**5. Postoperative evaluation**

Postoperative evaluation is also possible and provides useful clinical feedback. Improvement in the maximum internal rotation angle indicates a release from the bony impingement. Ross et al. also adopted computer simulation analysis to evaluate the three-dimensional morphology of hips with residual symptoms prior to revision FAI surgery [5].

Another application of postoperative evaluation after osteochondroplasty is the assessment of mechanical bone strength by finite element analysis. This approach was used by Oba et al. to calculate changes in simulated fracture load between pre- and postoperative femur models in a clinical study of postoperative

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*The Practice of Computer-Assisted Planning and Navigation for Hip Arthroscopy*

FAI subjects [8]. The results suggested that the bone resection depth measured at the head-neck junction and transcervical reference plane correlates with fracture risk after osteochondroplasty. By contrast, bone resection at more proximal areas did not have a significant influence on the postoperative femur model strength [8]. Similarly, Alonso-Rasgado et al. concluded that resection depth should be kept to <10 mm or 1/3 of the diameter of the neck based on their finite element study [9]. These clinical implications provide valuable feedback to improve the preoperative

There are several important limitations in the methodology of computer simulation. First, the bone model used in the simulation does not assess factors related to the soft tissue, including the labrum. Therefore, impingement simulation that includes consideration of the soft tissues may be required. Secondly, the simulation conditions, i.e., the variation of flexion angle, have not yet been fully established. In addition, the influence of pelvic tilt must be considered, as dynamic changes significantly influence the impingement location and simulated range of motion [10]. Currently, we use the functional pelvic plane as the reference plane; however, pelvic tilt would certainly be influenced by interventions, such as rehabilitation or

A summary of the preoperative assessment, planning, and navigation for arthroscopic FAI surgery using computer-assisted technology is presented. Each step of computer-assisted technology is mutually related, and it is important to comprehend this technology as a sequential flow. Although there are several limitations that need to be addressed, the notable benefits can contribute to the successful

The authors gratefully acknowledge Takayuki Oisi, Msastoshi Oba, and So

*DOI: http://dx.doi.org/10.5772/intechopen.89502*

planning of future cases (**Figure 1**).

surgery [11].

**7. Conclusion**

treatment of FAI.

**Acknowledgements**

**Conflict of interest**

Kubota for contributing related study projects.

Reprinted from [7] with permission from Elsevier.

The authors have no conflict of interest to declare.

**6. Limitations and future prospects**

*The Practice of Computer-Assisted Planning and Navigation for Hip Arthroscopy DOI: http://dx.doi.org/10.5772/intechopen.89502*

FAI subjects [8]. The results suggested that the bone resection depth measured at the head-neck junction and transcervical reference plane correlates with fracture risk after osteochondroplasty. By contrast, bone resection at more proximal areas did not have a significant influence on the postoperative femur model strength [8]. Similarly, Alonso-Rasgado et al. concluded that resection depth should be kept to <10 mm or 1/3 of the diameter of the neck based on their finite element study [9]. These clinical implications provide valuable feedback to improve the preoperative planning of future cases (**Figure 1**).
