Tehran University Medical Journal

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This was a retrospective review of a consecutive series of patients with spinal disease in year 2000, who underwent posterior fusion and instrumentation with Harrington distraction and Cotrel-Dobousset system to evaluate causes of hardware failure. Many cases of clinical failure has been observed in spinal instrumentation used in spinal disorder like spondylolisthesis, fractures, deformities, … . Thirty six cases that were operated because of spinal disorders like spondylolisthesis, fractures, deformities, …, were included in this study. Seventeen of this cases had breakage of device. Factors like age at surgery, type of instrumentation, angles before and after surgery and …, were compared in two groups of patients. The most common instrument breakage was pedicle screw breakage. Pseudoarthrosis was the main factor that was presented in failure group (P value<0.001). Other important causes were, age of patient at surgery (P value=0.04), pedicle screw placement off center in the sagittal or coronal plane of the pedicle (P value=0.04). Instrumentation loads increased significantly as a direct result of variations in surgical technique that produce pseudoarthrosis, pedicle screw placement off center in the sagittal plane of the pedicle, or using less than 6 mm diameter screw. This factor can be prevented with meticulous surgical technique and using proper devices.

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Background: The goal of this study was to evaluate, functional capacity of the knee in flexion and internal rotation after hamstring ligament harvest for Anterior Cruciate Ligament (ACL) reconstruction.
Methods: Fifty patients (male and 18-45 years old) with isolated ACL injury, randomly allocated in two equal groups (in one group, ACL reconstruction was performed with Tibialis Posterior allograft and in another group with quadruple hamstring ligament auto graft) and before and 6 months after surgery in both groups isokinetic flexion strength and isometric internal rotation strength of knee evaluated with Biodex System 4 dynamometer and rotational torque recorder, in order. Isokinetic flexion strength evaluated in sitting and prone position the later position was performed for deep flexion strength evaluation. Also subjective and objective assessment of all patients pre operatively and 6 months post operatively was documented with International Knee Documentation Committee (IKDC) questionnaire. In this study for first time, rotational torque strength of knee was recorded with new design measure, from isometric aspect and not isokinetic.
Results: Although significant improvements in IKDC scores, flexion and internal rotation capacity of the knee were observed in both groups, post operatively in respect to pre operatively there was no significant difference between 2 groups. (P<0.05 or more than 95% confidence Interval of the difference)
Conclusion: This study demonstrates that ACL reconstruction surgery, improves knee performance in flexion and internal rotation, regardless of hamstring tendon harvesting. Considering potential complications of allograft (for example: transfer of harmful diseases from donor to recipient), it is logical to use hamstring auto graft ligament for ACL reconstruction surgery. Because result of this study is not longstanding follow up and limited to male sex, for more worthfull conclusion, we suggest future study in both sex and with long duration of follow up.