Wireless Measurements Using Electrical Impedance Spectroscopy to Monitor Fracture Healing.

There is an unmet need for improved, clinically relevant methods to longitudinally quantify bone healing during fracture care. Here we develop a smart bone plate to wirelessly monitor healing utilizing electrical impedance spectroscopy (EIS) to provide real-time data on tissue composition within the fracture callus. To validate our technology, we created a 1-mm rabbit tibial defect and fixed the bone with a standard veterinary plate modified with a custom-designed housing that included two impedance sensors capable of wireless transmission. Impedance magnitude and phase measurements were transmitted every 48 h for up to 10 weeks. Bone healing was assessed by X-ray, µCT, and histology. Our results indicated the sensors successfully incorporated into the fracture callus and did not impede repair. Electrical impedance, resistance, and reactance increased steadily from weeks 3 to 7-corresponding to the transition from hematoma to cartilage to bone within the fracture gap-then plateaued as the bone began to consolidate. These three electrical readings significantly correlated with traditional measurements of bone healing and successfully distinguished between union and not-healed fractures, with the strongest relationship found with impedance magnitude. These results suggest that our EIS smart bone plate can provide continuous and highly sensitive quantitative tissue measurements throughout the course of fracture healing to better guide personalized clinical care.

Methods for Biomechanical Testing of Posterior Malleolar Fractures in Ankle Fractures: A Scoping Review.

BACKGROUND: The treatment of posterior malleolar fractures (PMFs) is debated, including the need for surgery and method of fixation. Recent literature has suggested that fracture pattern, rather than fragment size, may be an important predictor for ankle biomechanics and functional outcome. Biomechanical studies have been conducted to provide evidence-based treatment on the effects of fracture and fixation on contact pressure and stability. The objective of this scoping review is to summarize the methodologies used in biomechanical studies on PMFs and assess whether they are sufficient to test the need for surgery and method of fixation. METHODS: A scoping review of publications before January 2022 was performed. PubMed/Medline and Embase Ovid were searched for cadaver or finite element analysis (FEA) studies that created and tested the effects of PMFs in ankle fractures. Both cadaver and FEA studies were included. Data about fragment characteristics, mode of testing, and outcomes were charted by 2 persons from the study group. The data were synthesized when possible and compared. RESULTS: We included 25 biomechanical studies, including 19 cadaver studies, 5 FEA studies, and 1 cadaver and FEA study. Aside from the fragment size, few other fragment characteristics were reported. Mode of testing varied with different loads and foot positions. Strong conclusions on the effects of fracture and fixation on contact pressure and stability could not be made. CONCLUSION: Biomechanical studies on PMFs demonstrate wide variability in fragment characteristics and mode of testing, which makes it difficult to compare studies and draw conclusions on the need for surgery and method of fixation. Additionally, limited reporting of fragment measurements questions the applicability to clinical practice. The biomechanical literature on PMFs would benefit from the use of a standard classification and universal fragment measurements to match clinical injuries in future biomechanical studies. Based on this review, we recommend the Mason classification, which addresses the pathomechanism, and use of the following fragment measurements in all 3 anatomic planes when creating and describing PMFs: fragment length ratio, axial angle, sagittal angle or fragment height, and interfragmentary angle. The testing protocol needs to reflect the purpose of the study. CLINICAL RELEVANCE: This scoping review demonstrates wide methodological diversity of biomechanical studies. Consistency in methodology should enable comparison of study results, leading to stronger evidence-based recommendations to guide surgeons in decision making and offer PMF patients the best treatment.

The Biomechanical Role of the Deltoid Ligament on Ankle Stability: Injury, Repair, and Augmentation.

BACKGROUND: Deltoid ligament injuries occur in isolation as well as with ankle fractures and other ligament injuries. Both operative treatment and nonoperative treatment are used, but debate on optimal treatment continues. Likewise, the best method of surgical repair of the deltoid ligament remains unclear. PURPOSE: To determine the biomechanical role of native anterior and posterior components of the deltoid ligament in ankle stability and to determine the efficacy of simple suture versus augmented repair. STUDY DESIGN: Controlled laboratory study. METHODS: Ten cadaveric ankles (mean age, 51 years; age range, 34-64 years; all male specimens) were mounted on a 6 degrees of freedom robotic arm. Each specimen underwent biomechanical testing in 8 states: (1) intact, (2) anterior deltoid cut, (3) anterior repair, (4) tibiocalcaneal augmentation, (5) deep anterior tibiotalar augmentation, (6) posterior deltoid cut, (7) posterior repair, and (8) complete deltoid cut. Testing consisted of anterior drawer, eversion, and external rotation (ER), each performed at neutral and 25° of plantarflexion. A 1-factor, random-intercepts, linear mixed-effect model was created, and all pairwise comparisons were made between testing states. RESULTS: Cutting the anterior deltoid introduced ER (+2.1°; P = .009) and eversion laxity (+6.2° of eversion; P < .001) at 25 degrees of plantarflexion. Anterior deltoid repair restored native ER but not eversion. Tibiocalcaneal augmentation reduced eversion laxity, but tibiotalar augmentation provided no additional benefit. The posterior deltoid tear showed no increase in laxity. Complete tear introduced significant anterior translation, ER, and eversion laxity (+7.6 mm of anterior translation, +13.8° ER and +33.6° of eversion; P < .001). CONCLUSION: A complete deltoid tear caused severe instability of the ankle joint. Augmented anterior repair was sufficient to stabilize the complete tear, and no additional benefit was provided by posterior repair. For isolated anterior tear, repair with tibiocalcaneal augmentation was the optimal treatment. CLINICAL RELEVANCE: Deltoid repair with augmentation may reduce or avoid the need for prolonged postoperative immobilization and encourage accelerated rehabilitation, preventing stiffness and promoting earlier return to preinjury activity.

Higher complication rate after nail compared with plate fixation of ankle fractures in patients aged 60 years or older: a prospective, randomized controlled trial.

AIMS: The aim of this study was to compare the functional and radiological outcomes and the complication rate after nail and plate fixation of unstable fractures of the ankle in elderly patients. METHODS: In this multicentre study, 120 patients aged ≥ 60 years with an acute unstable AO/OTA type 44-B fracture of the ankle were randomized to fixation with either a nail or a plate and followed for 24 months after surgery. The primary outcome measure was the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score. Secondary outcome measures were the Manchester-Oxford Foot Questionnaire, the Olerud and Molander Ankle score, the EuroQol five-dimension questionnaire, a visual analogue score for pain, complications, the quality of reduction of the fracture, nonunion, and the development of osteoarthritis. RESULTS: At 24 months, the median AOFAS score was equivalent in the two groups (nail 90 (interquartile range (IQR) 82 to 100), plate 95 (IQR 87 to 100), p = 0.478). There were statistically more complications and secondary operations after nail than plate fixation (p = 0.024 and p = 0.028, respectively). There were no other significant differences in the outcomes between the two groups. CONCLUSION: The functional outcome after nail and plate fixation was equivalent; however, the complication rate and number of secondary operations was significantly higher after nail fixation. These results suggest that plate fixation should usually be the treatment of choice for unstable ankle fractures in the elderly.Cite this article: Bone Joint J 2023;105-B(1):72-81.

Outcomes Following Repair of Achilles Midsubstance Tears: Percutaneous Knotless Repair vs Open Repair.

BACKGROUND: Optimum treatment for acute Achilles tendon rupture results in high mechanical strength, low risk of complications, and return to preinjury activity level. Percutaneous knotless repair is a minimally invasive technique with promising results in biomechanical studies, but few comparison clinical studies exist. Our study purpose was to compare functional outcomes and revision rates following acute Achilles tendon rupture treated between percutaneous knotless repair and open repair techniques. METHODS: Patients 18 years or older with an acute Achilles tendon rupture, treated by a single surgeon with either open repair or percutaneous knotless repair, and more than 2 years after surgery were assessed for eligibility. Prospective clinical data were obtained from the data registry and standard electronic medical record. Additionally, the patients were contacted to obtain current follow-up questionnaires. Primary outcome measure was Foot and Ankle Ability Measure (FAAM) activities of daily living (ADL). Secondary outcome measures were FAAM sports, 12-Item Short Form Health Survey (SF-12), Tegner activity scale, patient satisfaction with outcome, complications, and revisions. Postoperative follow-up closest to 5 years was used in this study. RESULTS: In total, 61 patients were included in the study. Twenty-four of 29 patients (83%) in the open repair group and 28 of 32 patients (88%) in the percutaneous knotless repair group completed the questionnaires with average follow-up of 5.8 years and 4.2 years, respectively. We found no significant differences in patient-reported outcomes or patient satisfaction between groups (FAAM ADL: 99 vs 99 points, P = .99). Operative time was slightly longer in the percutaneous knotless repair group (46 vs 52 minutes, P = .02). Two patients in the open group required revision surgery compared to no patients in the percutaneous group. CONCLUSION: In our study, we did not find significant differences in patient-reported outcomes or patient satisfaction by treating Achilles tendon midsubstance ruptures with percutaneous knotless vs open repair. LEVEL OF EVIDENCE: Level IlI, retrospective cohort study.

Biomechanical Evaluation of Achilles Tendon Midsubstance Repair: The Effects of Anchor Angle and Position.

BACKGROUND: The percutaneous knotless repair technique for Achilles tendon ruptures utilizes a Percutaneous Achilles Repair System (PARS) device for suturing the proximal tendon and 2 suture anchors for fixing the sutures into the calcaneus. Determining the best position of the suture anchors may optimize the strength of this repair. METHODS: Twelve pairs of human ankle cadaveric specimens were randomly assigned to receive suture anchors placed at 45°, 90°, or 135° from the sagittal plane. The anchors were tensioned according to a protocol representing progressive, postoperative rehabilitation. Load, number of loading cycles, displacement, and mode of failure were recorded. RESULTS: With the anchors placed at 45°, 90°, and 135°, the ultimate failure loads were mean 265 ± 64 N, 264 ± 75 N, and 279 ± 40 N, and the total number of loading cycles were mean 459 ± 166, 466 ± 158, and 469 ± 110, respectively. The effect of anchor angle on failure load, number of loading cycles, and displacement was not statistically significant. Visually, the anchors at 45° and 90° demonstrated sutures cutting through the bone. CONCLUSION: We found no statistically significant difference in pullout strength between the 3 different anchor angles. Sutures cutting through the bone may be a concern with acute anchor angles. This suggests that a 135° anchor angle may result in a lower risk of tendon elongation with the percutaneous knotless repair technique. LEVELS OF EVIDENCE: Cadaveric laboratory study.

Relationship Between Tibiotalar Joint Space and Ankle Function Following Ankle Surgery.

BACKGROUND: Joint-preserving procedures of the ankle may postpone the need for ankle arthrodesis (AA) or total ankle replacement (TAR). The challenge for the surgeon is to determine which patients may benefit from these joint-preserving procedures. We hypothesized that patents with less than 2 mm of ankle joint space on preoperative radiographs would report inferior outcomes following joint-preserving surgery compared with those with 2 mm or greater joint space. METHODS: Patients 18 years of age or older treated with joint-preserving ankle surgery with a minimum of 2 years of follow-up were considered for study inclusion. The ankle joint space was measured on standardized weightbearing preoperative radiographs. At follow-up, patients completed questionnaires including the Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL) and Sports subscales, the Short Form-12 (SF-12) Physical Component Summary and Mental Component Summary, the Tegner Activity Scale, and satisfaction with outcome. RESULTS: A total of 251 patients were included in the study. Forty-three patients had an ankle joint space of less than 2 mm. Compared with the 208 patients with an ankle joint space of 2 mm or greater, they had inferior FAAM ADL, FAAM Sports, and SF-12 Physical Component Summary scores (P = .001, P = .001, and P = .006, respectively). Additionally, a statistically significant positive correlation between joint space distance and the FAAM ADL (P = .012, r = 0.158), FAAM Sports (P < .001, r = 0.301), and SF-12 Physical Component Summary (P < .010, r = 0.163) scores was found. CONCLUSION: Patients with a preoperatively narrowed ankle joint space of less than 2 mm had significantly lower outcome scores following joint-preserving ankle surgery compared with patients with preserved ankle joint space. These results may assist clinicians in selecting patients who may benefit from ankle joint-preserving procedures, as well as counseling patients with a narrowed ankle joint space regarding expected outcome after joint-preserving ankle surgery. LEVEL OF EVIDENCE: Level II, prognostic comparative study.

Accuracy of MRI-Based Talar Cartilage Thickness Measurement and Talus Bone and Cartilage Modeling: Comparison with Ground-Truth Laser Scan Measurements.

OBJECTIVE: The purpose of this work was to compare measurements of talar cartilage thickness and cartilage and bone surface geometry from clinically feasible magnetic resonance imaging (MRI) against high-accuracy laser scan models. Measurement of talar bone and cartilage geometry from MRI would provide useful information for evaluating cartilage changes, selecting osteochondral graft sources or creating patient-specific joint models. DESIGN: Three-dimensional (3D) bone and cartilage models of 7 cadaver tali were created using (1) manual segmentation of high-resolution volumetric sequence 3T MR images and (2) laser scans. Talar cartilage thickness was compared between the laser scan- and MRI-based models for the dorsal, medial, and lateral surfaces. The laser scan- and MRI-based cartilage and bone surface models were compared using model-to-model distance. RESULTS: Average cartilage thickness within the dorsal, medial, and lateral surfaces were 0.89 to 1.05 mm measured with laser scanning, and 1.10 to 1.22 mm measured with MRI. MRI-based thickness was 0.16 to 0.32 mm higher on average in each region. The average absolute surface-to-surface differences between laser scan- and MRI-based bone and cartilage models ranged from 0.16 to 0.22 mm for bone (MRI bone models smaller than laser scan models) and 0.35 to 0.38 mm for cartilage (MRI bone models larger than laser scan models). CONCLUSIONS: This study demonstrated that cartilage and bone 3D modeling and measurement of average cartilage thickness on the dorsal, medial, and lateral talar surfaces using MRI were feasible and provided similar model geometry and thickness values to ground-truth laser scan-based measurements.

Minimally Invasive Achilles Repair Techniques.

Achilles tendon rupture is an increasingly common problem with an aging population participating in high-level physical activities. Appropriate treatment has been debated for decades, but good outcomes have been reported after conservative and surgical management. The development of minimally invasive surgical techniques for Achilles repair has reduced the incidence of complications and maintained the high level of function reported after open surgery. The Achilles Midsubstance SpeedBridge repair is a newer minimally invasive technique that has demonstrated promising results and is the authors' preferred treatment of Achilles tendon rupture in athletes and active patients.