Use of freeze-dried bone allograft with platelet-derived growth factor for revision of a glenoid component

The Use of Glenoid Structural Allografts for Glenoid Bone Defects in Reverse Shoulder Arthroplasty

Background: The use of reverse shoulder arthroplasty as a primary and revision implant is increasing. Advances in implant design and preoperative surgical planning allow the management of complex glenoid defects. As the demand for treating severe bone loss increases, custom allograft composites are needed to match the premorbid anatomy. Baseplate composite structural allografts are used in patients with eccentric and centric defects to restore the glenoid joint line. Preserving bone stock is important in younger patients where a revision surgery is expected. The aim of this article is to present the assessment, planning, and indications of femoral head allografting for bony defects of the glenoid. Methods: The preoperative surgical planning and the surgical technique to execute the plan with a baseplate composite graft are detailed. The preliminary clinical and radiological results of 29 shoulders which have undergone this graft planning and surgical technique are discussed. Clinical outcomes included visual analogue score of pain (VAS), American Shoulder and Elbow Surgeons score (ASES), Constant-Murley score (CS), satisfaction before and after operation, and active range of motion. Radiological outcomes included graft healing and presence of osteolysis or loosening. Results: The use of composite grafts in this series has shown excellent clinical outcomes, with an overall graft complication rate in complex bone loss cases of 8%. Conclusion: Femoral head structural allografting is a valid and viable surgical option for glenoid bone defects in reverse shoulder arthroplasty.

Effects of pulsed electromagnetic stimulation on patients undergoing hip revision prostheses: a randomized prospective double-blind study

In this prospective, randomized, double-blind study, the effect of Pulsed Electromagnetic Fields (PEMFs) was investigated in 30 subjects undergoing hip revision using the Wagner SL stem. The subjects were treated for 6 h/day up to 90 days after revision. Study end points were assessed clinically by the functional scale of Merle D'Aubigné and instrumentally by Dual-Energy X-ray Absorptiometry (DXA) at the Gruen zones. Subject improvement according to Merle D'Aubigné scale was higher (P < 0.05) in subjects undergoing active stimulation compared to placebo. In analyzing the DXA findings, we subtracted for each area the postoperative bone mineral density (BMD) values from those measured at 90 days and we considered all results above 3.5% as responders. There were no significant differences in the average BMD values at each Gruen zone between the two groups both postoperatively and at 90 days investigation. In Gruen zones 5 and 6, corresponding to the medial cortex, we observed six responders (40%) in both areas in the control group, while in the stimulated group we observed 14 (93%) and 10 (66%) responders, respectively (both P < 0.05). This study showed that PEMF treatment aids clinical recovery and bone stock restoration.

In vitro evaluation of freeze-dried bone allografts combined with platelet rich plasma and human bone marrow stromal cells for tissue engineering

Freeze-dried bone allograft (FDBA) might be more effective in combination with platelet rich plasma (PRP) and bone marrow stromal cells (BMSC) in accelerating bone healing. The isolation of BMSC through density gradient (pBMSC) is not extensively applicable in clinical practice, because it increases the risk of infection. Alternatively, BMSC can be concentrated by simple centrifugation (wBMSC) directly in the operating room. However, we do not know if wBMSC act in the same way as pBMSC. BMSC from 10 donors were tested whether, in the presence of a combination of FDBA and autologous PRP, the osteogenic differentiation of the cells concentrated by simple centrifugation (wBMSC + FDBA + PRP) was similar to that of pBMSC. Cell-associated alkaline phosphatase, osterix and fibroblast growth factor-2 were higher in wBMSC + FDBA + PRP. In conclusion, the combination of FDBA and PRP had a favouring effect on the differentiation towards osteoblasts and allowed BMSC concentrated by simple centrifugation to differentiate as fast as BMSC purified by density gradient.

The effect of screw position on the initial fixation of a reverse total shoulder prosthesis in a glenoid with a cavitary bone defect

Patients with rotator cuff tear arthropathy can be treated successfully with a reverse total shoulder prosthesis. In patients with significant glenoid bone loss, achieving stable bone fixation can be challenging, as the surgeon must know when bone grafting is necessary and when the plan to implant the reverse total shoulder prosthesis should be abandoned because of the likelihood of early implant loosening. The purposes of this study were (1) to determine the initial stability of a metal glenoid implant fixed in a glenoid with a central cavitary defect and (2) to determine whether an altered screw configuration would sufficiently resist implant micromotion and, thereby, allow bone ingrowth to occur. The Delta III reverse total shoulder glenoid implant was fixed into foam scapulae with a uniform density similar to normal glenoid bone density. The control group implants were fixed into foam scapulae without a glenoid defect, by use of the standard surgical technique for screw placement. The second group was fixed into foam scapulae containing a central cavitary glenoid defect, by use of the standard surgical technique for screw placement. The central cavitary defect was meant to simulate the bone loss typically found after the removal of a loose pegged glenoid implant, and it was created with a 4-pegged glenoid drill guide. A third group was fixed into foam scapula with a central cavitary glenoid defect, with an experimental screw configuration by use of a posterior screw directed toward the spine of the scapula and an anterior screw directed inferior to the central peg. All specimens were loaded with 500 cycles of 1 body weight (70 kg) to simulate the forces generated during arm elevation that occur during the first 3 months after surgery. Micromotion between the implant and the foam bone was measured with a digital video motion analysis system (accuracy, +/- 2.6 microm). After loading of the implant with 70 kg for 500 cycles in the superior direction, the mean micromotion was 54 microm (SD, 22) in the control group, 159 microm (SD, 70) in the second group, and 86 microm (SD, 32) in the third group (P = 0.003). Fixing the posterior screw into the spine of the scapula and directing the anterior screw below the central peg decreased the micromotion of a metal glenoid implant fixed in a glenoid with a cavitary defect by 46% and, more importantly, reduced the micromotion below the critical threshold of 150 microm, which is necessary for bone ingrowth and long-term survival of the implant.

Bone grafting for glenoid bone deficiencies in shoulder arthritis: a review

Bone loss in the glenoid in the face of shoulder arthritis can be managed in selected cases with bone grafting. This article reviews the literature and uses this clinical experience to make recommendations for the surgical management of glenoid bone loss in cases of osteopenia, dysplasia, bone loss created by the arthritis, and loss that occurs in the glenoid related to failed shoulder arthroplasty.