Pediatric elbow measurement parameters: Evaluation of the six angles in inter- and intra-observer reliability.

BACKGROUND: Several radiographic measurements of the humerus can be used to evaluate the treatment outcome of supracondylar fractures in children. Because of the cartilaginous nature of the immature elbow, interpretation of radiographs around this area is sometimes challenging and can be unreliable. This study was conducted to determine the inter-observer and intra-observer reliability of the six commonly used radiographic measurements of the distal humerus. METHOD: The Baumann angle, humero-ulna angle, metaphyseal-diaphyseal angle, radial epiphyseal angle, shaft-condylar angle and lateral capitellohumeral angle of the humerus were measured by two observers on the radiographs of uninjured elbows from 58 children. The values between each measurement were compared and correlated using a Pearson coefficient of correlation to determine the inter-observer and intra-observer reliability. RESULTS: All of the radiographic parameters showed excellent intra-observer reliability with the correlation coefficient values of the Baumann angle, humero-ulna angle, metaphyseal-diaphyseal angle, radial epiphyseal angle, shaft-condylar angle, lateral capitellohumeral angle as 0.945, 0.95, 0.909, 0.888, 0.961 and 0.975 (p < 0.001), respectively. The inter-observer reliability of the Baumann and humero-ulna angles were also found to be highly correlated at r = 0.843 (p < 0.001) and 0.878 (p < 0.001), respectively. The metaphyseal-diaphyseal angle had poor reliability with r = 0.136 (p = 0.291) while the radial epiphyseal angle, shaft-condylar angle, and lateral capitellohumeral angle demonstrated good reliability with r = 0.675 (p < 0.001), 0.747 (p < 0.001), and 0.686 (p < 0.001), respectively. CONCLUSION: The Baumann angle and humero-ulna angle measurements of distal humerus showed excellent inter- and intra-observer reliability. Both parameters represent repeatable and reliable methods for determining the outcome of supracondylar humeral fractures in pediatric population.

Surgical correction of coxa vara: Evaluation of neck shaft angle, Hilgenreiner-epiphyseal angle for indication of recurrence.

BACKGROUND: Coxa vara is a hip deformity in which the femoral neck-shaft angle decreases below its normal value. Standard surgical treatment for this condition is corrective valgus osteotomy. Appropriate correction of the Hilgenreiner-epiphyseal angle is important to prevent recurrence. The purpose of this study is to: 1) evaluate the recurrence of the deformity at the latest follow up; and 2) find the appropriate angle of correction associated with the lowest recurrence. METHODS: 34 hips in 31 patients who underwent surgery for treatment of coxa vara from 2005 to 2014 were included. Patient-reported outcomes, Hilgenreiner-epiphyseal angle, and neck-shaft angle were assessed preoperatively, postoperatively, and at latest follow-up. RESULTS: The mean age at surgery was 10.99, with a range of 5-30, years. Preoperative neck-shaft angle ranged from 60 to 100 degrees, and Hilgenreiner-epiphyseal angle ranged from 60 to 90 degrees. At the latest follow up, the neck-shaft angle ranged from 120 to 135 degrees and the Hilgenreiner-epiphyseal angle ranged from 22 to 35 degrees (p < 0.001). The Harris hip score improved from 47.20 (34-66) to 79.68 (60-100) (p < 0.001). There was no recurrence of deformities at the mean follow up of 37.87 months. CONCLUSION: Surgical correction of coxa vara in various pathologies can be done successfully with the Hilgenreiner-epiphyseal angle corrected to ≤ 35 degrees or the neck shaft angle corrected to > 120 degrees in order to prevent recurrence of the deformity. Majority of the patients were reported improvement of hip function. However, a longer-term follow up is required to determine further outcomes regarding to recurrence of the deformity.

Transcortical or intracondylar? Which model is accurate for predicting biomaterial attachment in total joint replacement?

Despite four decades of research on material and porous coatings intended for cementless fixation in total joint replacement (TJR), aseptic mechanical loosening unrelated to particulate disease remains a concern. One main question asked is how translational are the animal models used to screen material and porous coatings intended for TJR fixation? Another question is how specific are the translational models at targeting the cementless TJR components that have the highest loosening rates? The hypothesis tested was that the bone response would be different between the two bone types-cortical and cancellous-used in translational animal modeling. The osteoblastic jumping distance (OJD), percent ingrowth, and appositional bone response were measured to assess the response between cancellous and cortical bone at two different anatomical locations, within the same limb. With 500 µm inset, titanium porous coated implants and negative control dinosaur (coprolite) implants were investigated. The data demonstrated that cortical bone had 7 times OJD than cancellous bone. The bone ingrowth data demonstrated 16 times higher bone ingrowth than the cancellous bone. Light microscopy showed predominately fibrous tissue attachment (98%) in cancellous bone. Screening of materials intended for TJR require a translational model predictive of the clinical condition. The results demonstrated that the transcortical model rendered false-positive data. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 578-588, 2018.

Potential risk factors for birth fractures: a case-control study.

INTRODUCTION AND HYPOTHESIS: Birth fractures are uncommon but remain a concern among obstetricians. Although such fractures usually heal without long-term sequelae, some are associated with lifelong disabilities, such as brachial plexus injuries. The purpose of this study was primarily to investigate risk factors related to birth fractures. METHODS: This study comprised newborns delivered at our institute between 2003 and 2013. All 46 birth fractures were reviewed and compared with 223 randomly selected normal neonates. Demographic data of newborns and their mothers, as well as the details of delivery and fracture characteristics, were recorded. Univariate and multiple logistic regression analyses were applied to differentiate the risk factors. RESULTS: Forty-six babies had birth fractures, and 223 babies were without fracture. Forty-five cases were midclavicular fractures and one was a humeral-shaft fracture. Babies with a fracture had significantly higher birthweight and length and were larger for gestational age (p ≤ 0.001 for all factors). After multivariate analysis, parameters that remained significantly correlated with higher fracture risk included nurse attendant [odds ratio (OR) 34.8, p = 0.004], large for gestational age (OR 12.1, p < 0.001), instrumented delivery (OR 10.62, p < 0.001), and meconium stain (OR 3.10, p = 0.004). A high Apgar score at one minute and cesarean delivery were associated with decreased fracture risk (OR 0.39, p = 0.004 and OR 0.12, p = 0.001, respectively). CONCLUSIONS: Patient (including large for gestational age) and peripartum (including meconium stain, shoulder dystocia, instrumented delivery, and nurse attendant) factors were associated with a higher risk of birth fracture. Factors related to a decreased risk were a high Apgar score at one minute and cesarean delivery. Careful prenatal assessments are recommended to evaluate the risk of birth fracture and prompt cesarean section for patients at high risk.

Factors Affecting the Outcomes of Uncomplicated Primary Open Ankle Arthrodesis.

BACKGROUND: The objective of this study was to identify factors influencing operative outcomes in straightforward, uncomplicated open ankle fusions. METHODS: We reviewed all primary open ankle fusions conducted at 1 institution over an 11-year period to identify straightforward, uncomplicated open ankle fusions. Inclusion required a minimum of 6 months follow-up. Patients were excluded for neuropathic arthropathy, insensate limb, failed total ankle replacement, simultaneous arthrodesis of the subtalar joint, or fusions performed within 1 year of injury to salvage failed fixation and painful function due to (1) open fractures, (2) segmental bone loss greater than 1 cm, (3) infection, or (4) talar body fractures. The primary outcome variable was radiographic union at 6 months. Other operative complications were analyzed as secondary outcomes. Five hundred twenty-eight ankle fusion surgeries were performed on 440 patients at 1 institution during the study period. Two hundred fifteen surgeries met inclusion/exclusion eligibility criteria for uncomplicated open ankle fusions. RESULTS: The overall union rate was 91%. In this cohort of uncomplicated open ankle fusions, bivariate analysis over a broad range of potential factors and further focused multivariate analysis found that nonunion was more than 3 times more likely to occur after previous subtalar fusion, and 2 times more likely to occur in patients with preoperative varus ankle alignment. The rate of reoperation was 19%, with nonunion revision as the leading reason, followed by hardware removal and incision and drainage for presumed infection. Diabetes was not a significant risk factor of either deep or superficial infection. CONCLUSION: Open ankle fusion failed in 9% of uncomplicated ankles with arthritis. Patients who had an open ankle fusion done after previous subtalar joint fusion, as well as those who had preoperative varus ankle alignment, had a significantly higher rate of nonunion. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Does the subtalar joint compensate for ankle malalignment in end-stage ankle arthritis?

BACKGROUND: Patients with ankle arthritis often present with concomitant hindfoot deformity, which may involve the tibiotalar and subtalar joints. However, the possible compensatory mechanisms of these two mechanically linked joints are not well known. QUESTIONS/PURPOSES: In this study we sought to (1) compare ankle and hindfoot alignment of our study cohort with end-stage ankle arthritis with that of a control group; (2) explore the frequency of compensated malalignment between the tibiotalar and subtalar joints in our study cohort; and (3) assess the intraobserver and interobserver reliability of classification methods of hindfoot alignment used in this study. METHODS: Between March 2006 and September 2013, we performed 419 ankle arthrodesis and ankle replacements (380 patients). In this study, we evaluated radiographs for 233 (56%) ankles (226 patients) which met the following inclusion criteria: (1) no prior subtalar arthrodesis; (2) no previously failed total ankle replacement or ankle arthrodesis; (3) with complete conventional radiographs (all three ankle views were required: mortise, lateral, and hindfoot alignment view). Ankle and hindfoot alignment was assessed by measurement of the medial distal tibial angle, tibial talar surface angle, talar tilting angle, tibiocalcaneal axis angle, and moment arm of calcaneus. The obtained values were compared with those observed in the control group of 60 ankles from 60 people. Only those without obvious degenerative changes of the tibiotalar and subtalar joints and without previous surgeries of the ankle or hindfoot were included in the control group. Demographic data for the patients with arthritis and the control group were comparable (sex, p=0.321; age, p=0.087). The frequency of compensated malalignment between the tibiotalar and subtalar joints, defined as tibiocalcaneal angle or moment arm of the calcaneus being greater or smaller than the same 95% CI statistical cutoffs from the control group, was tallied. All ankle radiographs were independently measured by two observers to determine the interobserver reliability. One of the observers evaluated all images twice to determine the intraobserver reliability. RESULTS: There were differences in medial distal tibial surface angle (86.6°±7.3° [95% CI, 66.3°-123.7°) versus 89.1°±2.9° [95% CI, 83.0°-96.3°], p<0.001), tibiotalar surface angle (84.9°±14.4° [95% CI, 45.3°-122.7°] versus 89.1°±2.9° [95% CI, 83.0°-96.3°], p<0.001), talar tilting angle (-1.7°±12.5° [95% CI, -41.3°-30.3°) versus 0.0°±0.0° [95% CI, 0.0°-0.0°], p=0.003), and tibiocalcaneal axis angle (-7.2°±13.1° [95% CI, -57°-33°) versus -2.7°±5.2° [95% CI, -13.3°-9.0°], p<0.001) between patients with ankle arthritis and the control group. Using the classification system based on the tibiocalcaneal angle, there were 62 (53%) and 22 (39%) compensated ankles in the varus and valgus groups, respectively. Using the classification system based on the moment arm of the calcaneus, there were 68 (58%) and 20 (35%) compensated ankles in the varus and valgus groups, respectively. For all conditions or methods of measurement, patients with no or mild degenerative change of the subtalar joint have a greater likelihood of compensating coronal plane deformity of the ankle with arthritis (p<0.001-p=0.032). The interobserver and intraobserver reliability for all radiographic measurements was good to excellent (the correlation coefficients range from 0.820 to 0.943). CONCLUSIONS: Substantial ankle malalignment, mostly varus deformity, is common in ankles with end-stage osteoarthritis. The subtalar joint often compensates for the malaligned ankle in static weightbearing. LEVEL OF EVIDENCE: Level III, diagnostic study.

Deep transverse metatarsal ligament and static stability of lesser metatarsophalangeal joints: a cadaveric study.

BACKGROUND: The static support that guides motion around the lesser metatarsophalangeal joints (MTPJs) is complex. Biomechanical studies revealed important roles of both the plantar plane and collateral ligaments. Since part of the plantar plate is attached to the deep transverse metatarsal ligament (DTML), we hypothesized that the transection of the DTML in the intermetatarsal space may substantially reduce the MTPJ stability. METHODS: The second, third, and fourth MTPJ stabilities of 6 fresh-frozen human cadaveric foot specimens were measured under load control. Both dorsiflexion and dorsal subluxation conditions were tested. After the intact condition was assessed, the DTML was sequentially transected such that each MTPJ had a unilateral and then a bilateral DTML transection. Stiffness data were calculated using the loading range in each test condition. Paired Student t tests were performed to test for statistical significance (P value less than .05). RESULTS: In intact specimens, the mean stiffness with dorsiflexion of the second, third, and fourth toes was 0.52 ± 0.15 N/deg. When the DTML was operatively transected on one side, the dorsiflexion stiffness significantly decreased 17.3% to an average of 0.43 ± 1.00 N/deg (P < .001). Subsequent transection of the DTML on the other side of each joint resulted in a further significant decrease of 5.8% to an average of 0.40 ± 0.08 N/deg (P < .001). The mean stiffness with dorsal subluxation of the intact second, third, and fourth toes was 3.55 ± 0.66 N/mm. When the DTML was operatively transected on one side, the dorsal subluxation stiffness significantly decreased 16.1% to an average of 2.98 ± 0.64 N/mm (P < .001). Subsequent transection of the DTML on the other side of each joint resulted in a further significance decrease of 7.6% to an average of 2.71 ± 0.48 N/mm (P = .016). CONCLUSION: The DTML has a significant role in maintaining lesser MTPJ ligament stability. Both unilateral and bilateral DTML transections caused substantial instability of the lesser MTPJ. CLINICAL RELEVANCE: The DTML is part of the natural static restraint to dorsiflexion or dorsal subluxation of the lesser MTPJ. Operative transection, injury, or degeneration of this ligament may predispose the adjacent MTPJ to instability.

Radiographic evaluation of bone adaptation adjacent to percutaneous osseointegrated prostheses in a sheep model.

BACKGROUND: Percutaneous osseointegrated prostheses (POPs) are being investigated as an alternative to conventional socket suspension and require a radiographic followup in translational studies to confirm that design objectives are being met. QUESTIONS/PURPOSES: In this 12-month animal study, we determined (1) radiographic signs of osseointegration and (2) radiographic signs of periprosthetic bone hypertrophy and resorption (adaptation) and (3) confirmed them with the histologic evidence of host bone osseointegration and adaptation around a novel, distally porous-coated titanium POP with a collar. METHODS: A POP device was designed to fit the right metacarpal bone of sheep. Amputation and implantation surgeries (n = 14) were performed, and plane-film radiographs were collected quarterly for 12 months. Radiographs were assessed for osseointegration (fixation) and bone adaptation (resorption and hypertrophy). The cortical wall and medullary canal widths were used to compute the cortical index and expressed as a percentage. Based on the cortical index changes and histologic evaluations, bone adaptation was quantified. RESULTS: Radiographic data showed signs of osseointegration including those with incomplete seating against the collar attachment. Cortical index data indicated distal cortical wall thinning if the collar was not seated distally. When implants were bound proximally, bone resorbed distally and the diaphyseal cortex hypertrophied. CONCLUSIONS: Histopathologic evidence and cortical index measurements confirmed the radiographic indications of adaptation and osseointegration. Distal bone loading, through collar attachment and porous coating, limited the distal bone resorption. CLINICAL RELEVANCE: Serial radiographic studies, in either animal models or preclinical trials for new POP devices, will help to determine which designs are likely to be safe over time and avoid implant failures.

Role of plantar plate and surgical reconstruction techniques on static stability of lesser metatarsophalangeal joints: a biomechanical study.

BACKGROUND: Disruption of the plantar plate of the lesser metatarsophalangeal (MTP) joints leads to significant instability. Despite the fact that plantar plate disorders are common, the best mode of treatment remains controversial with operative treatments having variable and somewhat unpredictable clinical outcomes. METHODS: Lesser MTP joints from the second, third, and fourth toes from fresh-frozen cadaver feet were biomechanically tested: (1) intact, (2) with the plantar plate disrupted, and (3) following a Weil osteotomy, a flexor-to-extensor tendon transfer, or a Weil osteotomy with a subsequent flexor-to-extensor tendon transfer with testing in superior subluxation, dorsiflexion, and plantarflexion. RESULTS: The plantar plate significantly contributed to stabilizing the sagittal plane of the lesser MTP joints. The flexor-to-extensor tendon transfer significantly stabilized the disrupted lesser MTP joints in both superior subluxation and in dorsiflexion. The flexor-to-extensor tendon transfer following a Weil osteotomy also significantly stabilized the disrupted lesser MTP joints in both superior subluxation and in dorsiflexion. CONCLUSIONS: In this cadaver-based experiment, disruption of the plantar plate of the lesser MTP joints led to significant instability. After plantar plate disruption, the Weil osteotomy left the joint unstable. The flexor-to-extensor tendon transfer by itself increased the stability of the joint in dorsiflexion, but combined with a Weil osteotomy restored near intact stability against superior subluxation and dorsiflexion forces. CLINICAL RELEVANCE: Surgeons using the Weil osteotomy for plantar plate deficient MTP joints may consider adding a flexor tendon transfer to the procedure. Techniques to repair the torn plantar plate directly are needed.

Minimally invasive approach for the treatment of non-isolated congenital vertical talus.

BACKGROUND: Traditional extensive soft-tissue release for the treatment of congenital vertical talus is associated with a myriad of complications. A minimally invasive approach has recently been introduced with good short-term results in patients with isolated vertical talus. The purpose of the present study was to evaluate the effectiveness of this approach for the treatment of rigid vertical talus associated with neuromuscular and/or genetic syndromes. METHODS: Fifteen consecutive patients (twenty-five feet) with non-isolated congenital vertical talus were retrospectively reviewed at a minimum of two years following treatment with serial casting followed by limited surgery. The surgery consisted of percutaneous Achilles tenotomy in all feet and either pin fixation of the talonavicular joint through a small medial incision to ensure joint reduction and accurate pin placement (five feet) or selective capsulotomies of the talonavicular joint and the anterior aspect of the subtalar joint (twenty feet). Patients were evaluated clinically and radiographically at the time of presentation, immediately postoperatively, and at the time of the latest follow-up. Radiographic data at the time of the latest follow-up were compared with age-matched normative values. RESULTS: Initial correction was obtained in all cases. The mean number of casts required was five. Mean ankle dorsiflexion was 22° and mean plantar flexion was 25° at the time of the latest follow-up. Recurrence was noted in three patients (five feet), all of whom had had initial subluxation of the calcaneocuboid joint. All radiographic parameters measured at the time of the latest follow-up had improved significantly (p < 0.0001) compared with the values before treatment, and the mean values of the measured angles did not differ significantly from age-matched normal values. CONCLUSIONS: Serial manipulation and casting followed by limited surgery, consisting of percutaneous tenotomy of the Achilles tendon and a small medial incision to either palpate the talonavicular joint or perform capsulotomies of the talonavicular joint and the anterior aspect of the subtalar joint to ensure accurate reduction and pin fixation, result in excellent short-term correction of the deformity while preserving subtalar and ankle motion in patients with rigid congenital vertical talus associated with neuromuscular and/or genetic syndromes.