Hallux rigidus is the most common arthritic condition affecting the first metatarsophalangeal (MTP) joint, leading to stiffness, pain, and limited range of motion (ROM). This condition becomes particularly debilitating as it progresses, impacting daily activities and overall quality of life. Traditionally, the gold standard treatment for advanced hallux rigidus has been arthrodesis (joint fusion), but this method restricts joint motion. Recently, there has been a growing interest in synthetic cartilage implants, such as the Cartiva implant, which aim to preserve joint function while alleviating pain.
What is the Cartiva Implant?
The Cartiva Synthetic Cartilage Implant (SCI) is a polyvinyl alcohol (PVA)-based device designed to mimic the properties of healthy cartilage. Unlike traditional metal or silastic implants, the Cartiva SCI offers a joint-sparing solution that aims to reduce pain while maintaining the natural function and biomechanics of the first MTP joint. Since its FDA approval in 2016, it has been used in over 4,000 cases globally for the treatment of hallux rigidus, offering a promising alternative to arthrodesis.
Procedure Overview
The procedure to insert a Cartiva SCI involves a dorsal approach to the first metatarsal head. The osteophytes (bone spurs) are removed, and the joint space is prepared for the implant. The Cartiva implant is then inserted, where it sits slightly proud to recreate the natural joint space. The goal is to reduce symptoms while allowing continued motion at the MTP joint.
Mid-Term Efficacy
The effectiveness of the Cartiva SCI has been assessed through various studies, including a long-term cohort study which followed patients for up to five years. Key findings include:
- Pain Reduction: Significant improvement in pain scores was observed postoperatively, with patients reporting a reduction in pain that remained stable over the medium term.
- Functionality: Both the Manchester-Oxford Foot Questionnaire (MOXFQ) and Foot and Ankle Ability Measure (FAAM) scores showed significant improvement in function, particularly in activities of daily living (ADL). These improvements were maintained at five years, although there was a slight decrease in patient satisfaction from 89% to 68% over time.
- Survival Rate: The survival rate of the Cartiva implant was observed to be 82% at five years, which is better than expected. However, some patients did experience a deterioration in function and pain relief over time, indicating that some patients may eventually require revision surgery.
Sex and Patient Factors
A notable finding from the study was that females tended to show a greater improvement in function and pain relief compared to males. This discrepancy may be related to differences in joint reaction forces or other biomechanical factors. However, no significant predictors of failure were identified in relation to age, arthritis severity, or the side of the foot operated on.
Comparison with Other Treatments
The Cartiva SCI is often compared to traditional procedures like arthrodesis, which provides reliable pain relief but at the cost of joint motion. In a study comparing these two treatments, the Cartiva SCI showed comparable outcomes in terms of pain relief and function while preserving joint movement, making it an attractive option for patients who wish to maintain mobility.
Benefits of the Cartiva SCI
- Minimally invasive: The Cartiva procedure is less invasive than arthrodesis, with a shorter recovery time.
- Joint preservation: The implant preserves joint motion, which is crucial for overall foot function.
- Improved patient satisfaction: While satisfaction declines slightly over time, many patients report lasting relief from pain and increased functionality.
Risks and Considerations
As with any surgical procedure, there are risks associated with the Cartiva SCI, including infection, implant failure, and the potential need for revision surgery. While the failure rate is relatively low, it is essential for patients to be fully informed and undergo careful selection to maximize the likelihood of a successful outcome.
Conclusion
The Cartiva Synthetic Cartilage Implant offers a promising solution for patients with hallux rigidus who want to avoid joint fusion and maintain mobility. With positive mid-term results, it represents a viable option for those looking for an effective, motion-sparing treatment. However, continued research and longer-term follow-up are necessary to fully understand its long-term durability and survival.
