ACL Size, but Not Signal Intensity, Is Influenced by Sex, Body Size, and Knee Anatomy

The metabolome of male and female individuals with knee osteoarthritis is influenced by 18-months of weight loss intervention: the IDEA trial

BACKGROUND

The Intensive Diet and Exercise for Arthritis (IDEA) trial was a randomized trial conducted to evaluate the effects of diet and exercise on osteoarthritis (OA), the most prevalent form of arthritis. Various risk factors, including obesity and sex, contribute to OA's debilitating nature. While diet and exercise are known to improve OA symptoms, cellular and molecular mechanisms underlying these interventions, as well as effects of participant sex, remain elusive.

METHODS

Serum was obtained at three timepoints from IDEA participants assigned to groups of diet, exercise, or combined diet and exercise (n = 10 per group). A randomly selected subset of serum samples were extracted and analyzed via liquid chromatography-mass spectrometry combined with metabolomic profiling to unveil mechanisms associated with types of intervention and disease. Extracted serum was pooled and fragmentation patterns were analyzed to identify metabolites that statistically differentially regulated between groups.

RESULTS

Changes in metabolism across male and female IDEA participants after 18-months of diet, exercise, and combined diet and exercise intervention mapped to lipid, amino acid, carbohydrate, vitamin, and matrix metabolism. The diverse metabolic landscape detected across IDEA participants shows that intervention type differentially impacts the serum metabolome of OA individuals. Moreover, dissimilarities in the serum metabolome corresponded with participant sex.

CONCLUSIONS

These findings suggest that intensive weight loss among males and females offers potential metabolic benefits for individuals with knee OA. This study provides a deeper understanding of dysregulation occurring during OA development in parallel with various interventions, potentially paving the way for improved interventions, treatments, and quality of life of those impacted by OA.

TRIAL REGISTRATION

clinicaltrials.gov Identifier NCT00381290, Registered, 9/25/2006.

The metabolome of individuals with knee osteoarthritis is influenced by 18-months of an exercise and weight loss intervention and sex: the IDEA trial

Objective

The Intensive Diet and Exercise for Arthritis (IDEA) trial was conducted to evaluate the effects of diet and exercise on osteoarthritis (OA), the most prevalent form of arthritis. Various risk factors, such as obesity and sex, contribute to the debilitating nature of OA. While diet and exercise are known to improve OA symptoms, cellular and molecular mechanisms underlying these interventions, as well as effects of participant sex, remain elusive.

Methods

Serum was obtained at three timepoints from IDEA participants assigned to groups of diet, exercise, or combined diet and exercise (n=10 per group). All serum metabolites were extracted and analyzed via liquid chromatography-mass spectrometry combined with metabolomic profiling. Extracted serum was pooled and fragmentation patterns were analyzed to identify metabolites that statistically differentially regulated between groups.

Results

Changes in metabolism across male and female IDEA participants after 18-months of diet, exercise, and combined diet and excise intervention mapped to lipid, amino acid, carbohydrate, vitamin, and matrix metabolism. The diverse metabolic landscape detected across IDEA participants shows that intervention type impacts the serum metabolome of individuals with OA in distinct patterns. Moreover, differences in the serum metabolome corresponded with participant sex.

Conclusions

These findings suggest that intensive weight loss among male and female subjects offers potential metabolic benefits for individuals with knee OA. This provides a deeper understanding of dysregulation occurring during OA development that may pave the way for improved interventions, treatments, and quality of life of those impacted by this disease.

Cyclic loading induces anabolic gene expression in ACLs in a load-dependent and sex-specific manner

Anterior cruciate ligament (ACL) injuries are historically thought to be a result of a single acute overload or traumatic event. However, recent studies suggest that ACL failure may be a consequence of fatigue damage. Additionally, the remodeling response of ACLs to fatigue loading is unknown. Therefore, the objective of this study was to investigate the remodeling response of ACLs to cyclic loading. Furthermore, given that women have an increased rate of ACL rupture, we investigated whether this remodeling response is sex specific. ACLs were harvested from male and female New Zealand white rabbits and cyclically loaded in a tensile bioreactor mimicking the full range of physiological loading (2, 4, and 8 MPa). Expression of markers for anabolic and catabolic tissue remodeling, as well as inflammatory cytokines, was quantified using quantitative reverse transcription polymerase chain reaction. We found that the expression of markers for tissue remodeling of the ACL is dependent on the magnitude of loading and is sex specific. Male ACLs activated an anabolic response to cyclic loading at 4 MPa but turned off remodeling at 8 MPa. These data support the hypothesis that noncontact ACL injury may be a consequence of failed tissue remodeling and inadequate repair of microtrauma resulting from elevated loading. Compared to males, female ACLs failed to increase anabolic gene expression with loading and exhibited higher expression of catabolic genes at all loading levels, which may explain the increased rate of ACL tears in women. Together, these data provide insight into load-induced ACL remodeling and potential causes of tissue rupture.

Intercondylar notch width and osteophyte width impact meniscal healing and clinical outcomes following transtibial pullout repair of medial meniscus posterior root tears

PURPOSE

This retrospective study aimed to investigate the relationship between intercondylar notch width (ICNW), osteophyte width (OW), and the healing of medial meniscus posterior root tears (MMPRTs) following arthroscopic pullout repair.

METHODS

The study included 155 patients diagnosed with MMPRTs who underwent transtibial pullout repair. Meniscal healing status was evaluated on second-look arthroscopy using a previously reported meniscus healing score. Patients were divided into two groups based on this score: the high healing score (group HH, healing score ≥ 8 points) and suboptimal healing score (group SO, healing score ≤ 6 points) groups. Computed tomography scans were performed on patients 1 week postsurgery. ICNW and OW widths were measured and relatively evaluated based on their ratio to the intercondylar distance (ICD), represented as the ICNW/ICD ratio (%) and OW/ICD ratio (%), respectively. Patient-reported outcomes were assessed preoperatively and on second-look arthroscopy using the Knee injury and Osteoarthritis Outcome Score (KOOS) and visual analogue scale (VAS).

RESULTS

There were no significant demographic differences between the SO and HH group (n = 35 and 120 patients, respectively). Regarding radiographic measurements, significant differences were observed in the ICNW/ICD ratio (group SO, 24.2%; group HH, 25.2%; p = 0.024), OW (group SO, 2.6 mm; group HH, 2.0 mm; p < 0.001), and OW/ICD ratio (group SO, 3.5%; group HH, 2.7%; p < 0.001). Both groups had similar preoperative clinical scores, but postoperative clinical scores, including KOOS-activities of daily living (group SO, 83.4; group HH, 88.7; p = 0.035) and VAS (group SO, 19.1; group HH, 11.3; p = 0.005), were significantly better in group HH.

CONCLUSION

The study suggests that ICNW and OW may play a crucial role in MMPRT healing following arthroscopic pullout repair, as evidenced by the worse clinical outcomes associated with a narrower ICNW and wider OW. These findings highlight the potential significance of ICNW and OW assessments when evaluating meniscal repair indications.

LEVEL OF EVIDENCE

Level III.

A Surgical Technique for Anterior Cruciate Ligament Reconstruction Using Semitendinosus Graft: An All-Inside Transfemoral Approach

Given the paucity of reports on all-inside reconstruction procedures via the transfemoral approach, we describe a minimally invasive, all-inside transfemoral technique that enables creating femoral and tibial sockets from the intra-articular cavity. Our transfemoral approach makes it possible to sequentially create femoral and tibial sockets using the same reamer bit, while a single drilling guide is set in place. Our custom socket drilling guide was designed to integrate with a tibial tunnel guide, which helped locate the tunnel exit at an anatomically acceptable location. The advantages of this method include easy and precise positioning of the femoral tunnel, narrow tibial tunnel, minimal damage to the intramedullary trabecular bone integrity, and low postoperative risks of pain, bleeding, and infections.

Three-dimensional magnetic resonance imaging analysis shows sex-specific patterns in changes in anterior cruciate ligament cross-sectional area along its length

Smaller anterior cruciate ligament (ACL) size in females has been hypothesized to be a key contributor to a higher incidence of ACL tears in that population, as a lower cross-sectional area (CSA) directly corresponds to a larger stress on the ligament for a given load. Prior studies have used a mid-length CSA measurement to quantify ACL size. In this study, we used magnetic resonance imaging to quantify the CSA along the entire length of the intact ACL. We hypothesized that changes in the ACL CSA along its length would have different patterns in males and females. We also hypothesized that changes in ACL CSA along its length would be associated with body size or knee size with different associations in females and males. MR images of contralateral ACL-intact knees of 108 patients (62 females, 13-35 years) undergoing ACL surgery were used to measure the CSA along the ACL length, using a custom program. For both females and males, the largest CSA was located at 37%-39% of ACL length from the tibial insertion. Compared to females, males had a significantly larger CSA only within the distal 41% of the ACL (p < 0.001). ACL CSA was associated with patient height and weight in males (r > 0.3; p < 0.05), whereas it was associated with intercondylar notch width in females (r > 0.3; p < 0.05). These findings highlight the importance of standardizing the location of measurement of ACL CSA.