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Background: Flexor hallucis longus (FHL) transfer is a well-established method for treating chronic Achilles tendon ruptures and tendinopathy. Harvesting of the FHL tendon in zone 2 results in greater length but is also associated with an increased risk of injury to the medial plantar nerve and requires an additional plantar incision. Because of the anatomic proximity of the FHL tendon to the tibial neurovascular bundle in zone 2, the purpose of this study was to investigate the risk of vascular or nerve injury with arthroscopic assisted percutaneous tenotomy in zone 2 of the FHL tendon. Methods: Endoscopically assisted percutaneous FHL transfer was performed on 10 right lower extremities from 10 cadaveric human specimens. The FHL tendon lengths and the relationship between FHL tendon and the tibial neurovascular bundle at zone 2 was analyzed. Results: We observed a complete transection of the medial plantar nerve in 1 case (10%). The mean length of the FHL tendon was 54.7 ± 9.5 mm and the mean distance from the distal stump of the FHL tendon to local neurovascular structures was 1.3 ± 0.7 mm. Conclusion: There is a risk of neurovascular injury after endoscopic FHL tenotomy in zone 2. The tenotomy site is within 2 mm of the local neurovascular structures in the majority of cases. The additional length gained from this technique is unlikely to be required for the majority of FHL tendon transfer procedures. If additional length is needed, we would recommend the use of intraoperative ultrasonography or a mini-open approach to minimize injury risk. Level of Evidence: Level V, expert opinion. [ABSTRACT FROM AUTHOR]

Background: A previous study defined the normal first metatarsal pronation angle (MPA) as <16 degrees and normal α angle as <18 degrees. The primary purpose of this study was to assess the side-to-side variation in first metatarsal pronation between feet in normal individuals. Methods: MPA and α angles were measured on standardized coronal weightbearing computed tomography slices. Paired t tests were used to test significance of mean side-to-side differences in a population of 63 normal, asymptomatic individuals. Results: The mean side-to-side difference in first metatarsal pronation was 4.3 degrees (95% CI 3.3, 5.2 degrees) for MPA and 4.9 degrees (95% CI 3.8, 6.0 degrees) for α angle. The normative range for side-to-side difference was calculated as 12 degrees for MPA and 14 degrees for α angle, as defined by 2 SDs from the mean. Conclusion: In a cohort of normal patients, the mean difference in first metatarsal pronation between sides was approximately 4 to 5 degrees based on MPA and α angle. However, considerable variation in differences was observed. These findings may be considered when assessing first metatarsal pronation using population-based values as it may influence thresholds for identifying pathology in an individual. [ABSTRACT FROM AUTHOR]

Background: Failure to identify and correct malrotation of the first metatarsal may lead to recurrent hallux valgus deformity. We aimed to identify the proportion of hallux valgus patients with increased first metatarsal pronation using weightbearing computed tomography (WBCT) and to identify the relationship with conventional radiographic measurements. Methods: WBCT scans were analyzed for 102 feet with a hallux valgus angle (HVA) and intermetatarsal angle (IMA) greater than or equal to 16 and 9 degrees, respectively. Metatarsal pronation angle (MPA), alpha angle, sesamoid rotation angle (SRA), and sesamoid position were measured on standardized coronal WBCT slices. Pronation was recorded as positive. Hindfoot alignment angle (HAA) was assessed using dedicated software. Pearson correlation and multiple regression analyses were used to assess differences between groups. Results: Mean HVA was 29.8±9.4 degrees and mean IMA was 14.1±3.7 degrees. Mean MPA was 11.9±5.8 (range 0-26) degrees and mean alpha angle was 11.9±6.8 (range −3 to 29) degrees. In a previous study, we demonstrated the upper limit of normal MPA as 16 degrees and alpha angle as 18 degrees. Based on these criteria, we identified abnormal metatarsal pronation in 32 feet (31.4%). We found a strong positive correlation between SRA and HVA/IMA (R = 0.67/0.60, respectively, P <.001). IMA and HAA weakly correlated with MPA and alpha angle (IMA: R = 0.26/0.27, respectively, P <.01; HAA: R = 0.26/0.27, respectively, P <.01). Regression analyses suggested that increasing IMA was the most significant radiographic predictor of increased pronation. In this cohort, there was no correlation between HVA or sesamoid position and MPA / alpha angle (HVA: P =.36/.12, respectively, sesamoid position, P =.86/.77, respectively). Conclusion: In this cohort of 102 feet that met plain radiographic criteria for hallux valgus deformity, first metatarsal pronation was found abnormal in 31.4% of patients. We found a weak association between the IMA and hindfoot valgus, but not the HVA. [ABSTRACT FROM AUTHOR]

Background: Weightbearing computed tomography (WBCT) can be used to assess alignment and rotation of the first metatarsal. It is unknown whether these measures remain consistent on sequential WBCTs in the same patient when a patient's standing position may be different. The aim of this study was to establish the repeatability (test-retest) of measurements of first metatarsal alignment and rotation in patients without forefoot pathology on WBCT. Methods: We retrospectively identified 42 feet in 26 patients with sequential WBCT studies less than 12 months apart. Patients with surgery between scans, previous forefoot surgery or hallux rigidus were excluded. Hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured using digitally reconstructed radiographs. Two methods of calculating metatarsal rotation (metatarsal pronation angle [MPA] and alpha angle) were measured on standardized coronal CT slices. Interobserver agreement and test-retest repeatability were assessed using intraclass correlation coefficients (ICCs). Standard error of measurement (SEM) and minimally detectable change (MDC95) were calculated. Results: Interobserver agreement was excellent for HVA and IMA (ICC 0.96 and 0.90, respectively) and was good for MPA and alpha angle (ICC 0.81 and 0.80, respectively). There was excellent test-retest repeatability for HVA (ICC=0.90) and good test-retest repeatability for IMA (ICC=0.77). There was excellent test-retest repeatability for MPA (ICC=0.91) and good test-retest repeatability for alpha angle (ICC=0.87). The MDC95 was 4.6 degrees for MPA and 6.1 degrees for alpha angle. Five percent of patients had a difference outside of the MDC95 for the alpha angle, compared with 2% for the MPA. Conclusion: Measurements of first metatarsal alignment and rotation are reliable between assessors and repeatable between sequential WBCTs in patients without forefoot pathology. Subtle differences in patient positioning during image acquisition do not significantly affect measurements, supporting the validity of this method of assessment in longitudinal patient care. Level of Evidence: Level IV, retrospective case series. [ABSTRACT FROM AUTHOR]

Background: Hallux valgus is a multiplanar deformity that is often treated on the basis of 2-dimensional (2D) parameters and radiographs. Recurrence rates after surgical correction remain high, and failure to correct pronation of the metatarsal is increasingly stipulated as being part of the problem. Multiple methods of assessing metatarsal pronation have been proposed. Methods: We performed a systematic literature review identifying studies that measured metatarsal pronation and torsion on computed tomography (CT) scans. Specific methodology, patient groups, results, and reliability assessments were all reported. Results: We identified 14 studies that fulfilled the inclusion criteria. Eleven studies measured 2D values on CT scan, and 3 studies used computer-based 3-dimensional (3D) modeling and artificial intelligence systems to help calculate pronation. Metatarsal pronation angle, α angle, sesamoid rotation angle, and measurements for torsion were the most commonly used methods. All angles and measurements were performed as 2D measurements, but the metatarsal pronation angle was also performed with 3D modeling. Reliability and reproducibility of the α angle and metatarsal pronation angle were excellent, despite being performed on studies with small numbers. Conclusion: Multiple methods have been reported to demonstrate first metatarsal pronation on CT, of which the α angle and the metatarsal pronation angle are the most pragmatic and useful in a clinical setting. Further work is needed to further validate the reliability of these measurements in larger series and to identify normal pronation and metatarsal torsion on weightbearing imaging. Further work is required to determine whether addressing pronation reduces recurrence rates and improves outcomes in surgery for hallux valgus. Level of Evidence: Level III, retrospective cohort study. [ABSTRACT FROM AUTHOR]

Background: The importance of the rotational profile of the first metatarsal is increasingly recognized in the surgical planning of hallux valgus. However, rotation in the normal population has only been measured in small series. We aimed to identify the normal range of first metatarsal rotation in a large series using weightbearing computed tomography (WBCT). Methods: WBCT scans were retrospectively analyzed for 182 normal feet (91 patients). Hallux valgus angle, intermetatarsal angle, anteroposterior/lateral talus–first metatarsal angle, calcaneal pitch, and hindfoot alignment angle were measured using digitally reconstructed radiographs. Patients with abnormal values for any of these measures and those with concomitant pathology, previous surgery, or hallux rigidus were excluded. Final assessment was performed on 126 feet. Metatarsal pronation (MPA) and α angles were measured on standardized coronal computed tomography slices. Pronation was recorded as positive. Intraobserver and interobserver reliability were assessed using intraclass correlation coefficients (ICCs). Results: Mean MPA was 5.5 ± 5.1 (range, –6 to 25) degrees, and mean α angle was 6.9 ± 5.5 (range, –5 to 22) degrees. When considering the normal range as within 2 standard deviations of the mean, the normal range identified was −5 to 16 degrees for MPA and −4 to 18 degrees for α angle. Interobserver and intraobserver reliability were excellent for both MPA (ICC = 0.80 and 0.97, respectively) and α angle (ICC = 0.83 and 0.95, respectively). There was a moderate positive correlation between MPA and α angle (Pearson coefficient 0.68, P <.001). Conclusion: Metatarsal rotation is variable in normal feet. Normal MPA can be defined as less than 16 degrees, and normal α angle can be defined as less than 18 degrees. Both MPA and α angle are reproducible methods for assessing rotation. Further work is needed to evaluate these angles in patients with deformity and to determine their significance when planning surgical correction of hallux valgus. Level of Evidence: Level III, retrospective comparative study. [ABSTRACT FROM AUTHOR]

Triceps tendon ruptures and avulsions are rare injuries and are often associated with systemic diseases. This paper illustrates the unique case of a 20-year-old female patient with pseudohypoparathyroidism, who sustained bilateral triceps avulsion fractures after a fall. She underwent suture anchor fixation, augmented with tension band suture as double row repair with excellent post-operative results. We describe the pathophysiology of this injury and the unique method of fixation, which can be an alternative effective method to repair these injuries. [ABSTRACT FROM AUTHOR]

Background: Coronal plane ankle joint alignment is typically assessed using the tibiotalar angle (TTA), which relies on the anatomical axis of the tibia (AAT) and the articular surface of the talus as landmarks. Often, the AAT differs from the mechanical axis of the lower limb (MAL). We set out to test our hypothesis that the TTA using the MAL would differ from the TTA measured using the AAT in patients with ankle osteoarthritis. Methods: Standardized standing long leg radiographs of 61 ankles with end-stage osteoarthritis were analyzed. We measured the MAL and the AAT. A line was drawn along the talar articular surface (TA) and the TTA was calculated using both the MAL (MAL-TA) and the AAT (AAT-TA). The mechanical axis of the tibia (MAT) was also recorded and the MAL-MAT angle calculated. The difference between MAL-TA and AAT-TA and its correlation with the MAL-MAT angle were assessed. Intra- and interobserver agreement were measured for MAL-TA and AAT-TA. Results: The mean MAL-TA was 91.4 degrees (95% CI, 88.5-94.4) and the mean AAT-TA was 91.2 degrees (95% CI, 88.6-93.9). The difference ranged from −8.1 to 7.8 degrees, and was greater than 2 and 3 degrees in 42% and 18% of the patients, respectively. The difference, as an absolute value, also strongly correlated with the MAL-MAT angle (r = 0.91, P <.001). Intra- and interobserver reliability were excellent for both MAL-TA (intraclass correlation coefficient [ICC], 0.93 and 0.91, respectively) and AAT-TA (ICC, 0.91 and 0.89, respectively). Conclusion: We recommend that surgeons consider using the MAL-TA, which relies on long leg radiographs, especially with proximal deformity, to more accurately measure coronal plane ankle joint alignment. Level of Evidence: Level III, retrospective comparative study. [ABSTRACT FROM AUTHOR]

Background: Total ankle replacements (TARs) have higher rates of osteolysis than hip or knee replacements. It is unclear whether this is a pathologic immunologic process in response to wear debris, or expansion of pre-existing osteoarthritic bone cysts. We aimed to determine the incidence of bone cysts in patients with end-stage ankle arthritis prior to surgery and review the literature on bone cysts and osteolysis in relation to TAR. Methods: This is a descriptive/prevalence study in which all patients with end-stage ankle arthritis underwent plain radiographic imaging and computed tomographic (CT) scans prior to TAR surgery. Their imaging was assessed for the presence of cysts, measured on sagittal, axial, and coronal slices of the CT scan at the widest diameter. All cysts that would be removed as a result of the bone resection for the implant were excluded using digital analysis software. We assessed 120 consecutive patients with mean age of 63.4 years. Results: Seventeen patients (14%) did not have any bone cysts based on CT images. Ten patients (8%) had cysts that would have been completely removed by surgery, leaving 93 patients for analysis (78%). In 60% of these cases, the cysts were not seen on the plain radiographs. In 39 patients (33%), the cysts were greater than 5 mm in size. The medial (36%) and lateral malleoli (33%) were the most common location for the cysts (mean diameter 4.6±2.0 and 4.2±2.3 mm, respectively). Conclusion: Bone cysts outside of the resection margins for a TAR were present in 78% of patients with ankle arthritis prior to undergoing surgery. In 30% of cases, cysts were greater than 5 mm in size. In 60% of cases, the cysts were not seen on plain radiographs. Preoperative 3-dimensional imaging can provide a foundation to observe and quantify cyst presence, expansion, and time of onset in the postoperative setting. Level of Evidence: Level IIc, diagnostic/prevalence study. [ABSTRACT FROM AUTHOR]

Background: The importance of total ankle replacement (TAR) implant orientation in the axial plane is poorly understood with major variation in surgical technique of implants on the market. Our aim was to better understand the axial rotational profile of patients undergoing TAR. Methods: In 157 standardized computed tomography (CT) scans of patients with end-stage ankle arthritis planning to undergo primary TAR surgery, we measured the relationship between the knee posterior condylar axis, the tibial tuberosity, the transmalleolar axis (TMA), and the tibiotalar angle. The foot position was measured in relation to the TMA with the foot plantigrade. The variation between the medial gutter line and the line bisecting both gutters was assessed. Results: The mean external tibial torsion was 34.5 ± 10.3 degrees (11.8-62 degrees). When plantigrade, the mean foot position relative to the TMA was 21 ± 10.6 degrees (0.7-38.4 degrees) internally rotated. As external tibial torsion increased, the foot position became more internally rotated relative to the TMA (Pearson correlation, 0.6; P <.0001). As the tibiotalar angle became more valgus, the foot became more externally rotated relative to the TMA (Pearson correlation, −0.4; P <.01). The mean difference between the medial gutter line and a line bisecting both gutters was 4.9 ± 2.8 degrees (1.7-9.4 degrees). More than 51% of patients had a difference greater than 5 degrees. The mean angle between the medial gutter line and a line perpendicular to the TMA was 7.5 ± 2.6 degrees (2.8-13.7 degrees). Conclusion: There was a large variation in rotational profile of patients undergoing TAR, particularly between the medial gutter line and the TMA. Surgeon designers and implant manufacturers should develop consistent methods to guide surgeons toward judging the appropriate axial rotation of their implant on an individual basis. We recommend careful clinical assessment and preoperative CT scans to enable the correct rotation to be determined. Level of Evidence: Level IIc, outcomes research. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: Multi-centre assessment of utilisation and outcomes of hindfoot intramedullary fixation (HFN) or fibula pro-tibial screw fixation (PTS) in complex ankle fractures. Methods: From January 2020 - June 2021, demographic data, co-morbidities, was collected on all patients undergoing HFN or PTS for an AO44 ankle fracture at three Major Trauma Centre's (MTC's) in the UK. Outcomes of interest included postoperative complications, Charlson-Co-morbidity-Index-Score (CCIS), weight-bearing status, peri-operative information, soft tissue management and post-operative complications were recorded, Radiographs were assessed for metalwork breakage and anatomical reduction (Pettrone Criteria). Results: 77 patients were identified; 59 underwent HFN and 18 had PTS fixation. The mean age differed between techniques (80+-11.4 [HFN] vs. 66+-19.8 [PTS]) (p<0.001) and 10-year survival favoured patients undergoing PTS (30+-31.6% in the [HFN] and 55+-37.6%[PTS] (p<0.004). 17 (29%) HFN patients had diabetes compared with 7 (39%) PTS patients. 36 (61%) HFN's were open fractures, 7 (39%) PTS's were open fractures, differences in outcomes between primary closure/shortening/joint preparation and combined ortho-plastic management were noted in the HFN group.Time to full weight bearing was reduced in HFN vs. PTS (2.1+-3.1 vs. 8.0+-5.0) (p<0.001), only a minority of patients were allowed to WB immediately. 12 (27%) of patients with open fractures had post-operative complications compared with 5 (15%) of closed fractures. The mean Pettrone score for HFN was 1.3+-1.6 compared with 3.7+-0.6 for PTS, subgroup analysis showed Pettrone scores for open fractures treated with a HFN worsened(0.9 vs 2.3) (p=0.007). Conclusion: Comparing functional and outcome rates between the 2 techniques, PTS provides stable fixation, and a lower overall complication rates, with better radiological outcomes and expected survival. However, HFN is performed in frailer patients, with co-morbidities where early weight-bearing may be beneficial, accepting limited functionality and higher complication rate. Even though both techniques are designed for early mobility in the appropriate person this is not always realised, thus further studies are required to characterise which patients benefit most from each surgical technique. [ABSTRACT FROM AUTHOR]