fa جراحی زانو Knee surgery <div style="text-align: justify;"><strong>Background</strong>: As a minimally invasive operation, kyphoplasty has become popular in the treatment of osteoporotic vertebral compression fracture (OVCF).<br> <strong>Objectives</strong>: This study aimed to evaluate how the timing of kyphoplasty affects the parameters of sagittal alignment in OVCF.<br> <strong>Methods</strong>: In this prospective study, the patients with OVCF, who underwent kyphoplasty at our center, were recruited. Pre- and post-operative vertebral height, local and total kyphosis, coronal axis, sagittal vertebral axis, pelvic tilt, lumbar lordosis, sacral slope, and spino-cranial angle were evaluated and compared between acute OVCF (kyphoplasty performed within 1 month after injury) and chronic OVCF (kyphoplasty performed after 1 month from injury) patients.&lrm;<br> <strong>Results</strong>: Kyphoplasty was done for 18 acute and 28 chronic OVCF patients. All of the evaluated parameters, except spino-cranial angle, were significantly improved after the kyphoplasty. A significant difference was observed between the mean lumbar lordosis improvement of the two groups (P=0.026). In particular, the Mean&plusmn;SD lumbar lordosis improved 6.1&plusmn;6.6&ordm; in the acute patients and 0.92&plusmn;7.86&ordm; in the chronic group. No other significant difference was observed between the improvement of the spinopelvic parameters in the two groups.<br> <strong>Conclusion</strong>: The timing of kyphoplasty impacts the improvement of spinopelvic parameters, &lrm;as well as the reduction of pain and restoration of vertebral height.&nbsp;</div> Kyphoplasty, Osteoporosis, Vertebral compression fracture, Sagittal alignment 1 6 http://jros.iums.ac.ir/browse.php?a_code=A-10-41-67&slc_lang=fa&sid=1 Farshad Nikouei 10031947532846003818 10031947532846003818 No Bone and Joint Reconstruction Research Center, Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran. Hasan Ghandhari 10031947532846003819 10031947532846003819 No Bone and Joint Reconstruction Research Center, Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran. Mohammadamin Haghbin 10031947532846003820 10031947532846003820 No Bone and Joint Reconstruction Research Center, Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran. Omid Momen 10031947532846003821 10031947532846003821 Yes Bone and Joint Reconstruction Research Center, Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran. Amir Aghaie Aghdam 10031947532846003822 10031947532846003822 No Bone and Joint Reconstruction Research Center, Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran.