Fibrin Clots Maintain the Viability and Proliferative Capacity of Human Mesenchymal Stem Cells: An In Vitro Study.

BACKGROUND: Augmentation of soft-tissue repairs with an autologous fibrin clot has been used clinically for nearly four decades; however, fibrin clots tend to produce an abundance of scar tissue, which is known to inhibit soft-tissue regeneration. Mesenchymal stem cells (MSCs) embedded in fibrin clots before repair could reduce scar tissue deposition and facilitate soft-tissue regeneration. To our knowledge, no published studies have directly evaluated the viability or bioactivity of MSCs in fresh human fibrin clots over time. The purpose of this study was to evaluate the viability and bioactivity of human MSCs inside human fibrin clots over time in nutritive and non-nutritive culture media. QUESTIONS/PURPOSES: We hypothesized that human MSCs would (1) be captured inside fibrin clots and retain their proliferative capacity, (2) remain viable for at least 7 days in the fibrin clots, (3) maintain their proliferative capacity for at least 7 days in the fibrin clots without evidence of active apoptosis, and (4) display similar viability and proliferative capacity when cultured in a non-nutritive medium over the same time periods. METHODS: Twelve patients (mean age 33.7 years; range 4-72 years) who underwent elective knee surgery were approached between February 2016 and October 2017; all patients agreed to participate and were enrolled. MSCs isolated from human skeletal muscle and banked after prior studies were used for this analysis. On the day of surgery and after expansion of the MSC population, 3-mL aliquots of phosphate-buffered saline containing approximately 600,000 labeled with anti-green fluorescent protein (GFP) antibodies were transported to the operating room, mixed in 30 mL of venous blood from each enrolled patient, and stirred at 95 rpm for 10 minutes to create MSC-embedded fibrin clots. The fibrin clots were transported to the laboratory with their residual blood for analysis. Eleven samples were analyzed after exclusion of one sample because of a processing error. MSC capture was qualitatively demonstrated by enzymatically digesting half of each clot specimen, thus releasing GFP-positive MSCs into culture. The released MSCs were allowed to culture for 7 days. Manual counting of GFP-positive MSCs was performed at 2, 3, 4, and 7 days using an inverted microscope at 100 x magnification to document the change in the number of GFP-positive MSCs over time. The intact remaining half of each clot specimen was immediately placed in proliferation media and allowed to culture for 7 days. On Days 1, 2, 3, 4, and 7, a small portion of the clot was excised, flash-frozen, cryosectioned (8-µm thickness), and immunostained with antibodies specific to GFP, Ki67 (indicative of active proliferation), and cleaved caspase-3 ([CC3]; indicative of active apoptosis). Using an inverted microscope, we obtained MSC cell counts manually at time zero and after 1, 2, 3, 4, and 7 days of culture. Intact fresh clot specimens were immediately divided in half; one half was placed in nutritive (proliferation media) and the other was placed in non-nutritive (saline) media for 1, 2, 3, 4, and 7 days. At each timepoint, specimens were processed in an identical manner as described above, and a portion of each clot specimen was excised, immediately flash-frozen with liquid nitrogen, cryosectioned (8-µm thickness), and visualized at 200 x using an inverted microscope. The numbers of stain-positive MSCs per field of view, per culture condition, per timepoint, and per antibody stain type were counted manually for a quantitative analysis. Raw data were statistically compared using t-tests, and time-based correlations were assessed using Pearson's correlation coefficients. Two-tailed p values of less than 0.05 (assuming unequal variance) were considered statistically significant. RESULTS: Green fluorescence, indicative of viable GFP-positive MSCs, was absent in all residual blood samples after 48 hours of culturing; GFP-positive MSCs were visualized after enzymatic digestion of clot matrices. The number of GFP-positive MSCs per field of view increased between the 2-day and 7-day timepoints (mean 5.4 ± 1.5; 95% confidence interval, 4.7-6.1 versus mean 17.0 ± 13.6; 95% CI, 10.4-23.5, respectively; p = 0.029). Viable GFP-positive MSCs were present in each clot cryosection at each timepoint up to 7 days of culturing (mean 6.2 ± 4.3; 95% CI, 5.8-6.6). There were no differences in MSC counts between any of the timepoints. There was no visible evidence of GFP +/CC3 + double-positive MSCs. Combining all timepoints, there were 0.34 ± 0.70 (95% CI, 0.25-0.43) GFP+/Ki67+ double-positive MSCs per field of view. The mitotic indices at time zero and Day 7 were 7.5% ± 13.4% (95% CI, 3.0%-12.0%) and 7.2% ± 14.3% (95% CI, 3.3%-12,1%), respectively (p = 0.923). There was no visible evidence of GFP +/CC3 + double-positive MSCs (active apoptosis) at any timepoint. For active proliferation in saline-cultured fibrin clots, we found averages of 0.1 ± 0.3 (95% CI, 0.0-0.2) and 0.4 ± 0.9 (95% CI, 0.0-0.8) GFP/Ki67 double-positive MSCs at time zero and Day 7, respectively (p = 0.499). The mitotic indices in saline culture at time zero and Day 7 were 2.9% ± 8.4% (95% CI, 0.0%-5.8%) and 9.1% ± 20.7% (95% CI, 1.2%-17.0%; p = 0.144). There was no visible evidence of GFP +/CC3 + double-positive MSCs (active apoptosis) at any timepoint in either culturing condition. CONCLUSION: These preliminary in vitro results show that human MSCs mixed in unclotted fresh human venous blood were nearly completely captured in fibrin clots and that seeded MSCs were capable of maintaining their viability, proliferation capacity, and osteogenic differentiation capacity in the fibrin clot for up to 7 days, independent of external sources of nutrition. CLINICAL RELEVANCE: Fresh human fibrin clots have been used clinically for more than 30 years to improve soft-tissue healing, albeit with scar tissue. Our results demonstrate that allogenic human MSCs, which reduce soft-tissue scarring, can be captured and remain active inside human fibrin clots, even in the absence a nutritive culture medium.

Editorial Commentary: Will Suture Tape Augmentation Prove to Be the Answer to Anterior Cruciate Ligament Graft Remodeling, Ultimate Strength, and Safe Return to Play?

Anterior cruciate ligament graft augmentation may protect the graft during the early phases of graft remodeling. A concern is stress-shielding, and recent time-zero biomechanical models are promising in this regard. To get the best answer, it will require in vivo healing studies conducted in animals, and eventually human studies using non-invasive imaging techniques, and ultimately clinical outcome studies including evaluation of return to play in athletes. For now, until additional research studies are available, this type of augmentation is best reserved as an option in carefully selected patients with a small graft size at the time of harvest.

Does Lateral Extra-articular Tenodesis of the Knee Affect Anterior Cruciate Ligament Graft In Situ Forces and Tibiofemoral Contact Pressures?

PURPOSE: To quantify the effects of lateral extra-articular tenodesis (LET) on tibiofemoral compartment contact area and pressures, knee kinematics, and forces. METHODS: Nine cadaveric knees were tested using a robotic testing system. Two loading conditions, (1) anterior tibial translational load coupled with axial compression and (2) internal tibial torque coupled with axial compression, were applied for each knee state at full extension and 30°, 60°, and 90° of knee flexion. Kinematic data was recorded for 3 knee states: anterolateral capsule (ALC) competent, ALC deficient, and post-LET using a 6-mm semitendinosus graft. In situ force in the anterior cruciate ligament (ACL) was quantified using the principle of superposition by comparing the change in force measured before and after the removal of the ALC. Contact area and pressures in each tibiofemoral compartment were measured by replaying kinematics after soft tissues were removed and pressure sensors were inserted. RESULTS: In response to an anterior tibial translational load, mean contact area in the medial compartment decreased by 33.1% from the ALC-competent to post-LET knee states at 90° of knee flexion (P = .042). No significant differences in lateral compartment contact pressure were found between knee states. In situ force in the ACL in response to an anterior tibial translational load decreased by 43.4% and 50% from the ALC-deficient to post-LET knee states at 60° (P = .02) and 90° (P = .006). No significant difference in kinematics was observed between the ALC-competent and post-LET knee states in each of the loading conditions at all knee flexion angles (P > .05). CONCLUSIONS: In this in vitro model, LET with a semitendinosus graft did not significantly overconstrain the knee or increase pressure in the lateral compartment. Additionally, LET reduced the in situ force in the ACL in the setting of ALC injury. CLINICAL RELEVANCE: The lack of knee overconstraint without significant increases in lateral compartment pressures indicates that if an LET with semitendinosus graft is not overtensioned, accelerated degenerative changes in the lateral compartment may not be expected after this procedure.

Editorial Commentary: Déjà Vu: Double-Bundle Anterior Cruciate Ligament Reconstruction Revisited.

Regardless of the technique utilized, tunnel expansion following anterior cruciate ligament reconstruction remains a mystery and a clinical challenge. No procedure seems to be immune to this, even anatomic double-bundle reconstruction. This technique was introduced more than 20 years ago and showed great promise while also contributing significantly to our current knowledge of anterior cruciate ligament anatomy and biomechanics. However, we must remember that new techniques do carry with them new side effects that we must document and acknowledge if we hope to improve our surgical outcomes.

Editorial Commentary: Posterolateral Corner Injuries in Elite Athletes Remain a Challenging Diagnostic Problem.

Posterolateral corner injuries are rare, and the examination to quantitate these injuries is very challenging. Careful examination comparing the involved and uninvolved knees, considering stress radiographs, and combining this with magnetic resonance imaging findings is currently our most accurate way to grade these injuries.

Subject-specific finite element modeling of the tibiofemoral joint based on CT, magnetic resonance imaging and dynamic stereo-radiography data in vivo.

In this paper, we present a new methodology for subject-specific finite element modeling of the tibiofemoral joint based on in vivo computed tomography (CT), magnetic resonance imaging (MRI), and dynamic stereo-radiography (DSX) data. We implemented and compared two techniques to incorporate in vivo skeletal kinematics as boundary conditions: one used MRI-measured tibiofemoral kinematics in a nonweight-bearing supine position and allowed five degrees of freedom (excluding flexion-extension) at the joint in response to an axially applied force; the other used DSX-measured tibiofemoral kinematics in a weight-bearing standing position and permitted only axial translation in response to the same force. Verification and comparison of the model predictions employed data from a meniscus transplantation study subject with a meniscectomized and an intact knee. The model-predicted cartilage-cartilage contact areas were examined against "benchmarks" from a novel in situ contact area analysis (ISCAA) in which the intersection volume between nondeformed femoral and tibial cartilage was characterized to determine the contact. The results showed that the DSX-based model predicted contact areas in close alignment with the benchmarks, and outperformed the MRI-based model: the contact centroid predicted by the former was on average 85% closer to the benchmark location. The DSX-based FE model predictions also indicated that the (lateral) meniscectomy increased the contact area in the lateral compartment and increased the maximum contact pressure and maximum compressive stress in both compartments. We discuss the importance of accurate, task-specific skeletal kinematics in subject-specific FE modeling, along with the effects of simplifying assumptions and limitations.

Progression of patellar tendinitis following treatment with platelet-rich plasma: case reports.

PURPOSE: The use of platelet-rich plasma (PRP) is becoming more attractive given its favourable side effect profile and autologous nature, leading to rapid clinical adoption in the absence of high-level evidence. We are presenting three patients who developed a progression of patellar tendinitis following treatment, which to our knowledge is the first report of worsening of patellar tendinitis following PRP therapy. METHODS: The records of three patients with symptom exacerbation of patellar tendinitis following treatment with PRP were reviewed. IRB exemption was obtained. Clinical and operative records, radiographs, and MR imaging were reviewed for all patients. RESULTS: Three patients reported to our clinic for a second opinion with symptoms of anterior knee pain consistent with patellar tendinitis. Each patient had previously been treated with PRP therapy due to prolonged symptoms. Clinical and radiological findings following treatment included patellar tendon thickening, worsening pain, discontinuation of athletic participation in all three patients, and osteolysis of the distal pole of the patella in one patient identified during surgical intervention. CONCLUSIONS: Growing interest in the use of autologous products for the management of chronic tendinopathies has led to widespread clinical implementation with minimal scientific support. It is tempting to apply a new treatment for management of a difficult clinical entity, especially when the risk/benefit ratio appears favourable. However, caution must be exercised as unexpected results may be encountered. LEVEL OF EVIDENCE: Case reports, level V.

Combined ACL-posterolateral corner injury in a skeletally immature athlete.

Combined injury to the anterior cruciate ligament (ACL) and posterolateral structures of the knee is a rare yet increasingly recognized clinical entity. In children or adolescents with open growth plates, this injury pattern is considered to be even more rare than in adults. Because knee ligaments are felt to be stronger than the adjacent physeal plates, the energy of pathologic translational and rotatory stress commonly results in fracture or avulsion injuries rather than ligamentous injury. The appropriate treatment for either injury remains controversial in the skeletally immature patient, with no previously reported case of this combined injury pattern in a patient with open physes. We present a case of a 12-year-old boy who sustained an ACL-posterolateral corner injury while playing football, and subsequently underwent acute repair of the posterolateral structures with a plan to perform ACL reconstruction at a later date.

Presentation and Surgical Management of Multiple Ligament Knee Injuries: A Multicenter Study from the Surgical Timing and Rehabilitation (STaR) Trial for MLKIs Network.

BACKGROUND: Multiple ligament knee injuries (MLKIs) represent a spectrum of injury patterns that are often associated with concomitant musculoskeletal and neurovascular injuries, complex treatment, and postoperative complications. However, there has not been high-level evidence describing the presentation and treatment of MLKIs. The purpose of this multicenter retrospective study was to describe characteristics of MLKIs, their management, and related complications using a pathoanatomic MLKI classification system based on the Schenck Knee Dislocation classification system. METHODS: This review identified and analyzed MLKIs that occurred between 2011 and 2015. Cases with an MLKI were included in this study if there was a complete tear of ≥2 ligaments and at least 1 ligament was repaired or reconstructed. Cases in which a ligament was deemed clinically incompetent due to a partial ligament tear and required surgical repair or reconstruction were considered equivalent to grade-III tears for inclusion and classification. Demographic information, the mechanism of injury, times from injury to presentation to an orthopaedic surgeon and to surgery, the ligament injury pattern, associated injuries, surgical procedures, and complications were captured. Data were analyzed descriptively. RESULTS: A total of 773 individuals from 14 centers who underwent surgery for an MLKI were reviewed. The mean age of the individuals was 30.5 ± 12.7 years, and 74.2% were male. The most common mechanism involved sports (43.2%). The median time from injury to presentation to the orthopaedic surgeon was 11 days (interquartile range [IQR], 3 to 48 days), and the time to initial ligament surgery was 64 days (IQR, 23 to 190 days). While the most common injury patterns were an anterior cruciate ligament tear combined with either a medial-sided (MLK 1-AM, 20.7%) or lateral-sided (MLK 1-AL, 23.2%) injury, one-third (34.7%) were bicruciate injuries. Associated injuries most often involved menisci (55.6%), nerves (18.5%) and tendons (15.6%). The method of surgical intervention (repair versus reconstruction), external fixator use, and staging of procedures varied by MLKI classification. Loss of motion (11.4%) was the most common postoperative complication. CONCLUSIONS: A better understanding of the clinical characteristics and management of the various MLKI patterns can be used to support clinical decision-making and individualized treatment of these complex injuries, and may ultimately lead to enhanced outcomes and reduced associated risks. LEVEL OF EVIDENCE: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Meniscal and Articular Cartilage Predictors of Outcome After Revision ACL Reconstruction: A 6-Year Follow-up Cohort Study.

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.

Medial meniscus tear morphology and chondral degeneration of the knee: is there a relationship?

PURPOSE: The purpose of this study was to examine the association of medial meniscus tear morphology with the pathogenesis of articular cartilage degeneration. METHODS: From May 2006 to December 2007, we prospectively evaluated 103 patients diagnosed with an isolated medial meniscus tear. Meniscus tear morphology and location, cartilage degeneration according to the Noyes score, and covariates including age, body mass index, gender, and injury date were documented. The relationship between severity of articular cartilage degeneration and meniscus tear morphology was analyzed by analysis of variance. Regression analysis was used to analyze predictors of severity of cartilage lesions. RESULTS: Analysis of variance showed significant differences in the severity of articular cartilage lesions based on medial meniscus tear morphology (P < .05). Compared with bucket-handle/vertical tears, root and radial/flap tears were associated with significantly greater degeneration on the medial femoral condyle; root and complex tears were associated with significantly greater degeneration on the medial tibial plateau; and radial/flap tears were associated with significantly greater degeneration on the lateral tibial plateau. Age and gender were significant predictors of the Noyes medial-compartment score, and age, body mass index, and meniscus tear morphology were significant predictors of the Noyes lateral-compartment score. CONCLUSIONS: Meniscus tears with increasing disruption of the circumferential meniscal fibers were significantly associated with cartilage lesions of increasing severity in both the medial and lateral compartments of the knee. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Bone-patellar tendon-bone autograft versus hamstring autograft anterior cruciate ligament reconstruction in the young athlete: a retrospective matched analysis with 2-10 year follow-up.

PURPOSE: The aim of this study was to examine clinical and patient-reported outcomes as well as return to sport in athletes younger than 25 following ACL reconstruction with either bone-patellar tendon-bone (BTB) or hamstring (HS) autografts using a matched-pairs case-control experimental design. METHODS: Twenty-three matched pairs were obtained based on gender (57% women), age (18 ± 3 years BTB vs. 18 ± 3 HS), and length of follow-up (5 ± 2 years BTB vs. 4 ± 2 HS). Patients reported participating in very strenuous (soccer, basketball, etc.) or strenuous (skiing, tennis, etc.) sporting activity 4-7 times/week prior to their knee injury. Patient-reported outcomes included return to play data, the IKDC, SAS, ADLS, and SF-36 forms. Clinical outcomes included knee range of motion, laxity, and hop/jump testing. RESULTS: The majority of patients in both groups were able to participate in very strenuous or strenuous sporting activity 4-7 times per week following surgery [17 (74%) BTB vs. 16 (70%) HS]. However, only 13 (57%) of the BTB subjects and 10 (44%) of the HS patients were able to return to pre-injury activity levels (P = n.s.). HS patients showed higher ADLS (P < 0.01) and SAS (P < 0.01) scores, better restoration of extension (P < 0.05), and less radiographic evidence of osteoarthritis (P < 0.05). CONCLUSIONS: Hamstring and bone-patellar tendon-bone autografts allow approximately 70% of young athletes to return to some degree of strenuous or very strenuous sporting activity, while only approximately half of patients were able to return to their pre-injury sporting activity level. Hamstring grafts lead to better preservation of extension, higher patient-reported outcome scores, and less radiographic evidence of osteoarthritis. LEVEL OF EVIDENCE: Therapeutic (case-control study) Level III.

Inclusion of open injuries in an updated Schenck classification of knee dislocations based on a global Delphi consensus study.

OBJECTIVES: Knee dislocations (KDs) are complex injuries defined as incongruity of the tibiofemoral joint, which leads to tears of two or more of the main stabilising knee ligaments, and they are often associated with damage to surrounding soft tissue or neurovascular structures. A classification system for these injuries should be simple and reproducible and allow communication among surgeons for surgical planning and outcome prediction. The aim of this study was to formulate a list of factors, prioritised by high-volume knee surgeons, that should be included in a KD classification system. METHODS: A global panel of orthopaedic knee surgery specialists participated in a Delphi process. The first survey employed 91 orthopaedic surgeons to generate a list of patient- and system-specific factors that should be included in a KD classification system that may affect surgical planning and outcomes. This list was subsequently prioritised by 27 identified experts (mean 15.3 years of experience) from Brazil (n = 9), USA (n = 6), South Africa (n = 4), India (n = 4), China (n = 2), and the United Kingdom (n = 2). The items were analysed to find factors that had at least 70% consensus for inclusion in a classification system. RESULTS: Of the 12 factors identified, four (33%) achieved at least 70% consensus for inclusion in a classification system. The factors deemed critical for inclusion in a classification system included vascular injuries (89%), common peroneal nerve injuries (78%), number of torn ligaments (78%), and open injuries (70%). CONCLUSION: Consensus for inclusion of various factors in a KD classification system was not easily achieved. The wide geographic distribution of participants provides diverse insight and makes the results of the study globally applicable. The most important factors to include in a classification system as determined by the Delphi technique were vascular injuries, common peroneal nerve injuries, number of torn ligaments, and open injuries. To date, the Schenck anatomic classification system most accurately identifies these patient variables with the addition of open injury classification. The authors propose to update the Schenck classification system with the inclusion of open injuries as an additional modifier, although this is only a small step in updating the classification, and further studies should evaluate the inclusion of more advanced imaging modalities. Future research should focus on integrating these factors into useful existing classification systems that are predictive of surgical treatment and patient outcomes.

Is It Time to Create Training Pathways Allowing Earlier Subspecialization within the "House of Orthopaedics"?: AOA Critical Issues.

ABSTRACT: The ability to train an orthopaedic resident in all aspects of orthopaedics in 5 years has become increasingly difficult due to the growth in knowledge and techniques, work-hour restrictions, and reduced resident autonomy. It has become nearly universal for our residents to complete at least 1 subspecialty fellowship prior to entering practice. In some subspecialties, the skills necessary to practice competently have become difficult to master. Simply adding to the current length of training may not address these issues effectively and would add to the economic cost of residency training. Novel training pathways that allow residents to focus earlier and in greater depth on their intended subspecialty while maintaining general orthopaedic competencies can be created without lengthening training. It is time to initiate discussions about these possibilities.

Returning to Activity After Anterior Cruciate Ligament Revision Surgery: An Analysis of the Multicenter Anterior Cruciate Ligament Revision Study (MARS) Cohort at 2 Years Postoperative.

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.

Descriptive Characteristics and Outcomes of Patients Undergoing Revision Anterior Cruciate Ligament Reconstruction With and Without Tunnel Bone Grafting.

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.

Multiple Ligament Knee Injuries: Does the Knee Dislocation Classification Predict the Type of Surgical Management?

This study aims to evaluate relationships among multiple ligament knee injury (MLKI) patterns as classified according to the knee dislocation (KD) classification and the types of surgical management pursued. We hypothesized that the KD classification would not be predictive of the types of surgical management, and that categorizing injuries according to additional injury features such as structure, chronicity, grade, and topographic location would be predictive of the types of surgical management. This is a Retrospective cohort study. This study was conducted at a level I trauma center with a 150-mile coverage radius. Query of our billing database was performed using combinations of 43 billing codes (International Classification of Diseases [ICD] 9, ICD-10, and Current Procedural Terminology) to identify patients from 2011 to 2015 who underwent operative management for MLKIs. There were operative or nonoperative treatment for individual ligamentous injuries, repair, or reconstruction of individual ligamentous injuries, and staging or nonstaging or nonstaging of each surgical procedure. The main outcome was the nature and timing of clinical management for specific ligamentous injury patterns. In total, 287 patients were included in this study; there were 199 males (69.3%), the mean age was 30.2 years (SD: 14.0), and the mean BMI was 28.8 kg/m2 (SD: 7.4). There were 212 injuries (73.9%) categorized as either KD-I or KD-V. The KD classification alone was not predictive of surgery timing, staging, or any type of intervention for any injured ligament (p > 0.05). Recategorization of injury patterns according to structure, chronicity, grade, and location revealed the following: partial non-ACL injuries were more frequently repaired primarily (p < 0.001), distal medial-sided injuries were more frequently treated operatively than proximal medial-sided injuries (odds ratio [OR] = 24.7; p <0.0001), and staging was more frequent for combined PCL-lateral injuries (OR = 1.3; p = 0.003) and nonavulsive fractures (OR = 1.2; p = 0.0009). The KD classification in isolation was not predictive of any surgical management strategy. Surgical management was predictable when specifying the grade and topographic location of each ligamentous injury. This is a Level IV, retrospective cohort study.

Association Between Graft Choice and 6-Year Outcomes of Revision Anterior Cruciate Ligament Reconstruction in the MARS Cohort.

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.

Rate of infection following revision anterior cruciate ligament reconstruction and associated patient- and surgeon-dependent risk factors: Retrospective results from MOON and MARS data collected from 2002 to 2011.

Infection is a rare occurrence after revision anterior cruciate ligament reconstruction (rACLR). Because of the low rates of infection, it has been difficult to identify risk factors for infection in this patient population. The purpose of this study was to report the rate of infection following rACLR and assess whether infection is associated with patient- and surgeon-dependent risk factors. We reviewed two large prospective cohorts to identify patients with postoperative infections following rACLR. Age, sex, body mass index (BMI), smoking status, history of diabetes, and graft choice were recorded for each patient. The association of these factors with postoperative infection following rACLR was assessed. There were 1423 rACLR cases in the combined cohort, with 9 (0.6%) reporting postoperative infections. Allografts had a higher risk of infection than autografts (odds ratio, 6.8; 95% CI, 0.9-54.5; p = .045). Diabetes (odds ratio, 28.6; 95% CI, 5.5-149.9; p = .004) was a risk factor for infection. Patient age, sex, BMI, and smoking status were not associated with risk of infection after rACLR.

Patellar tendon anterior cruciate ligament reconstruction in the high-demand patient: evaluation of autograft versus allograft reconstruction.

PURPOSE: This study sought to compare patient-reported and objective outcomes in high-demand patients after anterior cruciate ligament reconstruction with either patellar tendon allograft or autograft by use of a matched-pairs case-control experimental design. METHODS: Nineteen matched pairs were obtained based on gender (36.8% female patients), age (27.9 +/- 8.1 years in autograft group v 28.1 +/- 9.1 years in allograft group), and length of follow-up (9.1 +/- 2.7 years in autograft group v 10.3 +/- 2.6 years in allograft group). All patients reported participating in very strenuous (soccer, basketball, and so on) or strenuous (skiing, tennis, and so on) sporting activity 4 to 7 times per week before their knee injury. Patient-reported outcomes included the International Knee Documentation Committee Subjective Knee Form, Activities of Daily Living and Sports Activity Scales of the Knee Outcome Survey, and Short Form 36. Clinical evaluation included knee range of motion, laxity, and functional strength. RESULTS: There were no statistically significant differences in gender, age, or body mass index. There was a slight difference in length of follow-up (P < .05). The groups showed no statistically significant differences in any of the patient-reported or objective outcome measures. More autograft patients reported that they were able to perform very strenuous activity without the sense of instability (14 v 7), but this difference only approached statistical significance (P < .07). Twelve autograft patients were able to return to preinjury levels of sporting activity compared with ten allograft patients. Sixteen autograft patients and twelve allograft patients were able to participate in strenuous or very strenuous sporting activity at follow-up. Both differences were not statistically significant. CONCLUSIONS: Autograft and fresh-frozen allograft patellar tendon anterior cruciate ligament reconstruction exhibit similar patient-reported and objective outcomes in high-demand individuals at 3 to 14 years' follow-up. LEVEL OF EVIDENCE: Level III, therapeutic case-control study.