Faculty Bibliography

BACKGROUND:Optimal characterization of Adult acquired flatfoot deformity (AAFD) on two-dimensional radiograph can be challenging. Weightbearing Cone Beam CT (CBCT) may improve characterization of the three-dimensional (3D) structural details of such dynamic deformity. We compared and validated AAFD measurements between weightbearing radiograph and weightbearing CBCT images. METHODS:20 patients (20 feet, right/left: 15/5, male/female: 12/8, mean age: 52.2) with clinical diagnosis of flexible AAFD were prospectively recruited and underwent weightbearing dorsoplantar (DP) and lateral radiograph as well as weightbearing CBCT. Two foot and ankle surgeons performed AAFD measurements at parasagittal and axial planes (lateral and DP radiographs, respectively). Intra- and Inter-observer reliabilities were calculated by Intraclass correlation (ICC) and Cohen's kappa. Mean values of weightbearing radiograph and weightbearing CBCT measurements were also compared. RESULTS:Except for medial-cuneiform-first-metatarsal-angle, adequate intra-observer reliability (range:0.61-0.96) was observed for weightbearing radiographic measurements. Moderate to very good interobserver reliability between weightbearing radiograph and weightbearing CBCT measurements were observed for the following measurements: Naviculocuneiform-angle (ICC:0.47), Medial-cuneiform-first-metatarsal-gapping (ICC:0.58), cuboid-to-floor-distance (ICC:0.68), calcaneal-inclination-angle(ICC:0.7), axial Talonavicular-coverage-angle(ICC:0.56), axial Talus-first-metatarsal-angle(ICC:0.62). Comparing weightbearing radiograph and weightbearing CBCT images, statistically significant differences in the mean values of parasagittal talus-first-metatarsal-angle, medial-cuneiform-first-metatarsal-angle, medial-cuneiform-to-floor-distance and navicular-to-floor-distance was observed (P < 0.05). CONCLUSION/CONCLUSIONS:Moderate to very good correlation was observed between certain weightbearing radiograph and weightbearing CBCT measurements, however, significant difference was observed between a number of AAFD measurements, which suggest that 2D radiographic evaluation could potentially underestimate the severity of AAFD, when compared to 3D weightbearing CT assessment.

RECOMMENDATION/UNASSIGNED:to describe this same deformity (see Introduction section with nomenclature). Correction of this deformity is important to restore the weightbearing tripod of the foot and help resist a recurrence of foot collapse. When the forefoot varus deformity is isolated to the medial metatarsal and medial cuneiform, correction is indicated with an opening wedge medial cuneiform (Cotton) osteotomy, typically with interposition of an allograft bone wedge from 5 to 11 mm in width at the base. When the forefoot varus is global, involving varus angulation of the entire forefoot and midfoot relative to the hindfoot, other procedures are needed to adequately correct the deformity. LEVEL OF EVIDENCE/UNASSIGNED:Level V, consensus, expert opinion.

RECOMMENDATION/UNASSIGNED:There is evidence indicating that the amount of bony correction performed in the setting of progressive collapsing foot deformity reconstructive surgery can be titrated within a recommended range for a variety of procedures. The typical range when performing a medial displacement calcaneal osteotomy should be 7 to 15 mm of medialization of the tuberosity. The typical range when performing an Evans lateral column lengthening should be 5 to 10 mm of a laterally based wedge in the anterior calcaneus. The typical range when performing a plantarflexion opening wedge osteotomy of the medial cuneiform (Cotton) osteotomy should be 5 to 10 mm of a dorsal wedge. LEVEL OF EVIDENCE/UNASSIGNED:Level V, consensus, expert opinion.

RECOMMENDATION/UNASSIGNED:The historical nomenclature for the adult acquired flatfoot deformity (AAFD) is confusing, at times called posterior tibial tendon dysfunction (PTTD), the adult flexible flatfoot deformity, posterior tibial tendon rupture, peritalar instability and peritalar subluxation (PTS), and progressive talipes equinovalgus. Many but not all of these deformities are associated with a rupture of the posterior tibial tendon (PTT), and some of these are associated with deformities either primarily or secondarily in the midfoot or ankle. There is similar inconsistency with the use of classification schemata for these deformities, and from the first introduced by Johnson and Strom (1989), and then modified by Myerson (1997), there have been many attempts to provide a more comprehensive classification system. However, although these newer more complete classification systems have addressed some of the anatomic variations of deformities encountered, none of the above have ever been validated. The proposed system better incorporates the most recent data and understanding of the condition and better allows for standardization of reporting. In light of this information, the consensus group proposes the adoption of the nomenclature "Progressive Collapsing Foot Deformity" (PCFD) and a new classification system aiming at summarizing recent data published on the subject and to standardize data reporting regarding this complex 3-dimensional deformity. LEVEL OF EVIDENCE/UNASSIGNED:Level V, consensus, expert opinion. CONSENSUS STATEMENTS VOTED/UNASSIGNED:A new classification system is proposed and should be used to stage the deformity clinically and to define treatment.Delegate vote: agree, 89% (8/9); abstain, 11% (1/9).(Strong consensus).

RECOMMENDATION/UNASSIGNED:There is evidence supporting medial soft tissue reconstruction, such as spring and deltoid ligament reconstructions, in the treatment of severe progressive collapsing foot deformity (PCFD). We recommend spring ligament reconstruction to be considered in addition to lateral column lengthening or subtalar fusion at the initial operation when those procedures have given at least 50% correction but inadequate correction of the severe flexible subluxation of the talonavicular and subtalar joints. We also recommend combined flatfoot reconstruction and deltoid reconstruction be considered as a joint sparing alternative in the presence of PCFD with valgus deformity of the ankle joint if there is 50% or more of the lateral joint space remaining. LEVEL OF EVIDENCE/UNASSIGNED:Level V, expert opinion.

RECOMMENDATION/UNASSIGNED:Peritalar subluxation represents an important hindfoot component of progressive collapsing foot deformity, which can be associated with a breakdown of the medial longitudinal arch. It results in a complex 3-dimensional deformity with varying degrees of hindfoot valgus, forefoot abduction, and pronation. Loss of peritalar stability allows the talus to rotate and translate on the calcaneal and navicular bone surfaces, typically moving medially and anteriorly, which may result in sinus tarsi and subfibular impingement. The onset of degenerative disease can manifest with stiffening of the subtalar (ST) joint and subsequent fixed and possibly arthritic deformity. While ST joint fusion may permit repositioning and stabilization of the talus on top of the calcaneus, it may not fully correct forefoot abduction and it does not correct forefoot varus. Such varus may be addressed by a talonavicular (TN) fusion or a plantar flexion osteotomy of the first ray, but, if too pronounced, it may be more effectively corrected with a naviculocuneiform (NC) fusion. The NC joint has a curvature in the sagittal plane. Thus, preserving the shape of the joint is the key to permitting plantarflexion correction by rotating the midfoot along the debrided surfaces and to fix it. Intraoperatively, care must be also taken to not overcorrect the talocalcaneal angle in the horizontal plane during the ST fusion (eg, to exceed the external rotation of the talus and inadvertently put the midfoot in a supinated position). Such overcorrection can lead to lateral column overload with persistent lateral midfoot pain and discomfort. A contraindication for an isolated ST fusion may be a rupture of posterior tibial tendon because of the resultant loss of the internal rotation force at the TN joint. In these cases, a flexor digitorum longus tendon transfer is added to the procedure. LEVEL OF EVIDENCE/UNASSIGNED:Level V, consensus, expert opinion.

RECOMMENDATION/UNASSIGNED:Progressive collapsing foot deformity (PCFD) is a complex 3D deformity with varying degrees of hindfoot valgus, forefoot abduction, and midfoot supination. Although a medial displacement calcaneal osteotomy can correct heel valgus, it has far less ability to correct forefoot abduction. More severe forefoot abduction, most frequently measured preoperatively by assessing talonavicular coverage on an anteroposterior (AP) weightbearing conventional radiographic view of the foot, can be more effectively corrected with a lateral column lengthening procedure than by other osteotomies in the foot. Care must be taken intraoperatively to not overcorrect the deformity by restricting passive eversion of the subtalar joint or causing adduction at the talonavicular joint on simulated AP weightbearing fluoroscopic imaging. Overcorrection can lead to lateral column overload with persistent lateral midfoot pain. The typical amount of lengthening of the lateral column is between 5 and 10 mm. LEVEL OF EVIDENCE/UNASSIGNED:Level V, consensus, expert opinion. CONSENSUS STATEMENT ONE/UNASSIGNED:Lateral column lengthening (LCL) procedure is recommended when the amount of talonavicular joint uncoverage is above 40%. The amount of lengthening needed in the lateral column should be judged intraoperatively by the amount of correction of the uncoverage and by adequate residual passive eversion range of motion of the subtalar joint.Delegate vote: agree, 78% (7/9); disagree, 11% (1/9); abstain, 11% (1/9).(Strong consensus). CONSENSUS STATEMENT TWO/UNASSIGNED:When titrating the amount of correction of abduction deformity intraoperatively, the presence of adduction at the talonavicular joint on simulated weightbearing fluoroscopic imaging is an important sign of hypercorrection and higher risk for lateral column overload.Delegate vote: agree, 100% (9/9); disagree, 0%; abstain, 0%.(Unanimous, strongest consensus). CONSENSUS STATEMENT THREE/UNASSIGNED:The typical range for performing a lateral column lengthening is between 5 and 10 mm to achieve an adequate amount of talonavicular coverage.Delegate vote: agree, 100% (9/9); disagree, 0%; abstain, 0%.(Unanimous, strongest consensus).

RECOMMENDATION/UNASSIGNED:In the treatment of progressive collapsing foot deformity (PCFD), the combination of bone shape, soft tissue failure, and host factors create a complex algorithm that may confound choices for operative treatment. Realignment and balancing are primary goals. There was consensus that preservation of joint motion is preferred when possible. This choice needs to be balanced with the need for performing joint-sacrificing procedures such as fusions to obtain and maintain correction. In addition, a patient's age and health status such as body mass index is important to consider. Although preservation of motion is important, it is secondary to a stable and properly aligned foot. LEVEL OF EVIDENCE/UNASSIGNED:Level V, consensus, expert opinion.

RECOMMENDATION/UNASSIGNED:CT is obtained, important findings to be assessed are sinus tarsi impingement, subfibular impingement, increased valgus inclination of the posterior facet of the subtalar joint, and subluxation of the subtalar joint at the posterior and/or middle facet. LEVEL OF EVIDENCE/UNASSIGNED:Level V, consensus, expert opinion.

BACKGROUND:Identifying preoperative patient characteristics that correlate with an increased risk of periprosthetic joint infection (PJI) following total ankle replacement (TAR) is of great interest to orthopaedic surgeons, as this may assist with appropriate patient selection. The purpose of this study is to systematically review the literature to identify risk factors that are associated with PJI following TAR. METHODS:Utilizing the terms "(risk factor OR risk OR risks) AND (infection OR infected) AND (ankle replacement OR ankle arthroplasty)" we searched the PubMed/MEDLINE electronic databases. The quality of the included studies was then assessed using the AAOS Clinical Practice Guideline and Systematic Review Methodology. Recommendations were made using the overall strength of evidence. RESULTS:Eight studies met the inclusion criteria. A limited strength of recommendation can be made that the following preoperative patient characteristics correlate with an increased risk of PJI following TAR: inflammatory arthritis, prior ankle surgery, age less than 65 years, body mass index less than 19, peripheral vascular disease, chronic lung disease, hypothyroidism, and low preoperative AOFAS hindfoot scores. There is conflicting evidence in the literature regarding the effect of obesity, tobacco use, diabetes, and duration of surgery. CONCLUSIONS:Several risk factors were identified as having an association with PJI following TAR. These factors may alert surgeons that a higher rate of PJI is possible. However, because of the low level of evidence of reported studies, only a limited strength of recommendation can be ascribed to regard these as risk factors for PJI at this time.