Flatfoot is defined as loss of medial arch with hindfoot valgus, but normal condition is obscure due to wide individual variance. Loss or decreasing of medial longitudinal arch with radiographic image is clinically diagnosed as flatfoot. Flatfoot without symptoms is not an indication for treatment. The etiologies of flatfoot are congenital cause, hypermobility, tarsal coalition, neuromuscular disease, post-traumatic deformity, Charcot arthropathy, and posterior tibial tendon dysfuction. The flatfoot is classified as congenital and acquired, flexible, and rigid. The diagnosis is made by physical examination and radiographic findings. In particular, the posterior tibial tendon dysfunction is known as adult acquired flatfoot.

Flatfoot deformity, defined as loss of medial longitudinal arch, sometimes involves symptoms such as medial arch pain or Achilles tendon tightening, etc. Whether the etiology of deformity is congenital or acquired, i.e., posterior tibial tendon dysfunction, symptoms are largely resolved with conservative treatment including medication, orthoses, and activity modification. Surgery should be considered in cases of failure of conservative treatment and clinicians can select an appropriate technique among many surgical options including calcaneal osteotomy or flexor digitorum longus tendon transfer. Principles of corrective surgery include the recovery of alignment and the preservation of joint motion.

Purpose: The purpose of this study is to review the indications of ankle lateral complex reconstruction using tendon graft. Materials and Methods: We searched PubMed using the index, "ankle, instability, lateral ligament, reconstruction" from 1990 to present (September 30, 2015). We excluded 1) modified Brőstrom operation (MBO), 2) conventional tenodesis surgery, 3) review article, 4) technical note, and 5) articles written in another foreign language. We reviewed 24 papers through the publication events, operational method, the indications of surgery, and the specific features of the patient group. Results: There were the indications of 1) previous ligament surgery failure, 2) situation when ligament repair is impossible due to the ligament defect, 3) severe instability (preoperative talar tilt >$15^{\circ}$, anterior draw >10 mm or the difference of contralateral side talar tilt >$5^{\circ}$, anterior draw >3 mm), and 4) overweight (body mass index >$30kg/m^2$). Other considerations included 1) generalized joint laxity and 2) workers, highly-demanded or athlete highly-affected by instability. Conclusion: The ankle lateral complex reconstruction using tendon graft could be indicated in patients with the possibility of MBO failure with several considerations.

Purpose: We compared the results of total ankle arthroplasty in patients with preoperative varus deformity of more than $20^{\circ}$ with those of patients with varus deformity less than $20^{\circ}$. Materials and Methods: From January 2005 to January 2013, 9 ankles with preoperative varus deformity of more than $20^{\circ}$ (varus group) and 31 ankles with varus deformity less than $20^{\circ}$ (control group) underwent total ankle arthroplasty. Clinical results were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score, and radiographic results were assessed using tibiotalar varus angle in standing anteroposterior radiographs taken preoperatively and at the last follow-up. Results: The mean duration of clinical follow-up was 42.8 months (14~60 months). The AOFAS score was improved by a mean 47.0 points in the varus group and 37.6 points in the control group. Statistically significant difference was observed between the two groups (p=0.041). Tibiotalar varus angle measured at the last follow-up radiograph was $2.5^{\circ}$ in the varus group and $1.0^{\circ}$ in the control group and the difference was not statistically significant (p=0.820). Conclusion: Satisfactory clinical and radiographic results can be achieved in patients with varus deformity more than $20^{\circ}$ by precise bone resection and soft tissue release.

Purpose: Nerve conduction study (NCS) test is a standard diagnostic study of the tarsal tunnel syndrome. The purpose of this study was to determine the relation between the results of the NCS and postoperative clinical results. Materials and Methods: From June 2004 to July 2015, 104 patients were diagnosed with tarsal tunnel syndrome and treated surgically. Of 104 patients diagnosed through NCS preoperatively and postoperatively, 41 patients were included in this study. There were 23 male and 18 female patients with mean age of 49.2 years old and the average follow-up period was 15.5 months. NCS, pain visual analogue scale (VAS) score, and subjective satisfaction were examined preoperatively and postoperatively. Results: On the preoperative NCS, 32 patients (78.0%) were positive and 9 patients (22.0%) were negative, and 32 positive NCS patients consisted of 9 positive (28.1%), 16 improved (50.0%), and 7 negative (21.9%) postoperatively. VAS score was 7.4 preoperatively and 4.4 postoperatively. According to satisfaction, there were 8 excellent (19.5%), 21 good (51.2%), 6 fair (14.6%), and 6 poor (14.6%) patients. For 32 patients who were positive on the preoperative NCS, the postoperative VAS score was 4.87 and there were 7 excellent (21.9%), 16 good (50.0%), 4 fair (12.5%), and 5 poor (15.6%) patients. Sixteen patients were negative on the postoperative NCS, with a VAS score of 3.75, 1 excellent (6.3%), 11 good (68.8%), 2 fair (12.5%), and 2 poor (12.5%). There was no statistical correlation between the preoperative NCS and postoperative VAS score (p=0.10), between preoperative NCS and postoperative satisfaction (p=0.799), between preoperative NCS and postoperative VAS score (p=0.487), and between postoperative NCS and postoperative satisfaction (p=0.251). Conclusion: For patients diagnosed with tarsal tunnel syndrome and treated surgically, NCS showed little correlation with postoperative result.

Purpose: Several techniques have been introduced for correction of pes cavo-varus deformity. We retrospectively reviewed and compared the data of patients who underwent 1st metatarsal osteotomy alone, Dwyer's osteotomy alone, and 1st metatarsal osteotomy combined with Dwyer's osteotomy to determine the effect on radiographic parameters. Materials and Methods: Data on 28 cases in 27 consecutive patients recruited from 2006 to 2014 who underwent 1st metatarsal osteotomy alone (group F), Dwyer's osteotomy alone (group H), or 1st metatarsal osteotomy followed by Dwyer's osteotomy (group HF) with a minimum 1-year follow-up were reviewed retrospectively. Results: Calcaneal pitch angle on the standing foot lateral radiographs was significantly decreased after the operation in groups H and HF whereas Meary angle was decreased in groups F and HF. Hindfoot alignment angle and ratio on the hindfoot alignment view were improved in groups H and HF. Maximal medial cuneiform height reduction was observed in group HF. 1st ray was significantly shortened in groups F and HF. Conclusion: Combined forefoot and hindfoot operation took the largest correction power of all radiologic parameters.

We reported on a rare case of recurred macrodystrophia lipomatosa of the foot, and reviewed the literature. A 62-year-old male patient presented with right foot second toe pain; preoperative magnetic resonance imaging and radiograph examination was performed. After surgery the biopsy confirmed the diagnosis. American Orthopaedic Foot and Ankle Society score was checked before and after surgery. Wide excision of the affected area including ray amputation is an effective way to prevent recurrence and relieve the pain after surgery. The 2nd toe ray amputation was performed in the treatment of recurred macrodystrophia lipomatosa of the foot, and is thought to be an effective way to relieve pain and prevent recurrence. After minimally invasive surgery with complete excision surgery, additional data on recurrence and pain relief rate are needed.

Tarsal coalition is an abnormal union between two or more bones of the hind- and mid-feet, which can occur at various rates from cartilaginous to osseous union. Talonavicular coalition is reported less frequently than calcaneonavicular or talocalcaneal coalition and has been associated with various abnormalities, including symphalangism, clinodactyly, ray anomaly, clubfoot, other tarsal coalitions, and a ball-and-socket ankle joint. Patients with talonavicular coalitions are usually asymptomatic and rarely require surgical treatment. We review the literature and report on a case of 59-year-old male patient with talonavicular coalition.

Achilles tendon rupture is thought to be increasing with participation in sports activities. Both operative and non-operative treatments of Achilles tendon rupture include a period of immobilization. Complications following treatment of the Achilles tendon rupture include recurrence of rupture, flexor weakness, infection, and wound problems. However, deep vein thrombosis (DVT) after operative treatment of the Achilles tendon has not been reported. We report on a case of DVT after Achilles tendon repair.

Development of a pseudoaneurysm around the ankle is an uncommon complication after surgery. We experienced a case of a pseudoaneurysm, which developed from the anterior tibial artery. A 44-year-old woman had sustained painful swelling of her right ankle after the removal of implants for a distal fibular fracture. The pseudoaneurysm was confirmed by ultrasonography and angiography. The patient was treated with an intervention using a coil and recovered without further complaints. This case report aims to increase the awareness of this complication with review of literature.

Spontaneous rupture of the extensor tendon has been reported in association with predisposing inflammatory conditions including rheumatoid arthritis, diabetes, trauma, tophaceous gout, and steroid injection. The authors experienced a case of spontaneous rupture of the extensor digitorum longus tendons caused by an osteophyte of the tarsometatarsal joint in a patient with rheumatoid arthritis. The authors stress that aggressive treatment including surgery could be considered for prevention of spontaneous tendon rupture in a patient with predisposing conditions despite an asymptomatic spur.

We report on a rare case of an intraosseous epidermoid cyst in the distal phalanx of the great toe with concurrent infection in a 71-year-old woman with diabetes mellitus. The lesion was initially considered simple infectious arthritis and concomitant osteomyelitis in a patient with diabetes. However, after surgery, an intraosseous epidermoid cyst originating from the nail bed and involving the articular surface of the distal phalanx was detected. The epidermoid cyst may have contributed to the infectious arthritis in the interphalangeal joint. The lesion was treated via mass excision, arthrotomy, debridement, and intravenous antibiotics.