Surgical Biomechanics of the Patellofemoral Joint

This review presents objective data, as far as possible, about the current understanding of the biomechanics of the patellofemoral joint as it pertains to the management of patellofemoral problems. When faced with a patellofemoral malfunction, it is important to check all the soft-tissue and articular geometry factors relating to the patella locally and not to neglect the overall lower limb alignment and function. It is important to remember that small alterations in alignment can result in significant alterations in patellofemoral joint stresses and that changes in the mechanics of the patellofemoral joint can also result in changes in the tibiofemoral compartments. Surgical intervention for patellofemoral problems needs to be planned carefully and take into account an individual’s anatomy.     

Combined Bankart and HAGL lesion associated with anterior shoulder instability

Traumatic anterior shoulder instability has been shown to be associated with a spectrum of capsulolabral pathology, including separation of the labrum (Bankart lesion), capsular rupture, and humeral avulsion of the glenohumeral ligaments (HAGL lesion). We describe a case of combined Bankart and HAGL lesions, a condition that has not been described before. Careful anatomic repair of both components of this bipolar capsular injury resulted in an excellent outcome.     

胫骨高位截骨术治疗膝内翻伴膝外摆步态的疗效与不足

[目的]探讨外侧闭合胫骨高位截骨术治疗膝内翻伴膝外摆步态患者的临床效果及相关的影响因素。[方法]随访2000~2004年因膝内翻伴膝外摆步态于本院行胫骨高位截骨手术的患者19例,年龄47~54岁,随访时间6个月~4 a。术前及术后X线片测量股骨-胫骨角、胫骨平台后倾角和腓骨小头高度,HSS膝关节功能评分,关节后外侧稳定性测试,术后患者以五点问卷法评价术后关节稳定性的改善情况。[结果]股骨-胫骨角术前184.5°~197°,术后167°~176°;腓骨小头高度术前7.73~18.5 mm,术后-3.5~10.7 mm;胫骨后倾角术前2°~17°,术后-4°~13°;HSS评分术前48~68分,术后60~91分(P=0.00)。后外侧的稳定性测量术前Ⅰ度损伤16例,Ⅱ度损伤3例。术后Ⅰ度损伤9例,Ⅱ度损伤10例(P<0.05)。术后患者关节稳定性的问卷4例明显提高,9例有提高,6例与术前相同。[结论]外侧闭合胫骨高位截骨治疗膝内翻合并膝外摆的近期效果良好,远期效果可能受到膝外摆步态、胫骨后倾角和腓骨小头高度改变的影响。     

Three-dimensional bone kinematics in an anterior laxity test of the ankle joint

Questions addressed in this in-vitro study are (1) what are the actual three-dimensional kinematics of talus and calcaneus during an anterior drawer test as performed with the quasi-static anterior ankle tester (QAAT) (2) does laxity measurement with the QAAT represent the true anterior translation of talus relative to the tibia?. Simultaneous measurements were made with the QAAT and a three-dimensional kinematics analysis system in five specimens. The three-dimensional translations and rotations on three axes were analysed at 25, 50 and 100 N of applied anterior load, with increased ligament damage. For four out of five remaining specimens, anterior translation values of talus and calcaneus and values as measured with the QAAT show a significant increase with growing ligament damage and with higher loads. Skeletal motions of talus and calcaneus show great similarity in three different motion axes, with increased ligament damage and at any given load. Skeletal translations and rotations of talus and calcaneus show great similarity during an anterior drawer movement of the ankle joint. Anterior skeletal translation of the talus and calcaneus show fair correlation with the anterior displacements measurements of the QAAT. These QAAT measurements show an overestimation of the laxity value by more than 200% irrespective of the load applied.     

Assessment of instability in type B pelvic ring fractures

Pelvic ring fractures have increased in incidence and operative fixation over the past several decades. These are dynamic injuries but decisions on operative management are still often made on the basis of static imaging. Expert opinion varies greatly on which injuries require fixation and how much fixation. Examination under anaesthesia has been shown to guide management of pelvic injuries by more accurately assessing levels of instability.     

Transpedicular reduction and stabilization for postlaminectomy lumbar instability

Summary This study retrospectively reviewed the outcomes of 17 patients with postlaminectomy lumbar instability treated by transpedicular reduction and stabilization. The criteria of instability were defined strictly by both the clinical symptom of instability catch and the radiological findings that fulfilled Nachemson's criteria. Low back pain and/or sciatica that interfered largely with the patients' work or quality of life were the indications for this treatrment. All the operations were performed by one surgeon with the same spinal instrumentation system — AO internal fixator. The follow-up period was between 16 and 36 months (mean 24 months).Face to face questionnaire revealed that this treatment modality is encouraging. Fourteen patients (82%) had complete or nearly complete relief from all the pre-operative symptoms. Two (12%) had partial relief of the symptoms that required a subsequent discectomy or wider laminectomy. Only one case (6%) with osteoporosis remained unchanged after the operation. On the follow-up radiographs, sixteen patients (94%) showed good alignment and solid arthrodesis of the treated motion segment. These radiological findings correlated quite well with the absence of the clinical symptom of instability catch.A common, but acceptable, complication found in this series was a variable degree of low back stiffness secondary to the instrumentation. Fracture of the screw was found in one patient and pull out of the screw was found in another patient. However, they did not elicit detectable symptoms.Osteoporosis, concomitant disc herniation and persistent spinal stenosis at/or adjacent to the operated level were the three main factors that may contribute to unsatisfactory results secondary to this treatment. These problems remain to be resolved in thp future.     

蛋白质不稳定性及其分析技术

蛋白质不稳定性包括两种形式：化学不稳定性和物理不稳定性，这两种不稳定性可采取不同的分析技术。了解蛋白质不稳定性及其分析技术在生物工程药物的质量控制中有十分重要的作用。