Higher Incidence Of Heterotopic Ossification Research Articles

Long-term outcomes of anterior cervical dynamic implants: motion-sparing or a delayed fusion?

Background ContextUse of an anterior cervical dynamic implant (ACDI) is generally considered a nonfusion technique for treating cervical degenerative disorders. However, there is limited research focused on evaluating the long-term clinical and radiographic outcomes of ACDI. PurposeTo analyze the long-term clinical and radiographic outcomes of ACDI in the treatment of degenerative cervical disorders. Study DesignA retrospective cohort study. Patients SamplePatients with degenerative cervical disorders who underwent anterior cervical discectomy and dynamic cervical implant (DCI) implantation between May 2012 and August 2020 at our institution were included in this study. Outcome MeasuresClinical outcomes were assessed using the modified Japanese Orthopedic Association (mJOA), visual analog scale (VAS) scores and patient reported satisfaction rate. Imaging assessment parameters included intervertebral height (IH), intervertebral disc height (IDH), C2-7 range of motion (ROM), segmental ROM, the degree of DCI subsidence and anterior migration, heterotopic ossification (HO) as well as adjacent segment degeneration (ASD). MethodsJOA and VAS scores were obtained through questionnaire. The patient reported satisfaction was rated as very satisfied, satisfied, less satisfied and dissatisfied at the final follow-up. The position of the implants, IDH and IH were evaluated on lateral radiographs. ROM at C2-7, ROM at operated level were measured on dynamic radiographs. Cervical 3 -dimensional computer tomography (CT) and magnetic resonance image (MRI) images were used to assess the presence of HO and ASD. The clinical and radiologic variables between the preoperative period and different follow-up time point were statistically analyzed by unpaired t-tests or chi-square tests. Statistical significance was defined as p<.05. ResultsA total of 92 patients (51 males and 41 females) were included in this study. Among them, there were 36 cases of cervical spondylotic myelopathy, 26 cases of cervical radiculopathy, and 30 cases of myeloradiculopathy. The mean age was 55.1±12.6 years. The number of operated levels was single level in 57 patients, 2 levels in 31 patients, and 3 levels in 4 patients. The average follow-up period was 81.3 months (range: 35-135 months). The mean JOA scores showed a gradual increase at 1 month, 1 year, and the final follow-up (12.0±0.7,13.5±0.8, and14.4±1.1 respectively) compared to the preoperative score (9.1±0.9, p<.01). VAS scores significantly decreased at 1 month, 1 year, and the final follow-up (4.1±0.7, 2.3±0.9, and 2.0±0.8 respectively) compared to the preoperative score (7.2±l .2, p<.01). At the final follow-up, the patient reported satisfaction was rated as very satisfied, satisfied, less satisfied and dissatisfied (79%, 10%, 10%, 1% respectively). Revision surgery was not required for any of the patients during the follow-up period, either due to instrumentation failure or adjacent segmental diseases. In the radiographic assessment, there was a notable increase in IH and IDH after surgery compared to preoperative values (33.0±4.0 mm vs. 30.7±3.0 mm, p<.01 and 6.7±2.4 mm vs. 4.6±0.9 mm, p<.01 respectively), which gradually decreased at 1 year and the final follow-up (IH: 32.1±2.5 vs. 30.9±3.5 p=.024; IDH: 5.3±1.5 mm vs. 4.3±0.6 mm, p=.043 respectively). At the 1-month postoperative follow-up, the segmental ROM exhibited a decrease compared with preoperative values (6.2±1.8° vs. 7.5±2.0° p=.044), followed by an increase at the 1-year follow-up (6.2±1.8° vs. 6.4±1.5° p=.078), but ultimately decreased at the final follow-up (6.4±1.5° vs. 2.9±0.6°, p<.01). HO was observed in approximately 81.5% of cases (75/92), while a great proportion (41.3%) of patients experienced varying degrees of prosthesis subsidence and anterior migration during the follow-up. ConclusionAt the long-term follow-up, a high incidence of HO, along with varying degrees of subsidence and migration of the prosthesis, were observed in most patients. As the motion preservation capability of the ACDI gradually diminishes, delayed intervertebral autofusion becomes a more likely outcome compared to motion sparing.

Local BMP2 hydrogel therapy for robust bone regeneration in a porcine model of Legg-Calvé-Perthes disease

Legg-Calvé-Perthes disease is juvenile idiopathic osteonecrosis of the femoral head (ONFH) that has no effective clinical treatment. Previously, local injection of bone morphogenetic protein-2 (BMP2) for ONFH treatment showed a heterogeneous bone repair and a high incidence of heterotopic ossification (HO) due to the BMP2 leakage. Here, we developed a BMP2-hydrogel treatment via a transphyseal bone wash and subsequential injection of BMP2-loaded hydrogel. In vitro studies showed that a hydrogel of gelatin-heparin-tyramine retained the BMP2 for four weeks. The injection of the hydrogel can efficiently prevent leakage. With the bone wash, the injected hydrogel had a broad distribution in the head. In vivo studies on pigs revealed that the BMP2-hydrogel treatment produced a homogeneous bone regeneration without HO. It preserved the subchondral contour and restored the subchondral endochondral ossification, although it increased growth plate fusions. In summary, the study demonstrated a promising BMP2-hydrogel treatment for ONFH treatment, especially for teenagers.

Is a primary distal biceps tendon repair a matter of time? Comparison of functional outcome in a retrospective case-control study

Acute tendon ruptures are not always promptly recognized or referred appropriately, creating a delayed patients presentation to the surgeon. Previous reports have noted an increased complication rate of patients with a delay to surgery, however, there is a paucity of literature reporting functional outcomes of chronic/delayed distal biceps repair. With our clinical experience, we noticed that a chronic distal biceps tendon rupture can safely be directly repaired to the radial tuberosity. We hypothesized that delayed primary distal biceps tendon repair (> 21 days from injury) has similar functional outcomes and complication rate, compared to acute repair. A retrospective case-control study was used to compare the delayed (study) and acute (control) primary distal biceps tendon repair, performed between January 2017 and December 2021. Strength measurements were noted as a percentage of the unaffected contralateral side. Functional outcomes were recorded using the Visual Analog Scale, the Mayo Elbow Performance Score, the short version of the Disabilities of the Arm, Shoulder and Hand score and the Patient-Rated Elbow Evaluation. All questionaries, including Satisfaction, were completed at the final follow-up. All clinical records were evaluated for any adverse events. We selected 210 out of 217 patients. The study and control cohort consisted of 75 and 135 patients respectively. Time to surgery was 73 ± 66.05 days versus 11.27 ± 5.14 days respectively. At short term (4.79 ± 2.09 months), the functional outcome in terms of Mayo Elbow Performance Score, the short version of the Disabilities of the Arm, Shoulder and Hand score and the Patient-Rated Elbow Evaluation were statistically not significant different ( P = 0.354, P = 0.412 and P = 0.958, respectively). The mean flexion and supination strength were respectively 89.19 ± 13.43% and 77.48 ± 16.68%, similar for both cohorts ( P = 0.476 and P = 0.395, respectively). Significantly higher incidence of asymptomatic heterotopic ossification in the control cohort ( P = 0.006), however not difference in overall complication rate ( P = 0.072). At long term (28.9 ± 17.9 months), the functional outcomes remain similar. This study demonstrates that delayed primary distal biceps repair is reliable and overall safe Functional outcomes and strength did not changed with a delayed repair. There was a higher incidence of heterotopic ossification in acute distal biceps repair. The overall complication rate was similar, no matter what time to surgery.

A Meta-analysis Comparing External Fixation against Open Reduction and Internal Fixation for the Management of Tibial Plateau Fractures.

AimThis article aims to compare the outcomes between open reduction and internal fixation (ORIF) and external fixation (ExFix) in tibial plateau fractures.BackgroundOpen reduction and internal fixation and external fixation are common methods for managing tibial plateau fractures without a consensus of choice.Materials and methodsPubMed, Cochrane Library, Ovid, CINAHL®, Scopus, and Embase were searched. Clinical studies in humans comparing ExFix and ORIF for tibial plateau fractures were included. Case reports, pathological, and biomechanical studies were excluded. Two investigators reviewed the studies independently, and any discrepancies were resolved. The quality and heterogeneity of each study were assessed in addition to calculating the odds ratio (OR) of the surgical outcomes and complications at a 95% confidence interval, with p <0.05 as statistical significance.ResultsOf the 14 included studies, one was a randomised trial, one was a prospective study, and 12 were retrospective studies. The 865 fractures identified across the studies constituted 458 (52.9%) in the ExFix group and 407 (47.1%) in the ORIF group. Most studies indicated a better outcome for ORIF as compared to ExFix. Open reduction and internal fixation had a lower incidence of superficial infection and postoperative osteoarthritis, while ExFix revealed a lower proportion with heterotopic ossification (HTO).ConclusionExFix has a higher rate of superficial infections and osteoarthritis, whereas ORIF has a higher incidence of HTO. Larger studies are needed to compare outcomes and investigate the findings of this study further.Clinical significanceThis up-to-date meta-analysis on tibial plateau management will help surgeons make evidence-based decisions regarding the use of ORIF versus ExFix.How to cite this articleNaja AS, Bouji N, Eddine MN, et al. A Meta-analysis Comparing External Fixation against Open Reduction and Internal Fixation for the Management of Tibial Plateau Fractures. Strategies Trauma Limb Reconstr 2022;17(2):105–116.

Heterotopic ossification in a patient with diffuse idiopathic skeletal hyperostosis: Input from histological findings.

A high incidence of heterotopic ossification (HO) has been reported in patients with diffuse idiopathic skeletal hyperostosis (DISH), a metabolic disease characterized by calcifications of entheses at spine and peripheral sites. We performed histological and immunohistochemical analyses in five different HO sites in a patient with DISH to study a possible mutual interaction of bone morphogenetic protein 2 (BMP-2), transforming growth factor beta (TGF-β), and decorin, crucial for bone mass increasing, matrix calcification, and endochondral bone formation. We speculated that the surgical trauma triggered HO, inducing TGF-β release at the lesion site. TGF-β recruits osteoblast precursor cells and determines the overexpression of BMP-2 in the surrounding skeletal muscle, inducing a further osteogenic differentiation, contributing to HO onset.

The Development of Heterotopic Ossification Following Ankle Fracture Syndesmotic Screw Fixation

Category:Ankle, TraumaIntroduction/Purpose:Syndesmotic fixation with screws is commonly used for ankle fractures with syndesmotic disruption. Few studies have reported the development of heterotopic ossification (HO) within the syndesmosis following ankle injuries, which may lead to abnormal joint kinematics and even joint synostosis. However, there is little data on the prevalence and on the risk factors associated with the development of HO. The purpose of this study is to determine the (1) prevalence and (2) risk factors associated with the development of HO within the distal tibiofibular syndesmosis following ankle fractures requiring syndesmotic fixation. We hypothesized that screws within the syndesmosis articulation and broken screws would be associated with a higher incidence of HO than extraarticular and intact screws, respectively.Methods:A retrospective review was conducted for patients who sustained an ankle fracture with syndesmotic disruption. Inclusion criteria: age between 18 and 65 years old, a closed ankle fracture treated operatively with syndesmotic screw fixation. Exclusion criteria: additional lower extremity injury, history of prior ankle fracture, lack of radiographic follow-up and fixation other than 1 or 2 syndesmosis screws.Medical records were reviewed for: age, sex, high or low energy injury mechanism, smoking status, diabetes, BMI, perioperative complications, and further procedures. Fractures were classified by Lauge-Hansen and Weber systems. Immediate postoperative radiographs were reviewed for the number of syndesmotic screws, whether screws were intraarticular or extraarticular and the number of cortices each screw crossed. Final postoperative radiographs were reviewed for retention or screw removal and the presence of HO. The presence of HO was defined as new or increased bone formation within the syndesmosis compared to immediate postoperative radiographs.Results:Included were 264 patients, mean radiographic follow-up of 10.5+/-10.2 months. The mean age was 39.2+/-12.6 years (38.7% female) with a mean BMI of 32.1+/-7.8. Current smokers made up 39.4% of patients and 10.6% were diabetic. The mean time to fracture fixation was 12.6+/-3.2 days and 198 patients (75%) had a low energy injury. There was no significant difference in HO formation for demographics, injury mechanism or time to fixation. Overall, HO developed in 160 patients (60.6%). There was no difference, additionally for fracture pattern, number screws or fixation construct (Table 1). HO developed in 92% of broken, 75% of loose and 44% of intact screws (P<0.001). Screws were removed in 107 patients (40.5%) with no difference in HO formation compared to patients with intact screws.Conclusion:Heterotopic ossification is commonplace following screw fixation for syndesmotic injuries with a prevalence of 60.6%. Broken screws and loosened screws are a significant risk factor for the development of HO. However, no other risk factors in this study were found to be associated with the development of HO, including intraarticular syndesmotic screw placement. Patients should be counseled on the prevalence although further research is needed to determine the effect on ankle motion and progression of post-traumatic osteoarthritis.

Multilevel cervical arthroplasty: current evidence. A systematic review.

OBJECTIVE Cervical disc arthroplasty (CDA) has been demonstrated to be an effective treatment modality for single-level cervical radiculopathy or myelopathy. Its advantages over an anterior cervical discectomy and fusion (ACDF) include motion preservation and decreased reoperations at the index and adjacent segments up to 7 years postoperatively. Considering the fact that many patients have multilevel cervical disc degeneration (CDD), the authors performed a systematic review of the clinical studies evaluating patients who underwent multilevel CDA (2 or more levels). METHODS A systematic review in the MEDLINE database was performed. Clinical studies including patients who had multilevel CDA were selected and included. Case reports and literature reviews were excluded. Articles were then grouped according to their main study objective: 1) studies comparing multilevel CDA versus ACDF; 2) studies comparing single-level CDA versus multilevel CDA; and 3) multilevel CDA after a previous cervical spine surgery. RESULTS Fourteen articles met all inclusion criteria. The general conclusions were that multilevel CDA was at least as safe and effective as ACDF, with preservation of cervical motion when compared with ACDF and potentially with fewer reoperations expected in most of the studies. Multilevel CDAs are clinically effective as single-level surgeries, with good clinical and radiological outcomes. Some studies reported a higher incidence of heterotopic ossification in multilevel CDA when compared with single-level procedures, but without clinical relevance during the follow-up period. A CDA may be indicated even after a previous cervical surgery in selected cases. CONCLUSIONS The current literature supports the use of multilevel CDA. Caution is necessary regarding the more restrictive indications for CDA when compared with ACDF. Further prospective, controlled, multicenter, and randomized studies not sponsored by the device manufactures are desirable to prove the superiority of CDA surgery over ACDF as the treatment of choice for CDD in selected cases.

The long and short of cephalomedullary nails in the treatment of osteoporotic pertrochanteric fracture.

Pertrochanteric fractures after low-energy trauma are common among osteoporotic patients. Although the use of intramedullary devices to treat such fractures is becoming increasingly popular, there is a paucity of data comparing the outcomes of the use of short cephalomedullary nails (SCN) with the use of long cephalomedullary nails (LCN). This study aimed to compare the outcomes of treatment using LCN with treatment using SCN for patients with osteoporotic pertrochanteric fractures. A retrospective review of 64 patients with osteoporotic pertrochanteric fractures who were treated with either LCN or SCN and had a minimum follow-up of one year was performed. Primary outcome measures include complications, revision surgeries and union rates. Secondary outcome measures include duration of surgery, estimated blood loss, length of hospital stay, and ambulatory and mortality status at one year. There was no significant difference in the clinical and functional outcomes of the patients who were treated with LCN and those who were treated with SCN. However, there was a higher incidence of heterotopic ossification in the latter group, and a slightly greater average estimated blood loss and duration of surgery in the former group. Patients treated with LCN tended to be more osteoporotic. Our study found no significant difference in terms of complications, revision surgeries, union rates and ambulatory status between the patients who were treated with LCN and those who were treated with SCN. Both LCN and SCN provided safe and reliable outcomes in the treatment of osteoporotic pertrochanteric fractures.

Introduction: Minimally invasive spine surgery: the greatest advance in medicine?

In the past century, significant advances have been made in spine surgery, and in this issue of Neurosurgical Focus, we will review the myriad of treatment options currently available to treat spinal disorders. These minimally disruptive techniques and approaches to the spine have dramatically altered the natural history of previously difficult lesions and spinal conditions. Harvey Cushing would be proud of the work done in the fields of neurosurgery, radiology, engineering, physics, and orthopedics for the advancement of spine surgery. In modern medicine, there are few advances that have had a more meaningful impact on patient outcomes than minimally invasive spine procedures. Patients presenting with painful radiculopathies and neural compression can be treated successfully with minimal access procedures and sent home the same day. Sven Eicker and colleagues discuss their experience with extraforaminal lumbar disc herniations. Their minimal access microsurgical approach with the endoscopic technique seemed to produce less tissue trauma and instability, while providing significant improvement of functional outcomes. Surgical management of tumors, fractures, and spinal deformities has significantly improved with these emerging technologies and techniques. Percutaneous ped icle screw fixation for spine fractures can be done with minimal blood loss, and patients can be mobilized immediately, resulting in a decrease in postsurgical complications. Flexion-distraction spine injuries, which are extremely unstable, classically consisting of a fracture line through all 3 columns, require surgical fixation to avoid neurological deterioration, help stabilize the spine, and restore spinal balance. Historically, these injuries were all treated by means of the standard posterior open approach with instrumented fusion. Percutaneous pedicle screw fixation for these unstable spine injuries has been recently reported in the literature. Andrew Grossbach and colleagues report on their institutional experience of treating these fractures with both surgical techniques and review the current literature. Although it was a small prospective study, there was improvement in kyphotic angulation, and the authors found no significant difference in ASIA scores or the degree of kyphotic angulation between the percutaneous and open surgical groups. Percutaneous pedicle screw fixation appeared to have similar efficacy in the treatment of flexion-distraction injuries, and it allowed for reduced blood loss and tissue damage compared to open surgical techniques. Instrumentation systems have improved significantly in the past 10 years, and today’s hardware allows surgeons to realign the spine and contour the rod to the spine. How about treating spinal stenosis and spondylolisthesis with a minimally invasive interspinous fixation device? Nai-Feng Tian and colleagues found that there was a high incidence of heterotopic ossification after interspinous fixation. Lateral approaches have been applied to treat spinal conditions, such as scoliosis, in recent years. The prior treatment deformity paradigms of shortening the spine by performing osteotomies posteriorly are utilized less. Scoliosis procedures can now be staged with multilevel lateral cages that lengthen the spine, correct the deformity, increase spinal balance, provide a more natural curve, and indirectly decompress neural elements. Armen Deukmedjian and coauthors reviewed their lateral approach for adult degenerative scoliosis. They provided useful data about patient selection for the application of lateral approaches for adult scoliosis surgery. Isolated lateral interbody fusions were deemed suitable for patients with preserved spinal pelvic harmony. Sagittal imbalance may be addressed with advanced lateral approaches, such as releasing the anterior longitudinal ligament. Is there a role for minimally disruptive procedures in the treatment of intradural pathology? The article by Gandhi et al. eloquently describes utilizing a paramedian minimally invasive tubular retractor to access the spine and microscopic instruments to remove intradural pathology. Historically, intradural spinal lesions have been treated from a midline posterior approach using standard microsurgical techniques. The authors retrospectively reviewed their operative blood loss, length of stay, imaging characteristics, and outcomes. Introduction

High prevalence of heterotopic ossification after cervical disc arthroplasty: outcome and intraoperative findings following explantation of 22 cervical disc prostheses

Cervical disc arthroplasty (CDA) has been increasingly used for the treatment of cervical disc herniations. However, the impact of CDA on adjacent-segment degeneration and the degree of heterotopic ossification (HO) of the treated segment remain a subject of controversy. Due to a product failure of the Galileo-type disc prosthesis, 22 of these devices were explanted. The radiological and clinical course in each case was investigated in detail with an emphasis on the incidence of HO and facet joint degeneration 18 months following the operation. Intraoperative findings regarding ossification and implant fixation were documented. Thus, the authors were able to describe the true rate of adjacent-segment degeneration and HO following CDA and the clinical relevance thereof. In all 22 patients, functional radiographic imaging was performed prior to surgery, 3 and 12 months after surgery, and prior to disc prosthesis explantation. At all time points, the range of motion (ROM) in the operated and adjacent segments was determined. A motion index was calculated using the preoperative and all postoperative ROMs (preoperative ROM/postoperative ROM). Computed tomography was used preoperatively to measure the height of the index segment, extent of HO, and the degree of the progression of facet arthrosis, and was used postoperatively prior to prosthesis explantation. Patients completed clinical questionnaires that included a visual analog scale and the Neck Disability Index. The motion index of the index segment declined gradually from 1.4 at 3 months postoperative to 1.2 prior to explantation, while the motion index of the adjacent upper segment increased from 0.9 to 1.3. The mean ROM of the index segment was 10.4° ± 6.7°, and fusion was observed in 2 (9%) of the 22 patients. Prosthesis migration was present in 3 patients (13.6%). Severe HO (Grades 3 and 4) was present in 17.4%. Computed tomography showed a significant increase of segmental height of the index segment (1.6 ± 1.1 mm, p = 0.035), and a significant increase of left-sided lateral osteophytes (1.7 ± 2.1 mm, p = 0.009). The incidence of severe osteophyte formation (> 2 mm) occurred in 40%. Intraoperative findings reflected the results from CT, with primary lateral proliferation of osteophytes found in approximately 25% of patients. The mean visual analog scale scores were 3.8 ± 2.7 (neck) and 2.4 ± 2.5 (arms), and the mean Neck Disability Index score was 30 ± 22. No correlation was found between radiological and clinical parameters. In this study, a higher incidence of HO after CDA could be demonstrated using CT, compared with studies using fluoroscopy only. However, patient selection and/or the operative technique might have contributed to the high prevalence of osteophyte formation. Thus, the exact indication for CDA has to be reconsidered. Because implant migration was detected, using fixation in the present CDA model appears suboptimal.

The impact of class III (morbid) obesity on heterotopic ossification outcomes

PurposeObesity is associated with a chronic low inflammatory process that may act as common soil for the pathogenesis of obesity-related comorbidities including heterotopic ossification (HO). The purpose of this study is to compare the incidence of HO between patients with body mass index (BMI) <40 versus ≥40 after operative treatment of displaced acetabular fractures followed by radiation therapy (RT) ± indomethacin. Methods and MaterialsThis is a single institution retrospective chart review of 419 patients. All patients with well-documented BMI underwent operative treatment followed by RT ± indomethacin. All patients received 700 cGy to the soft tissues around the proximal femur and acetabulum without bone shielding. All RT were given postoperatively within 72 hours. The patients were divided into 2 groups: Group (A) BMI < 40 and Group (B) BMI ≥40. HO was assessed with X-ray. BMI was used as a surrogate measure to test the risk of HO despite prophylaxis. ResultsThe incidence of HO among all patients is 21% (89 of 419), while among those in group A (BMI <40), 68 of 374 patients developed HO (18%); in the morbidly obese group (BMI ≥40) 21of 45 patients developed HO (47%). The difference between the rates of HO in the 2 groups was 29%; the χ2 test showed a significant difference between the 2 BMI groups (P < .001 at α = 0.05). ConclusionsThere is a higher incidence of HO among the morbidly obese patients despite RT ± indomethacin. RT doses for HO prophylaxis in morbidly obese patients need to be reassessed; also, understanding the signaling pathways in target tissues in obese patients at which adipokines control metabolism may reveal novel therapies. Higher radiation doses ± indomethacin may need to be considered and optimally evaluated in the context of a prospective, randomized clinical trial.

Early development and progression of heterotopic ossification in cervical total disc replacement

The purpose of cervical total disc replacement (TDR) is to decrease the incidence of adjacent segment disease through motion preservation. Heterotopic ossification (HO) is a well-known complication after hip and knee arthroplasties. There are few reports regarding HO in patients undergoing cervical TDR, however; and the occurrence of HO and its effects on cervical motion have rarely been reported. Moreover, temporal progression of HO has not been fully addressed. One goal of this study involved determining the incidence of HO following cervical TDR, as identified from plain radiographs, and demonstrating the progression of HO during the follow-up period. A second goal consisted of determining whether segmental motion could be preserved and identifying the relationship between HO and clinical outcomes. The authors conducted a retrospective clinical and radiological study of 28 consecutive patients who underwent cervical TDR with Mobi-C prostheses (LDR Medical) between September 2006 and October 2008. Radiological outcomes were evaluated using lateral dynamic radiographs obtained preoperatively and at 1, 3, 6, 12, and 24 months postoperatively. The occurrence of HO was interpreted on lateral radiographs using the McAfee classification. Cervical range of motion (ROM) was also measured. The visual analog scale (VAS) and Neck Disability Index (NDI) were used to evaluate clinical outcome. The mean follow-up period was 21.6 ± 7.0 months, and the mean occurrence of HO was at 8.0 ± 6.6 months postoperatively. At the last follow-up, 18 (64.3%) of 28 patients had HO: Grade I, 6 patients; Grade II, 8 patients; Grade III, 3 patients; and Grade IV, 1 patient. Heterotopic ossification progression was proportional to the duration of follow-up; HO was present in 3 (10.7%) of 28 patients at 1 month; 7 (25.0%) of 28 patients at 3 months; 11 (42.3%) of 26 patients at 6 months; 15 (62.5%) of 24 patients at 12 months; and 17 (77.3%) of 22 patients at 24 months. Cervical ROM was preserved in Grades I and II HO but was restricted in Grades III and IV HO. Clinical improvement according to the VAS and NDI was not significantly correlated with the occurrence of HO. The overall incidence of HO after cervical TDR was relatively high. Moreover, HO began unexpectedly to appear early after surgery. Heterotopic ossification progression was proportional to the time that had elapsed postoperatively. Grade III or IV HO can restrict the cervical ROM and may lead to spontaneous fusion; however, the occurrence of HO did not affect clinical outcome. The results of this study indicate that a high incidence of HO with the possibility of spontaneous fusion is to be expected during long-term follow-up and should be considered before performing cervical TDR.

Symptomatic heterotopic ossification after very severe traumatic brain injury in 114 patients: Incidence and risk factors

The incidence of heterotopic ossification (HO) among patients with traumatic brain injury (TBI) varies in the literature from 11 to 73.3%. The aim of this study was to determine the incidence of HO among patients with very severe TBI treated in a new established intensive rehabilitation Brain Injury Unit and to list some of the risk-predicting features. The study comprised an approximately complete, consecutive series of 114 adult patients from a well-defined geographical area, and with a posttraumatic amnesia period of at least 28 days, i.e. very severe TBI. Demographic and functional data as well as data about trauma severity and hospital stay of these patients have been registered prospectively in a database (Danish National Head Injury database) at the Brain Injury Unit where the sub acute rehabilitation took place. The present study was based retrospectively on this database, combined with X-rays obtained for symptoms of HO and/or as fracture control. Clinically significant HO was found in 7.9% of the patients. Logistic regression showed an independent significant positive correlation between HO, the female gender and a high Injury Severity Score. The low incidence of HO might be explained by the application of early mobilisation and physiotherapy of the patients. The higher incidence of HO among women speaks for humoural and hormone factors initiating bone formation outside the bones.

Elbow heterotopic ossification in head-trauma patients: diagnosis and treatment.

Heterotopic ossification is a disorder characterized histologically and radiographically by normal bone formation in soft tissues that normally have no ossification properties. In severe head-trauma patients, a high incidence of heterotopic ossification occurs. The diagnosis of this pathology in these patients often is difficult for residual neurological damage. The etiology of heterotopic ossification following head trauma is unknown. Similarities have been found between heterotopic ossification and myositis ossificans, a hereditary autosomal dominant disease.

Heterotopic ossification following uncemented total hip arthroplasty: Effect of the operative approach

A consecutive series of 112 primary uncemented total hip arthroplasties using the same type of prosthesis was reviewed for the incidence and severity of heterotopic ossification (HO). Sixty-three of these patients underwent a posterior approach (group 1) and 49 underwent an anterolateral approach (group 2). The two groups were virtually identical when risk factors, such as age, sex, estimated blood loss, length of surgery, and diagnosis were compared. Patients in group 1 had a significantly lower incidence and severity of HO than those in group 2. The overall incidence of class III or IV HO was very low (8%), indicating that uncemented total hip arthroplasty in itself is not predisposed to moderate or severe degrees of HO. Patients undergoing uncemented total hip arthroplasty through an anterolateral approach had a higher incidence of HO than those undergoing a posterior approach in this series.