For large lesions and unstable lesions that are partially or completely detached, internal fixation is indicated to stabilize the fragment(s). Stabilization with internal fixation promotes vascular perfusion of the osteochondral lesion and stimulates bony healing through the application of a compressive force.¹,² Internal fixation of juvenile osteochondritis dissecans (JOCD) lesions has historically been performed using metallic hardware. However, recent innovations in fixation have led to the development of a number of types of bioabsorbable implants.

A recent study by Adachi et al.³ retrospectively evaluated the outcomes of 33 unstable JOCD lesions that underwent fixation using bioabsorbable pins. The authors found that after an average of 2.4 months, 32 of the 33 lesions had healed, as evidenced by plain radiographs.³ Additionally, in this study, no complications with bioabsorbable fixation instrumentation such as infection, synovitis, or inflammation were evident.

Another study conducted by Dines et al.⁴ evaluated the efficacy of bioabsorbable nails composed of poly(L-lactic acid) (PLLA) for internal fixation of JOCD lesions in nine patients. The mean postoperative Lysholm score was 94 and postoperative magnetic resonance imaging (MRI) analysis revealed that seven of the nine lesions had fully healed.

Abouassaly et al.⁵ recently published a systematic review that compared the efficacy of the different surgical techniques aimed to treat JOCD lesions. Of the 516 lesions included in the analysis, 94.1% were deemed healed postoperatively in spite of the diversity of techniques employed by the various authors included in the study. We await long-term studies to further characterize the efficacy of bioabsorbable implants in pediatric patients as they skeletally mature.

Bioabsorbable implants for fixation of JOCD lesions have specific advantages over metallic fixation. Bioabsorbable fixation does not require harvesting healthy tissue, does not interfere with MRI imaging, and may be associated with a lower incidence of hardware prominence.³ Darts and tacks are typically smaller than screws and therefore induce less damage to the articular cartilage while allowing for more points of fixation. Most importantly, the use of bioabsorbable implants does not require a second operation to remove hardware. The increasing popularity of bioabsorbable implants has also exposed important complications associated with their use. Namely, various studies have reported implant failure and development of a delayed local inflammatory synovitis weeks after implantation.⁶ Additionally, most bioabsorbable implants employ a less significant compressive force compared to metallic screws.³

At the same time, metallic fixation is also associated with certain disadvantages. The most significant disadvantage is that metallic fixation demands removal of hardware, which can be especially upsetting for pediatric patients who are active in sports and recreation. Having to undergo a second procedure further delays the time for children to return to play and function. Furthermore, Guhl⁷ reported that metallic implants are associated with pin breakage, loosening, and migration through the skin. Finally, metallic hardware
prominence resulting in damage to the opposing joint surface or screw head breakage may require additional surgical intervention.

The recent popularity of bioabsorbable fixation has spurred the development of numerous bioabsorbable implant options. The implants that are typically composed of PLLA alone include the SmartScrew, the SmartNail, the Bio-Compression Screw, and the Chondral Dart. However, other implants are copolymers between PLLA and PGA (polyglycolic acid). These include the ReUnite screw and the LactoNail. One study compared the compression forces and pullout strengths of four different bioabsorbable implants (SmartScrew, SmartNail, LactoNail, ReUnite Screw) for osteochondritis dissecans (OCD) lesion fixation using a synthetic bone model.⁸ The authors found that the SmartScrew generated the greatest compression force as well as the greatest pullout strength compared to the other three implants. See Table 25.1 for a summary of the bioabsorbable implant options.