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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.

Objective Aim of this systematic review was to describe all classification systems for knee osteochondritis dissecans (OCD) lesions, evaluating their accuracy and reliability, as well as their use in the literature on knee OCD. Design A systematic review of the literature was performed in July 2021 on PubMed, WebOfScience, and Cochrane Collaboration (library) to describe all published classification systems for knee OCD lesions and quantify the use of these classifications in the literature. Results Out of 1,664 records, 30 studies on 33 OCD classifications systems were identified, describing 11 radiographic, 13 MRI, and 9 arthroscopic classifications. The search included 193 clinical studies applying at least one OCD classification, for a total of 7,299 knee OCD cases. Radiographic classifications were applied to 35.8%, MRI to 35.2%, and arthroscopic classifications to 64.2% of the included studies. Among these, in the last two decades, the International Cartilage Repair Society’s (ICRS) arthroscopic classification was the most described approach in studies on knee OCD. Overall, there is a lack of data on accuracy and reliability of the available systems. Conclusions Several classifications are available, with ICRS being the most used system over the time period studied. Arthroscopy allows to confirm lesion stability, but noninvasive imaging approaches are the first line to guide patient management. Among these, radiographic classifications are still widely used, despite being partially superseded by MRI, because of its capability to detect the earliest disease stages and to distinguish stable from unstable lesions, and thus to define the most suitable conservative or surgical approach to manage patients affected by knee OCD. Level of evidence: Systematic review, level IV.

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: 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.

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 post-operative infections. Allografts had a higher risk of infection than autografts (odds ratio=6.8; 95% CI: 0.9-54.5; p=0.045). Diabetes (odds ratio=28.6; 95% CI: 5.5-149.9; p=0.004) was a risk factor for infection. Patient age, sex, BMI and smoking status were not associated with risk of infection after rACLR. STATEMENT OF CLINICAL SIGNIFICANCE: While there is a low rate of infection following rACLR, use of allograft and comorbidity with diabetes are associated with a higher risk of infection following this surgery.

Objective Cartilage repair strategies have seen improvement in recent years, especially with the use of scaffolds that serve as a template for cartilage formation. However, current fixation strategies are inconsistent with regards to retention, may be technically challenging, or may damage adjacent tissues or the implant itself. Therefore, the goal of this study was to evaluate the retention and repair potential of cartilage scaffolds fixed with an easy-to-implement bioresorbable pin. Design Electrospun hyaluronic acid scaffolds were implanted into trochlear groove defects in 3 juvenile and 3 adult pigs to evaluate short-term retention (2 weeks; pin fixation vs. press-fit and fibrin fixation) and long-term repair (8 months; scaffold vs. microfracture), respectively. Results For the retention study, press-fit and fibrin fixation resulted in short-term scaffold dislodgment ( n = 2 each), whereas pin fixation retained all scaffolds that were implanted ( n = 6). Pin fixation did not cause any damage to the opposing patellar surface, and only minor changes in the subchondral bone were observed. For long-term repair, no differences were observed between microfracture and scaffold groups, in terms of second-look arthroscopy and indentation testing. On closer visualization with micro computed tomography and histology, a high degree of variability was observed between animals with regard to subchondral bone changes and cartilage repair quality, yet each Scaffold repair displayed similar properties to its matched microfracture control. Conclusions In this study, pin fixation did not cause adverse events in either the short- or the long-term relative to controls, indicating that pin fixation successfully retained scaffolds within defects without inhibiting repair.

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

Background:An unsalvageable osteochondritis dissecans (OCD) fragment has been defined as one that cannot be saved. Unsalvageable OCD lesions have been treated with various techniques, including fragment excision, microfracture, osteochondral autograft transfer, fresh osteochondral allograft transplantation, and autologous chondrocyte implantation (ACI).Hypothesis:Patients who underwent ACI as treatment for unsalvageable OCD more than 10 years ago would maintain satisfactory patient-oriented outcome measures and have a low need for additional open surgery, especially arthroplasty.Study Design:Case series; Level of evidence, 4.Methods:All Swedish and Norwegian patients (59 patients with 67 OCD lesions) who underwent ACI for OCD under the direction of the senior author between 1990 and 2005 were identified through manual chart review. Features of the patient, OCD lesion, and surgery were extracted from the medical record and intraoperative photographs. Patients were sent questionnaires to assess the Knee injury and Osteoarthritis Outcome Score, Tegner-Wallgren activity score, and Lysholm score. In addition, patients were asked whether they had to undergo further surgery, including knee replacement, of the knee that underwent ACI. They were asked whether they would have the surgery again if in the same situation.Results:A total of 55 patients (93%) with 61 OCD lesions (91%) responded. The median follow-up duration was 19 years (range, 10-26 years) and the median age at follow-up was 43 years (range, 28-69 years). Subsequent arthroscopy was performed in the majority of cases, although many of these were scheduled “second looks” as part of a study. With respect to other subsequent surgery, 12 knees (20%) underwent any additional open surgery, but only 2 knees (3%) underwent arthroplasty. Eight knees (13%) underwent revision ACI. Most patients reached their preinjury activity level (62%) and would undergo ACI again if in the same situation (85%). If failure is defined as revision of the graft or conversion to arthroplasty, then survivorship after ACI for OCD in the current study would be 87% at 10 years, 85% at 15 years, and 82% at 20 years.Conclusion:ACI for OCD provides a durable treatment option. At a median follow-up of 19 years, there was a very low (~3%) conversion to total knee arthroplasty.

Background: Matrix-induced chondrogenesis (MIC) is a promising treatment option for critical-size cartilage lesions of the knee; however, there exists substantial heterogeneity in the choice of acellular scaffold matrix for MIC cartilage repairs. Hypothesis: The choice of acellular matrix will not affect patient outcomes after MIC cartilage repair procedures, and the addition of concentrated bone marrow aspirate (cBMA) will improve short-term patient outcomes regardless of matrix choice. Study Design: Meta-analysis; Level of evidence, 4. Methods: Studies were stratified by matrix type: multilayered, single layered, and gel based. Continuous outcomes were analyzed with pairwise meta-analysis using the inverse variance model with random effects applied. Binary outcomes were analyzed as pooled proportions in a single-arm fashion; after which, reconstruction of relative risks (RRs) with confidence intervals was performed using the Katz logarithmic method. Results: A total of 876 patients were included: 469 received multilayered bioscaffolds; 238, gel-based scaffolds; and 169, single-layered scaffolds. The mean age of patients was 36.2 years (95% CI, 33.9 to 38.4), while the mean lesion size was 3.91 cm2 (95% CI, 3.40 to 4.42). The weighted mean follow-up was 23.8 months (95% CI, 20.1 to 27.6). Multilayered bioscaffolds were most effective at improving visual analog scale scores ( P = .03; weighted mean difference [WMD], −4.44 [95% CI, −4.83 to −4.06]; P < .001). There were significantly lower risks of incomplete defect filling for gel-based scaffolds when compared with multilayered scaffolds (RR, 0.78 [95% CI, 0.69 to 0.88]; P < .001) and single-layered scaffolds (RR, 0.58 [95% CI, 0.41 to 0.81]; P = .001). Augmentation with cBMA further improved clinical scores across all scaffolds, with significant improvements in Tegner score ( P = .02), while decreasing incomplete defect filling rates as well. There was significantly greater improvement in visual analog scale scores ( P = .01) for single-layered scaffolds with cBMA augmentation (WMD, −4.88 [95% CI, −5.38 to −4.37]; P < .001) as compared with single-layered scaffolds without cBMA augmentation (WMD, −4.08 [95% CI, −4.46 to −3.71]; P < .001). All significant improvements were below their respective minimum clinically important differences. Conclusion: While cartilage repair with acellular scaffolds provides significant improvements in pain and function for patients, there is insufficient clinical evidence to suggest which scaffold material is the most superior in influencing such improvements. The enhancement of cartilage repair procedures with cBMA may provide further functional improvements and improve defect filling; however, more long-term evidence is required to evaluate the effects.

Background: Osteochondritis dissecans (OCD) occurs most commonly in the knees of young individuals. This condition is known to cause pain and discomfort in the knee and can lead to disability and early knee osteoarthritis. The cause is not well understood, and treatment plans are not well delineated. The Research in Osteochondritis Dissecans of the Knee (ROCK) group established a multicenter, prospective cohort to better understand this disease. Purpose: To provide a baseline report of the ROCK multicenter prospective cohort and present a descriptive analysis of baseline data for patient characteristics, lesion characteristics, and clinical findings of the first 1000 cases enrolled into the prospective cohort. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients were recruited from centers throughout the United States. Baseline data were obtained for patient characteristics, sports participation, patient-reported measures of functional capabilities and limitations, physical examination, diagnostic imaging results, and initial treatment plan. Descriptive statistics were completed for all outcomes of interest. Results: As of November 2020, a total of 27 orthopaedic surgeons from 17 institutions had enrolled 1004 knees with OCD, representing 903 patients (68.9% males; median age, 13.1 years; range, 6.3-25.4 years), into the prospective cohort. Lesions were located on the medial femoral condyle (66.2%), lateral femoral condyle (18.1%), trochlea (9.5%), patella (6.0%), and tibial plateau (0.2%). Most cases involved multisport athletes (68.1%), with the most common primary sport being basketball for males (27.3% of cases) and soccer for females (27.6% of cases). The median Pediatric International Knee Documentation Committee (Pedi-IKCD) score was 59.9 (IQR, 45.6-73.9), and the median Pediatric Functional Activity Brief Scale (Pedi-FABS) score was 21.0 (IQR, 5.0-28.0). Initial treatments were surgical intervention (55.4%) and activity restriction (44.0%). When surgery was performed, surgeons deemed the lesion to be stable at intraoperative assessment in 48.1% of cases. Conclusion: The multicenter ROCK group has been able to enroll the largest knee OCD cohort to date. This information is being used to further understand the pathology of OCD, including its cause, associated comorbidities, and initial presentation and symptoms. The cohort having been established is now being followed longitudinally to better define and elucidate the best treatment algorithms based on these presenting signs and symptoms.

Chondral and osteochondral repair strategies are limited by adverse bony changes that occur after injury. Bone resorption can cause entire scaffolds, engineered tissues, or even endogenous repair tissues to subside below the cartilage surface. To address this translational issue, we fabricated poly(D,L-lactide-co-glycolide) (PLGA) microcapsules containing the pro-osteogenic agents triiodothyronine and ß-glycerophosphate, and delivered these microcapsules in a large animal model of osteochondral injury to preserve bone structure. We demonstrate that developed microcapsules rupturedin vitrounder increasing mechanical loads, and readily sink within a liquid solution, allowing for gravity-based positioning onto the osteochondral surface. In a large animal, these mechano-active microcapsules (MAMCs) were assessed through two different delivery strategies. Intra-articular injection of control MAMCs enabled fluorescent quantification of MAMC rupture and cargo release in a synovial joint setting over time in vivo. This joint-wide injection also confirmed that the MAMCs do not elicit an inflammatory response. In the contralateral hindlimbs, chondral defects were created, MAMCs were locally administered, and nanofracture (Nfx), a clinically utilized method to promote cartilage repair, was performed. The NFx holes enabled marrow-derived stromal cells to enter the defect area and served as repeatable bone injury sites to monitor over time. Animals were evaluated 1 and 2 weeks after injection and surgery. Analysis of injected MAMCs showed that bioactive cargo was released in a controlled fashion over 2 weeks. A bone fluorochrome label injected at the time of surgery displayed maintenance of mineral labeling in the therapeutic group, but resorption in both control groups. Alkaline phosphatase (AP) staining at the osteochondral interface revealed higher AP activity in defects treated with therapeutic MAMCs. Overall, this study establishes a new micro-fluidically generated delivery platform that releases therapeutic factors in an articulating joint, and reduces this to practice in the delivery of therapeutics that preserve bone structure after osteochondral injury.

Background: The most common presentation of knee osteochondritis dissecans (OCD) is a stable lesion on the lateral aspect of the medial femoral condyle (MFC) in an adolescent or pre-adolescent athlete. Standard of care for conservative treatment, include activity modification and weight bearing protection. Failed conservative management often leads arthroscopy and drilling of the lesion. Two different primary drilling techniques have been utilized, but no prospective studies have compared their relative effectiveness. Hypothesis/Purpose: The study hypothesis was that trans-articular (TAD) and retro-articular drilling (RAD) would demonstrate similar rates of healing, times to return to sports, and patient-reported outcome scores (PROs). Methods: Skeletally immature (n=113) patients presenting with radiograph indicated stable OCD of the MFC who did not demonstrate healing despite a minimum of 3 months of non-operative treatment were prospectively enrolled and randomized to TAD or RAD, for which 17 surgeon-investigators (at 14 centers, representing all major regions in the U.S.). Serial radiographs were obtained every 6 weeks to assess healing, and PROs were obtained at 6 months, 12 months, and 24 months. Twelve patients were due to lesion instability detected at the time of surgery, Results: Ninety-one study subjects were included, consisting of 51 TAD and 40 RAD patients, with the two groups being of similar age (12.6 years vs. 11.9 years), sex distribution (45% vs. 27% female, p=0.081), and 2-year PRO response rate (both 90%). No significant difference between TAD and RAD was detected in follow-up Pedi-IKDC, Lysholm, Marx knee activity score, or KOOS QOL scores (Table 1). Revision/additional OCD surgery occurred in 10% of patients in RAD and 4% in TAD. 71% of TAD patients reached a ‘healed’ status at a mean of 1.15 years, compared with 58% RAD patients at a mean of 1.06 years. Conclusion: While both primary forms of OCD drilling (TAD and RAD) showed consistent post-operative healing, achieving a completely ‘healed’ status was often a more prolonged process, taking approximately 1 year, despite clinical improvement being achieved much sooner. While PROs were similar between drilling techniques, revision surgery rates were more than twice as common with RAD compared with TAD but the overall risk was low and the Absolute Risk was only 6%. [Table: see text]

Objectives: The most common presentation of knee osteochondritis dissecans (OCD) is a stable lesion on the lateral aspect of the medial femoral condyle (MFC) in an adolescent or pre-adolescent athlete. The standard of care for primary treatment is non-operative, and includes rest/activity modification and often weight bearing protection or bracing. Failed conservative management often leads arthroscopy and drilling of the lesion. Two different primary drilling techniques have been utilized, but no prospective studies have compared their relative effectiveness. The study hypothesis was that retro-articular drilling (RAD), the slightly newer technique, would not be inferior to trans-articular (TAD), with regard to rate of healing, time to return to sports (RTS), and patient-reported outcome scores (PROs). Methods: Skeletally immature (n=113) patients presenting with MRI-confirmed stable OCD of the MFC who did not demonstrate substantial healing after a minimum of 3 months of non-operative treatment were prospectively enrolled by one of seventeen surgeon-investigators (at 14 centers, representing all major geographic regions in the U.S.) and randomized to TAD or RAD. Post-operatively, serial radiographs were obtained every 6 weeks to assess healing, and PROs were obtained at 6 months, 12 months, and 24 months. Twelve patients were closed out at time of surgery due to lesion instability detected during arthroscopy. Power analysis determined that in order to detect a difference in 2-year IKDC score between RA and TA groups with 80% power, sample sizes of 37 subjects per group would be required if the true standard deviation were 15. This analysis was based on conducting an independent samples Student’s t-test with alpha set to 5%. Results: Ninety-one study subjects were included, consisting of 51 TAD and 40 RAD patients, respectively, with the two groups being similar in age (12.6 years vs. 11.9 years), sex distribution (45% vs. 27% female, p=0.081), and 2-year PRO response rate (both 90%). No significant differences between TAD and RAD were detected in follow-up Pedi-IKDC, Lysholm, Marx knee activity score, or KOOS QOL scores (Table 1). Revision/additional OCD surgery occurred in 10% of patients in RAD and 4% in TAD (p=0.40). 73% of TAD patients reached a ‘healed’ status at a mean of 1.15 years, compared with 60% RAD patients at a mean of 1.21 years. Conclusions: While both primary forms of OCD drilling (TAD and RAD) showed consistent post-operative healing, achieving a completely ‘healed’ status was often a more prolonged process, taking approximately 1 year, despite clinical improvement and RTS being achieved much sooner. PROs were similar between drilling techniques. Significantly higher powered studies are needed to better elucidate the greater revision surgery rates in RAD compared with TAD, but overall risk is low and absolute risk only 6%. The current data support either drilling technique, which may be technically simpler, without the need for fluoroscopy, with TAD, and may be more protective of the chondral articular surface with RAD.

BackgroundFatty infiltration (FI) is one of the most important prognostic factors for outcomes after rotator cuff surgery. Established risk factors include advancing age, larger tear size, and increased tear chronicity. A growing body of evidence suggests that sex and obesity are associated with FI; however, data are limited.MethodsWe recruited 2 well-characterized multicenter cohorts of patients with rotator cuff tears (Multicenter Orthopaedic Outcomes Network [MOON] cohort [n=80] and Rotator Cuff Outcomes Workgroup [ROW] cohort [n=158]). We used multivariable logistic regression to evaluate the relationship between body mass index (BMI) and the presence of FI while adjusting for the participant's age at magnetic resonance imaging, sex, and duration of shoulder symptoms, as well as the cross-sectional area of the tear. We analyzed the 2 cohorts separately and performed a meta-analysis to combine estimates.ResultsA total of 27 patients (33.8%) in the Multicenter Orthopaedic Outcomes Network (MOON) cohort and 57 patients (36.1%) in the Rotator Cuff Outcomes Workgroup (ROW) cohort had FI. When BMI < 25 kg/m2 was used as the reference category, being overweight was associated with a 2.37-fold (95% confidence interval [CI], 0.77-7.29) increased odds of FI and being obese was associated with a 3.28-fold (95% CI, 1.16-9.25) increased odds of FI. Women were 4.9 times (95% CI, 2.06-11.69) as likely to have FI as men.ConclusionsAmong patients with rotator cuff tears, obese patients had a substantially higher likelihood of FI. Further research is needed to assess whether modifying BMI can alter FI in patients with rotator cuff tears. This may have significant clinical implications for presurgical surgical management of rotator cuff tears. Sex was also significantly associated with FI, with women having higher odds of FI than men. Higher odds of FI in female patients may also explain previously reported early suboptimal outcomes of rotator cuff surgery and higher pain levels in female patients as compared with male patients.

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.

Revision anterior cruciate ligament (ACL) reconstruction has been documented to have worse outcomes than primary ACL reconstruction. The reasons remain varied and not completely understood. METHODS: Patients undergoing revision ACL reconstruction were prospectively enrolled. Data collected included baseline demographics, surgical technique and pathological condition, prescribed rehabilitation instructions, and a series of validated patient-reported outcome instruments. Patients were followed for 2 years and asked to complete a set of outcome instruments identical to those completed at baseline. Subsequent surgical procedures on the ipsilateral knee were recorded. Regression analysis was used to control for age, sex, activity level, baseline outcome scores, and the above-mentioned rehabilitation-related variables in order to assess the factors affecting clinical outcomes 2 years after revision ACL reconstruction. RESULTS: A total of 843 patients met the inclusion criteria and were successfully enrolled, and 82% (695) were followed for 2 years. Two rehabilitation-related factors were found to influence outcome. First, patients who were prescribed an ACL brace for their return to sports had a significantly better Knee injury and Osteoarthritis Outcome Score (KOOS) for sports and recreational activities at 2 years (odds ratio [OR] =1.50, 95% confidence interval [CI] = 1.07 to 2.11; p = 0.019). Second, patients prescribed an ACL brace for the postoperative rehabilitation period were 2.3 times more likely to have subsequent surgery by 2 years (OR = 2.26, 95% CI = 1.11 to 4.60; p = 0.024). The odds of a graft rerupture were not affected by any type of brace wear. CONCLUSIONS: Rehabilitation-related factors that the physician can control at the time of an ACL reconstruction have the ability to influence clinical outcomes at 2 years. Weight-bearing and motion can be initiated immediately postoperatively. Bracing during the early postoperative period is not helpful. Use of a functional brace early in the postoperative period was associated with an increased risk of a reoperation. Use of a functional brace for a return to sports improved the KOOS on the sports/recreation subscale. LEVEL OF EVIDENCE: Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Chondral and osteochondral repair strategies are limited by adverse bony changes that occur after injury. Bone resorption can cause entire scaffolds, engineered tissues, or even endogenous repair tissues to subside below the cartilage surface. To address this translational issue, we fabricated thick-shelled poly(D,L-lactide-co-glycolide) microcapsules containing the pro-osteogenic agents triiodothyronine and β-glycerophosphate, and delivered these microcapsules in a large animal model of osteochondral injury to preserve bone structure. We demonstrate that the developed microcapsules ruptured in vitro under increasing mechanical loads, and readily sink within a liquid solution, enabling gravity-based patterning along the osteochondral surface. In a large animal, these mechanically-activated microcapsules (MAMCs) were assessed through two different delivery strategies. Intra-articular injection of control MAMCs enabled fluorescent quantification of MAMC rupture and cargo release in a synovial joint setting over time in vivo. This joint-wide injection also confirmed that the MAMCs do not elicit an inflammatory response. In the contralateral hindlimbs, chondral defects were created, MAMCs were patterned in situ, and nanofracture (Nfx), a clinically utilized method to promote cartilage repair, was performed. The Nfx holes enabled marrow-derived stromal cells to enter the defect area and served as repeatable bone injury sites to monitor over time. Animals were evaluated one and two weeks after injection and surgery. Analysis of injected MAMCs showed that bioactive cargo was released in a controlled fashion over two weeks. A bone fluorochrome label injected at the time of surgery displayed maintenance of mineral labeling in the therapeutic group, but resorption in both control groups. Alkaline phosphatase (AP) staining at the osteochondral interface revealed higher AP activity in defects treated with therapeutic MAMCs. Overall, this study develops a gravity-based approach to pattern bioactive factors along the osteochondral interface, and applies this novel biofabrication strategy to preserve bone structure after osteochondral injury.

Marrow stimulation, including subchondral drilling and microfracture, is the most commonly performed cartilage repair strategy, whereby the subchondral bone plate is perforated to release marrow-derived cells into a cartilage defect to initiate repair. Novel scaffolds and therapeutics are being designed to enhance and extend the positive short-term outcomes of this marrow stimulation. However, the translation of these newer treatments is hindered by bony abnormalities, including bone resorption, intralesional osteophytes, and bone cysts, that can arise after marrow stimulation. In this study, three different marrow stimulation approaches — microfracture, subchondral drilling, and needle-puncture – were evaluated in a translationally relevant large animal model, the Yucatan minipig. The objective of this study was to determine which method of marrow access (malleted awl, drilled Kirschner wire, or spring-loaded needle) best preserved the underlying subchondral bone. Fluorochrome labels were injected at the time of surgery and 2 weeks post-surgery to capture bone remodeling over the first 4 weeks. Comprehensive outcome measures included cartilage indentation testing, histological grading, microcomputed tomography, and fluorochrome imaging. Our findings indicated that needle-puncture devices best preserved the underlying subchondral bone relative to other marrow access approaches. This may relate to the degree of bony compaction occurring with marrow access, as the Kirschner wire approach, which consolidated bone most, induced the most significant bone damage with marrow stimulation. This study provides basic science evidence in support of updated marrow stimulation techniques for preclinical and clinical practice.

Since Franz Konig first described and coined the term osteochondritis dissecans (OCD), much has been learned. Currently, there is no conclusive agreement on the exact cause of OCD. Several etiological hypotheses have been suggested which include occult or repetitive microtrauma, inflammatory, and vascular abnormalities as well as the possibility of genetic predisposition. Understanding the behavior of OCD lesions is paramount to determining the most appropriate treatment. As such, the ROCK group has developed novel classification schemes for X-ray, MRI, and arthroscopy to help further characterize and categorize OCD lesions of the knee. These lesions have been categorized into two distinct groups representing mobile and immobile progeny fragments.

ObjectiveThe aim of this study was to evaluate levels of consensus in rehabilitation practices following MACI (autologous cultured chondrocytes on porcine collagen membrane) treatment based on the experience of an expert panel of U.S. orthopedic surgeons.DesignA list of 24 questions was devised based on the current MACI rehabilitation protocol, literature review, and discussion with orthopedic surgeons. Known areas of variability were used to establish 4 consensus domains, stratified on lesion location (tibiofemoral [TF] or patellofemoral [PF]), including weightbearing (WB), range of motion (ROM), return to work/daily activities of living, and return to sports. A 3-step Delphi technique was used to establish consensus.ResultsConsensus (>75% agreement) was achieved on all 4 consensus domains. Time to full WB was agreed as immediate (with bracing) for PF patients (dependent on concomitant procedures), and 7 to 9 weeks in TF patients. A progression for ROM was agreed that allowed patients to reach 90° by week 4, with subsequent progression as tolerated. The panel estimated that the time to full ROM would be 7 to 9 weeks on average. A range of time was established for release to activities of daily living, work, and sports, dependent on lesion and patient characteristics.ConclusionsGood consensus was established among a panel of U.S. surgeons for rehabilitation practices following MACI treatment of knee cartilage lesions. The consensus of experts can aid surgeons and patients in the expectations and rehabilitation process as MACI surgery becomes more prevalent in the United States.

Engineering complex tissues represents an extraordinary challenge and, to date, there have been few strategies developed that can easily recapitulate native-like cell and biofactor gradients in three-dimensional materials. This is true despite the fact that mimicry of these gradients may be essential for the functionality of engineered graft tissues. Here, a non-traditional magnetics-based approach is developed to predictably position naturally diamagnetic objects in 3D hydrogels. Rather than magnetizing the objects within the hydrogel, the magnetic susceptibility of the surrounding hydrogel precursor solution is enhanced. In this way, a range of diamagnetic objects (e.g. polystyrene beads, drug delivery microcapsules, and living cells) are patterned in response to a brief exposure to a magnetic field. Upon photo-crosslinking the hydrogel precursor, object positioning is maintained, and the magnetic contrast agent diffuses out of the hydrogel, supporting long-term construct viability. This approach is applied to engineer cartilage constructs with a depth-dependent cellularity mirroring that of native tissue. To the best of the knowledge, these are the first results showing that magnetically unaltered cells can be magneto-patterned in hydrogels and cultured to generate heterogeneous tissues. This work provides a foundation for the formation of opposing magnetic susceptibility-based gradients within a single continuous material.

Background: In December 2016, MACI (autologous cultured chondrocytes on porcine collagen membrane) received approval from the US Food and Drug Administration for the treatment of symptomatic articular cartilage defects of the knee with or without bone involvement in adults. Purpose: To describe the cartilage defects and patient characteristics for 1000 adult patients treated with MACI for knee cartilage repair in the United States. Study Design: Case series; Level of evidence, 4. Methods: Data collected by Vericel for adult patients treated for articular cartilage defects of the knee were reconciled and summarized. Data were collected for 1000 consecutive patients starting on July 1, 2017, when Carticel (the prior generation of autologous cultured chondrocytes) was no longer available. Patient names were removed for confidentiality, and patients were identified by MACI lot number and surgery date. Safety data were derived from the pharmacovigilance database. Patient demographics, cartilage defect characteristics, concomitant surgical procedures, and adverse events were summarized with descriptive statistics. Results: A total of 1000 adults and 1010 knee joints were implanted with MACI by 372 surgeons. The male (49.6%)-to-female (50.4%) ratio was evenly split, and the mean age was 34.0 years. The majority of patients (68.1%) had a single cartilage defect treated, and the mean treated defect size was 4.7 cm2. The mean total treated lesion size, including multiple defects, was 5.8 cm2. The patella was the most commonly treated joint surface (32.7%), followed by the medial femoral condyle (31.3%). Most patients (92.4%) had concomitant surgical procedures at the time of cartilage biopsy acquisition. The most common concomitant procedures at the time of biopsy procurement included cartilage debridement (83.7%) and meniscal resection (11.3%). The most common planned concomitant surgeries at the time of MACI implantation were anterior tibial tubercleplasty (7.8%) and reconstruction of dislocating patella (5.5%). Few patients (2.6%) had adverse events. Conclusion: Patient age and mean total MACI-treated defect size in the United States are similar to the findings of the pivotal European SUMMIT (Superiority of MACI Implant Versus Microfracture Treatment) trial and other studies from outside the United States. Treatment of multiple cartilage defects is more frequent in the United States than elsewhere.

Objectives: Determining bone age in skeletally immature patients is critical for proper management and surgical planning. Pennock et al. recently created and validated a bone age atlas using the ossification pattern of the knee on MRI in pediatric patients, obfuscating the need for a hand radiograph and its associated cost, radiation exposure, and clinical inefficiency. This aim of this study was to create and validate a shorthand method of bone age determination using knee MRI. Methods: We identified patients who underwent both knee MRI and hand bone age radiograph within a ninety-day period. From the findings of Pennock et al., a stepwise algorithm for predicting bone age on knee MRI was developed for males and females separately, in collaboration with a pediatric musculoskeletal radiologist. Six raters at varying levels of training used the algorithm to assign a bone age to each knee MRI. Intraclass correlation coefficient (ICC) was used to compare each rater’s predicted knee bone age to the Greulich and Pyle (G&P) hand bone age and validate the shorthand algorithm. Inter- (two-way random, absolute agreement) and intra-rater (two-way mixed, absolute agreement ) reliability were also calculated using ICC. Results: Thirty-eight patients (44.7% females) underwent a knee MRI at a mean age of 12.8 years (range 9.3-15.7). The mean time between hand bone age x-ray and knee MRI was 20.2 days (range 0-88). The inter-rater reliability for the application of our shorthand algorithm was 0.81 (95% CI: 0.72 – 0.88), indicating good inter-observer agreement. The shorthand algorithm was also shown to be a reliable predictor of hand bone age across level of training, as medical students (ICC 0.77, 95% CI 0.60-0.88), residents (ICC 0.80, 95% CI 0.65-0.89), and attending physicians (ICC 0.80, 95% CI 0.63-0.89) all achieved strong correlation between predicted knee bone age and G&P hand bone age. All respondents also demonstrated consistency, with intra-rater ICCs between 0.85-0.93. Conclusion: This shorthand algorithm is a consistent, reliable and valid way to determine skeletal maturity using knee MRI in patients aged 10 to 15 and can be utilized across different levels of orthopaedic and radiographic expertise. We believe this method is readily applicable in a clinical setting and may reduce the need for routine hand bone age radiographs. Figure 1. Table 1. Correlation between knee MRI bone age and hand radiograph bone age (G&P) for each rater, as determined using intraclass correlation coefficients (ICC). Note: Intra-rater reliability has not been competed for “Resident 2” at this time. Validity of MRI Knee Bone Age and Hand Bone Age Intra-Rater Reliability Rater ICC 95% CI ICC 95% CI Student 1 0.75 0.57-0.86 0.93 0.79-0.97 Student 2 0.73 0.53-0.86 0.93 0.87-0.97 Resident 1 0.73 0.54-0.85 0.85 0.73-0.92 Resident 2 0.78 0.60-0.88 - - Attending 1 0.74 0.54-0.85 0.86 0.70-0.93 Attending 2 0.80 0.63-0.89 0.86 0.72-0.93

Background: Imaging characteristics of osteochondritis dissecans (OCD) lesions quantified by magnetic resonance imaging (MRI) are often used to inform treatment and prognosis. However, the interrater reliability of clinician-driven MRI-based assessment of OCD lesions is not well documented. Purpose: To determine the interrater reliability of several historical and novel MRI-derived characteristics of OCD of the knee in children. Study Design: Cohort study (diagnosis); Level of evidence, 3 Methods: A total of 42 OCD lesions were evaluated by 10 fellowship-trained orthopaedic surgeons using 31 different MRI characteristics, characterizing lesion size and location, condylar size, cartilage status, the interface between parent and progeny bone, and features of both the parent and the progeny bone. Interrater reliability was determined via intraclass correlation coefficients (ICCs) with 2-way random modeling, Fleiss kappa, or Krippendorff alpha as appropriate for each variable. Results: Raters were reliable when the lesion was measured in the coronal plane (ICC, 0.77). Almost perfect agreement was achieved for condylar size (ICC, 0.93), substantial agreement for physeal patency (ICC, 0.79), and moderate agreement for joint effusion (ICC, 0.56) and cartilage status (ICC, 0.50). Overall, raters showed significant variability regarding interface characteristics (ICC, 0.25), progeny (ICC range, 0.03 to 0.62), and parent bone measurements and qualities (ICC range, –0.02 to 0.65), with reliability being moderate at best for these measurements. Conclusion: This multicenter study determined the interrater reliability of MRI characteristics of OCD lesions in children. Although several measurements provided acceptable reliability, many MRI features of OCD that inform treatment decisions were unreliable. Further work will be needed to refine the unreliable characteristics and to assess the ability of those reliable characteristics to predict clinical lesion instability and prognosis.

Background: Determining bone age in skeletally immature patients is critical for proper management and surgical planning. Pennock et al. recently created and validated a bone age atlas using the ossification pattern of the knee on MRI in pediatric patients, obfuscating the need for a hand radiograph and its associated cost, radiation exposure, and clinical inefficiency. Hypothesis/Purpose: We sought to validate and demonstrate reliability of a novel shorthand method of bone age determination using knee MRI across multiple levels of medical training. Methods: We identified patients who underwent knee MRI and hand bone age radiograph within a ninety-day period. In collaboration with a pediatric musculoskeletal radiologist, stepwise algorithms for predicting bone age on knee MRI were developed- one for males and one for females. Six raters at varying levels of training used the algorithm to assign a bone age for each patient. Intraclass correlation coefficient (ICC) was used to compare each rater’s predicted knee bone age to the Greulich and Pyle (G&P) hand bone age and validate the shorthand algorithm. Inter-rater reliability was also calculated using ICC. Results: Thirty-eight patients (44.7% female) underwent a knee MRI at a mean age of 12.8 years (range 9.3-15.7). The mean time between hand bone age x-ray and knee MRI was 20.2 days (range 0-88). The inter-rater reliability for the application of our shorthand algorithm was 0.81 (95% CI: 0.72 – 0.88), indicating good inter-observer agreement. The shorthand methos was shown to be a good predictor of G&P hand bone age, both for each individual rater (ICC range: 0.73 – 0.80) and the mean knee MRI bone age across all raters (ICC 0.81; 95% CI 0.65 – 0.90). It was also shown to be a consistent predictor of hand bone age across level of training, as medical students (ICC 0.77, 95% CI 0.60-0.88), residents (ICC 0.80, 95% CI 0.65-0.89), and attending physicians (ICC 0.80, 95% CI 0.63-0.89) all achieved strong correlation between predicted knee MRI bone age and G&P hand bone age. Conclusions: This novel shorthand algorithm is a reliable and valid way to determine skeletal maturity using knee MRI. It can be utilized clinically across different levels of radiographic and orthopaedic expertise and reduces the need for hand bone age radiographs and consequential radiation exposure in children. Figure 1. Shorthand Algorithm for Knee Bone Age Using MRI for Males Figure 2. Shorthand Algorithm for Knee Bone Age Using MRI for Females Table 1. Correlation between knee MRI bone age and hand radiograph bone age (G&P) for each rater, as determined using intraclass correlation coefficients (ICC). Rater ICC 95% CI Student 1 0.75 0.57 – 0.86 Student 2 0.73 0.53 – 0.86 Resident 1 0.73 0.54 – 0.85 Resident 2 0.78 0.60 – 0.88 Attending 1 0.74 0.54 – 0.85 Attending 2 0.80 0.63 – 0.89 Mean 0.83 0.68 – 0.91

The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these revised clinical practice guidelines is to review recent peer-reviewed literature and make recommendations related to meniscus and articular cartilage lesions. J Orthop Sports Phys Ther. 2018;48(2):A1-A50. doi:10.2519/jospt.2018.0301.

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 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: Bone-age determination remains a difficult process. An atlas for bone age has been created from knee-ossification patterns on magnetic resonance imaging (MRI), thereby avoiding the need for radiographs and associated costs, radiation exposure, and clinical inefficiency. Shorthand methods for bone age can be less time-consuming and require less extensive training as compared with conventional methods. Purpose: To create and validate a novel shorthand algorithm for bone age based on knee MRIs that could correlate with conventional hand bone age and demonstrate reliability across medical trainees. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Included in this study were adolescent patients who underwent both knee MRI and hand bone age radiographs within 90 days between 2009 and 2018. A stepwise algorithm for predicting bone age using knee MRI was developed separately for male and female patients, and 7 raters at varying levels of training used the algorithm to determine the bone age for each MRI. The shorthand algorithm was validated using Spearman rho ( rS) to correlate each rater’s predicted MRI bone age with the recorded Greulich and Pyle (G&P) hand bone age. Interrater and intrarater reliability were also calculated using intraclass correlation coefficients (ICCs). Results: A total of 38 patients (44.7% female) underwent imaging at a mean age of 12.8 years (range, 9.3-15.7 years). Shorthand knee MRI bone age scores were strongly correlated with G&P hand bone age ( rS = 0.83; P < .001). The shorthand algorithm was a valid predictor of G&P hand bone age regardless of level of training, as medical students ( rS = 0.75), residents ( rS = 0.81), and attending physicians ( rS = 0.84) performed similarly. The interrater reliability of our shorthand algorithm was 0.81 (95% CI, 0.73-0.88), indicating good to excellent interobserver agreement. Respondents also demonstrated consistency, with 6 of 7 raters demonstrating excellent intrarater reliability (median ICC, 0.86 [range, 0.68-0.96]). Conclusion: This shorthand algorithm is a consistent, reliable, and valid way to determine skeletal maturity using knee MRI in patients aged 9 to 16 years and can be utilized across different levels of orthopaedic and radiographic expertise. This method is readily applicable in a clinical setting and may reduce the need for routine hand bone age radiographs.

The goal of this paper is to review the current management and prevention of post-operative complications after anterior cruciate ligament (ACL) reconstruction. Trends in rehabilitation techniques will be presented, in addition to suggestions for interventions and expected milestones in ACL reconstruction recovery. ACL reconstruction protocols have evolved to more of a criterion-based progression rather than a tissue-healing time frame. Given the evolution of ACL surgical reconstruction techniques and rehabilitation protocols, the risk of post-operative complications can arise both early and late in the recovery process. This paper will discuss the role of preventative measures as it applies to the post-operative patient with ACL reconstruction. Short-term complications following ACL reconstruction include infection and deficits to knee motion and strength, whereas long-term complications include secondary ACL injury to either the involved or contralateral knee and lack of ability to return to high-level sports following this procedure. Future research should continue to address the multifactorial causes of secondary ACL injury and limited ability of patients to return to high level activities.

Background Cartilage lesions of the knee are difficult to treat. Lesion size is a critical factor in treatment algorithms, and the accurate, reproducible sizing of lesions is important. In this study, we evaluated the interrater and intrarater reliability of, and correlations in relation to, various arthroscopic sizing techniques. Methods Five lesions were created in each of 10 cadaveric knees (International Cartilage Repair Society grade 3C). Three orthopaedic surgeons used 4 techniques (visualization and use of a 3-mm probe, a simple metal ruler, and a sliding metallic ruler tool) to estimate lesion size. Repeated-measures data were analyzed using a mixed-effect linear model. The differences between observed and gold-standard (plastic mold) values were used as the response. Intraclass and interclass correlation coefficient (ICC) values for intrarater and interrater reliability were computed, as were overall correlation coefficients between measurements and gold standards. Results The mean lesion size was 2.37 cm (range, 0.36 to 6.02 cm). Rater, lesion location and size, and measurement method all affected the cartilage defect measurements. Surgeons underestimated lesion size, and measurements of larger lesions had a higher percentage of error compared with those of smaller lesions. When compared with plastic molds of lesions, 60.5% of surgeon measurements underestimated lesion size. Overall, the correlation between measurements and gold standards was strongest for the simple metal ruler method and weakest for the visualization method. Conclusions Several factors may influence arthroscopic estimation of cartilage lesion size: the lesion location, measurement tool, surgeon, and defect size itself. The intrarater and interrater reliability was moderate to good using a 3-mm probe, sliding metallic ruler tool, or simple metal ruler and was fair to moderate using visualization only. Clinical relevance There is a need for more accurate methods of determining the size of articular cartilage lesions.

The field of articular cartilage repair has made significant advances in recent decades; yet current therapies are generally not evaluated or tested, at the time of pivotal trial, in patients with a variety of common comorbidities. To that end, we systematically reviewed cartilage repair clinical trials to identify common exclusion criteria and reviewed the literature to identify emerging regenerative approaches that are poised to overcome these current exclusion criteria. The term “knee cartilage repair” was searched on clinicaltrials.gov. Of the 60 trials identified on initial search, 33 were further examined to extract exclusion criteria. Criteria excluded by more than half of the trials were identified in order to focus discussion on emerging regenerative strategies that might address these concerns. These criteria included age (55 years old), small defects (2), large defects (>8 cm2), multiple defect (>2 lesions), BMI >35, meniscectomy (>50%), bilateral knee pathology, ligamentous instability, arthritis, malalignment, prior repair, kissing lesions, neurologic disease of lower extremities, inflammation, infection, endocrine or metabolic disease, drug or alcohol abuse, pregnancy, and history of cancer. Finally, we describe emerging tissue engineering and regenerative approaches that might foster cartilage repair in these challenging environments. The identified criteria exclude a majority of the affected population from treatment, and thus greater focus must be placed on these emerging cartilage regeneration techniques to treat patients with the challenging “red knee”.

Cartilage injuries and subsequent tissue deterioration impact millions of patients. Since the regeneration of functional hyaline cartilage remains elusive, methods to stabilize the remaining tissue, and prevent further deterioration, would be of significant clinical utility and prolong joint function. Finite element modeling shows that fortification of the degenerate cartilage (Reinforcement) and reestablishment of a superficial zone (Sealing) are both required to restore fluid pressurization within the tissue and restrict fluid flow and matrix loss from the defect surface. Here, a hyaluronic acid (HA) hydrogel system is designed to both interdigitate with and promote the sealing of the degenerated cartilage. Interdigitating fortification restores both bulk and local pericellular tissue mechanics, reestablishing the homeostatic mechanotransduction of endogenous chondrocytes within the tissue. This HA therapy is further functionalized to present chemo mechanical cues that improve the attachment and direct the response of mesenchymal stem/stromal cells at the defect site, guiding localized extracellular matrix deposition to "seal" the defect. Together, these results support the therapeutic potential, across cell and tissue length scales, of an innovative hydrogel therapy for the treatment of damaged cartilage.

The importance of emotional and psychological factors in treatment of patients with rotator cuff disease has been recently emphasized. Our goal was to establish factors most predictive of poor emotional health in patients with full-thickness rotator cuff tears (FTRCTs).In 2007, we began to prospectively collect data on patients with symptomatic, atraumatic FTRCTs. All patients completed a questionnaire collecting data on demographics, symptom characteristics, comorbidities, willingness to undergo surgery, and patient-related outcomes (12-Item Short Form Health Survey, American Shoulder and Elbow Surgeons score, Western Ontario Rotator Cuff Index [WORC], Single Assessment Numeric Evaluation score, Shoulder Activity Scale). Physicians recorded physical examination and imaging data. To evaluate the predictors of lower WORC emotion scores, a linear multiple regression model was fit.Baseline data for 452 patients were used for analysis. In patients with symptomatic FTRCTs, the factors most predictive of worse WORC emotion scores were higher levels of pain (interquartile range odds ratio, -18.9; 95% confidence interval, -20.2 to -11.6; P .0001) and lower Single Assessment Numeric Evaluation scores (rating of percentage normal that patients perceive their shoulder to be; interquartile range odds ratio, 6.2; 95% confidence interval, 2.5-9.95; P = .0012). Higher education (P = .006) and unemployment status (P = .0025) were associated with higher WORC emotion scores.Education level, employment status, pain levels, and patient perception of percentage of shoulder normalcy were most predictive of emotional health in patients with FTRCTs. Structural data, such astendon tear size, were not. Those with poor emotional health may perceive their shoulder to be worse than others and experience more pain. This may allow us to better optimize patient outcomes with nonoperative and operative treatment of rotator cuff tears.