Limb Fractures Treated With the Novel Plate Osteosynthesis Application Technique: Second to Minimally Invasive Plates osteosynthesis.

BACKGROUND: The main aim of this article was to propose a new concept of minimally invasive surgery for treating limb fractures, named as second to minimally invasive plates osteosynthesis (STMIPO). METHODS: We have described the STMIPO technique in a step-wise and standardized manner based on our findings from a study involving six patients treated at our institution. All patients with fracture achieved satisfactory outcomes. RESULTS: Ours clinical trials have shown that the STMIPO technique can be successfully applied in various limb fractures, including fibula fractures, tibial fractures, femur fractures, humerus fractures, ulna fractures, and radius fractures. All fracture patients achieved satisfactory outcomes. CONCLUSION: As a new minimally invasive technology, the STMIPO technique can serve as an alternative solution for fractures that are difficult to reduce with minimally invasive plates osteosynthesis (MIPO).

Refracture Following Operative Treatment of Pediatric Both Bone Forearm Fractures.

INTRODUCTION: Both bone forearm fractures are common injuries in children. Most can be treated with reduction and casting. Those that fail nonoperative management can be treated with a plate or intramedullary fixation; however, refracture remains a problem. The goal of this study is to evaluate the refracture rate in both bone forearm fractures based on the mode of fixation. METHODS: Institutional board review approval was obtained. A retrospective chart review from 2010 to 2021 at a single tertiary care institution was conducted for all operative patients <18 years who sustained a both bone forearm fracture. Groups were stratified based on initial operative fixation type: both bones fixated using nails, 1 bone fixated with a nail; both bones plated, and 1 bone plated. Further review was conducted to identify refractures following initial operative treatment. Statistical analyses were conducted using the χ 2 test of independence and Fisher's exact test. RESULTS: In all, 402 operatively treated both bone forearm fracture patients were identified. Two hundred fifty-six of these patients underwent intramedullary fixation (average age 10.3y/o), while 146 patients received plate fixation (average age 13.8y/o). Fracture location was similar across the nailing and plating cohorts, most often occurring in the mid-shaft region. Patients aged ≤10 years refractured at a significantly higher rate than patients aged >10 years across all operative fixation cohorts (12.5% vs. 2.5%, P <0.001). Among the 256 patients who underwent intramedullary fixation, 61.3% had both bones treated (n=157/256), whereas 38.7% received single bone fixation (n=99/256). Of the 146 plate fixations, 84.4% had both bones fixed (n=123/146), and only 15.8% were treated with single bone fixation (n=23/146). In the intramedullary group, 15 patients sustained refractures, 11 of whom were treated with single bone fixation (11.1%, n=11/99) versus 4 with both both fixation (2.5%, n=4/157). Among the plating group, 7 patients sustained refractures, 6 with both bone fixation (4.9%, n=6/123) and 1 in single bone fixation (4.3%, n=1/23). Refractures were found to be significantly more prevalent among patients treated with single bone compared with both bone intramedullary nail fixation (11.1% vs. 2.5%, P =0.006). By fixated bone, single bone ulna fixations had a higher refracture rate compared with both bone fixations (12.1% vs. 3.6%, P =0.003). CONCLUSION: The overall refracture rate following operative treatment of both bone fractures is 5.5% and is similar between intramedullary and plate fixations. Overall, patients ≤10 years of age had a higher rate of refracture. Among single bone fixations, higher refracture was seen with intramedullary fixations, and when the radius was treated nonoperatively. Surgeons may be able to reduce the refracture rate by performing intramedullary fixation of both bones instead of only one bone. Effective postoperative counseling among younger patients may also decrease refracture rates.

Treatment of an Ulnar Fracture Bone Defect Using Heterotopic Bone Autograft: A Case Report.

CASE: Autologous bone grafting has wide applications for the treatment of bony defects. Generally, cancellous or corticocancellous bone grafts are used depending on the characteristics and size of the bony defect and wound bed. The use of heterotopic bone as a potential source of bone graft has not been widely reported. We present a 56-year-old right-hand-dominant male victim of dog mauling who sustained a right ulnar fracture with a 5-cm bony defect, treated with the use of heterotopic bone autograft. CONCLUSION: Heterotopic bone can be successfully used as an autograft in the treatment of bony defects.

Anteroposterior Cannulated Screw Fixation of Coronoid Fractures in Terrible Triad Injuries: A Simple Syringe-guided Technique.

OBJECTIVE: The fixation of the coronoid fractures in terrible triad injuries is quite challenging. In this study, we introduce a minimally invasive technique using a syringe as a guide for insertion of the cannulated screw in an anterior to posterior fashion to fix the coronoid fracture in patients with terrible triad injuries. METHODS: In this retrospective study, clinical data of patients suffering from terrible triad injuries between 2012 and 2019 were analyzed. Fifteen patients with an average age of 38.2 years old (21-56 years) were enrolled in this study, of which 12 were males and three were females. The Regan-Morrey type II and type III coronoid fractures in these patients were treated with cannulated screws, inserted anteriorly using a 1 mL syringe as a guide. Outcome measures included pain, range of motion, stability and daily function using Mayo Elbow Performance scores (MEPs). The anteroposterior and lateral radiographs were used for evaluating a healing fracture. RESULTS: After a mean follow up of 44.2 months (range 13-80), the mean elbow flexion was 128.2°, extension was 12.3°, forearm pronation was 74.6° and supination was 73.6°. A concentric reduction was maintained without severe pain, stiffness, and radiographic evidence of instability in all patients during the follow-up period. The mean MEPs was 89.7 points. CONCLUSION: The anteroposterior cannulated screw fixation via simple syringe guide is a minimally invasive and safe option for surgical treatment of coronoid fractures in terrible triad injuries.

Single Modified Posterior Approach through the Space of the Proximal Radioulnar Joint for Terrible Triad Injury: A Comparative Study.

OBJECTIVE: In order to reduce surgical scars and the risk of neurovascular injury for the treatment of terrible triad injuries of the elbow (TTI), minimally invasive and better therapeutic effect approaches are being explored to replace the conventional combined lateral and medial approach (CLMA). This study was performed to compare the clinical effect and security of the modified posterior approach (MPA) through the space of the proximal radioulnar joint vs the CLMA for treatment of TTI. METHODS: This study retrospectively analyzed 76 patients treated for TTI from January 2009 to December 2020 (MPA: n = 44; CLMA: n = 32). Treatment involved plate and screw fixation or Steinmann pin fixation for the radial head and ulnar coronoid process fractures. Surgeons only sutured the lateral ligament because the medial collateral ligament was usually integrated in the TTI. The continuous variables were compared by the independent Student t-test and the categorical variables by the χ2 -test or Fisher's exact test. RESULTS: Both groups of patients attained a satisfactory MEPS after the operation. The MEPS (MPA: 96.82 ± 6.04 vs CLMA: 96.56 ± 5.51) was not significantly different between the two groups (p > 0.05). However, the MPA resulted in better elbow flexion and extension (MPA: 123.98 ± 10.09 vs CLMA: 117.66 ± 8.29), better forearm rotation function (MPA: 173.41 ± 6.81 vs CLMA: 120.00 ± 12.18), and less intraoperative hemoglobin (MPA: 9.34 ± 5.64 vs CLMA: 16.5 ± 8.75) and red cell volume loss (MPA: 3.09 ± 2.20 vs CLMA: 6.70 ± 2.97) (All p < 0.05). Although the CLMA had a shorter surgery time (MPA: 171.73 ± 80.68 vs CLMA: 130.16 ± 71.50) (p < 0.05), it had a higher risk of neurologic damage (MPA: 0 vs CLMA: 4) (p < 0.05). Four patients developed forearm or hand numbness after the CLMA, but no patients developed numbness after the MPA. All 76 patients were followed up for 15 months postoperatively. CONCLUSION: The MPA through the space of the proximal radioulnar joint has more prominent advantages than the CLMA for TTI, including single scar, clear exposure, good fixation, lower risk of neurovascular injury, and better elbow joint motion. It is a safe and effective surgical approach that is worthy of clinical promotion.

Retrospective analysis: risk factors predicting failure of closed reduction in pediatric diaphyseal forearm fractures treated with elastic stable intramedullary nails (ESINs).

LEVEL OF EVIDENCE: Level IV.

Re-fractures of the paediatric radius and/or ulna: A systematic review.

BACKGROUND: Fractures of the radius and/or ulna are one of the most common injuries in children. Evidence identifying risk factors for refracture, however, has not been summarised in a systematic review. Guidance for counselling patients and parents to minimise the risk of refracture is limited. The aims of this study are to 1) to determine if casting time 6 weeks or less is a risk factor for refracture after paediatric radius and/or ulna fractures, 2) to identify other risk factors for refracture after paediatric radius and/or ulna fractures and 3) to develop more accurate guidelines for counselling parents after a radius and/or ulna fracture in their child. METHODS: A thorough search was performed in accordance with the Joanna Briggs Institute (JBI) guidelines for systematic review. JBI Critical Appraisal checklists were used for risk of bias assessment. RESULTS: Diaphyseal both-bone fractures treated non-surgically should be casted for longer than 6 weeks. Surgically treated patients can be casted for less than 6 weeks. Diaphyseal and greenstick fractures have a higher risk of refracture. Residual angulation and incomplete healing in greenstick fractures may lead to a higher risk of refracture. Gender does not affect refracture risk. Falls, use of wheeled vehicles, playground activities and trampolining confer high-risk of refracture. Refracture risk is greatest up to 9 months from initial fracture. CONCLUSION: Further case-controlled studies with sub-group analysis are required to further investigate risk factors for refracture after radius and/or ulna fractures in children.

Tips and tricks to achieve osteotomy healing and prevent refracture after ulnar shortening osteotomy.

BACKGROUND: Parallel osteotomy is essential for favorable osteotomy reduction and healing and technically challenging during diaphyseal ulnar shortening osteotomy (USO). This study aimed to evaluate the advantages of guided osteotomy for parallel osteotomy and reduction osteotomies, healing over freehand osteotomy. It also aimed to identify surgical factors affecting healing after diaphyseal USO. METHODS: Between June 2005 and March 2016, 136 wrists that had undergone diaphyseal USO for ulnar impaction syndrome (UIS) were evaluated. The wrists were divided into two groups according to the osteotomy technique (group 1: freehand osteotomy, 74 wrists; group 2: guided osteotomy, 62 wrists). The osteotomy reduction gap and time to osteotomy healing (union and consolidation) were compared between the groups. A multiple regression test was performed to identify the surgical factors affecting healing. The cut-off length of the reduction gap to achieve osteotomy union on time and the cut-off period to decide the failure of complete consolidation were statistically calculated. RESULTS: The baseline characteristics did not differ between the two groups. The osteotomy reduction gap and time to osteotomy union, and complete consolidation were shorter in group 2 than in group 1 (p = 0.002, < 0.001, 0.002). The osteotomy reduction gap was a critical surgical factor affecting both time to osteotomy union and complete consolidation (p < 0.001, < 0.001). The use of a dynamic compression plate affected only the time to complete consolidation (p < 0.001). The cut-off length of the osteotomy reduction gap to achieve osteotomy union on time was 0.85 mm. The cut-off period to decide the failure of complete consolidation was 23.5 months after osteotomy. CONCLUSIONS: The minimal osteotomy reduction gap was the most important for timely osteotomy healing in the healthy ulna, and guided osteotomy was beneficial for reducing the osteotomy reduction gap.

Refracture after plate removal following ulnar shortening osteotomy for ulnar impaction syndrome - a retrospective case-control study.

LEVEL OF EVIDENCE: Level III, case-control study.

Greenstick fracture of the ulnar shaft following physical therapy in an adult: A case report.

RATIONALE: Greenstick fractures most commonly occur in the pediatric population, especially in those under 10 years of age. Greenstick fractures are "extremely" rare in adults. This report presents the case of a greenstick fracture of the ulnar shaft in an adult following physical therapy for a radial neck fracture and ulnar shaft fracture post-internal fixation. Greenstick fracture can occur during physical therapy near the drill holes created during surgery. PATIENT CONCERNS: A 23-year-old man without any past medical history had sustained a greenstick fracture of the ulnar shaft after rehabilitation for a left radial and ulnar fracture that had been previously treated with internal fixation. DIAGNOSES: Five months after removal of the implants, the patient complained of left elbow tenderness and a "breaking" sound that occurred during physical therapy. The results of a subsequent X-ray revealed a greenstick fracture of the left ulnar shaft. INTERVENTIONS: Splinting of the fracture. OUTCOMES: After 2 months of splint fixation, the pain and range of motion in the affected arm were improved, and sequential X-rays showed callus formation and increased density of the ulnar shaft. LESSONS: Greenstick fractures occur not only in children but also in adults in specific circumstances. The cortex of long bones may be further weakened by drill holes created during surgery, and fractures may occur during physical therapy. During treatment, physicians, and therapists should pay more attention to the patient who has undergone implant removal to avoid greenstick fractures, especially in the locations near drill holes.

Ulnar stress reaction in an axillary crutch user.

Ulnar stress fractures have been reported in athletes performing repetitive, high-impact activities, such as baseball pitchers and gymnasts. Crutch-assisted walking also results in cyclical forearm loading. We report the first case of ulnar stress reaction due to axillary crutch use. A 23-year-old right-handed woman experienced right forearm pain and imaging confirmed a right ulnar stress injury. The patient was also found to have mild hypercortisolism, low bone mass and vitamin D deficiency. Crutches were discontinued and physical therapy to normalise weight bearing through the left leg was prescribed. The patient's right forearm symptoms resolved and she was started on oral vitamin D supplementation. Axillary crutch use may result in ulnar stress injury, particularly in vulnerable populations. The addition of an upper extremity injury to someone with impaired mobility may compound disability. As such, clinicians should be aware of the clinical presentation of ulnar stress fractures in the long-term axillary crutch user.

Aluminium Splint Incorporated Fibreglass Cast Preserves Limb Function in Bovines with Olecranon Fracture.

OBJECTIVE: Olecranon process fractures are rare in bovines. The aim of the study was to put on record satisfactory limb usage in cattle and buffaloes suffering from olecranon fractures and treated conservatively, primarily for carpal contracture or to prevent it, using aluminum splints incorporated within a fiberglass cast along with stall confinement. STUDY DESIGN: This one year study included 19 olecranon fractures in bovines (15 buffaloes and 4 cattle). Out of 19, 12 bovines (9 buffaloes and 3 cattle) were treated primarily to manage the associated carpal contracture, using external coaptation of aluminium splints incorporated within a fiberglass cast for 6 to 8 weeks. The owners of the remaining 7 bovines (6 buffaloes and 1 bullock) were only advised to keep their animal in stall-confinement, due to various reasons. RESULTS: Slipping and falling on hard surfaces was the primary aetiology of olecranon fractures (17/19). Most of the fractures (14/19) were presented more than 10 days after a traumatic event, with a mean duration of 24.0 ± 26.6 days. On follow up, all the treated bovines showed satisfactory limb usage whereas all stall-confined buffaloes showed no improvement. CONCLUSION: Slipping and falling on hard surfaces is a common cause of olecranon fracture in bovines. Olecranon fractures associated carpal contracture can be successfully treated/prevented by applying full limb cast (if possible including elbow) along with aluminum splints leading to satisfactory limb usage in bovines. Further it is concluded that stall confinement alone is insufficient to prevent limb contracture (which usually develops with olecranon fracture in bovines) leading to permanent non-weight bearing disability.

Association between bone mineral density and ulnar styloid fracture in older Japanese adults with low-energy distal radius fracture.

We investigated the association of the ulnar styloid fracture (USF) with the bone mineral status and fractured radial displacement in elderly patients. The presence of USF correlates with decreased BMD and severe displacement of the radius. These findings are helpful in treating osteoporosis to prevent subsequent fragility fracture. PURPOSE: The pathogenesis of ulnar styloid fracture (USF), which often occurs with distal radius fracture (DRF), is unclear. This study aimed to investigate whether USF concomitant with low-energy DRF was associated with the bone mineral status and the degree of radiographically observed pretreatment radius displacement in Japanese adults above 50 years of age. METHODS: The study subjects were 45 (44 female, 1 male) consecutive patients aged > 50 years with DRF caused by falls from June 2015 to May 2016. Fractures due to high-energy injuries were excluded. Patients were divided into two groups according to the presence or absence of USF. Radius displacement was assessed on anteroposterior and lateral radiographs by measuring ulnar variance, radial inclination, and volar tilt at initial examination before manual reduction of the bone. Bone mineral density (BMD) of the lumbar spine, femoral neck, and distal radius was also measured by dual-energy X-ray absorptiometry within 1 week of injury. RESULTS: Significant differences in the BMD values of femoral neck, ulnar variance, radial inclination, and volar tilt were found between patients with USF and those without USF (all comparisons, p < 0.05). Logistic regression analysis of all subject data identified that volar tilt was significantly associated with the presence of USF (p = 0.048). CONCLUSIONS: The presence of USF in low-energy DRF correlates with the decreased BMD of femoral neck and severe displacement of radius in elderly patients. These findings are helpful for the treatment of osteoporosis to prevent subsequent fragility fracture.

Olecranon Fracture through Persistent Olecranon Apophysis in a 21-Year-Old Male: A Case Report and Systematic Review of the Literature.

Traumatic fractures involving an ununited olecranon apophysis in adults have been rarely documented in the literature. We present the case of a 21-year-old male wrestler with an elbow injury after a fall. Imaging revealed an acute fracture of the olecranon with sclerotic rounded edges indicating an injury through a persistent olecranon apophysis. Open reduction and internal fixation was performed with plate fixation and bone grafting with radiographic and clinical healing at 6 weeks. Review of the literature revealed 5 case reports showing high rates of non-union with tension band constructs while plate and screw fixation had no incidence of nonunion. Fractures through an ununited olecranon apophysis are successfully treated with plate and screw fixation with bone grafting.

Association between hand-grip strength and site-specific risks of major osteoporotic fracture: Results from the Japanese Population-based Osteoporosis Cohort Study.

OBJECTIVES: To investigate the association between hand-grip strength and site-specific risks of major osteoporotic fracture. STUDY DESIGN: Prospective cohort study. MAIN OUTCOME: Associations between low hand-grip strength and increased risk of fracture at the distal forearm, vertebrae, and hip. MEASURES: We enrolled 1342 postmenopausal women aged 50 years or more into baseline and follow-up surveys of the Japanese Population-based Osteoporosis Cohort Study in 1996, 1999, 2002, or 2006. Fracture events were ascertained by follow-up surveys until 2011 or 2012. The Cox proportional hazards model was used to estimate hazard ratios (HRs) of hand-grip strength on fracture event. RESULTS: During a median follow-up of 15.2 years, 162 women sustained at least one osteoporotic fracture and 135 of these women sustained at least one major osteoporotic fracture, the larger group including 65, 38, 35, and 8 women with fractures of the distal forearm, vertebrae, hip, and proximal humerus, respectively. In the crude models, the associations between low hand-grip strength and increased risk of fracture at the distal forearm, vertebrae, and hip were significant; the HRs (95% confidence interval) of the lowest tertile of hand-grip strength were 2.02 (1.10-3.71), 11.35 (4.07-31.63), and 4.72 (1.79-12.47), respectively. Age adjustment attenuated the significance of hip fracture risk, and adjusting for bone mineral density attenuated the significance of distal forearm fracture risk. After additional adjustment for body mass index, history of diabetes mellitus, and calcium intake, the HR for vertebral fracture risk was 4.55 (1.56-13.27). When limiting the follow-up period to 5 and 10 years, low hand-grip strength was associated with an increased risk of distal forearm fracture independently of the aforementioned covariates; the HRs were 4.22 (1.12-15.95) and 2.52 (1.03-6.17), respectively. CONCLUSIONS: Low hand-grip strength is specifically associated with the risk of distal forearm fractures within 10 years and clinical vertebral fractures within 15 years or more in Japanese postmenopausal women.

Incidence patterns of traumatic upper limb fractures in children and adolescents: Data from medical university-affiliated hospitals in Chongqing, China.

China's child population ranked second in the world. However, data on the overall patterns and epidemiologic trends of TULFs among children and adolescents in Chongqing, China are scarce. With development of urbanization, motorization, building industry, the incidence patterns of traumatic upper limb fractures in children and adolescents might be about to change. To investigate the incidence patterns of traumatic upper limb fractures in children and adolescents (≤18 years old) according to age (≤3 years old, 3-6 years old, 6-12 years old, and 12-18 years old), gender, time, and etiology groups in Chongqing, China, we retrospectively reviewed 1078 children and adolescents who had traumatic upper limb fractures and who came to our university-affiliated hospitals from 2001 to 2010. The patients were grouped into different age groups, genders, year of admission range groups, and aetiologies. We used Pearson chi-square tests and independent samples t tests to assess differences of the grouped data and continuous variables, respectively. This study enrolled 1078 patients (849 males, 229 females) aged 11.0 ±â€Š4.7 years old. The most common aetiologies and fracture sites of patients were low falls (705, 65.4%) and humerus (492, 45.6%). A total of 146 (13.5%) patients suffered a nerve injury, 94 (8.7%) patients sustained associated injuries, and 106 (9.8%) patients sustained complications. The proportion of injuries due to motor vehicle collisions increased with increasing age and year of admission. Female patients presented with significantly higher proportion of injuries due to motor vehicle collisions and significantly lower proportion of injuries due to hit by others. The proportion decreased from 63.2% to 33.3% in humeral fracture, increased from 8.8% to 35.5% in radius fracture, increased from 7.4% to 28.9% in ulna fracture with increasing age. Female patients presented with significantly higher proportion of humeral fracture, clavicle fracture and significantly lower proportion of radius fracture, ulna fracture, and hand fracture. Low falls and humerus fractures were the most common aetiologies and fracture sites. The pattern of traumatic upper limb fractures has specific age, gender, time, and etiology differences.

Hoverboard injuries in children and adolescents: results of a multicenter study.

With the increasing popularity of hoverboards in recent years, multiple centers have noted associated orthopaedic injuries of riders. We report the results of a multi-center study regarding hoverboard injuries in children and adolescents. who presented with extremity fractures while riding hoverboards to 12 paediatric orthopaedic centers during a 2-month period were included in the study. Circumstances of the injury, location, severity, associated injuries, and the required treatment were recorded and analysed using descriptive analysis to report the most common injuries. Between-group differences in injury location were examined using chi-squared statistics among (1) children versus adolescents and (2) males versus females. Seventy-eight patients (M/F ratio: 1.8) with average age of 11 ± 2.4 years were included in the study. Of the 78 documented injuries, upper extremity fractures were the most common (84.6%) and the most frequent fracture location overall was at the distal radius and ulna (52.6%), while ankle fractures comprised most of the lower extremity fractures (66.6%). Majority of the distal radius fractures (58.3%) and ankle fractures (62.5%) were treated with immobilization only. Seventeen displaced distal radius fractures and three displaced ankle fractures were treated with closed reduction in the majority of cases (94.1% versus 66.7%, respectively). The distal radius and ulna are the most common fracture location. Use of appropriate protective gear such as wrist guards, as well as adult supervision, may help mitigate the injuries associated with the use of this device; however, further studies are necessary to demonstrate the real effectiveness of these preventions.

Spatiotemporal Distribution of Linear Microcracks and Diffuse Microdamage Following Daily Bouts of Fatigue Loading of Rat Ulnae.

Microdamage accumulation contributes to impaired skeletal mechanical integrity. The bone can remove microdamage by initiating targeted bone remodeling. However, the spatiotemporal characteristics of microdamage initiation and propagation and their relationship with bone remodeling in response to fatigue loading, especially for more physiologically relevant daily bouts of compressive loading, remain poorly understood. The right forelimbs of 24 rats were cyclically loaded with a ramp waveform for 1,500 cycles/day, and contralateral ulnae were not loaded as the controls. The rats were divided into four equal groups and loaded for 1, 4, 7, and 10 days, respectively. We demonstrated that linear microcracking accumulation exhibited a non-linear time-varying process within 10 days of loading with peaked microcrack density at Day 7. Disrupted canaliculi surrounding linear microcracks showed high similarity with the temporal changes of linear microcracking accumulation. Observable intracortical resorption regions were found on Day 10. We found more linear microcracks accumulated in the tensile cortex, but longer cracks were observed in the compressive sides. Increased accumulation of diffuse microdamage was observed from Day 4, but no obvious peak was observed within the 10-day loading period. Diffuse damage first initiated in the compressive cortices but extended to tension from Day 7. The diffuse damage exhibited no impacts on the surrounding osteocyte integrity. Together, our findings revealed a time-dependent, bone remodeling-mediated varying process of linear microcracking accumulation following daily bouts of fatigue loading (with observable peak at Day 7 under our loading regime). Our study also identified distinct spatial accumulation of linear and diffuse microdamage in rat ulnae with tensile and compressive strains. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2112-2121, 2019.