Transarticular Lateral Release Versus Percutaneous Lateral Release for Hallux Valgus

background Hallux valgus (HV) is a common forefoot disorder in need of surgical intervention after failed conservative treatment. Surgical treatment of HV generally includes different kinds of osteotomy in combination with different distal soft tissue procedures (DSTP). Commonly used DSTP are open first-web lateral release, transarticular lateral release (TALR), and percutaneous lateral release (PCLR). In some studies, TALR showed similar surgical outcomes with open first-web space lateral release. Besides, PCLR has been described with satisfactory outcomes. TALR and PCLR are gaining popularity due to their less invasive approach and potential in combination with a distal metatarsal Chevron osteotomy (DMCO). Currently, there is no study comparing the surgical results between TALR and PCLR for surgical reconstruction of HV.

Aim The aim of this prospective randomized trial is to compare the surgical outcomes of TALR versus PCLR, both in combination of DMCO, for the treatment of HV. Our hypothesis is that TALR would achieve a better surgical outcomes than PCLR.

This study will be conducted from January, 2021 to December, 2024. A total of 140 participants are included with 70 participants in each group. Participants are allocated to TALR or PCLR group before index surgery according to a computer-generated randomization list.

For all patients, after regional nerve block and adequate sedation, intraoperative stress test is performed for flexibility of first metatarsophalangeal joint (MTPJ).6 The test is confirmed with dorsoplantar fluoroscopy. Only the cases with negative results (passive correction is not possible) are included. Then, a medial incision of 2.5-cm is made at distal metatarsal head and a reverse L-shaped medial capsulotomy is made followed by TALR or PCLR.

After TALR or PCLR, medial bunionectomy is performed. DMCO is made with the apex at distal metatarsal neck and angle of 60 to 90 degrees. The metatarsal head is laterally moved and fixed with one or 2 oblique headless compression screws.

Postoperative followup The patients are followed up at two weeks for removal of stitches, then 1-month, 2-month, 3-month, 6-months, 1-year, and annually after 1 year for radiographic , functional assessments, and evaluation of complications.

Power analysis for patient number With the assumption of mean HVA are 10 degrees for TALR group and 15 degrees for PCLR group at final followup, and a standard deviation of 8 degrees for both groups, the calculated effect size d is 0.625. In order to achieve the α error probability of 0.05 and power of 0.95, 68 participants in each group are necessary with a total of 136 participants in this study.

Statistical analysis In the comparisons between TALR and PCLR groups, the independent two samples t-test and the Mann-Whitney test are performed for normal and non-normal distributed data respectively, and the Fisher's exact test is performed for categorical data. P-values less than 0.05 is considered to be statistical significant. The statistical analyses are performed by using SPSS 25.0 statistics software (SPSS Inc, Chicago, USA).

Clinical relevance

1. Compare the differences of surgical outcomes between TALR and PCLR. These results could offer valuable information for foot and ankle surgeon.
2. If PCLR is not adequate to achieve satisfactory outcomes, the minimally invasive surgery using PCLR for HV is not recommended.

Eligibility Criteria:
Inclusion Criteria:

* Age equal or greater than 20 years
* Hallux valgus angle (HVA) equal or greater than 20 degrees
* Persistent symptoms after failed conservative treatment
* Receiving DMCO for HV

Exclusion Criteria:

* Underlying rheumatoid or other inflammatory arthritis
* Hallux rigidus
* Recurrent hallux valgus after previous surgery
* First tarsometatarsal hypermobility
* A positive intraoperative stress test for lateral soft tissue release