Correlation between knee hyperextension gait and lower limb muscle activation in stroke patients with hemiplegia / 中国康复理论与实践

ObjectiveTo explore the correlation among knee hyperextension angle, lower limb joints kinematics parameters and the activation of main muscles of lower limb in stroke hemiplegic patients with knee hyperextension during walking. MethodsFrom August, 2020 to September, 2021, 24 stroke hemiplegic patients with knee hyperextension and 24 healthy subjects matched with sex, age, height and body mass with knee hyperextension were analyzed with three-dimensional gait analysis system and the wireless surface electromyography acquisition system, to record the range of motion of pelvis, hip, knee and ankle joints in sagittal plane, and the activation of bilateral gluteus maximus, biceps femoris, vastus medialis and gastrocnemius medialis. ResultsAs the maximum of knee hyperextension, range of motion of the joints in sagittal plane and the activation of the muscles were different between the patients and the healthy subjects during the single-support phase of walking (|t| > 3.080, P < 0.01), and the maximum of knee hyperextension correlated with the activation of gluteus maximus in the patients (r = -0.532, P < 0.01), and the range of motion of ankle plantar flexion in both the patients and the healthy subjects (r > 0.686, P < 0.001). ConclusionThe correction for knee hyperextension gait in stroke hemiplegic patients may not only need to pay attention to knee joint control, but also need further treatment of ankle control and hip muscle function.

Guidelines for management of pediatric acute hyperextension spinal cord injury / 中华创伤杂志(英文版)

Pediatric acute hyperextension spinal cord injury (SCI) named as PAHSCI by us, is a special type of thoracolumbar SCI without radiographic abnormality and highly related to back-bend in dance training, which has been increasingly reported. At present, it has become the leading cause of SCI in children, and brings a heavy social and economic burden. Both domestic and foreign academic institutions and dance education organizations lack a correct understanding of PAHSCI and relevant standards, specifications or guidelines. In order to provide standardized guidance, the expert team formulated this guideline based on the principles of science and practicability, starting from the diagnosis, differential diagnosis, etiology, admission evaluation, treatment, complications and prevention. This guideline puts forward 23 recommendations for 14 related issues.

Correlation between the characteristics of motor evoked potential and severity of spinal cord injury in patients with acute cervical hyperextension injury and central spinal cord syndrome / 中华创伤骨科杂志

Objective:To study the correlation between the acute-phase characteristics of motor evoked potential (MEP) and severities of spinal cord injury in patients with acute cervical hyperextension injury and central cord syndrome (CCS).Methods:Retrospectively analyzed were the data of 45 patients with acute cervical hyperextension injury and CCS (observation group) who had been admitted to Department of Orthopedics, Tongji Hospital Affiliated to Tongji University from December 2018 to July 2021 and 20 healthy controls. Examination of transcranial magnetic stimulation-induced MEP was performed in patients with CCS and healthy controls using a magpro x100 magnetic stimulator, and recording was conducted in bilateral abductor pollicis brevis (APB). The characteristics of MEP waveform latency, amplitude and motor threshold were described and compared between the healthy control and observation groups; the correlations were analyzed between the MEP latency and the severity of spinal cord injury [American Spinal Injury Association (ASIA) total score and motor function of Upper Extremity Motor Subscores (UEMS)] in the observation group. According to different MEP-induced states, the patients in the observation group were divided into a resting group ( n=19), a facilitation group ( n=18), and a no-waveform group ( n=8). The severity of spinal cord injury (ASIA total score) and the functional independence of the spinal cord (SCIM-Ⅲ score) were compared among the 3 groups to analyze the correlation between the MEP-induced state and the severity of spinal cord injury (ASIA total score). Results:The observation group had a significantly longer MEP latency [(30.16±6.32) ms], a significantly smaller amplitude [(0.54±0.30) mV] and a significantly higher motor threshold [(65%±11%)] than the healthy control group (all P<0.05). The MEP latency in the observation group was significantly correlated with ASIA total score ( r=-0.730, P<0.001) and UEMS ( r=-0.740, P<0.001). The ASIA total score and SCIM-Ⅲ score were significantly different among the 3 groups ( P<0.05), and the MEP-induced state was significantly correlated with the severity of spinal cord injury (ASIA total score) ( r=0.668, P<0.001). Conclusions:In patients with acute cervical hyperextension injury and CCS, the MEP latency is prolonged, the amplitude lowered, and the motor threshold enhanced. The MEP latency is strongly correlated with the severity of spinal cord injury and upper limb motor function. The MEP-induced state is also closely related to the severity of spinal cord injury.

Three-dimensional finite element analysis of traction under different lumbar physiological curvatures / 中国组织工程研究

BACKGROUND: In recent years, the finite element analysis of lumbar biomechanics has become a hot topic. Lumbar lordosis is considered to reduce the pressure load on the lumbar intervertebral disc and protect the lumbar spine. OBJECTIVE: To study the biomechanical effects of lumbar traction on L1-L5 lumbar segments in normal physiological curvature, flexion position and maximum overextension position, and to evaluate the optimal physiological curvature of lumbar traction. METHODS: A healthy male volunteer, aged 26 years, with a height of 174 cm and a weight of 60 kg, was selected, who had no history of lumbar spine diseases. With the L3 segment as the traction site, a finite element model of the whole lumbar spine was established based on lateral radiographs of the lumbar spine at the initiation site and during the maximal overextension as photographed by a DR machine. Based on the three-dimensional finite element model of the lumbar spine, the stress values and distributions of the lumbar vertebrae, the intervertebral joints, the intervertebral discs and the anterior longitudinal ligaments of the whole lumbar spine under different physiological curvatures were calculated. The patient was fully informed of the study protocol and signed an informed consent. The study protocol was approved by the Ethics Committee of Rehabilitation Hospital Affiliated to Fujian University of Traditional Chinese Medicine. RESULTS AND CONCLUSION: (1) Under six kinds of simulated working conditions, the range of motion of L1-L2 was 9.31° for flexion and extension, 9.84° for right and left bending, and 4.43° for right and left rotation; the range of motion of L2-L3 was 10.22° for flexion and extension, 12.35° for left and right bending, and 4.57° for left and right rotation; the range of motion of L3-L4 was 11.20° for flexion and extension, 11.63° for left and right bending, and 5.32° for left and right rotation; the range of motion of L4-L5 was 13.16° for flexion and extension, 11.58° for left and right bending, and 5.05° for left and right rotation. Under the normal physiological curvature of the lumbar vertebrae, the stress value of different lumbar spine structures was much greater than the stress value of hyperextension traction. The normal curvature of the anterior longitudinal ligament was 2.47 MPa, and the curvature of hyperextension traction value was 21.20 MPa. The stress value of L3 was the highest, which was four times that of the hyperextension traction. The stress value of the intervertebral joints at L2-L3 and intervertebral disc was highest than that of any other segment of the lumbar spine. These findings indicate that the pressure of lumbar vertebrae, intervertebral joints and intervertebral discs in hyperextension position is less than that in normal physiological curvature traction, and the pressure of anterior longitudinal ligament is always within the safe range. Lumbar traction may have better clinical efficacy and definite security in hyperextension position.

Open quadricepsplasty in hyperextension deformity of knee in children with arthrogryposis

Arthrogryposis includes heterogeneous disorders, characterized by congenital contractures of multiple joints. Knee involvement is very common (38–90 % of patients with amyoplasia) ranging from soft-tissue contractures (in flexion or hyperextension) to subluxation and dislocation. Children who present late will require surgery involving quadricepsplasty or lengthening of the contracted quadriceps muscle. Curtis and Fisher describe an open V-Y lengthening of the quadriceps femoris with post-operative immobilization in 30-45 ° of flexion. The main issue of this technique was limited degree of flexion that can be achieved, and the fibrous replacement of the quadriceps muscle. This is a neglected case of hyperextension deformity and congenital dislocation of knee in children with arthrogryposis resistant to conservative management and successfully treated by open quadricepsplasty.

Value of hyperextension MRI of cervical vertebra in determining decompression therapy after reduction of reducible atlantoaxial dislocation / 中华创伤杂志

Objective To determine the value of hyperextension MRI evaluation in determining whether to perform decompression therapy after reduction of reducible atlantoaxial dislocation as well as assess the decompression effect. Methods A retrospective case series study was conducted to analyze 24 patients with atlantoaxial dislocation admitted to Honghui Hospital affiliated to Xi'an Jiaotong University from May 2015 to May 2017. There were 10 males and 14 females, aged 40-74 years, with an average age of 52 years. There were 14 patients with os odontoideum, four patients with odontoid fracture, and six patients with transverse atlantal ligament rupture. Hyperextension MRI was performed to assess spinal cord compression for all patients. Eight patients with anterior spinal cord compression ( Group A ) underwent posterior atlantoaxial arch decompression plus atlantoaxial internal fixation reduction and bone graft fusion; 16 patients without anterior compression of the spinal cord ( Group B ) underwent only atlantoaxial internal fixation reduction and bone graft fusion. Intraoperative and postoperative complications were recorded. Spinal cord compression index and improvement rate of spinal cord decompression were evaluated by routine cervical spine MRI. Japanese Orthopedic Association ( JOA) score was used to evaluate the clinical effect. Results All patients were followed up for 3-24 months, with an average of 9. 3 months. There was no nerve or vertebral artery injury during the operation, and no screw loosening occurred after surgery. The spinal cord compression index (0. 37 ± 0. 18) in Group A at the last follow-up was significantly lower than that before operation (0. 73 ± 0. 22) (P<0. 05), while the index in Group B (0. 19 ± 0. 20) at the last follow-up was also lower than that before operation (0. 61 ± 0. 25) (P<0. 05). The improvement rate of spinal cord decompression was 67. 11％ in Group A and 70. 61％ in Group B. The final JOA score of Group A was ( 13. 29 ± 3. 68 ) points, which was significantlybetterthanthepreoperativeJOA[(5.61±2.74)points] (P <0.05). ThefinalJOA score in Group B [(14. 13 ± 3. 45) points] was also significantly better than the preoperative JOA [(7. 32 ± 2. 90)points] (P<0. 05). Improvement rate of JOA was 57. 31％ in Group A and 59. 91％in Group B. Conclusions Hyperextension MRI of cervical vertebra can effectively judge whether the anterior spinal cord is compressed after reduction of atlantoaxial dislocation. It has important clinical significance for decompression treatment during reduction and internal fixation of reducible atlantoaxial dislocation. At the same time, posterior atlantoaxial arch resection and decompression can effectively relieve the compression of the spinal cord after reduction of atlantoaxial dislocation.

Value of hyperextension MRI of cervical vertebra in determining decompression therapy after reduction of reducible atlantoaxial dislocation / 中华创伤杂志

Objective@#To determine the value of hyperextension MRI evaluation in determining whether to perform decompression therapy after reduction of reducible atlantoaxial dislocation as well as assess the decompression effect.@*Methods@#A retrospective case series study was conducted to analyze 24 patients with atlantoaxial dislocation admitted to Honghui Hospital affiliated to Xi'an Jiaotong University from May 2015 to May 2017. There were 10 males and 14 females, aged 40-74 years, with an average age of 52 years. There were 14 patients with os odontoideum, four patients with odontoid fracture, and six patients with transverse atlantal ligament rupture. Hyperextension MRI was performed to assess spinal cord compression for all patients. Eight patients with anterior spinal cord compression (Group A) underwent posterior atlantoaxial arch decompression plus atlantoaxial internal fixation reduction and bone graft fusion; 16 patients without anterior compression of the spinal cord (Group B) underwent only atlantoaxial internal fixation reduction and bone graft fusion. Intraoperative and postoperative complications were recorded. Spinal cord compression index and improvement rate of spinal cord decompression were evaluated by routine cervical spine MRI. Japanese Orthopedic Association (JOA) score was used to evaluate the clinical effect.@*Results@#All patients were followed up for 3-24 months, with an average of 9.3 months. There was no nerve or vertebral artery injury during the operation, and no screw loosening occurred after surgery. The spinal cord compression index (0.37±0.18) in Group A at the last follow-up was significantly lower than that before operation (0.73±0.22) (P<0.05), while the index in Group B (0.19±0.20) at the last follow-up was also lower than that before operation (0.61±0.25) (P<0.05). The improvement rate of spinal cord decompression was 67.11% in Group A and 70.61% in Group B. The final JOA score of Group A was (13.29±3.68)points, which was significantly better than the preoperative JOA [(5.61±2.74)points] (P<0.05). The final JOA score in Group B [(14.13±3.45)points] was also significantly better than the preoperative JOA [(7.32±2.90)points] (P<0.05). Improvement rate of JOA was 57.31% in Group A and 59.91% in Group B.@*Conclusions@#Hyperextension MRI of cervical vertebra can effectively judge whether the anterior spinal cord is compressed after reduction of atlantoaxial dislocation. It has important clinical significance for decompression treatment during reduction and internal fixation of reducible atlantoaxial dislocation. At the same time, posterior atlantoaxial arch resection and decompression can effectively relieve the compression of the spinal cord after reduction of atlantoaxial dislocation.

Research progress on hyperextension tibial plateau fractures / 中国修复重建外科杂志

Objective: To summarize the progress in the treatment of hyperextension tibial plateau fractures.

An accessory extensor pollicis longus tendon: a case report of rare anatomical variant / Tendón accesorio del músculo extensor largo del pulgar: reporte de caso de una rara variación anatómica

SUMMARY: Variation in the morphology of the extensor pollicis longus muscle is very rare. The muscle is considered as one of the deep group of dorsal forearm muscles. It passes through the dorsal radiocarpal ligament in a detached compartment. It inserts at the base of the distal phalanx of the thumb. The muscle might have double tendons where they run either in one, or in separate compartments. In this study, we report an extremely rare condition for a 38-year-old male where some of the tendon fibers split at the base of the proximal phalanx and the two tendons insert at the sides of the base of the distal phalanx. We also noticed a high range of hyperextension where the action was painless and showed no sign of discomfort. We believe that the way the tendons get inserted might have a role in this wide range of extension.

RESUMEN: La variación en la morfología del músculo extensor largo del pulgar es muy rara. Es considerado perteneciente al grupo profundo de los músculos del dorso del antebrazo. Su tendón pasa a través del ligamento radiocarpiano dorsal en un compartimiento separado. Se inserta en la base de la falange distal del pulgar. El músculo puede tener tendones dobles que pasan a través de un solo compartimiento, o en compartimentos separados, del ligamento radiocarpiano dorsal. En este estudio se reporta una variación extremadamente rara en un hombre de 38 años de edad, donde algunas de las fibras del tendón se dividen en la base de la falange proximal y los dos tendones se insertaban a los lados de la base de la falange distal del pulgar. También observamos un alto grado de hiperextensión siendo la acción indolora y no mostrando ningún signo de malestar. Creemos que la forma en que los tendones se insertan podrían tener un papel en este amplio rango de extensión.

Effects of 8-word bandage on walking ability in patients of stroke with knee hyperextension / 天津医药

Objective To observe the effect of the 8-word bandage on the walking ability of stroke patients with knee hyperextension. Methods Fifty patients with stroke combined with knee hyperextension were randomly divided into the observation group and the control group with 25 cases in each group. The control group was treated with conventional methods, including Bobath technology, Brunnstrom therapy and motor relearning primarily rehabilitation training. In addition to the conventional methods, patients in the observation group used 8-word bandage to fix knee joint in walking training. Before and after 8 weeks of treatment, Holden walking function classification, 10-meter maximum walking speed and improved Barthel index were adopted to evaluate the walking ability, maximum walking speed and the life ability of the patients. Results There were no significant differences in the scores before treatment between the two groups. The Holden walking function classification, the 10-meter maximum walking speed and the Barthel index scores were significantly improved after 8-week treatment in both two groups (P<0.05), and patient conditions were more significantly improved in the observation group than those of the control group (P<0.05). Conclusion Using 8-word bandage to fix knee joint can significantly improve knee hyperextension in patients with stroke, so as to improve the walking ability and activities of daily living.

Internal fixation for tibial plateau fractures involving anteromedial margin caused by hyperextension varus injury / 中华创伤骨科杂志

Objective To report the operative procedures and clinical outcomes of open reduction and internal fixation for the treatment of tibial plateau fractures involving anteromedial margin caused by hyperextension varus injury.Methods From December 2013 to December 2015,11 patients with tibial plateau fracture involving anteromedial margin caused by hyperextension varus injury were treated at our department.They were 6 males and 5 females with a mean age of 42.3 years (range,from 19 to 65 years).Simple medial column fracture happened in 2,fractures of medial and lateral columns in 4,fractures of medial and posterior columns in 3,and 3-column fractures in 2 cases.The cortical bone fractures of anteromedial margin were fixated by open reduction and internal fixation using self-clipped joint line plating.Bone grafting was conducted if necessary.Results The 9 patients were followed up for an average of 17.6 months (range,from 12 to 30 months).All the fractures healed.The average time for radiographic bony union and full weight bearing was 11.4 weeks (range,from 9 to 14 weeks) and 16.1 weeks (range,from 14 to 19 weeks),respectively.On average,the Rasmussen's radiological grading scored 16.9 (range,from 14 to 18)immediately after operation;the Hospital for Special Surgery scores of all the patients at 12 months postoperatively averaged 89.1 (range,from 75 to 94),yielding an excellent to good rate of 92.3％.The average range of motion of the affected knee was from 2.3° to 125.1°.There were significant differences in both tibial plateau angle and posterior slope angle on radiography between preoperation and postoperation (P ＜ 0.05).There were no significant differences in either tibial plateau angle or posterior slope angle on radiography between immediate postoperation and 12 months postoperation (P ＞ 0.05).Partial incision necrosis occurred postoperatively in one case which was uneventfully healed after wound management.One case complicated with preoperative common peroneal nerve injury reported dorsal sense of numbness which was healed after administration of neurotrophic drugs.No screw loosening,plate breakage or fixation failure was found during follow-ups.Conclusions It is difficult to treat the tibial plateau fractures involving anterumedial margin caused by hyperextension varus injury.Internal fixation with joint line plating is an appropriate treatment for this fracture pattern,leading to satisfactory clinical outcomes.

Application of DR in diagnosis of lumbar instability / 医疗卫生装备

Objective To apply DR to the diagnosis of lumbar instability.Methods Totally 198 patients suspected with lumbar instability underwent routine lateral side DR radiograph and examination of flexion-extension position to analyze the forward and backward displacements of the lumbar.Results Totally 35 patients with lumbar instability were determined based on the method proposed by White and Panjabi.Conclusion Film of flexion-extension position gains advantages over films of lateral position and oblique position in lumbar instability and malfunction, and thus helps for clinical diagnosis and efficacy observation.

Therapeutic effect of methylprednisolone combined with anterior decompression and internal fixation in treating cervical spine hyperextension injury / 中国生化药物杂志

Objective To analyse the therapeutic effect of methylprednisolone combined with anterior decompression and internal fixation in the treatment of cervical spine hyperextension injury. Methods 42 patients who were diagnosed with cervical hyperextension injury in orthopaedics department of the First Hospital of Jiaxing were collected.All patients were randomly divided into experimental group and control group, 21 cases in each group.Patients in control group received anterior cervical decompression and internal fixation only , patients in experimental group received methylprednisolone combined with anterior decompression and internal fixation, after treatment, the serum levels of TNF-α, SOD and American Spinal Injury Association (ASIA) score were detected in all patients.Results After treatment, compared with control group, the serum levels of TNF-αwas lower, SOD was higher and ASIA score was higher in experimental group, and the differences were statistically significant (P<0.05).Conclusion The methylprednisolone combined with anterior decompression and internal fixation could significantly reduce the serum level of TNF-α, and increase the serum level of SOD and ASIA score in patients with cervical spine hyperextension injury, could reduce the inflammatory damage, improve the antioxidant capacity, which has a good clinical effect.

Extension Type Locked Metacarpophalangeal Joint of the Little Finger due to Hyperextension Injury / 대한정형외과학회잡지

The extension type locked metacarpophalangeal joint of the little finger is an extremely rare condition characterized by loss of flexion with little or no loss of extension. The most common cause for locking is entrapment of a strap of the ruptured palmar plate. We treated a locked metacarpophalangeal joint of the little finger due to a hyperextension injury. The mechanism of locking was a torn part of the palmar ligament that forcefully rides across the prominence of the radial condyle of the metacarpal bone together with the accessory collateral ligament. These dislocated parts of the ligament formed a constricting bundle that prevented closed reduction. Locking was released successfully by an open reduction using the dorsal approach of the metacarpophalangeal joint without complication.

Application of hyperextension reduction with percutaneons kyphoplasty in treatment for osteoporotic vertebral compression fracture / 中国医师进修杂志

ObjectiveTo discuss the clinical efficacy of hyperextension reduction with percutaneous kyphoplasty in treatment for osteoporotic vertebral compression fracture.MethodsTwenty-three patients with 23 vertebral compression fractures underwent hyperextension reduction with percutaneous kyphoplasty from September 2010 to October 2011.The vasual analogue scale(VAS) score and complications were recorded during followed up.Results All cases were successfully experienced the procedure using unilateral or bilateral percutaneous pedicle underwent hyperextension reduction.The operation time was (75 ± 45) minutes,the mean volume of cement injected into each vertebral body was(4.9 ± 1.9) ml.All patients had successful intervention without spinal cord injury,pulmonary embolism.Followed up(7.5 ± 6.5 ) months,the symptoms of the patients were improved,preoperative VAS score was (7.5 ± 0.7 ) scores,reduced to (3.4 ±0.4) scores at day 1 postoperatively,(2.7 ±0.5) scores at day 7 postoperatively and (2.3 ±0.5) scores at month 1 postoperatively,there was significant difference between preoperative and postoperative (P＜ 0.05).ConclusionsApplication of hyperextension reduction with percutaneous kyphoplasty can relieve pain and restore the vertebral body height,it may be an effective treatment method for patients with osteoporotic vertebral compression fracture.

Proprioceptive Neuromuscular Facilitation Prevent Knee Hyperextension in Patients with Stroke / 中国康复理论与实践

@#Objective To study the effect of proprioceptive neuromuscular facilitation (PNF) on knee hyperextension in patients withstroke. Methods 60 patients with stroke were divided into treatment and control groups (30 cases each group). Both groups accepted medicineand routine rehabilitation, while the treatment group accepted PNF of knee additionally. Results The incidence of knee hyperextensionwas 7 (23.3%) in treatment group and 18 (60.0%) in control group (P<0.01) 3 months after treatment. The timed "up & go" improved morein the treatment group than in the control (P<0.01). Conclusion PNF of the knee at early stage of stroke can prevent knee hyperextensionand improve the walking.

Research on correlative factor of spinal segment distribution in cervical hyperextension injury / 中华急诊医学杂志

Objective To discuss the degenerative factors, the spinal segment distribution, and the mechanism in hyperextension injury of cervical spine. Method Eighty-nine patients with hyperextension injury of cervical spine were retrospectively analyzed by observing the degenerativelesion, the spinal cord segment with high signal in T2WI, and the location of facial trauma. Results Fifty-eight cases showed the disc hemiation which was the most common lesion, followed by 8 cases showing the calcification of the posterior longitudinal ligament. Besides, 7 cases presented the developmental stenosis of spinal canal, and also, 6 cases showed disc hemiation combined with the yellow ligament hypertrophy. The intervertebral level of the spinal cord with high signal in T2WI were distributed as follows:4 cases were at C2/3, of which onesuffered the forehead trauma; 12 cases were at C3/ 4, of which 10 had the forehead trauma, and one had the zygomatic trauma; 12 cases were at C4/5, of which 5 had the forehead trauma, one had both the zygomatic and the forehead trauma, and one had both the forehead and with the lower jaw trauma; 11 cases were at CS/6,of which 3 had the forehead trauma, 3 had the zygomatic trauma, and 2 had the lower jaw trauma. The location of the spinal cord with single high signal in T2WI did not correspond with the intervertebral disc level in 4 cases. For 10 cases the high signal in T2WI was found at two discontinuous segments. For 2 cases the 1 high signal in T2WI was found at over two segments. For 6 cases the high signal in T2WI was found at over three segments. Conclusions Disc hemiation is the most common underlyding factor in cervical hyperextension injury. The spinal level with high signal in T2WI was correlative to the impacted facial site. The shear force at the inflection point with or without the anterior-posterior compression force accounted for the cervical hyperextension injury.

Conservative Treatment of Genu Recurvatum: A Case Report

Genu recurvatum has commonly treated by Ilizarov devices, and treatment with an orthosis has rarely been reported. A 54 month old girl visited our hospital because of left knee hyperextension. The overall imbalance of the quadriceps with the hamstring muscles created 25 degrees of hyperextension. So we applied a knee-ankle-foot orthosis (KAFO) for treatment. After six months, the plain radiograph show 2 degrees hyperextension and stabilization of the knee. Genu recurvatum can be treated with an orthosis in a patient with imbalanced quadriceps and a hamstring muscle problem.

Influence of Posterior Tibial Slope on Stability after Total Knee Arthroplasty

PURPOSE: The purpose of this study was to compare the influence of posterior tibial slope on hyperextension deformities and anterior tibial translation between two types of total knee arthroplasty(TKA); posterior cruciate retaining(CR) and substituting(PS), which have different polyethylene conformity. MATERIALS AND METHODS: 109 consecutive primary TKAs using Nexgen(R)(Zimmer, Warsaw, IN) CR(n=60) and PS (n=49) type prostheses, performed from July 1995 to August 2005 were reviewed. Each group of CR and PS were divided into two categories according to the degree of posterior tibial slope; 0~5 degrees and more than 5 degrees. The amount of hyperextension deformities and anterior tibial translation measured at the immediate and postoperative 2 years radiographs were analyzed in each subdivided groups. RESULTS: The significant amount of hyperextension deformities(p<0.05) and anterior tibial translation(p<0.05) were noted in the CR group. The CR group with more than 5 degrees of posterior tibial slope was more prone to develop the hype- rextension deformities(p=0.003) and anterior tibial translation(p=0.007) compared with the group that has posterior tibial slope less than 5 degrees. But in the PS group, there was no significant difference related with hyperextension deformities (p =0.240) and anterior tibial translation(p=0.204) between the two groups. CONCLUSION: The posterior tibial slope more than 5 degrees resulted in increments of the hyperextension and anterior tibial translation in the CR TKA group than in the PS TKA group.

Imaging appearance and clinical significance of the hyperextension injury at cervical spine / 中国矫形外科杂志

[Objective]To investigate imaginological evidences of hyperxtensive injury of cervical spine and to evaluate its use in clinics.[Method]Seventy-eight patients with hyperextension injury at cervical spine by different cause were estimated by radiograph、CT and MRI.Fifty-seven cases(73.1%) appeared with widen of soft tissue of anteriorspine,including focal type(17.5%) and diffused type(82.5%). Thirty-six cases showed avulsion fracture of anterior edge in the cervical spine. Sixty-three cases showed degeneration and developmental spinal stenosis,twenty-one cases appeared integral vertebral canal. No contrast CT scan showed osteophyte of thirty-seven cases and intervertebral discs degeneration and protrusion of twenty-one cases.Sixty-one cases(78.2%) with both disc and anterior-longitudinal-ligament injury showed by MRI,fifty-seven cases showed haematoma and oedema at the anterior of the vertebral body. Sixty-four cases accompanied with different spinal cord injury.[Result]Obvious imaging feature for hyperextension injury of cervical spine,including anterior longitudinal ligament,intervertebral disc and spinal cord were found.There exists good relationship between spinal cord injury and imaging appearance. Clinically it showed typical central syndrome,but mostly showed us neuron-functional disturbance of different degree.[Conclusion]Combining of imaginological apperarance including radiograph,CT,MRI can provide evidences for diagnosis of hyperextension and help to treat acute hyperextension cervical injury.