Correction of hallux valgus deformity using the center of rotation of angulation method

Weightbearing Imaging Assessment of Midfoot Instability in Patients with Confirmed Hallux Valgus Deformity: A Systematic Review of the Literature

Hallux valgus deformity (HVD) involves subluxation of the first metatarsophalangeal joint. While HVD is primarily considered a forefoot condition, midfoot instability may play a significant role in its development and severity. However, very few studies have placed a heavy emphasis on studying this phenomenon. Therefore, this review had a particular focus on understanding midfoot instability based on weightbearing imaging assessments of the TMT joint. This review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and searched five databases for studies on midfoot instability in HVD patients. The severity of HVD was defined by hallux valgus angle (HVA) and distal metatarsal articular angle (DMAA). Data was extracted, and articles were graded using the Methodological Index for Non-Randomized Studies (MINORS). Of 547 initially retrieved articles, 23 met the inclusion criteria. Patients with HVD showed higher HVA and DMAA on weightbearing radiographs (WBRG) and weightbearing computed tomography (WBCT) compared to healthy individuals. Midfoot instability was assessed through intermetatarsal angle (IMA) and tarsometatarsal angle (TMT angle). Patients with HVD exhibited greater IMA and TMT angles on both WBRG and WBCT. This review highlights the importance of weightbearing imaging assessments for midfoot instability in HVD. IMA and TMT angles can differentiate between healthy individuals and HVD patients, emphasizing the significance of midfoot assessment in understanding HVD pathology. These findings validate the limited evidence thus far in the literature pertaining to consistent midfoot instability in HVD patients and are able to provide ample reasoning for physicians to place a larger emphasis on midfoot imaging when assessing HVD in its entirety.

Cavovarus Deformity: Why Weight-Bearing Computed Tomography Should Be a First-Line Imaging Modality

Cavovarus foot is a complex three-dimensional deformity, which includes a wide range of clinical conditions from subtle deformities to disabling feet. In this article, the authors discuss the role of weight-bearing computed tomography, which might enable to avoid double imaging (radiographs + tomography) in patients for which a detailed osteoarticular assessment is required, with the advantage to obtain tomographic images in standing position and a reduction of radiation exposure.

The First Metatarsophalangeal Joint: Updates on Revision Arthrodesis and Malunions

First metatarsophalangeal joint (MPJ) arthrodesis procedures are a mainstay of forefoot surgery and are associated with high rates of patient satisfaction for addressing a multitude of first ray pathologic conditions. This procedure is often also used as a fallback option for the revision of poor outcomes after other surgical procedures involving the first ray. Despite its successes, there remain instances of complications that can develop after primary first MPJ arthrodesis. This article reviews first MPJ arthrodesis as a procedure for revisional surgery of the first ray, and potential surgical options after failed primary first MPJ arthrodesis.

A New Approach for the Correction of Type I Thumb Deformity Owing to Rheumatoid Arthritis

A major transition in the surgical treatment of rheumatoid arthritis has been facilitated by a recent paradigm shift in its diagnosis and treatment. Improved outcomes in the treatment of the rheumatoid thumb are desirable; however, the results of conventional surgery are less than ideal. Even if the rheumatoid arthritis is well-controlled, the progression of thumb deformity may persist owing to an ineffective deformity correction and an insufficient understanding of the mechanism by which the deformity occurs. The mechanism of rheumatoid thumb deformity should be considered, using it to base the appropriate correction. We applied a new deformity correction procedure that accounts for the mechanism of type I rheumatoid thumb deformity and obtained positive results without recurrence. Although the primary cause of type I thumb deformity is believed to be an extensor mechanism failure resulting from synovitis of the metacarpophalangeal (MCP) joint, surgical outcomes are negatively affected as a result of flexion contracture caused by the adductor pollicis (ADP). Because the ADP attaches to the ulnar sesamoid on the palmar side of MCP joint, we release the ADP tendon to improve flexion contracture of the MCP joint. We consider release of ADP to be effective in preventing the recurrence of flexion contracture of the MCP joint and re-tensioning of the extensor pollicis brevis. Rheumatoid thumb deformity can be restored by applying this procedure, improving a patient’s outcome.

Multicenter Early Radiographic Outcomes of Triplanar Tarsometatarsal Arthrodesis With Early Weightbearing

BACKGROUND

Hallux valgus is a multiplanar deformity of the first ray. Traditional correction methods prioritize the transverse plane, a potential factor resulting in high recurrence rates. Triplanar first tarsometatarsal (TMT) arthrodesis uses a multiplanar approach to correct hallux valgus in all 3 anatomical planes at the apex of the deformity. The purpose of this study was to investigate early radiographic outcomes and complications of triplanar first TMT arthrodesis with early weightbearing.

METHODS

Radiographs and charts were retrospectively reviewed for 57 patients (62 feet) aged 39.7 ± 18.9 years undergoing triplanar first TMT arthrodesis at 4 institutions between 2015 and 2017. Patients were allowed early full weightbearing in a boot walker. Postoperative radiographs were compared with preoperative radiographs for hallux valgus angle (HVA), intermetatarsal angle (IMA), tibial sesamoid position (TSP), and lateral round sign. Any complications were recorded.

RESULTS

Radiographic results demonstrated significant improvements in IMA (13.6 ± 2.7 degrees to 6.6 ± 1.9 degrees), HVA (24.2 ± 9.3 degrees to 9.7 ± 5.1 degrees), and TSP (5.0 ± 1.3 to 1.9 ± 0.9) from preoperative to final follow-up (P < .001). Lateral round sign was present in 2 of 62 feet (3.2%) at final follow-up compared with 52 of 62 feet (83.9%) preoperatively. At final follow-up, recurrence was 3.2% (2/62 feet), and the symptomatic nonunion rate was 1.6% (1/62 feet). Two patients required hardware removal, and 2 patients required additional Akin osteotomy.

CONCLUSION

Early radiographic outcomes of triplanar first TMT arthrodesis with early weightbearing were promising with low recurrence rates and maintenance of correction.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Evaluation of the Mechanical Axis of the First Ray Before and After First Metatarsal-Phalangeal Joint Reconstructive Surgery

LaPorta et al published a description of measurement of the mechanical axis of the first ray in an attempt to introduce center-of-rotation angulation principles into forefoot reconstructive surgery. They found significant differences in the measurement of the first intermetatarsal angle between groups of feet with and without hallux abducto valgus deformity, but they found no difference in the measurement of the M1-M2 mechanical axis angle between groups. The objectives of this study were to further investigate the proposed M1-M2 mechanical axis angle and to examine the effect of hallux abducto valgus corrective surgery on its measurement. We retrospectively evaluated weight-bearing dorsal-plantar projection radiographs taken in the angle and base of gait of 56 consecutive feet before and after first metatarsal-phalangeal joint corrective surgery. On each radiograph, we calculated the first intermetatarsal angle, the hallux abductus angle, the tibial sesamoid position, the M1-M2 mechanical axis angle, and the position of the sesamoids relative to the mechanical axis of the medial column. Statistically significant decreases were observed when comparing pre- versus post-operative measurement of the first intermetatarsal angle (-4.83°; p < .001), hallux abductus angle (-11.46°; p < .001), and tibial sesamoid position (-1.99 positional grade; p < .001). Statistically significant differences were also observed for the M1-M2 mechanical axis angle (-0.47°; p = .007) and the position of the sesamoids relative to the mechanical axis of the medial column (0.38 positional grade; p < .001), but it is unlikely that these results would be considered clinically significant given the differences of less than 1° and less than 1 positional grade, respectfully. The results of this investigation add to the body of knowledge and will hopefully lead to future investigations into the progression, evaluation, and treatment of the hallux abducto valgus deformity.

Using the Center of Rotation of Angulation Concept in Hallux Valgus Correction: Why Do We Choose the Proximal Oblique Sliding Closing Wedge Osteotomy?

Many different surgeries have been proposed for hallux valgus treatment, osteotomies being the currently recommended ones. Because of high recurrence rates, distal, diaphyseal and proximal osteotomies have been used to improve alignment and sesamoid reduction. The center of rotation of angulation (CORA) concept applies to any deformity and helps to completely realign 2 bone segments. When used with proximal osteotomies, bone displacement and angulation is performed obtaining complete deformity correction. The proximal oblique sliding closing wedge (POSCOW) osteotomy follows the CORA concept and permits preoperative planning. Future directions must include the correction of the pronation deformity of the metatarsal.

The Mechanical Axis of the First Ray: A Radiographic Assessment in Hallux Abducto Valgus Evaluation

The present report describes a new method of hallux abducto valgus deformity correction planning using the mechanical axis of the medial column (mechanical axis planning). This method of radiographic evaluation identifies an ideal position for the first metatarsal after correction and is useful regardless of the surgical procedure chosen. We retrospectively reviewed 200 radiographs to identify a "normal" value for the mechanical axis angle. We reviewed 100 radiographs of patients with hallux abducto valgus deformity (deformity group) and 100 radiographs of patients without hallux abducto valgus deformity (control group). The deformity group revealed an M1-M2 anatomic axis angle of 13.5° ± 2.83° and an M1-M2 mechanical axis angle of 11.58° ± 1°. The control group revealed an M1-M2 anatomic axis angle of 7.5° ± 1.76° and an M1-M2 mechanical axis angle of 11.19° ± 0.9°. The differences in the M1-M2 anatomic axis angle and M1-M2 mechanical axis angle were statistically significant between the control and deformity groups. We sought to provide a reliable method for planning hallux abducto valgus deformity correction by aligning the mechanical axis of the medial column and the mechanical axis of the first ray to the "normal" value of 11° to reduce the deformity.

A New Measure of Tibial Sesamoid Position in Hallux Valgus in Relation to the Coronal Rotation of the First Metatarsal in CT Scans

BACKGROUND

We aimed to find a new radiographic measurement for evaluating first metatarsal pronation and sesamoid position in hallux valgus (HV) deformity.

METHODS

Data from a clinical study of 19 control patients (19 feet) with no HV deformity were compared with preoperative data of 138 patients (166 feet) with HV deformities. Using a weightbearing plain radiograph in anteroposterior (AP) view, the intermetatarsal angles (IMAs) and the hallux valgus angles (HVAs) of the control and study groups were measured. Using a semi-weightbearing coronal computed tomography (CT) axial view, the α angle was measured in the control and study groups. In addition, the tibial sesamoid grades in plain radiograph tangential view and the CT axial view were measured. The tibial sesamoid position in an AP view was checked preoperatively. Based on these measurements, 4 types of HV deformities were defined.

RESULTS

The mean values of the α angle in the control and HV deformity groups (control group µ = 13.8 degrees, study group µ = 21.9 degrees) was significantly different. Among 166 HV feet, 145 feet (87.3%) had an α angle of more than 15.8 degrees, which is the upper value of the 95% confidence interval of the control group, indicating the existence of abnormal first metatarsal pronation in HV deformity. Four types of HV deformities were defined based on their α angles and tibial sesamoid grades in CT axial view (CT 4 position). Among 25.9% (43/166) of the study group, abnormal first metatarsal pronation with an absence of sesamoid deviation from its articular facet was observed. The prominent characteristic of this group was that they had high grades in the AP 7 position (≥5); however, in the CT 4 position, their grade was 0. This group was defined as the "pseudo-sesamoid subluxation" group.

CONCLUSIONS

Patients with HV deformities had a more pronated first metatarsal than the control group, with a greater α angle. Pseudo-subluxation of the sesamoids existed in 25.9% of our study group. From our results, we suggest that the use of the CT axial view in assessments of HV deformity may benefit surgeons when they make operative choices to correct these deformities. With regard to the pseudo-sesamoid subluxation group, the use of the distal soft tissue procedure is not surgically recommended.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Relationship of frontal plane rotation of first metatarsal to proximal articular set angle and hallux alignment in patients undergoing tarsometatarsal arthrodesis for hallux abducto valgus: a case series and critical review of the literature

Rotation of the first metatarsal, as a component of hallux abducto valgus, is rarely discussed and is not addressed as a component of most hallux valgus corrective procedures. We believe frontal plane rotation of the first metatarsal to be an integral component of hallux abducto valgus deformity (the "third plane of deformity") and believe de-rotation is necessary for complete deformity correction. We observed the change in angular measurements commonly used in the evaluation of hallux valgus deformity in patients who underwent a modified lapidus procedure. We measured the intermetatarsal angle, hallux abductus angle, proximal articular set angle, and tibial sesamoid position on weightbearing radiographs of 25 feet in 24 patients who had undergone tarsal metatarsal corrective arthrodesis and lateral capsular release. Specific attention was given to reduction of the frontal plane rotation of the first metatarsal during correction. Our results showed a change in the angular measurements observed by 4 investigators as follows. The mean change in the intermetatarsal angle was 10.1° (p < .0001). The mean change in the hallux abductus angle was 17.8° (p < .0001). The mean change in the proximal articular set angle was 18.7° (p < .0001). The mean change in the tibial sesamoid position was 3.8 (p < .0001). Also, a consistent valgus, or everted position of the first metatarsal, was noted as a component of the hallux abducto valgus deformity in our patient population and was corrected by varus rotation or inversion of the metatarsal. We also reviewed the current literature related to anatomic changes in the first ray in the patient with hallux valgus deformity and reviewed our hypothesis regarding the reduction in the proximal articular set angle, which we believe to be related to frontal plane rotation of the first metatarsal, resulting in a radiographic artifact.