Foot Deformity Correction Planning in the Sagittal Plane Based on the Vitruvian Foot First Metatarsal Anatomic Axis

The aim of this study was to test a novel planning method for midfoot deformity correction, based on reference lines and angles (RLA) of talus and first metatarsal of 64 normal radiographs from 55 patients. The anatomic lateral talometatarsal angle (aLTMA), resulting from the intersection of talus joint line (TJL), from the border of the articular surface of the talus to the posterior process of talus, and the anatomic axis of the first metatarsal, was 28.5° ± 4.5°. The intersection of those 2 lines divided the TJL in 2 segments (ac and ab) with the ratio k1 = 0.7 ± 0.3. The length of the first metatarsal line was measured from its intersection with the TJL and first metatarsal head, and it was 3.6 times longer that of the TJL (k2). To analyze foot deformity, we propose to draw the TJL line as follows. Use the k1 ratio to determine the point where the aLMTA intersects the TJL. From this point, an idealized anatomic first metatarsal line should be drawn, at 28.5° from the TJL. The distal end of that line is based on the k2 ratio (3.6 × TJL length). Next, the actual anatomic lateral talometatarsal line of the deformed foot is drawn. The intersection between these 2 lines identifies the apex and magnitude of the deformity. Deformity correction planning using the proposed method was demonstrated and confirmed in 2 cases. A reference method for analysis and planning of midfoot sagittal plane deformity correction independent of foot position relative to the ankle joint or the presence of concomitant hindfoot deformity appears promising for future investigation and use.     

New Sagittal Plane Reference Parameters for Foot Deformity Correction Planning: The Vitruvian Foot

Currently available methods for analysis and planning of post-traumatic or congenital deformity correction of the foot have some limitations. The aim of this retrospective study was to establish reference lines and angles (RLAs), and the resulting ratios, based on reproducible anatomic points on sagittal feet radiographs. The key starting point of our evaluation was the previously undescribed length and position of the talus joint line (TJL), from the border of the articular surface of the talus and the posterior process of talus. First, we calculated the relationships between the TJL and the axes of the foot, particularly the anatomic and mechanical lateral talometatarsal angle axes of the first metatarsal. Then, we assessed the relationships with the calcaneus, particularly the lateral heel angle. Finally, we calculated the parameters (angles and coefficients k) derived from the TJL and the foot-bearing points (foot quadrilateral). A total of 64 normal radiographs from 55 patients were analyzed. The values that resulted are as follows: anatomic lateral talometatarsal angle = 28.5° ± 4.5°, mechanical lateral talometatarsal angle = 23.6° ± 3.2°, lateral heel angle = 15.2° ± 3.4°, foot quadrilateral: abc = 144.6° ± 9.4°, bcd = 31.3° ± 2.6°, cda = 79.2° ± 9.8°, dab = 105.0° ± 8.3°, k1 = 3.09 ± 0.4, k2 = 3.77 ± 0.78, and k3 = 1.56 ± 0.24. Sagittal plane reference lines and angles are proposed, providing quantitative values for reference. These parameters have the potential to be easily implemented in foot deformity analysis and correction planning.     

Digital Planning for Foot and Ankle Deformity Correction: Evans Osteotomy

Preoperative planning is commonly performed for many foot and ankle procedures. The purpose of the present study was to prospectively determine the preoperative digital planning accuracy of predicting the calcaneal graft size used during the “Evans” calcaneal osteotomy. Preoperative digital deformity correction planning, using a standard planning method (TraumaCad^® software), was performed on 10 feet scheduled to undergo an Evans procedure. Of the 10 patients, 6 were female and 4 were male, with an average age of 43 ± 22 years. Digital planning was used to predict the Evans graft size. The surgeon was unaware of the predicted graft size, which was then compared with the actual graft size inserted during the procedure. In addition, the pre- and postoperative radiographic angles were recorded and compared (anteroposterior view, talo–first metatarsal angle, calcaneocuboid abduction; lateral view, calcaneal inclination angle; and axial view, tibial–calcaneal angle). The average preoperative talo–first metatarsal angle, calcaneocuboid angle, calcaneal inclination angle, and tibial–calcaneal angle measured 21° ± 9.6°, 28.3° ± 9.0°, 13.8° ± 5.7°, and 15.3° ± 8.2°, respectively. The preoperative tibial–calcaneal position was 2.8 ± 1.2 mm. The radiographic weightbearing angles measured at an average follow-up of 7.4 (range 6 to 12) months improved to 6.3° ± 7.4° (p = .0015), 12.3° ± 6.1° (p < .001), 21.3° ± 7.7° (p = .0122), and 2.2° ± 3.6° (p = .0019) for the talo–first metatarsal, calcaneocuboid abduction, calcaneal inclination, and tibial–calcaneal angles, respectively. The final tibial–calcaneal position measured 1.4 ± 0.7 mm (p < .001). The preoperative Evans graft measurement (11.8 ± 2.6 mm) compared with the actual graft (12.2 ± 1.3 mm) placed was within 0.4 ± 1.8 mm (p = .51). Preoperative digital planning for Evans calcaneal osteotomy has been shown to be a valuable tool for predicting the surgical graft size for accurate pedal realignment.     

Pronation of the First Metatarsal in Hallux Valgus Deformity

Axial rotation of the 1^st metatarsal (M1) as a factor in the development of hallux valgus (HV) deformity was described early by authors in the consideration of the pathology. However, for almost two decades, it was largely overlooked as HV was thought to be a two dimensional forefoot deformity bound in the transverse and sagittal planes. Thus, during this time period, many of the methods developed to measure and describe this deformity were biplanar in nature, adding to the limited understanding of this deformity. Subsequently, operative techniques for HV were also devised to correct any deformity of these two planes, leaving the frontal rotational status of the M1 uncorrected. Recently, as our imaging and understanding of this deformity improves, authors and clinicians have begun to re-consider M1 axial rotation as a principal feature of HV. The aim of this paper is to provide the most recent understanding of M1 axial rotation and how its consideration has changed temporally within the field of foot and ankle surgery.     

Observed Changes in Radiographic Measurements of the First Ray after Frontal Plane Rotation of the First Metatarsal in a Cadaveric Foot Model

We observed the changes in the angular measurements commonly used in the evaluation of the first metatarsal and first metatarsophalangeal joint in cadaveric specimens before and after frontal plane rotation of the first metatarsal. Measurements of the first and second intermetatarsal angle (IMA), hallux abductus angle, proximal articular set angle, and tibial sesamoid position (TSP) were taken after varying degrees of varus and valgus rotation of the first metatarsal. Standard dorsoplantar radiographs were taken at 0°, 10°, 20°, and 30° of valgus rotation of the first metatarsal and repeated at 10°, 20°, and 30° varus rotation of the first metatarsal. The data were analyzed using a mixed linear model to compare the change in each angle measurement over the range of valgus and varus rotation. The change in the TSP was significant in both valgus and varus rotations (p = .0004 and p = .028, respectively), an increase in valgus rotation causing an increase in the TSP and an increase in varus rotation causing a decrease in TSP. The change in the IMA was significant compared with valgus rotation (p = .028), showing that as the valgus rotation increased, the IMA also increased. However, compared with the varus rotation, the correlation was not significant (p = .18). The proximal articular set angle and hallux abductus angle measurements, compared with metatarsal rotation, showed positive trends but were not statistically significant. From our results and a review of the published data, we have hypothesized that frontal plane rotation of the first metatarsal is an integral component of hallux abducto valgus pathologic features, specifically in relation to the TSP and IMA.     

Bony Landmarks for Determining the Mechanical Axis of the Femur in the Sagittal Plane during Total Knee Arthroplasty

Background

There is no accepted landmark for the mechanical axis of the femoral axis in sagittal plane in conventional total knee arthroplasty.

Methods

As palpable anatomic landmarks of the femur, lateral epicondyle, and anterior margin of the greater trochanter were identified. The line connecting these two landmarks was defined as the "palpable sagittal axis". The mechanical axis of the femur was compared with the palpable sagittal axis and the distal femoral anterior cortex axis. These axes were also compared with sagittal bowing of the femur.

Results

The distal femoral anterior cortex axis and the palpable sagittal axis were flexed by 4.1° and 2.4° more than the sagittal mechanical axes, respectively (p < 0.05). However, the palpable sagittal axis was not correlated with sagittal bowing of the femur (Spearman''s rs, 0.17; p = 0.14).

Conclusions

The palpable sagittal axis showed a consistent relationship with the sagittal mechanical femoral axes regardless of the severity of the sagittal bowing of the femur.     

Three-Dimensional Printing and Surgical Simulation for Preoperative Planning of Deformity Correction in Foot and Ankle Surgery

A paucity of published data is available describing the methods for the integration of 3-dimensional (3D) printing technology and surgical simulation into orthopedic surgery. The cost of this technology has decreased and the ease of use has increased, making routine use of 3D printed models and surgical simulation for difficult orthopedic problems a realistic option. We report the use of 3D printed models and surgical simulation for preoperative planning and patient education in the case of deformity correction in foot and ankle surgery using open source, free software.     

Minimally Invasive Retrocapital Osteotomy of the First Metatarsal in Hallux Valgus Deformity

OBJECTIVE: Percutaneous retrocapital distal osteotomy of the first metatarsal for surgical treatment of hallux valgus. INDICATIONS: Mild to moderate hallux valgus deformity in both juveniles and adults. Recurrent hallux valgus deformity after previous surgery. CONTRAINDICATIONS: Severe degenerative changes of the first metatarsophalangeal joint (hallux valgus et rigidus). Previous Keller's procedure. SURGICAL TECHNIQUE: A percutaneous distal linear osteotomy of the first metatarsal is performed and stabilized with a Kirschner wire. The surgical technique follows these steps: distal Kirschner wire insertion; skin incision; sparse periosteal detachment; distal retrocapital osteotomy of the first metatarsal; correction of the first intermetatarsal angle by lateral displacement of the capital fragment; stabilization with Kischner wire insertion into the proximal metatarsal; postoperative taping. RESULTS: The patients were satisfied following 107 (91%) of 118 consecutive percutaneous procedures with a follow-up of 35.9 months (range 24-78 months). According to the American Orthopaedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal-interphalangeal scale for the clinical assessment, a mean score of 88.2 +/- 12.9 was obtained at follow-up. The clinical results can be compared to those obtained with open techniques, with the advantages of a minimally invasive procedure.     

Metatarsal Head Resection in the Rheumatoid Foot: 5-Year Follow-Up With and Without Resection of the First Metatarsal Head

Twenty-nine patients (45 feet) who underwent metatarsal head resections for rheumatoid forefoot deformities were reviewed retrospectively at a mean follow-up of 6.57 years (range, 5-9.3 years). Resections were confined to the lesser metatarsal heads in 16 feet because of a lack of involvement in the first metatarsal head. In the remaining 29 feet, all metatarsal heads were resected. A questionnaire was provided to assess subjective outcomes. Thirty-three feet (73.3%) had no pain or only mild pain, 5 feet (11%) had moderate pain, and 7 (15.5%) had severe pain. Among the 29 feet with panmetatarsal head resections, 5 (17%) required revision of metatarsal stumps at an average follow-up of 55.2 months (range, 17-84 months; standard deviation, 26.88). Among the 16 feet with only lesser metatarsal head resections, 7 (43.75%) required subsequent first metatarsal head resections at an average follow-up period of 33.14 months (range, 13-56 months; standard deviation, 16.54). In conclusion, metatarsal head resection is a simple procedure that gives long-term pain relief in over two thirds of the patients who have rheumatoid forefoot deformities. A high rate of recurrence of pain and subsequent resection of first metatarsal head is noted if it is not resected primarily. We recommend a low threshold for the inclusion of some form of primary reconstruction of the first metatarsophalangeal joint when resection arthroplasty is performed on the lesser toes.     

Tarsal Tunnel Decompression in Leg Lengthening and Deformity Correction of the Foot and Ankle

Decompression of the tarsal tunnel has been performed since the 1960s and has resulted in variable outcomes. The success rate of this procedure has ranged from 44% to 95%. We review the anatomy of the tarsal tunnel region and offer a detailed surgical approach for the decompression of its contents. We also discuss the role of this procedure in leg lengthening and deformity correction of the foot and ankle.     

Correction of Postaxial Metatarsal Polydactyly of the Foot by Percutaneous Ray Amputation and Osteotomy

Polydactyly of the foot is a congenital anomaly characterized by the appearance of all or part of 1 or more additional rays. The patient with this condition might complain of an abnormal cosmetic appearance or difficulty with footwear. A minimally invasive technique for correction of postaxial metatarsal polydactyly of the foot is presented in this techniques report.     

Fusion of the First Metatarsophalangeal Joint and Second to Fifth Metatarsal Head Resection for Rheumatoid Forefoot Deformity

The goals of the present study were to evaluate the mid-term results of first metatarsophalangeal joint fusion combined with second to fifth metatarsal head resection in rheumatoid forefoot deformity and identify the prognostic factors. The inclusion criteria were 2010 American College of Rheumatology and/or European League Against Rheumatism criteria for rheumatoid arthritis; symptomatic forefoot deformity; first metatarsophalangeal joint fusion and second to fifth metatarsal head resection; and a minimum of 4 years of follow-up data available. The patients were evaluated using the Disease Activity Score 28 for rheumatoid arthritis, Health Assessment Questionnaire for Rheumatoid Arthritis, Foot Function Index, forefoot American Orthopaedic Foot and Ankle Society scale, and weightbearing radiographs. Different pre-, intra-, and postoperative variables were investigated to identify the prognostic factors. Sixty-two patients (89 feet) with a mean age of 60.8°± 9.4 years and 85.5°± 22.4 months of follow-up data were included. The preoperative American Orthopaedic Foot and Ankle Society scale score was 33.4 ± 16 points and improved significantly (p < .001) after surgery (mean 82.9 ± 11.7 points). The mean Foot Function Index improved significantly (p < .001) from 131.6 ± 37.4 to 77.4 ± 46.3 points at the last follow-up visit. Only the revision surgery variable was significantly (p = .02) related to poor outcomes. Revision was necessary in 8 feet (9%). This procedure produced satisfactory results. Poor outcomes were significantly related to the necessity for revision surgery for nonunion, malunion, inadequate metatarsal resection, and painful hardware.     

Effect of Acute Alterations in Foot Strike Patterns during Running on Sagittal Plane Lower Limb Kinematics and Kinetics

The purpose of this study was to determine the effect of foot strike patterns and converted foot strike patterns on lower limb kinematics and kinetics at the hip, knee, and ankle during a shod condition. Subjects were videotaped with a high speed camera while running a 5km at self-selected pace on a treadmill to determine natural foot strike pattern on day one. Preferred forefoot group (PFFG, n = 10) and preferred rear foot group (PRFG, n = 11) subjects were identified through slow motion video playback (n = 21, age = 22.8±2.2 years, mass = 73.1±14.5 kg, height 1.75 ± 0.10 m). On day two, subjects performed five overground run trials in both their natural and unnatural strike patterns while motion and force data were collected. Data were collected over two days so that foot strike videos could be analyzed for group placement purposes. Several 2 (Foot Strike Pattern –forefoot strike [FFS], rearfoot strike [RFS]) x 2 (Group – PFFG, PRFG) mixed model ANOVAs (p < 0.05) were run on speed, active peak vertical ground reaction force (VGRF), peak early stance and mid stance sagittal ankle moments, sagittal plane hip and knee moments, ankle dorsiflexion ROM, and sagittal plane hip and knee ROM. There were no significant interactions or between group differences for any of the measured variables. Within subject effects demonstrated that the RFS condition had significantly lower (VGRF) (RFS = 2.58 ± .21 BW, FFS = 2.71 ± 0.23 BW), dorsiflexion moment (RFS = -2.6 1± 0.61 Nm·kg^-1, FFS = -3.09 ± 0.32 Nm·kg^-1), and dorsiflexion range of motion (RFS = 17.63 ± 3.76°, FFS = 22.10 ± 5.08°). There was also a significantly higher peak plantarflexion moment (RFS = 0.23 ± 0.11 Nm·kg^-1, FFS = 0.01 ± 0.01 Nm·kg^-1), peak knee moment (RFS = 2.61 ± 0.54 Nm·kg^-1, FFS = 2.39 ± 0.61 Nm·kg^-1), knee ROM (RFS = 31.72 ± 2.79°, FFS = 29.58 ± 2.97°), and hip ROM (RFS = 42.72 ± 4.03°, FFS = 41.38 ± 3.32°) as compared with the FFS condition. This research suggests that acute changes in foot strike patterns during shod running can create alterations in certain lower limb kinematic and kinetic measures that are not dependent on the preferred foot strike pattern of the individual. This research also challenges the contention that the impact transient spike in the vertical ground reaction force curve is only present during a rear foot strike type of running gait.

Key points

• Footstrike pattern changes should be individually considered and implemented based on individual histories/abilities
• Forefoot strike patterns increase external dorsiflexion moments
• Rearfoot strike patterns increase external knee flexion moments
• Recreational shod runners are able to mimic habitual mechanics of different foot strike patterns

Key words: Forefoot, rearfoot, joint moments, range of motion     

Comparison between Pin Fixation and Combined Screw Fixation in Proximal Chevron Metatarsal Osteotomy for Hallux Valgus Deformity Correction

BackgroundProblems associated with hallux valgus deformity correction using Kirschner-wire (K-wire) fixation include pin pullout and loss of stability. These complications are pronounced in the osteopenic bone, and few reports have focused on pin versus screw fixation. We examined the use of additional screw fixation to avoid these problems. The aim of this study was to compare outcomes of K-wire fixation (KW) and a combined K-wire and screw fixation (KWS).MethodsTwo groups with hallux valgus deformity, who were treated with a proximal chevron metatarsal osteotomy (PCMO), were compared based on the fixation method used. The KW group included 117 feet of 98 patients, and the KWS group included 56 feet of 40 patients. Clinically, the preoperative and final follow-up visual analog scale (VAS) pain score, American Orthopedic Foot & Ankle Society (AOFAS) hallux score, and patient satisfaction score were evaluated. Radiographically, hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured.ResultsThe mean VAS score decreased from 6.3 preoperatively to 1.6 postoperatively in the KW group and from 5.7 preoperatively to 0.5 postoperatively in the KWS group (p < 0.001). The mean AOFAS scores of the KW and KWS groups improved from 59.4 and 58.2, respectively, to 88.9 and 95.3, respectively (p < 0.001). Eighty-five percent in the KW group and 93% in the KWS group were satisfied with surgery. Clinical differences were not significant. The mean HVAs decreased from 34.7° to 9.1° in the KW group and from 38.5° to 9.2° in the KWS group (p < 0.001). The mean IMA decreased from 14.5° (range, 11.8°–17.2°) to 6.4° (range, 2.7°–10.1°) in the KW group and from 18.0° (range, 14.8°–21.2°) to 5.3° (range, 2.5°–8.1°) in the KWS group (p < 0.001). When IMA values at the 3-month postoperative and the final follow-up were compared, the IMA was significantly increased only in the KW group (p < 0.001) and no difference was found in the KWS group (p = 0.280).ConclusionsWe found a statistically significant difference in the decrease in IMA between the 2 groups. We recommend the combined pin and screw fixation in PCMO to enhance fixation stability and prevent potential hallux valgus correction loss.     

Soft Tissue Management and Tibialis Posterior Tendon Transfer in Acute Correction for Neglected Drop Foot Deformity

Acute correction of rigid drop foot deformity can be problematic due to the skin defect that may occur in the medial part of the ankle. The purpose of this study is to present an innovative solution for this problem. We hypothesized that acute correction for rigid ankle contractures without arthrosis might be possible if the medial skin defect could be closed. Therefore, we described a surgical technique for acute functional correction of rigid drop foot deformities. The closure of the medial defect was performed by applying a flap and partial-thickness skin graft. We have retrospectively evaluated the results of 18 patients who were treated between 2010 and 2016 with this technique. The mean age of the patients was 37 ± 9.5 (22-56) years. Foot drop etiology was firearm-related nerve injury. Corrections were performed after 14.6 ± 7.9 (8-38) months following the injury. At the end of an average follow-up period of 44.4 ± 6.2 (37-60) months, 14 of 18 patients (78%) recovered without complications, 3 patients experienced partial loss in the medial skin graft region, and 1 patient developed a superficial infection. None of the patients have developed pes planus. We observed that the ankle flexion contracture, which was 34° ± 9.2° (20°-50°) preoperatively, could reach an average of 2.2° ± 2.5° (0°-6°) dorsiflexion after surgery. We suggest that acute correction and tibialis posterior tendon transfer in the treatment of rigid foot drop deformity can be performed with an effective skin closure with low soft tissue complications.