Introduction. A 6cm femoral gain requires 5-Y during normal growth, but only 6–8-W surgically (x30–40 faster). In lengthening surgery, losses of muscle force (MF) and circumferences (MC) are major. Recovery is long, preventing sports till bone fusion. Can we maintain MC and strength throughout the entire lengthening and how?. We monitored for over 30 years patients for muscle force (isokinetic), circumferences, activities (including sports) and food intake, and acted on the 5 principles of the Osteostasis. Materials & Methods. Over 750 femoral lengthening with Full WB Nails (FWBN) got Isokinetic testing (≧1991), circumferences measurements (≧2012; 20-15-10-5-0cm above patella, max-calf, mini/max-ankle), food intake (≧2012), using MyFitnessPal App (≧2016), gradually enforced. Preoperative training along with a daily post-operative training are supervised by our trainers. Recommendations for food intake and activities were provided. Patients noted on a specific App all parameters. Compliance was noted. Results. Instead of a traditional 7–9cm circumference loss for 8–10cm gains using Ex-fix or nails, with FWBN and our protocols, no MC loss could be noted in compliant pre-trained patients, intensive early post-op resistance training, high calory intake (M:>4200, F:>3000; 20–25% Proteins) and supplements (no fat pad increase). Bone fusion could be obtained at the end of lengthening or within short weeks (Healing Index down to 8D/cm). Non-compliant patients (or using morphine), lost weight and MC. Conclusions. Increasing by 8–10cm muscle length, even bilaterally, and maintaining MC during lengthening, is possible, with very fast bone fusion. It requires building up several hundred of grams of muscles. The ‘building up equation’ associating resistance bike from the early post-operative phase with sports, strong food intake with increased protein intake, and added supplements with no morphine medication, proved to boost circumferences and bone fusion. It induced fast recovery, walking and sports capacities

Polyetheretherketone (PEEK) interbody fusion cages combined with autologous bone graft is the current clinical gold standard treatment for spinal fusion, however, bone graft harvest increases surgical time, risk of infection and chronic pain. We describe novel low-stiffness 3D Printed titanium interbody cages without autologous bone graft and assessed their biological performance in a pre-clinical in vivo interbody fusion model in comparison to the gold standard, PEEK with graft. Titanium interbody spacers were 3D Printed with a microporous (Ti1: <1000μm) and macroporous (Ti2: >1000μm) design. Both Ti1 and Ti2 had an identical elastic modulus (stiffness), and were similar to the elastic modulus of PEEK. Interbody fusion was performed on L2-L3 and L4-L5 vertebral levels in 24 skeletally mature sheep using Ti1 or Ti2 spacers, or a PEEK spacer filled with iliac crest autograft, and assessed at 8 and 16 weeks. We quantitatively assessed bone fusion, bone area, mineral apposition rate and bone formation rate. Functional spinal units were biomechanically tested to analyse range of motion, neutral zone, and stiffness. Results: Bone formation in macroporous Ti2 was significantly greater than microporous Ti1 treatments (p=.006). Fusion scores for Ti2 and PEEK demonstrated greater rates of bone formation from 8 to 16 weeks, with bridging rates of 100% for Ti2 at 16 weeks compared to just 88% for PEEK and 50% for Ti1. Biomechanical outcomes significantly improved at 16 versus 8 weeks, with no significant differences between Ti and PEEK with graft. This study demonstrated that macroporous 3D Printed Ti spacers are able to achieve fixation and arthrodesis with complete bone fusion by 16 weeks without the need for bone graft. These significant data indicate that low-modulus 3D Printed titanium interbody cages have similar performance to autograft-filled PEEK, and could be reliably used in spinal fusion avoiding the complications of bone graft harvesting

Aim. External fixator knee arthrodesis is a salvage procedure mainly used in cases of end-stage infected total knee replacement (iTKR). A stable fixation combined with bone-ends compression is basic to achieve knee fusion in such a scenario but providing enough stability can be challenging in the presence of severe bone loss after multiple previous procedures. Compared with monoplanar configuration, a biplanar frame achieves improved coronal stiffness, while providing the advantages of good access to the wound and allowance of early ambulation. Our primary hypothesis stated that a biplanar frame would achieve higher and quicker fusion rate than a monolateral configuration. Method. We conducted a retrospective cohort study examining patients managed with biplanar external fixator knee fusion due to non-revisable iTKR between 2014 and 2018. We compared this group of patients with a historical cohort-control patient who had been previously published by our unit in 2013, since we switched from a monoplanar to a biplanar configuration for the management of this kind of complex end-stage iTKR. Primary end-points were fusion rate, time to achieve bone fusion and infection eradication rate. Limb-length discrepancy, pain level, patient satisfaction, and health-related quality of life were also evaluated. Results. A total of 29 cases were finally included; 8 patients were managed with a bilateral external fixator and 21 patients were managed with a monoplanar external fixator. In the biplanar configuration group, infection was eradicated in 100% of the patients, and fusion was achieved in all cases after 5.24 months on average. In comparison, in the monolateral configuration group, infection was eradicated in 18 (86%) out of 21, whereas fusion was achieved in 17 (81%) of the patients after a mean of 10.3 months (range, 4–16). Such difference was statistically significant (p<0.05). In both groups, postoperative pain was mild (VAS score 2,25 and 3,4, respectively) and patients expressed a high degree of satisfaction once fusion was achieved. Conclusions. External fixation knee fusion is a useful limb-salvage procedure in end-stage cases of knee PJI. According to our data, the use of a biplanar configuration allows us to reduce in half (10.3 vs 5.2 months, p<0.05) the time needed to achieve the solid bone fusion in such a complex scenario. In this cohort of previously multi-operated patients, the satisfaction is high, and the level of pain is low if a solid bone fusion free of infection is achieved

Introduction: The mechanobiology and response of bone formation to strain under physiological loading is well established, however investigation into exceedingly soft scaffolds relative to cancellous bone is limited. In this study we designed and 3D printed mechanically-optimised low-stiffness implants, targeting specific strain ranges inducing bone formation and assessed their biological performance in a pre-clinical in vivo load-bearing tibial tuberosity advancement (TTA) model. The TTA model provides an attractive pre-clinical framework to investigate implant osseointegration within an uneven loading environment due to the dominating patellar tendon force. A knee finite element model from ovine CT data was developed to determine physiological target strains from simulated TTA surgery. We 3D printed low-stiffness Ti wedge osteotomy implants with homogeneous stiffness of 0.8 GPa (Ti1), 0.6 GPa (Ti2) and a locally-optimised design with a 0.3 GPa cortex and soft 0.1 GPa core (Ti3), for implantation in a 12-week ovine tibial advancement osteotomy (9mm). We quantitatively assessed bone fusion, bone area, mineral apposition rate and bone formation rate. Optimised Ti3 implants exhibited evenly high strains throughout, despite uneven wedge osteotomy loading. We demonstrated that higher strains above 3.75%, led to greater bone formation. Histomorphometry showed uniform bone ingrowthin optimised Ti3 compared to homogeneous designs (Ti1 and Ti2), and greater bone-implant contact. The greatest bone formation scores were seen in Ti3, followed by Ti2 and Ti1. Results from our study indicate lower stiffness and higher strain ranges than normally achieved in Ti scaffolds stimulate early bone formation. By accounting for loading environments through rational design, implants can be optimised to improve uniform osseointegration. Design and 3D printing of exceedingly soft titanium orthopaedic implants enhance strain induced bone formation and have significant importance in future implant design for knee, hip arthroplasty and treatment of large load-bearing bone defects

Introduction. Frame HI is the #Days for device removal/cm. IM Nail HI is less relevant (31–45 D/cm). Albizzia HI was 33 D/cm (1991–2003). Patients felt fine approximately 1M after end of lengthening (EoL), resuming normal life and sports. This sometimes resulted in implants fractures (e.g. skying before bone fusion). Ideally, the full fusion should occur at the EoL. We decided to shorten the HI to reach this target, optimising all parameters. Materials & Methods. The evolution of care has been monitored over a 32-year clinical experience with a fully weight-bearing nails (Albizzia then G-nail). Monitoring was with X-rays, DEXA, blood bone activity, and in London with special 5G CBCT Scans. We implemented several changes in the Care of patients and measured them according to the ‘Five Principles’ (stability, function, ‘Roads-vascular supply’, ‘Materials-calories’ and ‘Workers-BFC’, with actions on food intake, activity levels and on muscle and bone vascular growths. Results. Preop: training (vascularity, muscle force). Op & Postop: spine morphine, IM sawing preserving BFC, controlled hypo-pressure, low hydration, 50 cm leg elevation, walking, resistance bike, full motion (drainage, muscle reactivation), discharge 3–4h postop (including bilateral). Postop daily intense gym training. POD07-21: Distraction increased to fight non-linear hyper-ossification (44–50 mm gain at POD30) +/- aided by NSAIDs. HI decreased to 12–20D/cm, sometimes 8D/cm with some ‘soft fusion’ during lengthening, hardening within 1W after EoL. Conclusions. The surgeon is not a passive X-rays observer, but has an active role in changing the healing speed and decreasing HI for patient safety. Electro/Magnetic nails (torque 1 Nm) may be clocked by bone fusion, which does not occur with the G-Nail (19 Nm). An holistic vision for patients and treatments at several levels is essential to accelerate bone healing, and to return fast to full normal life, after a short ‘lengthening parenthesis’

Aim. Prosthetic joint infections (PJI) after failed knee arthroplasty, especially in complicated courses with persisting or recurrent infections, may result in a considerable destruction of bone substance, the extensor apparatus and the surrounding soft tissue. In these cases reconstruction of a proper knee function may be impossible and the only solutions are: knee arthrodesis or above-the-knee amputation (AKA). However, both methods are associated with considerable functional deficits and high complication rates. The primary aim of the current study is to analyse the clinical course, outcome and complications in patients with knee arthrodesis and AKA after PJI and to compare these two methods in terms of the analysed parameters. Method. Patients treated with a knee arthrodesis or AKA after PJI in an 11-year time period were included in this study. Demographic data, comorbidities, infecting characteristics and operative procedures were recorded. Patients were seen in regular intervals and underwent physical and radiographic examination. Major complications such as: re-infection, implant-failure, revision surgeries or stump healing disorders were recorded. Functional outcome with use of the Lower-Extremity-Functional-Score was assessed and the patients reported general health status (SF-12-questionnaire) was recorded. Results. In total 87 patients with a knee arthrodesis and 32 patients with an AKA after PJI were included. Knee arthrodesis was performed in 81 patients with a modular system and in six cases with bone fusion. Re-arthrodesis had to be performed in 21 cases. Survival rate of knee arthrodesis was 86% after one year, 71% after five and 61% after ten years. Major complications such as recurrence of infection (n=16) implant loosening (n=12), implant failure (n=3) or per-implant fracture (n=5) occurred in 30% of the patients. In seven patients an amputation after failed arthrodesis had to be performed. In patients with AKA after PJI a similar complication rate of 34% (p=0.64) was seen. Recurrence of infection was diagnosed in nine patients and a re-amputation had to be performed in four cases. The final functional examination was assessed after a mean interval of 48 month and revealed comparably in both cohorts a comparable limitation of functionality (p=0.181) and a slightly worse physical quality of life after knee arthrodesis compared to patients with AKA (p=0.08). Conclusions. Knee arthrodesis or above the knee amputation after PJIshow similar functional limitations and comparably high complication rates. The patients have to be supervised by an interdisciplinary team to avoid complications and regain quality of life

Hind foot Charcot deformity is a disastrous complication of diabetic neuropathy and can lead to instability, ulceration and amputation. The treatment of these patients is controversial. Internal stabilisation and external fixation have demonstrated variable results of limb salvage and some authorities thus advise patients to undergo elective amputation. We report a series of 9 diabetic patients with severe hind foot deformity complicated by ulceration in 5/9, who underwent acute corrective internal fixation with successful correction of deformity, healing of ulceration in 4/5 patients and limb salvage in all cases. Conservative measures such as total contact casting were tried in 5 patients had predominant varus deformity, 2 with valgus deformity and 2 with unstable ankle joints. 5 patients had developed secondary ulceration. All patients underwent corrective hind foot fusion with tibio-talo-calcaneal arthrodesis using a retrograde intramedullary nail fixation and screws and bone grafting. One patient also with fixed planovalgus deformity of the foot underwent a corrective midfoot reconstruction. Patients were followed up in a diabetic/orthopaedic multidisciplinary foot clinic and were treated with total contact casting. (Mean follow up time was 15.6 ±6.9months) In all patients the deformity was corrected with successful realignment to achieve a plantigrade foot. Healing of the secondary ulcers was achieved in 4/5 cases and limb salvage was achieved in all cases. Three patients underwent further surgical procedure to promote bone fusion. One patient required removal of a significantly displaced fixation screw. Two patients had postoperative wound infections which that were treated with initially intravenous antibiotic therapy and then negative pressure wound therapy. In conclusion, internal fixation for severe hind foot deformity together with close follow up in a multidisciplinary diabetic/orthopaedic foot clinic can be successful in diabetic patients with advanced Charcot osteoarthropathy and secondary ulceration

Introduction. Hind foot Charcot deformity is a disastrous complication of diabetic neuropathy and can lead to instability, ulceration and major amputation. The treatment of these patients is controversial. Internal stabilization and/or external fixation have demonstrated variable results of limb salvage and some authorities thus advise patients to undergo elective major amputation. However, we report a series of 9 diabetic patients with severe hind foot deformity complicated by ulceration in 5/9, who underwent acute corrective internal fixation with successful correction of deformity, healing of ulceration in 4/5 patients and limb salvage in all cases. Methods. We treated 9 diabetic patients attending a multidisciplinary diabetic/orthopaedic foot clinic with progressive severe Charcot hind foot deformity despite treatment with total contact casting, 5 with predominant varus deformity and 2 with valgus deformity and 2 with unstable ankle joints. Five patients had developed secondary ulceration. All patients underwent corrective hind foot fusion with tibiotalo-calcaneal arthrodesis using a retrograde intra-medullary nail fixation and screws and bone grafting. One patient also with fixed plano-valgus deformity of the foot underwent a corrective mid-foot reconstruction. Results. Patients were followed up closely in the diabetic /orthopaedic multidisciplinary foot clinic and were treated with total contact casting. (Mean follow up time was 15.6 ±6.9months) In all patients the deformity was corrected with successful realignment to achieve a plantigrade foot. Healing of the secondary ulcers was achieved in 4/5casesand limb salvage was achieved in all cases. Three patients underwent further surgical procedure to promote bone fusion. One patient required removal of a significantly displaced fixation screw. In another patient with previously existing heel ulceration, the fixation device was removed due to progressive ulceration. However, by then, the patient had achieved fibrous union and stability of the hind foot. Two patients had postoperative wound infections which that were treated with initially intravenous antibiotic therapy and then negative pressure wound therapy. Conclusion. In conclusion, internal fixation for severe hind foot deformity together with close follow up in a multidisciplinary diabetic/orthopaedic foot clinic can be successful in diabetic patients with advanced Charcot osteoarthropathy and secondary ulceration