.81,632.4 ± 870.0

882.8 ± 144.217,310.6 ± 1,400.56,993.8 ± 481.19,875.0 ± 812.9

17,373.2 ± 1,237.58,044.7 ± 3,308.1

10,363.5 ± 895.1

5,550.1 ± 1,450.33,350.1 ± 932.13,533.0 ± 1,007.2

12,137.1 ± 4,338.98,042.3 ± 2,992.04,799.4 ± 1,112.9

14,020.3 ± 3,415.82,992.0 ± 2,337.66,051.8 ± 859.1

1,889.6 ± 761.32,010.1 ± 324.51,087.1 ± 334.29,317.4 ± 1,249.16,888.6 ± 836.86,552.2 ± 318.2

12,235.7 ± 1,076.77,578.1 ± 370.29,123.2 ± 343.9

2,761.1 ± 625.51,258.1 ± 290.01,850.2 ± 600.6

14,765.9 ± 1,739.88,845.2 ± 1,012.29,374.6 ± 989.5

15,023.6 ± 2,187.29,168.2 ± 1,123.09,529.9 ± 720.0

NOTE. Data are presented as mean ± SD.

CORTICOSTEROIDS, LOCAL ANESTHETICS, AND PRP 717

tenocytes. Anitua et al.7>19 showed proliferation oftenocytes when cultured in PRP. De Mos et al.20 foundthat PRP stimulates increased total collagen produc-tion, cell proliferation, and expression of endogenousgrowth factors. Similar to these previous studies, teno-cytes treated in our study with PRP from either PRPSS

or PRPDS preparation resulted in statistically signifi-cant increases in tenocyte proliferation (P < .05)compared with the controls.

Conversely, the isolated treatment with lidocaineand bupivacaine resulted in significant decreases incell proliferation when compared with the controls(P < .05) or cells only treated with PRPSS and PRPDS.The observed inhibitory effect was greater with theapplication of the anesthetics. These results areconsistent with those of Scherb et al.,32 who alsoreported decreased human tenocyte proliferationand extracellular matrix production after treatmentwith bupivacaine, as well as Fedder et al.,33 whoshowed negative effects of treatment with lidocaine,bupivacaine, or ropivacaine on fibroblasts. Adverseeffects of anesthetics on a cellular level are notclearly understood. Local anesthetic solutions aregenerally prepared at a pH of 5.0 to 6.0, which maybe detrimental to treated cells due to the acidityalone.29

The reduction in tenocyte proliferation and via-bility observed after exposure to the methylpred-nisolone is also consistent with findings of otherinvestigators who reported decreases in tenocyteproliferation, viability, and collagen synthesis andincreases in markers of apoptosis.18-22'34'35 Theseeffects of glucocorticoids may be mediated throughglucocorticoid receptors in the cytoplasm of thetenocytes.36 Reports also exist on a decrease inproteoglycan production of tenocytes, an importantcomponent of the extracellular matrix, after treat-ment with corticoids.22 These findings may helpexplain previous reports of in vivo complicationsafter local corticosteroid application including ten-don rupture after corticoid injections.37-38

Considering the individual effects of anestheticsand corticoids, PRP preparations are yet not entirelyunderstood; it is difficult to anticipate the exact mech-anism for the improved results when combining thePRPs and the pharmaceuticals.18'21 One explanationfor the positive effect of combining PRP solutionswith local anesthetics may be seen in a bufferingeffect of the PRP solution, because amino amide so-lutions are slightly acidic. Despite significant de-creases, cells treated with PRP and methylpred-nisolone showed greater amounts of proliferation

when compared with cells treated with methylpred-nisolone alone. Wong et al.18 reported a comparablepreventive effect using a specific platelet-correlatedgrowth factor (PDGF) as a protective agent for thenegative effects of corticosteroid treatment on teno-cytes. Besides the positive effects of PDGF on viabil-ity and synthesis of tenocytes treated with corticoids,Zargar Baboldashti et al.21 recently showed protectiveeffects on tenocytes with the addition of PRP to cor-ticoids and antibiotics.18 The authors of that studydiscussed a protective effect of the PRP's growthfactors on the upregulation of stress response tran-scription factors, a cellular reaction attributed to cor-ticoid treatment.21 Such possible interactions of intra-cellular messenger signaling warrant evaluation infuture studies. Tenocytes are important for productionand maintenance of the tendon's extracellular matrix.Negative effects on tenocyte viability and prolifera-tion, and therefore decreases in matrix production,should be minimized to preserve tendon structure dur-ing treatment of tendon injuries.

There are several limitations of this study. The invitro behavior of biceps tendon cells may not mimicthe in vivo environment. Attempts were made to re-produce the complex in vivo conditions with our cellmodel; however, we were only able to estimate theconcentrations found in or around various tendons ofthe human body. This is primarily because of the widevariation of injection methods and doses used in aclinical setting.1'2'5'30-38 When considering evidence ofa dose-dependent effect, along with the possibility thatthe concentrations used were different from the un-known in vivo environment, the consistency in pro-portions permits conclusions regarding the relativeeffects of the investigated combinations.18 The heter-ogeneous nature of the blood and tissue samples mayhave impacted the study. Because the culruring andseparation of the tenocyte culture required severaldays and the possible storage time for PRP products isunknown, different donors had to be used to match theneeds for a controlled and structured experiment. Thissituation raises concern over a potential graft-versus-host reaction from incidental exposure of white bloodcells from one individual on the tendon to a differentindividual. This potential effect was likely minrmizedbecause up to 98% of white blood cells were elirnrnatedwith the PRPSS and PRPDS preparations. However, mul-tiple previous investigators have used homologous PRPin comparable experimental designs.18"22 Exposure timesof 5, 10, and 30 minutes were selected based on pilotdata and to simulate a high metabolic in vivo environ-ment (product's elimination half-life, dilution, and so on)

718 B. CAROFINO ET AL.

where body fluids can rapidly dilute injected sub-stances.20-24'29 This type of environment was believed tobe representative of common areas of tendon injury atthe time of injection.

CONCLUSIONS

The addition of either anesthetics or corticoste-roids to PRP resulted in statistically significant de-creases in tenocyte proliferation and cell viability.These results suggest that incorporation of anesthet-ics or corticosteroids, either alone or in combina-tion, with PRP injection may compromise the po-tentially beneficial in vitro effects of isolated PRPon tendon cells and compromise cell viability at thesite of tendon injury.

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13. Schepull T, Kvist J, Norrman H, Trinks M, Berlin G, Aspen-berg P. Autologous platelets have no effect on the healing ofhuman Achilles tendon ruptures: A randomized single-blindstudy. Am J Sports Med 2011;39:38-47.

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16. Peerbooms JC, Sluimer J, Bruijn DJ, Gosens T. Positive effectof an autologous platelet concentrate in lateral epicondylitis ina double-blind randomized controlled trial: Platelet-richplasma versus corticosteroid injection with a 1-year follow-up.Am J Sports Med 2010;38:255-262.

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CALL FOR COVER IMAGES!

You remember that interesting, unusual image from arecent procedure?

How about submitting it to the Journal for the cover?

See our Instructions for Authors for details and remember, we ask thatvideos accompany cover images.

Systematic Review With Video Illustration

The Role of Subacromial Decompression in Patients UndergoingArthroscopic Repair of Full-Thickness Tears of the Rotator

Cuff: A Systematic Review and Meta-analysis

Jaskarndip Chahal, M.D., F.R.C.S.C., Nathan Mall, M.D., Peter B. MacDonald, MX)., F.R.C.S.C.,Geoffrey Van Thiel, M.D., M.B.A., Brian J. Cole, M.D., M.B.A., Anthony A. Romeo, M.D., and

Nikhil N. Verma, M.D.

Purpose: The purpose of this study was to determine the efficacy of arthroscopic repair offull-thickness rotator cuff tears with and without subacromial decompression. Methods: We searchedthe Cochrane Central Register of Controlled Trials (third quarter of 2011), Medline (1948 to week 1 ofSeptember 2011), and Embase (1980 to week 37 of 2011) for eligible randomized controlled trials. Tworeviewers selected studies for inclusion, assessed methodologic quality, and extracted data. Pooledanalyses were performed by use of a random effects and relative risk model with computation of 95%confidence intervals. Results: We included 4 randomized trials and 373 patients. Methodologic qualitywas variable as assessed by the CLEAR NPT (Checklist to Evaluate a Report of a Non-pharmacologicalTrial) tool. One trial showed that there was no difference in disease-specific quality of life (WesternOntario Rotator Cuff questionnaire) between the 2 treatment groups. A meta-analysis of shoulder-specificoutcome measures (American Shoulder and Elbow Surgeons or Constant scores) or the rate of reoperationbetween patients treated with subacromial decompression and those treated without it also showed nostatistically significant differences. Conclusions: On the basis of the currently available literature, there isno statistically significant difference in subjective outcome after arthroscopic rotator cuff repair with orwithout acromioplasty at intermediate follow-up. Level of Evidence: Level I, systematic review of LevelI studies.

From the Division of Spans Medicine, Rush University MedicalCenter (J.C., N.M., G.V.T., B.J.C., A.A.R., N.N.V.), Chicago, Illi-nois, U.S.A.; and Pan Am Clinic, Division of Orthopaedic Surgery,Department of Surgery, University of Manitoba (P.B.M.), Winni-peg, Manitoba, Canada.

The authors report that they have no conflicts of interest in theauthorship and publication of this article.

Received October 16, 2011; accepted November 16, 2011.Address correspondence to Jaskarndip Chahal, M.D., F.R.S.C.S.,

SSS W^ Kinzie St, Chicago, IL 60654, U.S.A. E-mail: jaschahal®hotmail.com

© 2012 by the Arthroscopy Association of North America0749-8063/11675/$36.00doi:10.1016/j.arthro.2011.11.022

Note: To access the video accompanying this report, visit the Mayissue of Arthroscopy at www.arthroscopyjournal.org.

Since originally described by Neer in 1972,1 acro-mioplasties have become 1 of the most commonly

performed procedures in orthopaedic surgery.2 Theyare usually performed as part of a formal subacromialdecompression (SAD), which involves an anteroinfe-rior acromioplasty, coracoacromial ligament release,and subacromial bursectomy. In a population study byVitale et al.,2 the volume of acromioplasties (isolatedand combined with other procedures) in New YorkState increased by 254.4% over an 11-year period(1996 to 2006). Similarly, the mean number ofarthroscopic acromioplasties increased by 142.3%among candidates eligible for part 2 of their orthopae-dic surgery board certification examination over a10-year period (1999 to 2008). The most commonindication for an SAD remains subacromial impinge-ment with or without a concomitant rotator cuff tear.

fc

720 Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 28, No 5 (May), 2012: pp 720-727