Open wedge metatarsal osteotomy versus crescentic osteotomy to correct severe hallux valgus deformity – A prospective comparative study
Introduction
Hallux valgus surgery is a very common forefoot operation, and several techniques have been introduced to correct the deformity [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11]. Hallux valgus often leads to pain, deformity of the big toe and secondary complications such as abnormal gait and ulcers on the foot. Numerous techniques have been introduced and published regarding correcting hallux valgus. The operation techniques can be divided into distal metatarsal osteotomy (DMO), mid-shaft osteotomies or proximal metatarsal osteotomy (PMO) [1], [12], [13], [14], [15], [16]. The Akin procedure is used to correct the pronation deviation of the proximal phalanx and to correct hallux valgus interphalangealis, when this is still persisting after correcting the hallux valgus (HVA) and inter-metatarsal (IMA) angle [17]. Only very few prospective randomized investigations comparing different operation methods for hallux valgus have been published [8], [12], [13]. In our department the distal chevron procedure is used for patients with a HVA less than 35 degrees and an IMA less than 15 degrees [8]. For patients with HVA larger than 35 degrees or IMA larger than 15 degrees, we use the PMO to correct the hallux valgus deformity [1], the PMO is in general considered technically more demanding and is more likely to give complications. The DMO is considered mainly to be advisable in operations correcting hallux valgus with a limited HVA and IMA. The aim of the operation for hallux valgus is to diminish pain and to correct the IMA and HVA with a very low incidence of complications.
The hypothesis of this study was that the open wedge osteotomy procedure was equivalent or superior to the crescentic osteotomy, measured by the parameters: postoperative HVA, IMA, AOFAS score, VAS score and relative length of 1 compared to 2 metatarsal, measured preoperative, 4 and 12 months postoperatively.
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Materials and methods
During the period 1st January 2009 to 1st January 2011, 45 consecutive patients were included in the prospective study, which was approved by the Danish Ethical Committee. The inclusion criteria were aged 15–70 years, hallux valgus angle >35 degrees and inter-metatarsal angle >15 degrees, the measurement was evaluated on anterior–posterior (AP) weight bearing radiographs. Patients with rheumatoid arthritis, osteoarthritis of the MTP joint, spasticity of any kind, vascular diseases or pregnancy
Surgical technique
Both the open wedge osteotomy and the crescentic osteotomy consist of a distal lateral release and bunionectomy prior to the proximal osteotomy. Firstly, a dorsal incision was made in the inter-metatarsal space between 1st and 2nd ray. Release of the adductor hallucis tendon, the deep transverse inter-metatarsal ligament and lateral capsule were executed.
The second incision was made midline medial over the medial eminence to remove the medial eminence and perform a capsulorrhaphy. The third
Statistics
Analysis of the data distribution was done making probit plots. Data were found to be normally distributed, and for this reason, parametric tests were used. An independent t-test was used to compare the results after the proximal crescentic osteotomy and the open wedge osteotomy. Significance was reached with a p-value less than 0.05 (p < 0.05).
Results
Mean hallux valgus angle in group 1 (crescentic osteotomy) decreased from 39.0̊ preoperatively to 24.1̊ after 4 months and 27.9̊ after 12 months. Mean hallux valgus angle in group 2 (open wedge osteotomy) decreased from 38.3̊ preoperatively to 21.4̊ after 4 months and 27.0̊ after 12 months (Table 1).
Mean inter-metatarsal angle in group 1 was 19.0̊ preoperatively, 11.6̊ after 4 months and 12.6̊ after 12 months. Mean inter-metatarsal angle in group 2 was 18.9̊ preoperatively, 12.0̊ after 4 months
Complications
Implant removal was performed in 5 of 23 patients in group 1, and in 4 out of 22 patients in group 2. The screw used in group 1 for the crescentic osteotomy was directed from proximal–medial–dorsal to a distal–lateral direction. The aim was to place the screw so far medially that irritation from the extensor tendon did not occur, but soft tissue irritation can still be a problem. Screw irritation was the reason for hardware removal in 2 of 5 patients in group 1. The other 3 patients in group 1
Discussion
Only very few prospective randomized trials have been made comparing different kinds of operations in hallux valgus surgery. No significant difference was found between groups 1 and 2 comparing preoperative angle values (39.1̊ and 38.3̊) 4 months postoperatively (24.1̊ and 21.4̊) and 12 months postoperatively (27.2̊ and 27.0̊) (Table 1). Similarly, no significant difference was found looking at the IM angle improvement of the two groups comparing preoperative values of groups 1 and 2 (19.0̊ and
Perspective
As the open wedge osteotomy is found to be equivalent to the crescentic osteotomy, this will be our standard in the future when correcting severe hallux valgus with a proximal osteotomy as the procedure is less technically challenging. For both groups a loss of correction was seen in the interval from 4 to 12 months. This could be due to instability of the TMT joint. If this is the case a Lapidus procedure might be more relevant than a proximal osteotomy in patients with a large IM and HV
Limitations
Our study has several limitations. The four senior surgeons were aiming for “desired” correction when performing the two different types of osteotomies, verifying the correction with fluoroscopy but with no specific aim of angle correction. The Akin procedure was done, when the surgeon felt there was a “need,” a risk of collision between 1st and 2nd toe.
If more precise objective goals, especially radiologically, had been standardized, maybe better correction would have been achieved, and maybe
Conclusion
Crescentic osteotomy and open wedge osteotomy improves AOFAS score and VAS scores on patients operated with severe hallux valgus. No significant difference was found in the two groups looking at the postoperative improvement of HVA and IMA measured 4 and 12 months postoperatively. The postoperative VAS score and AOFAS score were comparable for the two groups with no significant difference. An expected tendency to gain better length of the first metatarsal using the open wedge osteotomy compared
Conflict of interest
None of the authors have any conflicts of interest to declare.
Acknowledgement
We want to thank PhD Jens Lauridsen, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, for his inspiring and unsurpassed help with the statistical calculations.
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