Mark P. Cote

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.

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.

The Positive Effects of Different Platelet-Rich Plasma Methods on Human Muscle, Bone, and Tendon Cells

Background: 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. Purpose: To compare the effects of different PRP separation methods on human bone, muscle, and tendon cells in an in vitro model. Study Design: Controlled laboratory study. Methods: 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 (PRPLP), a single-spin process yielding high platelet and white blood cell concentrations (PRPHP), and a double-spin that produces a higher platelet concentration and lower white blood cell concentration (PRPDS). 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. Results: Addition of PRPLP to osteocytes, myocytes, and tenocytes significantly increased cell proliferation (P ≤ .05) compared with the controls. Adding PRPDS to osteoblasts and tenocytes increased cell proliferation significantly (P ≤ .05), but no significance was shown for its addition to myocytes. The addition of PRPHP significantly increased cell proliferation compared with the controls only when added to tenocytes (P ≤ .05). Osteoblasts: Proliferation was significantly increased by addition of PRPLP compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRPDS led to significantly increased proliferation compared with all controls, native blood, and PRPHP (P ≤ .05). Proliferation was significantly less when PRPHP was added compared with PRPDS (P ≤ .05). Myocytes: Proliferation was significantly increased by addition of PRPLP compared with native blood (P ≤ .05). Adding PRPHP or PRPDS to myocytes showed no significant increase in proliferation compared with the controls or the other separations. Tenocytes: Proliferation was significantly increased by addition of PRPLP compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRPDS showed a significant increase compared with the controls and native blood. For tenocytes, there was a significant increase (P ≤ .05) seen when PRPHP was added compared with the controls and native blood but not compared with the other separations. Conclusion: 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. Clinical Relevance: 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.

Rapid Isolation of Human Stem Cells (Connective Tissue Progenitor Cells) From the Proximal Humerus During Arthroscopic Rotator Cuff Surgery

Background: Bone-to-tendon healing in the shoulder can be unpredictable. Biologic augmentation, through the implementation of adult mesenchymal stem cells, may improve this healing process. Purpose: The purpose of this study was to (1) arthroscopically obtain bone marrow aspirates from the proximal humerus during rotator cuff repair, (2) purify and concentrate the connective tissue progenitor cells (CTPs) in the operating room efficiently, and (3)confirm these are stem cells through their ability to differentiate into bone cells. We hypothesize that CTPs can be quickly and efficiently isolated from bone marrow during arthroscopic surgery and that these cells are capable of osteogenesis. Study Design: Cohort study; Level of evidence, 3; and Descriptive laboratory study. Methods: Bone marrow aspirates were harvested through the anchor tunnel of the humeral head during arthroscopic rotator cuff repair in 23 patients. Twenty-three matched controls were selected from a clinical registry to evaluate for increased incidence of complication. Connective tissue progenitor cells were isolated using 2 accepted methods and compared with a novel, rapid method designed for use in the operating room. Osteogenic potential was assessed by cytochemical and molecular analysis. Results: Reverse transcription polymerase chain reaction analysis and cellular staining confirmed the osteogenic potential of these CTPs. There was no statistical significant difference in the Single Assessment Numeric Evaluation score (aspirate, 86.3 ± 10.5; control, 83.6 ± 15.1; P = .54), range of motion measures (postoperative external rotation: aspirate, 65.0° ± 20.4°; control, 62.5° ± 17.1°; P = .67; postoperative forward elevation: aspirate, 163.0° ± 30.6°; control, 145.7° ± 41.4°; P = .12), or postoperative strength measures between groups (median, 5; range, 4-5 in the aspirate group compared with median, 5; range, 4-5 in the control group; P > .05). Conclusion: Connective tissue progenitor cells can be safely and efficiently aspirated from the proximal humerus using the anchor tunnel created during arthroscopic rotator cuff surgery. These cells may play an important role in cell-based therapies involving rotator cuff repair. Clinical Relevance: We have established a reliable, reproducible protocol for isolating CTPs in the operating room. These cells may have the potential to enhance the healing process after rotator cuff repair.

Corticosteroids and Local Anesthetics Decrease Positive Effects of Platelet-Rich Plasma: An In Vitro Study on Human Tendon Cells

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 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. RESULTS 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). CONCLUSIONS 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. CLINICAL RELEVANCE 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.

Rehabilitation of acromioclavicular joint separations: operative and nonoperative considerations.

Acromioclavicular joint (AC) separations are one of the most common injuries seen in orthopedic and sports medicine practices, accounting for 9% of all injuries to the shoulder girdle. Various operative and nonoperative treatment schemes have been described for the management of AC joint injuries. Although there is controversy about the efficacy of surgical reconstruction versus nonoperative intervention for grade III type injuries, grade I and II separations seem to respond favorably to conservative management. Conversely, grades IV, V, and VI often require surgical reconstruction. Regardless of the type of injury, rehabilitation as a part of conservative management and postoperative care plays an important role in the management of these injuries. This article presents a rehabilitation approach to treatment of acromioclavicular separations pre- and postoperatively.

The Effect of a Combined Glenoid and Hill-Sachs Defect on Glenohumeral Stability A Biomechanical Cadaveric Study Using 3-Dimensional Modeling of 142 Patients

Background: Bone loss in anterior glenohumeral instability occurs on both the glenoid and the humerus; however, existing biomechanical studies have evaluated glenoid and humeral head defects in isolation. Thus, little is known about the combined effect of these bony lesions in a clinically relevant model on glenohumeral stability. Hypothesis/Purpose: The purpose of this study was to determine the biomechanical efficacy of a Bankart repair in the setting of bipolar (glenoid and humeral head) bone defects determined via computer-generated 3-dimensional (3D) modeling of 142 patients with recurrent anterior shoulder instability. The null hypothesis was that adding a bipolar bone defect will have no effect on glenohumeral stability after soft tissue Bankart repair. Study Design: Controlled laboratory study. Methods: A total of 142 consecutive patients with recurrent anterior instability were analyzed with 3D computed tomography scans. Two Hill-Sachs lesions were selected on the basis of volumetric size representing the 25th percentile (0.87 cm3; small) and 50th percentile (1.47 cm3; medium) and printed in plastic resin with a 3D printer. A total of 21 cadaveric shoulders were evaluated on a custom shoulder-testing device permitting 6 degrees of freedom, and the force required to translate the humeral head anteriorly 10 mm at a rate of 2.0 mm/s with a compressive load of 50 N was determined at 60° of glenohumeral abduction and 60° of external rotation. All Bankart lesions were made sharply from the 2- to 6-o’clock positions for a right shoulder. Subsequent Bankart repair with transosseous tunnels using high-strength suture was performed. Hill-Sachs lesions were made in the cadaver utilizing a plastic mold from the exact replica off the 3D printer. Testing was conducted in the following sequence for each specimen: (1) intact, (2) posterior capsulotomy, (3) Bankart lesion, (4) Bankart repair, (5) Bankart lesion with 2-mm glenoid defect, (6) Bankart repair, (7) Bankart lesion with 2-mm glenoid defect and Hill-Sachs lesion, (8) Bankart repair, (9) Bankart lesion with 4-mm glenoid defect and Hill-Sachs lesion, (10) Bankart repair, (11) Bankart lesion with 6-mm glenoid defect and Hill-Sachs lesion, and (12) Bankart repair. All sequences were used first for a medium Hill-Sachs lesion (10 specimens) and then repeated for a small Hill-Sachs lesion (11 specimens). Three trials were performed in each condition, and the mean value was used for data analysis. Results: A statistically significant and progressive reduction in load to translation was observed after a Bankart lesion was created and with the addition of progressive glenoid defects for each humeral head defect. For medium (50th percentile) Hill-Sachs lesions, there was a 22%, 43%, and 58% reduction in stability with a 2-, 4-, and 6-mm glenoid defect, respectively. For small (25th percentile) Hill-Sachs lesions, there was an 18%, 27%, and 42% reduction in stability with a 2-, 4-, and 6-mm glenoid defect, respectively. With a ≥2-mm glenoid defect, the medium Hill-Sachs group demonstrated significant reduction in translation force after Bankart repair (P < .01), and for the small Hill-Sachs group, a ≥4-mm glenoid defect was required to produce a statistical decrease (P < .01) in reduction force after repair. Conclusion: Combined glenoid and humeral head defects have an additive and negative effect on glenohumeral stability. As little as a 2-mm glenoid defect with a medium-sized Hill-Sachs lesion demonstrated a compromise in soft tissue Bankart repair, while small-sized Hill-Sachs lesions showed compromise of soft tissue repair with ≥4-mm glenoid bone loss. Clinical Relevance: Bipolar bony lesions of the glenoid and humeral head occur frequently together in clinical practice. Surgeons should be aware that the combined defects and glenoid bone loss of 2 to 4 mm or approximately 8% to 15% of the glenoid could compromise Bankart repair and thus may require surgical strategies in addition to traditional Bankart repair alone to optimize stability.

Rotational and Translational Stability of Different Methods for Direct Acromioclavicular Ligament Repair in Anatomic Acromioclavicular Joint Reconstruction

Background: Many reconstructions of acromioclavicular (AC) joint dislocations have focused on the coracoclavicular (CC) ligaments and neglected the functional contribution of the AC ligaments and the deltotrapezial fascia. Purpose: To compare the modifications of previously published methods for direct AC reconstruction in addition to a CC reconstruction. The hypothesis was that there would be significant differences within the variations of surgical reconstructions. Study Design: Controlled laboratory study. Methods: A total of 24 cadaveric shoulders were tested with a servohydraulic testing system. Two digitizing cameras evaluated the 3-dimensional movement. All reconstructions were based on a CC reconstruction using 2 clavicle tunnels and a tendon graft. The following techniques were used to reconstruct the AC ligaments: a graft was shuttled underneath the AC joint back from anterior and again sutured to the acromial side of the joint (group 1), a graft was fixed intramedullary in the acromion and distal clavicle (group 2), a graft was passed over the acromion and into an acromial tunnel (group 3), and a FiberTape was fixed in a cruciate configuration (group 4). Anterior, posterior, and superior translation, as well as anterior and posterior rotation, were tested. Results: Group 1 showed significantly less posterior translation compared with the 3 other groups (P < .05) but did not show significant differences compared with the native joint. Groups 3 and 4 demonstrated significantly more posterior translation than the native joint. Group 1 showed significantly less anterior translation compared with groups 2 and 3. Group 3 demonstrated significantly more anterior translation than the native joint. Group 1 demonstrated significantly less superior translation compared with the other groups and with the native joint. The AC joint of group 1 was pulled apart less compared with all other reconstructions. Only group 1 reproduced the native joint for the anterior rotation at the posterior marker. Group 4 showed significantly increased distances for all 3 measure points when the clavicle was rotated posteriorly. Conclusion: Reconstruction of the AC ligament by direct wrapping and suturing of the remaining graft around the AC joint (group 1) was the most stable method and was the only one to show anterior rotation comparable with the native joint. In contrast, the transacromial technique (group 3) showed the most translation and rotation. Clinical Relevance: An anatomic repair should address both the CC ligaments and the AC ligaments to control the optimal physiologic function (translation and rotation).

Sequential Resection of the Distal Clavicle and Its Effects on Horizontal Acromioclavicular Joint Translation

Background: Reconstructions of the coracoclavicular (CC) ligament in an open or arthroscopically assisted procedure are often combined with a resection of the distal clavicle to prevent or treat osteoarthritic degenerations of the acromioclavicular (AC) joint. However, increased horizontal translation leading to symptomatic instability may be associated with resection of the distal clavicle. Hypothesis: Horizontal translation increases in direct correlation to subsequent resection of the distal clavicle. Study Design: Controlled laboratory study. Methods: Twelve fresh-frozen specimens (mean age, 82.0 ± 5 years) were examined using a servohydraulic testing system. A 70-N force was applied in the anterior, posterior, and superior directions, and the translations were quantified for all directions. After native testing, sequential resection of the distal clavicle at 5 and 10 mm was performed after incision of the inferior capsule, and anterior-posterior loads were retested. Finally, the AC ligaments were incised, and repeated testing was performed. Results: Native mean (± standard deviation) anterior translation was 7.90 ± 2.62 mm. After section of the inferior AC capsule, anterior translation was 8.05 ± 2.62 mm (P = 1.0). After clavicle resection of 5 mm, anterior translation was 10.75 ± 2.38 mm (P = .122), and after resection of 10 mm, anterior translation was significantly increased to 11.6 ± 2.37 mm (P = .012). Complete AC capsule sectioning led to significantly greater amounts of anterior translation (12.12 ± 3.0 mm; P = .003). Posterior translation for the native specimen was 8.88 ± 2.63 mm. Sectioning of the inferior AC capsule resulted in 9.21 ± 2.71-mm translation (P = 1.0). After clavicle resection of 5 mm, posterior translation was 10.42 ± 2.42 mm (P = 1.0), and after 10-mm resection, it was 11.31 ± 2.86 mm (P = .39). Sectioning of the complete AC capsule led to significantly greater amounts of posterior translation (12.31 ± 3.12 mm; P = .043). Conclusion: Ten millimeters of resection increased anterior translation of the distal clavicle with both the superior and posterior AC capsules as well as the CC ligaments intact. Both anterior and posterior translations increased after 10-mm resection and complete AC capsule sectioning. Clinical Relevance: These results suggest that resection of the distal clavicle leads to increased horizontal translation despite an intact superior and posterior AC capsule. Only sparing resection of the distal clavicle should be performed and only if strictly indicated. Violation of the AC capsule further increases horizontal translation and should therefore be avoided, or if indicated in AC joint dislocations, a reconstruction of the AC capsule should be considered.