Simultaneous Bilateral Isolated Hallux Valgus Correction Using the ReveL Distal Metatarsal Osteotomy: Clinical, Radiological and Pedobarographic Evaluation with a Minimum of 2 Year Follow Up

Hallux Valgus (HV) is an acquired forefoot deformity combining medial deviation of the first metatarsal and lateral deviation of the first phalanx of the great toe. Heredity is the major factor, but shoe wear and occupation should be taken into consideration. It is the most common forefoot deformity with patients reporting pain and trouble with shoe fitting and sports [1]. Its pathogenesis involves metatarsus varus primus, and weakening of the soft tissues on the medial side of the first metatarsophalangeal joint at the root of the deformity. The tendons of extensor and flexor hallucis longus are carried laterally with the phalanx, becoming adductors, and exacerbating the deformity [2,3]. Excessive pressure on the medial side of the joint causes local pain and inflammation, along with the deformity. Additional morbidity like transfer metatarsalgia can occur due to the load shift from a painful medial forefoot to more lateral regions [2].

Although aesthetic considerations intervene as well, hallux valgus has a significant detrimental impact on gait patterns contributing to instability and the risk of falling, particularly in older people [3].

Gonzalez et al. [4] observed a prevalence of 39% on a randomized population sample of at least 40 years old. In Switzerland HV prevalence is of 23%. It rises to 36% in the senior population (65 years and older) and affects more women (30%) than men (13%). Therefore, HV surgery is one of the most practiced forefoot procedures and numerous surgical techniques have been developed to treat this deformity.

The incidence of bilateral HV is high. Young et al. [5] describe a rate as high as 97.3% in their study. In a review of 52 patients that underwent chevron osteotomy for moderate to severe hallux valgus, Keun-Bae Lee et al. [6] shows no difference in the clinical and radiological outcomes between simultaneous bilateral and unilateral correction at 12 months minimum follow-up.

Helmy et al. [7] has shown excellent objective and subjective results with the ReveL osteotomy in unilateral surgeries.

The purpose of the present study was to examine the pertinence of simultaneous bilateral correction, using a distal metatarsal osteotomy called ReveL (Reversed L shape osteotomy) in the treatment of moderate to severe bilateral symptomatic hallux valgus deformity [7] and to determine the clinical and radiological outcomes after a minimum of two years follow-up. We also measured the postoperative plantar pressure distribution in comparison with a group of asymptomatic age- and gender-matched subjects.

Patients

Between May 2015 and April 2018, we performed 341 hallux valgus corrections at our institution. All procedures were performed by the senior author (PV) or under his supervision. 55 patients (110 feet) underwent a simultaneous bilateral isolated HV correction and met the inclusion criteria. There was no added surgical procedure in this group. 24 patients were lost to follow-up. Our ideal sample size was 47 feet according to the Charan [8] method, aiming for a 0.05 significance and a power of 80%. We thus studied a cohort of 31 patients (62 feet) with complete preoperative and postoperative clinical and radiological documentation including AOFAS [9] and EQ-5D [10] scores. They were followed for an average of 37 months (range 21 to 55 months). These 31 patients included 30 females and 1 male. The average was 49 years (range 21 to 77 years). Institutional review board approval was obtained prior to initiating the study.

We compared pre- and post-operative data using the AOFAS and EQ-5D questionnaires, clinical reports, and radiological imagery. We also compared the pedobarographic values of our patients with a pool of voluntaries with healthy feet, at minimum 2 years follow-up, using the cohort comparison described by Tsujinaka in 2019, [11] because our gait analysis platform was only available in 2018, therefore we had no preoperative pedobarographic data. At the longest follow up, patient satisfaction regarding cosmetic results and overall satisfaction were analysed using a 0 to 10 scale, respectively a 0 to 100 scale. Patients were also asked if they would recommend the procedure to family or friends.

Surgical technique and postoperative management

The technique used in our centre is a newly developed metatarsal osteotomy called ReveL. It was first developed and described in 2006 by the senior author (PV) and his collaborators [12,13].

All patients were operated on in the supine position under general or spinal anaesthesia. A tourniquet was placed at the thigh. A small medial longitudinal incision of 3-4cm was performed, and the first metatarsal head was exposed after longitudinal medial capsulotomy. A lateral longitudinal capsulotomy was then achieved through the same incision and the plane of the sesamoid bones was released, joining the lateral joint capsule incision. This manoeuvre facilitates the lateral shift of the metatarsal head. The ReveL osteotomy was performed with an oscillating saw. The vertical arm of the osteotomy was placed 1cm proximally from the joint surface and oriented perpendicularly to the axis of the second metatarsal. In a Greek foot configuration (short first ray and overlength of second metatarsal), the vertical arm was oriented slightly distally avoiding a shortening of the first metatarsal. The plantar arm was long and aimed at the plantar cortex of the diaphysis of the first metatarsal head. A medial slide was added to correct the pathological DMAA. The head fragment was then displaced laterally and slightly rotated in varus.

This technique allowed an anatomical realignment of the first metatarsal correcting both the I-II intermetatarsal angle (IMA) and the distal metatarsal articular angle (DMAA) (Figure 1).

Figure 1:The revel correction The metatarso-phalangeal joints approached medially, then the capsule is exposed and longitudinally incised. Care is taken not to injure the cutaneous branch of the superficial peroneal nerve. A reversed L osteotomy is practiced (A). then a wedge osteotomy on the dorsal half of the first metatarsal (B). The small wedge is removed (C). Reduction of DMAA, HVA and IMA by a combination of shift and rotation (D). The planes are fixed with two lags screws €. Resection of the pseudo exostosis (F). Final aspect (G).

The osteotomy was then stabilized with two lag screws (Figure 2). and the pseudo exostosis was resected medially. At this time of the procedure, we simulated a load on the forefoot with the ankle joint in a neutral position. If the tendon of the extensor hallucis longus was not reduced on the first MP-joint, we completed the correction with an Akin osteotomy [14] which was also fixed with a lag screw (Figure 3). It was essential to achieve a perfect osseous alignment of the first ray in order to avoid excessive medical capsulorrhaphy. Finally, capsule closure was performed by single 3.0 monofilament stitches, subcutaneous closure with 4.0 monofilament single stitches and skin closure with a continuous 4.0 polypropylene suture.

Figure 2:

Figure 3:

At the end of the operation elastic dressing was applied, and the patients were allowed to walk with immediate full weight bearing in a flat hard sole shoe for six weeks. Stitches were removed after 2 weeks, and clinical and radiological examination was performed at 6 weeks follow-up. From this time, the patients were allowed to progressively increase their walking distance in a conventional shoe. Physiotherapy with lymphatic drainage and progressive mobilization of the first MTP joint was also prescribed.

Clinical assessment

The clinical assessment was based on patient preoperative files which included a preoperative AOFAS, EQ-5D, VAS scores as well as a detailed physical examination of the foot. These scores were repeated at last follow up.

Radiological assessment

Radiological analysis was based on standing weight-bearing dorsoplantar and lateral radiographs of each entire foot. We measured the Hallux Valgus Angle (HVA), Intermetatarsal Angle (IMA), Distal Metatarsal Articular Angle (DMAA) and lateral shift of the sesamoid bones [15,16].

HVA is measured by drawing a line bisecting the metatarsal shaft and the proximal phalanx of the greater toe. The normal value should not exceed 15 degrees. IMA is determined by measuring the angle performed by 2 lines bisecting the shafts of the first and second metatarsals and the normal value should be less than 9 degrees. DMAA may be evaluated by measuring the angle formed by a line running through the articular edges of the surface of the head and another line bisecting the metatarsal shaft. Its normal value is less than 10 degrees. The sesamoid’s position can be reliably evaluated using the Hardy and Clapham method [11,17,18].

Pedobarographic assessment

Gait analysis was done using the Medicapteur®’s Win-Track® platform and software at a minimum of 2 years after surgery. The Win-Track® platforms dimensions are 1610mm × 652mm × 30mm (length/width/height) (Figure 4). The thickness of the platform is 9mm and is made up of 12,288 sensors of the resistive type. The sensors measure 7.8 × 7.8mm2, and the acquisition frequency of the apparatus is up to 200 images/s. The footsteps of the patients were recorded using this platform and visualized on computer (Figure 5).

Figure 4:

Figure 5:

The plantar aspect of the foot was divided into twelve zones following the lines of Bessou [19,20] (Figure 6), into 1^st ray, 2^nd and 3^rd ray, 4^th and 5^th, and horizontally dividing the foot into toes, forefoot, midfoot and hindfoot (Figure 7).

Figure 6:

Figure 7:

The peak pressure (Peak-P, kPa), contact area (Con-A, cm2) and contact time (Con-T, s) in each region was measured as the rate of the time from heel strike to toe-off. Maximum force (Max-F, N) was deducted from Peak-P and Con-A and the force-time integral (FTI, %) was obtained by calculating a Force time integral. All these values were obtained for each of the 12 zones. The mean values for each region were compared between the 2 groups (study and control).

Statistical analysis

Study data was analysed with Microsoft Excel 2016 (version 24, Chicago, IL), and examined for normality with the student t-test. The priori alpha threshold for statistical significance level was 0.05. Stats kingdom was used for p-value calculation.

Max-F, Peak-P, Con-A, Con-T and FTI were evaluated with a paired t-test. In general, matched pair T-test was applied to the study data to show the effectiveness of the method. For clinical and radiological analysis, we compared pre- and postoperative scores of each patient. After determining the T-values with matched pair T-test, we calculated p values on a one-tail T-distribution.

For the pedobarographic analysis, we compared postoperative footprints of our patients to those of the healthy control group. We used individual two-tail T-tests on all 24 zones, including both left and right feet and took an average of absolute value right and left feet to come up with a single T-score for each zone. The reason we use two-tail T-test for this analysis is that our patients’ data can be on both sides of the control group.

Clinical and radiological results are summarized in (Table 1) and (Table 2). The AOFAS score for the entire study group improved significantly (p < 0.001) with an average increase of 34.65 (SD±13.91) at last follow-up. We found a significant increase in overall range of motion of MP-1 (p > 0.001) with an average increase of 18.79° (SD±16.84).

Table 1:

Table 2:

Table 3:Detailed EQ-5D results.

EQ5D Table 3 showed a lowered score in all dimensions except autonomy which remained unchanged. These results thus show that patients reported increased mobility and capacity to engage in day-to-day activities while experiencing lowered pain, lowered anxiety and had an overall perception of health improvement. VAS was improved by 5.45cm (SD±2.86) (p < 0.001) (Table 1).

Radiographic findings (Figure 8), (Table 2)

HVA of the entire group decreased significantly by 19.52° (SD±8.11) on average (p < 0.0001) and IMA decreased significantly by 8.21° (SD±3.54) on average (p < 0.0001). DMAA also decreased significantly by 17.67° (SD±9.10) on average (p < 0.0001), and sesamoid deviation had been corrected by an average of 3.43mm (SD±1.84) (p < 0.0001).

Figure 8:

As shown in the last column of the table, we obtained p-values smaller than 0.05 for all scores.

Pedobarographic findings (Table 4)

We observed no significant difference, on average, between the control group and our patient group for Max-F, Peak-P, Con-A, Con-T and FTI, meaning pressure pattern observed in operated patients is similar to that of healthy unoperated people.

Table 4a:Graphic of patients and controls average Max F by zone.

Table 4b:Graphic of patients and controls average Peak Pressure by zone.

Table 4c:Graphic of patients and controls average Contact Area by zone.

Table 4bd:Graphic of patients and controls average FTI by zone.

Considering five different parameters, our p-values indicate that we can accept the null hypothesis with a significance level of 0.05 for most of the zones and most of the features. There is no significant difference between the gait analysis of the control group and the HV operated patients comparing the listed parameters for most of the zones.

Subjective results

On a 0 to 10 scale aesthetic average auto-evaluation improved by 5.5 points.

All our patients expressed satisfaction with simultaneous bilateral corrections. On a scale of 0 to 100, average satisfaction reached 90.4. 96.8% of the patients would go through the procedure again under the same conditions and recommend simultaneous operation to family or friends.

Although scientific literature about hallux valgus is abundant, using the PubMed search engine, only 13 articles compare multistaged to simultaneous surgeries. In 2005, Leemrijse et al. [21] mentioned that there was no consensus because of a strong dependence on the surgical technique used. However, in his study, he did not observe a negative impact of simultaneous bilateral surgeries. Regardless of the technique, at least 3 authors indicated that simultaneous bilateral surgeries were safe [22-24], and at least 3 others indicated that the surgical outcome was similar to that of unilateral surgeries [6,25,26]. Regarding cost-effectiveness, estimates seemed to favour of a simultaneous bilateral procedure [24], costs raising from +25% [27] to +75% [20] with a bilateral procedure. Many of these studies were limited by the shortness of the follow up and are difficult to compare due to the variety of surgical techniques used.

In our study, AOFAS improved by an average of 34.65 points, which indicates a clinically important improvement in patients’ functional outcome, according to Chan [28] validating our hypothesis. Moreover, an improvement grade above 30.2 corresponds to a surgery outcome labelled as “good”.

The EQ-5D score showed significant improvement across all axes, except axis 2, representing autonomy and remained unchanged at the highest value. This indicates that the global wellbeing of our patients has been improved by their surgery.

Supporting this trend, all radiological parameters significantly improved, as shown in Table 3., regardless of the severity of the HV case. Unsurprisingly, significant morphological correction was also clearly observed on the radiographs.

The pedobarographic pressure analysis strengthened our hypothesis. In 2017, Hida et al. [29] demonstrated that moderateto- severe HV feet had dysfunction of the great toe during walking. In such feet, Max-F, Con-T, Con-A, and FTI of the great toe were significantly lower than in the healthy feet, whereas Peak-P and Max-F of the central forefoot were significantly higher in the HV feet. Then, in 2019, Tsujinaka et al. [11] demonstrated that the function of the great toe was restored to a level similar to that in healthy subjects after undergoing unilateral proximal crescentic osteotomy. Indeed, significantly similar parameters of the great toe were found in both the operated feet and healthy feet.

Interestingly, it is the case in our post-operative findings: zones 7,8,9,11 and 12 representing the forefoot great and second toe do not significantly differ in both groups, in terms of Max-F, Peak-P, Con-T, Con-A, and FTI (Table 4). meaning that the pressure profile of the forefoot does not differ between the two groups. This shows that our operated patients recover a healthy forefoot pressure profile.

As stated by Puchner [30] the postoperative pressure evolves with time. Therefore, assessment of operated patients must be done once they have reached a steady plateau. A minimum of two years seems correct and supports our decision to determine our minimum follow-up.

Using the Visual Analogue Scale (VAS) [31] to quantify pain, we observed a mean improvement of 54.5mm. According to Todd et al. [32] the smallest clinically significant change in acute pain measured 13mm on a VAS. Our results show that pain, a major complaint, was significantly improved.

The ReveL osteotomy used for all patients in our study, regardless of severity, allowed simultaneous bilateral HV correction. As the surgery occurs on the forefoot, immediate full weight bearing is possible. Proximal osteotomies or Lapidus procedure, on the other hand, do not permit immediate full weight-bearing thereby precluding the possibility of a bilateral simultaneous HV correction. In this matter, our observations resemble Boychenko’s [33] who demonstrated that simultaneous bilateral correction had the same functional and radiographic results as unilateral surgery. His patients underwent a Scarf osteotomy with, in some cases, additional Akin osteotomy. His patients all had lateral soft tissue release and an adductor hallucis tenotomy which is unnecessary with the ReveL technique. Our postoperative management slightly differs since we allow full weight bearing of the whole foot, not only of the heel, on rigid postoperative shoes.

In the present study, the clinical and radiological results of simultaneous bilateral correction by ReveL osteotomy were significantly improved and resemble those reported in previous studies promoting other techniques. We observe diminution of pain and restoration of the function of the great toe.

One of our previous studies compared unilateral and simultaneous bilateral surgeries and has shown no difference in terms of outcome quality, opiate consumption, and recovery time [34]. Thus, in the present study we did not repeat this comparison. It is safe to say that a single simultaneous bilateral procedure is less costly in terms of work incapacity and disability and offers more comfort for the patient since only one operation is required, followed by a unique recovery period.

The main strengths of this study are the careful selection of isolated bilateral hallux valgus cases, all surgeries were performed by the same surgeon using the same technique. Results were very encouraging, and reliable due to our long follow-up. The limitations of our study are due to its retrospective aspect and absence of preoperative pedobarographic data for our patients, we could only compare their postoperative values to those of a group of healthy voluntaries. This method, however, was validated by Tsujinaka and co-authors [32].

Our present study shows significant clinical and radiological improvement at two years follow-up after isolated simultaneous bilateral HV correction using the ReveL osteotomy with or without Akin osteotomy. We could demonstrate that this surgical technique restores anatomy and function of the forefoot in mild to severe HV deformities. Simultaneous correction of both feet improves the comfort of the patient without reducing the quality of the outcome. We therefore recommend and continue performing the ReveL procedure simultaneously whenever possible. Further prospective case studies comparing pre- and postoperative pedobarographic analysis by the same patients must be performed to confirm these results.

B.M.J. and P.V. both supervised this study and should be considered as the last authors.

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