Jackson Staggers

Novel animal model for Achilles tendinopathy: Controlled experimental study of serial injections of collagenase in rabbits

Our goal was to develop a novel technique for inducing Achilles tendinopathy in animal models which more accurately represents the progressive histological and biomechanical characteristic of chronic Achilles tendinopathy in humans. In this animal research study, forty-five rabbits were randomly assigned to three groups and given bilateral Achilles injections. Low dose (LD group) (n = 18) underwent a novel technique with three low-dose (0.1mg) injections of collagenase that were separated by two weeks, the high dose group (HD) (n = 18) underwent traditional single high-dose (0.3mg) injections, and the third group were controls (n = 9). Six rabbits were sacrificed from each experimental group (LD and HD) at 10, 12 and 16 weeks. Control animals were sacrificed after 16 weeks. Histological and biomechanical properties were then compared in all three groups. At 10 weeks, Bonar score and tendon cross sectional area was highest in HD group, with impaired biomechanical properties compared to LD group. At 12 weeks, Bonar score was higher in LD group, with similar biomechanical findings when compared to HD group. After 16 weeks, Bonar score was significantly increased for both LD group (11,8±2,28) and HD group (5,6±2,51), when compared to controls (2±0,76). LD group showed more pronounced histological and biomechanical findings, including cross sectional area of the tendon, Young’s modulus, yield stress and ultimate tensile strength. In conclusion, Achilles tendinopathy in animal models that were induced by serial injections of low-dose collagenase showed more pronounced histological and biomechanical findings after 16 weeks than traditional techniques, mimicking better the progressive and chronic characteristic of the tendinopathy in humans.

Cadaveric study of the infrapatellar branch of the saphenous nerve: Can damage be prevented in total knee arthroplasty?

BackgroundnThe infrapatellar branch of the saphenous nerve (IPBSN) is a purely sensory nerve innervating the anteromedial aspect of the knee and anteroinferior knee joint capsule. Total knee arthroplasty (TKA) is commonly used to treat end-stage arthritis, but the IPBSN is often injured and results in numbness around the anteromedial knee. The aim of this cadaveric study was to describe the course and variability of the IPBSN and to assess whether it is possible to preserve during a standard midline surgical approach in TKA.nnnMethodsnTen fresh-frozen cadaver legs were dissected using a midline approach to the knee. Skin and subcutaneous flap were reflected to expose both the saphenous nerve and its branches. The branches of the IPBSN were identified, and their vertical distances above the tibial tuberosity (TB) were recorded: TB to inferior branch, to middle branch, and to superior branch.nnnResultsnThere were 10 left-sided specimens (6 female, 4 male) with a mean age of 79.9u202f±u202f9.8u202fyears. 8 (80%) specimens had 2 branches of IPBSN while 2 (20%) specimens had 3 branches. The average distance from TB to the inferior branch was 16.8u202f±u202f8.3u202fmm (3.0-28.0); middle branch, 24.0u202f±u202f1.4u202fmm (23.0-24.9); and superior, 45.9u202f±u202f7.7u202fmm (32.0-54.5).nnnConclusionnOur cadaveric study found no consistent way to preserve the IPBSN using a standard midline approach in TKA. It is important to provide proper patient education on this complication, and surgeons should be aware of approximate locations and variations of IPBSN while performing other knee procedures.

A systematic review and meta-analysis of complications in conversion arthroplasty methods for failed intertrochanteric fracture fixation

BackgroundnConversion arthroplasty for failed primary fixation of intertrochanteric fractures can be achieved using various methods, including cemented total hip arthroplasty, uncemented total hip arthroplasty, hybrid total hip arthroplasty, and hemiarthroplasty. Complication rates vary between each conversion method. The purpose of this paper is to examine the effect of conversion method on total conversion complication rates.nnnMethodsnWe performed a meta-analysis of five studies with sufficient data for analysis. We created a null hypothesis stating that the expected distribution of complications across conversion methods would reflect the distribution of conversion method used for failed primary fixation. Using a z test, we compared proportions of the expected distribution of complications to the observed distribution of complications.nnnResultsnA total of 138 cases of conversion arthroplasty with 49 complications were available for analysis. The mean age was 73 (range, 32-96) years. 19 males and 48 females were included, with one study not including patient gender. The mean time from primary fixation failure to conversion was 11 months, and the mean duration of conversion surgery was 132u202fmin. Expected and observed complication rate distributions were as follows: cemented total hip arthroplasty, 6.5% versus 4.1% (pu202f=u202f0.79); uncemented total hip arthroplasty, 77.5% versus 81.6% (pu202f=u202f0.69); hybrid total hip arthroplasty, 2.9% versus 2.0% (pu202f=u202f1); and hemiarthroplasty, 13% versus 12.2% (pu202f=u202f1).nnnConclusionsnOur findings suggest that the method of conversion arthroplasty following failed primary intertrochanteric femur fracture fixation does not influence complication rate.

Reconstruction for chronic Achilles tendinopathy: comparison of flexor hallucis longus (FHL) transfer versus V-Y advancement

BackgroundSeveral operative techniques exist for Achilles tendinopathy. The purpose of our study was to compare the clinical and functional outcomes of flexor hallucis longus (FHL) transfer and V-Y advancement for the treatment of chronic insertional Achilles tendinopathy.MethodsRetrospective chart review from 2010 to 2016 of patients that underwent FHL transfer or V-Y advancement for chronic insertional Achilles tendinopathy. Outcome measures were compared for these two procedures.ResultsIn total, 46 patients (49 ankles) with a mean age of 55.0 (range 33–73)xa0years. Mean follow-up time 44.7u2009+/−u200925.5xa0months. FHL group had 21 patients (21 ankles) with 89% satisfaction, 14% complication rate, final VAS of 0.4, final VISA-A of 89.1, subjective strength improvement following surgery of 78%, and 94% would recommend the procedure. V-Y group had 25 patients (28 ankles) with 74% subjective satisfaction, 21% complication rate, final VAS of 1.4, final VISA-A of 78.4, subjective strength improvement following surgery of 67%, and 84% would recommend the procedure. There was no significant difference in any of the results rates between the two groups (pu2009>u2009.05).ConclusionV-Y advancement is comparable to FHL transfer for the operative management of insertional Achilles tendinopathy. Though our results trend towards less satisfactory results following V-Y advancement, we found high satisfaction rates with similar functional outcomes and complication rates in both operative groups. We suggest considering V-Y advancement as a viable option for the primary treatment of chronic insertional Achilles tendinopathy in patients who may not be an ideal candidate for FHL transfer.

Clinical Outcomes of Cervical Facet Fractures Treated Nonoperatively With Hard Collar or Halo Immobilization

Study Design: Retrospective review. Objectives: To evaluate the rate of nonoperative treatment failure for cervical facet fractures while secondarily validating computed tomography–based criteria proposed by Spector et al for identifying risk of failure of nonoperative management. Methods: Single-level or multilevel unilateral cervical facet fractures from 2007 to 2014 were included. Exclusion criteria included spondylolisthesis, dislocated or perched facets, bilateral facet fractures at the same level, floating lateral mass, thoracic or lumbar spine injuries, or spinal cord injury. Patients were placed into 3 groups for evaluation: immediate operative management, successful nonoperative management, and failed nonoperative treatment requiring surgical intervention. Results: Eighty-eight patients (106 facets) were included. Twenty-one patients underwent operative treatment with anterior cervical discectomy and fusion or posterior spinal instrumentation and fusion without any failures. Sixty-seven of these patients were treated nonoperatively with either a hard collar (n = 62) or halo vest (n = 5). Eleven patients failed nonoperative treatment (16.4%), all with an absolute fracture height of at least 1u2009cm and 40% involvement of the absolute height of the lateral mass. Of the 56 patients successfully treated through nonoperative measures, 8 (14.3%) had fracture measurements exceeding both operative parameters. Conclusion: We conclude that it is safe and appropriate for patients with unilateral cervical facet fractures to receive a trial period of nonoperative management. However, patients who weigh over 100u2009kg, have comminuted fractures, or have radiographic measurements outside of the proposed computed tomography criteria for nonoperative treatment should be educated on the risks of treatment failure.

Percutaneous Posterior to Anterior Screw Fixation of the Talar Neck: Soft Tissue Structures at Risk

Category: Trauma Introduction/Purpose: Fractures of the talar neck and body can be fixed with percutaneously placed screws directed from anterior to posterior or posterior to anterior. The latter has been found to be biomechanically and anatomically superior. Percutaneous pin and screw placement poses anatomic risks for posterolateral and posteromedial neurovascular and tendinous structures. The objective of this study was to enumerate the number of trials for proper placement of two parallel screws and to determine the injury rate to neurovascular and tendinous structures. Methods: Eleven fresh frozen cadaver limbs were used. 2.0 mm guide wires from the Stryker (Selzach, Switzerland) 5.0-mm headless cannulated set were percutaneously placed (under fluoroscopic guidance) into the distal posterolateral aspect of the ankle. All surgical procedures were performed by a fellowship-trained foot and ankle surgeon. Malpositioned pins were left intact to allow later assessment of soft tissue injury. The number of guide wires needed to achieve an acceptable positioning of the implant was noted. Acceptable positioning was defined as in line with the talar neck axis in both AP and lateral fluoroscopic views. After a layered dissection from the skin to the tibia, we evaluated neurovascular and tendinous injuries, and measured the shortest distance between the closest guide pin and the soft tissue structures, using a precision digital caliper. Results: The mean number of guide wires needed to achieve acceptable positioning for 2 parallel screws was 2.91 ± 0.70 (range, 2 - 5). The mean distances between the closest guide pin and the soft tissue structures of interest were: Achilles tendon, 0.53 ± 0.94 mm; flexor hallucis longus tendon, 6.62 ± 3.24 mm; peroneal tendons, 7.51 ± 2.92 mm; and posteromedial neurovascular bundle, 11.73 ± 3.48 mm. The sural bundle was injured in all the specimens, with 8/11 (72.7%) in direct contact with the guide pin and 3/11 (17.3%) having been transected. The peroneal tendons were transected in 1/11 (9%) of the specimens. The Achilles tendon was in contact with the guide pin in 6/11 (54.5%) specimens and transected in 2/11 (18.2%) specimens. Conclusion: The placement of posterior to anterior percutaneous screws for talar neck fixation is technically demanding and multiple guide pins are needed. Our cadaveric study showed that important tendinous and neurovascular structures are in close proximity with the guide pins and that the sural bundle was injured in 100% of the cases. We advise performing a formal small posterolateral approach for proper visualization and retraction of structures at risk. Regardless, adequate patient education about the high risk of injury from this procedure is crucial.

Percutaneous Tendon Achilles Lengthening: What Are We Really Doing?

Category: Hindfoot Introduction/Purpose: Percutaneous Achilles tendon lengthening (TAL) is a common procedure used to address equinus contracture of the foot. A triple hemisection technique has become popular due to its ease and efficiency. Several studies evaluate the surgical outcomes of this procedure, but currently, descriptive anatomical studies are lacking. The objective of the study was to evaluate the accuracy of performing Achilles tendon percutaneous hemisections, the amount of tendon excursion in the tensile gaps of the cuts after forced dorsiflexion and the improvement in the range of motion for dorsiflexion of the ankle joint. Methods: Ten fresh-frozen above-knee cadaveric specimens were used. A percutaneous triple hemisection of theAchilles tendon (proximal, intermediate, and distal) was performed. Maximum ankle dorsiflexion was evaluated pre- and postprocedure with a digital goniometer. After proper dissection, the relative width of the cuts was noted. Followingforced ankle dorsiflexion, displacement in the tensile gaps was measured in all 3 cuts with a precision digital caliper. Results: The overall relative width of the percutaneous cut was 51.3% ± 16.3% of the Achilles tendon diameter, 44.3%± 13.6% for the proximal cut, 50.3% ± 15.6% for the intermediate cut, and 59.3% ± 18.4% for the distal cut. Tendonexcursion averaged 13.0 ± 3.8 mm for the proximal cuts, 12.5 ± 4.7 mm for the intermediate cuts, and 8.2 ± 3.7 mm forthe distal cuts. One cadaver had a complete rupture of the Achilles tendon and was excluded from the excursion dataanalysis. The mean range of motion for ankle dorsiflexion was 8.1 ± 3.9 degrees preprocedure and 27.6 ± 5.3 degreespostprocedure. The dorsiflexion angle significantly increased (P < .0001) at an average of 19.5 ± 5.0 degrees following TAL. Conclusion: Our cadaveric study demonstrated that the percutaneous triple hemisection of the Achilles was an accuratetechnique that provided successful lengthening of the tendon and increased ankle dorsiflexion. Complete ruptures arepossible complications. Our cadaveric study showed that in a clinical situation, triple hemisections of the Achilles tendon can be performed reliably, with significant improvement of the ankle dorsiflexion, mainly through increased tendon excursion at the proximal and intermediate cuts, and with low risk of complete ruptures.

Intraoperative Syndesmotic Instability Test: A Novel Alternative Technique

Category: Ankle, Trauma Introduction/Purpose: Precise diagnosis of distal tibiofibular syndesmotic injury is challenging and a gold standard diagnostic test has still not been established. Tibiofibular clear space identified on radiographic imaging is considered the most reliable indicator of the injury. The Cotton test is the most widely used intraoperative technique to evaluate the syndesmotic integrity although it has its limitations. We advocate for a novel intra operative test using a 3.5 mm cortical tap. Methods: Tibiofibular clear space was assessed in nine cadaveric specimens using three sequential fluoroscopic images. The first image was taken prior to the application of the tap test representing the intact and non-stressed state. Then, a 2.5 mm hole was drilled distally on the lateral fibula, and a 3.5 mm cortical tap was then threaded in the hole. The tap test involved gradually advancing the blunt tip against the lateral tibia, providing a tibiofibular separation force (intact, stressed). This same stress was then applied after all syndesmotic ligaments were released (injured, stressed). Measurements were compared by one-way ANOVA and paired Student’s t-test. Intra and inter-observer agreements were evaluated by intraclass correlation coefficient (ICC). P-values <.05 were considered significant. Results: We found excellent intra-observer (0.97) and inter-observer (0.98) agreement following the imaging assessment. Significant differences were found in the paired comparison between the groups (p<.05). When using an absolute value for TFCS >6 mm as diagnostic for syndesmotic instability, the tap test demonstrated a 96.3% sensitivity and specificity, a 96.3% PPV and NPV and a 96.3% accuracy in diagnosing syndesmotic instability. Conclusion: Our cadaveric study showed that this novel syndesmotic instability test using a 3.5 mm blunt cortical tap is a simple, accurate and reliable technique able to demonstrate significant differences in the tibiofibular clear space when injury was present. It could represent a more controlled and stable low-cost alternative to the most used Cotton test.

Ankle Fusion Percutaneous Home Run Screw Fixation: technical aspects and soft tissue structures at risk

Category: Ankle Arthritis Introduction/Purpose: During internal fixation of ankle fusions, besides the standard crossed screw fixation pattern, the use of a percutaneously placed augmenting screw, directed from the posterolateral tibial metaphysis proximally across the ankle into the talar neck (“ankle fusion home run screw”), is a widely used technique. The placement of this screw is technically demanding and multiple attempts under fluoroscopy guidance are frequently needed to achieve a perfect positioning of the implant. Injuries to local neurovascular and tendinous structures might happen. The objective of this cadaver study was to identify the number of attempts necessary for a perfect positioning of the ankle fusion home run screw and the neurovascular and tendinous structures at risk. Methods: Eleven fresh frozen cadaver limbs were used. Guide wires (3.2 mm) from the Stryker (Selzach, Switzerland) 7.0-mm headless cannulated set were percutaneously placed into the distal posterolateral aspect of the leg, under fluoroscopic guidance, with the ankle held in neutral position. Mal positioned pins were not removed and served as guidance for the following pins. The number of guide wires needed to achieve an acceptable positioning of the implant was noted. After a layered dissection from the skin to the tibia, we evaluated neurovascular and tendinous injuries, and measured the shortest distance between the closest guide pin and the soft tissue structures, using a precision digital caliper. Results: The mean number of guide wires needed to achieve and acceptable positioning of the implant was 2.09 (SD 0.83, range 1- 4). The mean distances between the closest guide pin and the soft tissue structures of interest were: Achilles tendon 6.90 mm (SD 3.74 mm); peroneal tendons 9.65 mm (SD 3.99 mm); sural neurovascular bundle 0.97 mm (SD 1.93 mm); posteromedial neurovascular bundle 14.26 mm (SD 4.56 mm). Sural bundle was in contact with the guide pin in 5/11 specimens (45.5%) and transected in 3/11 specimens (27.3%). Conclusion: The placement of percutaneous ankle fusion home run screws is technically demanding and multiple guide pins are needed. Our cadaveric study showed that important tendinous and neurovascular structures are in close proximity with the guide pins and that the sural bundle is injured in approximately 73% of the cases. Caution should be taken during percutaneous placing of screws and an appropriate approach and surgical dissection to bone is advised.

Anatomic Evaluation of Percutaneous Achilles Tendon Lengthening

Background: The objective of the study was to evaluate the accuracy of percutaneous Achilles tendon lengthening (TAL) using a triple hemisection technique and the improvement in ankle dorsiflexion. Methods: Ten fresh-frozen above-knee cadaveric specimens were used. A percutaneous triple hemisection of the Achilles tendon (proximal, intermediate, and distal) was performed. Maximum ankle dorsiflexion was evaluated pre- and postprocedure with a digital goniometer. After proper dissection, the relative width of the cuts was noted. Following forced ankle dorsiflexion, displacement in the tensile gaps was measured in all 3 cuts with a precision digital caliper. Results: The overall relative width of the percutaneous cut was 51.3% ± 16.3% of the Achilles tendon diameter, 44.3% ± 13.6% for the proximal cut, 50.3% ± 15.6% for the intermediate cut, and 59.3% ± 18.4% for the distal cut. Tendon excursion averaged 13.0 ± 3.8 mm for the proximal cuts, 12.5 ± 4.7 mm for the intermediate cuts, and 8.2 ± 3.7 mm for the distal cuts. One cadaver had a complete rupture of the Achilles tendon and was excluded from the excursion data analysis. The mean range of motion for ankle dorsiflexion was 8.1 ± 3.9 degrees preprocedure and 27.6 ± 5.3 degrees postprocedure. The dorsiflexion angle significantly increased (P < .0001) at an average of 19.5 ± 5.0 degrees following TAL. Conclusion: Our cadaveric study demonstrated that the percutaneous triple hemisection of the Achilles was an accurate technique that provided successful lengthening of the tendon and increased ankle dorsiflexion. Complete ruptures are possible complications. Clinical Relevance: Our cadaveric study showed that in a clinical situation, triple hemisections of the Achilles tendon can be performed reliably, with significant improvement of the ankle dorsiflexion, mainly through increased tendon excursion at the proximal and intermediate cuts, and with low risk of complete ruptures.