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OBJECTIVE To analyze characteristics of surgically managed tear drop (TD) fractures of the C2 axis associated with other injuries such as hangman's fracture and C2-3 discoligamentous injury as well as treatment outcomes. METHODS A total of 14 patients (eight men and six women) with TD fractures of the C2 , who were surgically treated at four national trauma centers of tertiary university hospitals from January 2000 to December 2017, were included in this retrospective study. The mean age of the patients was 45.5 years (ranging from 19 to 74 years). The characteristics, surgical treatment methods (anterior fusion vs posterior fusion), and results of 14 TD fractures of the C2 were analyzed retrospectively. And the clinical relevance between C2 TD fracture and hangman's fracture and C2-3 discoligamentous injury was investigated through the co-occurrence between injuries. The mean follow-up time after surgery was 22.6 months (ranging from 12 to 60 months). RESULTS Among 14 patients with TD fracture of the C2 , four patients (28.6%) had anterior TD fracture and 10 patients (71.4%) had posterior TD fracture. All 10 posterior TD fracture patients had anterior C2-3 displacement. While two of four anterior TD fracture patients had posterior C2-3 displacement, the remaining two did not. All 14 patients of TD fracture had at least two or more other associated C2 injuries as well as C2-3 discoligamentous injuries. About 92.9% (13/14) of the patients had typical or atypical hangman's fracture; 100% (10/10) of the posterior TD fracture patients had hangman's fracture, but 75% (3/4) of the anterior TD fracture had hangman's fracture. At admission, 13 patients were neurologically intact. However, the remaining patient had spinal cord injury with American Spinal Injury Association (ASIA) impairment scale B with C2-3 bilateral facet dislocation. All four anterior TD fracture patients underwent posterior C2-3 fusion. While four of 10 posterior TD fracture patients underwent C2-3 anterior fusion, the remaining six underwent posterior fusion. At last follow-up, 100% (14/14) of the patients achieved solid fusion, and visual analog scale for neck pain was significantly improved (5.9 vs 2.2, P

The objective of this study was to evaluate the survival rates and complications in TKA after UKA and HTO as compared with primary TKA using national health data. It was hypothesized that survival and complication rates would be worse in patients with a history of UKA or HTO compared to primary TKA.Based on a list of patients who underwent TKA from Korean National Health Insurance database, 315,071 underwent primary TKA (group A); 2177 TKA after HTO (group B); and 1284 TKA after UKA (group C). Revision rates were compared between the groups using log-rank tests and adjusted hazard ratios (HR) of groups B and C were compared with those of the reference group (group A). A total of 1000 TKA matched patients were assigned to groups B and C according to propensity score for comparing revision rates after TKA and perioperative complication rates between TKA after HTO and UKA.The overall revision rate was 2.1% in group A, 2.0% in group B, and 4.2% in group C. The revision rate until 10 years after TKA was significantly higher in group B (p = 0.03) or C (p 0.0001) than in group A. The hazard ratios for revision was significantly higher in group A than in groups B and C at 10 years after index TKA (1.4 in group B and 3.7 in group C). The result of the comparison using PSM between TKA after HTO and UKA showed that TKA after HTO had lower risk of revision than TKA after UKA (HR: 0.41 at 10 years). However, no statistically significant differences in the perioperative complication rate between the two groups were found. (NS, not significant) CONCLUSIONS: TKA after UKA or HTO showed a significantly higher risk of revision than primary TKA. While TKA after HTO showed lower risk of revision than TKA after UKA, no significant differences in complications between TKA after UKA and HTO were found. Thus, surgeons must be aware of the low survival rate in TKA after UKA or HTO, especially in TKA after UKA.III (Retrospective cohort study).

Objective To investigate the characteristics of transverse fractures of the C2 axis body diagnosed on sagittal computed tomography (CT) and to propose new classification and appropriate treatment strategies. Methods A retrospective study was performed by enrolling 49 patients (26 men and 23 women) with transverse fractures of the C2 axis body who were treated at four national trauma centers of tertiary university hospitals from January 2000 to December 2017. The mean age of the patients was 60.8 years (ranging from 21 to 90 years). We classified 49 transverse fractures of the C2 body into three types based on fracture trajectories involving superior articular facet (SAF) and lateral cortex (LC) of the C2 body on coronal CT as follows: Type 1, involvement of C2 SAF on both sides; Type 2, unilateral involvement of C2 SAF on one side and LC on the other side; Type 3, involvement of LC on both sides. The characteristics, treatment methods, and results of 49 transverse fractures of the C2 body were analyzed. Mean follow‐up was 12.6 months (ranging from 12 to 26 months). Results Twenty‐six (53.1%) patients were Type 1, 21 (42.9%) were Type 2, and 2 (4.0%) were Type 3. Correlation coefficients for intra‐observer and inter‐observer reliabilities of classification were 0.723 and 0.598 (both, P 3 mm; Incidence of fracture displacement >3 mm was higher in Type 2 than Type 1 (61.9% vs 26.9%, P 3 mm compared to Minerva brace/Halovest (100% vs 0%, P 3 mm., We propose a new radiologic classification for transverse fractures of C2 body and suggest that the majority of transverse fractures of C2 body can be treated conservatively. However, surgery or Minerva brace/Halovest should be considered for Type 2 transverse fractures of the C2 body with fracture displacement >3 mm.

Objective To evaluate the cases of osteoporotic compression fracture with kyphotic deformity treated with modified pedicle subtraction osteotomy and analyze the usefulness of this osteotomy. Methods Twenty patients (nine men, 11 women; mean age, 66.4 years; mean follow-up duration, 39.6 months) who underwent modified pedicle subtraction osteotomy at our hospital between November 2003 and July 2012 with a minimum follow-up period of 2 years were included. All cases were injuries induced by a fall incurred while standing or lifting heavy objects without high-energy trauma. The mean bone mineral density-dual energy x-ray absorptiometry (BMD-DEXA) was 0.673 g/cm2 (0.571-0.740 g/cm2 ), which was -2SD below normal, indicating severe osteoporosis. The indications for surgery included gait disturbance due to severe pain with pseudarthrosis, increased kyphotic angle, and progressive neurological symptoms. We evaluated Japanese Orthopaedic Association scores, Oswestry Disability Index scores, bone union, change in kyphotic angle, estimated blood loss, complications, and the patient's overall clinical satisfaction. Results The collapsed vertebrae were thoracic (T9, 11, 12 ) in 13 cases and lumbar (L1 ) in seven cases. The mean pre- and post-operative kyphotic angles were 26.2 ± 9.9 degrees and 8.3 ± 8.1 degrees, showing an 18.3-degree correction. Plain radiography at the last follow-up showed a mean angle of 17.9 ± 12.6 degrees, indicating a 9.5-degree correction loss. The overall correction was 8.2 degrees. Bony union was achieved at the last follow-up in all cases. Clinical outcomes showed improvement in mean Japanese Orthopaedic Association score from 13.2 to 21.7 and mean Oswestry Disability Index score from 40.3 to 13.6. Overall clinical patient satisfaction showed 12 excellent results, five moderate results, and three poor results. Mean operation time was 4.2 h (range, 4-6 h). The overall mean estimated blood loss (EBL) was 1098 mL (range, 750-1370 mL). The mean hospital stay was 3.6 weeks (range, 2-6 weeks). There was one case of cauda equina syndrome at 2 days postoperatively, and two cases of screw loosening. There were no cases of distal junctional kyphosis, but there were two cases of proximal junctional kyphosis. Conclusions Despite limited correction of kyphotic angle, our modified pedicle subtraction osteotomy technique resulted in satisfactory outcomes in our patients, who had persistent severe back pain, increased kyphotic angle with pseudarthrosis, and progressive neurologic deficits. Nevertheless, this procedure requires careful follow-up and strict surgical indications because of the risk of neurological damage and technical problems.

Spine surgeons often confuse C2 pedicle fractures (PFs) with pars interarticularis fractures. In addition, little information is available about the characteristics and treatment strategies for C2 PFs. We sought to investigate the characteristics of C2 PFs and to propose an appropriate treatment strategy. A total of forty-nine patients with C2 PFs were included in this study. We divided these patients into unilateral and bilateral C2 PF groups. The incidence rates and characteristics of other associated C2 and C2-3 injuries, and other cervical injuries, were evaluated. In addition, treatment methods and outcomes were analyzed. Twenty-two patients had unilateral C2 PFs and twenty-seven patients had bilateral C2 PFs. Among the cases of unilateral C2 PFs, all patients had one or more other C2 fractures, and twenty patients (90.9%) had one or two C2 body fractures. Meanwhile, among the cases of bilateral C2 PF, all patients had two or more other C2 fractures and one or two C2 body fractures. In unilateral C2 PFs, three patients with C2-3 anterior slip or adjacent cervical spine (C1-3) injury underwent surgery and nineteen patients (86.4%) were treated with conservative methods. In bilateral C2 PFs, three patients with C2-3 anterior slip or SCI at C2-3 underwent surgery and twenty-four patients (88.9%) were treated with conservative methods. Our results showed that C2 PFs do not occur alone and are always accompanied by other associated C2 injuries. C2 PFs should, generally, be thought of as a more complex fracture type than hangman’s fracture or dens fracture. Despite the complex fracture characteristics, most C2 PFs can be managed with conservative treatment. However, surgical treatments should be considered if the C2 PFs are accompanied by the C2-3 anterior slip and adjacent cervical spine injury.

Many anterior C2 (2nd cervical vertebra) tear drop (TD) fractures can be successfully managed with conservative treatment. However, due to the occurrence of nonunion, large-sized or complex anterior C2 TD fractures undergo surgical treatment. To date, no surgical treatment guidelines are available about anterior C2 TD fractures. Therefore, we performed this study to investigate the factors that may affect nonunion for anterior C2 TD fractures and to suggest surgical treatment guidelines. Thirty-three patients with anterior C2 TD fractures, who underwent conservative treatment and had a minimum 1-year follow-up, were divided into union (N = 26) and nonunion (N = 7) groups. Their radiological and clinical data were analyzed retrospectively and compared between the two groups. The avulsion fracture ratio (29.5% vs. 43.3%, p &lt, 0.05) and fracture displacement (3.6 mm vs. 5.1 mm, p &lt, 0.05) were higher in the nonunion group compared to the union group. Incidence of associated C2 injury was higher in the nonunion group compared to the union group (15.4% vs. 57.1%, p &lt, 0.05). Union status was negatively correlated with associated C2 injury (correlation coefficient, CC = −0.398, p &lt, 0.05). Our results suggest that surgical treatment could be considered for anterior C2 TD fractures with an avulsion fracture ratio &gt, 43%, fracture displacement &gt, 5 mm, or associated C2 injury.

The cervical spine can be injured even in the absence of radiographic abnormality, and the best surgical treatment for adult spinal cord injury without bone injury is debated. The aim of this study was to retrospectively investigate the effect of surgical decompression for severe adult spinal cord injury without major bone injury and to establish predictors of good neurological outcome. We analyzed 11 patients who underwent surgical decompression in severe adult spinal cord injury without major bone injury patients classified as American Spinal Injury Association Impairment Scale (AIS) grade A, B, or C. Neurological assessments were performed using AIS at preoperative and postoperative 1-year follow-up. Radiological evaluations were performed using cervical magnetic resonance imaging (MRI) at preoperative. Seven cases were classified as AIS grade A, two cases as AIS grade B, and two cases as AIS grade C. Five of 11 (45.5%) patients showed improved neurological grade 1-year postoperatively. Intramedullary lesion length (IMLL) (p = 0.047) and compression rate (p = 0.045) had the most powerful effect on AIS grade conversion. This study shows that the fate of the injured spinal cord is determined at the time of the injury, but adequate decompression may have limited contribution to the recovery of neurological function. Compression rate and IMLL on MRI can be used as a predictor of neurological recovery.

Highly displaced Hangman's fracture is a very rare and extremely unstable fracture of the C2 axis. Combined anteroposterior or posterior long-segment fusion surgery is typically performed for the treatment of highly displaced Hangman's fracture. However, these kinds of surgeries increase the risk of complications, loss of motion, and hospital costs.We sought to investigate the surgical outcomes of anterior C2-3 fusion surgery alone for highly displaced Hangman's fractures with severe angulation of C2-3 by more than 30° and discoligamentous injury.A total of five patients (four men and one woman) were included in this study with a mean age of 40.4 years (range, 26-70 years). The mean follow-up period after surgery was 37.2 months (range, 12-96 months). The fracture characteristics, treatment methods, and outcomes were retrospectively analyzed.All five patients had type II Hangman's fractures (according to the Levine and Edwards classification scheme). None of the included patients had neurologic deficit or other spine injury but all patients had complete C2-3 discoligamentous injury. Before surgery, all patients successfully achieved closed reduction by skull traction, followed by C2-3 anterior decompression and fusion (ACDF) with plating. For interbody grafting, three patients received a polyetheretherketone (PEEK) cage filled with an autogenous cancellous iliac bone graft and two received autogenous tricortical iliac bone grafts. Severe angulation (39.2° vs. 3.0°, P 0.001) and severe displacement (76.1% vs. 4.0%, P 0.001) of C2-3 were both significantly corrected after surgery. All patients had achieved solid fusion at last follow-up. In terms of clinical outcomes, the mean neck pain visual analog scale score was significantly improved (8.6 points vs. 1.8 points, P 0.001). The mean neck disability index value was also significantly improved (45.4 points vs. 13.0 points, P 0.01). According to Odom's criteria, all patients achieved satisfactory outcomes. No major complications occurred. One patient complained of dysphagia, but recovered after three months with conservative treatment.Preoperative closed reduction and anterior C2-3 fusion surgery alone should be considered as a less-invasive and useful surgical option for highly displaced Hangman's fracture with severe angulation of C2-3, which is an extremely unstable fracture of the C2 axis.

Rationale: A case of traumatic atlanto-axial rotatory subluxation (AARS), dens fracture, rupture of transverse atlantal ligament (TAL), and subaxial spinal cord injury without radiographic abnormality (SCIWORA) of Brown-Sequard syndrome has never been reported in a child. Patient concerns: A 7-year-old boy presented to hospital with torticollis, neck pain, and limited neck rotation after a seat-belt injury sustained during a car accident. Neurologic examination revealed right-side motor weakness and left-side sensory abnormality, known as Brown-Sequard syndrome. Diagnosis: Radiologic examinations revealed type II AARS (Fielding and Hawkins classification), increased atlanto-dental interval (ADI) of 4.5 mm due to a type 1B TAL rupture (Dickman classification), a displaced transverse dens fracture along with an ossiculum terminale, and an intramedullary hemorrhage on the right side of the spinal cord at C3–4. Interventions: The patient immediately received methylprednisolone, and his motor weakness and sensory abnormality gradually improved. At the same time, the patient underwent initial halter traction for 2 weeks, but he failed to achieve successful reduction and required manual reduction under general anesthesia. Outcomes: At the 7-month follow-up visit, radiologic examinations showed a corrected type II AARS that was well maintained and normalization of the ADI to 2 mm. The reduced transverse dens fracture was well maintained but still not united. All clinical symptoms were significantly improved, except the remaining motor weakness of the right upper extremity. Lessons: To the best of our knowledge, this is the first report of traumatic AARS, dens fracture, TAL rupture, and subaxial SCIWORA of Brown-Sequard syndrome in a child. Appropriate diagnosis and careful treatment strategy are required for successful management of complex cervical injuries in a child.

Background:Residual rotational instability after isolated anterior cruciate ligament reconstruction (ACLR) has been a challenge for many years. Anterolateral extra-articular procedures (AEAPs), including anterolateral ligament reconstruction (ALLR) or lateral extra-articular tenodesis (LET), are performed as a surgical option for additional rotational stability, but clear evidence for their usefulness is lacking.Purpose:To conduct a systematic review and meta-analysis of the literature regarding the efficacy of AEAP in primary ACLR.Study Design:Systematic review; Level of evidence, 3.Methods:A literature search, data extraction, and quality assessment were conducted by 2 independent reviewers. MEDLINE, EMBASE, and the Cochrane Library were searched in April 2020, following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A total of 3444 studies were screened, and 20 studies (11 randomized controlled trials and 9 nonrandomized studies) were evaluated. Functional outcomes, stability, and complications were compared between patients who underwent primary ACLR with AEAP and those who underwent isolated primary ACLR. For subgroup analysis, outcomes were compared according to AEAP technique (ALLR vs LET) and time from injury to surgery (≤12 vs >12 months). The methodological quality of the included studies was assessed using the Cochrane risk-of-bias tool, Jadad scale, and Newcastle-Ottawa Scale.Results:Compared with isolated ACLR, combined ACLR with AEAP led to improved pivot-shift grades and graft failure rates, regardless of the AEAP technique or of time from injury to surgery. A limited, marginal improvement in subjective function score was observed in patients who underwent AEAP combined with ACLR. In contrast to ALLR, patients who underwent LET combined with ACLR had an increased risk of knee stiffness and adverse events.Conclusion:Our review suggests that when there is a need to improve rotational stability and subjective function, AEAP combined with primary ACLR can be considered regardless of time from injury. ALLR appeared to be a better option for improving rotational stability compared with LET.

Background: Modern total ankle arthroplasty (TAA) prostheses are uncemented press-fit designs whose stability is dependent on bone ingrowth. Preoperative insufficient bone density reduces initial local stability at the bone-implant interface, and we hypothesized that this may play a role in periprosthetic osteolysis. We aimed to investigate the preoperative bone density of the distal tibia and talus and compare these in patients with and without osteolysis. Methods: We enrolled 209 patients (218 ankles) who underwent primary TAA using the HINTEGRA prosthesis. The overall mean follow-up duration was 66 (range, 24-161) months. The patients were allocated into 2 groups according to the presence of periprosthetic osteolysis: the osteolysis group (64 patients, 65 ankles) and nonosteolysis group (145 patients, 153 ankles). Between the 2 groups, we investigated and compared the radiographic outcomes, including the Hounsfield unit (HU) value around the ankle joint and the coronal plane alignment. Results: HU values of the tibia and talus measured at 5 mm from the reference points were higher than those at 10 mm in each group. However, comparing the osteolysis and nonosteolysis groups, we found no significant intergroup difference in HU value at every measured level in the tibia and talus ( P > .05). Concerning the coronal plane alignment, there were no significant between-group differences in the tibiotalar and talar tilt angles ( P > .05). Conclusion: Patients with osteolysis showed similar preoperative bone density of the distal tibia and talus compared with patients without osteolysis. Our results suggest that low bone density around the ankle joint may not be associated with increased development of osteolysis. Level of Evidence: Level III, retrospective cohort study.

Transpedicular screw instrumentation systems have been increasingly utilized during the fusion of lumbar spine procedures. The superior segment facet joint violation of the pedicle screw is thought to have potential for accelerating symptomatic adjacent-segment pathology (ASP). The purpose of this study was to investigate the relationship between the superior segment facet joint violation by transpedicular screws and the development of ASP. Among all patients who underwent operations involving one- or two-level posterior lumbar arthrodesis at the Chonnam National University Hospital from 1992 to 2012, 87 patients were selected for this study. Fifty-six patients were included in the ASP group, and 31 were included in the non-ASP group. We used lumbar three-dimensional computed tomography (CT) to assess the violation of the superior facet joint by a transpedicular screw. The assessment is presented in scores ranging from zero to two, with zero indicating no violation (type I), one point indicating suspected violation (type II), and two points indicating definitely facet joint violation (type III). Facet violation was reported in 31 patients in the ASP group (n = 56), and in 13 patients in the non-ASP group (n = 31). The types of facet joint violation according to our scoring system were as follows: type I, 59 screws (52.7%), type II, 26 screws (23.2%), and type III, 27 screws (24.1%) in the ASP group, and type I, 43 screws (69.4%), type II, 14 screws (22.6 %), and type III, 5 screws (8.0%) in the non-ASP group. The score of facet joint violation in each patient according to our scoring system were as follows: 0 points, 25 patients (44.6%), 1 point, 8 patients (14.3%), 2 points, 4 patients (7.1%), 3 points, 11 patients (19.7%), 4 points, 8 patients (14.3%) in the ASP group, and 0 points, 18 patients (58.1%), 1 point, 4 patients (12.9%), 2 points, 7 patients (22.6%), 3 points, 2 patients (6.4%), 4 points, 0 patients (0%) in the non-ASP group. The mean scores were 1.4 points in the ASP group and 0.8 points in the non-ASP group (p &lt, 0.05). We conclude that the position of the pedicle screw farther away from the facet joint surface can reduce the degeneration of the superior adjacent segment. Therefore, close attention to the screw position during surgery may reduce the rate of superior adjacent-segment pathologies.

Background Various methods such as laminectomy, laminoplasty, and/or laminotomy can be used to remove intraspinal lesions. However, laminoplasty has generally been known to be able to prevent postoperative instability and deformity and avoid local scarring at operative site. We have described a new laminoplasty technique that can preserve the interspinous ligament during thoracolumbar intraspinal surgery. Methods Ten patients undergoing laminoplastic tumor excision were evaluated preoperatively and postoperatively with neurologic examinations, a pain visual analog scale, and the Oswestry Disability Index. Instability and fusion were evaluated with plain radiography and computed tomography. The operative time, complications, and hospital stay were also assessed. Results We assessed the data from 10 patients (12 disc levels) with intradural extramedullary tumor who had undergone a ligament-saving laminoplasty procedure. Of the 10 tumors, 6 were schwannoma, 2 were meningioma, 1 was extra-adrenal paraganglioma, and 1 was metastatic adenocarcinoma. Spinal computed tomography was performed 6 months postoperatively. Complete union of the laminoplasty site was achieved for all 10 patients. The flexion-extension view of the plain radiograph was compared with the preoperative images to evaluate the stability of the operated level. No patient had range of motion limitation or instability. Conclusions Ligament-saving laminoplasty can provide an appropriate surgical view and allow for anatomical reconstruction of the spinal posterior element after excision of spinal cord tumors. This procedure might offer an alternative to classic techniques for selected patients to preserve spinal biomechanical function.

Rationale Traumatic atlantoaxial anteroinferior subluxation associated with a dens fracture and a Hangman fracture is a very rare and complex injury. Therefore, appropriate surgical strategy is not established. Patient concerns An 85-year-old female presented with posterior neck pain and atypical neck position caused after rolling down a hill. Although neurological examinations for motor, sensory, gait, and reflex tests were normal, the patient complained of an abnormal neck posture. Diagnoses Radiological examinations revealed an atlantoaxial anteroinferior subluxation with kyphosis, a type IIA dens fracture (Anderson and D'Alonzo classification) with an anterolateral rotatory angulation of type IIA dens fracture fragment, and a type I Hangman fracture (Levine and Edwards classification). Nevertheless, the transverse atlantal ligament was intact. Interventions We considered that the intact transverse atlantal ligament and kinking of the type IIA dens fracture fragment into the left lateral mass of C1 prevented a spinal cord injury by blocking a further displacement of C1 to C2. Due to the patient's osteoporosis and the anterolateral rotatory angulated type IIA dens fracture fragment, a forceful reduction of the atlantoaxial anteroinferior subluxation with kyphosis could pose a high risk of fixation failure and spinal cord injury. Therefore, we performed in-situ posterior C1-2 fusion using a C1 lateral mass screw and C2 lamina screw fixations. Outcomes At 1 year after surgery, the bone union of all fractures was achieved in the kyphosis state. Furthermore, the patient's clinical symptoms were improved with no neurological deficit. Lessons A thorough radiological examination and appropriate surgical strategy are important for successful diagnosis and treatment of a complex C1-2 injury.

Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion.

Background Context Many complications of lumbar fusion have been reported. However, reports of complications related to implant removal after solid fusion are rare. In addition, there are almost no reports of compression fractures occurring within a fusion mass. Purpose This work aimed to report a case of vertebral body compression fracture within a solid lumbar fusion mass after removal of fusion instrumentation, and to investigate the contributing factors. Study Design A case report was carried out. Methods A 67-year-old woman presented with gait disturbance and pain radiating from both lower extremities. She had a history of lumbar fusion at L2–L5 because of degenerative stenosis. We found spinal stenosis at L5–S1 and ossification of the ligamentum flavum at T12–L2. Posterior decompression and fusion were performed for the lesion, and previously inserted fusion instrumentation was removed at L2–L5 in accordance with the patient's request. After surgery, her symptoms decreased and she was discharged. Five weeks after surgery, the patient returned with sudden, severe back pain that occurred without trauma. Compression fracture at the L3 lower end plate was observed via magnetic resonance imaging. We treated her back pain with analgesics and a thoracolumbosacral orthosis. After 2 weeks, her back pain had decreased, and she was discharged. Results Before removal of instrumentation, we verified complete union using computed tomography. However, an unexpected compression fracture occurred within the fusion mass, without trauma. We suspect that the causes of the compression fracture were the straight sagittal imbalance of the spine, the cantilever motion in the anterior disc after posterior fusion, and decreased bone strength. Conclusions Vertebral compression fracture in a solid fusion mass may occur as a complication of implant removal. Surgeons must take care to maintain normal sagittal alignment during spinal fusion, and they should consider careful removal of instrumentation for patients with risk factors such as osteoporosis, sagittal imbalance, long spine fusion, and certain types of fusion.

Gas-containing pseudocysts in the spine are a rare cause of radicular pain [1–5]. It has been suggested that they are associated with the intervertebral vacuum phenomenon [6]. Until now, most symptomatic gas-containing pseudocysts have been found within the confines of the spinal canal. However, a gas-containing pseudocyst located in the extraforaminal zone causing radicular compression is very rare [4], and it is underestimated and untreated in many cases. Therefore, we present a case that required surgery due to an extraforaminal gas-containing pseudocyst at the L3–4 and L4–5 disc levels and discuss the relevant literature.

Background The purpose of this study was to determine whether restoration of range of motion (ROM) could be achieved by implant removal after natural bone healing and consolidation of fractured vertebrae and examine whether early removal of the implant could maximize restoration of ROM. Methods This study included 30 cases of thoracolumbar fractures without neurological deficit requiring surgery (nine cases of flexion-distraction injuries and 21 cases of burst fractures). Percutaneous pedicle screw fixation (PPSF) was performed at the fractured vertebrae and one level above and one level below the fracture level. Pedicle screws were removed at an average of 12 months after surgery upon healing of fractured vertebrae. The following radiological and clinical findings were evaluated: restoration of anterior vertebral height ratio (AVHR), Cobb angle (CA), ROM, and complications. Sixteen patients who were checked for ROM were divided into two groups based on the time of implant removal: nine patients within 12 months and seven patients after 12 months. Restoration of vertebral height loss and ROM were compared between the two groups. Results At the final follow-up, significant pain relief and restoration of AVHR and CA were achieved in patients who underwent PPSF. Patients who had implant removed within 12 months after surgery had better ROM recovery than those who had implant removed after 12 months postoperatively. There were no significant differences in AVHR and CA between the two groups. Conclusions PPSF followed by implant removal after healing of fractured body appears to be effective in achieving restoration of ROM. In our study, early removal of implant within 12 months after surgery was associated with better achievement of ROM than removal after 12 months. In addition, there were no significant differences in restoration of vertebral height between the two groups.

Background: Pedicle screws are being used commonly in the treatment of various spinal disorders. However, use of pedicle screws in the pediatric population is not routinely recommended because of the risk of complications. The present study was to evaluate the safety of pedicle screws placed in children aged less than 10 years with spinal deformities and to determine the accuracy and complication (early and late) of pedicle screw placement using the postoperative computed tomography (CT) scans. Materials and Methods: Thirty one patients (11 males and 20 females) who underwent 261 pedicle screw fixations (177 in thoracic vertebrae and 84 in lumbar vertebrae) for a variety of pediatric spinal deformities at a single institution were included in the study. The average age of patients was 7 years and 10 months. These patients underwent postoperative CT scan which was assessed by two independent observers (spine surgeons) not involved in the treatment. Results: Breach rate was 5.4% (14/261 screws) for all pedicles. Of the 177 screws placed in the thoracic spine, 13 (7.3%) had breached the pedicle, that is 92.7% of the screws were accurately placed within pedicles. Seven screws (4%) had breached the medial pedicle wall, 4 screws (2.3%) had breached the lateral pedicle wall and 2 screws (1.1%) had breached the superior or inferior pedicle wall respectively. Of the 84 screws placed in the lumbar spine, 83 (98.8%) screws were accurately placed within the pedicle. Only 1 screw (1.2%) was found to be laterally displaced. In addition, the breach rate was found to be 4.2% (11/261 screws) with respect to the vertebral bodies. No neurological, vascular or visceral complications were encountered. Conclusions: The accuracy of pedicle screw placement in pedicles and vertebral bodies were 94.6% and 95.8% respectively and there was no complication related to screw placement noted until the last followup. These results suggest that free-hand pedicle screw fixation can be safely used in patients younger than 10 years to treat a variety of spinal disorders.

STUDY DESIGN Retrospective chart review. PURPOSE To assess whether spontaneous reduction of spondylolisthesis, as seen on magnetic resonance imaging (MRI), is related to the degree of segmental instability and low back pain. OVERVIEW OF LITERATURE The flexion-extension radiographs obtained in the sagittal plane are frequently used when segmental instability of spondylolisthesis is evaluated. METHODS We retrospectively reviewed 137 patients and measured the differences of the percentage of sagittal translation and sagittal angulation to determine the segmental instability between the flexion and extension radiographs, and the spontaneous reduction on MRI. We then compared the degrees of segmental instability and the degrees of spontaneous reduction. To assess the effect of low back pain on segmental motion in regards to the flexion-extension radiographs, we compared the preoperative visual analogue scales (VAS) score for low back pain between the more and the less spontaneous reduction groups. RESULTS The mean degree of spontaneous reduction was 5.2%. A statistically significant correlation was found between the sagittal translation on the flexion-extension radiographs and the degree of spontaneous reduction (r = 0.557, p < 0.001) and between the sagittal angulation on the flexion-extension radiographs and the degree of spontaneous reduction (r = 0.215, p = 0.012). The preoperative VAS scores for low back pain of the more spontaneous reduction group and the less spontaneous reduction group were 4.6 and 3.6 points, respectively, and this difference was statistically significant (p = 0.002). CONCLUSIONS Spontaneous reduction of spondylolisthesis on MRI was found to be closely related to segmental instability, and the degree of spontaneous reduction seen on MRI could be useful for the evaluation of segmental instability in patients with spondylolisthesis, especially with severe low back pain.

The effects of different femoral component designs on intraoperative range of motion were examined in 40 female patients during primary cruciate-retaining (CR) total knee arthroplasty. After complete bone resection and soft tissue balancing, standard CR, high-flexion, and gender-specific knee trials were sequentially inserted, and maximal flexion and extension under gravity were measured using a navigation system. Average maximal flexions were 134.3° for standard CR knees, 136.2° for high-flexion knees, and 136.4° for gender-specific knees. No significant intergroup differences in intraoperative maximal flexion and extension were found (P > .05). High-flexion and gender-specific femoral designs were found to show subtle increases in intraoperative range of motion as compared with the standard design but no significant differences.

Background: Several biomechanical studies have supported placing the femoral tunnel at a low position (10 or 2 o’clock) to achieve anterior and rotational knee stabilities after anterior cruciate ligament (ACL) reconstruction. However, no firm consensus has been reached regarding the merits and demerits of ACL reconstruction using a low femoral tunnel versus a high femoral tunnel (11 or 1 o’clock).Hypothesis: A low femoral tunnel position during ACL reconstruction provides better intraoperative stability (especially, rotational stability) and clinical outcomes than does a high femoral tunnel position.Study Design: Cohort study; Level of evidence 2.Methods: Sixty-two patients who underwent ACL reconstruction were equally allocated to low and high femoral tunnel groups; 58 were followed up for a minimum of 2 years (29 in the each group). After reconstruction and using a navigation system, the authors compared intraoperative anterior, internal rotational, and external rotational stabilities at 0°, 30°, 60°, and 90° of knee flexion and compared clinical outcomes, including Lysholm knee scores, Tegner activity scores, Lachman and pivot-shift test findings, and radiographic stabilities at final follow-up visits.Results: The low group showed significantly better intraoperative internal rotational stability at 0° and 30° of flexion but not at other angles (60° and 90°). Intraoperatively, no significant intergroup differences were found for anterior and external rotational stabilities at any flexion angle. Furthermore, clinical outcomes, including Lysholm knee and Tegner activity scores, showed no significant differences between the 2 groups at final follow-up visits ( P > .05), and Lachman and pivot-shift test stability results and radiological stability data obtained at final follow-up were not significantly different between the 2 groups ( P > .05).Conclusion: The low femoral tunnel group showed better internal rotational stability at time zero during ACL reconstruction but similar anterior and external rotational stabilities. No significant differences were observed between the 2 groups in terms of clinical outcomes and stabilities after a minimum follow-up of 2 years.

BACKGROUND CONTEXT Although there were many studies about the application of the TLICS classification to thoracolumbar spine injuries, large-scale studies of efficacy in treated patients were rarely investigated. PURPOSE This study aimed to assess the efficacy of TLICS classification in the selection of treatment methods for patients with thoracolumbar spine injury. METHODS From 2000 to 2016, we retrospectively studied 330 patients who were treated for thoracolumbar spine injuries. Clinical results and radiological data were studied and analyzed using ASIA scale, Magerl/AO classification and TLICS classification. RESULTS Among 330 patients, 139 patients (42.1%) received conservative treatment and 191 patients (57.9%) received surgical treatment. Of the 139 patients who underwent conservative treatment, 128 patients (92.1%) were consistent with the recommended treatment in TLICS. Of the patients who underwent conservative treatment, 10 patients (7.2%) failed conservative treatment and required surgical treatment. On the other hand, out of a total of 191 patients who underwent surgical treatment, 160 patients (83.8%) were consistent with the recommended treatment in TLICS. CONCLUSIONS The TLICS classification is highly effective in the conservative treatment of thoracolumbar junction injury. In addition, it has relatively good efficacy in surgical treatment

Background In patients who need sustained endotracheal intubation and mechanical ventilation due to respiratory failure after traumatic cervical spinal cord injury, tracheostomy can be performed to reduce the duration of mechanical ventilation and respiratory complications. The purpose of this study was to determine criteria and timing of tracheostomy in patients with severe traumatic cervical spinal cord injury accompanied by motor weakness. Methods We reviewed 22 patients who underwent tracheostomy (study group) and 27 patients who did not (control group) from January 2005 to March 2016. We assessed the American Spinal Injury Association (ASIA) impairment scale score and investigated accompanying thoracic injury, paradoxical respiration, postoperative endotracheal intubation and other clinical parameters. The study group was also subdivided into the early tracheostomy group and late tracheostomy group depending on whether the tracheostomy was performed within or later than 7 days after surgery. Results Twenty-two patients in the study group had a mean ASIA impairment scale score of 14.1 points, which was lower than the control group's 23.4 points. Paradoxical respiration was observed in 77% of the patients in the study group compared to 18% in the control group. Postoperative intubation was maintained in 68% in the study group; 32% underwent endotracheal intubation due to respiratory failure within 4 days after surgery and had a tracheostomy. In the control group, postoperative intubation was maintained in 22%, and all of them were weaned off intubation within 4 days after surgery. The duration of intensive care unit hospitalization was 11.4 days for the early tracheostomy group, which was shorter than the late tracheostomy group's 19.7 days. Conclusions In patients with severe traumatic cervical spinal cord injury, tracheostomy may be needed when the motor grade of the ASIA scale is low, above the C4 segment is injured, or paradoxical respiration occurs after injuries. In addition, if endotracheal extubation is not feasible within 4 days after surgery, an early tracheostomy should be considered.

This study aimed to assess the feasibility of bilateral simultaneous minimally invasive two-incision total hip arthroplasty in terms of clinical and radiological outcomes, complications, and patient satisfaction.A total of 62 patients, ages 24-69 years, were operated on with bilateral simultaneous minimally invasive total hip arthroplasty using a modified two-incision technique, after which they were followed for an average 41 months. The acetabular component was inserted through part of the Watson-Jones approach, and a femoral component was inserted through a space between the gluteus medius and piriformis tendon.The mean duration of surgery was 180.4 min, and the mean perioperative blood loss was 1513.2 ml. There were no intraoperative complications. Postoperative periprosthetic fracture occurred in two patients and delayed infection in one patient. The average Harris Hip Score improved from 41.8 to 95.3. The WOMAC score improved from an average of 66.2 to 5.0. The average lateral opening angle of the acetabulum was 40 degrees , and the angle of anteversion was 12 degrees . All the femoral components were implanted in neutral to 5 degrees valgus position.Bilateral simultaneous minimally invasive total hip arthroplasty using a modified two-incision technique gave satisfactory clinical, radiological, and functional results. Efforts should be made to prevent perioperative periprosthetic fractures.

There has been increasing interest in performing total hip arthroplasty (THA) with minimally invasive surgery (MIS). This study was conducted to examine the effectiveness of MIS-THA using the new two-incision technique versus the one-incision technique. A consecutive series of 113 patients who underwent MIS-THAs (63 one-incision cases, 50 two-incision cases) were studied. One-incision THA was performed with a posterolateral approach. For the two-incision, the first incision for cup insertion was made over the anterolateral side of the hip. Intermuscular dissection was performed between the gluteus medius and the tensor fascia lata. The second incision, for stem insertion, was made on the posterolateral side of the hip along the fiber of the gluteus maximus. Intermuscular dissection was made between the gluteus medius and the piriformis. Postoperative rehabilitation was significantly more rapid in the new two-incision group compared to the group with one incision. Postoperatively, the Harris Hip Score and the Western Ontario and the McMaster Universities Osteoarthritis Index score were significantly different between the two groups, especially the functional sections. The findings of this study show that our new two-incision MIS-THA is an excellent surgical modality that allows early rehabilitation.

The purpose of this study was to evaluate the intra-operative stability during double-bundle anterior cruciate ligament (ACL) reconstructions (20 knees) using a navigation system and compare the results with those obtained from single-bundle reconstructions (20 knees). After registering the reference points during ACL reconstruction, antero-posterior and rotational stability tests with 30 degrees knee flexion using a navigation system were measured before and after reconstructions on both groups. The change of antero-posterior translation after and before reconstruction was 12.5 mm in the double-bundle group and 10.5 mm in the single-bundle group, showing significant inter-group difference (p=0.014, from 17.5 mm to 5.1 mm in the double-bundle and from 16.6 mm to 6.1 mm in the single-bundle group). The mean rotational stability of the double-bundle group also showed more significant improvement after reconstruction compared to that of the single-bundle group (9.8 degrees in the double- and 5.6 degrees in the single-bundle groups, p0.001). These findings suggest that a double-bundle ACL reconstruction restores greater knee stability with respect to the antero-posterior and rotational stability than a single-bundle reconstruction.

In Legg-Calvé-Perthes disease (LCPD), 4 major patterns (coxa plana, coxa magna, coxa vara, subluxation) of the femoral head are commonly observed. However, direct observation of pathological specimens is rarely possible. An animal model of LCPD may clarify the pathogenesis of femoral head deformity.In 26 piglets, we interrupted the vascular supply to the capital femoral epiphysis by cutting the ligamentum teres and ligating the femoral neck containing the epiphyseal artery. 6-7 piglets in each experimental group were killed at early (2 and 4 weeks: P2 and P4), intermediate (12 weeks: P12), and late (20 weeks: P20) periods. We examined the extracted femoral heads macroscopically and radiographically.The mean decrease in epiphyseal height was 1.5 mm, 4.1 mm, 5.0 mm, and 7.5 mm in P2, P4, P12 and P20, respectively (rs = 0.76, p = 0.002). The mean increase of diameter was 4.1 mm, 6.9 mm, and 6.8 mm in P4, P12 and P20, respectively. Decrease of the articulotrochanteric distance was mild in P2 and P4, and severe in P12 and P20. Subluxation of the femoral head was observed only in P12 and P20 piglets.The piglet model of LCPD was useful in the early stage of devascularization for investigation of the developmental pattern of femoral head deformity. However, when the piglets had grown to 20 weeks old or more--that is, to full skeletal maturity--the femoral head and acetabulum showed severe deformities that were most likely caused by heavy body weight.

The purpose of this study was to evaluate the results of liner cementation into a stable acetabular shell using a metal-inlay polyethylene liner in 39 revision total hip arthroplasties. After an average of 2.8 years, 1 cemented liner dislodged from its metal shell at a postoperative 4 years. In the other 38 hips, mean Harris hip scores improved from 65 preoperatively to 86.9 at the final follow-up. Eighteen patients were rated as having excellent results, 17 as good, and 3 as fair. There were no changes in cup position and no cases of osteolytic lesion progression around the femoral and acetabular components in the last follow-up radiographs. Metal-inlay polyethylene liner cementation into a stable acetabular shell was found to provide an alternative option with short-term excellent results, and it also offers more liner options, the preservation of bone stock, and lower surgical morbidity.

Theoretically, the motion of a bipolar hip prosthesis is most likely to occur at the inner joint if the frictional coefficients are equal at both surfaces. However, many studies have suggested that most motion occurs at the outer joint.We performed an analysis of motion in a cadaveric bone model and in 50 patients during fluoroscopic examination, to determine how the motion is distributed between the two joints and what factors contribute to this distribution.The motion distributions varied widely between the patients. However, there was a relative pre-ponderance (63-90%) of outer motion in all directions of leg movement in addition to a persistent coexistence of motion at both joints in 44 of 50 patients. This preponderance of outer motion was the result of an early impingement of the acetabular cup and structural differences between the two joints.An adjustment of the positive eccentricity and a decrease in the frictional torque of the inner joint as a result of better lubrication and smoothness can be expected to improve the motion distribution, thus reducing the amount of acetabular erosion.

Malunion of femoral head fractures has been rarely reported. We report on three cases of malunion of the femoral head, which were treated by partial ostectomy. All patients were involved in traffic accidents and had a posterior fracture-dislocation of the hip. The types of femoral head fractures were Pipkin type I with inferomedial fracture fragment in all cases. Initially, they were treated by closed reduction and skeletal traction for between 6 and 8 weeks. The patients were then transferred to our hospital; the chief complaint was of limited hip motion. A protruding bony mass limiting the hip motion was resected in all cases. The Smith-Petersen approach was used in all cases. The malunion sites were located distally to the original fracture site in all cases. Full weight bearing was permitted, and a range of motion exercises was started postoperatively. Excellent results were obtained with almost complete restoration of hip motion without pain. In the follow-up radiographs, there were no cases of avascular necrosis.

Background:It is still debated whether a degenerative horizontal tear of the medial meniscus should be treated with surgery.Hypothesis:The clinical outcomes of arthroscopic meniscectomy will be better than those of nonoperative treatment for a degenerative horizontal tear of the medial meniscus.Study Design:Randomized controlled trial; Level of evidence, 1.Methods:A total of 102 patients with knee pain and a degenerative horizontal tear of the posterior horn of the medial meniscus on magnetic resonance imaging were included in this study between January 2007 and July 2009. The study included 81 female and 21 male patients with an average age of 53.8 years (range, 43-62 years). Fifty patients underwent arthroscopic meniscectomy (meniscectomy group), and 52 patients underwent nonoperative treatment with strengthening exercises (nonoperative group). Functional outcomes were compared using a visual analog scale (VAS) for pain, Lysholm knee score, Tegner activity scale, and patient subjective knee pain and satisfaction. Radiological evaluations were performed using the Kellgren-Lawrence classification to evaluate osteoarthritic changes.Results:In terms of clinical outcomes, meniscectomy did not provide better functional improvement than nonoperative treatment. At the final follow-up, the average VAS scores were 1.8 (range, 1-5) in the meniscectomy group and 1.7 (range, 1-4) in the nonoperative group ( P = .675). The average Lysholm knee scores at 2-year follow-up were 83.2 (range, 52-100) and 84.3 (range, 58-100) in the meniscectomy and nonoperative groups, respectively ( P = .237). In addition, the average Tegner activity scale and subjective satisfaction scores were not significantly different between the 2 groups. Although most patients initially had intense knee pain with mechanical symptoms, both groups reported a relief in knee pain, improved knee function, and a high level of satisfaction with treatment ( P < .05 for all values). Two patients in the meniscectomy group and 3 in the nonoperative group with Kellgren-Lawrence grade 1 progressed to grade 2 at the 2-year follow-up.Conclusion:There were no significant differences between arthroscopic meniscectomy and nonoperative management with strengthening exercises in terms of relief in knee pain, improved knee function, or increased satisfaction in patients after 2 years of follow-up.

We report a case of extensive subcutaneous emphysema of the lower extremity mimicking gas gangrene following perforation of the rectum in a 38-yr-old man. Subcutaneous emphysema of the leg may rarely occur secondary to perforation of the gastrointestinal tract and has often created serious diagnostic problems and high mortality rates. Therefore, prompt diagnosis and aggressive treatment is imperative.

The purpose of this study was to compare clinical outcomes including return to recreational activities (cycling, swimming, exercise walking, dancing, jogging, and mountain climbing) after opening-wedge high tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA). Clinical outcomes were assessed using Tegner activity scores, ranges of motion, and Lysholm knee scores. In both groups, the number of patients participating in recreational activities was significantly reduced after surgery, but without a significant intergroup difference (1.3 activities in HTO group and in 1.6 activities in UKA group). Average Tegner activity scale scores, ranges of motion, and Lysholm knee scores did not show significant differences between the 2 groups. This study identified no significant differences between HTO and UKA for medial unicompartmental osteoarthritis in terms of return to recreational activity and short-term clinical outcomes.

Purpose The purpose of this study was to compare the clinical and radiographic outcomes of opening- and closing-wedge valgus high tibial osteotomy (HTO) for the treatment of medial unicompartmental knee osteoarthritis with a minimum follow-up of 3 years, with a focus on patellofemoral alignment and anterior knee pain. Methods We performed a retrospective comparison of 50 patients who underwent closing-wedge HTO and 50 patients who underwent opening-wedge HTO for isolated medial joint arthritis of the knee with varus deformity. All patients were evaluated and the 2 study groups were compared after a minimum follow-up of 3 years with a focus on patellofemoral alignment, patellofemoral osteoarthritis, and anterior knee pain while climbing stairs. Results Patellar alignment (patellar tilt and lateral patellar displacement) was not significantly different in the 2 groups either preoperatively or at follow-up. Furthermore, there were no significant differences in the extent of patellofemoral arthritis and incidence of anterior knee pain at follow-up between the 2 groups. In addition, no significant intergroup difference was found in terms of the incidence of anterior knee pain (28% in closing-wedge group and 32% in opening-wedge group at follow-up). Conclusions The results of closing- and opening-wedge valgus HTO were not found to be significantly different with respect to patellar alignment, osteoarthritis of the patellofemoral joint, or anterior knee pain. Level of Evidence Level III, retrospective comparative study.

In polyostotic fibrous dysplasia, particularly in lesions of the proximal femur, pathological fracture and coxa vara deformity (including shepherd's crook deformity) are likely to develop and progress.In 7 femurs with shepherd's crook deformity (5 patients), we performed intramedullary nailing by using multiple osteotomies and two screws crossing the femoral neck.Restoration of the neck shaft angle of the femur was obtained from an average of 92 degrees prior to surgery to 129 degrees after surgery. During the minimum 2-year follow up, no loss of neck shaft angle of the femur and no refracture occurred. All patients were able to return to normal activities of daily living.In polyostotic fibrous dysplasia, multiple osteotomies and intramedullary nailing with neck cross-pinning can be used to correct developed or progressing shepherd's crook deformity, and to prevent recurrence and refracture.

Although the incidence of pulmonary embolism (PE) following arthroscopic knee surgery has not been well established, such occurrences place the patient at high risk. In this report we present a case of PE following arthroscopic meniscectomy. The patient was a 63-year-old woman, with no definite risk factors for PE, who underwent successful arthroscopic meniscectomy. However, on the postoperative 9th day she developed dyspnea and tachycardia. Investigations carried out in the emergency department, including EKG, echocardiography, and CT angiography, supported the diagnosis of a PE. Heparin therapy was initiated, and the patient’s condition then improved sufficiently to allow follow-up at our outpatient department.

This article demonstrates that the degree of VEGF expression could be used as a clinically significant prognostic factor in osteosarcoma.

Satisfactory alignments of components in total knee arthroplasty have been reported since the introduction of navigation systems. And thus, such techniques have been introduced for minimally invasive unicondylar knee arthroplasty (UKA). Several intraoperative fractures of the tibial plateau have been reported in association with minimally invasive UKA and some stress fractures of tibial plateau associated with design of instrument have been reported. Here, we report on two cases of stress fracture of the tibial medial plateau after minimally invasive UKA was performed using a navigation system.

Although significant differences exist in the methods of treatment and prognoses of septic coxitis and transient synovitis in children complaining of acute hip pain, similar symptoms are present in these two diseases at the early stages, and differential diagnosis is difficult. To differentiate between these two diseases, the authors evaluated the clinical, serologic, and radiologic findings and tried to determine factors that could be used as diagnostic criteria. The authors performed a retrospective study by evaluating medical records, plain hip radiographs, and clinical findings in 97 patients with transient synovitis and 27 patients with septic arthritis. Univariate analysis showed significant differences in body temperature, serum WBC count, and ESR and CRP levels of the two patient groups. Plain radiographs showed a displacement or blurring of periarticular fat pads in all patients with acute septic arthritis, and multivariate regression analysis showed that body temperature >37 degrees C, ESR >20 mm/h, CRP >1 mg/dL, WBC >11,000/mL, and an increased hip joint space of >2 mm were independent multivariate predictors of acute septic arthritis. The authors conclude that the independent multivariate predictors are effective indices for the differential diagnosis of acute septic coxitis and transient synovitis.

Study design Retrospective study. Objectives To investigate the outcomes of fluoroscopically guided selective nerve root block as a nonsurgical treatment for cervical radiculopathy. Overview of literature Only a few studies have addressed the efficacy and persistence of cervical nerve root block. Methods This retrospective study was conducted on 28 consecutive patients with radicular pain due to cervical disc disease or cervical spondylosis. Myelopathy was excluded. Cervical nerve root blocks were administered every 2 weeks, up to 3 times. Outcomes were measured by comparing visual analogue scale (VAS) scores, patient satisfaction, and medication usage before the procedure and at 1 week and 3, 6, and 12 months after the procedure. In addition, complications associated with the procedure and need for other treatments were evaluated. Results The average preoperative VAS score was 7.8 (range, 5 to 10), and this changed to 2.9 (range, 1 to 7) at 3 months and 4.6 (range, 2 to 7) at 12 months. Patient satisfaction was 71% at 3 months and 50% at 12 months. Five patients used medication at 3 months, whereas 13 used medication at 12 months. Average symptom free duration after the procedure was 7.8 months (range, 1 to 12 months). Two patients were treated surgically. Only two minor complications were noted; transient ptosis with Horner's syndrome and transient causalgia. Conclusions Although selective nerve root block for cervical radiculopathy is limited as a definitive treatment, it appears to be useful in terms of providing relief from radicular pain in about 50% of patients at 12 months.

Study Design: This is a retrospective study. Objectives: To evaluated the clinical and radiological effectiveness of sacral alar screws for augmentation of S1 pedicle screws in longlevel fusion including L5-S1 segment. Summary of Literature Review: The fusion rates of lumbosacral junction in long-level fusion are various when S1 pedicle screws are used without augmentation. But, reports of sacral alar screw augmentation are rare. Material and Methods: From 1996 to 2005, 63 patients performed more than two-level fusion including lumbosacral junction were reviewed. 47 patients underwent lumbosacral fusion with S1 pedicle screws only (S1 group), and 16 patients with sacral alar screws augmentation in addition to S1 pedicle screws (S1-2 group). Radiologically, bony union, halo sign, and breakage of implants were evaluated. Clinically, complications associated with screw placement and general complications were evaluated. Results: Bony union was obtained in 56 cases(89%) at postoperative 4.3 months. Nonunion was observed in 7 cases(11%, S1 group:5, S1-2 group:2). Loosening of S1 pedicle screw was observed in 32 cases(89%) of S1 group and in 4 cases(25%) of S1-2 group. It showed statistical significance between two groups. Sacral alar screw loosening occurred in 8 cases(50%) of S1-2 group. Metal breakage was developed in 2 cases of S1 group without nonunion or loosening. Postoperative infection occurred in 7 cases(11%, S1 group:5, S1-2 group:2). Conclusions: Sacral alar screw augmentation was effective on protecting the loosening of S1 pedicle screw. Additional sacral alar screw can improve the rate of fusion for lumbosacral junction despite no statistical significance.

Study Design: This is a retrospective study. Objectives: We wanted to clarify the association between the position of the atlantoaxial fusion angle and the change of the subaxial cervical spine alignment (SCA) and the reduction loss after atlantoaxial fusion (AAF) using the posterior wiring technique (PWT), transarticular screw fixation (TAF) and posterior screw-rod fixation (PSR) for treating atlantoaxial instability (AAI). Summary of the Literature Review: There are not many studies on the change of the SCA and the reduction loss after AAF. Material and Methods: Thirty five patients underwent AAF for AAI from 1986 to 2008. The mean follow-up period was 59.5 months. The surgical techniques were divided into three groups, that is, PWT: 17 patients, TAS: 10 and PSR: 8. The causes of instability were transverse ligament rupture in 12 patients, rheumatoid arthritis in 11, Os odontoideum in 6 and nonunion of an odontoid fracture in 6. Plain radiographs were used to assess the atlanto-dental interval, the posterior arch-lamina angle, the change of the SCA and the time of fusion. Results: Fusion was achieved in all the patients within 3.5 months (range: 3-5 months). The radiologic findings in the 5 PWT patients showed a reduction loss and 3 patients showed subaxial cervical kyphosis (SCK). The TAS group had no reduction loss or SCK. The PSR group had no reduction loss and one patient showed SCK. A statistically significant reduction loss and SCK occurred in the group in which there was a posterior arch-laminar angle greater than 10 degrees before and after surgery. Conclusions: For the treatment of AAI, the position of the AAF is associated with the change of the postoperative SCA. The preoperative lodortic position of C1-2 should be maintained to prevent the change of the SCA.