Parallel versus Angulated Screw Configuration in Subtalar Arthrodesis for Posttraumatic Arthritis.

Background: To compare radiographic union and clinical outcomes between parallel and angulated screw configurations (SCs) for patients undergoing subtalar arthrodesis due to posttraumatic subtalar arthritis (PSA) after displaced intra-articular calcaneal fractures. Methods: This study retrospectively reviewed 140 consecutive PSA cases from March 2011 to November 2021 (parallel SC: group 1, n = 80; angulated SC: group 2, n = 60). Radiographic union, Foot and Ankle Outcome Score (FAOS), and visual analog scale (VAS) scores were among the outcome assessments. Six months after surgery, nonunion was confirmed based on plain radiographs, clinical evaluation, and computed tomography. Results: Groups 1 and 2 included 14 (17.5%) and 3 (5.0%) nonunion cases, respectively (p = 0.035). There was no significant difference in preoperative FAOS and VAS scores between the groups. However, group 2 had significantly better clinical outcomes in 2 of the 5 FAOS domains (sports and quality of life), as well as VAS scores at 3 and 6 months postoperatively and at the final follow-up (p < 0.05). Conclusions: Using the angulated SC for PSA had a lower nonunion rate and superior clinical outcomes than the parallel SC. Obtaining better radiological and clinical outcomes when using the angulated SC, rather than the parallel SC, would be advantageous.

Arthroscopic debridement and microfracture for bilateral osteochondral lesions on the lateral process of the talus involving the subtalar joint: A case report.

RATIONALE: Osteochondral lesions on the lateral process of the talus involving the subtalar joint are rare; the optimal surgical treatment remains to be clarified as there are few reports. Additionally, bilateral cases are extremely rare. Therefore, the clinical outcomes of the surgical treatment for bilateral osteochondral lesions on the lateral process of the talus involving the subtalar joint have not been fully elucidated. PATIENT CONCERNS: A 16-year-old boy who played soccer presented to our hospital with bilateral hindfoot pain. The symptoms persisted even after 3 months of conservative treatment. The patient and family requested surgical treatment to relieve the symptoms. DIAGNOSES: The patient was diagnosed with bilateral osteochondral lesions on the lateral process of the talus, involving the subtalar joint based on computed tomography and magnetic resonance imaging findings. INTERVENTIONS: Arthroscopic debridement and microfracture were performed bilaterally. OUTCOMES: Postoperative computed tomography and magnetic resonance imaging of both feet revealed remodeling of the subchondral bone. The patient returned to play at the pre-injury level with no pain. LESSONS: This report describes a case of bilateral osteochondral lesions on the lateral process of the talus, involving the subtalar joint. Arthroscopic debridement and microfracture were effective in relieving symptoms and the subchondral bone remodeling. To the best of our knowledge, this is the first report of arthroscopic treatment of osteochondral lesions of the lateral process of the talus involving the subtalar joint.

Simultaneous subtalar arthroeresis, midfoot soft tissue release, and talo-navicular arthrodesis in children with planovalgus neurologic foot.

PURPOSE: Planovalgus foot deformity (PVFD) is common in children with neuromuscular conditions and severe deformity may require surgical correction. This study aims to assess clinical and radiological outcomes of PVFD secondary to neuromuscular disease managed by subtalar arthroeresis (SuAE), midfoot soft tissue release and talo-navicular arthrodesis (TNA). METHODS: A retrospective analysis of children with neuromuscular disease and nonreducible PVFD who underwent SuAE, midfoot soft tissue release, and TNA and with a minimum follow-up of 5 years was performed. A total of 60 patients with neuromuscular disease (108 feet) including cerebral palsy were reviewed. Mean age at surgery was 12.7 ± 4.6 years (6-17). Mean follow-up was 7 ± 2.9 years (5-10). Clinical outcomes and radiologic correction at final follow-up were compared with preoperative values. Statistical analysis was performed and significance was set at P < 0.01. RESULTS: Statistically significant radiological improvements between pre- and postoperative values were found for all angle values. At final follow-up, there was a significant improvement in VAS score (4.8 vs. 2; P < 0.01). There was also a positive trend in the improvement of walking ability. No cases of pseudoarthrosis were reported at final follow-up. Screw removal was required in 5 out of 108 feet (4.6%) and 2 feet (3.3%) had delayed medial wound healing. CONCLUSIONS: SuAE combined with TNA and midfoot soft tissue is a safe and feasible procedure that can provide good clinical and radiologic results in patients with neuromuscular disease and nonreducible PVFD; the procedure can improve foot stability, and has a limited number of complications. LEVEL OF EVIDENCE: IV.

Hindfoot joint kinematics analysis after the resection of talocalcaneal coalition.

BACKGROUND: The subtalar joint movement between the talus and calcaneus is restricted in patients with talocalcaneal coalition (TCC). When the motion of the subtalar joint is restricted, shock absorption in the foot decreases, leading to pain during walking. Resection methods to maintain subtalar motion by removing abnormal unions have been proposed. The purpose of this study was to analyze the joint kinematics of patients who underwent TCC resection and to quantitatively evaluate the results of the surgery based on the measured kinematics. METHODS: Joint kinematics of five patients with TCC were obtained using a biplane fluoroscopic imaging system and an intensity-based two-/three-dimensional registration method. The joint kinematics of the tibiotalar and subtalar joints and the tibiocalcaneal motion during the stance phase of walking were obtained. From the kinematics of the hindfoot joints, the inversion/eversion range of motion (ROM) of the patients before and after resection was statistically analyzed using the Wilcoxon signed-rank test to test whether TCC resection improved the ROM. RESULTS: During the loading response period, the eversion ROM of the subtalar joint and tibiocalcaneal motion significantly increased postoperatively. In addition, a significant postoperative increase was observed in the subtalar and tibiocalcaneal inversion ROM during the pre-swing period. SIGNIFICANCE: TCC resection surgery increased the ROM of the subtalar joint, which in turn contributed to the increase in tibiocalcaneal ROM. Increased subtalar and tibiocalcaneal ROM could result in increased shock attenuation and may be a contributing factor to pain relief during walking.

Sustentaculum fracture fixation with lateral plate or medial screw fixation are equivalent.

BACKGROUND: Fixation of sustentaculum tali fractures is important to maintain the biomechanical function of the subtalar joint. A common method of fixation is securing the sustentacular fragment by way of a laterally based locking plate (LP). A medial approach with a single screw (MS) has been proposed as an alternative method of fixation. METHODS: Five pairs of formalin-preserved cadaveric ankles with the subtalar joint and interosseous ligaments intact ("osseous cadavers") and four pairs of fresh-frozen cadaveric ankles with soft-tissue preserved dissected from mid-tibia down ("soft tissue cadavers") were used in the study. The left ankle was randomly assigned to one of the two fixation methods (LP or MS), while the right ankle was the opposite. These same steps for fixation were repeated for six synthetic ankle models. All models were loaded with a body mass of 80 kg. Statistical differences between LP and MS stiffness were determined using a paired t-test in cadavers and un-paired t-tests in synthetic ankles. RESULTS: For osseous cadaveric ankles, LP demonstrated a mean stiffness of 232.95(SD: 59.96) N/mm, while MS was 239.72(SD:131.09) N/mm (p = 0.9293). For soft tissue cadaveric ankles, LP mean stiffness was 133.58(SD:37.84) N/mm, while MS was 134.88(SD:20.75) N/mm (p = 0.9578). For synthetic ankles, LP mean stiffness was 220.40(SD:81.93) N/mm, while MS was 261.50(SD:100.21) N/mm (p = 0.6116). CONCLUSIONS: Across all three models, there was no significant difference between LP and MS methods. Retrospective observational studies are recommended to assess patient outcomes from each of the methods.

[Evaluation of arthroscopic anterior talofibular ligament and calcaneofibular ligament repair separately for chronic lateral ankle instability in conjunction with subtalar instability].

Objective: To investigate the clinical efficacy of simultaneous arthroscopic repair of anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) for treating chronic lateral ankle instability (CLAI) in conjunction with subtalar instability (STI). Methods: This is a retrospective case series study. The clinical data of 15 patients with ankle arthroscopic in the Department of Hand and Foot Surgery, the Second Affiliated Hospital of Soochow University from January 2019 to December 2022 were analyzed retrospectively. There were 11 male cases and 4 female cases, aged (28.6±1.5) years (range: 19 to 39 years). All the patients were evaluated by manual inversion stress X-ray and MRI before operation. Arthroscopically observing and then repairing the ATFL and CFL separately after further diagnostic confirmation. One year after operation, MRI was performed, and pain visual analogue score(VAS), American Orthopedic Foot and Ankle Society ankle hindfoot scale (AOFAS-AH) and Karlsson ankle functional scale(KAFS) were evaluated. Data were compared using paired sample t test. Results: The follow-up period was (23.6±2.3) months (range: 12 to 30 months). At last follow-up,the VAS decreased from 6.1±1.4 preoperatively to 1.4±1.2(t=9.482, P<0.01).The AOFAS-AH improved from 50.5±11.7 preoperatively to 94.2±6.1(t=-13.132, P<0.01), and the KAFS improved from preoperatively 44.3±10.8 to 90.8±6.4 (t=-12.510, P<0.01). There was no complication such as recurred instability or joint stiffness. Conclusions: Arthroscopically repairing the ATFL and CFL separately can effectively restore the stability of the ankle and subtalar joint with small trauma. Patients can recover quickly after surgery. It provides a new idea for the clinical treatment of CLAI combined with STI.

Outcomes following tibiotalocalcaneal arthrodesis using a solid posterior offset intramedullary nail in 44 patients with a minimum 30-month follow-up.

BACKGROUND: Tibiotalocalcaneal arthrodesis is frequently performed by foot and ankle surgeons in the management of complex ankle and hindfoot pathology. In this study, the authors describe the clinical and radiological outcomes of tibiotalocalcaneal arthrodesis using a solid posterior offset hindfoot arthrodesis nail. METHODS: Forty-four consecutive patients underwent tibiotalocalcaneal arthrodesis by a single surgeon operating in two centers. Clinical and radiological outcomes were assessed preoperatively and at 6-month, 12-month and final follow-up (mean 47 months). Clinical outcomes were assessed with VAS, AOFAS and MOXFQ scores. Serial radiographs were used to assess union at each follow-up visit. RESULTS: Forty-four patients attended 12-month and final follow-up (mean 47 months). A total of 44 (100%) ankle joints and 44 (100%) subtalar joints were completely united at 12-month follow-up. The VAS score improved significantly from a mean of 6.5 preoperatively to a mean of 0.98 at final follow-up (P = <0.0001). AOFAS score improved significantly from a mean of 36.4 preoperatively to a mean of 73 at final follow-up (P = <0.0001). MOXFQ score improved significantly from a mean of 44.5 preoperatively to a mean of 12.7 at final follow-up (P = <0.0001). The mean change in frontal plane alignment was 5.7 degrees (P = 0.005). A total of 6 patients (13.6%) had an adverse event during the course of the study. CONCLUSIONS: Tibiotalocalcaneal arthrodesis with a solid posterior offset hindfoot arthrodesis nail is a safe and effective surgical option for patients with severe ankle and hindfoot pathology. It has a high union rate, low complication rate and significantly improves clinical outcomes.

Enhancing Post-Surgical Rehabilitation Outcomes in Patients with Chronic Ankle Instability: Impact of Subtalar Joint Axis Balance Exercises Following Arthroscopic Modified Broström Operation.

Background and Objectives: This study aimed to evaluate the effects of subtalar joint axis-based balance exercises on the anterior talofibular ligament (ATFL) thickness, ankle strength, and ankle stability after an arthroscopic modified Broström operation (AMBO) for chronic ankle instability (CAI). Materials and Methods: The study included 47 patients diagnosed with CAI who underwent AMBO and were randomly divided into three groups: control (n = 11), general balance exercise (n = 17), and subtalar joint axis balance exercise (n = 19), regardless of the affected area. Participants in the exercise rehabilitation group performed exercises for 60 min twice a week for six weeks, starting six weeks after AMBO. ATFL thickness, ankle strength, and ankle dynamic stability were measured using musculoskeletal ultrasonography, Biodex, and Y-balance test, respectively, before and after treatment. Results: Compared with the remaining groups, the subtalar joint axis balance exercise group had reduced ATFL thickness (p = 0.000), improved ankle strength for eversion (p = 0.000) and inversion (p = 0.000), and enhanced ankle stability (p = 0.000). Conclusions: The study results suggest that subtalar joint axis-based balance exercises may contribute to the early recovery of the ankle joint after AMBO.

Complications in Total Ankle Replacement.

The debate between ankle arthrodesis and total ankle replacement for patients with end-stage arthritis of the ankle joint is an ongoing topic in orthopedic surgery. Ankle arthrodesis, or fusion, has been the traditional treatment for ankle arthritis. It involves fusing the bones of the ankle joint together, eliminating the joint and creating a solid bony union. Arthrodesis is effective in reducing pain in the ankle, but it results in a loss of ankle motion. This can increase the load on adjacent joints, such as the subtalar joint, which may lead to accelerated degeneration and arthritis in those joints over time.

Biomechanical Effects of Subtalar Joint Fusion and Medial Ligament Reconstruction in Simulated Progressive Collapsing Foot Deformity.

BACKGROUND: The purpose of this study is to investigate the biomechanical effect of medial displacement calcaneal osteotomy (MDCO), subtalar joint fusion (SF), and medial ligament reconstruction (MLR: deltoid-spring ligament) in a severe flatfoot model. We hypothesized that (1) combination of MDCO and SF improves the tibiotalar and foot alignment in severe progressive collapsing foot deformity (PCFD) cadaver model. (2) However, if a residual valgus heel alignment remains after MCDO and SF, it can lead to increased medial ligament strain, foot malalignment, and tibiotalar valgus tilt, which will be mitigated by the addition of MLR. METHODS: Ten fresh-frozen cadaveric foot specimens were used to create a severe flatfoot model. The foot alignment changes, including the talo-first metatarsal angle in the axial and sagittal planes, subtalar angle, and tibiotalar angle in the coronal plane, were measured. The angles were measured at the initial condition, after creating the severe flatfoot model, and after each successive reconstructive procedure in the following order: (1) MDCO, (2) SF, and (3) MLR. RESULTS: Tibiotalar valgus tilt was decreased with the MDCO procedure: 4.4 vs 1.0 degrees (P = .04). Adding in situ SF to the MDCO led to increased tibiotalar tilt to 2.5 degrees was different from the initial condition (P = .01). Although the tibiotalar valgus tilt was significantly decreased after adding the MLR to the MDCO/SF procedure compared with the severe flatfoot model (0.8 vs 4.4 degrees, P = .03), no significant difference in the tibiotalar valgus tilt was observed between MDCO/SF and MDCO/SF with MLR. CONCLUSION: Our results demonstrated that MDCO significantly improved forefoot abduction and medial arch alignment, with no significant additional improvement observed with addition of SF. Following SF, a residual valgus heel alignment can contribute to subsequent tibiotalar valgus tilt. The addition of MLR did not show significantly decreased tibiotalar valgus tilt following SF. CLINICAL RELEVANCE: Residual valgus heel alignment after subtalar joint fusion in the surgical treatment of PCFD can lead to increased medial ligament strain. Although MLR might be considered for providing medial stability, it may not necessarily prevent the development of tibiotalar valgus tilt.

Reaming for Tibiotalocalcaneal Nailing Removes Only 10% of the Ankle and Subtalar Joints.

OBJECTIVES: Tibiotalocalcaneal (TTC) nailing in the setting of acute ankle trauma has become increasingly popular. No consensus exists as to whether formal joint preparation is necessary, although there is some concern that residual motion at unprepared joints may lead to implant loosening and/or breakage. The objective of this study was to quantify the proportion of tibiotalar and subtalar articular surface destruction that occurs during reaming for TTC nail fixation. METHODS: Twelve cadaver lower extremities were procured. The specimens were pinned into neutral ankle and hindfoot alignment. A guidewire was inserted under fluoroscopy, followed by a 12-mm opening reamer. The specimens were then dissected, exposing the tibial plafond, talar dome, posterior facet of the talus, and posterior facet of the calcaneus. Images of each joint were obtained, and ImageJ software was used to calculate the total joint surface area and the area of articular destruction. RESULTS: The mean proportion of articular cartilage destruction was 9.3%, 10.3%, 8.9%, and 10.3% for the tibial plafond, talar dome, posterior facets of the talus, and posterior facets of the calcaneus, respectively. No joint destruction was observed in the middle facets of the subtalar joint. CONCLUSIONS: Reaming for TTC nail placement violates approximately 10% of each articular surface of the tibiotalar and subtalar joints. Retention of 90% of the articular surface may allow for residual motion at the joints and therefore potentially substantial stress on the implant. Formal joint preparation for the purposes of achieving fusion during TTC nail placement may be beneficial to prevent implant loosening or breakage.

Defining the Structures at Risk and an Anatomical Safe Zone for Percutaneous Antegrade Subtalar Joint Fixation With a Single Screw: A Cadaveric Study.

Percutaneous antegrade (anterior to posterior) fixation for subtalar joint (STJ) arthrodesis offers various intraoperative and biomechanical advantages. Currently, the entry point for percutaneous antegrade STJ screw fixation is not clearly described and variable. To our knowledge, there are no publications that evaluate anatomic structures at risk or define an anatomically safe entry point for this fixation. The aim of this investigation was to define an anatomically safe and reproducible entry point for percutaneous antegrade STJ arthrodesis fixation, while also describing anatomic structures at risk when undertaking this method of fixation. We hypothesized that percutaneous single screw antegrade STJ fixation would encroach upon named anatomic structures in more than one cadaveric specimen. Ten cadaver limbs were used in this investigation. A percutaneous guidewire was inserted 5 mm lateral to the tibialis anterior tendon. The midpoint of the talar neck served as the sagittal plane starting point, as seen on the lateral fluoroscopic view. A cannulated 6.5-mm headed screw was inserted antegrade through the STJ into the calcaneus. Each specimen was dissected to assess the distance from the screw to nearby anatomic structures and distance from the tibialis anterior tendon to named structures. Our hypothesis was found to be incorrect, as 0/10 screws invaded neurovascular or tendinous structures. The dorsalis pedis artery and deep peroneal nerve were on average 12.1 ± 2.79 mm and 12.2 ± 2.82 mm lateral to the screw, respectively. These findings are clinically relevant and ultimately allow us to define an anatomic safe starting point for percutaneous antegrade STJ single screw fixation.

Osteochondral Lesions of the Subtalar Joint: Clinical Outcomes in 11 Patients.

OBJECTIVE: The purpose of this retrospective case series was to evaluate clinical outcomes following both conservative treatment and arthroscopic bone marrow stimulation (BMS) for the management of symptomatic subtalar osteochondral lesions (OCLs). DESIGN: All symptomatic subtalar OCLs with a minimum of 12 months follow-up having undergone either a conservative management or arthroscopic procedure were included. Patient-reported outcomes were collected via questionnaires consisting of the Foot and Ankle Outcome Score (FAOS), Numeric Rating Scale (NRS) of pain in rest, during walking, during stair climbing, and during running. In addition, return to sports data, return to work data, reoperations, and complications were collected and assessed. In total, 11 patients across 2 academic institutions were included (3 males, 8 females). The median age was 43 years (interquartile range [IQR]: 32-53). RESULTS: All patients underwent conservative treatment first; in addition, 9 patients underwent subtalar arthroscopic debridement with or without BMS. The median follow-up time was 15 months (IQR: 14-100). In the surgically treated group, the median NRS scores were 2 (IQR: 1-3) during rest, 3 (IQR: 2-4) during walking, 4 (IQR: 4-5) during stair climbing, 5 (IQR: 4-5) during running and the median FAOS score at final follow-up was 74 (IQR: 65-83). In the conservatively treated patients, the median NRS scores were all 0 (IQR: 0-0) and the median FAOS scores were 90 (IQR: 85-94). In the group of surgical treated patients, 4 were able to return to the same level of sports, 2 returned to a lower level of sports. Both conservatively treated patients returned to the sport and the same level of prior participation. All patients except one in the surgical group returned to work. CONCLUSIONS: This retrospective case series demonstrated that a high number of patients converted to surgery after initial conservative treatment. In addition, debridement and BMS show good clinical outcomes for the management of symptomatic subtalar OCLs at short-term follow-up. No complications nor secondary surgical procedures were noted in the surgically treated group. The high rate of failure of conservative treatment suggests that surgical intervention for symptomatic subtalar OCLs can be the primary treatment strategy; however, further research is warranted in light of the small number of patients.

Medializing Calcaneal Osteotomy for progressive collapsing foot deformity alters the three-dimensional subtalar joint alignment.

BACKGROUND: A medializing calcaneal osteotomy (MCO) is considered as one of the key inframalleolar osteotomies to correct progressive collapsing foot deformity (PCFD). While many studies were able to determine the post-operative hind- and midfoot alignment, alternations of the subtalar joint alignment remained obscured by superposition on plain radiography. Therefore, we aimed to assess the hind-, midfoot- and subtalar joint alignment pre- compared to post-operatively using 3D weightbearing CT (WBCT) imaging. METHODS: Seventeen patients with a mean age of 42 ± 17 years were retrospectively analyzed. Inclusion criteria consisted of PCFD deformity corrected by a medializing calcaneal osteotomy (MCO) as main procedure and imaged by WBCT before and after surgery. Exclusion criteria were patients who had concomitant calcaneal lengthening osteotomies, mid-/hindfoot fusions, hindfoot coalitions, and supramalleolar procedures. Image data were used to generate 3D models and compute the hindfoot (HA), midfoot (MA) - and subtalar joint (STJ) alignment in the coronal, sagittal and axial plane, as well as distance maps. RESULTS: Pre-operative measurements of the HA and MA improved significantly relative to their post-operative equivalents p < 0.05). The post-operative STJ alignment showed significant inversion (2.8° ± 1.7), abduction (1.5° ± 1.8), and dorsiflexion (2.3° ± 1.7) of the talus relative to the calcaneus (p < 0.05) compared to the pre-operative alignment. The displacement between the talus and calcaneus relative to the sinus tarsi increased significantly (0.6 mm±0.5; p < 0.05). CONCLUSION: This study detected significant changes in the sagittal, coronal, and axial plane alignment of the subtalar joint, which corresponded to a decompression of the sinus tarsi. These findings contribute to our clinical practice by demonstrating the magnitude of alteration in the subtalar joint alignment that can be expected after PCFD correction with MCO as main procedure.

Current Lack of Evidence on Treatment Strategies and Clinical Outcomes for Osteochondral Lesions of the Subtalar, Talonavicular, and Calcaneocuboid Joints: A Systematic Review.

OBJECTIVE: In contrast to osteochondral lesion (OCL) of the ankle, OCLs in other joints of the foot, such as subtalar joint, talonavicular joint, calcaneocuboid joint, and the midfoot, are rare conditions, but they can also lead to significant morbidity. The objective of this systematic review was to summarize the clinical evidence for the treatment of OCLs of the subtalar, talonavicular, calcaneocuboid, and the other midfoot joints. DESIGN: A systematic search of the MEDLINE, EMBASE, and Cochrane Library databases was performed in January 2021 based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines by 2 independent reviewers. Included studies were evaluated with regard to LOE (level of evidence) and QOE (quality of evidence). Variable reporting outcome data, clinical outcomes, and complications were evaluated. RESULTS: Seventeen studies with 21 patients were included, all of which were case reports (level 5) without any case series reporting greater than 3 patients. There were 5 patients with OCL in the subtalar joint, 15 patients in the talonavicular joint, and 1 patient in the calcaneocuboid joint. Thirteen case reports (4 subtalar joint, 8 talonavicular joint, and 1 calcaneocuboid joint) reported surgical treatment. Surgical procedures mainly included debridement, bone marrow stimulation, fixation, and bone grafting, through open or arthroscopy, all of which resulted in successful outcomes. Four case reports (1 subtalar joint, 3 talonavicular joint) reported successful conservative treatment. Other 13 case reports reported successful surgery after failed conservative treatment. No complications and reoperations were reported. CONCLUSIONS: The current systematic review revealed that there is no available evidence to ascertain clinical outcomes of both conservative and surgical treatments for cartilage lesions in the talonavicular joint, subtalar joint, and the midfoot joints, owing to the extreme paucity of literature. Both nonoperative and operative treatments can be considered, but no treatment strategies have been established.

Reconstruction of the interosseous talocalcaneal ligament using allograft for subtalar joint stabilization is effective.

PURPOSE: The aim of this study was to assess the biomechanical effects of subtalar ligament injury and reconstruction on stability of the subtalar joint in all three spatial planes. METHODS: Fifteen fresh frozen cadaveric legs were used, with transfixed tibiotalar joints to isolate motion to the subtalar joint. An arthrometer fixed to the lateral aspect of the calcaneus measured angular displacement in all three spatial planes on the inversion and eversion stress tests. Stress manoeuvres were tested with the intact joint, and then repeated after sequentially sectioning the inferior extensor retinaculum (IER), cervical ligament (CL), interosseous talocalcaneal ligament (ITCL), arthroscopic graft reconstruction of the ITCL, and sectioning of the calcaneo-fibular ligament (CFL). RESULTS: Sectioning the ITCL significantly increased angular displacement upon inversion and eversion in the coronal and sagittal planes. Reconstruction of the ITCL significantly improved angular stability against eversion in the axial and sagittal planes, and against inversion in the axial and coronal planes, at the zero time point after reconstruction. After sectioning the CFL, resistance to eversion decreased significantly in all three planes. CONCLUSION: Progressive injury of ligamentous stabilisers, particularly the ITCL, led to increasing angular displacement of the subtalar joint measured with the inversion and eversion stress tests, used in clinical practice. Reconstruction of the ITCL using tendon graft significantly stabilised the subtalar joint in the axial and sagittal planes against eversion and in the axial and coronal planes against inversion, immediately after surgery.

Increased ankle pain after total knee arthroplasty is associated with a preoperative lateralized gait and talar tilt, but not with ankle laxity or the range of motion of the subtalar joint.

Aims: Total knee arthroplasty (TKA) may provoke ankle symptoms. The aim of this study was to validate the impact of the preoperative mechanical tibiofemoral angle (mTFA), the talar tilt (TT) on ankle symptoms after TKA, and assess changes in the range of motion (ROM) of the subtalar joint, foot posture, and ankle laxity. Methods: Patients who underwent TKA from September 2020 to September 2021 were prospectively included. Inclusion criteria were primary end-stage osteoarthritis (Kellgren-Lawrence stage IV) of the knee. Exclusion criteria were missed follow-up visit, post-traumatic pathologies of the foot, and neurological disorders. Radiological angles measured included the mTFA, hindfoot alignment view angle, and TT. The Foot Function Index (FFI) score was assessed. Gait analyses were conducted to measure mediolateral changes of the gait line and ankle laxity was tested using an ankle arthrometer. All parameters were acquired one week pre- and three months postoperatively. Results: A total of 69 patients (varus n = 45; valgus n = 24) underwent TKA and completed the postoperative follow-up visit. Of these, 16 patients (23.2%) reported the onset or progression of ankle symptoms. Varus patients with increased ankle symptoms after TKA had a significantly higher pre- and postoperative TT. Valgus patients with ankle symptoms after TKA showed a pathologically lateralized gait line which could not be corrected through TKA. Patients who reported increased ankle pain neither had a decreased ROM of the subtalar joint nor increased ankle laxity following TKA. The preoperative mTFA did not correlate with the postoperative FFI (r = 0.037; p = 0.759). Conclusion: Approximately one-quarter of the patients developed ankle pain after TKA. If patients complain about ankle symptoms after TKA, standing radiographs of the ankle and a gait analysis could help in detecting a malaligned TT or a pathological gait.

Revision of Subtalar Joint Arthrodesis: Considerations for Bone Grafting, Fixation Constructs, and Three-Dimensional Printing.

Subtalar joint arthrodesis is a commonly used procedure for numerous pathologic conditions in the foot and ankle. Although rarely performed in isolation, this procedure can provide successful resolution of various lower-extremity complaints. There are traditional approaches to isolated subtalar joint arthrodesis; however, when these fail, the authors recommend alternatives to enhance the success of revisional surgery. These include the use of intramedullary nailing, larger harvest of autograft, and metallic wedge.

Factors influencing successful bone union of isolated subtalar arthrodesis for posttraumatic subtalar arthritis: a multicenter case series.

BACKGROUND: The purpose of this study was to find the factors influencing successful bone union for isolated subtalar arthrodesis in posttraumatic subtalar arthritis following calcaneal fracture. MATERIAL AND METHODS: We retrospectively analyzed the rate of successful bone union of 119 cases of isolated subtalar arthrodesis for posttraumatic subtalar arthritis performed at five university hospitals between January 2010 and December 2019. Multivariate logistic regression analysis was used to find the factors associated with successful bone union. Successful bone union was defined as resolution of hindfoot pain with the presence of osseous trabecular bridging involving more than 50% of the posterior facet within 6 months postoperatively. RESULTS: There were 77 (64.7%) cases of successful bone union, 11 (9.2%) cases of delayed union, 8 (6.7%) cases of questionable union, and 23 (19.3%) cases of nonunion. Use of fully threaded screws was 5.90 times [odds ratio (OR) = 5.90, 95% confidence interval (CI) = 1.42-24.49, p = 0.02] more likely to achieve successful bone union compared to the use of partially threaded screws. Use of two parallel screws or the two divergent screws were 3.71 times (OR = 3.71, 95% CI = 1.05-13.14, p = 0.04) and 4.65 times (OR = 4.65, 95% CI = 1.23-17.53, p = 0.02) more likely to achieve successful bone union compared to the use of a single screw. Use of cancellous autograft or structural autograft was 4.72 times (OR = 4.72, 95% CI = 1.17-19.06, p = 0.03) and 7.12 times (OR = 7.12, 95% CI = 1.46-34.68, p = 0.02) more likely to achieve successful bone union compared to no graft use. CONCLUSION: Use of fully threaded screws, autograft, and two screws compared to a single screw were the factors associated with successful bone union within six postoperative months after subtalar arthrodesis for the posttraumatic arthritis.

Hindfoot Arthrodeses and the Order of Joint Fixation Influence Tibiotalar Kinematics During Simulated Stance.

BACKGROUND: Although hindfoot arthrodeses relieve pain and correct deformity, they have been associated with progressive tibiotalar degeneration. The objective was to quantify changes in tibiotalar kinematics after hindfoot arthrodeses, both isolated subtalar and talonavicular, as well as double arthrodesis, and to determine if the order of joint fixation affects tibiotalar kinematics. METHODS: Hindfoot arthrodeses were performed in 14 cadaveric mid-tibia specimens. Specimens randomly received isolated fixation of the subtalar or talonavicular joint first, followed by fixation of the remaining joint for the double arthrodesis. A 6-degree-of-freedom robot sequentially simulated the stance phase of level walking for intact, isolated, and double arthrodesis conditions. Tibiotalar kinematic changes were compared for the intact and arthrodesis conditions. A subsequent analysis assessed the effect of the joint fixation order on tibiotalar kinematics. RESULTS: Isolated and double hindfoot arthrodeses increased tibiotalar plantarflexion, inversion, and internal rotation during late stance. Tibiotalar kinematics changes occurring after isolated arthrodesis remained consistent after the double arthrodesis for both the subtalar- and talonavicular-first conditions. The order of joint fixation influenced tibiotalar kinematics through some portions of stance, where the talonavicular-first double arthrodesis increased tibiotalar plantarflexion, eversion, and internal rotation compared to the subtalar-first double. CONCLUSION: Tibiotalar kinematics were modestly altered for all conditions, both isolated and double hindfoot arthrodeses. Changes in tibiotalar kinematics were consistent from the isolated to the double arthrodesis conditions and varied depending on which isolated hindfoot arthrodesis was performed first. Further research is needed to assess the clinical implications of the observed changes in tibiotalar kinematics, particularly as it pertains to the development of adjacent joint arthritis. CLINICAL RELEVANCE: These findings may correlate with clinical research that has cited hindfoot arthrodesis as a risk factor for adjacent tibiotalar arthritis. Once either the subtalar or talonavicular joint is fused, avoiding the arthrodesis of the second joint may not necessarily protect the tibiotalar joint.