2.1 Materials
In this retrospective study, we collected radiographic data and clinical outcomes from two groups of 90 HV patients (100 feet) with plantar callosities and metatarsalgia between July 2020 and January 2022. All the operations for the HV patients were carried out by two experienced surgeons in our department, all of whom involved one or two headless cannulated compression screws for fixation. The mean follow-up period was 12 months (range, 6-18). The patients were scheduled for surgical treatment if conservative treatment could not relieve the pain and other symptoms or if the deformity affected normal work and life.
All HV patients were approved by the Ethics Committee of the Third Hospital of Hebei Medical University before surgery. The inclusion criteria and exclusion criteria of this study were as follows: bunion inflammation, HVA ≤ 40 degrees, IMA ≤ 16 degrees, and mild to moderate HV with a mismatched first metatarsal-toe joint [9]; and calcaneal malformations, neurological disorders, rheumatoid arthritis, gout, or a history of HV corrective surgery. Information about the plantar calloses, metatarsalgia, radiological data, and complications was obtained from the patient's foot, radiographs, and recordings.
We classified the plantar callosities according to their number, scope, and degree of pain, and their areas were measured before and after surgery with a ruler using the following formula: length (L)×width (W) (cm2) (Fig. 1).
The grading method used in this study was derived from Nakagawa et al. [10]: grade 0, no plantar callosities; grade 1, painless plantar callosities; grade 2, plantar callosities below 1 MTPJ with pain; and grade 3, plantar callosities under 2 or more MTPJs with pain (Fig. 2).
If the patient walked barefoot, pain in the forefoot area was recorded as metatarsalgia. Thirty-one patients in the TCO group and 32 patients in the CO group had metatarsal pain accompanied by plantar callosities. The preoperative data of the patients are shown in Table 1.
Table 1. Preoperative data of the included patients
Variables
|
Feet (patients)
|
P value
|
TCO = 50 (45)
|
CO = 50 (45)
|
Age, years
|
52 ± 13.42 (range 24-76)
|
51.53 ± 15.03 (range 16-80)
|
0.876
|
Age groups (n)
|
|
|
|
20~30 years
|
5
|
4
|
|
30~40 years
|
5
|
7
|
|
40~50 years
|
7
|
7
|
|
51 years or more
|
28
|
27
|
|
Hallux valgus severity
|
|
|
|
HVA
|
|
|
|
Mild (< 20°)
|
17 (17)
|
18 (18)
|
|
Moderate (>20°&≤40°)
|
33 (28)
|
32 (27)
|
|
Severe (> 40°)
|
0
|
0
|
|
IMA
|
|
|
|
Mild (≤13°)
|
17 (17)
|
18 (18)
|
|
Moderate (>13°&≤16°)
|
33 (28)
|
32 (27)
|
|
Severe (>16°)
|
0
|
0
|
|
Sex (M:F)
|
5:40
|
7:38
|
|
Callosity area (cm2)
|
6.43 ± 2.53
|
6.66 ± 1.31
|
0.580
|
Plantar callosity grade (an)
|
|
|
|
Grade 0
|
7
|
8
|
|
Grade 1
|
12
|
10
|
|
Grade 2
|
16
|
18
|
|
Grade 3
|
15
|
14
|
|
Metatarsalgia (n)
|
31
|
32
|
0.836
|
Abbreviations: hallux valgus angle (HVA); intermetatarsal angle (IMA)
The severity of the hallux valgus deformity was classified by the HVA and IMA (mild: HMV< 20°, IMA≤13°, moderate: 20°<HMV≤40°, 13°<IMA≤16°, severe: HMV> 40°, IMA>16°) [11].
a Grading for plantar callosities: grade 0, no plantar callosities; grade 1, painless plantar callosities; grade 2, painful callosities below 1 MTPJ; grade 3, painful callosities below 2 or more MTPJs.
2.2 Surgical technique
All surgeries were performed by an experienced orthopaedic podiatrist in our department. During these surgical procedures, an ankle tourniquet was used above the ankle under local anaesthesia. We started by making a straight midline medial skin incision. Then, a transverse incision was made at the first metatarsophalangeal joint, exposing the MTPJ capsule, and the mediodorsal and plantar cutaneous nerves were identified and protected. Next, the medial eminence of the first metatarsal head was excised parallel to the sagittal sulcus; soft-tissue release was usually performed through a separate dorsal incision between the first and second metatarsal bones, along with an incision of the ligament and the lateral joint capsule, to release the deep transverse metatarsal ligament. In all cases, the apex of the osteotomy (TCO & CO) was located in the centre of the first metatarsal bone, approximately 5-7 mm from the articular surface, and the osteotomy was oriented towards the fourth MPTJ. In the CO group, a 60° V-shaped metatarsal osteotomy was then performed (Fig. 3). The lateral translation of the distal metatarsal osteotomy was 5-8 mm. In contrast to CO, TCO improved the angle of the osteotomy plane. First, during the 60° Chevron osteotomy, the osteotomy line near the bottom was tilted 20° towards the sole (POCO), followed by a dorsal osteotomy with a 10° tilt to the distal metatarsal head (Fig. 4). The plantar and distal cut resulted in relatively long osteotomy lines, which play an important role in reducing the height and lengthening the length of the first metatarsal. To correct the valgus deformity, lateral displacement of the distal metatarsal fragments should not exceed 50% of the width of the metatarsal [12]. The osteotomy line was fixed using one or two headless cannulated compression screws. After DCMO and soft-tissue release surgery, there were still 15 residual malformations in both groups, which were corrected at approximately 7 mm of the proximal phalangeal bone by the Akin procedure. Finally, part of the medial capsule of the MTPJ was excised before capsulorrhaphy (as part of soft-tissue balancing). The soft tissue was sutured in a conventional pattern.
2.3 Postoperative rehabilitation
A 5 cm-wide elastic bandage was applied postoperatively to keep the MPTJ in a corrected position. After no bleeding from the incision, the patient was encouraged to walk with partial weight-bearing using a hard-soled shoe. The stitches were removed after two weeks. In this postoperative period, MTPJ motion exercises were started to achieve a full range of movement. In addition, the Kirschner wires were removed approximately 5-6 weeks postoperatively after radiographs confirmed bone healing. Approximately 8 weeks after surgery, most patients were able to wear some of their soft shoes with full weight-bearing. Then, 12 weeks after surgery, the patients were allowed to return to regular sports activities to improve joint motion, strength, and balance.
2.4 Outcome measures
2.4.1 Radiographic measurement
Ninety female and male patients in the two groups (TCO: age range 24-76 years; CO: age range 16-80 years) were evaluated. The HVA, IMA, and DMAA were measured according to standard weight-bearing anterior and posterior radiographs [13]. For postoperative measurements, we used the head centre technique and the metaphyseal-diaphyseal reference point [14]. Since the lateral radiographs inevitably showed visual disturbances in all five metatarsals, we measured the first metatarsal length (FML), that is, the distance from the proximal subchondral midpoint to the distal subchondral midpoint of the articular surface of the first metatarsal bone [15], on pre- and postoperative anteroposterior, nonweight-bearing foot radiographs (Fig. 5). The height of the second metatarsal head (SMHH) was defined as the perpendicular distance from the second metatarsal head to the line connecting the lowest point of the first and fifth metatarsal heads on the weight-bearing X-ray (Fig. 6). The paired T test was used to compare pre- and postoperative data. Changes in the FML and SMHH between the TCO and CO groups were compared.
2.4.2 Clinical evaluations
The American Orthopaedic Foot & Ankle Society (AOFAS) Hallux score [16] and visual analogue scale (VAS) score were recorded preoperatively and postoperatively to evaluate the clinical outcomes of the HV patients. Additionally, the changes in the area and grade of the callosities before and after surgery, as well as the change in the number of patients with metatarsalgia, were recorded in the two groups. Statistical analysis and comparison of the parameters within and between the two groups were performed. Complications such as infection, malunion, nonunion, metatarsal head avascular necrosis, recurrence of hallux valgus, and hallux varus were also collected. During follow-up, we also considered patients' self-reported subjective satisfaction with pain relief, function, and appearance. The results were graded as excellent, good, average, and poor.
2.5 Statistical analysis
The statistical analysis was performed using SPSS Statistics 18.0 (Version 18, IBM, Armonk, NY, USA). The HV parameters are reported as the means and standard deviations. First, we compared preoperative and postoperative radiological parameters within and between the TCO and CO groups and assessed whether their differences were statistically significant. Then, the change in plantar callosity grading and area value before and after DCMO between the TCO and CO groups was compared, and we assessed whether there was a significant difference between the two groups. Similarly, the clinical AOFAS and VAS scores were compared pre- and postoperatively within and between the two groups. Preoperative data and postoperative outcomes were compared using the parametric t test, Pearson’s chi-square test, and the Mann‒Whitney U test. A p value < 0.05 was considered statistically significant.