It is essential that the complex biological processes related to bone immunogenicity are understood, since this may allow the development of safer and more successful ways of controlling the outcome of bone allografting.

The 'law of diminishing returns' is also seen after serial distraction using MCGR. Compared to previously published data for CGRS, there is a gradual linear decline rather than a rapid initial decline in lengthening. In older, heavier children a reduced distraction ratio in the concave rod of the MCGR device is noted over time. Cite this article: 2017;99-B:1658-64.

We report a retrospective review of the outcome of treatment of 202 periprosthetic fractures around total hip arthroplasty (THA) from two specialised arthroplasty centres. Fractures were classified according to the Vancouver classification. The aim was to evaluate treatment methods with respect to stem revision and grafting. Transverse B1 fractures treated with stem revision compared to those treated with open reduction and internal fixation (ORIF) with a plate showed a trend towards improved overall union rate (OR=2, p=0.6, 95% CI:0.14-28.4) and shorter times to union (p=0.038, mean 12 months SD 6.573 for ORIF versus 4.48 months SD 0.757 for stem revision). B2 fractures undergoing stem revision and grafting were significantly more likely to unite compared to ORIF alone (OR=17.3, p=0.018 95%CI:1.63-184.4). B3 fractures presented with significant variation in fracture configuration and bone loss and therefore their treatment was individualised. When treated with stem revision and grafting healing was achieved in a mean time of 7 months (n=81). Periprosthetic fractures of the femur are highly complex and challenging. Stem revision for transverse B1 fractures is now considered as a viable treatment modality as this fracture configuration is difficult to control with single plating, and fixation with a long stem bypassing the distal fracture line is necessary to achieve axial stability and healing. Bone allografting, whether used as a cortical onlay or in morselised impacted form for B2 and B3 fractures enhances fracture healing.

Study Design  Narrative review.Objective  The study aims to critically review the outcomes associated with the surgical repair or conservative management of spondylolysis in athletes.Methods  The English literature listed in MEDLINE/PubMed was reviewed to identify related articles using the term “spondylolysis AND athlete.” The criteria for studies to be included were management of spondylolysis in athletes, English text, and no year, follow-up, or study design restrictions. The references of the retrieved articles were also evaluated. The primary outcome was time to return to sport. This search yielded 180 citations, and 25 publications were included in the review.Results  Treatment methods were dichotomized as operative and nonoperative. In the nonoperative group, 390 athletes were included. A combination of bracing with physical therapy and restriction of activities was used. Conservative measures allowed athletes to return to sport in 3.7 months (weighted mean). One hundred seventy-four patients were treated surgically. The most common technique was Buck's, using a compression screw (91/174). All authors reported satisfactory outcomes. Time to return to play was 7.9 months (weighted mean). There were insufficient studies with suitably homogenous subgroups to conduct a meta-analysis.Conclusion  There is no gold standard approach for the management of spondylolysis in the athletic population. The existing literature suggests initial therapy should be a course of conservative management with thoracolumbosacral orthosis brace, physiotherapy, and activity modification. If conservative management fails, surgical intervention should be considered. Two-sided clinical studies are needed to determine an optimal pathway for the management of athletes with spondylolysis.