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Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_3 | Pages 71 - 71
1 Jan 2016
Nabavi A Olwill C
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Aim

To asses the accuracy of total knee replacements performed using CT based patient specific instrumentation by postoperative CT scan.

Method

Approval from the Ethics Committee at The University of New South Wales Sydney Australia was granted prior to commencement of this study. 50 patients who had undergone total knee replacement (Evolis, Medacta International) using CT-based patient specific instrumentation (MY KNEE Medacta International) were assessed postoperatively using a CT scan and a validated measurement technique. The mechanical axis of the limb in the coronal plane, the varus/valgus positioning of the femoral component, the varus/valgus positioning of the tibial component, the flexion/extension of the posterior flange of the femoral component and the posterior slope of the tibial base plate were recorded. These results were then compared to each patient's preoperative planning. The percentage of patients found to be within 3 degrees of planned alignment were calculated. This represents the most comprehensive prospective study to utilize CT assessment of postoperative alignment in patient specific instrumentation. All other studies, to our knowledge have utilized scanograms or scout images and not full CT protocol as performed in this study.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIII | Pages 77 - 77
1 May 2012
Nabavi A
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This study describes a safe endoscopic technique for decompression of trochanteric bursa and presents the results of this procedure.

Fifteen patients who had failed non-operative treatment for trochanteric bursitis were treated by endoscopic lengthening of fascia lata (FL) and trochanteric bursectomy. Two patients had also failed open decompressions performed at another institution prior to their endoscopic surgery. All patients took part in questionnaires pre-operatively and at three months and twelve months. A two-portal endoscopic procedure was performed in all subjects. A Cruciate incision was made in the FL hence lengthening it in three dimensions. A trochanteric bursectomy was then performed using a mechanical shaver.

No patients were lost to follow up. At last review 14 patients rated their result as excellent and one patient had a fair result. There were no complications. The modified Harris hip score improved from 45 to 60, Non-arthritic hip score improved from 45 to 64 and SF12 score improved from 31 to 34.

Endoscopic lengthening of FL and trochanteric bursectomy is a safe and effective procedure in relieving the symptoms of persistent trochanteric bursitis.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIII | Pages 73 - 73
1 May 2012
Nabavi A
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This study presents the results of 60 consecutive hip arthroscopic procedures for the treatment of Acetabulo-Femoral Impingement. The procedures were performed by a single surgeon over a period of 36 months. The learning curve and the evolution of the current technique along with the clinical outcomes are discussed Additionally two new clinical signs of AFI are described, along with the correlation of radiological and arthroscopic findings.

Sixty patients underwent hip arthroscopies. The procedures included labral debridement, labral repair, femoral and/or acetabular osteectomies. All patients underwent MRI examination and three-dimensional CT imaging to identify the impingement lesion. Follow up CT scanning was performed to assess the accuracy of the bony resection. Patients were reviewed at three months and subsequently at twelve monthly intervals. All patients participated in completing questionnaires.

Post-operatively Modified Harris Hip score improved from 54 to 70, Non-Arthritic hip score improved from 58 to 75, SF12 score improved from 35 to 40. Three patients required a second procedure for further bony resection. One patient underwent a THR within 12 months. Two female patients suffered minor vaginal abrasions.

Hip arthroscopy is a demanding procedure. Good clinical results are achieved only when the cause of impingement has been identified and treated.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_IV | Pages 494 - 494
1 Apr 2004
Nabavi-Tabrizi A Stubbs G McKewin S
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Introduction The AO/ASIF 3.5 mm STS is increasingly used for internal fixation of large bones with the recent introduction of the 3.5 mm periarticular plating system. Our study aims to compare the insertion torque and mechanical properties of the screw after insertion into bovine femora using non tapped and pretapped methods.

Methods Three groups of ten 3.5 mm AO/ASIF STSs of variable lengths were used. One group was put aside as the control. One group was inserted into fresh bovine femora using pre-tapped drill holes and the final group using non-tapped drill holes. The insetion torques were measured and compared using an analogue torque screw driver. All screws were removed. The three groups were then tested for mechanical strength. The results of the groups were compared we found the insertion torque to be six times greater in the non tapped group compared to the pre tapped group. We noted the non tapped group failed later than the pre-tapped group, this was statistically not significant however. The mechanical strength of the screw was not statistically altered.

Conclusions We conclude that the 3.5 mm STS is easier to insert when pre tapped. However pre tapping is not necessary to preserve the mechanical strength of the screw.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 238 - 238
1 Nov 2002
Nabavi-Tabrizi A Turnbull A Dao Q Appleyard R
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Introduction: Osteochondral mosaic plasty is gaining popularity as a treatment for isolated chondral defects in femoral condyles. Most systems use a metal punch to impact the osteochondral grafts in pre-drilled defects. Damage to the chondrocytes during impaction grafting is of concern and new methods are being sort to minimise this deleterious effect.

This study was designed to see if using a plastic punch instead of a metal punch reduces the extent of chondrocyte damage in osteochondral mosaic plasty.

Method: Ten fresh sheep knees were used to harvest thirty osteochondral plugs using the COR system. The opposite condyles were then prepared to receive the osteochondral grafts. Ten plugs were impacted using a metal punch and ten using a plastic punch. The ten remaining plugs were used as controls. The plugs were then recovered and incubated for 24 hours prior to being stained with MTT. The stained cartilage was then photographed using a digital macroscope.

Images were interpreted using a graphics analysis programme.

Results: There was no significant difference in the extent of chondrocyte damage between the two groups. However, the extent of chondrocyte damage in the impacted groups was significantly greater than the control group.

Conclusion: Impaction grafting clearly damages chondrocytes of the osteochondral plug. In our study using a plastic punch did not reduce the extent of chondrocyte damage during mosaic plasty.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 286 - 286
1 Nov 2002
Nabavi-Tabrizi A Turnbull A Dao Q Appleyard R
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Introduction: Osteochondral mosaicplasty is gaining popularity as a treatment for isolated chondral defects in femoral condyles. Most systems use a metal punch to impact the osteochondral grafts in pre-drilled defects. Damage to the chondrocytes during impaction grafting is of concern and new methods are being sort to minimise this deleterious effect. This study was designed to see if using a plastic punch instead of a metal punch reduces the extent of chondrocyte damage in osteochondral mosaic plasty.

Method: Ten fresh sheep knees were used to harvest 30 osteochondral plugs using the COR system. The opposite condyles were then prepared to receive the osteochondral grafts. Ten plugs were impacted using a metal punch and ten using a plastic punch. The ten remaining plugs were used as controls. The plugs were then recovered and incubated for 24 hours before being stained with MTT. The stained cartilage was then photographed using a digital macroscope. The images were interpreted using a graphics analysis programme.

Results: There was no significant difference in the extent of chondrocyte damage between the two groups. However the extent of chondrocyte damage in the impacted groups was significantly greater than the control group.

Conclusions: Impaction grafting clearly damaged the chondrocytes of the osteochondral plug. In our study using a plastic punch did not reduce the extent of chondrocyte damage during mosaicplasty.