The Prognosis of Arthrofibroses: Prevalence, Clinical Shortcomings, and Future Prospects

Shoulder Adhesive Capsulitis Prior to Total Knee Arthroplasty is Associated With Increased Rates of Postoperative Stiffness Requiring Manipulation Under Anesthesia and Arthroscopic Lysis of Adhesions

BACKGROUND

Arthrofibrosis following total knee arthroplasty (TKA) and adhesive capsulitis (AC) of the shoulder develop via a similar pathologic process. The purpose of this study was to examine the relationship between these two conditions.

METHODS

This was a retrospective cohort study using a large nationwide claims database. Patients who had a history of shoulder AC prior to TKA were compared to TKA patients who did not have AC history comparing rates of postoperative stiffness, manipulation under anesthesia (MUA), arthroscopic lysis of adhesions (LOAs), and revision arthroplasty at postoperative timepoints (3 months, 6 months, 1 year, and 2 years).

RESULTS

Within 3 months, 6 months, 1 year, and 2 years of their TKAs, patients who had a history of AC prior to TKA were significantly more likely to experience stiffness (OR [odds ratio] = 1.29, 1.28, 1.32, and 1.36, respectively) and LOAs (OR = 6.78, 3.65, 2.99, and 2.81, respectively). They also showed increased risk of MUA within 6 months, 1 year, and 2 years (OR = 1.15, 1.15, and 1.16, respectively) of their TKAs. Patients having a preoperative diagnosis of AC did not have an increased risk of undergoing revision surgery 1 year or 2 years after their TKAs (P > .05).

CONCLUSIONS

Patients diagnosed with AC prior to TKA experience higher rates of postoperative stiffness, resulting in additional interventions such as MUA and LOAs. These findings identify a particularly high-risk patient population that may benefit from additional interventions prior to and following TKA.

LEVEL OF EVIDENCE

This is a level III prognostic study.

Genetic causal association between frozen shoulder and carpal tunnel syndrome: a two-sample mendelian randomization

OBJECTIVE

Observational studies have suggested an association between frozen shoulder (FS) and carpal tunnel syndrome (CTS). However, due to challenges in establishing a temporal sequence, the causal relationship between these two conditions remains elusive. This study, based on aggregated data from large-scale population-wide genome-wide association studies (GWAS), investigates the genetic causality between FS and CTS.

METHODS

Initially, a series of quality control measures were employed to select single nucleotide polymorphisms (SNPs) closely associated with the exposure factors. Two-sample Mendelian randomization (MR) was utilized to examine the genetic causality between FS and CTS, employing methods including Inverse-Variance Weighted (IVW), MR-Egger, Weighted Median, Simple Mode, and Weighted Mode approaches. Subsequently, sensitivity analyses were conducted to assess the robustness of the MR analysis results.

RESULTS

IVW analysis results indicate a positive causal relationship between CTS and FS (p < 0.05, OR > 1), while a negative causal relationship between the two conditions was not observed. Heterogeneity tests suggest minimal heterogeneity in our IVW analysis results (p > 0.05). Multivariable MR testing also indicates no pleiotropy in our IVW analysis (p > 0.05), and stepwise exclusion tests demonstrate the reliability and stability of the MR analysis results. Gene Ontology (GO) pathway analysis reveals enrichment of genes regulated by the associated SNPs in the TGFβ-related pathways.

CONCLUSION

This study provides evidence of the genetic causal association between frozen shoulder and carpal tunnel syndrome and provides new insights into the genetics of fibrotic disorders.

Minimally invasive, sustained-release relaxin-2 microparticles reverse arthrofibrosis

Substantial advances in biotherapeutics are distinctly lacking for musculoskeletal diseases. Musculoskeletal diseases are biomechanically complex and localized, highlighting the need for novel therapies capable of addressing these issues. All frontline treatment options for arthrofibrosis, a debilitating musculoskeletal disease, fail to treat the disease etiology-the accumulation of fibrotic tissue within the joint space. For millions of patients each year, the lack of modern and effective treatment options necessitates surgery in an attempt to regain joint range of motion (ROM) and escape prolonged pain. Human relaxin-2 (RLX), an endogenous peptide hormone with antifibrotic and antifibrogenic activity, is a promising biotherapeutic candidate for musculoskeletal fibrosis. However, RLX has previously faltered through multiple clinical programs because of pharmacokinetic barriers. Here, we describe the design and in vitro characterization of a tailored drug delivery system for the sustained release of RLX. Drug-loaded, polymeric microparticles released RLX over a multiweek time frame without altering peptide structure or bioactivity. In vivo, intraarticular administration of microparticles in rats resulted in prolonged, localized concentrations of RLX with reduced systemic drug exposure. Furthermore, a single injection of RLX-loaded microparticles restored joint ROM and architecture in an atraumatic rat model of arthrofibrosis with clinically derived end points. Finally, confirmation of RLX receptor expression, RXFP1, in multiple human tissues relevant to arthrofibrosis suggests the clinical translational potential of RLX when administered in a sustained and targeted manner.

Management of arthrofibrosis in neuromuscular disorders: a review

Arthrofibrosis, or rigid contracture of major articular joints, is a significant morbidity of many neurodegenerative disorders. The pathogenesis depends on the mechanism and severity of the precipitating neuromuscular disorder. Most neuromuscular disorders, whether spastic or hypotonic, culminate in decreased joint range of motion. Limited range of motion precipitates a cascade of pathophysiological changes in the muscle-tendon unit, the joint capsule, and the articular cartilage. Resulting joint contractures limit functional mobility, posing both physical and psychosocial burdens to patients, economic burdens on the healthcare system, and lost productivity to society. This article reviews the pathophysiology of arthrofibrosis in the setting of neuromuscular disorders. We describe current non-surgical and surgical interventions for treating arthrofibrosis of commonly affected joints. In addition, we preview several promising modalities under development to ameliorate arthrofibrosis non-surgically and discuss limitations in the field of arthrofibrosis secondary to neuromuscular disorders.