Heterotopic ossification, osteolysis and implant failure following cervical total disc replacement with the M6-C™ artificial disc.

INTRODUCTION: A recent study reported a 34% mid-term revision rate after M6-C™ cervical total disc replacement (CTDR) for wear-related osteolysis. Here, we aim to investigate the prevalence, risk factors, and radiographic characteristics of periprosthetic bony changes and implant failure of the M6-C™ artificial disc. METHODS: We retrospectively analysed radiographic (conventional X-ray, CT scan) and clinical outcomes (EQ-5D-5L, Neck Disability Index (NDI), and Visual Analog Scale (VAS) for neck and arm pain) data collected during routine follow-up of patients who underwent CTDR with the M6-C™ between 2011 and 2015. RESULTS: In total, 85 patients underwent CTDR with the M6-C™. Follow-up data were available for 43 patients (54% female, mean age 44 years) with 50 implants and a mean follow-up of 8.1 years (6.5-11 years). Implant failure with the presence of severe osteolysis was identified in 5 (12%) patients who were all male (p = 0.016) and implanted at the C5/6 level (p = 0.11). All failed implants required revision surgery. The overall prevalence of osteolysis was 44% (22/50 implants) and 34% (17/50 implants) for significant heterotopic ossification. Patients with high-grade osteolysis showed higher VAS arm pain (p = 0.05) and lower EQ-5D-VAS health VAS (p = 0.03). CONCLUSION: We report a lower reoperation rate for failed M6-C™ implants than previously published, but confirmed that osteolysis and heterotopic ossification are common following CTDR with the M6-C™ and may be asymptomatic. Therefore, we strongly recommend ongoing clinical and radiographic monitoring after CTDR with the M6-C™, particularly for male patients implanted at the C5/6 level.

Incidence and Risk Factors of Heterotopic Ossification in the Knee After Reamed Tibial Nailing.

INTRODUCTION: Heterotopic ossification (HO) in the knee after tibial intramedullary nailing (IMN) has yet to be thoroughly investigated. Our aim was to assess frequency and associated factors for HO in the knee after tibial IMN. METHODS: This is a retrospective review at a single level 1 urban trauma center of 213 patients who underwent reamed tibial IMN. Plain radiographs were reviewed postoperatively and on final follow-up (≥6 weeks). Chart review was performed for surgical approach (suprapatellar versus infrapatellar), demographics, injury characteristics, and clinical follow-up. The primary outcome was frequency of HO. RESULTS: HO on final follow-up (mean: 41.43 weeks) was recorded in 15% cases. Postsurgical retroinfrapatellar reaming debris (odds ratio [OR], 4.73), Injury Severity Score (OR, 1.05), intensive care unit admission (OR, 2.89), chest injury (OR, 3.4), and ipsilateral retrograde femoral IMN (OR, 5.08) showed a notable association with HO development. No association was observed in HO formation between surgical approach, knee pain, or range-of-motion deficits. DISCUSSION: Radiographic evidence of HO in the knee after reamed tibial IMN is not uncommon and is associated with retained reaming debris, Injury Severity Score, chest injury, intensive care unit admission, and ipsilateral retrograde femoral nailing. No differences were noted in HO formation between approaches. HO was not associated with knee pain or range-of-motion deficits.

Regional distribution prevalence of heterotopic ossification in the elbow joint: a 3D study of patients after surgery for traumatic elbow injury.

BACKGROUND: Heterotopic ossification (HO) is a common complication after elbow fracture surgery and can lead to severe upper extremity disability. The radiographic localization of postoperative HO has been reported previously. However, there is no literature examining the distribution of postoperative HO at the three-dimensional (3D) level. This study aimed to investigate 1) the distribution characteristics of postoperative HO and 2) the possible risk factors affecting the severity of postoperative HO at a 3D level. METHODS: A retrospective review was conducted of patients who presented to our institution with HO secondary to elbow fracture between 13 January 2020 and 16 February 2023. Computed tomography scans of 56 elbows before elbow release surgery were reconstructed in 3D. HO was identified using density thresholds combined with manual identification and segmentation. The elbow joint and HO were divided into six regions according to three planes: the transepicondylar plane, the lateral ridge of the trochlear plane, and the radiocapitellar joint and coronoid facet plane. The differences in the volume of regional HO associated with different initial injuries were analyzed. RESULTS: Postoperative HO was predominantly present in the medial aspect of the capsule in 52 patients (93%), in the lateral aspect of the capsule in 45 patients (80%), in the medial supracondylar in 32 patients (57%), and in the lateral supracondylar, radial head, and ulnar region in the same number of 28 patients (50%). The median and interquartile range volume of total postoperative HO was 1683 (777-4894) mm3. The median and interquartile range volume of regional postoperative HO were: 584 (121-1454) mm3 at medial aspect of capsule, 207 (5-568) mm3 at lateral aspect of capsule, 25 (0-449) mm3 at medial supracondylar, 1 (0-288) at lateral supracondylar, 2 (0-478) at proximal radius and 7 (0-203) mm3 at the proximal ulna. In the subgroups with Injury Severity Score > or = 16, Gustilo-Anderson II, normal uric acid levels, elevated alkaline phosphatase, and body mass index > or = 24, the median HO volume exceeds that of the respective control groups. CONCLUSION: The medial aspect of the capsule was the area with the highest frequency and median volume of postoperative HO among all initial elbow injury types. Patients with higher Gustilo-Anderson grade, Injury Severity Score, alkaline phosphatase or Body Mass Index had higher median volume of postoperative HO.

Eagle jugular syndrome accompanied by de novo brainstem cavernous malformation: a case-based systematic review.

BACKGROUND: Eagle jugular syndrome (EJS), recently identified as a cause of cerebrovascular disease (CVD) due to venous obstruction by an elongated styloid process (SP), is reported here alongside a case of concurrent de novo cerebral cavernous malformation (CCM). This study aims to explore the potential causal relationship between EJS and de novo CCM through a comprehensive literature review. METHOD: Systematic literature reviews, spanning from 1995 to 2023, focused on EJS cases with definitive signs and symptoms and de novo CCM cases with detailed clinical characteristics. Data on the pathophysiology and clinical manifestations of EJS, as well as potential risk factors preceding de novo CCM, were collected to assess the relationship between the two conditions. RESULT: Among 14 patients from 11 articles on EJS, the most common presentation was increased intracranial hypertension (IIH), observed in 10 patients (71.4%), followed by dural sinus thrombosis in four patients (28.6%). In contrast, 30 patients from 28 articles were identified with de novo CCM, involving 37 lesions. In these cases, 13 patients developed CCM subsequent to developmental venous anomalies (43%), seven following dural arteriovenous fistula (dAVF) (23%), and two after sinus thrombosis (6%). In a specific case of de novo brainstem CCM, the development of an enlarged condylar emissary vein, indicative of venous congestion due to IJV compression by the elongated SP, was noted before the emergence of CCM. CONCLUSION: This study underscores that venous congestion, a primary result of symptomatic EJS, might lead to the development of de novo CCM. Thus, EJS could potentially be an indicator of CCM development. Further epidemiological and pathophysiological investigations focusing on venous circulation are necessary to clarify the causal relationship between EJS and CCM.

Prevalence, Timing, Locational Distribution, and Risk Factors for Heterotopic Ossification After Elbow Arthroscopy.

BACKGROUND: Arthroscopic techniques aim to reduce complications and accelerate recovery of the elbow after treatments for posttraumatic stiffness, arthritis diseases, lateral epicondylitis, ligament reconstruction, and elbow trauma. However, data on the true prevalence and characteristics of heterotopic ossification (HO) formation after elbow arthroscopy are limited. PURPOSE: To investigate the prevalence, timing, locational distribution, and risk factors of HO after elbow arthroscopy. STUDY DESIGN: Cohort study; Level of evidence, 4. METHODS: Data on 205 patients undergoing elbow arthroscopy by a single senior elbow surgeon at a single institution between May 2011 and January 2022 were retrospectively reviewed. The patients were evaluated at 2 weeks, 8 weeks, 6 months, and then annually after surgery or more frequently if HO developed, with a minimum of 1 year of postoperative follow-up. Postoperative anteroposterior and lateral elbow radiographs were taken at 2 weeks to rule out fracture and at 8 weeks to identify HO. The clinical outcomes were evaluated based on the pain visual analog scale; the shortened version of the Disabilities of the Arm, Shoulder and Hand score; Mayo Elbow Performance Score; and the Single Assessment Numeric Evaluation scores before and after surgery. Bivariate logistic regression analyses were used to determine factors affecting HO prevalence. RESULTS: Thirteen (12 male, 1 female) of 205 (6.3%) patients developed HO, with 10 (76.9%) with HO that formed on the medial compartment of the elbow. Ten (76.9%) patients were diagnosed at 8 weeks after arthroscopic surgery, 1 (7.7%) at 6 months after surgery, and 2 (15.4%) at 12 months after surgery. HO was not found at 2 weeks after surgery in any patient. The mean follow-up time was 3.5 years (range, 1.0-11.8 years). Eleven asymptomatic patients were treated nonoperatively, and 2 symptomatic patients underwent HO excision arthroscopically or had a combination of open surgery and arthroscopy. Age was a protective factor for HO formation (odds ratio [OR], 0.953; 95% CI, 0.910-0.999; P = .047). The risk factors for HO formation were tourniquet time (OR, 1.042; 95% CI, 1.019-1.065; P < .001) and surgical time (OR, 1.026; 95% CI, 1.011-1.041; P < .001). CONCLUSION: Among 205 patients who underwent elbow arthroscopy, HO was a minor complication of elbow arthroscopy, with a prevalence rate of 6.3%, and was usually located on the medial compartment of the elbow. Although the presence of HO may not affect the clinical outcomes in most patients, it should be carefully monitored for a minimum of 8 weeks postoperatively. Younger age, longer tourniquet time, and longer surgical time contributed to HO formation after elbow arthroscopy.

Chemoprophylaxis for heterotopic ossification following hip arthroscopy: A systematic review.

INTRODUCTION: Heterotopic ossification (HO) is a known complication diagnosed following hip arthroscopy. PURPOSE/HYPOTHESIS: This study sought to review the current literature on chemoprophylaxis for HO following hip arthroscopy and to describe what agents and doses are being utilized. STUDY DESIGN: Systematic Review. METHODS: A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines on the use of chemoprophylactic medications for HO prevention following hip arthroscopy. Mechanical and radiation prophylaxis were not included in the current analysis. RESULTS: A total of 203 studies were identified, of which 15 were included with 6463 patients. There was one randomized control trial (RCT) and 4 additional comparative studies. The most commonly utilized chemoprophylactic agents were the following: naproxen (n â€‹= â€‹8), celecoxib (n â€‹= â€‹3), indomethacin (n â€‹= â€‹3), aspirin (n â€‹= â€‹1), etoricoxib (n â€‹= â€‹1), and etodolac (n â€‹= â€‹1), and non-specific non-steroidal anti-inflammatory drugs (NSAIDs) (n â€‹= â€‹1). Naproxen was either given at a dose of 500 â€‹mg once or twice daily for 2-4 weeks. RCTs and additional comparative studies showed significant HO prevention using chemoprophylactic agents following hip arthroscopy. CONCLUSIONS: HO is a known and common complication following hip arthroscopy. The current systematic review found significant heterogeneity across the literature with respect to specific chemoprophylactic agents and their dosing regimens aimed to reduce the incidence and severity of HO following hip arthroscopy. Additionally, this review demonstrates that most studies that utilize chemoprophylaxis use NSAIDs with successful reduction in the incidence of HO. LEVEL OF EVIDENCE: Level IV Evidence.

Association Between Tranexamic Acid Use and Heterotopic Ossification Prevalence After Elbow Trauma Surgery: A Propensity-Score-Matched Cohort Study.

BACKGROUND: Heterotopic ossification (HO) is a common complication of elbow trauma that can affect limb mobility. Inflammation is an initiating factor for HO formation. Tranexamic acid (TXA) can reduce the inflammatory response after orthopaedic surgery. However, evidence regarding the effectiveness of TXA use for HO prevention after elbow trauma surgery is lacking. METHODS: This retrospective observational propensity-score-matched (PSM) cohort study was conducted from July 1, 2019, to June 30, 2021, at the National Orthopedics Clinical Medical Center, Shanghai, People's Republic of China. A total of 640 patients who underwent surgery following elbow trauma were evaluated. The present study excluded patients with an age of <18 years; those with a history of elbow fracture; those with a central nervous system injury, spinal cord injury, burn injury, or destructive injury; and those who had been lost to follow-up. After 1:1 matching on the basis of sex, age, dominant arm, injury type, open injury, comminuted fracture, ipsilateral trauma, time from injury to surgery, and nonsteroidal anti-inflammatory drug use, the TXA group and the no-TXA group comprised 241 patients each. RESULTS: In the PSM population, the prevalence of HO was 8.71% in the TXA group and 16.18% in the no-TXA group (with rates of 2.07% and 5.80% for clinically important HO, respectively). Logistic regression analyses showed that TXA use was associated with a lower rate of HO (odds ratio [OR], 0.49; 95% CI, 0.28 to 0.86; p = 0.014) than no TXA use, as well as with a lower rate of clinically important HO (OR, 0.34; 95% CI, 0.11 to 0.91; p = 0.044). None of the baseline covariates significantly affected the relationship between TXA use and HO rate (p > 0.05 for all). Sensitivity analyses supported these findings. CONCLUSIONS: TXA prophylaxis may be an appropriate method for the prevention of HO following elbow trauma. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Heterotopic Ossification Formation in Military Beneficiaries Following Hip- and Pelvic-Level Amputations.

INTRODUCTION: Traumatic hip and pelvic level amputations are uncommon but devastating injuries and associated with numerous complications that can significantly affect quality of life for these patients. While heterotopic ossification (HO) formation has been reported at rates of up to 90% following traumatic, combat-related amputations, previous studies included few patients with more proximal hip and pelvic level amputations. MATERIALS AND METHODS: We conducted a retrospective review of the Military Health System medical record and identified patients with both traumatic and disease-related hip- and pelvic-level amputations performed between 2001 and 2017. We reviewed the most recent pelvis radiograph at least 3 months following amputation to determine bony resection level and the association between HO formation and reason for amputation (trauma versus disease related). RESULTS: Of 93 patients with post-amputation pelvis radiographs available, 66% (n = 61) had hip-level amputations and 34% (n = 32) had a hemipelvectomy. The median duration from the initial injury or surgery to the most recent radiograph was 393 days (interquartile range, 73-1,094). HO occurred in 75% of patients. Amputation secondary to trauma was a significant predictor of HO formation (χ2 = 24.58; P < .0001); however, there was no apparent relationship between the severity of HO and traumatic versus non-traumatic etiology (χ2 = 2.92; P = .09). CONCLUSIONS: Amputations at the hip were more common than pelvic-level amputations in this study population, and three-fourths of hip- and pelvic-level amputation patients had radiographic evidence of HO. The rate of HO formation following blast injuries and other trauma was significantly higher compared with patients with non-traumatic amputations.

Incidence of Heterotopic Ossification at 10 years After Cervical Disk Replacement: A Systematic Review and Meta-analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: This study aimed to assess the incidence of heterotopic ossification (HO) 10 years after cervical disk replacement (CDR). SUMMARY OF BACKGROUND DATA: HO is a common complication after CDR and may limit the range of motion of the artificial disk. As HO usually progresses slowly, a long-term follow-up is required to better understand its incidence. In recent years, the increasing number of original articles reporting 10-year outcomes gives us the opportunity to better understand the long-term incidence of HO. MATERIALS AND METHODS: We searched PubMed, Medline, Embase, and Cochrane Library databases to identify eligible studies. The incidence of HO was pooled, and subgroup analysis was performed. Meta-regression analyses were conducted to identify factors contributing to heterogeneity. RESULTS: Eleven studies with at least 10 years of follow-up comprising 1140 patients who underwent CDR were included. The pooled incidence of overall HO was 70% (95% CI, 60%-81%) at 10 years postoperatively, 60% (95% CI, 44%-75%) at five or six years postoperatively, and 50% (95% CI, 27%-72%) at one or two years postoperatively. The pooled incidence of severe HO (grade 3 or 4) was 37% (95% CI, 29%-45%), and mild HO (grade 1 to 2) was 30% (95% CI, 17%-44%) at 10 years of follow-up. Pooled range of motion decreased from 8.59° before surgery to 7.40° 10 years after surgery. Subgroup analysis showed that HO incidence differed according to the prosthesis type. The earlier publication was associated with a higher pooled incidence of severe HO in the meta-regression analysis. CONCLUSIONS: This is the first meta-analysis providing detailed information on the pooled 10-year incidence of HO after CDR. The incidence of HO seems to increase with the length of follow-up. LEVEL OF EVIDENCE: 3.

Is External Beam Radiation Therapy Really Associated With Low Rates of Heterotopic Ossification After Acetabular Surgery?

OBJECTIVES: Describe rate of postoperative heterotopic ossification (HO) after acetabular surgery in patients who received external beam radiation (XRT) as HO prophylaxis. DESIGN: Retrospective. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: Consecutive series of patients who presented to a single, level I, academic trauma center over a 10-year period (2008-2018) for surgical fixation of an acetabular fracture. Patients eligible for inclusion were those who underwent surgical fixation of an acetabular fracture through a posterior (Kocher-Langenbeck), combined anterior and posterior, or extensile exposure. Patients were excluded if an isolated anterior approach was performed or if an acute total hip arthroplasty was performed at the time of index surgery. INTERVENTION: XRT. MAIN OUTCOME: Severe HO (Brooker class III or IV). RESULTS: The severe HO (Brooker class III or IV) rate for entire cohort was 12% (44 of 361 patients). Of these 44 patients, 30 patients were classified as Brooker III and 14 patients were classified as Brooker IV. The Brooker IV rate for the entire cohort was 4% (14 of 361 patients). Severe HO rates showed a declining trend over the period examined, with a risk reduction of -1.0% per year (95% confidence interval -2.1% to 0.2%; P = 0.10). CONCLUSION: To our knowledge, this is the largest single consecutive series on acetabular fracture patients who received XRT as HO prophylaxis. The overall severe HO rate was 12%, which is similar to other comparably large series data on patients who did not receive XRT after surgical fixation acetabular fractures. Although these data suggest that XRT may not be beneficial when used universally for all patients, comparative studies are required to rule out the benefits of XRT for preventing HO in this population. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Prevalence, diagnosis, and impact on clinical outcomes of dural ossification in the thoracic ossification of the ligamentum flavum: a systematic review.

STUDY DESIGN: Systematic review. BACKGROUND CONTEXT: Thoracic ossification of the ligamentum flavum (TOLF) has become the principal cause of thoracic spinal stenosis. Dural ossification (DO) was a common clinical feature accompanying with TOLF. However, on account of the rarity, we know little about the DO in TOLF so far. PURPOSE: This study was conducted to elucidate the prevalence, diagnostic measures, and impact on the clinical outcomes of DO in TOLF by integrating the existing evidence. METHODS: PubMed, Embase, and Cochrane Database were comprehensively searched for studies relevant to the prevalence, diagnostic measures, or impact on the clinical outcomes of DO in TOLF. All retrieved studies meeting the inclusion and criterion were included into this systematic review. RESULTS: The prevalence of DO in TOLF treated surgically was 27% (281/1046), ranging from 11 to 67%. Eight diagnostic measures have been put forward to predict the DO in TOLF using the CT or MRI modalities, including "tram track sign", "comma sign", "bridge sign", "banner cloud sign", "T2 ring sign", TOLF-DO grading system, CSAOR grading system, and CCAR grading system. DO did not affect the neurological recovery of TOLF patients treated with the laminectomy. The rate of dural tear or CSF leakage in TOLF patients with DO was approximately 83% (149/180). CONCLUSION: The prevalence of DO in TOLF treated surgically was 27%. Eight diagnostic measures have been put forward to predict the DO in TOLF. DO did not affect the neurological recovery of TOLF treated with laminectomy but was associated with high risk of complications.

Simplified biplanar classification for heterotopic ossification is more predictive of patient-reported outcomes than the Brooker classification after anterior total hip arthroplasty.

BACKGROUND: Heterotopic ossification (HO) commonly occurs after total hip arthroplasty (THA) and can adversely impact clinical outcomes. The purpose of this study is to propose a more reliable HO grading method that is better predictive of patient-reported outcomes (PROs) after THA than the Brooker classification. METHODS: 513 THAs (62 ± 10 years old) were reviewed. The incidence and grade of HO was evaluated using the Brooker grading system and a simplified biplanar classification system (grade 1: ⩾1 cm between bone on both anteroposterior and lateral views, grade 2: <1 cm between bone on either view). The modified Harris Hip Score (mHHS), Forgotten Joint Score (FJS), and visual analogue scale (VAS) for pain were collected at minimum of 2 years after surgery and were compared between HO grades using multiple regression models. RESULTS: The incidence of HO varied by Brooker grade (grade 1, 23.4%; grade 2, 22.4%; grade 3, 7.2%; grade 4, 0%) and biplanar grade (grade 1: 45.6%; grade 2: 7.4%). The biplanar classification demonstrated higher interobserver reliability than the Brooker classification (κ = 0.95 and 0.91, respectively). Brooker grade 3 HO decreased the mHHS by 6.5 (standard error: 2.7) but did not have a significant effect on FJS or VAS. Biplanar grade 2 HO decreased the mHHS by 9.9 (standard error: 2.7), the FJS by 12.9 (standard error: 4.51) and increased the VAS pain score by 0.81 (standard error: 0.35). The Cox test was used to compare the fit of regression models and determined the biplanar classification was a significantly better predictor than the Brooker classification (p < 0.001). CONCLUSIONS: Biplanar grade 2 HO had a significant negative influence on PROs. Contrary to previous literature, these results show clinical significance of non-bridging HO. Compared with the Brooker classification, the biplanar classification has greater interobserver reliability and is more predictive of outcomes after THA.

Surgical Resection Combined with Adjuvant Radiotherapy and Non-Steroidal Anti-Inflammatory Drugs in the Treatment of Heterotopic Ossification Following Total Hip Arthroplasty.

Heterotopic ossification (HO) is a well-known complication following total hip arthroplasty (THA), with an average incidence of 30%. Patients are classified according to Brooker's staging system. In advanced stages (III and IV), HO may limit hip motion and cause intolerable pain. For these symptomatic stages, surgical excision is mandatory, usually combined with prophylaxis of recurrence with non-steroidal anti-inflammatory drugs (NSAIDs) and/or radiotherapy. We present the case of a 70-year-old woman who developed Stage IV HO after undergoing THA for left hip osteoarthritis. Surgical excision of the HO was performed eighteen months after THA, with adjuvant radiotherapy and indomethacin. After two years of follow-up, the patient had a good hip function with no recurrence of HO. Several authors have studied the effect of NSAIDs and radiotherapy in HO prophylaxis and in HO treatment but there is lack of reports concerning the combination of the two strategies with surgery in the postoperative period. We therefore report this successful case of post-THA HO treatment with surgical excision and post-operative radiotherapy and NSAIDs.

A ossificação heterotópica (OH) é uma complicação frequente após artroplastia total da anca (ATA), com uma incidência média de 30%. Os doentes são classificados de acordo com o sistema de estadiamento de Brooker. Nos estádios avançados (Brooker III e IV), a OH pode restringir a mobilidade da anca e causar dores insuportáveis. Nestes estádios sintomáticos, o tratamento indicado consiste na excisão cirúrgica combinada com profilaxia da recorrência com anti-inflamatórios não esteróides (AINEs) e/ou radioterapia. Apresentamos o caso de uma mulher de 70 anos que desenvolveu OH grau IV após ATA por osteoartrose da anca esquerda. Realizou-se excisão da OH um ano e meio após a ATA, com radioterapia e indometacina adjuvantes. Após dois anos de seguimento, não se verifica recorrência da OH e apresenta uma boa função da anca. O efeito dos AINEs e radioterapia adjuvante na profilaxia e no tratamento da HO está bem estabelecido, mas não há muitos relatos das duas estratégias combinadas com cirurgia no pós-operatório. Descrevemos, portanto, um caso de tratamento de OH pós-ATA com excisão das ossificações e radioterapia e AINEs no pós-operatório.

Incidence and risk factors of dural ossification in patients with thoracic ossification of the ligamentum flavum.

OBJECTIVE: Dural ossification (DO) is a common clinical feature in patients with thoracic ossification of the ligamentum flavum (OLF) and associated with the increased risk of perioperative complications. However, few studies have been conducted to determine the incidence and independent risk factors of DO in patients with thoracic OLF. The aim of this retrospective study was to determine the incidence and independent risk factors of DO in patients with thoracic OLF. METHODS: A total of 107 patients with thoracic OLF who were admitted to the authors' hospital from December 2020 to December 2021 were included in this study. The independent risk factors of DO in patients with thoracic OLF were determined through univariate analysis followed by multivariate logistic regression analysis with p < 0.05. The diagnostic efficacy of the DO in OLF (DO-OLF) risk classification model was determined on the basis of independent risk factors and evaluated on the basis of sensitivity, specificity, and agreement rate. RESULTS: The incidence of DO in patients with thoracic OLF was 35% (37/107 patients). The tuberous type according to the Sato classification (OR 9.75, p < 0.01) and larger (≥ 9°) supine local kyphosis angle (LKA) (OR 8.13, p < 0.01) were two independent risk factors of DO in thoracic OLF. The DO-OLF risk classification, a novel approach for the diagnosis of DO in patients with thoracic OLF, was established on the basis of the combination of the tuberous type according to the Sato classification and larger supine LKA. The sensitivity, specificity, and agreement rate of this approach for distinguishing between patients with thoracic OLF at high and low risk of DO were 87%, 93%, and 91%, respectively. CONCLUSIONS: The incidence of DO in patients with thoracic OLF was 35%. The tuberous type according to the Sato classification and larger supine LKA (≥ 9°) were independent risk factors of DO in patients with thoracic OLF. The novel DO-OLF risk classification approach could serve as an efficient method for predicting DO in patients with thoracic OLF.

Heterotopic Ossification Prophylaxis in Acetabular Fracture Surgery: A Systematic Review.

Heterotopic ossification (HO) following acetabular fracture surgery is relatively common. The purpose of this study was to perform a systematic review of the literature regarding HO rates following acetabular surgery and the effectiveness of the various prophylactic measures taken to prevent its occurrence. A search of PubMed, MEDLINE, and Cochrane Database of Systematic Reviews was performed using the search terms ("Acetabular" OR "Acetabulum") AND ("Heterotopic Ossification" OR "HO" OR "Ectopic Ossification"). Inclusion criteria included articles published in English reporting on HO in acetabular fracture surgery. Descriptive statistics were calculated with categorical data presented as frequency with percentages and continuous data as means. Standard weighted means were calculated for all parameters. Sixty-six articles were included in this study with a total of 5,028 patients. HO was identified in 1,511 (30%) of fractures. Indomethacin (27%) and radiation therapy (24%) demonstrated decreased rates of HO formation versus no prophylaxis (36%). In particular, rates of severe HO formation were substantially decreased with radiation therapy (3%) and indomethacin (7%) compared to no prophylaxis (18%). Indomethacin and radiation therapy both appear to decrease HO formation and severity without substantially increasing surgical morbidity. (Journal of Surgical Orthopaedic Advances 32(4):217-224, 2023).

Could temporary external fixation after reduction of displaced acetabular fractures prevent posttraumatic heterotopic ossification?

OBJECTIVES: To recommend appropriate immobilization after the initial reduction of acetabular displaced fractures in order to minimize the risk of heterotopic ossification formation. DESIGN: Retrospective study of patients treated in our surgical department during the years 2005-2018. MATERIALS AND METHODS: There were 94 patients included in statistical analysis. The factors of injury severity, course of surgery and hospitalization and incidence of complications were recorded. The functional and X-ray results were evaluated at least one year after surgery. RESULTS: The patients were divided into the two groups according to the type of fixation after closed reduction, the external fixation (EF) and the skeletal traction (ST) group. According to the type of fracture there were 33 patients with central displacement and 61 patients with posterior displacement. Ossification grade III. And IV. Occur in 20% of our sample. There was greater incidence of Brooker grade III. And IV. Ossification in the ST group, but statistically insignificant, p = 0.57. There was no statistically significant difference in the occurrence of ossifications regarding the severity of the head injury, p = 0.11, or to the severity of the injury p = 0.54. The combination of posterior displacement and ST results in higher risk for ossifications, specifically in our group at 11.48% compared to the combination of posterior displacement and EF where it is 8.2%. CONCLUSION: Skeletal traction for posterior displaced acetabular fracture appears to be a more risky procedure for the development of ossifications than external fixation.

Does drainage affect development of heterotopic ossification after total hip arthroplasty?

OBJECTIVE: To investigate the effect of drainage on heterotopic ossification (HO) after total hip arthroplasty (THA) and to evaluate other postoperative complications and joint dysfunction between patients with and without drainage. METHODS: In this retrospective cohort study, the medical records of patients who underwent THA from 2017 to 2019 were reviewed. The patients were divided into a drainage group and non-drainage group. Standard preoperative anteroposterior and lateral radiographs were assessed by senior radiologists for HO analysis. Clinical indicators included the hemoglobin concentration, superficial infection, blood transfusion, hematoma formation, hip range of motion (ROM), erythrocyte sedimentation rate, C-reactive protein concentration, dressing changes, visual analogue scale score, and Harris Hip Score (HHS). RESULTS: The incidence of HO was significantly higher in the drainage than non-drainage group (32.0% vs. 16.3%). The presence of severe HO (Brooker grade III or IV) was also different between the groups. Patients in the non-drainage group had smaller ROM early after surgery, but the final ROM and HHS did not differ significantly between the groups. CONCLUSIONS: The rate and degree of HO after THA were significantly different between patients with and without drainage. There is no added advantage of closed suction drainage over no drainage in primary THA.

Significance of body mass index on thoracic ossification of the ligamentum flavum in Chinese population.

PURPOSE: To investigate the risk factors for thoracic ossification of the ligamentum flavum (TOLF), especially the relationship between BMI and TOLF. METHODS: A total of 856 individuals consisting of 326 controls without ossification of spinal ligaments and 530 TOLF inpatients who underwent thoracic spine decompression surgery at our hospital between January 2013 and September 2020 were included. All subjects were classified into 4 grades: Grade 0) control; Grade 1) single-segment TOLF; Grade 2) multi-segment TOLF; and Grade 3) TOLF combined thoracic ossification of the posterior longitudinal ligament (T-OPLL). Logistic regression analysis was performed to identify the risk factors for TOLF. The TOLF index was calculated to assess the severity of TOLF, and its relationship with BMI was investigated by correlation analysis. RESULTS: Overall, TOLF patients are most numerous in the 50-59 age group. Age and gender were considered as independent risk factors for Grades 1 and 2. BMI was identified as an independent risk factor for TOLF. Furthermore, BMI was significantly higher in Grade 1 (26.1 VS 24.5 kg/m2, P = 0.0001), Grade 2 (28.2 VS 24.5 kg/m2, P < 0.0001), and Grade 3 (29.1 VS 24.5 kg/m2, P < 0.0001) than Grade 0. Notably, in TOLF patients without combined T-OPLL, BMI was positively correlated with TOLF index, while BMI was negatively correlated with age in younger individuals. CONCLUSION: BMI is a crucial risk factor for TOLF. It highlights the necessity of close follow-up of asymptomatic TOLF patients with high BMI to detect and treat their TOLF progression promptly.

Heterotopic ossification after alloplastic temporomandibular joint replacement: a case cohort study.

BACKGROUND: Heterotopic ossification (HO) is one of the serious complications leading to the failure of alloplastic temporomandibular joint replacement (TJR). However, there was few research on its exact incidence and occurrence. Severe HO might result in pain and limited mouth opening after surgery. Therefore, it is necessary to clarify its clinical and imaging manifestations. The purpose of this study was to study the occurrence and classify HO after the alloplastic TJR. METHOD: Patients who underwent standard TJR (Zimmer Biomet stock prostheses or Chinese stock prostheses) with fat graft and at least 1-year-follow-up were included. HO was classified into 4 types according to postoperative computed tomography (CT) scans. Type and occurrence in different TMJ disease were compared. Joint space within 1 week after operation was measured and compared between HO and non-HO TJRs. Maximum incisal opening (MIO), pain, and quality of life (QoL) were recorded and their relevance with HO was analyzed statistically. RESULT: 81cases with 101 joints were included in the study. The mean follow-up time was 22.9 months (12 ~ 56 months). Among the 48 joints, 27 (56.3%) were type I (bone islands); 16 (33.3%) were type II (bone spurs from the mandibular ramus); 3 (6.3%) were type III (bone spurs from the fossa); and 2 (4.2%) were type IV (bone spurs from both the mandibular ramus and fossa). In HO patients, joint space in type IV was smaller than the other 3 types. Pain scores in HO were significantly greater than non-HO patients before and after operations (p < 0.05). 1 patient in Type IV HO developed ankylosis and had prosthesis revision which accounted for 2.1% in HO patients and 1.0% in all TJR patients. CONCLUSION: HO after alloplastic TJR with fat graft was not severe except for type IV, which was easy to cause ankylosis. Preserving sufficient TJR space was important for ankylosis prevention.