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Allograft safety is a great concern owing to the risk of disease transmission from nonsterile tissues. Radiation sterilization is not used routinely because of deleterious effects on the mechanical integrity and stability of allograft collagen. We previously reported several individual cross-linking or free radical scavenging treatments provided some radioprotective effects for tendons. We therefore asked whether a combination of treatments would provide an improved protective effect after radiation exposure regarding mechanical properties and enzyme resistance. To address this question we treated 90 rabbit Achilles tendons with a combination of cross-linking (1-ethyl-3-[3-dimethyl aminopropyl] carbodiimide [EDC]) and one of three scavenging regimens (mannitol, ascorbate, or riboflavin). Tendons then were exposed to one of three radiation conditions (gamma or electron beam irradiation at 50 kGy or unsterilized). Combination-treated tendons (10 per group) had increases in mechanical properties and higher resistance to collagenase digestion compared with EDC-only and untreated tendons. Irradiated tendons treated with EDC-mannitol, -ascorbate, and -riboflavin combinations had comparable strength to native tendon and had averages of 26%, 39%, and 37% greater, respectively, than those treated with EDC-only. Optimization of a cross-linking protocol and free radical scavenging cocktail is ongoing with the goal of ensuring sterile allografts through irradiation while maintaining their structure and mechanical properties. [ABSTRACT FROM AUTHOR]

Ionizing radiation could supplement tissue bank screening to further reduce the probability of diseases transmitted by allografts if denaturation effects can be minimized. It is important, however, such sterilization procedures be nondetrimental to tissues. We compared crosslinking and free radical scavenging potential methods to accomplish this task in tendon tissue. In addition, two forms of ionizing irradiation, gamma and electron beam (e-beam), were also compared. Crosslinkers included 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and glucose, which were used to add exogenous crosslinks to collagen. Free radical scavengers included mannitol, ascorbate, and riboflavin. Radioprotective effects were assessed through tensile testing and collagenase resistance testing after irradiation at 25 kGy and 50 kGy. Gamma and e-beam irradiation produced similar degenerative effects. Crosslinkers had the highest strength at 50 kGy, EDC treated tendons had 54% and 49% higher strength than untreated, for gamma and e-beam irradiation respectively. Free radical scavengers showed protective effects up to 25 kGy, especially for ascorbate and riboflavin. Crosslinked samples had higher resistance to collagenase and over a wider dose range than scavenger-treated. Of the options studied, the data suggest EDC precrosslinking or glucose treatment provides the best maintenance of native tendon properties after exposure to ionizing irradiation. [ABSTRACT FROM AUTHOR]

As more outpatient orthopaedic surgical procedures are performed, postoperative pain control has gained importance. The benefits of preemptive analgesia, the use of analgesics or anesthetics or both before painful stimuli to prevent or reduce pain, have been widely published in the anesthesia and general surgery literature, but not in orthopaedic literature. We prospectively compared the effects, on postoperative pain and narcotic use, of intraarticular preoperative injections of 1) placebo with epinephrine, 2) bupivacaine with epinephrine, and 3) bupivacaine and morphine with epinephrine. Thirty patients (10 in each group) underwent arthroscopic anterior cruciate ligament reconstruction using patellar tendon autograft under general anesthesia. Pain was assessed with a 10-point visual analog scale pre- and postoperatively, and postoperative narcotic pain medication use was recorded. Postoperative pain was significantly greater in group 1 (placebo) than in the preemptive-treatment groups (groups 2 and 3), and in group 2 than in group 3. The differences became less apparent with time, and after 1 hour, no significant differences in pain scores existed between the groups. However, intravenous narcotic pain medication was administered in the recovery room to patients with pain scores greater than 5, equalizing pain scores. Group 3 used significantly less postoperative narcotic medication than group 1. Preemptive analgesia using intraarticular bupivacaine and morphine with epinephrine resulted in lower pain scores during the 1st hour after an arthroscopic anterior cruciate ligament reconstruction than did preemptive treatment with bupivacaine and epinephrine or placebo and epinephrine. [ABSTRACT FROM AUTHOR]

Background: High ankle sprains are common athletic injuries and can be associated with long-term sequelae. Regardless of operative or nonoperative treatment, there is a paucity of data in the literature about the long-term outcomes of high ankle sprains., Hypothesis: Nonoperative treatment of high ankle sprains utilizing a standardized protocol will result in good long-term outcomes., Study Design: Case series; Level of evidence, 4., Methods: Patients who experienced a high ankle sprain without radiographic diastasis of the syndesmosis were identified from a previous study database and contacted for long-term follow-up. All patients were high school or National Collegiate Athletic Association Division IA athletes at initial injury and were treated nonoperatively with the same standardized protocol. Patients completed a questionnaire that included documentation of any interim ankle injuries, 2 different patient-reported outcome scores, and ankle radiographs to conduct Kellgren-Lawrence scoring for ankle osteoarthritis., Results: In total, 76 cases in 74 patients were identified in the database. A total of 40 patients were successfully contacted, and 31 patients (24 collegiate and 7 high school athletes) with 33 high ankle sprains completed the survey (31/40; 77.5%). The mean age at follow-up was 45 years (range, 34-50 years), with a mean time from injury to follow-up of 25 years. Overall, 93.5% (n = 29) of the respondents were male, and 42% (n = 13) of the respondents reported an ipsilateral ankle injury since their initial injury, with 16% (n = 5) having ankle or Achilles surgery. The mean Patient-Reported Outcomes Measurement Information System-10 score was 53.4 (SD, 8.3; range, 37.4-67.7), PROMIS median (IQR), 54.1 (39.9, 68.3), and the mean Self-reported Foot and Ankle Score score was 42.7 (SD, 5.86). Follow-up ankle radiographs were obtained in 11 (35%) of the respondents; 27% had Kellgren-Lawrence grade >2 osteoarthritis, and 36% had signs of heterotopic ossification on imaging. The mean tibiofibular clear space was 4.5 mm, and the mean tibiofibular overlap was 7.15 mm, with 27% of patients demonstrating some tibiotalar narrowing., Conclusion: At long-term follow-up, nonoperative management of high ankle sprains without diastasis on imaging was associated with acceptable patient-reported functional outcomes and low rates of subsequent ankle injuries. There was a high incidence of arthritis, but most cases were not clinically significant. This case series shows the natural history of nonoperatively treated high ankle sprains and may serve as a comparison for different management techniques in the future., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This project was partially funded by a grant from the Athletic Trainers’ Society of New Jersey. P.S.B. has received hospitality payments from Smith & Nephew. C.J.G. has received support for education from SeaPearl. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Background: It is difficult to diagnose and grade bony stress injury (BSI) in the athletic adolescent population without advanced imaging. Radiographs are recommended as a first imaging modality, but have limited sensitivity and, even when findings are present, advanced imaging is often recommended., Hypothesis: It was hypothesized that the significance of radiographs is underestimated for BSI in the adolescent with positive clinical examination and history findings., Study Design: Case series., Level of Evidence: Level 4., Methods: A total of 80 adolescent athletes with a history of shin pain underwent clinical examination by an orthopaedic surgeon. On the day of clinical examination, full-length bilateral tibial radiographs and magnetic resonance imaging (MRI) scans were obtained. MRI scans were reviewed using Fredericson grading for BSI. At the completion of the study, radiographic images were re-evaluated by 2 musculoskeletal (MSK) radiologists, blinded to MRI and clinical examination results, who reviewed the radiographs for evidence of BSI. Radiographic results were compared with clinical examination and MRI findings. Sensitivity, specificity, negative predictive value, and positive predictive value were calculated based on comparison with MRI., Results: All radiographs were originally read as normal. Of the tibia studied, 80% (127 of 160) showed evidence of BSI on MRI. None of the original radiographs demonstrated a fracture line on initial review by the orthopaedic surgeons. Retrospective review by 2 MSK radiologists identified 27% of radiographs (34 of 127) with evidence of abnormality, which correlated with clinical examination and significant findings on MRI. Review of radiographs found evidence of new bone on 0 of 28 Fredericson grade 0, 0 of 19 Fredericson grade I, 11 of 80 (13.7%) Fredericson grade II, 18 of 28 (64%) Fredericson grade III, and 5 of 5 (100%) Fredericson grade IV. Sensitivity of radiographs showed evidence of new bone on 27% (34 of 127) of initial radiographs, with presence more common with greater degree of BSI, as 23 of 33 (70%) were higher-grade injuries (III of IV) of BSI. Specificity and positive predictive value were 100%, while negative predictive value was 17%., Conclusion: These findings highlight the importance of initial radiographs in identifying high-grade BSI. As radiographs are readily available in most office settings of sports medicine physicians, this information can influence the management of adolescent athletic BSI without the need to delay treatment to obtain an MRI., Clinical Relevance: Adolescent athletes with radiographic evidence of BSI should be treated in a timely and more conservative manner, given the likelihood of higher-grade BSI. In addition, clinicians knowledgeable of the radiographic findings of high-grade BSI should feel more confident that a negative initial radiograph is not likely to be a high-grade BSI and can modify their treatment plans accordingly.

Background: Meniscal and chondral damage is common in the patient undergoing revision anterior cruciate ligament (ACL) reconstruction., Purpose: To determine if meniscal and/or articular cartilage pathology at the time of revision ACL surgery significantly influences a patient's outcome at 6-year follow-up., Study Design: Cohort study; Level of evidence, 3., Methods: Patients undergoing revision ACL reconstruction were prospectively enrolled between 2006 and 2011. Data collection included baseline demographics, surgical technique, pathology, treatment, and scores from 4 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 Scale. Patients were followed up at 6 years and asked to complete the identical set of outcome instruments. Regression analysis assessed the meniscal and articular cartilage pathology risk factors for clinical outcomes 6 years after revision ACL reconstruction., Results: An overall 1234 patients were enrolled (716 males, 58%; median age, 26 years). Surgeons reported the pathology at the time of revision surgery in the medial meniscus (45%), lateral meniscus (36%), medial femoral condyle (43%), lateral femoral condyle (29%), medial tibial plateau (11%), lateral tibial plateau (17%), patella (30%), and trochlea (21%). Six-year follow-up was obtained on 79% of the sample (980/1234). Meniscal pathology and articular cartilage pathology (medial femoral condyle, lateral femoral condyle, lateral tibial plateau, trochlea, and patella) were significant drivers of poorer patient-reported outcomes at 6 years (IKDC, KOOS, WOMAC, and Marx). The most consistent factors driving outcomes were having a medial meniscal excision (either before or at the time of revision surgery) and patellofemoral articular cartilage pathology. Six-year Marx activity levels were negatively affected by having either a repair/excision of the medial meniscus (odds ratio range, 1.45-1.72; P ≤ .04) or grade 3-4 patellar chondrosis (odds ratio, 1.72; P = .04). Meniscal pathology occurring before the index revision surgery negatively affected scores on all KOOS subscales except for sports/recreation ( P < .05). Articular cartilage pathology significantly impaired all KOOS subscale scores ( P < .05). Lower baseline outcome scores, higher body mass index, being a smoker, and incurring subsequent surgery all significantly increased the odds of reporting poorer clinical outcomes at 6 years., Conclusion: Meniscal and chondral pathology at the time of revision ACL reconstruction has continued significant detrimental effects on patient-reported outcomes at 6 years after revision surgery.

Background: Lytic or malpositioned tunnels may require bone grafting during revision anterior cruciate ligament reconstruction (rACLR) surgery. Patient characteristics and effects of grafting on outcomes after rACLR are not well described., Purpose: To describe preoperative characteristics, intraoperative findings, and 2-year outcomes for patients with rACLR undergoing bone grafting procedures compared with patients with rACLR without grafting., Study Design: Cohort study; Level of evidence, 3., Methods: A total of 1234 patients who underwent rACLR were prospectively enrolled between 2006 and 2011. Baseline revision and 2-year characteristics, surgical technique, pathology, treatment, and patient-reported outcome instruments (International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMaster Universities Osteoarthritis Index, and Marx Activity Rating Scale [Marx]) were collected, as well as subsequent surgery information, if applicable. The chi-square and analysis of variance tests were used to compare group characteristics., Results: A total of 159 patients (13%) underwent tunnel grafting-64 (5%) patients underwent 1-stage and 95 (8%) underwent 2-stage grafting. Grafting was isolated to the femur in 31 (2.5%) patients, the tibia in 40 (3%) patients, and combined in 88 patients (7%). Baseline KOOS Quality of Life (QoL) and Marx activity scores were significantly lower in the 2-stage group compared with the no bone grafting group ( P ≤ .001). Patients who required 2-stage grafting had more previous ACLRs ( P < .001) and were less likely to have received a bone-patellar tendon-bone or a soft tissue autograft at primary ACLR procedure ( P ≤ .021) compared with the no bone grafting group. For current rACLR, patients undergoing either 1-stage or 2-stage bone grafting were more likely to receive a bone-patellar tendon-bone allograft ( P ≤ .008) and less likely to receive a soft tissue autograft ( P ≤ .003) compared with the no bone grafting group. At 2-year follow-up of 1052 (85%) patients, we found inferior outcomes in the 2-stage bone grafting group (IKDC score = 68; KOOS QoL score = 44; KOOS Sport/Recreation score = 65; and Marx activity score = 3) compared with the no bone grafting group (IKDC score = 77; KOOS QoL score = 63; KOOS Sport/Recreation score = 75; and Marx activity score = 7) ( P ≤ .01). The 1-stage bone graft group did not significantly differ compared with the no bone grafting group., Conclusion: Tunnel bone grafting was performed in 13% of our rACLR cohort, with 8% undergoing 2-stage surgery. Patients treated with 2-stage grafting had inferior baseline and 2-year patient-reported outcomes and activity levels compared with patients not undergoing bone grafting. Patients treated with 1-stage grafting had similar baseline and 2-year patient-reported outcomes and activity levels compared with patients not undergoing bone grafting.

Background: Patients with anterior cruciate ligament (ACL) revision report lower outcome scores on validated knee questionnaires postoperatively compared to cohorts with primary ACL reconstruction. In a previously active population, it is unclear if patient-reported outcomes (PROs) are associated with a return to activity (RTA) or vary by sports participation level (higher level vs. recreational athletes)., Hypotheses: Individual RTA would be associated with improved outcomes (ie, decreased knee symptoms, pain, function) as measured using validated PROs. Recreational participants would report lower PROs compared with higher level athletes and be less likely to RTA., Study Design: Cohort study; Level of evidence, 2., Methods: There were 862 patients who underwent a revision ACL reconstruction (rACLR) and self-reported physical activity at any level preoperatively. Those who did not RTA reported no activity 2 years after revision. Baseline data included patient characteristics, surgical history and characteristics, and PROs: International Knee Documentation Committee questionnaire, Marx Activity Rating Scale, Knee injury and Osteoarthritis Outcome Score, and the Western Ontario and McMaster Universities Osteoarthritis Index. A binary indicator was used to identify patients with same/better PROs versus worse outcomes compared with baseline, quantifying the magnitude of change in each direction, respectively. Multivariable regression models were used to evaluate risk factors for not returning to activity, the association of 2-year PROs after rACLR surgery by RTA status, and whether each PRO and RTA status differed by participation level., Results: At 2 years postoperatively, approximately 15% did not RTA, with current smokers (adjusted odds ratio [aOR] = 3.3; P = .001), female patients (aOR = 2.9; P < .001), recreational participants (aOR = 2.0; P = .016), and those with a previous medial meniscal excision (aOR = 1.9; P = .013) having higher odds of not returning. In multivariate models, not returning to activity was significantly associated with having worse PROs at 2 years; however, no clinically meaningful differences in PROs at 2 years were seen between participation levels., Conclusion: Recreational-level participants were twice as likely to not RTA compared with those participating at higher levels. Within a previously active cohort, no RTA was a significant predictor of lower PROs after rACLR. However, among patients who did RTA after rACLR, approximately 20% reported lower outcome scores. Most patients with rACLR who were active at baseline improved over time; however, patients who reported worse outcomes at 2 years had a clinically meaningful decline across all PROs.

Background: Tibial bone stress injuries are common among the athletic adolescent population. A thorough patient history and clinical examination are essential to identify the location and extent of injury. However, there has been little description or any validation of clinical tests to help guide clinicians. Consequently, a formal diagnosis is usually dependent on results from proper imaging., Hypothesis: Clinical examinations will be both highly sensitive and specific determining the incidence, grade, and location of tibial bone stress injury as compared with magnetic resonance imaging (MRI)., Study Design: Case-control., Level of Evidence: Level 2., Methods: A total of 80 consecutive athletic adolescents, from various sports, with greater than 1-week history of shin pain were enrolled in this institutional review board-approved study. Exclusion criteria were age >19 years and history of traumatic injury. Patients underwent a standardized clinical examination, which included a fulcrum test (FT), tap/percussion test (TT), vibration test (VT) utilizing a 128-Hz tuning fork, weight bearing lunge test (WBLT) to determine degree of dorsiflexion range of motion (ROM), and vertical single leg hop test (VSLHT) for height, landing, and pain. Bilateral lower extremity MRI was completed on the same day as clinical evaluation and served as the injury reference. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated to evaluate each clinical examination for its ability to identify a bone stress injury., Results: A total of 159 tibiae in 80 patients were evaluated. No single test or combination of tests was both highly sensitive and specific. Individual clinical tests demonstrated sensitivity ranging from 0.11 to 0.72 and specificity ranging from 0.37 to 0.93. The VSLHT noting an increase in pain was the most sensitive test (0.72; 95% CI, 0.62-0.78); however, its specificity was only 0.37 (95% CI, 0.19-0.55), with a PPV of 0.84 (95% CI, 0.78-0.91) and NPV of 0.20 (95% CI, 0.089-0.31). The WBLT demonstrated a mean ROM of 8 cm, with side-to-side differences (range 0-4 cm) not influencing incidence of injury. Combinations of tests demonstrated low sensitivity (0.03-0.40), with better specificity (0.63-1.0). When considering ability to identify higher grades of injury (grade III/IV), all tests had a high NPV indicating that if clinical tests were negative, there was a high likelihood that the patient did not have a grade III or IV injury., Conclusion: No single test or combination of tests was both highly sensitive and specific. Clinicians cannot solely rely on clinical examination for determining extent or severity of bone stress injury in the athletic adolescent population, but when combinations of tests are negative, there is likely not a high-grade bone stress injury., Clinical Relevance: Clinical tests utilized in the evaluation of adolescent tibial bone stress injury may help indicate the presence or absence of higher grade tibial bone stress injury.

Background: Although graft choice may be limited in the revision setting based on previously used grafts, most surgeons believe that graft choice for anterior cruciate ligament (ACL) reconstruction is an important factor related to outcome., Hypothesis: In the ACL revision setting, there would be no difference between autograft and allograft in rerupture rate and patient-reported outcomes (PROs) at 6-year follow-up., Study Design: Cohort study; Level of evidence, 2., Methods: Patients who had revision surgery were identified and prospectively enrolled in this cohort study by 83 surgeons over 52 sites. Data collected included baseline characteristics, surgical technique and pathology, and a series of validated PRO measures. Patients were followed up at 6 years and asked to complete the identical set of PRO instruments. Incidence of additional surgery and reoperation because of graft failure were also recorded. Multivariable regression models were used to determine the predictors (risk factors) of PROs, graft rerupture, and reoperation at 6 years after revision surgery., Results: A total of 1234 patients including 716 (58%) men were enrolled. A total of 325 (26%) underwent revision using a bone-patellar tendon-bone (BTB) autograft; 251 (20%), soft tissue autograft; 289 (23%), BTB allograft; 302 (25%), soft tissue allograft; and 67 (5%), other graft. Questionnaires and telephone follow-up for subsequent surgery information were obtained for 809 (66%) patients, while telephone follow-up was only obtained for an additional 128 patients for the total follow-up on 949 (77%) patients. Graft choice was a significant predictor of 6-year Marx Activity Rating Scale scores ( P = .024). Specifically, patients who received a BTB autograft for revision reconstruction had higher activity levels than did patients who received a BTB allograft (odds ratio [OR], 1.92; 95% CI, 1.25-2.94). Graft rerupture was reported in 5.8% (55/949) of patients by their 6-year follow-up: 3.5% (16/455) of patients with autografts and 8.4% (37/441) of patients with allografts. Use of a BTB autograft for revision resulted in patients being 4.2 times less likely to sustain a subsequent graft rupture than if a BTB allograft were utilized ( P = .011; 95% CI, 1.56-11.27). No significant differences were found in graft rerupture rates between BTB autograft and soft tissue autografts ( P = .87) or between BTB autografts and soft tissue allografts ( P = .36). Use of an autograft was found to be a significant predictor of having fewer reoperations within 6 years compared with using an allograft ( P = .010; OR, 0.56; 95% CI, 0.36-0.87)., Conclusion: BTB and soft tissue autografts had a decreased risk in graft rerupture compared with BTB allografts. BTB autografts were associated with higher activity level than were BTB allografts at 6 years after revision reconstruction. Surgeons and patients should consider this information when choosing a graft for revision ACL reconstruction.

Background: Meniscal preservation has been demonstrated to contribute to long-term knee health. This has been a successful intervention in patients with isolated tears and tears associated with anterior cruciate ligament (ACL) reconstruction. However, the results of meniscal repair in the setting of revision ACL reconstruction have not been documented., Purpose: To examine the prevalence and 2-year operative success rate of meniscal repairs in the revision ACL setting., Study Design: Case-control study; Level of evidence, 3., Methods: All cases of revision ACL reconstruction with concomitant meniscal repair from a multicenter group between 2006 and 2011 were selected. Two-year follow-up was obtained by phone and email to determine whether any subsequent surgery had occurred to either knee since the initial revision ACL reconstruction. If so, operative reports were obtained, whenever possible, to verify the pathologic condition and subsequent treatment., Results: In total, 218 patients (18%) from 1205 revision ACL reconstructions underwent concurrent meniscal repairs. There were 235 repairs performed: 153 medial, 48 lateral, and 17 medial and lateral. The majority of these repairs (n = 178; 76%) were performed with all-inside techniques. Two-year surgical follow-up was obtained on 90% (197/218) of the cohort. Overall, the meniscal repair failure rate was 8.6% (17/197) at 2 years. Of the 17 failures, 15 were medial (13 all-inside, 2 inside-out) and 2 were lateral (both all-inside). Four medial failures were treated in conjunction with a subsequent repeat revision ACL reconstruction., Conclusion: Meniscal repair in the revision ACL reconstruction setting does not have a high failure rate at 2-year follow-up. Failure rates for medial and lateral repairs were both <10% and consistent with success rates of primary ACL reconstruction meniscal repair. Medial tears underwent reoperation for failure at a significantly higher rate than lateral tears.

Background: The incidence of adolescent overuse injuries, including bone stress injuries (BSIs), is on the rise. The identification of a BSI in the early stages is key to successful treatment. The Shin Pain Scoring System (SPSS) was developed to aid clinicians in identifying patients with a BSI., Hypothesis: The SPSS will correlate with magnetic resonance imaging (MRI) grading of a BSI in an adolescent population., Study Design: Cohort study (diagnosis); Level of evidence, 2., Methods: Enrolled in this study were 80 adolescent high school athletes between the ages of 13 and 18 years participating in a variety of sports with more than 1 week of atraumatic shin pain. The SPSS questionnaire was completed for each participant, and physical examination findings were recorded. Each question and physical examination item was allotted a point value, which totaled 29 points. Radiographs and MRI scans of both lower legs were obtained for each participant. The SPSS score was statistically analyzed using logistic regression, a classification matrix, and a 2 × 2 contingency table to evaluate validity and predictability., Results: Logistic regression analysis of our data determined that 3 categories of SPSS scores provided the highest diagnostic value when compared with MRI grading based on the Fredericson classification (0-4). The SPSS correctly identified 43.5% of injuries for category 1 (MRI grades 0-1), 62.5% for category 2 (MRI grade 2), and 50.0% for category 3 (MRI grades 3-4). Overall, the SPSS correctly identified the degree of BSI in 54.4% of all tibias studied. Binary analysis for validity demonstrated a sensitivity of 96%, specificity of 26%, positive predictive value of 76%, and negative predictive value of 71% for the SPSS relative to the "gold standard" MRI results., Conclusion: The SPSS is a potentially valid method to identify tibial BSIs, given the sensitivity and negative and positive predictive values. It also provides helpful categorization to alert clinicians to the presence of a BSI and direct further diagnostics and/or interventions. The SPSS should be considered as an additional tool to use when evaluating adolescents with atraumatic tibial BSIs., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: University Orthopaedic Associates provided free use of their MRI equipment for some of the study participants. C.J.G. has received research support from the Musculoskeletal Transplant Foundation and educational support from Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2019.)

Background: Patient-reported outcomes (PROs) are a valid measure of results after revision anterior cruciate ligament (ACL) reconstruction. Revision ACL reconstruction has been documented to have worse outcomes when compared with primary ACL reconstruction. Understanding positive and negative predictors of PROs will allow surgeons to modify and potentially improve outcome for patients., Purpose/hypothesis: The purpose was to describe PROs after revision ACL reconstruction and test the hypothesis that patient- and technique-specific variables are associated with these outcomes., Study Design: Cohort study; Level of evidence, 2., Methods: Patients undergoing revision ACL reconstruction were identified and prospectively enrolled by 83 surgeons over 52 sites. Data included baseline demographics, surgical technique and pathology, and a series of validated PRO instruments: International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index, and Marx Activity Rating Scale. Patients were followed up at 2 years and asked to complete the identical set of outcome instruments. Multivariate regression models were used to control for a variety of demographic and surgical factors to determine the positive and negative predictors of PRO scores at 2 years after revision surgery., Results: A total of 1205 patients met the inclusion criteria and were successfully enrolled: 697 (58%) were male, with a median cohort age of 26 years. The median time since their most recent previous ACL reconstruction was 3.4 years. Two-year questionnaire follow-up was obtained from 989 patients (82%). The most significant positive predictors of 2-year IKDC scores were a high baseline IKDC score, high baseline Marx activity level, male sex, and having a longer time since the most recent previous ACL reconstruction, while negative predictors included having a lateral meniscectomy before the revision ACL reconstruction or having grade 3/4 chondrosis in either the trochlear groove or the medial tibial plateau at the time of the revision surgery. For KOOS, having a high baseline score and having a longer time between the most recent previous ACL reconstruction and revision surgery were significant positive predictors for having a better (ie, higher) 2-year KOOS, while having a lateral meniscectomy before the revision ACL reconstruction was a consistent predictor for having a significantly worse (ie, lower) 2-year KOOS. Statistically significant positive predictors for 2-year Marx activity levels included higher baseline Marx activity levels, younger age, male sex, and being a nonsmoker. Negative 2-year activity level predictors included having an allograft or a biologic enhancement at the time of revision surgery., Conclusion: PROs after revision ACL reconstruction are associated with a variety of patient- and surgeon-related variables. Understanding positive and negative predictors of PROs will allow surgeons to guide patient expectations as well as potentially improve outcomes.

Background: Anterior cruciate ligament (ACL) revision cohorts continually report lower outcome scores on validated knee questionnaires than primary ACL cohorts at similar time points after surgery. It is unclear how these outcomes are associated with physical activity after physician clearance for return to recreational or competitive sports after ACL revision surgery., Hypotheses: Participants who return to either multiple sports or a singular sport after revision ACL surgery will report decreased knee symptoms, increased activity level, and improved knee function as measured by validated patient-reported outcome measures (PROMs) and compared with no sports participation. Multisport participation as compared with singular sport participation will result in similar increased PROMs and activity level., Study Design: Cross-sectional study; Level of evidence, 3., Methods: A total of 1205 patients who underwent revision ACL reconstruction were enrolled by 83 surgeons at 52 clinical sites. At the time of revision, baseline data collected included the following: demographics, surgical characteristics, previous knee treatment and PROMs, the International Knee Documentation Committee (IKDC) questionnaire, Marx activity score, Knee injury and Osteoarthritis Outcome Score (KOOS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). A series of multivariate regression models were used to evaluate the association of IKDC, KOOS, WOMAC, and Marx Activity Rating Scale scores at 2 years after revision surgery by sports participation category, controlling for known significant covariates., Results: Two-year follow-up was obtained on 82% (986 of 1205) of the original cohort. Patients who reported not participating in sports after revision surgery had lower median PROMs both at baseline and at 2 years as compared with patients who participated in either a single sport or multiple sports. Significant differences were found in the change of scores among groups on the IKDC ( P < .0001), KOOS-Symptoms ( P = .01), KOOS-Sports and Recreation ( P = .04), and KOOS-Quality of Life ( P < .0001). Patients with no sports participation were 2.0 to 5.7 times more likely than multiple-sport participants to report significantly lower PROMs, depending on the specific outcome measure assessed, and 1.8 to 3.8 times more likely than single-sport participants (except for WOMAC-Stiffness, P = .18), after controlling for known covariates., Conclusion: Participation in either a single sport or multiple sports in the 2 years after ACL revision surgery was found to be significantly associated with higher PROMs across multiple validated self-reported assessment tools. During follow-up appointments, surgeons should continue to expect that patients who report returning to physical activity after surgery will self-report better functional outcomes, regardless of baseline activity levels.

Background: Bony stress injuries (BSIs) are common among adolescents involved in high school sports. A better understanding of factors that contribute to adolescent BSI is needed to target preventative measures., Hypothesis: Individuals who suffer a BSI will demonstrate significant differences in training methods, sleep, diet, and history of injury compared with a healthy, noninjured control group., Study Design: Descriptive epidemiologic study., Methods: Data from the National High School Stress Fracture Registry (NHSSFR), an internet-based adolescent BSI survey, were used to identify variables reported with adolescent (13-18 years of age) BSI. These findings were compared with a survey of 100 (50 males, 50 females) healthy athletic controls to identify significant differences between healthy adolescents and those with BSI., Results: A total of 346 stress fractures were reported in 314 (206 females, 108 males) athletes within the NHSSFR. Comparison with healthy control participants demonstrated multiple significant findings. In particular, body mass index was significantly lower for patients with BSI injury compared with controls ( P < 0.001). Patients slept significantly less than the control group (7.2 vs 7.95 hours; F = 34.41; P < 0.001). Females also slept significantly less hours than males (7.2 vs 7.63 hours; F = 11.02; P < 0.001). Fifty-eight percent of those who reported a BSI did not engage in any weight training. Those with a BSI had significantly higher average stress ratings than control participants (1.67 vs 1.42; P < 0.001), and females also rated their stress levels significantly higher than males (1.8 vs 1.38; P < 0.001). A significant difference between patients with any BSI and control participants existed for history of "shin splints" (Pearson χ 2 = 28.31; P < 0.001), and females also expressed having shin pain lasting for longer than 4 weeks (Pearson χ 2 = 8.12; P < 0.001) and more often (Pearson χ 2 = 5.84; P = 0.02) than males. There was also a significant difference between patients with BSI and control subjects regarding dairy intake (2.25 vs 2.69; F = 6.43; P = 0.01)., Conclusion: Findings revealed significant differences between those who reported a BSI relative to healthy athletic adolescents. These differences included body mass index, prior history of shin splints, involvement in weight training, amount of sleep, daily stress, and dairy intake. Preventive measures should be developed to address these areas to reduce the incidence of BSIs in the adolescent population.

Background: The occurrence of physiologic knee hyperextension (HE) in the revision anterior cruciate ligament reconstruction (ACLR) population and its effect on outcomes have yet to be reported. Hypothesis/Purpose: The prevalence of knee HE in revision ACLR and its effect on 2-year outcome were studied with the hypothesis that preoperative physiologic knee HE ≥5° is a risk factor for anterior cruciate ligament (ACL) graft rupture., Study Design: Cohort study; Level of evidence, 2., Methods: Patients undergoing revision ACLR were identified and prospectively enrolled between 2006 and 2011. Study inclusion criteria were patients undergoing single-bundle graft reconstructions. Patients were followed up at 2 years and asked to complete an identical set of outcome instruments (International Knee Documentation Committee, Knee injury and Osteoarthritis Outcome Score, WOMAC, and Marx Activity Rating Scale) as well as provide information regarding revision ACL graft failure. A regression model with graft failure as the dependent variable included age, sex, graft type at the time of the revision ACL surgery, and physiologic preoperative passive HE ≥5° (yes/no) to assess these as potential risk factors for clinical outcomes 2 years after revision ACLR., Results: Analyses included 1145 patients, for whom 2-year follow-up was attained for 91%. The median age was 26 years, with age being a continuous variable. Those below the median were grouped as "younger" and those above as "older" (age: interquartile range = 20, 35 years), and 42% of patients were female. There were 50% autografts, 48% allografts, and 2% that had a combination of autograft plus allograft. Passive knee HE ≥5° was present in 374 (33%) patients in the revision cohort, with 52% being female. Graft rupture at 2-year follow-up occurred in 34 cases in the entire cohort, of which 12 were in the HE ≥5° group (3.2% failure rate) and 22 in the non-HE group (2.9% failure rate). The median age of patients who failed was 19 years, as opposed to 26 years for those with intact grafts. Three variables in the regression model were significant predictors of graft failure: younger age (odds ratio [OR] = 3.6; 95% CI, 1.6-7.9; P = .002), use of allograft (OR = 3.3; 95% CI, 1.5-7.4; P = .003), and HE ≥5° (OR = 2.12; 95% CI, 1.1-4.7; P = .03)., Conclusion: This study revealed that preoperative physiologic passive knee HE ≥5° is present in one-third of patients who undergo revision ACLR. HE ≥5° was an independent significant predictor of graft failure after revision ACLR with a >2-fold OR of subsequent graft rupture in revision ACL surgery. Registration: NCT00625885 ( ClinicalTrials.gov identifier).

Background: Meniscus injuries and associated meniscectomies cause patients long-term pain and discomfort and can lead to joint deterioration., Purpose: To evaluate a collagen-hyaluronan sponge reinforced with synthetic resorbable polymer fiber for total meniscus reconstruction in a long-term ovine model., Study Design: Controlled laboratory study., Methods: Eleven skeletally mature sheep were implanted with the total meniscus scaffold. At 2 years, explants were evaluated biologically (radial/circumferential histology, immunofluorescence) and mechanically (compression, tension), and articular surfaces were examined for damage., Results: The fiber-reinforced scaffold induced formation of functional neomeniscus tissue that was intact in 8 of 11 animals. The implant was remodeled into organized circumferentially aligned collagen bundles to resist meniscus hoop stresses. Moreover, type II collagen and proteoglycan deposition near the inner margin suggested a direct response to compressive stresses and confirmed fibrocartilage formation. Cartilage damage was observed, but end-stage (severe) joint deterioration associated with meniscectomy was avoided, even with limitations regarding the ovine surgical procedure and postoperative care., Conclusion: A fiber-reinforced total meniscus replacement device induces formation of functional neomeniscus tissue that has the potential to prevent catastrophic joint deterioration associated with meniscectomy., Clinical Relevance: An off-the-shelf meniscus device that can be remodeled into functional tissue and thus prevent or delay the onset of osteoarthritis could address a widespread clinical need after meniscus injury.

Background: Meniscal lesions represent one of the most common intra-articular knee injuries. Meniscus replacement devices are needed to restore load distribution and knee stability after meniscectomy. Fixation of these devices is crucial to the generation of hoop stresses and the distribution of loads in the joint., Purpose: To evaluate 2 different fixation techniques (suture endobutton and interference screw) for implantation of a novel meniscus device., Study Design: Controlled laboratory study., Methods: In 7 human cadaveric knees (aged 17-61 years), 1 anterior and 2 potential posterior tunnel locations were investigated, and both fixation techniques were tested in each tunnel. The native meniscus roots, devices fixed with a suture endobutton, and devices fixed with an interference screw were gripped with cryoclamps, and tibias were drilled and loaded into a custom jig. Samples were preloaded, preconditioned, loaded for 500 cycles (50-150 N), and tested in tension until failure., Results: For all 3 tunnels, suture fixation resulted in greater elongation (54.1%-150.7% greater; P < .05) during cyclic loading than interference screw fixation, which approximated the native roots. Both fixation techniques displayed ultimate tensile loads in the same range as native roots. However, stiffness of the suture fixation groups (36.5-41.6 N/mm) was only 28% to 37% of that of the interference screw fixation groups (98.7-131.6 N/mm), which had values approaching those of the native roots (anterior: 175.4 ± 24.2 N/mm; posterior: 157.6 ± 22.9 N/mm)., Conclusion: Interference screw fixation was found to be superior to suture fixation with regard to elongation and stiffness, a finding that should be considered in the design and implantation of novel meniscus replacement devices., Clinical Relevance: With the emergence of various devices for total meniscus replacement, the establishment of fixation strategies is crucial for the generation of tensile hoop stresses and the efficacy of these approaches.

Background: Articular cartilage health is an important issue following anterior cruciate ligament (ACL) injury and primary ACL reconstruction. Factors present at the time of primary ACL reconstruction may influence the subsequent progression of articular cartilage damage., Hypothesis: Larger meniscus resection at primary ACL reconstruction, increased patient age, and increased body mass index (BMI) are associated with increased odds of worsened articular cartilage damage at the time of revision ACL reconstruction., Study Design: Case-control study; Level of evidence, 3., Methods: Subjects who had primary and revision data in the databases of the Multicenter Orthopaedics Outcomes Network (MOON) and Multicenter ACL Revision Study (MARS) were included. Reviewed data included chondral surface status at the time of primary and revision surgery, meniscus status at the time of primary reconstruction, primary reconstruction graft type, time from primary to revision ACL surgery, as well as demographics and Marx activity score at the time of revision. Significant progression of articular cartilage damage was defined in each compartment according to progression on the modified Outerbridge scale (increase ≥1 grade) or >25% enlargement in any area of damage. Logistic regression identified predictors of significant chondral surface change in each compartment from primary to revision surgery., Results: A total of 134 patients were included, with a median age of 19.5 years at revision surgery. Progression of articular cartilage damage was noted in 34 patients (25.4%) in the lateral compartment, 32 (23.9%) in the medial compartment, and 31 (23.1%) in the patellofemoral compartment. For the lateral compartment, patients who had >33% of the lateral meniscus excised at primary reconstruction had 16.9-times greater odds of progression of articular cartilage injury than those with an intact lateral meniscus ( P < .001). For the medial compartment, patients who had <33% of the medial meniscus excised at the time of the primary reconstruction had 4.8-times greater odds of progression of articular cartilage injury than those with an intact medial meniscus ( P = .02). Odds of significant chondral surface change increased by 5% in the lateral compartment and 6% in the medial compartment for each increased year of age ( P ≤ .02). For the patellofemoral compartment, the use of allograft in primary reconstruction was associated with a 15-fold increased odds of progression of articular cartilage damage relative to a patellar tendon autograft ( P < .001). Each 1-unit increase in BMI at the time of revision surgery was associated with a 10% increase in the odds of progression of articular cartilage damage ( P = .046) in the patellofemoral compartment., Conclusion: Excision of the medial and lateral meniscus at primary ACL reconstruction increases the odds of articular cartilage damage in the corresponding compartment at the time of revision ACL reconstruction. Increased age is a risk factor for deterioration of articular cartilage in both tibiofemoral compartments, while increased BMI and the use of allograft for primary ACL reconstruction are associated with an increased risk of progression in the patellofemoral compartment.

Background: Revision anterior cruciate ligament (ACL) reconstruction has been documented to have worse outcomes compared with primary ACL reconstruction., Hypothesis: Certain factors under the control of the surgeon at the time of revision surgery can both negatively and positively affect outcomes., Study Design: Case-control study; Level of evidence, 3., Methods: Patients undergoing revision ACL reconstruction were identified and prospectively enrolled between 2006 and 2011. Data collected included baseline demographics, intraoperative surgical technique and joint disorders, and a series of validated patient-reported outcome instruments (International Knee Documentation Committee [IKDC] subjective form, Knee Injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Marx activity rating scale) completed before surgery. Patients were followed up for 2 years and asked to complete an identical set of outcome instruments. Regression analysis was used to control for age, sex, body mass index (BMI), activity level, baseline outcome scores, revision number, time since last ACL reconstruction, and a variety of previous and current surgical variables to assess the surgical risk factors for clinical outcomes 2 years after revision ACL reconstruction., Results: A total of 1205 patients (697 male [58%]) met the inclusion criteria and were successfully enrolled. The median age was 26 years, and the median time since their last ACL reconstruction was 3.4 years. Two-year follow-up was obtained on 82% (989/1205). Both previous and current surgical factors were found to be significant contributors toward poorer clinical outcomes at 2 years. Having undergone previous arthrotomy (nonarthroscopic open approach) for ACL reconstruction compared with the 1-incision technique resulted in significantly poorer outcomes for the 2-year IKDC ( P = .037; odds ratio [OR], 2.43; 95% CI, 1.05-5.88) and KOOS pain, sports/recreation, and quality of life (QOL) subscales ( P ≤ .05; OR range, 2.38-4.35; 95% CI, 1.03-10.00). The use of a metal interference screw for current femoral fixation resulted in significantly better outcomes for the 2-year KOOS symptoms, pain, and QOL subscales ( P ≤ .05; OR range, 1.70-1.96; 95% CI, 1.00-3.33) as well as WOMAC stiffness subscale ( P = .041; OR, 1.75; 95% CI, 1.02-3.03). Not performing notchplasty at revision significantly improved 2-year outcomes for the IKDC ( P = .013; OR, 1.47; 95% CI, 1.08-1.99), KOOS activities of daily living (ADL) and QOL subscales ( P ≤ .04; OR range, 1.40-1.41; 95% CI, 1.03-1.93), and WOMAC stiffness and ADL subscales ( P ≤ .04; OR range, 1.41-1.49; 95% CI, 1.03-2.05). Factors before revision ACL reconstruction that increased the risk of poorer clinical outcomes at 2 years included lower baseline outcome scores, a lower Marx activity score at the time of revision, a higher BMI, female sex, and a shorter time since the patient's last ACL reconstruction. Prior femoral fixation, prior femoral tunnel aperture position, and knee flexion angle at the time of revision graft fixation were not found to affect 2-year outcomes in this revision cohort., Conclusion: There are certain surgical variables that the physician can control at the time of revision ACL reconstruction that can modify clinical outcomes at 2 years. Whenever possible, opting for an anteromedial portal or transtibial surgical exposure, choosing a metal interference screw for femoral fixation, and not performing notchplasty are associated with significantly better 2-year clinical outcomes.

Background: While revision anterior cruciate ligament reconstruction (ACLR) can be performed to restore knee stability and improve patient activity levels, outcomes after this surgery are reported to be inferior to those after primary ACLR. Further reoperations after revision ACLR can have an even more profound effect on patient satisfaction and outcomes. However, there is a current lack of information regarding the rate and risk factors for subsequent surgery after revision ACLR., Purpose: To report the rate of reoperations, procedures performed, and risk factors for a reoperation 2 years after revision ACLR., Study Design: Case-control study; Level of evidence, 3., Methods: A total of 1205 patients who underwent revision ACLR were enrolled in the Multicenter ACL Revision Study (MARS) between 2006 and 2011, composing the prospective cohort. Two-year questionnaire follow-up was obtained for 989 patients (82%), while telephone follow-up was obtained for 1112 patients (92%). If a patient reported having undergone subsequent surgery, operative reports detailing the subsequent procedure(s) were obtained and categorized. Multivariate regression analysis was performed to determine independent risk factors for a reoperation., Results: Of the 1112 patients included in the analysis, 122 patients (11%) underwent a total of 172 subsequent procedures on the ipsilateral knee at 2-year follow-up. Of the reoperations, 27% were meniscal procedures (69% meniscectomy, 26% repair), 19% were subsequent revision ACLR, 17% were cartilage procedures (61% chondroplasty, 17% microfracture, 13% mosaicplasty), 11% were hardware removal, and 9% were procedures for arthrofibrosis. Multivariate analysis revealed that patients aged <20 years had twice the odds of patients aged 20 to 29 years to undergo a reoperation. The use of an allograft at the time of revision ACLR (odds ratio [OR], 1.79; P = .007) was a significant predictor for reoperations at 2 years, while staged revision (bone grafting of tunnels before revision ACLR) (OR, 1.93; P = .052) did not reach significance. Patients with grade 4 cartilage damage seen during revision ACLR were 78% less likely to undergo subsequent operations within 2 years. Sex, body mass index, smoking history, Marx activity score, technique for femoral tunnel placement, and meniscal tearing or meniscal treatment at the time of revision ACLR showed no significant effect on the reoperation rate., Conclusion: There was a significant reoperation rate after revision ACLR at 2 years (11%), with meniscal procedures most commonly involved. Independent risk factors for subsequent surgery on the ipsilateral knee included age <20 years and the use of allograft tissue at the time of revision ACLR.

Our objective was to test the efficacy of collagen-hyaluronan scaffolds reinforced with poly(l-lactic acid) (PLLA) fibers in an ovine total meniscus replacement model. Scaffolds were implanted into 9 sheep (n = 1 at 8 weeks, n = 2 at 16 weeks, n = 3 at both 24, 32 weeks) following total medial meniscectomy. From 16 weeks on, explants were characterized by confined compression creep, histological, and biochemical analyses. Articular surfaces were observed macroscopically and damage was ranked histologically using the Mankin score. At sacrifice, three of the nine PLLA scaffolds had completely ruptured, and the intact scaffolds experienced progressive shape changes and severe narrowing in the body region at 16, 24, and 32 weeks. Aggregate compressive modulus and permeability did not improve with time. Histological and biochemical analyses showed significantly less extracellular matrix and less matrix organization compared to native tissue. Osteophytes, bone erosion, and cartilage damage were observed, increasing with time postimplantation. A buildup of lactic acid and/or the rapid loss of scaffold mechanical integrity due to PLLA degradation are probable causes for the joint abnormalities observed in this study. These results are in sharp contrast to those of our previous successful total meniscus replacement studies using polyarylate [p(DTD DD)] fiber-reinforced scaffolds. This suggests that PLLA fiber as produced in this study cannot be used as reinforcement for a meniscus replacement scaffold.

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., (© 2016 The Author(s).)

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., (© 2015 The Author(s).)

Purpose: The purposes of this systematic review were (1) to determine whether there is a minimum hamstring autograft size for anterior cruciate ligament (ACL) reconstruction that significantly decreases the risk of failure and (2) to evaluate the methods to accurately and reliably predict the size of hamstring grafts., Methods: We performed a systematic review of Level III and IV studies using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. All studies assessing failure of quadrupled-strand autograft hamstring ACL reconstruction as a function of graft diameter with at least 1 year of follow-up and those that assessed the use of imaging or anthropometric patient-specific factors to predict hamstring autograft size were included., Results: We identified 4 clinical studies that directly compared graft size and failure rate. These correlated with a 6.8 times greater relative risk of failure if the graft diameter was equal to or less than 8 mm (P = .008). All 9 anthropometric-based prediction studies were able to significantly correlate at least 1 parameter with intraoperative graft size. Height was the most common correlation, with r = 0.45 (P < .00001). Five of 6 imaging-based prediction studies showed signification correlation, with r = 0.66 (P < .00001), between cross-sectional area and graft size. The most common method of imaging prediction was magnetic resonance imaging-derived cross-sectional area of both the semitendinosus and gracilis tendons., Conclusions: On the basis of the available evidence, ACL reconstruction with a quadrupled-strand hamstring autograft with a diameter equal to or larger than 8 mm decreases failure rates. In addition, grafts larger than 8 mm decrease failure rates in patients aged younger than 20 years, a group identified to be at increased risk of failure. Both patient height and magnetic resonance imaging-derived cross-sectional area of the hamstring tendons can be used preoperatively to reliably predict the hamstring autograft diameter., Level of Evidence: Level IV, systematic review of Level III and IV studies., (Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Successful protection of tissue properties against ionizing radiation effects could allow its use for terminal sterilization of musculoskeletal allografts. In this study we functionally evaluate Achilles tendon allografts processed with a previously developed radioprotective treatment based on (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) crosslinking and free radical scavenging using ascorbate and riboflavin, for ovine anterior cruciate ligament reconstruction. Arthroscopic anterior cruciate ligament (ACL) reconstruction was performed using double looped allografts, while comparing radioprotected irradiated and fresh frozen allografts after 12 and 24 weeks post-implantation, and to control irradiated grafts after 12 weeks. Radioprotection was successful at preserving early subfailure mechanical properties comparable to fresh frozen allografts. Twelve week graft stiffness and anterior-tibial (A-T) translation for radioprotected and fresh frozen allografts were comparable at 30 % of native stiffness, and 4.6 and 5 times native A-T translation, respectively. Fresh frozen allograft possessed the greatest 24 week peak load at 840 N and stiffness at 177 N/mm. Histological evidence suggested a delay in tendon to bone healing for radioprotected allografts, which was reflected in mechanical properties. There was no evidence that radioprotective treatment inhibited intra-articular graft healing. This specific radioprotective method cannot be recommended for ACL reconstruction allografts, and data suggest that future efforts to improve allograft sterilization procedures should focus on modifying or eliminating the pre-crosslinking procedure.

Terminal sterilization of tendon allografts with high dose gamma irradiation has deleterious effects on tendon mechanical properties and stability after implantation. Our goal is to minimize these effects with radio protective methods. We previously showed that radio protection via combined crosslinking and free radical scavenging maintained initial mechanical properties of tendon allografts after irradiation at 50 kGy. This study further evaluates the tissue response and simulated mechanical degradation of tendons processed with radio protective treatment, which involves crosslinking in 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide followed by soaking in an ascorbate/riboflavin-5-phosphate solution. Control untreated and treated tendons were irradiated at 50 kGy and implanted in New Zealand White rabbit knees within the joint capsule for four and 8 weeks. Tendons were also exposed to cyclic loading to 20 N at one cycle per 12 s in a collagenase solution for 150 cycles, followed by tension to failure. Control irradiated tendons displayed increased degradation in vivo, and failed prematurely during cyclic processing at an average of 25 cycles. In contrast, radio protected irradiated tendons displayed greater stability following implantation over 8 weeks, and possessed strength at 59 % of native tendons and modulus equivalent to that of native tendons after cyclic loading in collagenase. These results suggest that radio protective treatment improves the strength and the stability of tendon allografts.

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., (Copyright © 2011 Wiley Periodicals, Inc.)

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 BUSS's capability to discriminate between stages of bone atrophy and in particular to distinguish early changes induced by osteoporosis.

Objective: Collagenase-3, a matrix metalloproteinase (MMP-13) that can degrade collagen II and aggrecan, is produced by osteoarthritic (OA) chondrocytes and may contribute to matrix destruction in this disease. Our laboratory has previously identified a specific endocytotic receptor for collagenase-3 on osteoblastic and fibroblastic cells, which couples with the low-density lipoprotein receptor-related protein (LRP1) to mediate the internalization and degradation of this enzyme. We hypothesized that the activity of this receptor system is reduced in OA chondrocytes which may lead to increased local extracellular levels of collagenase-3 and increased destruction of the cartilage matrix at pericellular sites., Methods: Human chondrocytes and synoviocytes were obtained from OA knees at the time of joint replacement surgery and from non-arthritic control specimens following autopsy or surgery. Enzyme-linked immunosorbant assay (ELISA) was used to measure collagenase-3 secreted from primary cultures. Iodinated collagenase-3 was used to analyze the cell-surface binding, internalization and intracellular degradation of collagenase-3. Reverse-transcriptase polymerase chain reaction was used to confirm chondrocyte phenotype and the expression of collagenase-3 and LRP1 mRNAs., Results: OA chondrocytes and synoviocytes demonstrated significantly reduced (75-77%) binding of recombinant 125I collagenase-3. Internalization and degradation of the ligand was also significantly reduced (64-72%) in OA cells. Collagenase-3 removal was inhibited by the LRP1 receptor-associated protein (RAP)., Conclusion: These results suggest a mechanism whereby impaired receptor-mediated removal of collagenase-3 in OA chondrocytes may lead to enhanced local degradation of the cartilage matrix. This work also implicates an LRP family member in endocytotic receptor-mediated collagenase-3 processing and suggests a novel therapeutic target for OA.

This study characterized knee joint kinetics during a golf swing and determined the influence of shoe type and golfer skill on the peak knee joint loads. Thirteen golfers each hit a golf ball using a five iron under two footware conditions: spiked and spikeless golf shoes. Data from a video-based motion capture system and force plates were used to compute the knee joint kinetics. Mean peak forces and moments differed significantly between the lead and trail knees, but these peak loads were not significantly affected by shoe type. Only the lead knee flexion and internal rotation moments were significantly correlated to skill level. The magnitude of some of the peak loads at the knee during the golf swing approached those reached during activities prohibited until late-stage knee rehabilitation. We concluded the following: The type of shoe worn and the skill level of the golfer need not be considered in deciding time to return to golfing; however, the leg that is recovering from surgery or injury should be considered. The most stressful phase of the golf swing, relative to the knee, is the downswing. There is probably no "normal" swing; each golfer seems to possess consistent, characteristic, patterns of knee loading.

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 football 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 responsible for the increased incidence of lumbar spine injury incurred by football linemen.

Although golfing is generally considered a begin activity, lower back pain is endemic among golfers. The golf swing subjects the lumbar spine to rapid, intense loads, more frequently in amateurs than in professionals. These loads predispose the golfing population to muscle strains, lumbar disc disease, spondylolysis, and facet joint arthropathy. It is imperative for all golfers to warm up properly, develop good swing mechanics, and participate in a lower back conditioning program off the golf course.