Hunter and Willis25 retrospectively reviewed patients with tibial eminence fractures treated with either screw or suture fixation and found a 44% reoperation rate in the screw-fixation group. Removal was often recommended as a result of hardware-related issues. There was a 13% reoperation rate in the suture-fixation group, which resulted largely from stiffness.25 In a recent review, Gans and colleagues19 reviewed 6 publications comparing screw and suture fixation of tibial eminence fractures and found 82.4% of screw patients had laxity on both the anterior drawer and Lachman tests, compared with 18.8% in the suture-fixation group. This study also noted a slightly higher rate of arthrofibrosis in patients treated with suture fixation.19 Biomechanical studies indicate that suture fixation imparts greater strength under cyclic-loading conditions;26 however, there does not appear to be a difference in ultimate force required for fixation failure.27
Ultimately, both suture and screw fixation result in secure methods of fixation; however, there are often greater issues with screw fixation because of the persistent hardware. Metal has been the most popular method for fracture fixation, and while biodegradable materials have been alluring, adverse tissue reactions have slowed implementation. However, these implants have become increasingly sophisticated, thereby reducing disadvantages.28 Previous biodegradable devices were often composed of a single polymer, and many caused adverse reactions by degrading too quickly or provided no real advantages because they degraded too slowly.29 As the number of polymers approved for internal use and surgical applications continues to rise, so too will the benefits of employing this technology. Furthermore, by including multiple polymers in these implants, one is better able to control the degradation rate, limiting the tissue response.
In this study, we employed PLLA/PGA nails. Studies of PGA implants indicate this molecule degrades at a fast rate resulting in adverse tissue reactions. Adverse reactions in studies of PLLA implants are less frequent because of their slower rate of degradation.29,30 Combining these monomers results in appropriate strength and a controlled degradation rate, reducing the likelihood of adverse reactions. Furthermore, numerous studies have reported that inflammatory responses in children are rare and mild in nature.31,32 Absorbable implants have displayed efficacy in numerous orthopedic settings33-36 and are beneficial in procedures that are not suitable for repeated surgeries, such as reconstruction of the ACL.37 There is some concern about the use of absorbable implants in synovial joints. Polyglycolic acid use in synovial joints may cause foreign-body reactions and may increase the risk of intra-articular dissemination of polymeric debris;38 however, use of a multipolymer construct decreases the likelihood of this occurrence.
Polyglycolic nails confer the advantage over nonresorbable screw fixation because further procedure for hardware removal is not required. Although suture fixation has proved to be beneficial over nonresorbable screw fixation, implantation of resorbable nails appears to have several advantages. In Dr. Estes’ experience, placement of resorbable screws through an accessory superomedial portal is far less technically demanding than placement of suture through the fracture fragment. Further, as sutures are passed from the extra-articular to the intra-articular region of the joint, capsular layers of the knee may inadvertently be bound up in the fixation, predisposing to arthrofibrosis.
At the same time, biodegradable devices are often more costly than alternative forms of treatment; however, a true cost-to-benefit analysis requires consideration of other factors. One of the benefits of biodegradable hardware is that there is no need for follow-up hardware removal. Reports have indicated that up to 91% of patients thought that hardware removal was the most negative aspect of metal implants.39 It is estimated that if the removal rate for metallic implants is higher than 19% to 54%, resorbable implants would be more cost-effective.40 The cost of sutures and screws is variable, however; they are invariably less expensive than biodegradable nails. A study of fracture patients determined that biodegradable implants were cheaper on average after considering the cost of implant removal.40 Ultimately, the hardware choice depends on numerous factors, including surgeon’s discretion; however, biodegradable hardware should not be discounted for financial reasons because the difference in cost is likely negligible.
Conclusion
The approach described in this report offers efficient and secure fixation with resorbable hardware without a reduction in range of motion. Resorbable implants may prove beneficial in the treatment of tibial eminence fractures by offering robust fixation without the concerns associated with permanent hardware.