Surgical restabilization reduces the progression of post-traumatic osteoarthritis initiated by ACL rupture in mice.

OBJECTIVE: People who sustain joint injuries such as anterior cruciate ligament (ACL) rupture often develop post-traumatic osteoarthritis (PTOA). In human patients, ACL injuries are often treated with ACL reconstruction. However, it is still unclear how effective joint restabilization is for reducing the progression of PTOA. The goal of this study was to determine how surgical restabilization of a mouse knee joint following non-invasive ACL injury affects PTOA progression. DESIGN: In this study, 187 mice were subjected to non-invasive ACL injury or no injury. After injury, mice underwent restabilization surgery, sham surgery, or no surgery. Mice were then euthanized on day 14 or day 49 after injury/surgery. Functional analyses were performed at multiple time points to assess voluntary movement, gait, and pain. Knees were analyzed ex vivo with micro-computed tomography, RT-PCR, and whole-joint histology to assess articular cartilage degeneration, synovitis, and osteophyte formation. RESULTS: Both ACL injury and surgery resulted in loss of epiphyseal trabecular bone (-27-32%) and reduced voluntary movement at early time points. Joint restabilization successfully lowered OA score (-78% relative to injured at day 14, p<0.0001), and synovitis scores (-37% relative to injured at day 14, p=0.042), and diminished the formation of chondrophytes/osteophytes (-97% relative to injured at day 14, p<0.001, -78% at day 49, p<0.001). CONCLUSIONS: This study confirmed that surgical knee restabilization was effective at reducing articular cartilage degeneration and diminishing chondrophyte/osteophyte formation after ACL injury in mice, suggesting that these processes are largely driven by joint instability in this mouse model. However, restabilization was not able to mitigate the early inflammatory response and the loss of epiphyseal trabecular bone, indicating that these processes are independent of joint instability.

Trends in Orthopaedic Surgery Workforce Diversity: Analyzing Changes Over Time.

INTRODUCTION: There are many reasons why orthopaedic surgeons move or change careers. We asked the questions: (1) What is the geographic distribution of orthopaedic surgeons with respect to age, sex, and race and ethnicity? (2) How has our workforce changed over time with regard to these factors? (3) Are there any patterns or trends detected regarding policy or regulatory events that coincide with these differences? METHODS: The American Academy of Orthopaedic Surgeons surveys over 30,000 members, collecting data on demographics, age, race sex, and practice statistics. We calculated geographic distributions and evaluated these differences over time-potential influences from malpractice suits or tort reform were investigated. RESULTS: Overall surgeon density increased over time. The largest negative changes were noted in District of Columbia, Wyoming, and North Dakota and positive changes in Colorado, South Dakota, and West Virginia. Age across all states increased (mean 1.7 years). Number of female surgeons increased in most states (4.6% to 5.7%). Number of African Americans increased from 1.6% to 1.8%, Hispanic/LatinX from 1.8% to 2.2%, Asian from 5.5% to 6.7%, and multiracial from 0.8% to 1.2%. No change was noted in the percentage of Native American surgeons. DISCUSSION: Surgeon density increased from 2012 to 2018; the cause for this change was not evident. Small increases in surgeon population, female surgeons, and in some underrepresented minorities were seen.

A novel scale for the evaluation of physician drawn medical illustrations.

Effective communication is a crucial component of patient-centered care and individuals with low health literacy face significant challenges in managing their health, leading to longer hospital stays and worse outcomes. Visual aids, such as medical illustrations and pictograms, can enhance patient understanding and memory retention; however, there is a lack in the medical field of tools for evaluating and improving a physician's ability to draw clinical illustrations for their patient. This article explores an aesthetic scale created in collaboration between Boston University Medical School and the Boston University Fine-Arts department. The scale scores basic design elements that could reasonably be improved in a clinical setting. A pilot study demonstrated interrater reliability between trained artists scoring images of varying concepts and visual quality with a Cronbach's alpha of 0.95. This scale has potential use in medical visual education and clinical evaluation.

Comparing the effectiveness of robot-based to human-based intervention in improving joint attention in autistic children.

Background: Children with autism have impairments in initiation of joint attention (IJA) and response to joint attention (RJA). Aims: The present study compared the learning effectiveness of robot-based intervention (RBI) with that of content-matched human-based intervention (HBI) in improving joint attention (JA). We examined whether RBI would enhance RJA, in comparison to HBI. We also examined whether RBI would increase IJA, in comparison to HBI. Methods and procedures: Thirty-eight Chinese-speaking children with autism aged 6 to 9 years were randomly assigned to RBI and HBI groups. Before intervention, their autism severity, cognitive abilities, and language skills were assessed. Each child received six 30-min training sessions over 3 weeks. During training, he/she watched one or two robot/human dramas twice where two robot/human actors demonstrated eye contact and RJA. Outcomes and results: Children in the RBI (but not HBI) group produced more RJA and IJA behaviors in the delayed post-test than in the pre-test. Parents of the RBI children rated the program more positively than those of the HBI children. Conclusions and implications: RBI may be more effective than HBI in promoting JA in autistic children with high support needs. Our findings shed light on the application of robot dramas in enhancing social communication skills.

Improving Technical Outcome in Osteochondral Allograft Transplantation of the Femoral Trochlea: The Role of Contoured Guides, Experience Level, Graft Size, and Graft Position.

Background: The use of coring instrumentation for osteochondral allograft (OCA) transplantation of the femoral trochlea is challenging due to the complex topography of this anatomical area. Purpose: We sought to determine the effect of flat guides versus guides contoured to the surface of the trochlea on graft step-off in trochlear OCAs performed on a foam bone model. We also determined the effect of surgeon experience level and graft size on step-off. Study Design: Controlled laboratory study. Methods: Allograft harvesters were produced in 3 different sequential sizes with either a flat or a contoured undersurface. The guides matched one another in all aspects of shape and size except for the undersurface contour. The contoured undersurface generally matched the surface of the bone model trochlea but was not customized to that surface. A total of 72 foam femora were obtained. Identical trochlear stellate lesions of 3 different sizes (small, medium, and large) were created using 3-dimensional printed surface templates. A total of 6 surgeons (3 attending and 3 resident surgeons) performed OCAs of each trochlear lesion. Each surgeon performed 1 graft for each size and each guide type (n = 6 per surgeon). A specialized digital caliper was prepared that allowed the measurement of graft step-off to within 0.01 mm at a distance of 5 mm between the 2 sensors. The measurements were performed at 8 positions around the clockface of the grafts. Results: Grafts performed with the contoured guides had a mean step-off of 0.43 ± 0.37 mm. Grafts performed with the flat guides had a mean step-off of 0.74 ± 0.78 mm (P < .0001). Experience level did not have a significant effect on graft step-off (P = .81). There was no identifiable pattern indicating higher step-off at any one position on the clockface. Conclusion: In this study, contoured grafts had significantly lower step-offs compared with flat guides. Experience level, clockface position, and graft size did not affect step-off.

Chondrocalcinosis and Osteoarthritis: A Literature Review.

OBJECTIVE: The objective of this study was to review the literature on associations between chondrocalcinosis (CC) and osteoarthritis (OA) and to examine the role of colchicine, previously established as effective for calcium pyrophosphate deposition disease, in the treatment of OA. METHODS: A literature search for mechanistic and clinical studies published between 1990 and 2021 listed in PubMed was performed and studies were included if they examined the associations between OA and CC or colchicine using relevant search terms. RESULTS: Published evidence suggests significant radiographic and mechanistic associations between knee OA and knee CC, but there are only a limited number of studies demonstrating associations between OA and CC in the hips, hands, and ankles. We examined three studies testing the efficacy of colchicine on treatment of pain in OA and found insufficient evidence to definitively establish that colchicine is effective to ameliorate symptoms of OA, although differences in study methodologies and inclusion criteria may explain inconsistent study findings. CONCLUSION: An association between CC and OA is supported at the knee joint in both radiographic and in-vitro studies, but is less definite when the relationship is evaluated at other joints, including at the hips, hands, and ankles. Further research is required to ascertain whether CC modifies symptoms in patients with osteoarthritis or is associated with OA progression. It may be worthwhile to further evaluate colchicine or other agents for potential symptom modifying roles in OA or in OA with CC.

Robot dramas may improve joint attention of Chinese-speaking low-functioning children with autism: stepped wedge trials.

INTRODUCTION: Children with autism spectrum disorder (ASD), especially those with low cognitive functioning, have deficits in joint attention. Previous research has found that these children are interested in engaging with social robots. PURPOSE: In the present study, we designed a robot drama intervention for promoting responses to joint attention abilities (RJA) of children with low-functioning autism (IQs < 70). MATERIALS AND METHODS: Using a stepped wedge design, Chinese-speaking children aged six to eight were randomly assigned to three tiers (N = 18). Children of all three tiers had comparable autism severity, language and cognitive function, and joint attention abilities. Tier 1 first received intervention, followed by Tiers 2 and 3. They watched six dramas in which social robots demonstrated RJA behaviours. RESULTS: The RJA of children of all tiers improved after intervention and such improvement was maintained over time. Despite initiation of joint attention (IJA) not being explicitly taught, IJA of all children was found to improve after intervention. CONCLUSIONS: It was, therefore, concluded that a robot drama could enhance the joint attention of children with low-functioning ASD.Implications for rehabilitationIn comparison to typically developing children, children with autism spectrum disorder (ASD), especially those with low cognitive functioning, have deficits in joint attention.Robot-based drama intervention program was developed to promote responses to joint attention (RJA) abilities of children with low-functioning autism (IQs < 70).Modelling RJA in robot dramas can promote RJA abilities in these children.An improvement in RJA also yielded an increase in the initiation of joint attention (IJA) abilities.Children with low-functioning autism might be able to extract the initiation of joint attention skills from the drama, even though these behaviours were not explicitly taught.

A Fresh Glimpse into Cartilage Immune Privilege.

The increasing prevalence of degenerative cartilage disorders in young patients is a growing public concern worldwide. Cartilage's poor innate regenerative capacity has inspired the exploration and development of cartilage replacement treatments such as tissue-engineered cartilages and osteochondral implants as potential solutions to cartilage loss. The clinical application of tissue-engineered implants is hindered by the lack of long-term follow-up demonstrating efficacy, biocompatibility, and bio-integration. The historically reported immunological privilege of cartilage tissue was based on histomorphological observations pointing out the lack of vascularity and the presence of a tight extracellular matrix. However, clinical studies in humans and animals do not unequivocally support the immune-privilege theory. More in-depth studies on cartilage immunology are needed to make clinical advances such as tissue engineering more applicable. This review analyzes the literature that supports and opposes the concept that cartilage is an immune-privileged tissue and provides insight into mechanisms conferring various degrees of immune privilege to other, more in-depth studied tissues such as testis, eyes, brain, and cancer.

Longitudinal antibody responses to peanut following probiotic and peanut oral immunotherapy (PPOIT) in children with peanut allergy.

INTRODUCTION: Probiotic and Peanut Oral Immunotherapy (PPOIT) is effective at inducing sustained unresponsiveness (SU) at end-of-treatment and this effect persists up to four years post-treatment, referred to as persistent SU. We sought to evaluate (i) how PPOIT altered peanut-specific humoral immune indices, and (ii) how such longitudinal indices relate to persistent SU. METHODS: Longitudinal serum/plasma levels of whole peanut- and peanut component- (Ara-h1, -h2, -h3, -h8, -h9) specific-IgE (sIgE) and specific-IgG4 (sIgG4) antibodies were measured by ImmunoCAP and salivary peanut-specific-IgA (sIgA) by ELISA in children (n=62) enrolled in the PPOIT-001 randomised trial from baseline (T0) to 4-years post-treatment (T5). Multivariate regression analyses of log-transformed values were used for point-in-time between group comparisons. Generalised estimating equations (GEE) were used for longitudinal comparisons between groups. RESULTS: PPOIT was associated with changes in sIgE and sIgG4 over time. sIgE levels were significantly reduced post-treatment [T5, PPOIT v.s. Placebo ratio of geometric mean (GM): Ara-h1 0.07, p=0.008; Ara-h2 0.08, p=0.007; Ara-h3 0.15, p=0.021]. sIgG4 levels were significantly increased by end-of-treatment (T1, PPOIT v.s. Placebo ratio of GM: Ara-h1 3.77, p=0.011; Ara-h2 17.97, p<0.001; Ara-h3 10.42, p<0.001) but levels in PPOIT group decreased once treatment was stopped and returned to levels comparable with Placebo group by T5. Similarly, salivary peanut sIgA increased during treatment, as early as 4 months of treatment (PPOIT v.s. Placebo, ratio of GM: 2.04, p=0.014), then reduced post-treatment. CONCLUSION: PPOIT was associated with broad reduction in peanut specific humoral responses which may mediate the clinical effects of SU that persists to 4-years post-treatment.

The immediate meniscal allograft transplantation achieved better chondroprotection and less meniscus degeneration than the conventional delayed transplantation in the long-term.

PURPOSE: The purpose of this study was to compare the long-term clinical and radiological outcomes between the immediate and delayed meniscus allograft transplantation (MAT). METHODS: Nine menisci were transplanted immediately after total meniscectomy (immediate group, IM), and 10 menisci were delayed transplanted in patients with the median of 35 months (range 9-92 months) after total meniscectomy (delayed group, DE). Patient's subjective clinical outcomes including VAS, IKDC, Lysholm and Tegner scores as well as muscle strength measures were compared. Joint degeneration was evaluated by both radiographs to assess joint space width narrowing, Kellegren-Lawrence (KL) grade and MRI with T2 mapping sequences to quantitatively analyze both cartilage and meniscal allograft degeneration. RESULTS: The median follow-up time was 10.8 years (range 10-14 years). The IKDC (IM vs DE, 89.8 vs 80.9, n.s.) and Lysholm scores (IM vs DE, 87.7 vs 78.0, n.s.) were close in two groups, while the IM group showed slightly lower VAS (IM vs DE, 0.2 vs 1.5, p = 0.031), higher Tegner score (IM vs DE, 7 vs 3.5 p = 0.021) and better quadriceps muscle strength. The IM group had less joint space narrowing (IM vs DE, 0.35 mm vs 0.71 mm, n.s.), less KL grade progression (IM vs DE, 0.6 vs 1.7, p = 0.041) on radiographs and less chondral lesions development on MRIs (Cartilage Degeneration Index, IM vs DE, 252 vs 2038, p = 0.025). All meniscal grafts exhibited degeneration by showing grade 3 signal on MRI, and 4 (4/9) in the IM group and 8 (8/10) cases in the DE group. The T2 value of cartilage and meniscal allograft in the IM group was close to that of the healthy control and was significantly lower than that of the DE group. CONCLUSION: Compared to the conventional delayed MAT, the immediate MAT achieved better cartilage and meniscus protection in the long-term, while its superiority in patient-reported outcomes was limited. LEVEL OF EVIDENCE: IV.

Real-world incidence of venetoclax toxicities in British Columbia.

INTRODUCTION: Venetoclax is used to treat relapsed/refractory chronic lymphocytic leukemia (r/r CLL). Tumour lysis syndrome (TLS) is a serious toxicity associated with venetoclax, and real-world studies suggest that the incidence may be higher than in clinical trials. The purpose of this study is to describe the incidence of venetoclax toxicities in British Columbia (BC). METHODS: Retrospective review of electronic medical charts for patient characteristics and clinical outcomes of patients treated with venetoclax for r/r CLL in BC. Patients were classified according to their risk for developing TLS. The incidence of TLS was categorized based on laboratory metrics or clinical diagnosis. Other non-TLS toxicities were also collected. RESULTS: Of 33 patients identified, 40%, 33%, and 27% were at low, intermediate, and high risk for TLS, respectively. Laboratory TLS occurred in 1/33 patients (3%), and no clinical TLS was reported. Grade 3 or 4 toxicities occurred in 19/33 patients (58%). Of these, neutropenia was the most common, occurring in 16 patients (84%) followed by thrombocytopenia, which occurred in 8 patients (42%). CONCLUSIONS: The incidence of TLS in patients treated with venetoclax for r/r CLL in BC was lower than in other real-world studies. Findings may warrant further investigation to determine if the higher incidence of TLS in real-world reports may be mitigated through modifying TLS risk categorization and associated prophylactic measures. Neutropenia was the most common grade 3 or 4 venetoclax toxicity reported, and the incidence in BC is comparable to other centres.

Prospective clinical trial on the learning curve of high-intensity-focused ultrasound for the treatment of breast fibroadenoma.

INTRODUCTION: High-intensity-focused ultrasound (HIFU) is a safe and feasible treatment option for breast fibroadenoma. However, its learning curve has not been described in the medical literature. METHODS: All patients with biopsy-proven fibroadenoma considered indicated for HIFU were screened for eligibility for HIFU treatment. A total of 60 patients were recruited according to the pre-defined sample size calculation. RESULTS: Sixty consecutive patients were divided into three cohorts in chronological order. The mean tumor volume shrinkage rates in cohorts 1, 2, and 3 at 6 months post-HIFU ablation were 38%, 34%, and 59%, respectively. Significant tumor shrinkage was observed from case 41 onward (p < 0.0001). Similarly, the mean tumor volume shrinkage rates in cohorts 1, 2, and 3 at 12 months post-HIFU ablation were 45%, 51%, and 71%, respectively. Significant tumor shrinkage was observed from case 41 onwards (p < 0.0473). The mean procedure time for the first 20 patients was 48.5 (range 45-75) minutes, while that in the second 20 patients was 39.7 (range 20-60) minutes, and that in the last 20 patients was 28.9 (range 15-45) minutes. The treatment time was significantly shorter from case 41 onwards (p = 0.0481). CONCLUSION: Treatment outcomes and treatment time improved significantly after performing approximately 40 HIFU procedures.

Examining Phenotypical Heterogeneity in Language Abilities in Chinese-Speaking Children with Autism: A Naturalistic Sampling Approach.

Phenotypical heterogeneity in language abilities is a hallmark of autism but remains poorly understood. The present study collected naturalistic language samples from parent-child interactions. We quantified verbal abilities (mean length of utterance, tokens, types) of 50 Chinese-speaking children (M = 5; 6) and stratified subgroups based on their autism traits, IQ, and language abilities. Using hierarchical cluster analysis, four groups were identified. Group 1, the least affected group, had mild autism, the highest IQ, and the strongest verbal abilities. Group 2, the severely affected group, had the lowest IQ, most severe autism symptoms, and weakest verbal abilities. Group 3 and Group 4 displayed average levels of verbal abilities and IQ. These findings may characterize the heterogeneous profiles of verbal abilities in Chinese-speaking children.

Next Steps: Advocating for Women in Orthopaedic Surgery.

Orthopaedic surgery is the least diverse of all medical specialties, by both sex and race. Diversity among orthopaedic trainees is the lowest in medicine, and growth in percentage representation is the lowest of all surgical subspecialties. Women comprise only 6% of orthopaedic surgeons and 16% of orthopaedic surgery trainees. This extreme lack of diversity in orthopaedics limits creative problem-solving and the potential of our profession. Women in orthopaedics encounter sexual harassment, overt discrimination, and implicit bias, which create barriers to training, career satisfaction, and success. Women are underrepresented in leadership positions, perpetuating the lack of diversity through poor visibility to potential candidates, which impedes recruitment. Correction will require a concerted effort, as acknowledged by the American Academy of Orthopaedic Surgeons leadership who included a goal and plan to increase diversity in the 2019 to 2023 Strategic Plan. Recommended initiatives include support for pipeline programs that increase diversity of the candidate pool; sexual harassment and implicit bias acknowledgement, education, and corrective action; and the active sponsorship of qualified, capable women by organizational leaders. To follow, women will lend insight from their diverse viewpoints to research questions, practice problems, and clinical conundrums of our specialty, augmenting the profession and improving patient outcomes.

International Orthopaedic Volunteer Opportunities in Low and Middle-Income Countries.

ABSTRACT: Globally, the burden of musculoskeletal conditions continues to rise, disproportionately affecting low and middle-income countries (LMICs). The ability to meet these orthopaedic surgical care demands remains a challenge. To help address these issues, many orthopaedic surgeons seek opportunities to provide humanitarian assistance to the populations in need. While many global orthopaedic initiatives are well-intentioned and can offer short-term benefits to the local communities, it is essential to emphasize training and the integration of local surgeon-leaders. The commitment to developing educational and investigative capacity, as well as fostering sustainable, mutually beneficial partnerships in low-resource settings, is critical. To this end, global health organizations, such as the Consortium of Orthopaedic Academic Traumatologists (COACT), work to promote and ensure the lasting sustainability of musculoskeletal trauma care worldwide. This article describes global orthopaedic efforts that can effectively address musculoskeletal care through an examination of 5 domains: clinical care, clinical research, surgical education, disaster response, and advocacy.

Higher SARS-CoV-2 viral loads correlated with smaller thyroid volumes on ultrasound among male COVID-19 survivors.

PURPOSE: Thyroid dysfunction, including thyroiditis, is well recognized in COVID-19 patients. We evaluated thyroid ultrasonographic features among COVID-19 survivors, which are less well known. METHODS: Adult COVID-19 survivors without known thyroid disorders who attended dedicated COVID-19 clinic underwent thyroid ultrasonography and assessment of thyroid function and autoimmunity. Adults admitted for acute non-thyroidal surgical problems and negative for COVID-19 were recruited as control. SARS-CoV-2 viral load (VL) was presented as the inverse of cycle threshold values from the real-time reverse transcription-polymerase chain reaction of the respiratory specimen on admission. RESULTS: In total, 79 COVID-19 patients and 44 non-COVID-19 controls were included. All abnormal thyroid function tests during acute COVID-19 recovered upon follow-up. Thyroid ultrasonography was performed at a median of 67 days after acute COVID-19. The median thyroid volume was 9.73 mL (IQR: 7.87-13.70). In multivariable linear regression, SARS-CoV-2 VL on presentation (standardized beta -0.206, p = 0.042) inversely correlated with thyroid volume, in addition to body mass index at the time of ultrasonography (p < 0.001). Sex-specific analysis revealed similar results among men but not women. Eleven COVID-19 patients (13.9%) had ultrasonographic changes suggestive of thyroiditis, comparable to non-COVID-19 patients (p = 0.375). None of these 11 patients had isolated low thyroid-stimulating hormone levels suggestive of thyroiditis at initial admission or the time of ultrasonography. CONCLUSIONS: Higher SARS-CoV-2 VL on presentation were associated with smaller thyroid volumes, especially in men. Further research is suggested to investigate this possible direct viral effect of SARS-CoV-2 on the thyroid gland. There was no increased rate of ultrasonographic features suggestive of thyroiditis in COVID-19 survivors.

Prognostic Factors to Determine Survivorship of Meniscal Allograft Transplant: A Systematic Review.

BACKGROUND: There is much room for improvement and optimization of meniscal allograft survivorship. PURPOSE: To understand prognostic factors for survivorship using evidence-based selection criteria in order to identify patients who would best benefit from meniscal allograft transplant (MAT). STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: We conducted this systematic review to analyze prognostic factors for survivorship of MAT. The Cochrane Central Register, PubMed publisher, Embase.com, and Web of Science databases were searched through August 8, 2019. Included studies entailed patients of any age who received MAT with a reported association between prognostic factors and survivorship of the allograft. Two reviewers independently screened all titles and abstracts for eligibility, extracted the data, assessed the risk of bias using the Newcastle-Ottawa Scale, and performed a best-evidence synthesis. RESULTS: The review included 18 studies with a total of 1920 patients. The mean follow-up time was 6.0 years (range, 2.1-11.2 years). A total of 20 prognostic factors were identified and shown to be associated with survivorship of MAT. Strong evidence was found that severe cartilage damage was associated with poor survivorship. Strong evidence was also found showing that sex, knee compartment, surgical side, concomitant anterior cruciate ligament (ACL) reconstruction, and concomitant osteotomy for malalignment had no effect on survivorship. Moderate evidence was found that body mass index (<36), tobacco use, and arthroscopic versus open procedure had no influence on survivorship. Conflicting evidence was found that older age and kissing cartilage lesions (lesions on both the femur and tibia vs on a single side) decreased survivorship. CONCLUSION: Severe cartilage damage decreases the survivorship of MAT. Concomitant ACL reconstruction and osteotomy showed no relationship to survivorship. Many determinants showed conflicting and limited evidence. Older age may be of interest and should be further studied.

Consensus on Rehabilitation Guidelines among Orthopedic Surgeons in the United States following Use of Third-Generation Articular Cartilage Repair (MACI) for Treatment of Knee Cartilage Lesions.

OBJECTIVE: The 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. DESIGN: A 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. RESULTS: Consensus (>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. CONCLUSIONS: Good 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.