Husen, Martin

There is a context-dependent trade-off in body size of elite runners, such that smaller body sizes are observed among longer distance runners. However, it is unclear whether this trade-off in body size is observed in other Olympic sports, such as cycling and swimming. To understand the association between body size and athletic competition, we examined metrics of body size from male and female Olympic athletes competing in swimming, running, and cycling. We collected standard anthropometrics (height, mass, body mass index (BMI), and body surface area) of elite male and female athletes competing in the London 2012 Summer Olympics from a public repository. Anthropometric data were compared between sexes (male and female); between sports (swimming, running, and cycling); and between distances within sports (shorter and longer distance). Males were taller ( P < 0.001), heavier ( P < 0.001), and had a larger BMI ( P < 0.001) compared to females. Relative to athletes competing in longer distance events, athletes competing in shorter distance were generally taller (running: P < 0.001, swimming: P ≤ 0.014) and heavier (running: P < 0.001, swimming: P = 0.002 (males) and P = 0.148 (females), cycling: P < 0.001) for both males and females. Height was not different between shorter and longer distance cyclists. There was a trade-off between body size and distance for each of the three Olympics sports, such that smaller athletes were observed in longer distance events. Although there were large sex-based differences in body size, similar trade-offs in size and event were observed for both males and females. These data suggest that there is an optimal combination of skeletal muscle mass and body size to optimize movement economy that is generally preserved across different modes of human locomotion.

Objectives: Meniscal allograft transplantation (MAT) is an accepted and effective treatment option in the context of unsalvageable menisci, particularly in young and active patients. It has been shown to reduce pain and improve knee function in previously symptomatic patients. However, there is still limited knowledge about the long-term survival rates of allografts, the durability of clinical results, and the influence of patient-specific parameters, such as leg alignment, tibial slope, and preoperative International Cartilage Regeneration & Joint Preservation Society (ICRS) grade. The purpose of this study was to determine (1) the long-term clinical success rate after MAT with bony fixation in a large, single-center cohort of consecutive patients, and (2) if patient-specific and procedural variables influence the clinical, anatomic, and subjective outcomes and risk of failure. Methods: Data on 185 consecutive knees undergoing MAT in a single institution were prospectively collected and screened for inclusion in this study. The minimum follow-up time was 2 years. Radiographic variables (International Cartilage Regeneration & Joint Preservation Society [ICRS] grade and Kellgren and Lawrence grade) were assessed preoperatively and at follow-up. Subjective patient-reported outcome measures (PROMs), Lysholm score, Knee Disability and Osteoarthritis Outcome Score (KOOS) including subscores, International Knee Documentation Committee (IKDC) score, and visual analog score (VAS) were collected preoperatively and at follow-up. Clinical failure was defined as revision surgery due to graft failure or conversion to total knee arthroplasty (TKA). Anatomic failure was considered a tear covering >20% of the allograft, any peripheral tear, and unstable peripheral fixation leading to dislocation of the graft. Subjective failure was defined as Lysholm score ≤65. Preoperative tibial slope and leg alignment were assessed. Survival analyses were performed utilizing the Kaplan-Meier estimate. Univariate and multivariate analyses were performed to determine risk factors for clinical and anatomic failure. Results: A total of 157 knees met inclusion criteria (Table 1). After a mean follow-up time of 7 ± 3.5 years, 127 (80.9%) knees were free of clinical, anatomic, and subjective failure. Fourteen (8.9%) knees experienced clinical failure, 26 (16.6%) knees were identified as anatomic failure, and 13 patients (8.3%) suffered from subjective failure with a reported Lysholm score of ≤65 at a mean follow-up of 7 years. Concurrent osteochondral allograft transplantation was identified as a predictor of both clinical (HR 4.55; 95% CI 1.46-14.17; p=0.009) and anatomic failure (HR 3.05; 95% CI 1.34-6.92; p=0.008). Cartilage damage of ICRS grade 3 or 4 of the index compartment conveyed an increased risk for clinical (HR 3.41; 95% CI 1.05-11.01; p=0.04) and anatomic failure (HR 3.04; 95% CI 1.31-7.11; p=0.01) (Table 2). There were no differences in outcomes between medial and lateral MAT. High-grade cartilage damage (defined as ICRS grades 3 and 4) preoperatively (HR 10.67; 95% CI 1.037-109.768; p=0.046), patients age over 25 (HR 5.44; 95% CI 0.120-246.070; p=0.384), and a body mass index >30 (HR 2.24; 95% CI 0.748-6.705; p=0.149) were associated with subjective failure. Considering the entire study population, PROMs including KOOS and IKDC were significantly improved at final follow-up compared to preoperative scores across all measurements (p<0.005). Conclusions: MAT showed good-to-excellent clinical results at a mean follow-up of 7 years. Low ICRS lesion grade was associated with a higher clinical and anatomic survival rate. Patients with concurrent osteochondral allograft transplantation are at higher risk of clinical and anatomic failure, but still report significantly improved PROMs. These results suggest MAT has a lasting beneficial effect both as in isolation and in complex cases with one or more concurrent procedures.

Background: Osteochondral allograft transplantation (OCAT) is an accepted knee joint–preserving treatment strategy for focal osteochondral lesions that is often conducted in combination with meniscal allograft transplantation (MAT). Despite its frequent and simultaneous utilization, there remains a lack in the literature reporting on outcomes and failure rates after concomitant procedures. Purpose: To determine (1) the midterm clinical success rate after OCAT+MAT in comparison with a matched-pair cohort undergoing isolated OCAT, (2) whether patient-specific and procedural variables influence the risk of failure, and (3) patient-reported outcome measures over time. Study Design: Cohort study; Level of evidence, 3. Methods: A single-center matched-pair cohort study was conducted investigating outcomes in patients who underwent OCAT of the medial or lateral femoral condyle with and without MAT between 2004 and 2020. Patients were matched 1:1 by age (±5 years), sex (male or female), body mass index (±5), and grouped Kellgren and Lawrence grade (grades 0-1 or 2-4). The minimum follow-up time was 2 years. Radiographic variables (International Cartilage Regeneration & Joint Preservation Society [ICRS] grade and Kellgren and Lawrence grade) were assessed preoperatively and at follow-up. Subjective patient-reported outcome measures (Lysholm score, Knee injury and Osteoarthritis Outcome Score [KOOS] including subscores, International Knee Documentation Committee [IKDC] score, and visual analog scale score) were collected preoperatively and at follow-up. Clinical failure was defined as revision surgery for graft failure or conversion to total knee arthroplasty. Patient-reported, clinical, and radiographic outcomes were compared between groups. Results: In total, 66 patients (33 treated with isolated OCAT, 33 treated with OCAT+MAT; 57.6% male) with a mean age of 26.3 years (range, 18-62 years) were followed for a mean of 5.6 years (minimum, 2 years; range, 24-218 months). The 2 cohorts showed no difference in Kellgren and Lawrence grade postoperatively ( P = .59). There was a significantly higher ICRS grade detected at follow-up in the OCAT+MAT group (2.81 ± 1.10) compared with the OCAT group (2.04 ± 0.96) ( P < .05). There were no statistically significant differences between the groups regarding reoperation rate (OCAT: n = 6; OCAT+MAT: n = 13; P = .116), time to reoperation (OCAT: 46.67 ± 47.27 months vs OCAT+MAT: 28.08 ± 30.16 months; P = .061), and failure rate (OCAT: n = 4 [12.1%] vs OCAT+MAT: n = 5 [15.2%]; P = .66). In the OCAT+MAT group, an increase of tibial slope by 1° conferred a 1.65-fold increase in the hazard for failure over decreased slope (hazard ratio, 1.65; 95% CI, 1.10-2.50; P < .05). The overall survival rate was 86% at a mean follow-up of 5.6 years. Patient-reported outcome scores were significantly improved at the final follow-up compared with preoperative status. No significant differences were seen between groups with respect to subjective IKDC, Lysholm, Tegner, and KOOS results, except for the KOOS Symptoms subscale score, which was significantly higher in the OCAT+MAT group than in the OCAT group (mean difference, 14.6; P < .05) and did exceed the minimal clinically important difference threshold of 10.7. Conclusion: Midterm results after isolated OCAT and OCAT+MAT show high rates of healing and sustainable subjective improvement of knee function and quality of life. However, it should be noted that the difference in reoperation rate and time to reoperation between the groups is arguably clinically important and that lack of statistical significance may be because of low power. These results imply that isolated OCAT is an efficient joint-preserving treatment that can be combined with MAT in well-selected patients with meniscal insufficiency without negative influence on global clinical outcomes.

Objective This proof-of-concept study investigated an improved cell-based injection therapy combining mesenchymal stem cells (MSCs) and meniscus cells (MCs) to support superior meniscus allograft repopulation and early revival compared to injecting MSCs alone. Design In this controlled laboratory study, frozen meniscus allograft samples were injected vertically with a cell suspension containing different ratios of MSCs and MCs or control (lactated ringers) and cultured for 28 days. Samples were analyzed weekly for cell viability, migration, and metabolism using histological and biochemical assays. Tissue medium was analyzed for matrix metalloproteinase (MMP) expression using zymography. Results Cellular repopulation of frozen allografts injected with different cell suspensions was validated by immunohistochemistry. Significant higher DNA content was evidenced in grafts treated with suspensions of MCs or MC:MSC (1:4 ratio). Cell metabolic activity was significantly different between all treated groups and control group after 1 week. Allografts injected with MCs showed significantly more cell proliferation than injections with MSCs. MMP2 activity was detected in medium of all grafts cellularized with MCs with or without MSCs. Scanning electron microscopy (SEM) analysis showed resolution of the needle puncture, but not in the control group. Cell labeling of MCs upon injection of mixed MC:MSC suspensions revealed a gradual increase in the cell ratio. Conclusions The findings of this study establish that injection of MCs with or without MSCs enhances the cellularity of meniscus allograft to support early graft revival and remodeling.

Case: A 29-year-old man sustained a bilateral acute patellar tendon rupture (PTR) while jumping on a trampoline. He was initially treated with bilateral transosseous patellar tendon repairs. Bilateral rerupture occurred during a fall 10 weeks after. He subsequently underwent staged bilateral patellar tendon reconstructions using an Achilles tendon allograft. At 3-year follow-up, he has maintained full range of motion and leg strength without rerupture or other complications. Conclusion: The use of Achilles tendon allograft in the presence of inadequate and poor-quality tendon tissue for reconstruction of the patellar tendon in the revision setting is a viable and effective treatment option.

Background: Meniscal allograft transplantation (MAT) is an accepted and effective treatment option in the context of unsalvageable menisci, particularly in young and active patients. It has been shown to reduce pain and improve knee function in previously symptomatic patients. However, there is still limited knowledge about the long-term survival rates of allografts, the durability of clinical results, and the influence of patient-specific parameters, such as leg alignment, tibial slope, and preoperative International Cartilage Regeneration & Joint Preservation Society (ICRS) grade. Purpose: To determine (1) the long-term clinical success rate after MAT with bony fixation in a large, single-center cohort of consecutive patients, and (2) if patient-specific and procedural variables influence the clinical, anatomic, and subjective outcomes and risk of failure. Study Design: Case-control study; Level of evidence, 3. Methods: Data on 185 consecutive knees undergoing MAT in a single institution were prospectively collected and screened for inclusion in this study. The minimum follow-up time was 2 years. Radiographic variables (ICRS grade and Kellgren-Lawrence grade) were assessed preoperatively and at follow-up. Subjective patient-reported outcome measures (PROMs) (Lysholm score, Knee injury and Osteoarthritis Outcome Score [KOOS] including subscores, International Knee Documentation Committee [IKDC] score, and visual analog scale [VAS] score) were collected preoperatively and at follow-up. Clinical failure was defined as revision surgery due to graft failure or conversion to total knee arthroplasty. Anatomic failure was considered a tear covering >20% of the allograft, any peripheral tear, and unstable peripheral fixation leading to dislocation of the graft. Subjective failure was defined as Lysholm score ≤65. Preoperative tibial slope and leg alignment were assessed. Survival analyses were performed using the Kaplan-Meier estimate. Univariate and multivariate analyses were performed to determine risk factors for clinical and anatomic failure. Results: A total of 157 knees met inclusion criteria. After a mean follow-up time of 7 ± 3.5 years, 127 (80.9%) knees were free of clinical, anatomic, and subjective failure. Fourteen (8.9%) knees experienced clinical failure, 26 (16.6%) knees were identified as having experienced anatomic failure, and 13 (8.3%) patients experienced subjective failure with a reported Lysholm score of ≤65 at a mean follow-up of 7 years. Concurrent osteochondral allograft transplantation was identified as a predictor of both clinical (hazard ratio [HR], 4.55; 95% CI, 1.46-14.17; P = .009) and anatomic (HR, 3.05; 95% CI, 1.34-6.92; P = .008) failure. Cartilage damage of ICRS grade 3 or 4 of the index compartment conveyed an increased risk for clinical (HR, 3.41; 95% CI, 1.05-11.01; P = .04) and anatomic (HR, 3.04; 95% CI, 1.31-7.11; P = .01) failure. High-grade cartilage damage preoperatively (HR, 10.67; 95% CI, 1.037-109.768; P = .046), patient age >25 years (HR, 5.44; 95% CI, 0.120-246.070; P = .384), and a body mass index >30 (HR, 2.24; 95% CI, 0.748-6.705; P = .149) were associated with subjective failure. PROMs including KOOS and IKDC were significantly improved at final follow-up compared with preoperative scores across all measurements ( P < .005). Conclusion: MAT showed good to excellent clinical results at a mean follow-up of 7 years. Low ICRS lesion grade was associated with a higher clinical and anatomic survival rate. Patients with concurrent OCA transplantation are at a higher risk of clinical and anatomic failure, but still report significantly improved PROMs. These results suggest that MAT has a lasting beneficial effect both in isolation and in complex cases with ≥1 concurrent procedures.

Background: Osteochondritis dissecans (OCD) of the knee is a rare but potentially incapacitating disorder in which subchondral bone detaches, leading to an osteochondral fragment that can become unstable and progress into a loose body. The exact cause is unknown, although several biological and mechanical factors have been described. Purpose: To provide insight into epidemiological data of a large cohort of patients affected by OCD of the knee and to identify potential factors contributing to the cause of this disorder. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 236 patients (259 knees) affected by OCD were included in our Knee Registry (2005-2022) and retrospectively analyzed. Patient characteristics were extracted from the medical records. Location and International Cartilage Regeneration & Joint Preservation Society grade (1-4) of OCD were assessed using magnetic resonance imaging. If available, a full-leg standing radiograph was used to assess alignment. Additionally, a statistical scoring system for instability risk was created. Results: A total of 263 OCD lesions were identified in 259 knees, 66.2% on the medial femoral condyle (MFC), 26.6% on the lateral femoral condyle (LFC), 3.8% on the trochlea, 2.7% on the patella, and 0.8% on the lateral tibia plateau. Male patients made up 57.6% of the sample, which had a mean age of 21.8 years. A very high percentage of patients (77.1%; n = 182) practiced sports, of whom 67.6% (n = 123) were engaged in high-impact sports. The location of the OCD lesions and the leg alignment (n = 110) were significantly correlated: MFC lesions were associated with more varus than valgus alignment (47.5% vs 11.3%) and patients with LFC lesions had more valgus than varus alignment (46.7% vs 20.0%; P = .002). Based on age, smoking, sports activity, and preceding trauma, a multivariable scoring system (0-11 points) was created. An increased risk of lesion instability was associated with an increased score: 29.0% at 0 points and 97.0% at 11 points. Conclusion: This study provides detailed epidemiological data for 236 patients affected by OCD of the knee. Older age, smoking, inactivity, and preceding trauma were predictive for instability of OCD lesions. There was an association between OCD of the MFC and varus malalignment and between OCD of the LFC and valgus malalignment. This finding, in combination with the high percentage of patients practicing high-impact sports, suggests an important role for mechanical overload in the pathogenesis of OCD.

Background: Little is known about the specific risk of knee injuries due to trampoline accidents in adults compared with children. Purpose: To investigate the differences in trampoline-related knee injuries between children and adults and identify risk factors and protective strategies to reduce injury incidence. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Data on 229 consecutive patients treated for trampoline-related knee injuries in a single institution were prospectively collected, analyzed, and included. Risk factors, injury patterns, and clinical treatments were compared between skeletally immature and skeletally mature patients. Logistic regression was used to determine the odds ratios for specific risk factors for trampoline-related injuries—including body mass index (BMI), trauma mechanism, patient age, and accident location. Results: A total of 229 patients met the inclusion criteria; 118 (52%) patients (women, 54.2%; mean age, 8.5 ± 4.1 years) were skeletally immature at the time of injury, and 111 (48%) patients (women, 72%; mean age, 31.9 ± 13.1 years) had closed physes on initial presentation and were classified as skeletally mature. A total of 63 patients (28%) required surgical treatment for their knee injury. Overall, 50 anterior cruciate ligament (ACL) tears, 46 fractures, 39 meniscal tears, 31 ligamentous tears other than ACL, 22 patellar dislocations, and 38 soft tissue injuries, such as lacerations, were recorded. Skeletally mature patients had 7.8 times higher odds (95% CI, 1.6-46.8; P < .05) and 19.1 increased odds (95% CI, 5.5-74.9; P < .05) of an ACL tear or another ligamentous tear, respectively, compared with skeletally immature patients. Patients who described instability and giving way of the knee as relevant trauma mechanisms had odds of 3.11 (95% CI, 0.9-14.8; P < .05) of an ACL tear compared with other trauma mechanisms. Meniscal tears were observed more frequently in the skeletally mature cohort ( P < .05). An elevated BMI was associated with a significantly higher relative risk of an ACL tear, a ligamentous tear other than the ACL, and an injury requiring surgery. A third of surgically treated patients were subject to a delayed diagnosis. Conclusion: Adults had a significantly increased risk of ligamentous and meniscal tears and required operative intervention more often than skeletally immature individuals. Elevated BMI, age, and instability events in terms of trauma mechanism conveyed an increased risk of structural damage to the knee.

Background: Femoroacetabular impingement (FAI) is a common cause of hip pain, especially in young patients. When left untreated, it has been demonstrated to be a risk factor for the onset or progression of osteoarthritis (OA) and has been identified as one of the main contributors leading to the need for total hip arthroplasty (THA) at a young age. While the short-term therapeutic potential of hip arthroscopy is widely recognized, little is known regarding its potential mid- to long-term preventive effect on the progression of hip OA. Purpose: To (1) report clinical outcomes of arthroscopically treated FAI syndrome with a minimum 5-year follow-up and compare the results to a cohort with FAI treated nonsurgically and (2) determine the influence of hip arthroscopy on the onset and progression of hip OA in patients diagnosed with FAI. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who had hip pain and were diagnosed with FAI were included. Exclusion criteria were (1) previous or concomitant hip surgery, (2) <5 years of follow-up, and (3) insufficient radiographs. Patients treated with hip arthroscopy were compared with a cohort of patients with FAI who were treated nonsurgically. Kaplan-Meier estimates of failure (defined as conversion to THA) were performed. Bivariate analysis and Cox regression were used to identify factors associated with inferior clinical and radiographic outcomes. Results: A total of 957 patients (650 female, 307 male; 1114 hips) (mean age, 28.03 ± 8.9 years [range, 6.5-41.0 years]) with FAI were included. A total of 132 hips underwent hip arthroscopy and 982 hips were nonoperatively treated. The mean follow-up was 12.5 ± 4.7 years (range, 5.0-23.4 years). At the final follow-up, the rate of OA progression was 26.5% in the operative group and 35.2% in the nonoperative cohort ( P < .01). Conversion to THA was performed in 6.8% of the surgical patients and 10.5% of the initially nonsurgical patients ( P = .19). Additionally, there was no significant difference in the risk of failure between the operatively and nonoperatively treated patients. Male sex, increased age at initial diagnosis, presence of cam morphology, and increased initial Tönnis grade were risk factors for failure (male sex: hazard ratio [HR], 2.3; P < .01; per year of increased age: HR, 1.1; P < .01; presence of cam: HR, 3.5; P < .01; per Tönnis grade: HR, 4.0; P < .01). Conclusion: At a mean follow-up of nearly 13 years, 7% of patients of the surgical group experienced progression to THA, compared with 11% of the nonoperative control group. While most of the operative group showed little to no OA at final follow-up, moderate OA (Tönnis grade 2) was present in 12% of the cohort compared with 22% of nonsurgical patients. Increased age at diagnosis, male sex, presence of a cam morphology, and presence of initial arthritic joint changes were found to be risk factors for failure. The results of this study demonstrated evidence for a preventive effect of hip arthroscopy on the development and progression of OA in young patients with FAI at mid- to long-term follow-up.

Background: Patellar instability has the highest incidence in adolescents aged between 14 and 18 years. The unique relationship between the medial patellofemoral ligament (MPFL) and the distal femoral physis in skeletally immature patients warrants precisely positioned MPFL graft insertion. A paucity of data are available evaluating the results of MPFL reconstruction using allograft tendon before skeletal maturity. Purposes: (1) To assess the results of MPFL reconstruction using allograft tendon in skeletally immature patients by analyzing redislocation and reoperation rates, radiological outcomes, and patient-reported outcomes and (2) to determine whether epidemiological, intraoperative, or radiographic factors influence recurrent instability and clinical outcomes. Study Design: Case series; Level of evidence, 4. Methods: Prospectively collected data were retrospectively analyzed for 69 skeletally immature patients who experienced a first-time or recurrent lateral patellar dislocation and were treated with anatomic MPFL reconstruction. Inclusion criteria were MPFL reconstruction using allograft and the availability of preoperative magnetic resonance imaging scans in the presence of open or partially open physes. Patients with <2 years of follow-up and patients with previous surgeries on the same knee were excluded from the study. Preoperative radiographic imaging was reviewed and analyzed. Trochlear dysplasia, tibial tubercle–trochlear groove distance, and patellar height were evaluated. Descriptive data, concomitant injuries, surgical procedure details, complications, and postoperative history were assessed via review of medical records and patient charts. Validated patient-reported and surgeon-measured outcomes were collected pre- and postoperatively, including Kujala score, Lysholm score, and Tegner activity score. Return-to-sports rate was assessed. The influence of epidemiological, intraoperative, and radiographic parameters on the redislocation rates and clinical outcomes was assessed using a multiple linear regression model. Results: A total of 79 physeal-sparing MPFL reconstructions (69 patients) met the inclusion criteria. The mean age of the patient cohort was 14.7 ± 1.8 years (range, 8.5-16.9 years). Within the mean follow-up time of 37.9 ± 12.1 months (range, 24-85 months after surgery, there were 12 patients with clinical failures resulting in reoperation. Eleven patients experienced a redislocation of the patella, and 1 patient sustained a transverse noncontact patellar fracture 6 months after index surgery that required operative fixation. No injuries to the distal femoral physes were clinically observed. At the final follow-up, patients had a mean Lysholm score (1-100) of 96.5 ± 6.7, a mean Kujala score (1-100) of 96.5 ± 7.4, and a mean Tegner Activity Scale score (1-10) of 4.9 ± 1.3. Patellar height and trochlear dysplasia did not influence redislocation or clinical scores. In total, 57 of the 63 patients (90.5%) who were engaged in sports before injury returned to the same or higher level of competition. In a subgroup analysis of patients who underwent isolated MPFL reconstruction (n = 44) without concomitant procedures, 9 patients (20.5%) experienced failure and had a redislocation. A univariate analysis of hazards for failure based on patient-specific variables was carried out. A body mass index ≥30 conveyed a hazard ratio of 2.51 (95% CI, 0.63-10.1; P = .19), and the tibial tubercle-trochlear groove distance by increments of 1 mm was associated with a hazard ratio of 2.02 (95% CI, 0.51-8.11; P = .32). Conclusion: Physeal-sparing anatomic reconstruction of the MPFL using an allograft tendon in skeletally immature patients was a safe and effective treatment for patellar instability, regardless of patellar height and trochlear dysplasia. Failure rates decreased when the MPFL reconstruction was performed concomitantly with a tibial tubercle osteotomy.