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Dive into the research topics where John W. Belk is active.

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Featured researches published by John W. Belk.


American Journal of Sports Medicine | 2018

Microfracture Versus Autologous Chondrocyte Implantation for Articular Cartilage Lesions in the Knee: A Systematic Review of 5-Year Outcomes:

Matthew J. Kraeutler; John W. Belk; Justin M. Purcell; Eric C. McCarty

Background: Microfracture (MFx) and autologous chondrocyte implantation (ACI) are 2 surgical treatment options used to treat articular cartilage injuries of the knee joint. Purpose: To compare the midterm to long-term clinical outcomes of MFx versus ACI for focal chondral defects of the knee. Study Design: Systematic review. Methods: A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to locate studies (level of evidence I-III) comparing the minimum average 5-year clinical outcomes of patients undergoing MFx versus ACI. Search terms used were “knee,” “microfracture,” “autologous chondrocyte implantation,” and “autologous chondrocyte transplantation.” Patients were evaluated based on treatment failure rates, magnetic resonance imaging, and patient-reported outcome scores (Lysholm, Knee Injury and Osteoarthritis Outcome Score [KOOS], and Tegner scores). Results: Five studies (3 level I evidence, 2 level II evidence) were identified that met the inclusion criteria, including a total of 210 patients (211 lesions) undergoing MFx and 189 patients (189 lesions) undergoing ACI. The average follow-up among all studies was 7.0 years. Four studies utilized first-generation, periosteum-based ACI (P-ACI), and 1 study utilized third-generation, matrix-associated ACI (M-ACI). Treatment failure occurred in 18.5% of patients undergoing ACI and 17.1% of patients undergoing MFx (P = .70). Lysholm and KOOS scores were found to improve for both groups across studies, without a significant difference in improvement between the groups. The only significant difference in patient-reported outcome scores was found in the 1 study using M-ACI in which Tegner scores improved to a significantly greater extent in the ACI group compared with the MFx group (P = .003). Conclusion: Patients undergoing MFx or first/third-generation ACI for articular cartilage lesions in the knee can be expected to experience improvement in clinical outcomes at midterm to long-term follow-up without any significant difference between the groups.


Knee Surgery, Sports Traumatology, Arthroscopy | 2018

Similar clinical outcomes following collagen or polyurethane meniscal scaffold implantation: a systematic review

Darby A. Houck; Matthew J. Kraeutler; John W. Belk; Eric C. McCarty; Jonathan T. Bravman

PurposeThe purpose of this systematic review is to evaluate the current literature in an effort to assess specific clinical outcomes following meniscal scaffold implantation using the two available scaffolds: Collagen Meniscal Implant (CMI) and the Actifit polyurethane meniscal scaffold.MethodsA systematic review was performed by searching PubMed, Embase, and Cochrane Library to find studies evaluating clinical outcomes of patients undergoing meniscal scaffold implantation. Search terms used were “meniscus”, “meniscal”, “scaffold”, and “implant”. Studies were evaluated based on scaffold type, treatment failure rates, patient-reported outcome scores, concomitant procedures, and radiological findings. Radiological findings were recorded using the Genovese scale to assess morphology and signal intensity and the Yulish score to assess articular cartilage.ResultsNineteen studies (1 level I, 1 level II, 17 level IV evidence) were identified that met inclusion criteria, including a total of 658 patients (347 Actifit, 311 CMI). The overall average follow-up was 45 months. Treatment failure occurred in 9.9% of patients receiving the Actifit scaffold at a mean follow-up of 40 months and 6.7% of patients receiving CMI at a mean follow-up of 44 months (n.s.). However, the rate of failure ranged from 0 to 31.8% amongst the included studies with a variable definition of failure. Additionally, overlapping patients and presence of concomitant surgeries such as anterior cruciate ligament reconstruction (ACLR) and high tibial osteotomy (HTO) may have a significant influence on these results. Outcomes for the Visual Analog Scale (VAS) for pain, Lysholm knee score, and Tegner activity score improved from preoperatively to latest follow-up in both groups, while the Knee Injury and Osteoarthritis Outcome Score and International Knee Documentation Committee scores improved from preoperatively to latest follow-up for Actifit scaffold patients. Overall, patients receiving CMI scaffolds had higher grades for Genovese morphology and signal intensity when compared to Actifit scaffold patients.ConclusionPatients undergoing meniscal scaffold implantation with either CMI or Actifit scaffold can both be expected to experience improvement in clinical outcomes when used in association with concomitant procedures such as ACLR and HTO.Level of evidenceIV, systematic review.


American Journal of Sports Medicine | 2018

Autograft Versus Allograft for Posterior Cruciate Ligament Reconstruction: An Updated Systematic Review and Meta-analysis:

John W. Belk; Matthew J. Kraeutler; Justin M. Purcell; Eric C. McCarty

Background: Multiple studies have demonstrated a higher risk of graft failure after anterior cruciate ligament reconstruction with allograft, but limited data are available comparing outcomes of posterior cruciate ligament reconstruction (PCLR) with autograft versus allograft. Purpose: To compare the clinical outcomes of autograft versus allograft for primary PCLR. Study Design: Systematic review. Methods: A systematic review was performed by searching PubMed, the Cochrane Library, and EMBASE to locate studies (level of evidence I-III) comparing clinical outcomes of autograft versus allograft in patients undergoing primary PCLR with the conventional transtibial technique. Search terms used were “posterior cruciate ligament,” “autograft,” and “allograft.” Patients were evaluated based on graft failure rate, examination of knee laxity, and patient-reported outcome scores (Lysholm, Tegner, subjective International Knee Documentation Committee [IKDC], and objective IKDC scores). Results: Five studies (2 level II, 3 level III) were identified that met inclusion criteria, including a total of 132 patients undergoing PCLR with autograft (semitendinosus-gracilis or bone–patellar tendon–bone) and 110 patients with allograft (tibialis anterior, Achilles tendon, or bone–patellar tendon–bone). No patients experienced graft failure. Average anteroposterior (AP) knee laxity was significantly higher in allograft patients (3.8 mm) compared with autograft patients (3.1 mm) (P < .01). Subjective IKDC, Lysholm, and Tegner scores improved for both groups across studies, without a significant difference in improvement between groups except in one study, in which Lysholm scores improved to a significantly greater extent in the autograft group (P < .01). Conclusion: Patients undergoing primary PCLR with either autograft or allograft can be expected to experience improvement in clinical outcomes. Autograft patients experienced less AP knee laxity postoperatively, although the clinical significance of this is unclear and subjective outcomes improved substantially and to a similar degree in both groups.


Orthopaedic Journal of Sports Medicine | 2017

The Effect of the Number of Carries Among College Running Backs on Future Injury Risk and Performance in the National Football League

Matthew J. Kraeutler; John W. Belk; Eric C. McCarty

Background: There has been speculation that running backs with an excessive number of carries in college are less likely to be successful in the National Football League (NFL). Purpose: To determine whether there is a correlation between number of carries by college running backs and future performance and injury risk in the NFL. Study Design: Cohort study; Level of evidence, 3. Methods: Using the ESPN archives of National Collegiate Athletic Association and NFL running backs, the following inclusion criteria were used: running backs who played their last college season from 1999 through 2012 and who were drafted in the first 4 rounds of the NFL draft following their college career. Players were grouped by number of carries during their final college season (group A, 100-200 carries; group B, 250+ carries). Performance and injury risk were compared between groups during the first 3 eligible seasons in the NFL. Groups were compared based on total number of carries, mean yards per carry, number of games missed due to injury, and the specific injuries resulting in missed playing time. Results: During the seasons studied, a total of 103 running backs were included (group A, n = 42; group B, n = 61). There was a trend toward a significantly greater mean total number of carries through 3 NFL seasons in group B (group A, n = 276 carries; group B, n = 376 carries; P = .058). Mean yards per carry did not differ between groups (group A, n = 3.9 yards/carry; group B, n = 4.0 yards/carry; P = .67). Groups A and B missed a mean 5.8 and 5.7 games, respectively, due to injury during their first 3 NFL seasons (P = .98). A significantly greater proportion of players in group A suffered a concussion compared with group B (P = .014). Conclusion: There is no correlation between the number of carries by college running backs and future injury risk or performance during their early NFL career.


Orthopaedic Journal of Sports Medicine | 2017

The Effect of Regular-Season Rest on Playoff Performance Among Players in the National Basketball Association

John W. Belk; Hayden A. Marshall; Eric C. McCarty; Matthew J. Kraeutler

Background: There has been speculation that rest during the regular season for players in the National Basketball Association (NBA) improves player performance in the postseason. Purpose: To determine whether there is a correlation between the amount of regular-season rest among NBA players and playoff performance and injury risk in the same season. Study Design: Cohort study; Level of evidence, 3. Methods: The Basketball Reference and Pro Sports Transactions archives were searched from the 2005 to 2015 seasons. Data were collected on players who missed fewer than 5 regular-season games because of rest (group A) and 5 to 9 regular-season games because of rest (group B) during each season. Inclusion criteria consisted of players who played a minimum of 20 minutes per game and made the playoffs that season. Players were excluded if they missed ≥10 games because of rest or suspension or missed ≥20 games in a season for any reason. Matched pairs were formed between the groups based on the following criteria: position, mean age at the start of the season within 2 years, regular-season minutes per game within 5 minutes, same playoff seeding, and player efficiency rating (PER) within 2 points. The following data from the playoffs were collected and compared between matched pairs at each position (point guard, shooting guard, forward/center): points per game, assists per game, PER, true shooting percentage, blocks, steals, and number of playoff games missed because of injury. Results: A total of 811 players met the inclusion and exclusion criteria (group A: n = 744 players; group B: n = 67 players). Among all eligible players, 27 matched pairs were formed. Within these matched pairs, players in group B missed significantly more regular-season games because of rest than players in group A (6.0 games vs 1.3 games, respectively; P < .0001). There were no significant differences between the groups at any position in terms of points per game, assists per game, PER, true shooting percentage, blocks, steals, or number of playoff games missed because of injury. Conclusion: Rest during the NBA regular season does not improve playoff performance or affect the injury risk during the playoffs in the same season.


Orthopaedic Journal of Sports Medicine | 2017

The Effect of the Number of Carries on Injury Risk and Subsequent Season’s Performance Among Running Backs in the National Football League

Matthew J. Kraeutler; John W. Belk; Eric C. McCarty

Background: In recent years, several studies have correlated pitch count with an increased risk for injury among baseball pitchers. However, no studies have attempted to draw a similar conclusion based on number of carries by running backs (RBs) in football. Purpose: To determine whether there is a correlation between number of carries by RBs in the National Football League (NFL) and risk of injury or worsened performance in the subsequent season. Study Design: Cohort study; Level of evidence, 3. Methods: The ESPN NFL statistics archives were searched from the 2004 through 2014 regular seasons. During each season, data were collected on RBs with 150 to 250 carries (group A) and 300+ carries (group B). The following data were collected for each player and compared between groups: number of carries and mean yards per carry during the regular season of interest and the subsequent season, number of games missed due to injury during the season of interest and the subsequent season, and the specific injuries resulting in missed playing time during the subsequent season. Matched-pair t tests were used to compare changes within each group from one season to the next in terms of number of carries, mean yards per carry, and games missed due to injury. Results: During the seasons studied, a total of 275 RBs were included (group A, 212; group B, 63). In group A, 140 RBs (66%) missed at least 1 game the subsequent season due to injury, compared with 31 RBs (49%) in group B (P = .016). In fact, players in group B missed significantly fewer games due to injury during the season of interest (P < .0001) as well as the subsequent season (P < .01). Mean yards per carry was not significantly different between groups in the preceding season (P = .073) or the subsequent season (P = .24). Conclusion: NFL RBs with a high number of carries are not placed at greater risk of injury or worsened performance during the subsequent season. These RBs may be generally less injury prone compared with other NFL RBs.


Orthopaedic Journal of Sports Medicine | 2018

Is Delayed Weightbearing After Matrix-Associated Autologous Chondrocyte Implantation in the Knee Associated With Better Outcomes? A Systematic Review of Randomized Controlled Trials:

Matthew J. Kraeutler; John W. Belk; Trevor J. Carver; Eric C. McCarty

Background: Proper rehabilitation after matrix-associated autologous chondrocyte implantation (MACI) is essential to restore a patient’s normal function without overloading the repair site. Purpose: To evaluate the current literature to assess clinical outcomes of MACI in the knee based on postoperative rehabilitation protocols, namely, the time to return to full weightbearing (WB). Study Design: Systematic review; Level of evidence, 1. Methods: A systematic review was performed to locate studies of level 1 evidence comparing the outcomes of patients who underwent MACI with a 6-week, 8-week, or 10/11-week time period to return to full WB. Patient-reported outcomes assessed included the Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner activity scale, Short Form Health Survey–36 (SF-36), and visual analog scale (VAS) for pain frequency and severity. Results: Seven studies met the inclusion criteria, including a total of 136 patients (138 lesions) who underwent MACI. Treatment failure had occurred in 0.0% of patients in the 6-week group, 7.5% in the 8-week group, and 8.3% in the 10/11-week group at a mean follow-up of 2.5 years (P = .46). KOOS, SF-36, and VAS scores in each group improved significantly from preoperatively to follow-up (P < .001). Conclusion: Patients undergoing MACI in the knee can be expected to experience improvement in clinical outcomes with the rehabilitation protocols outlined in this work. No significant differences were seen in failure rates based on the time to return to full WB.


Orthopaedic Journal of Sports Medicine | 2018

Do Focal Chondral Defects of the Knee Increase the Risk for Progression to Osteoarthritis? A Review of the Literature

Darby A. Houck; Matthew J. Kraeutler; John W. Belk; Rachel M. Frank; Eric C. McCarty; Jonathan T. Bravman

Background: Focal chondral defects (FCDs) of the knee are believed to contribute to the development of osteoarthritis (OA), resulting in pain and dysfunction. Purpose: To investigate whether untreated FCDs of the knee progress to radiographically evident OA over time. Study Design: Systematic review; Level of evidence, 3. Methods: A literature review was performed by searching the PubMed, Embase, and Cochrane Library databases to locate studies evaluating clinical and/or radiological outcomes of patients with FCDs that were diagnosed by arthroscopic surgery or magnetic resonance imaging (MRI) and were left untreated with a minimum 2-year follow-up. Additionally, studies were included if there was a radiographic assessment of OA. Search terms used were “knee,” “focal,” “isolated,” “chondral,” “cartilage,” and “osteoarthritis.” Studies were evaluated based on clinical/radiological outcomes and OA risk factors. The study methodology was assessed using the modified Coleman Methodology Score. Results: Eight studies comprising 1425 knees met the inclusion criteria. All studies were of level 3 evidence. The risk of incident cartilage damage (enlargement of original FCDs or incidence of additional FCDs) at latest follow-up was assessed in 3 studies, while 1 study only reported the incidence of cartilage damage at follow-up. All 4 studies noted an increased progression of cartilage damage at follow-up. The progression of cartilage damage was most commonly seen in the patellofemoral joint and medial femoral condyle but was not associated with the development of knee OA based on the Kellgren-Lawrence grade. MRI of the FCDs revealed increased water content, cartilage deterioration, and proteoglycan loss within the medial and lateral compartments. Conclusion: Patients with untreated FCDs of the knee joint are more likely to experience a progression of cartilage damage, although the studies included in this review did not demonstrate the development of radiographically evident OA within 2 years of follow-up.


American Journal of Sports Medicine | 2018

Descriptive Epidemiology of the MOON Shoulder Instability Cohort

Matthew J. Kraeutler; Eric C. McCarty; John W. Belk; Brian R. Wolf; Carolyn M. Hettrich; Shannon Ortiz; Jonathan T. Bravman; Keith M. Baumgarten; Julie Y. Bishop; Matthew J. Bollier; Robert H. Brophy; James L. Carey; James E. Carpenter; Charles L. Cox; Brian T. Feeley; John A. Grant; Grant L. Jones; John Kuhn; John D. Kelly; C. Benjamin Ma; Robert G. Marx; Bruce S. Miller; Brian J. Sennett; Matthew V. Smith; Rick W. Wright; Alan L. Zhang

Background: Shoulder instability is a common diagnosis among patients undergoing shoulder surgery. Purpose: To perform a descriptive analysis of patients undergoing surgery for shoulder instability through a large multicenter consortium. Study Design: Case series; Level of evidence, 4. Methods: All patients undergoing surgery for shoulder instability who were enrolled in the MOON Shoulder Instability Study were included. Baseline demographics included age, sex, body mass index, and race. Baseline patient-reported outcomes (PROs) included the American Shoulder and Elbow Surgeons (ASES) score, Shoulder Activity Score, Western Ontario Shoulder Instability Index (WOSI), 36-Item Health Survey (RAND-36), and Single Assessment Numeric Evaluation (SANE). The preoperative physician examination included active range of motion (ROM) and strength testing. Preoperative imaging assessments with plain radiography, magnetic resonance imaging (MRI), and computed tomography were also included and analyzed. Results: Twenty-six surgeons had enrolled 863 patients (709 male, 154 female) across 10 clinical sites. The mean age for the cohort was 24 years (range, 12-63 years). Male patients represented 82% of the cohort. The primary direction of instability was anterior for both male (74%) and female (73%) patients. Football (24%) and basketball (13%) were the most common sports in which the primary shoulder injury occurred. No clinically significant differences were found in preoperative ROM between the affected and unaffected sides for any measurement taken. Preoperative MRI scans were obtained in 798 patients (92%). An anterior labral tear was the most common injury found on preoperative MRI, seen in 66% of patients, followed by a Hill-Sachs lesion in 41%. Poor PRO scores were recorded preoperatively (mean: ASES, 72.4; WOSI, 43.3; SANE, 46.6). Conclusion: The MOON Shoulder Instability Study has enrolled the largest cohort of patients undergoing shoulder stabilization to date. Anterior instability is most common among shoulder instability patients, and most patients undergoing shoulder stabilization are in their early 20s or younger. The results of this study provide important epidemiological information for patients undergoing shoulder stabilization surgery.


Shoulder & Elbow | 2017

Evaluation of information available on the internet regarding reverse total shoulder arthroplasty

Darby A. Houck; Matthew J. Kraeutler; John W. Belk; Eric C. McCarty; Jonathan T. Bravman

Background Prior studies have analyzed the quality of information available on the Internet regarding common orthopaedic surgical procedures. The purpose of the present study was to evaluate the quality of information available for reverse total shoulder arthroplasty (rTSA). Methods Websites were identified using the search term ‘reverse total shoulder arthroplasty’ and the first 50 websites from three separate search engines (Google, Yahoo, and Bing) were selected for evaluation of authorship and quality of information using the DISCERN instrument (www.discern.org.uk). After disregarding duplicated or overlapping websites within and among search engines, 90 of the total 150 websites were evaluated. A one-way analysis of variance test was used to compare differences in DISCERN scores between three categories of authorship (academic, private, other). Results The majority of the websites evaluated were authored by academic (43%) and private institutions (36%). These were the most credible sources, providing overall better quality and reliability than other sources. DISCERN reliable (p = 0.017) and overall scores (p = 0.020) were significantly higher for academic institutions compared to other websites. Conclusions The information available on the Internet pertaining to reverse total shoulder arthroplasty is highly variable and provides moderate quality information about treatment choices with some limitations based on the DISCERN instrument.

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Eric C. McCarty

University of Colorado Denver

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Matthew J. Kraeutler

University of Colorado Denver

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Jonathan T. Bravman

University of Colorado Denver

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Darby A. Houck

University of Colorado Denver

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Trevor J. Carver

University of Colorado Denver

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Hayden A. Marshall

University of Colorado Denver

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Justin M. Purcell

University of Colorado Denver

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Alan L. Zhang

University of California

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Brian J. Sennett

University of Colorado Denver

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Brian R. Wolf

Vanderbilt University Medical Center

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