Structures at Risk From an Intermetatarsal Screw for Lapidus Bunionectomy: A Cadaveric Study

Radiographic Evaluation of First Tarsometatarsal Joint Arthrodesis for Hallux Valgus Deformity: Does the Fusion of the First to the Second Metatarsal Base Reduce the Radiological Recurrence Rate?

BACKGROUND

Modified Lapidus arthrodesis (MLA) is a well-established treatment option for symptomatic hallux valgus deformity (HVD). However, recurrence of the deformity remains a concern. The goal of this study was to evaluate the effect of an additional intermetatarsal fusion on the radiographic recurrence rate after first tarsometatarsal (TMT-I) arthrodesis.

METHODS

This is a retrospective evaluation of 56 feet that underwent TMT-I arthrodesis for moderate to severe HVD. Twenty-three feet received an isolated arthrodesis of the TMT-I joint (TMT-I), whereas 33 feet received an additional fusion between the base of the first and the second metatarsal bone (TMT-I/II). Various radiological parameters were determined preoperatively, 6 weeks and at a mean of 2 years postoperatively.

RESULTS

The intermetatarsal angle (IMA) and the hallux valgus angle (HVA) were significantly lowered at both follow-up evaluations in both groups. In the TMT-I/II group, the initial reduction of HVA was significantly higher (29.3° vs 21.1°). This difference disappeared by the second follow-up, leaving no significant differences between both techniques at final follow-up. Radiological recurrence rates of HVD were comparable in both groups.

CONCLUSIONS

Isolated TMT-I arthrodesis provides reliable radiological results in the correction of HVD. Whether additional fusion of the first and second metatarsal base should be routinely performed remains unclear.

LEVELS OF EVIDENCE

Level 3.

Maintenance of Correction of the Modified Lapidus Procedure With a First Metatarsal to Second Metatarsal Screw With "Spot Weld" Technique: A Retrospective and Radiographic Analysis

Lapidus first tarsometatarsal (TMT) arthrodesis gained popularity for its ability to correct large deformities especially in cases of medial column instability. Despite solid first TMT fusion, instability between the first and second columns can result in loss of intermetatarsal (IM) angle correction over time. A "spot weld" or fusion between the first and second metatarsal may improve maintenance of correction. This retrospective study reviewed cases of Lapidus arthrodesis with first to second metatarsal base screw fixation for maintenance of IM correction and determine whether a "spot weld" is predictive of maintenance. A total of 90 cases (77 patients) performed by a single surgeon met inclusion with average follow-up of 309 days. First TMT fusion occurred in 87/90 (96.7%) cases with 76 dorsal plate, 10 dorsal staple, and 4 all screws. No incidence of complications related to the 1-2 screw was noted. Mean preoperative IM 1-2 angle 14.90°, mean correction to 6.22° post-operative and final maintained correction at 7.10°, mean loss of correction 0.87°. There were "spot welds" in 65/90 (72.2%) with mean loss of 0.48° versus loss of 1.88° in "no spot weld" subgroup (p < .001). Cases with no spot weld and screw lucency lost 2.25° (p < .001). Loss of IM 1-2 correction can occur due to first and second ray intra-column instability even in cases of solid first TMT arthrodesis. Incorporating a completed "spot weld" with bone grafting and first to second metatarsal screw was found to maintain correction with minimal loss (0.87°).

Intraoperative Technical Tips to Improve Fusion Between the First and Second Metatarsals in the Original Lapidus Procedure

The modified Lapidus procedure (MLP), which consists of fusion between the first metatarsal (M1) and medial cuneiform, has been widely performed with satisfactory clinical outcomes, but it has a variable nonunion rate ranging between 4% and 10% and loss of correction in up to 5.8% of the cases. Excessive motion around the site of tarsometatarsal arthrodesis, specially at the intercuneiform joint, is probably the reason. The original Lapidus procedure (OLP), which includes fusion of the M1 to second metatarsal (M2), may be beneficial in preventing nonunion and recurrence. The objective of this study was to describe intraoperative technical tips in the OLP to improve M1 to M2 fusion, which may prevent complications. Since the Lapidus procedure continues to gain popularity, it is the authors opinion that the OLP requires special attention because it is a more technically demanding surgery compared to the MLP.Level of Evidence: Level V: Expert opinion.

Location of the Deep Plantar Artery: A Cadaveric Study

BACKGROUND

The deep plantar (D-PL) artery originates from the dorsalis pedis artery in the proximal first intermetatarsal space, an area where many procedures are performed to address deformity, traumatic injury, and infection. The potential risk of injury to the D-PL artery is concerning. The D-PL artery provides vascular contribution to the base of the first metatarsal and forms the D-PL arterial arch with the lateral plantar artery.

METHODS

In an effort to improve our understanding of the positional relationship of the D-PL artery to the first metatarsal, dissections were performed on 43 embalmed cadaver feet to measure the location of the D-PL artery with respect to the base of the first metatarsal. Digital images of the dissected specimens were acquired and saved for measurement using in-house software. Means, standard deviations, and 95% confidence intervals (CIs) were calculated for all of the measurement parameters.

RESULTS

We found that the origin of the D-PL artery was located at a mean ± SD of 11.5 ± 3.9 mm (95% CI, 4.5-24.7 mm) distal to the first metatarsal base and 18.6% ± 6.5% (95% CI, 8.1%-43.4%) of length in reference to the proximal base. The average interrater reliability across all of the measurements was 0.945.

CONCLUSIONS

This study helps clarify the anatomical location of the D-PL artery by providing parameters to aid the surgeon when performing procedures in the proximal first intermetatarsal space. Care must be taken when performing procedures in the region to avoid unintended vascular injury to the D-PL artery.

Lapidus, a Percutaneous Approach

Described in the early 1900s by Albrecht and Lapidus, the Lapidus procedure became an important tool in the armamentarium. With the increase of percutaneous techniques, the development of a percutaneous Lapidus seemed obvious.