R. Frank Henn

Site-Specific Targeting of Platelet-Rich Plasma via Superparamagnetic Nanoparticles

Background: Muscle strains are one of the most common injuries treated by physicians. Standard conservative therapy for acute muscle strains usually involves short-term rest, ice, and nonsteroidal anti-inflammatory medications, but there is no clear consensus regarding treatments to accelerate recovery. Recently, clinical use of platelet-rich plasma (PRP) has gained momentum as an option for therapy and is appealing for many reasons, most notably because it provides growth factors in physiological proportions and it is autologous, safe, easily accessible, and potentially beneficial. Local delivery of PRP to injured muscles can hasten recovery of function. However, specific targeting of PRP to sites of tissue damage in vivo is a major challenge that can limit its efficacy. Hypothesis: Location of PRP delivery can be monitored and controlled in vivo with noninvasive tools. Study Design: Controlled laboratory study. Methods: Superparamagnetic iron oxide nanoparticles (SPIONs) can be visualized by both magnetic resonance imaging (MRI) (in vivo) and fluorescence microscopy (after tissue harvesting). PRP was labeled with SPIONs and administered by intramuscular injections of SPION-containing platelets. MRI was used to monitor the ability to manipulate and retain the location of PRP in vivo by placement of an external magnet. Platelets were isolated from whole blood and incubated with SPIONs. Following SPION incubation with PRP, a magnetic field was used to manipulate platelet location in culture dishes. In vivo, the tibialis anterior (TA) muscles of anesthetized Sprague-Dawley rats were injected with SPION-containing platelets, and MRI was used to track platelet position with and without a magnet worn over the TA muscles for 4 days. Results: The method used to isolate PRP yielded a high concentration (almost 4-fold increase) of platelets. In vitro experiments showed that the platelets successfully took up SPIONs and then rapidly responded to an applied magnetic field. Platelets without SPIONs did not respond to the magnetic field. In vivo experiments showed that the SPION-containing platelets can be noninvasively maintained at a specific site with the application of a magnetic field. Conclusion: PRP may be a useful product in the clinical treatment of muscle injuries, but one problem with using it as a therapeutic tool is retaining PRP at the site of injury. This study proposes a potential solution, with findings that support this method at the cell, whole muscle, and in vivo levels. Controlling the location of PRP will allow the clustering of PRP to enrich the target area with growth factors and will prevent loss of platelets over time at the site of injury.

Subtalar release in clubfeet: a retrospective study of 10-year outcomes.

Background Optimal management of congenital talipes equinovarus continues to be controversial. There is a dramatically renewed emphasis on non-operative management partly because there has been a high recurrence rate among operated feet. Our hypothesis is that early, extensive subtalar ligament release as the cornerstone of aggressive hindfoot realignment prevents recurrence and retains mobility. Materials and Methods Twenty-two congenital clubfeet (14 patients) corrected by one surgeon were evaluated using two validated patient-based outcome instruments, dynamic pedobarographic analysis, hindfoot mobility, and weightbearing radiographs. Pedobarographic analysis consisted of quantifying peak plantar forces and pressures during the gait cycle in 22 corrected feet and 24 control feet using the FSCAN in-shoe device. Results The mean age at surgery was 8 months and mean followup was 10 years. No patients experienced recurrence of deformity. Reported foot function and satisfaction were very high for all patients and were comparable to reported normal population values. AP and lateral talocalcaneal angles for each foot were within normal limits for age. Hindfoot range of motion, including dorsiflexion, was preserved in all feet. Peak regional forces throughout the gait cycle and plantar pressures at foot flat were mildly, but statistically significantly, higher in the midfoot of corrected feet suggesting slight flattening of the arch. One patient had tendon transfers for bilateral calcaneal deformity and one patient had surgical correction of a bilateral valgus deformity. Conclusion Aggressive hindfoot realignment provides definitive treatment of an equinovarus deformity, but care must be taken to avoid overcorrection.

A Biomechanical Comparison of Allograft Tendons for Ligament Reconstruction

Background: Allograft tendons are frequently used for ligament reconstruction about the knee, but they entail availability and cost challenges. The identification of other tissues that demonstrate equivalent performance to preferred tendons would improve limitations. Hypothesis/Purpose: We compared the biomechanical properties of 4 soft tissue allograft tendons: tibialis anterior (TA), tibialis posterior (TP), peroneus longus (PL), and semitendinosus (ST). We hypothesized that allograft properties would be similar when standardized by the looped diameter. Study Design: Controlled laboratory study. Methods: This study consisted of 2 arms evaluating large and small looped-diameter grafts: experiment A consisted of TA, TP, and PL tendons (n = 47 each) with larger looped diameters of 9.0 to 9.5 mm, and experiment B consisted of TA, TP, PL, and ST tendons (n = 53 each) with smaller looped diameters of 7.0 to 7.5 mm. Each specimen underwent mechanical testing to measure the modulus of elasticity (E), ultimate tensile force (UTF), maximal elongation at failure, ultimate tensile stress (UTS), and ultimate tensile strain (UTε). Results: Experiment A: No significant differences were noted among tendons for UTF, maximal elongation at failure, and UTϵ. UTS was significantly higher for the PL (54 MPa) compared with the TA (44 MPa) and TP (43 MPa) tendons. E was significantly higher for the PL (501 MPa) compared with the TP (416 MPa) tendons. Equivalence testing showed that the TP and PL tendon properties were equivalent or superior to those of the TA tendons for all outcomes. Experiment B: All groups exhibited a similar E. UTF was again highest in the PL tendons (2294 N) but was significantly different from only the ST tendons (1915 N). UTϵ was significantly higher for the ST (0.22) compared with the TA (0.19) and TP (0.19) tendons. Equivalence testing showed that the TA, TP, and PL tendon properties were equivalent or superior to those of the ST tendons. Conclusion: Compared with TA tendons, TP and PL tendons of a given looped diameter exhibited noninferior initial biomechanical strength and stiffness characteristics. ST tendons were mostly similar to TA tendons but exhibited a significantly higher elongation/UTϵ and smaller cross-sectional area. For smaller looped-diameter grafts, all tissues were noninferior to ST tendons. In contrast to previous findings, PL tendons proved to be equally strong. Clinical Relevance: The results of this study should encourage surgeons to use these soft tissue allografts interchangeably, which is important as the number of ligament reconstructions performed with allografts continues to rise.

Os acromiale fixation: a biomechanical comparison of polyethylene suture versus stainless steel wire tension band

BACKGROUND Symptomatic hardware is a commonly reported complication after surgical fixation of an unstable meso-type os acromiale. This study compared the biomechanical properties of a cannulated screw tension band construct using a metal wire tension band vs. a suture tension band, considering that the suture construct could allow for decreased hardware burden in the clinical setting. METHODS A meso-type os acromiale was created in 16 cadaveric shoulders. Two cannulated 4-mm screws were placed in each specimen. Tension band augmentation was accomplished with a 1-mm stainless steel wire (wire group) or a #5 braided polyethylene suture (suture group), with 8 specimens in each group. An inferiorly directed force was applied to the anterior acromion at 1 mm/s on a materials testing machine. Stiffness and ultimate failure load were recorded and analyzed. RESULTS No significant difference (P = .22) was observed in the ultimate failure load between the wire (228  ± 85 N; range, 114-397 N) and the suture (275 ± 139 N; range, 112-530 N). No significant difference (P = .17) was observed in the stiffness between the wire (28  ± 12 N/mm; range, 18-53 N/mm) and the suture (38  ± 25 N/mm; range, 10-83 N/mm). CONCLUSIONS Stainless steel wire and polyethylene suture have similar biomechanical strength in the cannulated screw tension band fixation of meso-type os acromiale at time zero.

Patients’ Use and Perception of Internet-Based Orthopaedic Sports Medicine Resources

Background: Current research is sparse regarding how patients with orthopaedic injuries perceive and use internet-based information resources. Hypothesis: The majority of patients use the internet to research their orthopaedic condition and are receptive to guidance from their provider. Study Design: Cross-sectional study. Methods: A total of 213 patients attending a sports medicine clinic on the East Coast of the United States were asked to complete a questionnaire regarding their use of internet-based information. Data from 185 patients were available for analysis. Bivariate and multivariate statistical analyses were used to determine the significance of identified associations. Results: Overall, 54% of patients used the internet to find information about their orthopaedic condition prior to their consultation. A higher percentage of internet users were women (P = .01), were white (P = .03), and had internet access at home (P = .02). Multivariable analysis found home internet access to be the only significant independent factor predictive of patients using internet-based information sources (P < .01). The majority of patients (61%) were neutral toward orthopaedic information found online, and only 32% of patients trusted the orthopaedic information they found online. The majority of patients (83%) reported they would be receptive to providers’ guidance on which internet resources to use. Conclusion: Only half of patients use the internet to research their orthopaedic condition. Most patients were either neutral toward or did not trust the internet-based information that they found and may forgo internet sources altogether. To help patients avoid misleading information, sports medicine providers should understand how patients are using the internet and guide patients in selecting high-quality, peer-reviewed sources of information. Doing so allows physicians to proactively educate their patients even after the clinic visit.

Unicompartmental knee arthroplasty for spontaneous osteonecrosis of the knee: A meta-analysis

Background: Spontaneous osteonecrosis of the knee (SONK) is a poorly understood but debilitating disease entity. Total knee arthroplasty (TKA) is the standard of care for those patients who fail conservative management, but considering SONK’s predilection for affecting a single knee compartment, unicompartmental knee arthroplasty (UKA) appears to be a more tailored option. Unfortunately, conflicting data exist on the utility of UKA in SONK. Thus, the purpose of this study was to evaluate functional outcomes and revision rates of UKA in the setting of SONK. Methods: A systematic literature search was performed to evaluate all studies examining patients who underwent UKA for SONK. Screening of the articles was performed using multiple Boolean search strings, methodological index for non-randomized studies criteria, and other selected exclusion criteria. Results: Seven studies were included, with a total of 276 knees (273 patients). The mean age was 68 years (64–74 years), with a mean body mass index of 26 kg/m2 (25–29 kg/m2). The final range of motion was 125° (124–126°). Standardized mean difference (SMD) of clinical improvement pre- and post-outcome was 3.39 (p < 0.001). The improvement in the visual analog score was 57.03 points, with an SMD of 4.57 (p < 0.001). Revision rates were determined to be 5.51% (95% confidence interval of 1.96–10.69%). Conclusion: Our meta-analysis demonstrated that in properly selected patients, UKA could be an excellent alternative to TKA for patients with SONK. These data show that UKA has few complications, significant improvements on functional outcomes, and good survivorship at a mean follow-up of 6 years.

Effect of preoperative patient expectations on outcomes after reverse total shoulder arthroplasty

BACKGROUND The purpose of this study was to determine the effect of preoperative expectations on outcomes after reverse shoulder arthroplasty (RSA). We hypothesized that patients with greater expectations would have better outcomes. METHODS Patients undergoing primary RSA completed the Hospital for Special Surgerys Shoulder Expectations Survey preoperatively. Preoperative and 2-year postoperative clinical outcomes were measured with the American Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment Form, Shoulder Activity Scale (SAS), 36-Item Short Form Health Survey (SF-36), and visual analog scales (VASs). Pearson correlations were used to assess the relationship between the number of expectations and outcomes. Differences in outcomes between those with higher and lower levels of expectations for each expectation question were assessed by independent samples t test. Multivariable linear regression analysis was used to control for potential confounding factors. RESULTS We evaluated 135 patients at 2 years postoperatively. Patients had higher expectations for relieving pain, improving self-care, improving ability to perform daily activities, and improving ability to drive or put on a seatbelt. Patients with a greater number of high expectations preoperatively did not have better ASES, SAS, or VAS pain scores postoperatively. However, higher expectations for relieving nighttime pain was associated with ASES (β = 7.0, P = .048) and VAS pain scores (β = -5.9, P = .047) as well as 2-year improvement of VAS pain (β = -6.1, P = .039). Higher expectations for improving the ability to participate in nonoverhead sports was associated with improvements in SAS (β = 2.8, P = .020). CONCLUSION A higher level of expectations for relief of nighttime pain and improving ability to participate in nonoverhead sports is associated with improved outcomes after RSA.

Neer Award 2018: Benzoyl peroxide effectively decreases preoperative Cutibacterium acnes shoulder burden: a prospective randomized controlled trial

BACKGROUND Benzoyl peroxide (BPO) solutions effectively reduce Cutibacterium acnes (formerly Propionibacterium acnes) on the face, neck, and back in nonoperative settings. This study compared preoperative application of BPO vs. chlorhexidine gluconate (CHG) in decreasing shoulder C acnes skin burden in surgical patients. METHODS Eighty patients undergoing shoulder surgery were prospectively enrolled in a randomized double-blind trial at 1 institution from August 2015 to April 2017. Participants were randomized to 5% BPO or 4% CHG for 3 consecutive days. The nonoperative shoulder had no intervention and served as the negative control. Skin cultures of both shoulders were obtained via a detergent scrub technique the day of surgery at anterior, lateral, and posterior sites and the axilla. RESULTS Fewer positive cultures were obtained from the BPO-treated side compared with the contralateral side (P = .0003), and no change was shown for the CHG group (P = .80). Shoulders treated with BPO showed a statistically significant reduction in C acnes counts compared with CHG at anterior (P = .03) and posterior (P = .005) portal sites. No significant difference was found at the axilla (P = .99) or lateral portal site (P = .08). No postoperative infections or wound complications occurred in either group. CONCLUSIONS BPO is more effective than CHG at reducing C acnes on the shoulder. Decreasing the skin burden of C acnes may reduce intraoperative wound contamination and postoperative infection. BPO should be considered as an adjunctive preoperative skin preparation considering its potential benefit, low risk, and low cost.

Preoperative Opioid Use in Knee Surgery Patients

A cross-sectional analysis of data derived from patients undergoing knee surgery at a single institution was conducted. The objectives of the study were to determine the demographic, diagnostic, and psychologic factors associated with opioid use; and to determine the clinical correlates of opioid use. We hypothesized that preoperative opioid use would be associated with worse patient-reported outcome (PRO) measures. The sample consisted of 383 patients undergoing knee surgery. The patients were classified as either opioid or nonopioid users on the basis of medical record review. All participants completed a battery of clinical assessments, including the Patient-Reported Outcomes Measurement Information System computer adaptive testing in six domains: Physical Function, Pain Interference, Fatigue, Social Satisfaction, Anxiety, and Depression. Analyses were conducted to examine clinical variables as a function of opioid use. The results indicated that opioid use was associated with female gender, unemployment, smoking, higher American Society of Anesthesiologists scores, greater number of previous surgeries, depression or anxiety, and worse expectation of surgery (p < 0.05). Multivariable analysis found opioid use to be a significant independent predictor of multiple PRO measures in patients undergoing knee surgery. Potential explanations for these findings are presented, and clinical implications are discussed.

How Should We Secure Our Transplanted Meniscus? A Meta-analysis:

Background: Meniscal allograft transplant (MAT) is a salvage procedure for young patients with symptomatic meniscal deficiency. Although many studies report good outcomes, MAT remains controversial, and an optimal fixation technique for the meniscus roots is debated. Purpose: To assess the overall outcome of MAT and compare the results of different meniscal root fixation techniques. Study Design: Meta-analysis. Methods: Following specific guidelines, we systematically evaluated all current literature for studies reporting on the outcomes of patients who underwent MAT. Using random effect models of proportions, we determined the tear and failure rates. Standardized mean differences (SMDs) were calculated to determine the improvement in clinical outcomes and pain level. Data were then stratified by root fixation method into 2 groups: fixation that preserved the graft’s root insertions on the allograft bone (bone fixation group) and suture fixation of the root soft tissue without the allograft bone (soft tissue suture group). Results: A total of 38 studies (1637 MATs, 81% men) involving subjects with a mean age of 34 years (range, 20-48 years) and a mean follow-up of 60 months (range, 25-168 months) met inclusion criteria. This overall cohort had significant improvements in Lysholm scores (from 57.8 to 81.4 points; SMD 1.5, P < .001) and pain level (visual analog scale [VAS], from 56 to 21 points; SMD 1.8, P < .001). The cohort had a tear rate of 9% and a failure rate of 12.6%. No significant differences were found between the soft tissue suture (485 MATs) and bone fixation (489 MATs) groups in terms of meniscal allograft tear rates (13.4% vs 14.9%), failure rates (17.6% vs 18.8%), Lysholm scores (from 52.3 to 82.4, SMD 2.0, and from 60.7 to 82.9, SMD 1.7; respectively), and VAS scores (from 65 points to 18 points, SMD 2.6, and from 63 points to 13 points, SMD 3.1; both P < .001). Meniscal extrusion was similar, with a weighted mean percentage of extrusion of 40.2% in the soft tissue suture group and 43.1% in the bone fixation group. Conclusion: This meta-analysis demonstrated significant improvements in clinical outcomes for MAT patients with low tear and failure rates. The data do not demonstrate a difference between soft tissue suture and bone fixation for MAT root fixation. This suggests that the technique of root fixation may not have an appreciable influence on clinical outcome, pain reduction, extrusion, or MAT longevity. Further prospective trials are needed.