Transmetatarsal Amputation Results in Higher Frequency of Revision Surgery and Higher Ambulation Rates Than Below-Knee Amputation.

Background: Selecting the level of amputation for patients with severe foot pathology can be challenging. The surgeon is sometimes confronted with an option between transmetatarsal amputation (TMA) and below-knee amputation (BKA). Recent studies have suggested that minor foot amputations have high revision rates and need for higher level of amputation. This study sought to compare the revision rates, need for higher level of amputation, postoperative ambulatory rate, and the demographic factors between these 2 operations. Methods: We retrospectively reviewed the records of patients undergoing either BKA or TMA at a single academic institution during an 8-year period. Demographic characteristics and medical history were collected and included in a binary logistic regression model to evaluate for independent predictors of needing revision surgery or needing higher-level amputation. Secondary outcomes included ambulatory status and wound status at last follow-up. Results: There was a total of 367 patients who underwent either BKA (n=293) or TMA (n=74).On binary logistic regression, the only significant independent predictor of needing revision surgery was undergoing TMA (odds ratio [OR] 2.30, CI 1.199-4.146, P = .011). The presence of PAD trended toward significance (OR 2.12, CI 0.99-4.493, P = .051). Similarly, significant independent predictors of needing higher level amputation were undergoing TMA (OR 4.117, CI 1.9-8.9, P < .001) and presence of PAD (OR 4.85, CI 1.59-14.85, P = .006). More TMA patients were ambulatory (56.8%) on last follow-up compared with BKA patients (30.9%). Conclusion: Transmetatarsal amputation has a higher risk of reoperation and need for revision amputation compared with below-knee amputation. Transmetatarsal amputation has a higher chance of returning patients to independent ambulation. Patients with peripheral arterial disease are at a higher risk of revision surgery and higher-level amputation with both operations. Level of Evidence: Level III, retrospective case review.

An Anatomic Study of the Lateral Dorsal Cutaneous Nerve Using 3-Tesla MRI: A Comparison to Cadaveric Data With Surgical Applications.

BACKGROUND: The lateral dorsal cutaneous nerve (LDCN) and the anastomotic branch of the sural nerve (AB) are cutaneous sensory nerves at risk of iatrogenic injury during lateral foot surgery. This study is the first to use a large cohort of high-resolution magnetic resonance images (MRIs) of the ankle to better describe the course of these nerves in vivo in order to aid surgeons intraoperatively. Our study intends to build on the "high and inside" approach to the proximal 5MT by accounting for variations in course of the LDCN and AB. METHODS: One hundred twenty-five 3-tesla (T) MRI studies of the ankle were analyzed. Three reviewers measured the distance from the LDCN and AB to landmarks including the most proximal aspect of the fifth metatarsal tuberosity (5MT) and the peroneus brevis tendon (PBT). RESULTS: Mean vertical distance from the LDCN to the 5MT was 0.8 ± 0.2 cm. Presence of an AB was visualized in 59 of 125 studies (47.2%) and was found 2.2 ± 0.5 cm dorsal to the 5MT. The AB was found to become superior to PBT at a horizontal distance 1.9 ± 0.5 cm proximal to the 5MT. The LDCN was found superior to the PBT at its insertion onto the 5MT in approximately 10% (n = 12) of our studies. During these instances, the LDCN was located an average of 0.3 cm dorsal to the PBT. CONCLUSION: Our proposed "safe zone" for the approach to the proximal 5MT remains superior to the LDCN and inferior to the AB and avoids crossing directly over either nerve in >95% of analyzed MRI studies. This incision begins 1.5 cm dorsal to the most proximal aspect of the 5MT and extends no more than 1 cm posteriorly. Careful dissection and identification of the LDCN and possible AB is necessary prior to further extension of incision. LEVEL OF EVIDENCE: Level IV, case series.

Quality Assessment of Modern Total Ankle Arthroplasty Clinical Outcomes Research.

Research demonstrating improved outcomes with third-generation ankle replacement implants has resulted in increasing utilization of total ankle arthroplasty over the past 3 decades. The purpose of this study was to examine the quality and trends of clinical outcomes research being published on third-generation total ankle arthroplasty implants. Two fellowship-trained foot and ankle surgeons reviewed all peer-reviewed, Medline-indexed English-language clinical outcomes studies evaluating total ankle arthroplasty published between 2006 and 2019. Articles were assessed for study design and indicators of study quality. A total of 694 published articles were reviewed and 231 met all inclusion criteria. The majority (78%) of studies were retrospective, most of which were case series (54%) or cohorts (32%). Ten percent (10%) of studies were funded by industry and 28% did not disclose funding sources. Thirty-eight percent (38%) of studies reported a conflict of interest and 6% did not disclose whether or not there were conflicts. The average patient follow-up time across studies was 72 months. We found that although the study of outcomes with third-generation total ankle arthroplasty prostheses is steadily increasing, most studies are Level IV, retrospective case series. Some studies have disclosed industry funding and/or a conflict of interest, and a considerable number did not disclose potential funding and/or financial conflicts. Future investigators should strive to design studies with the highest quality methodology possible.

An Anatomic Study of the Sural Nerve Using 3-Tesla MRI: A Comparison to Cadaveric Data With Surgical Applications.

BACKGROUND: The sural nerve (SN) is a sensory cutaneous nerve that is at risk of iatrogenic injury during surgery at the lateral ankle. Prior anatomic studies of the SN are limited primarily to cadaveric studies with small sample sizes. Our study analyzed a large cohort of magnetic resonance images (MRIs) of the ankle to obtain a more generalizable, in vivo sample of distal SN course. METHODS: A total of 204 3-tesla MRI studies of the ankle were analyzed. Three reviewers measured the distance from the SN to various landmarks including the distal tip of the lateral malleolus (DTLM) and the lateral border of the Achilles tendon (LBA). RESULTS: Mean vertical distance from SN to DTLM was 2.2 cm (range, 0.9-3.6 cm). Mean horizontal distance from SN to DTLM and to LBA at the level of DTLM was 1.7 cm (range, 0.8-3.0 cm) and 1.9 cm (range, 1.0-2.9 cm), respectively. Mean horizontal distance from SN to LBA at the level of superior Achilles tendon insertion onto the calcaneus (SAI) was 2.6 cm (range, 1.4-3.7 cm), and mean horizontal distance from SN to LBA at 5 cm above SAI was 0.9 cm (range, 0.4-1.8 cm). CONCLUSION: The variation in SN course observed in our study allowed us to propose "safe zones" for several surgical approaches including the extensile lateral approach to the calcaneus (ELAC), the sinus tarsi approach (STA), the direct lateral approach to the lateral malleolus (DLA), and the posterolateral approach to the ankle (PLA), which we hope will minimize iatrogenic injury to the SN. LEVEL OF EVIDENCE: Level IV, case series.

Lateral Locking Plate Fixation of Simple Weber B Fibula Fractures Without a Lag Screw Yields Excellent Radiographic Results.

BACKGROUND: The most common first-line fixation technique for simple Weber B fibula fractures is a lag screw with lateral neutralization plate. The most common surgical technique for unstable Weber B fibula fracture is one-third semi-tubular plate and cortical screws, implemented with lag screw when appropriate. However, the lag technique can be technically challenging in osteoporotic bone or within fibulas of smaller diameter, and in some cases can result in fragmentation at the fracture site, malreduction, or peroneal irritation. The purpose of this study is to examine an alternative first-line method for routine treatment of simple Weber B fibula fractures. METHODS: Fifty-two consecutive patients undergoing open reduction internal fixation (ORIF) of a Weber B fibula fracture by a single surgeon were included in this retrospective study. After reduction, a lateral locking plate was applied with cortical screws proximally and locking screws distally. No screw crossed the fracture in any case. Per published precedent, nonunion was defined as either a gap of >3 mm between fracture surfaces >6 months postoperatively or a fracture line >2 to 3 mm wide and sclerosing of the fracture surfaces. Similarly, malunion was defined as one or more of the following: talar tilt >2º, talar subluxation >2 mm, or tibiofibular clear space ≥5 mm. RESULTS: The mean (± standard deviation) age of the 52 included patients was 44.2 ± 16.2 years, the mean body mass index was 27.7 ± 6.6 kg/m2, and 63.5% of patients identified themselves as female sex. The mean follow-up was 6.2 (range: 1.5-15) months. In addition to undergoing fixation of the lateral malleolus, 21 patients also underwent fixation of the posterior malleolus, 27 underwent fixation of the medial malleolus, 29 underwent fixation across the syndesmosis, and 7 underwent repair of the deltoid. In all patients, bony anatomic union of the fibula and congruence of the mortise were achieved with no cases of malunion or nonunion. CONCLUSIONS: The Arbeitsgemeinschaft für Osteosynthesefragen (AO) fixation technique for simple Weber B fractures with a lag screw and lateral neutralization plating has provided good outcomes for decades. We present an alternative technique for ORIF of these fractures with a lateral locking plate and no lag screw. In our series, we evaluated radiographic union and alignment as our primary outcome measures and found no cases of nonunion or malunion. Prospective cohort testing of lateral locking plates versus traditional fixation in the context of patient-centered value is warranted.Level of Evidence: Level III.

Use of Small-Pin Distraction and Low-Speed, High-Torque Burring for Talar Osteochondral Allografts: Technique Tip.

Level of Evidence: Level V, expert opinion.

Technical Tip Kerfing for Lapidus Arthrodesis: Deformity Correction With Minimal Bone Resection.

The Lapidus arthrodesis can be a powerful but technically challenging procedure. Common pitfalls include gapping at the arthrodesis site, shortening, and residual malalignment. Herein is described a simple and reproducible technique to obtain a congruent arthrodesis site with excellent deformity correction and minimal bone loss by the use of joint kerfing.

Radiographic Impact of Lapidus, Proximal Lateral Closing Wedge Osteotomy, and Suture Button Procedures on First Ray Length and Dorsiflexion for Hallux Valgus.

BACKGROUND: Shortening and dorsiflexion of the first metatarsal are known potential side effects of metatarsal osteotomies for hallux valgus (HV) with the potential to cause transfer metatarsalgia. We compared the effect of the first tarsometatarsal joint arthrodesis (Lapidus procedure), proximal lateral closing wedge osteotomy (PLCWO), and intermetatarsal suture button fixation procedures on the length and dorsiflexion of the first ray. METHODS: We retrospectively evaluated 105 feet in 99 patients with 30 weeks of follow-up. The average age was 54 years. Seventy-four feet had a Lapidus procedure, 12 had a PLCWO, and 19 had intermetatarsal suture button fixation. Digital radiographic measurements were made for the pre- and postoperative hallux valgus angle (HVA) and intermetatarsal angle (IMA), absolute and relative shortening of the first ray, and dorsiflexion. RESULTS: Preoperative HVA and IMA did not differ between treatment groups (P > .05 for each). Similar corrections of HVA (30.5-13.5 degrees) were achieved between all groups (P > .05). The IMA was improved more in the Lapidus group (14.3-6.5 degrees) compared with the suture button fixation group (14.2-8.1 degrees) (P = .045). There were significant differences in the change in absolute first cuneiform-metatarsal length (FCML) between the Lapidus (-1.6 mm), PLCWO (-2.3 mm), and intermetatarsal suture button fixation (+1.9 mm) procedure (P = .004). There were also significant differences in relative first metatarsal shortening between the Lapidus (0.1 mm relative shortening), PLCWO (1.1 mm relative shortening), and intermetatarsal suture button fixation (1.3 mm lengthening) procedure (P < .001). The average dorsiflexion differed between the Lapidus (1.8 degrees) and suture button fixation (0.4 degrees) groups (P = .004). CONCLUSION: Intermetatarsal suture button fixation relatively lengthened the first ray, the Lapidus procedure maintained length, and the PLCWO relatively and absolutely shortened it. Dorsiflexion may be higher with the Lapidus and osteotomy procedures. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Talar Osteonecrosis After Subchondroplasty for Acute Lateral Ligament Injuries: Case Series.

Talar osteonecrosis is a well-described phenomenon following talar neck fracture, but is a rarely described complication after procedures about the foot and ankle. Here we describe the clinical course of 5 cases of talar osteonecrosis following injection of calcium phosphate into the talus (subchondroplasty) with or without acute lateral ligament repair after acute lateral ankle ligament injuries performed at an outside institution. Practitioners should be aware of this potentially devastating complication. Future research is indicated to determine the safety and efficacy of subchondroplasty for the talus. LEVEL OF EVIDENCE: Level V, case series.

Impact of Coleman Block Test on Adult Hindfoot Alignment Assessed by Clinical Examination, Radiography, and Weight-Bearing Computed Tomography.

BACKGROUND: Cavovarus foot constitutes a complex 3-dimensional deformity. The Coleman block test has traditionally been used to distinguish between forefoot- and hindfoot-driven deformity. However, there has been no objective evaluation of the Coleman block test using radiographs or weightbearing computed tomography (WBCT). The purpose of this study was to compare hindfoot alignment in adult cavovarus feet with and without the Coleman block using clinical examination, radiography, and WBCT. METHODS: Six feet in 6 patients with a clinical diagnosis of cavovarus foot deformity were prospectively enrolled. All feet underwent clinical photography with the camera positioned at 0 degrees to the heel, hindfoot alignment view radiography with the beam positioned 20 degrees off the ground, and WBCT, both with and without the Coleman block in place. Clinical photos were characterized using the standing talocalcaneal angle (STCA), radiographs were characterized using the hindfoot alignment angle (HAA), and WBCTs were characterized using manual and automated hindfoot alignment angle (HAA) and foot and ankle offset (FAO). Using paired analyses, measurements taken with the Coleman block in place were compared to those taken without the Coleman block. Finally, the different methods of measuring hindfoot alignment were tested for correlation with each other. Mean age was 56 years (range 38-69). RESULTS: On clinical photography, the STCA decreased by 3.8 degrees with addition of the block (from 10.0±6.6 degrees varus without block to 6.2±7.1 degrees varus with block; P = .001). On radiograph, HAA decreased by 9.0 degrees with addition of the block (from 16.8±8.4 degrees varus without block to 7.5±6.3 degrees varus with block; P = .07). On WBCT, hindfoot alignment angle changed an average of 3.2 degrees (33.4 degrees varus without block, 30.2 degrees varus with block; P = .008). On WBCT, FAO decreased by 1.4% (from 11.3% varus without block to 10.1% varus with block; P = .003). Clinical examination and automated WBCT measurements were strongly correlated with each other. CONCLUSION: Clinical examination, radiograph, and WBCT demonstrated improvements in hindfoot varus using the Coleman block test in adults, but no patient demonstrated complete resolution of deformity regardless of the measurement modality. Clinical examination correlated strongly with automated WBCT measurements. LEVEL OF EVIDENCE: Level IV, retrospective case review.

Native paraneurial tissue and paraneurial adhesions alter nerve strain distribution in rat sciatic nerves.

Paraneurial adhesions have been implicated in the pathological progression of entrapment neuropathies. Surgical decompression of adhesions is often performed, with the intent of restoring nerve kinematics. The normal counterpart of adhesions, native paraneurium, is also thought to influence nerve deformation and mobility. However, influences of native or abnormal paraneurial structures on nerve kinematics have not been investigated. We measured regional strains in rat sciatic nerves before and immediately after decompression of native paraneurial tissue, and before and after decompression of abnormal paraneurial adhesions, which formed within 6 weeks of the initial decompression. Strain was significantly higher in the distal-femoral than in the mid-femoral region of the nerve before either decompression. Decompression of native and abnormal paraneurial tissue removed this regional strain difference. Paraneurial tissues appear to play a major role in distributing peripheral nerve strain. Normal nerve strain distributions may be reconstituted following decompression, even in the presence of paraneurial adhesions.