Charles J. Gatt

Effect of Graft Choice on the Outcome of Revision Anterior Cruciate Ligament Reconstruction in the Multicenter ACL Revision Study (MARS) Cohort

Background: Most surgeons believe that graft choice for anterior cruciate ligament (ACL) reconstruction is an important factor related to outcome; however, graft choice for revision may be limited due to previously used grafts. Hypotheses: Autograft use would result in increased sports function, increased activity level, and decreased osteoarthritis symptoms (as measured by validated patient-reported outcome instruments). Autograft use would result in decreased graft failure and reoperation rate 2 years after revision ACL reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: Patients undergoing revision ACL reconstruction were identified and prospectively enrolled by 83 surgeons at 52 sites. Data collected included baseline demographics, surgical technique, pathologic abnormalities, and the results of a series of validated, patient-reported outcome instruments (International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Marx activity rating score). Patients were followed up at 2 years and asked to complete the identical set of outcome instruments. Incidences of additional surgery and reoperation due to graft failure were also recorded. Multivariate regression models were used to determine the predictors (risk factors) of IKDC, KOOS, WOMAC, Marx scores, graft rerupture, and reoperation rate at 2 years after revision surgery. Results: A total of 1205 patients (697 [58%] males) were enrolled. The median age was 26 years. In 88% of patients, this was their first revision, and 341 patients (28%) were undergoing revision by the surgeon who had performed the previous reconstruction. The median time since last ACL reconstruction was 3.4 years. Revision using an autograft was performed in 583 patients (48%), allograft was used in 590 (49%), and both types were used in 32 (3%). Questionnaire follow-up was obtained for 989 subjects (82%), while telephone follow-up was obtained for 1112 (92%). The IKDC, KOOS, and WOMAC scores (with the exception of the WOMAC stiffness subscale) all significantly improved at 2-year follow-up (P < .001). In contrast, the 2-year Marx activity score demonstrated a significant decrease from the initial score at enrollment (P < .001). Graft choice proved to be a significant predictor of 2-year IKDC scores (P = .017). Specifically, the use of an autograft for revision reconstruction predicted improved score on the IKDC (P = .045; odds ratio [OR] = 1.31; 95% CI, 1.01-1.70). The use of an autograft predicted an improved score on the KOOS sports and recreation subscale (P = .037; OR = 1.33; 95% CI, 1.02-1.73). Use of an autograft also predicted improved scores on the KOOS quality of life subscale (P = .031; OR = 1.33; 95% CI, 1.03-1.73). For the KOOS symptoms and KOOS activities of daily living subscales, graft choice did not predict outcome score. Graft choice was a significant predictor of 2-year Marx activity level scores (P = .012). Graft rerupture was reported in 37 of 1112 patients (3.3%) by their 2-year follow-up: 24 allografts, 12 autografts, and 1 allograft and autograft. Use of an autograft for revision resulted in patients being 2.78 times less likely to sustain a subsequent graft rupture compared with allograft (P = .047; 95% CI, 1.01-7.69). Conclusion: Improved sports function and patient-reported outcome measures are obtained when an autograft is used. Additionally, use of an autograft shows a decreased risk in graft rerupture at 2-year follow-up. No differences were noted in rerupture or patient-reported outcomes between soft tissue and bone–patellar tendon–bone grafts. Surgeon education regarding the findings of this study has the potential to improve the results of revision ACL reconstruction.

Impact Loading of the Lumbar Spine During Football Blocking

The purpose of our study was to determine the impact force to the lumbar spine when football players hit a blocking sled. We quantified the loads at the L4-5 motion segment throughout the blocking sequence. Five Division I-A college football linemen were subjects for our study. Kinematic data were obtained while the subjects hit a blocking sled instrumented with a force plate. Three plane forces were then calculated from these data. The average impact force measured at the blocking sled was 3013 ± 598 N. The average peak compression force at the L4-5 motion segment was 8679 ± 1965 N. The average peak anteroposterior shear force was 3304 ± 1116 N, and the average peak lateral shear force was 1709 ± 411 N. The magnitude of the loads on the L4-5 motion segment during foot ball blocking exceed those determined during fatigue studies to cause pathologic changes in both the lumbar disk and the pars interarticularis. These data suggest that the mechanics of repetitive blocking may be re sponsible for the increased incidence of lumbar spine injury incurred by football linemen.

Design and mechanical evaluation of a novel fiber-reinforced scaffold for meniscus replacement†

A fiber-reinforced degradable scaffold for replacement of meniscal tissue was designed, fabricated, and mechanically evaluated. The hypotheses were that (1) the fiber network design would share a portion of compressive loads via the generation of circumferential tensile loads, and (2) the scaffold tensile properties would be similar to those of the meniscus. Two meniscus scaffold designs varying in fiber content (1000 or 500 fibers: MS1000, MS500) underwent cyclic compressive loading up to 100 and 250N, with resultant tensile loads measured at the anterior and posterior anchors. Standard tensile testing was also performed on each device and ovine menisci. Both scaffolds generated tensile loads directly proportional to the applied compressive loads, with MS1000 scaffolds generating approximately twice the tensile loads of MS500 scaffolds. The tensile strength of MS1000 scaffolds was significantly higher than that of the medial and lateral ovine menisci, and approximately twice that of the MS500 scaffolds. The stiffness of MS1000 scaffolds was lower than that of the lateral meniscus, but not statistically different from that of the medial meniscus. These results support our hypotheses that this novel fiber-reinforced scaffold can mimic the tensile and hoop stress behavior of normal meniscal tissue under compressive loading. The circumferential tensile strength and stiffness are appropriate for a meniscus replacement device.

Osteoarthritis classification scales: Interobserver reliability and arthroscopic correlation

BACKGROUND Osteoarthritis of the knee is commonly diagnosed and monitored with radiography. However, the reliability of radiographic classification systems for osteoarthritis and the correlation of these classifications with the actual degree of confirmed degeneration of the articular cartilage of the tibiofemoral joint have not been adequately studied. METHODS As the Multicenter ACL (anterior cruciate ligament) Revision Study (MARS) Group, we conducted a multicenter, prospective longitudinal cohort study of patients undergoing revision surgery after anterior cruciate ligament reconstruction. We followed 632 patients who underwent radiographic evaluation of the knee (an anteroposterior weight-bearing radiograph, a posteroanterior weight-bearing radiograph made with the knee in 45° of flexion [Rosenberg radiograph], or both) and arthroscopic evaluation of the articular surfaces. Three blinded examiners independently graded radiographic findings according to six commonly used systems-the Kellgren-Lawrence, International Knee Documentation Committee, Fairbank, Brandt et al., Ahlbäck, and Jäger-Wirth classifications. Interobserver reliability was assessed with use of the intraclass correlation coefficient. The association between radiographic classification and arthroscopic findings of tibiofemoral chondral disease was assessed with use of the Spearman correlation coefficient. RESULTS Overall, 45° posteroanterior flexion weight-bearing radiographs had higher interobserver reliability (intraclass correlation coefficient = 0.63; 95% confidence interval, 0.61 to 0.65) compared with anteroposterior radiographs (intraclass correlation coefficient = 0.55; 95% confidence interval, 0.53 to 0.56). Similarly, the 45° posteroanterior flexion weight-bearing radiographs had higher correlation with arthroscopic findings of chondral disease (Spearman rho = 0.36; 95% confidence interval, 0.32 to 0.39) compared with anteroposterior radiographs (Spearman rho = 0.29; 95% confidence interval, 0.26 to 0.32). With respect to standards for the magnitude of the reliability coefficient and correlation coefficient (Spearman rho), the International Knee Documentation Committee classification demonstrated the best combination of good interobserver reliability and medium correlation with arthroscopic findings. CONCLUSIONS The overall estimates with the six radiographic classification systems demonstrated moderate (anteroposterior radiographs) to good (45° posteroanterior flexion weight-bearing radiographs) interobserver reliability and medium correlation with arthroscopic findings. The International Knee Documentation Committee classification assessed with use of 45° posteroanterior flexion weight-bearing radiographs had the most favorable combination of reliability and correlation. LEVEL OF EVIDENCE Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Surgical Treatment of Symptomatic Superior Labrum Anterior-Posterior Tears in Patients Older Than 40 Years A Systematic Review

Background: Successful arthroscopic repair of symptomatic superior labral tears in young athletes has been well documented. Superior labral repair in patients older than 40 years is controversial, with concerns for residual postoperative pain, stiffness, and higher rates of revision surgery. Purpose: To analyze the published data on the surgical treatment of superior labral injuries in patients aged ≥40 years, including those with concomitant injuries to the rotator cuff. Study Design: Systematic review. Methods: A systematic review of the literature was performed using the Preferred Reporting Items of Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The MEDLINE database via PubMed and the Cochrane Database of Systematic Reviews were searched for articles related to superior labrum anterior-posterior (SLAP) tears. Studies were included if they met the following criteria: the study contained at least 1 group of patients who had undergone arthroscopic repair of a type II or IV SLAP lesion with a minimum 2-year follow-up, objective and/or functional scoring systems were used to evaluate postoperative outcomes, and the mean patient age was ≥40 years for at least 1 treatment arm or subgroup analysis. Studies were excluded if the article was a review or if the article included data for SLAP type I, III, or V to X tears or Bankart lesions. Results: While several authors reported equivalent outcomes of SLAP repair in patients both older than 40 years and younger than 40 years, others demonstrated significantly higher failure rates in the older cohort. Decreased patient satisfaction and increasing complications, including postoperative stiffness and reoperations, occur at higher rates as the patient age increases. The literature demonstrates that biceps tenotomy and tenodesis are reliable alternatives to SLAP repair and that biceps tenotomy is a viable revision procedure for failed SLAP repair. With concomitant rotator cuff tears, the evidence favors debridement or biceps tenotomy over SLAP repair. Conclusion: While studies show that good outcomes can be obtained with SLAP repair in an older cohort of patients, age older than 40 years and workers’ compensation status are independent risk factors for increased surgical complications. The cumulative evidence supports labral debridement or biceps tenotomy over labral repair when an associated rotator cuff injury is present.

Application of the dual-frequency ultrasonometer for osteoporosis detection

The paper presents results of a clinical validation study of Bone UltraSonic Scanner (BUSS), a novel dual-frequency axial transmission ultrasonometer, developed by Artann Laboratories. Assessment of bone conditions is based on evaluating relative changes of the axial profiles of ultrasonic characteristics in long bones and utilizes bulk and guided acoustic waves. The objective of this study was to determine the ability of BUSS to discriminate osteoporosis development stages. A total of 93 menopausal and post-menopausal women divided into five groups from normal to advanced osteoporosis according to their DXA hip t-score were enrolled in the study. The 2D waveform profiles at low (0.1 MHz) and high (1 MHz) frequencies were obtained by scanning 15 cm along the proximal tibia. A multi-parametric linear classifier based on a set of the parameters derived from 2D acoustic waveform profiles has been developed. The efficiency of this classifier in differentiating osteoporosis from a normal sample was assessed using a receiver operating characteristic (ROC) curve analysis. Based on the ROC analysis, BUSS demonstrated 76% sensitivity and 70% specificity to DXA-identified osteoporosis. The area under the ROC curve, which is a measure of how well a parameter can distinguish between the two diagnostic groups (diseased/normal) was 79.3%. The study confirmed BUSSs capability to discriminate between stages of bone atrophy and in particular to distinguish early changes induced by osteoporosis.

Successful Total Meniscus Reconstruction Using a Novel Fiber-Reinforced Scaffold: A 16- and 32-Week Study in an Ovine Model.

Background: Meniscus injuries in the United States result in an estimated 850,000 surgical procedures each year. Although meniscectomies are the most commonly performed orthopaedic surgery, little advancement has been made in meniscus replacement and regeneration, and there is currently no total meniscus replacement device approved by the Food and Drug Administration. Hypothesis: A novel fiber-reinforced meniscus scaffold can be used as a functional total meniscus replacement. Study Design: Controlled laboratory study. Methods: A tyrosine-derived, polymer fiber–reinforced collagen sponge meniscus scaffold was evaluated mechanically (tensile and compressive testing) and histologically after 16 and 32 weeks of implantation in an ovine total meniscectomy model (N = 20; 16 implants plus 4 meniscectomies, divided equally over the 2 time periods). The extent of cartilage damage was also measured on tibial plateaus by use of toluidine blue surface staining and on femoral condyles by use of Mankin scores on histological slides. Results: Scaffolds induced formation of neomeniscus tissue that remained intact and functional, with breaking loads approximating 250 N at both 16 and 32 weeks compared with 552 N for native menisci. Tensile stiffness values (99 and 74 N/mm at 16 and 32 weeks, respectively) were also comparable with those of the native meniscus (147 N/mm). The compressive modulus of the neomeniscus tissue (0.33 MPa at both 16 and 32 weeks) was significantly increased compared with unimplanted (time 0) scaffolds (0.15 MPa). There was histological evidence of extensive tissue ingrowth and extracellular matrix deposition, with immunohistochemical evidence of types I and II collagen. Based on significantly decreased surface damage scores as well as Mankin scores, the scaffold implants provided greater protection of articular cartilage compared with the untreated total meniscectomy. Conclusion: This novel fiber-reinforced meniscus scaffold can act as a functional meniscus replacement, with mechanical properties similar to those of the native meniscus, while protecting the articular cartilage of the knee from the extensive damage after a total meniscectomy. Clinical Relevance: This meniscus replacement scaffold has the potential to improve surgical treatment and provide better long-term outcomes for those suffering from severe meniscus damage.

Meniscal and Articular Cartilage Predictors of Clinical Outcome After Revision Anterior Cruciate Ligament Reconstruction

Background: Revision anterior cruciate ligament (ACL) reconstruction has been documented to have worse outcomes compared with primary ACL reconstructions. Purpose/Hypothesis: The purpose of this study was to determine if the prevalence, location, and/or degree of meniscal and chondral damage noted at the time of revision ACL reconstruction predicts activity level, sports function, and osteoarthritis symptoms at 2-year follow-up. The hypothesis was that meniscal loss and high-grade chondral damage noted at the time of revision ACL reconstruction will result in lower activity levels, decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery. Study Design: Cohort study; Level of evidence, 2. Methods: Between 2006 and 2011, a total of 1205 patients who underwent revision ACL reconstruction by 83 surgeons at 52 hospitals were accumulated for study of the relationship of meniscal and articular cartilage damage to outcome. Baseline demographic and intraoperative data, including the International Knee Documentation Committee (IKDC) subjective knee evaluation, Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Marx activity score, were collected initially and at 2-year follow-up to test the hypothesis. Regression analysis was used to control for age, sex, body mass index, smoking status, activity level, baseline outcome scores, revision number, time since last ACL reconstruction, incidence of having a previous ACL reconstruction on the contralateral knee, previous and current meniscal and articular cartilage injury, graft choice, and surgeon years of experience to assess the meniscal and articular cartilage risk factors for clinical outcomes 2 years after revision ACL reconstruction. Results: At 2-year follow-up, 82% (989/1205) of the patients returned their questionnaires. It was found that previous meniscal injury and current articular cartilage damage were associated with the poorest outcomes, with prior lateral meniscectomy and current grade 3 to 4 trochlear articular cartilage changes having the worst outcome scores. Activity levels at 2 years were not affected by meniscal or articular cartilage pathologic changes. Conclusion: Prior lateral meniscectomy and current grade 3 to 4 changes of the trochlea were associated with worse outcomes in terms of decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery, but they had no effect on activity levels. Registration: NCT00625885

One-Year Outcomes of Total Meniscus Reconstruction Using a Novel Fiber-Reinforced Scaffold in an Ovine Model

Background: Meniscus injuries and resulting meniscectomies lead to joint deterioration, causing pain, discomfort, and instability. Tissue-engineered devices to replace the meniscus have not shown consistent success with regard to function, mechanical integrity, or protection of cartilage. Purpose: To evaluate a novel resorbable polymer fiber–reinforced meniscus reconstruction scaffold in an ovine model for 52 weeks and assess its integrity, tensile and compressive mechanics, cell phenotypes, matrix organization and content, and protection of the articular cartilage surfaces. Study Design: Controlled laboratory study. Methods: Eight skeletally mature ewes were implanted with the fiber-reinforced scaffold after total meniscectomy, and 2 additional animals had untreated total meniscectomies. Animals were sacrificed at 52 weeks, and the explants and articular surfaces were analyzed macroscopically. Explants were characterized by ultimate tensile testing, confined compression creep testing, and biochemical, histological, and immunohistochemical analyses. Cartilage damage was characterized using the Mankin score on histologic slides from both the femur and tibia. Results: One sheep was removed from the study because of a torn extensor tendon; the remaining 7 explants remained fully intact and incorporated into the bone tunnels. All explants exhibited functional tensile loads, tensile stiffnesses, and compressive moduli. Fibrocartilagenous repair with both types 1 and 2 collagen were observed, with areas of matrix organization and biochemical content similar to native tissue. Narrowing in the body region was observed in 5 of 7 explants. Mankin scores showed less cartilage damage in the explant group (femoral condyle: 3.43 ± 0.79, tibial plateau: 3.50 ± 1.63) than in the meniscectomy group (femoral condyle: 8.50 ± 3.54, tibial plateau: 6.75 ± 2.47) and were comparable with Mankin scores at the previously reported 16- and 32-week time points. Conclusion: A resorbable fiber-reinforced meniscus scaffold supports formation of functional neomeniscus tissue, with the potential to prevent joint degeneration that typically occurs after total meniscectomy. Further studies with improvements to the initial mechanics of the scaffold and testing for longer time periods are warranted. Clinical Relevance: Meniscectomy is an extremely common orthopaedic procedure, and few options currently exist for the treatment of significant loss of meniscus tissue. Successful development of a tissue-engineered meniscus scaffold could substantially reduce the incidence of postmeniscectomy joint degeneration and the subsequent procedures used for its treatment.

A comparison of degradable synthetic polymer fibers for anterior cruciate ligament reconstruction

We compared mechanical properties, degradation rates, and cellular compatibilities of two synthetic polymer fibers potentially useful as ACL reconstruction scaffolds: poly(desaminotyrosyl-tyrosine dodecyl dodecanedioate)(12,10), p(DTD DD) and poly(L-lactic acid), PLLA. The yield stress of ethylene oxide (ETO) sterilized wet fibers was 150 +/- 22 MPa and 87 +/- 12 MPa for p(DTD DD) and PLLA, respectively, with moduli of 1.7 +/- 0.1 MPa and 4.4 +/- 0.43 MPa. Strength and molecular weight retention were determined after incubation under physiological conditions at varying times. After 64 weeks strength decreased to 20 and 37% of the initial sterile fiber values and MW decreased to 41% and 36% of the initial values for p(DTD DD) and PLLA, respectively. ETO sterilization had no significant effect on mechanical properties. Differences in mechanical behavior may be due to the semicrystalline nature of PLLA and the small degree of crystallinity induced by mesogenic ordering in p(DTD DD) suggested by DSC analysis. Fibroblast growth was similar on 50-fiber scaffolds of both polymers through 16 days in vitro. These data suggest that p(DTD DD) fibers, with higher strength, lower stiffness, favorable degradation rate and cellular compatibility, may be a superior alternative to PLLA fibers for development of ACL reconstruction scaffolds.