Intermittent Hypoxic Therapy Inhibits Allogenic Bone-Graft Resorption by Inhibition of Osteoclastogenesis in a Mouse Model

Systemic Intermittent Hypoxic Therapy (IHT) relies on the adaptive response to hypoxic stress. We investigated allogenic bone-graft resorption in the lumbar spine in 48 mice. The mice were exposed to IHT for 1 week before surgery or 1 week after surgery and compared with controls after 1 and 4 weeks. Complete graft resorption was observed in 33–36% of the animals in the control group, but none in the preoperative IHT group. Increased bone-graft volume was demonstrated by micro-computed tomography in the preoperative IHT group after 1 week (p = 0.03) while a non-significant difference was observed after 4 weeks (p = 0.12). There were no significant differences in the postoperative IHT group. Increased concentration of immune cells was localized in the graft area, and more positive tartrate-resistant acid phosphatase (TRAP) staining was found in controls compared with IHT allogenic bone grafts. Systemic IHT resulted in a significant increase of the major osteoclast inhibitor osteoprotegerin as well as osteogenic and angiogenic regulators Tgfbr3, Fst3l, Wisp1, and Vegfd. Inflammatory cytokines and receptor activator of nuclear factor kappa-B ligand (RANKL) stimulators IL-6, IL-17a, IL-17f, and IL-23r increased after 1 and 4 weeks, and serum RANKL expression remained constant while Ccl3 and Ccl5 decreased. We conclude that the adaptive response to IHT activates numerous pathways leading to inhibition of osteoclastic activity and inhibition of allogenic bone-graft resorption.

How to prevent graft resorption or breakage in shelf acetabuloplasty for Perthes disease with hinge abduction – A modified Staheli technique successful in 31 hips in midterm results

BACKGROUND: Shelf acetabuloplasty covers the hip and allows remodeling in hips with Legg-Calv-Perthes disease and hinge abduction. Graft resorption or breakage is a bad complication that necessitate another surgical procedure. AIM: Our report evaluates a modified Staheli technique for graft resorption or breakage. MATERIALS AND METHODS: Case series study of 31 hips (29 patients) with mean age at operation was 8.1 (range 6-14 years). Duration of complaint ranged between one year and up to three years with the mean duration 1.52 0.76 years. The different parameters evaluating the hip as: Tnnis angle, Sharp angle, center-edge angle, and acetabular coverage percentage were measured. For unilateral cases only, medial joint space ratio and epiphyseal height ratio were evaluated. RESULTS: The mean postoperative follow-up was 47.8 9.8 months. All studied joints had Catterall type IV, Salter-Thompson classification type B. Seven joints were in Fragmentation stage whereas 24 joints were in re-ossification stage. Based on Lateral Pillar classification; only two joints were classified as B/C and 29 joints were classified as C. Final follow up internal rotation, abduction, center-edge angle, and acetabular coverage percentage were found to be significantly higher. In contrast, Tnnis angle and Sharps angle were significantly decreased. For unilateral cases, it was found that medial joint space ratio and epiphyseal height ratio were significantly decreased. None of the hips had resorbed or broken graft till final follow up. CONCLUSIONS: This modified Staheli technique prevent graft resorption or breakage. Shelf provides a good acetabular coverage for the deformed aspherical head with Legg-Calv-Perthes disease and hinge abduction to improve hip clinical and radiological outcome.

Salvage Iliac Crest Bone Grafting for a Failed Latarjet Procedure: Analysis of Failed and Successful Procedures

Background: The Latarjet is a successful procedure but can be associated with significant complications, including failure. Iliac crest bone grafting (ICBG) is one of the salvage options for such failure. Purpose: To analyze factors associated with failure or success to restore shoulder stability with ICBG after Latarjet failure. Study Design: Case series; Level of evidence, 4. Methods: Twenty consecutive patients with recurrence of instability after a Latarjet procedure underwent revision using ICBG. Sixteen patients (80%) with a mean age of 35.0 years (range, 25-55) could be personally reexamined clinically and radiographically (including computed tomography scan) after a mean follow-up of 4.5 years (range, 2-8). Twelve patients had redislocation and 4 had recurrent subluxation after the Latarjet. Results: Salvage ICBG failed in 7 patients because of recurrent dislocations, with 5 necessitating reoperations: 2 arthrodeses, 1 reverse total shoulder arthroplasty, 1 repeat ICBG, and 1 Hill-Sachs allograft reconstruction and Bankart repair. Factors associated with ICBG failure were multidirectional instability (n = 2), subscapularis insufficiency (n = 1), uncontrolled seizures (n = 1), static inferior glenohumeral subluxation (n = 1), total graft resorption (n = 1), and voluntary dislocation attributed to schizoaffective disorder (n = 1). The initial Latarjet graft was malpositioned (too medial) in 3 of these patients. In patients without recurrent instability (n = 9), reasons for Latarjet failure were graft related: 6 graft avulsions, 2 graft resorptions, and 1 medial graft malpositioning. The mean absolute Constant score (62 to 87 points, P = .012) and relative Constant score (66% to 91%, P = .012), pain (10 to 15 points, P < .001), and Subjective Shoulder Value (31% to 85%, P = .011) in the group with a successful procedure were significantly improved over the preoperative state, and the total Western Ontario Shoulder Instability Index averaged 64% at final follow-up. Except in 1 case of major resorption, mild graft resorption or none was observed in successful procedures. Axial and sagittal graft positioning was good in all 9 patients. Conclusions: Salvage ICBG for failed Latarjet procedures failed in 7 of 16 patients. It was successful in patients with clearly graft-related factors of the initial Latarjet procedure. However, patients with unclear instability symptoms, subscapularis insufficiency, inferior subluxation, uncontrolled seizures, or psychological disorders were poor candidates for salvage ICBG, underlining the importance of careful patient selection for the initial Latarjet procedure and for salvage ICBG.

Resorption of retromolar bone grafts after alveolar ridge augmentation—volumetric changes after 12 months assessed by CBCT analysis

In this pilot study, a volumetric analysis of retromolar onlay bone grafts over a period of 12 months was conducted, using repeated CBCT imaging combined with automated image registration.Eleven patients being treated with 16 bone grafts taken from the retromolar area were examined by CBCT scanning prior to bone augmentation (T0), immediately after bone augmentation (T1) and after a healing time of 12 months after augmentation (T2). Graft volumes were measured at each time point after automated image registration of consecutive CBCT scans.The mean volume of the augmented site was 372.2 ± 179.4 mm3. Resorption relative to the original augmented volume was 43.7% ± 19.0% after 12 months.Three-dimensional graft resorption could be precisely depicted by the use of automated image registration for CBCT data over a period of 12 months and demonstrated extensive volumetric changes of bone grafts taken from the ascending ramus of the mandible.Graft resorption and continuous bony remodeling of the grafted site before and after implant insertion have to be carefully considered by the clinician.