Key Points

 Preoperative planning and critical postoperative evaluation are crucial

 Implant selection (type and quality) is paramount

 Prevention trumps revision; therefore, honing surgical skills and CE are essential

 The true costs of revision are financial, biological, and personal reputation

Revisions of osteosyntheses are relatively uncommon complications and are most frequently associated with bone and/or implant failure. Yet the need for revision may also stem from iatrogenic complications such as poor reduction with secondary malalignment or infections. Regardless, the common denominator of failures is technical error on the part of the surgeon. Multiple factors may be involved, eventually leading to postoperative failure requiring revision. Such factors may include inaccurate diagnosis related to poor imaging techniques, cursory preoperative planning, improper implant selection, failure to adhere to basic surgical principles, inaccurate postoperative evaluation, or misevaluation of postoperative compliance.

Preoperative Imaging and Planning

Radiographs and/or advanced imaging that includes CT scans or MRI are the primary tools employed for fracture repair planning. High-quality orthogonal and on occasion special projections of both the operated limb and contralateral limb should be performed. Inclusion of a calibration marker in every radiograph is paramount to adequate planning with dedicated orthopaedic software (i.e., OrthoView, Mimics, etc.). These powerful tools can then be used to assist the surgeon with the best implant choice and revision strategy. It is important to keep in mind that the benefits of prevention outweigh the costs of revision, not only to the patient biologically and owner/hospital financially, but to our reputation as surgeons. With appropriate preoperative planning strategies and knowledge, revisions can be avoided. "He who fails to plan is planning to fail." - Sir Winston Churchill

Implant Selection

Improper implant selection may come from inadequate planning, misunderstanding of fracture and implant biomechanics, and lack of diverse implant availability. The net result is often the inability of the implant to effectively counteract disruptive forces at the fracture site. Of these, shear forces are the most deleterious to bone healing while cyclic bending moments affect the fatigue life of the implant itself. In the current competitive market, one should keep in mind that the quality of an implant in terms of both design and material greatly affects its mechanical performance. Extensively tested implants offer reliable results when used appropriately. Suitable implant selection should allow for immediately stable osteosynthesis, which in turn should promote early functional recovery without the need for additional external splinting.

Adherence to Basic and Advanced Surgical Principles

Such principles include:

1.  Comprehensive knowledge of locoregional anatomy as well as least-invasive surgical approaches

2.  In-depth understanding of the benefits and limitations of time-tested (open reduction and internal fixation [ORIF] and open but do not touch [OBDNT]) as well as new surgical techniques such as minimally invasive osteosynthesis (MIO)

3.  Gentle manipulation of the soft tissue envelope (including the fracture hematoma) surrounding the fracture site

4.  Strict adherence to the Halstead principles

Similarly, an inclusive command of the rules of applications of specific implants is of paramount importance to the success of any osteosynthesis.

Postoperative Evaluation

The ability to critically evaluate postoperative radiographs and patient limb function can reduce chances for failure. Radiographs should be assessed for implant positioning and fixation, limb alignment (in sagittal and transverse planes), and fracture reconstruction (particularly with articular fractures). If any of these are deemed unacceptable, immediate revision should be considered. Objective evaluation is also essential to self-improvement and honing one's surgical skills as well as accurate assessment of biomechanical principles that may help anticipate repair (implant and/or bone) failure. In most cases, the potential cause of failure can be seen during thorough and critical evaluation of postoperative radiographs. Failure to identify surgical mistakes on these radiographs may lead to failure, particularly if the surgeon is unable to adjust postoperative recommendations accordingly.

Determining the Cause of the Failure

Whether failure results from mechanical or biological factors, identifying its origin is also essential to revision planning. As with any surgical procedure, both primary and secondary revision options should be considered. Planning strategies can be reinforced with knowledge gained from continuing education courses sponsored by private companies and/or CE entities, such as the AO Foundation. As an example, from a mechanical standpoint, fatigue implant failure due to cyclic loading may be addressed with replacement of a fractured plate by an interlocking nail or choice of a larger plate. Conversely, repair failure via screw pullout from a weak, immature bone suggests that the implant is excessively stiff. In such a case, revision using a more compliant plate, a technique known as elastic plate osteosynthesis (EPO) is warranted. From a biological perspective, the surgeon must keep in mind that a revision almost invariably carries higher soft-tissue morbidity than a well-planned and performed primary osteosynthesis. Iatrogenic soft-tissue injuries generated during revision surgery (e.g., soft-tissue dissection with ORIF) create a poor environment for healing, which in turn may increase the risk of implant fatigue failure due to delayed union. With this in mind, following MIO principles is advisable during revisions.

_______

The impetus behind the development of MIO principles and techniques is in large part due to the recognition and identification of the shortcomings of ORIF with anatomical reconstruction and rigid fixation using conventional plating. As with any evolutionary step in medicine, however, the critical evaluation of a new standard of care will inevitably lead to the documentation of different boundaries intrinsic to this novel approach. Our incentive to continue to progress is the hope that these new limits will be associated with lower morbidity, better functional outcomes, and complications easier to manage when they do occur.

References

1.  Gawande A. The Checklist Manifesto: How to Get Things Right.

2.  Gawande A. Complications: A Surgeon's Notes on an Imperfect Science.

3.  Gawande A. Better: A Surgeon's Notes on Performance.

4.  Johnson AL, Houlton JEF, Vannini R. AO Principles of Fracture Management in the Dog and Cat. Stuttgart, Germany: Georg Thieme Verlag; 2005.

5.  Weller S. Instability of osteosynthesis and disturbed fracture healing. Vet Comp Ortho Traumatol. 1989;3:92–97.