Anatomic Structures at Risk When Utilizing an Intramedullary Nail for Distal Fibular Fractures

Category: Ankle Introduction/Purpose: Distal fibula fractures are most commonly fixated with plate and screw constructs. Conversely, modern generation fibular intramedullary nails are load-sharing devices that offer rigid internal fixation via percutaneous technique with only transaxial screws residing subcuticularly. The relative risk of damage to nearby structures is well characterized for plate and screws constructs; however, no such data is available for fibular nails. As a result, the purpose of this anatomic study was to assess the relative risk to nearby anatomic structures when implanting a current generation retrograde locked intramedullary fibular nail. Methods: This was an IRB-exempt study. Ten human cadaveric lower extremities were instrumented with a contemporary retrograde locked intramedullary fibular nail with three distal locking and two syndesmotic fixation options. The cadavers were then dissected by a single experienced orthopedic foot and ankle surgeon in a standardized fashion. The shortest distance, in millimeters (mm), between the site of procedural steps and nearby named structures of interest (i.e. sural nerve, superficial peroneal nerve and the peroneal tendons) was measured and recorded. Levels of risk were then assigned based on observed distances as high (0 to 5 mm), moderate (5.1 to 10 mm) and low (greater than 10 mm). Results: The peroneus brevis tendon was at high risk when making the distal skin incision in all specimens (Table). When reaming and inserting the nail through the distal fibula aperture, the peroneus brevis was at high risk in 7 specimens. The peroneus longus tendon was at moderate to high risk when inserting both the proximal and distal syndesmotic screws in 9 specimens. The superficial peroneal nerve was at high risk when inserting an anterior to posterior distal locking screw in 7 specimens. The sural nerve was at low risk for all procedural steps. Of note, no structures were observed to have been directly damaged. Conclusion: The current findings indicate that strict adherence to sound percutaneous technique is needed in order to minimize iatrogenic damage to neighboring structures when performing retrograde locked intramedullary fibular nail insertion. This includes making skin-only incisions, thorough blunt spreading down to bone, and maintaining close approximation between tissue protection sleeves and bone at all times. The current findings indicate that the peroneal tendons and superficial peroneal nerve are at the highest risk, and should be considered when performing relevant clinical outcomes studies

Structures at Risk with Plantar Approach Retrograde First Metatarsal Charcot Beam Screw Insertion

Category: Diabetes, Midfoot/Forefoot Introduction/Purpose: The plantar approach for medial column retrograde intramedullary fixation of Charcot midfoot deformity allows for easy access to the ideal starting point on the metatarsal head and is supported by good clinical outcomes data. The primary argument against this approach is iatrogenic damage to the plantar structures of the metatarsophalangeal joint (MTP), which could cause tendon imbalances resulting in hallux malleus deformity. However, thus far, such complications have rarely been reported. Based on available literature, it is unclear what types of plantar structure injury occur and at what frequency. The purpose of this study was to describe plantar first metatarsophalangeal joint structure damage caused by plantar approach retrograde intramedullary medial column beam fixation. Methods: This was an IRB-exempt study. For each of 10 human cadaveric specimens, a 6.5 mm cannulated screw system was used for plantar approach retrograde medial column intramedullary fixation. This entailed using fluoroscopy to percutaneously localize a 2.8-millimeter (mm) guide wire to the center-center position on the first metatarsal head and then advanced it into the center of the medial cuneiform. A small sagittal plane skin incision was made around the wire and subcuticular tissue was bluntly divided. Next, a 4.8-mm cannulated drill was passed through a drill sleeve over the wire. Then, a countersink was used without a tissue protector. Finally, the 6.5-mm screw was inserted until it was recessed beneath subchondral bone. The specimens were then dissected to evaluate damage to the plantar structures of the 1st MTP joint. Damage to named structures was categorized as none, less than 50%, greater than 50%, and 100%. Results: The plantar plate was less than 50% damaged in all specimens. The flexor hallucis longus (FHL) tendon had less than 50% damage in 8 specimens. In one of two specimens with greater than 50% FHL damage, the torn portion of the tendon was tenodesed to the first metatarsal head by the screw (Figure). Although the medial flexor hallucis brevis (FHB) tendon was less than 50% damaged in 3 specimens and undamaged in the remainder, the medial sesamoid was less than 50% damaged in 8 specimens. In contrast, less than 50% damage occurred to the lateral FHB and lateral sesamoid in only 2 and 3 specimens, respectively. Additionally, some erosion of the plantar base of the proximal phalanx was observed in one specimen. Conclusion: The plantar structures of the hallux MTP are a tightly constrained system, which are violated during plantar approach retrograde intramedullary medial column fixation. No structures were completely transected and high-grade damage (greater than 50%) was infrequent, occurring in only two FHL tendons. Low-grade damage (less than 50%) was frequently observed to involved the FHL, medial sesamoid, and plantar plate. Based on the current findings, an FHL splitting or preserving approach is advisable to avoid high-grade damage if plantar approach is desired. A dorsal arthrotomy approach avoiding plantar structures may also be considered

Reliability of the “Clinical Tibiofibular Line” Technique for Open Syndesmosis Reduction Assessment

Category: Ankle, Trauma Introduction/Purpose: When intraoperative CT is unavailable, open syndesmosis assessment is a universally available safe alternative that is more accurate than radiographic assessment. However, it has a documented malreduction rate of up to 16%. This may be improved by a validated technique for assessing the accuracy of the open syndesmosis reduction but none currently exists. The ‘tibiofibular line’ (TFL) was described as a tangential line between the flat anterolateral surface of the distal fibula and the anterolateral tubercle of the distal tibia as viewed on ankle axial CT images 10 millimeters (mm) above the plafond (Figure 1a). This finding was sensitive for syndesmosis malreduction. The purpose of this study was to assess the feasibility of adapting the CT-based TFL method into a reliable intraoperative open technique. Methods: This was an IRB-exempt study utilizing 10 cadaveric lower limbs. Three observers were instructed to clinically simulate the TFL by using two surgical rulers. The axial plane was marked 10 mm above the tibial plafond (Figure 1b and 1c). The first ruler was held tangent to the flat anterolateral surface of the fibula (Figure 1d). Then, it was advanced anteromedially until it either contacted or overhung the anterior tibial tubercle (Figure 1e). Then, a second ruler was used to measure the narrowest distance between the first ruler and anterior tibial tubercle (Figure 1f). Observers repeated and recorded clinical TFL measurements three times per measurement series. Four measurement series were conducted: one with syndesmosis intact followed by three series with sagittal plane fibular displacements of known magnitudes. Intraclass correlation was used to assess intraobserver and interobserver reliability. Accuracy of clinical TFL measurements was not assessed due to lack of CT. Results: The three observers generated a total of 1080 clinical TFL measurements. Mean intraobserver reliability was 0.88 (range, 0.72 to 0.98). For observers 1, 2, and 3, respectively, mean intraobserver reliability was 0.92 (range, 0.86 to 0.98), 0.92 (range, 0.78 to 0.98), and 0.80 (range, 0.72 to 0.97). Mean interobserver reliability was 0.75 (range, 0.68 to 0.93). Both intraobserver and interobserver reliability were highest for anatomic syndesmosis reduction (Intraobserver reliability mean 0.97, range, 0.96 to 0.98; Interobserver reliability 0.93) and lowest for the greatest magnitude of malreduction (Intraobserver reliability mean 0.81, range, 0.76 to 0.88; Interobserver reliability 0.77). Conclusion: Intraoperative computed tomography is the gold standard for syndesmosis reduction assessment but its availability is limited due to feasibility and cost constraints. The importance of the current study is the concept of translating the objectivity of a CT-based technique into the otherwise highly subjective open technique. The current findings indicate that this can be done with excellent to near perfect intraobserver and good to excellent interobserver reliability. Future work is merited to assess the accuracy of the clinical TFL measurements against a CT facilitated TFL measurement

Beaming in Charcot Arthropathy- Intramedullary Fixation for Complicated Reconstructions

Category: Midfoot/Forefoot Introduction/Purpose: In the modern treatment of Charcot neuroarthropathy, beam screw fixation is an attractive alternative to plate and screw fixation because it minimizes the required exposure for implantation and supports the longitudinal columns of the foot from the inside out as a rigid yet load-sharing construct. Oversized implants risk metatarsal fracture and undersized implants risk implant fracture or impaired healing from mechanical instability. Our review of the scientific literature identified a lack of evidence regarding the aspects of metatarsal intramedullary canal morphology relevant to beam screw fixation. The purpose of the present study was to qualitatively and quantitatively describe metatarsal diaphyseal morphology. Methods: Twenty fresh-frozen adult cadaveric below knee specimens were utilized to assess the size and shape of the diaphysis of metatarsals 1-4. There were 10 male and 10 female specimens with a mean age of 75.8 years. No limbs had outward signs of prior injury/surgery, radiographic signs of Charcot neuroarthropathy or previous fracture. Metatarsals 1-4 were excised, cleaned of all soft tissue and then axially transected at the point of most narrow external diameter. The diaphyseal canal shape was categorized as round, oval, triangular, or pear. The widest distance between two endosteal cortical surfaces was measured. Results: Triangular endosteal canals were only found in the 1st metatarsal whereas the remainder of metatarsals canals were largely round or oval. The mean diameter of the 1st metatarsal was 9.08 ± 1.26 mm. The mean diameter of the 2nd metatarsal was 4.72 ± 0.82 mm. The mean diameter of the 3rd metatarsal was 4.53 ± 0.88 mm. The mean diameter of the 4th metatarsal was 4.51 ± 1.10 mm. Conclusion: Intramedullary fixation by internal beaming of the columns of the foot can provide anatomical alignment with stabile fixation in cases of patients with Charcot arthropathy. Our study has given the smallest average diameter for metatarsals one through 4. This data is helpful when determining what size fixation to choose to achieve the maximum screw-endosteal purchase for column beaming in Charcot reconstructions

Development of a Predictive Model for the Outcome of Nonsurgical Treatment of Insertional Achilles Tendinosis

Category: Hindfoot Introduction/Purpose: Insertional Achilles tendinosis (IAT) is less responsive to nonsurgical treatment than midstubstance disease. The purpose of this study was to develop a predictive model for the treatment outcomes of patients with IAT. Objectives were to discriminate between predictive and non-predictive presenting parameters with respect to the outcome of nonsurgical treatment, to develop a predictive model using these parameters which assigns individual patients a likelihood of failing nonsurgical treatment based on their respective risk profiles, and to validate this model. Methods: Following IRB-approval, patients with Achilles tendinosis were identified using ICD-9 code 726.71. The authors reviewed medical records and included all 664 patients with IAT who underwent at least 3 months of nonsurgical treatment. Exclusion criteria included midstubstance or bilateral disease, skeletal immaturity, or previous hindfoot surgery. Parameters collected included presenting age, gender, body mass index, presence of diabetes mellitus or rheumatoid arthritis, tobacco use, workman’s compensation status, previous corticosteroid injection, ankle range of motion, visual analogue pain score, Foot and Ankle Ability Measure score, presenting SF-12 score, presence of Haglund’s exostosis, insertional enthesophyte or intrasubstance calcification. Univariate analysis was used to describe the study population. A multivariate logistic regression was developed and pruned using Akaike information criterion. The final model was used to predict an individual’s likelihood of undergoing surgery for IAT and the model was validated using bootstrapping analysis. Results: The study sample was 53% female, had a mean age of 53.7 years (SD 14.7 years), and 80% were overweight or obese. Duration of symptoms at presentation averaged 10.4 months (range, 0 to 348 months, SD 28 months). 1 in 12 patients failed nonsurgical treatment. Final predictors of outcome were presenting visual analog scale >4 (OR 1.13, 95% CI 1.01 -1.26, p=0.02), limited ankle range of motion (OR 0.33, 95% CI 0.19-0.58, p < 0.01), previous corticosteroid injection (OR 2.33, 95% CI 1.06-5.10, p=0.04), and Achilles insertion enthesophyte (OR 2.21, 95% CI 1.38-3.54, p < 0.01). The model assigned a risk of failure ranging from 5% for one predictor to 55% for 4 predictors. For this model, the area underneath the curve was 0.7. Conclusion: These data indicate that patients with IAT can be risk-stratified according to presenting data. A validated model for risk stratifying patients with IAT did not exist prior to this study. Such a model has potential utility in clinical care and when planning and interpreting the outcomes of clinical trials. Strengths of this study were its breadth of included parameters and its large sample size. Weaknesses were its retrospective nature and lack of a defined nonoperative treatment protocol. While encouraging, these findings require prospective validation prior to clinical or investigational use

Content Relevance of the Foot and Ankle Ability Measure in Patients with Achilles Tendon Diseases

Category: Sports Introduction/Purpose: The Foot and Ankle Ability Measure (FAAM) is a widely used evaluative, region-specific patient reported outcome measure. Its construct validity, test-retest reliability, and responsiveness are reasonably well supported in patients with a variety of lower extremity musculoskeletal conditions. However, since its development, the FAAM’s content relevance has never been subject to patient assessment. Therefore, this study was designed to assess the content relevance of the FAAM among patients with Achilles tendon diseases. Methods: IRB-approved, prospective, observational study of patients with Achilles tendon diseases. Subjects gave informed consent to complete a standard FAAM and a FAAM content relevance questionnaire. For each item of the relevance questionnaire, the standard FAAM’s visual analogue scale was replaced by a categorical scale asking subjects to rank the individual item as 1-Not Relevant, 2-Somewhat Relevant, or 3-Very Relevant to their lower extremity condition. The same was asked regarding both the entire ADL and Sports subscales, respectively. Descriptive statistics (mean, standard deviation) were calculated using pooled individual question scores and then 95% confidence intervals were constructed. Any individual item or subscale with a mean score above 2.0 was considered to have substantial content relevance. Floor and ceiling effects were deemed to have been present if 20% or more of patients gave all items of a subscale either the lowest or highest possible scores, respectively. Results: There were 59 respondents with mean age of 52.6 years (range, 28 to 79 years). Mean time from presentation to content relevance assessment was 19.6 weeks (range, 1 to 100 weeks). There were 39 (66%) surgical patients and 20 (34%) nonsurgical patients. Diagnoses included 28 (47%) rupture, 18 (31%) tendinosis, and 13 (22%) paratenonitis. 10 (17%) were pre- treatment and 49 (83%) post-treatment. For each individual item and subscale, the mean relevance was above 2.0 indicating substantial relevance. The 95% confidence interval crossed below this threshold for only one item, ‘Personal Care’ (mean 2.02, 95% CI 1.79 to 2.24). No floor effects were detected. Ceiling effects were apparent for only the Sports subscale (n=25,42.4%). Conclusion: These findings demonstrate that the FAAM has substantial item and subscale-level content relevance in patients with Achilles tendon diseases. Future work should aim to provide additional psychometric data specific to patients with Achilles tendon diseases in order to allow more precise use of the FAAM in this specific patient population

Anterior Ankle Incision Complications

Category: Ankle Introduction/Purpose: The anterior incision is commonly used for total ankle replacement (TAR), and anterior approach ankle arthrodesis. Historically, the anterior incision has demonstrated a high incidence of complications, specifically with early generation TAR. Modern TAR designs have provided instrumentation and techniques that better respect the vulnerability of the anterior soft tissues, potentially reducing the incidence of anterior incision related complications. To our knowledge, anterior wound healing rates have not been evaluated in the context of modern anterior approach ankle arthrodesis and arthroplasty. The purpose of this study was to evaluate and compare the incisional healing and complications of the anterior approach for ankle arthrodesis and arthroplasty. Methods: This was an IRB-approved retrospective review of wound healing and complications among 304 patients who underwent primary TAR or ankle arthrodesis via the anterior approach between August 1, 2011 and August 31, 2015. Of the 304 patients, 191 (62.8%) underwent TAR and 113 (37.2%) underwent arthrodesis. The surgical approach, intraoperative soft tissue handling, and postoperative protocol for the first 30 days was the same between groups. Demographics, clinical characteristics of the wound healing, and neurovascular status were analyzed using two-sample t-tests or Wilcoxon rank sum tests for continuous variables and chi-square or Fisher’s exact tests for categorical variables. To diminish the effect of selection bias, a subgroup analysis was performed comparing 91 TAR patients matched to an equal number of ankle arthrodesis patients based upon gender, age, diabetes, and smoking status. Results: The mean follow-up was 11.8 (range, 1.4 to 62.2) months. Overall, 19.7% of patients experienced delayed wound healing greater than 30 days, 15.8% required office-based wound care, 12.2% had a wound infection, 15.1% were prescribed antibiotics, 9.5% underwent wound debridement in the office, 4.6% had nerve injury, and 0.7% had a vascular injury. Implant revision or removal occurred in 10.5%, with a bias towards hardware removal in ankle arthrodesis. In the entire group of 304 patients, there was no difference between TAR and arthrodesis in risk of incisional wound challenges or complications nor neurovascular injury. In the subgroup matched for gender, age, diabetes status and smoking history there was no difference in outcomes. Conclusion: In this large cohort of 304 patients undergoing anterior approach to the ankle, postoperative complication rates were constant at all levels of analysis, with no difference seen between anterior ankle arthrodesis or ankle approach total ankle arthroplasty. This suggests that the primary determinates of complications were neither the demographic nor implant factors considered herein. The anterior ankle incision has a documented wound complication risk, regardless of the surgical procedure, and any modifiable risk factors remain elusive

Medial Structure Injury During Suture Button Insertion Utilizing “Center-Center” Technique for Syndesmotic Stabilization

Category: Ankle Introduction/Purpose: The “Center-Center” technique for syndesmosis fixation has been described as an improved and reliable technique for proper reduction of the syndesmosis during ankle fracture repair. Concurrently, the use of a flexible suture button is becoming an established means of syndesmotic stabilization. The purpose of this cadaveric study was to assess for medial structure injury during the placement of a suture button utilizing the “Center-Center” technique for ankle syndesmotic repair at 3 insertion intervals. Methods: Simulated open syndesmosis repair was performed on 10 cadaveric specimens. Three intervals were measured at 10 mm, 20 mm, and 30 mm proximal to the level of the distal tibial articular surface along the fibula. Proper longitudinal alignment of the “Center-Center” technique was completed under fluoroscopic guidance and was marked on the medial aspect of the tibia. The 3 intervals were drilled in the appropriate technique trajectory. The suture button was passed through each drill-hole interval. Using a digital caliper, the distance was measured from each suture button aperture with respect to the anterior tibial tendon, posterior tibial tendon, greater saphenous vein and nerve by single observer. Results: The average distance from the suture button to each anatomic structure was -2.61 ± 3.75 mm for the greater saphenous vein, -3.44 ± 6.82 mm for the saphenous nerve, 15.09 ± 4.02 mm for the anterior tibial tendon, and -21.70 ± 4.89 mm for the posterior tibial tendon. Direct impingement of the greater saphenous vein was seen in 11/30 (36.6%) interval measurements. Six of the 11 (54.5%) entrapment intervals occurred at the 10 mm drill hole. Conclusion: The results of the present study suggest the use of the “Center-Center” technique for syndesmotic repair with suture button application does involve risk of injury to the greater saphenous vein and saphenous nerve. These injuries could manifest as persistent lower extremity edema and paresthesias for injury to the saphenous vein and nerve respectively. The “Center-Center” technique with suture button fixation may warrant a minimal medial open dissection, prior to quadricortical drilling, for optimal placement to prevent neurovascular injury

Results of Augmented Half-Thickness Tibialis Anterior Tendon Segment Transposition, a Novel Technique for Tibialis Anterior Tendon Reconstruction

Category: Ankle Introduction/Purpose: Tibialis anterior tendon (TAT) rupture causes substantial morbidity. Nearly 200 surgical cases have been reported in the literature since 1905 wherein primary repair was not achieved approximately 40% of the time due to post- debridement tendon defect size. The present study describes the clinical outcomes of augmented, half-thickness TAT segment transposition, a novel reconstruction technique for managing post-debridement TAT defect. The purpose was to assess this technique as an alternative to tendon transfer and allograft tendon interposition. Methods: IRB-approved, retrospective electronic medical record review of patients with attritional distal TAT rupture. In all cases, the post-debridement tendon defect prohibited primary repair or reinsertion and was managed by distal transposition of a half-thickness TAT segment to span the defect. This graft was secured with a six core suture end-to-end anastomosis. Then, this repair was augmented with human acellular dermal matrix allograft (Graftjacket®, Wright Medical Technology, Memphis, TN). A total of five patients were treated with this technique. One patient died of unrelated causes remote from surgery and one was lost to follow up. Three patients with a minimum one year follow up were included. Outcomes were assessed via observed range of motion, clinical motor power assessment, ability to heel walk 15 feet, visual analog scale pain score, Foot and Ankle Ability Measure score, postoperative complications, and patient satisfaction at one year. Outcomes data were analyzed using descriptive statistics. Results: The mean age was 68 years (range, 59 to 73 years). Two patients were female. Mean interval between injury and surgery was 59.3 days (range, 15 to 146 days). All patients regained symmetrical range of motion, medical research council grade 5 motor power and the ability to heel walk. Mean pain scores improved from 4.6 (range, 2.5 to 8.5) preoperatively to 0.7 (range, 0 to 2) postoperatively. Mean FAAM scores increased from 30.6 (range, 23.8 to 43.8) preoperatively to 78.7 (range, 72.6 to 97.6) postoperatively. No postoperative complications occurred. At one year, one patient was satisfied and two were very satisfied with their outcome. Conclusion: Although constrained by a small sample size, the present findings appear to indicate that this technique produces short term clinical results comparable to those described for other techniques for TAT reconstruction. Future work should assess if these results are reproducible and long lasting. Additionally, the relative value of saving donor site morbidity or the cost of allograft tendon in comparison to the added cost of the Graftjacket should be determine