Introduction. A significant burden of disease exists with respect to critical sized bone defects; outcomes are unpredictable and often poor. There is no absolute agreement on what constitutes a “critically-sized” bone defect however it is widely considered as one that would not heal spontaneously despite surgical stabilisation, thus requiring re-operation. The aetiology of such defects is varied. High-energy trauma with soft tissue loss and periosteal stripping, bone infection and tumour resection all require extensive debridement and the critical-sized defects generated require careful consideration and strategic management. Current management practice of these defects lacks consensus. Existing literature tells us that tibial defects 25mm or great have a poor natural history; however, there is no universally agreed management strategy and there remains a significant evidence gap. Drawing its origins from musculoskeletal oncology, the Capanna technique describes a hybrid mode of reconstruction. Mass allograft is combined with a vascularised fibula autograft, allowing the patient to benefit from the favourable characteristics of two popular reconstruction techniques. Allograft confers initial mechanical stability with autograft contributing osteogenic, inductive and conductive capacity to encourage union. Secondarily its inherent vascularity affords the construct the ability to withstand deleterious effects of stressors such as infection that may threaten union. The strengths of this hybrid construct we believe can be used within the context of critical-sized bone defects within tibial trauma to the same success as seen within tumour reconstruction. Methodology. Utilising the Capanna technique in trauma requires modification to the original procedure. In tumour surgery pre-operative cross-sectional imaging is a pre-requisite. This allows surgeons to assess margins, plan resections and order allograft to match the defect. In trauma this is not possible. We therefore propose a two-stage approach to address critical-sized tibial defects in open fractures. After initial debridement, external fixation and soft tissue management via a combined orthoplastics approach, CT imaging is performed to assess the defect geometry, with a polymethylmethacrylate (PMMA) spacer placed at index procedure to maintain soft tissue tension, alignment and deliver local antibiotics. Once comfortable that no further debridement is required and the risk of infection is appropriate then 3D printing technology can be used to mill custom jigs. Appropriate tibial allograft is ordered based on CT measurements. A pedicled fibula graft is raised through a lateral approach. The peroneal vessels are mobilised to the tibioperoneal trunk and passed medially into the bone void. The cadaveric bone is prepared using the custom jig on the back table and posterolateral troughs made to allow insertion of the fibula, permitting some hypertrophic expansion. A separate medial incision allows attachment of the custom jig to host tibia allowing for reciprocal cuts to match the allograft. The fibula is implanted into the allograft, ensuring nil tension on the pedicle and, after docking the graft, the hybrid construct is secured with multi-planar locking plates to provide rotational stability. The medial window allows plate placement safely away from the vascular pedicle. Results. We present a 50-year-old healthy male with a Gustilo & Anderson 3B proximal tibial fracture, open posteromedially with associated shear fragment, treated using the Capanna technique. Presenting following a fall climbing additional injuries included a closed ipsilateral calcaneal and medial malleolar fracture, both treated operatively. Our patient underwent reconstruction of his tibia with the above staged technique. Two debridements were carried out due to a 48-hour delay in presentation due to remote geographical location of recovery. Debridements were carried out in accordance with BOAST guidelines; a spanning knee external fixator applied and a small area of skin loss on the proximal medial calf reconstructed with a split thickness skin graft. A revision cement spacer was inserted into the metaphyseal defect measuring 84mm. At definitive surgery the external fixator was removed and graft fixation was extended to include the intra-articular fragments. No intra-operative complications were encountered during surgeries. The patient returned to theatre on day 13 with a medial sided haematoma. 20ml of haemoserous fluid was evacuated, a DAIR procedure performed and antibiotic-loaded bioceramics applied locally. Samples grew Staphylococcus aureus and antibiotic treatment was rationalised to Co-Trimoxazole 960mg BD and Rifampicin 450mg BD. The patient has completed a six-week course of Rifampicin and continues on suppressive Co-Trimoxazole monotherapy until planned metalwork removal. There is no evidence of ongoing active infection and radiological evidence of early union. The patient is independently walking four miles to the gym daily and we believe, thus far, despite accepted complications, we have demonstrated a relative early success. Conclusions. A variety of techniques exist for the management of critical-sized bone defects within the tibia. All of these come with a variety of drawbacks and limitations. Whilst acceptance of a limb length discrepancy is one option, intercalary defects of greater than 5 to 7cm typically require reconstruction. In patients in whom fine wire fixators and distraction osteogenesis are deemed inappropriate, or are unwilling to tolerate the frequent re-operations and potential donor site morbidity of the Masqualet technique, the Capanna technique offers a novel solution. Through using tibial allograft to address the size mismatch between vascularised fibula and tibia, the possible complication of fatigue fracture of an isolated fibula autograft is potentially avoidable in patients who have high functional demands. The Capanna technique has demonstrated satisfactory results within tumour reconstruction. Papers report that by combining the structural strength of allograft with the osteoconductive and osteoinductive properties of a vascularised autograft that limb salvage rates of greater than 80% and union rates of greater than 90% are achievable. If these results can indeed be replicated in the management of critical-sized bone defects in tibial trauma we potentially have a treatment strategy that can excel over the more widely practiced current techniques

Introduction. Reconstruction of large defect of tibia following infection is considered as one of the most difficult problem facing the orthopaedic surgeon. Amputation with modern prosthetic fitting is a salvage procedure to treat big defects, which gives a functional result with unpredictable psychological impact. Materials & Methods. Between January 2000 and January 2021, 56 patients (30 males and 26 females) with big defects following infection and post traumatic injury of the tibia were treated. The mean age of the patients at the time of surgery was 20.5 years (4–24 years). The fibula was mobilized medially to fill the defect and was fixed with Ilizarov fixator. The average size of the defects reconstructed was 18.5 cm (17–20 cm). Results. The average time for complete union was 8.6 months (range, 5–9 months). At final follow-up all patients had fully united. We found leg length discrepancy in 52 patients and that was corrected by re-lengthening of the solid new regenerate bone. Conclusions. The Ilizarov method has been shown to be an effective method of treating Tibialization of fibula for reconstruction of big tibial defects

Introduction. Aneurysmal bone cysts commonly found in lower limbs are locally aggressive masses that can lead to bony erosion, instability and fractures. This has major implications in the lower limbs especially in paediatric patients, with potential growth disturbance and deformity. In this case series we describe radical aneurysmal bone cyst resection and lower limb reconstruction using cable transport and syndesmosis preservation. Materials & Methods. Case 1 - A 12-year-old boy presented with a two-week history of atraumatic right ankle pain. An X-ray demonstrated a distal tibia metaphyseal cyst confirmed on biopsy as an aneurysmal bone cyst. The cyst expanded on interval X-rays from 5.5cm to 8.5cm in 9 weeks. A wide-margin en-bloc resection was performed leaving a 13.8cm tibial defect. A cable transport hexapod frame and a proximal tibial osteotomy was performed, with syndesmosis screw fixation. The transport phase lasted 11 months. While in frame, the boy sustained a distal femur fracture from a fall. The femur and the docking site were plated at the same sitting and frame removed. At one-year post-frame removal he is pain-free, with full ankle dorsiflexion but plantarflexion limited to 25 degrees. He has begun graduated return to sport. Results. Case 2 - A 12-year-old girl was referred with a three-month history of lateral left ankle swelling. X-ray demonstrated an aneurysmal bone cyst in the distal fibula metaphysis. The cyst grew from 4.2 × 2.3cm to 5.2 × 3.32cm in 2 months. A distal fibula resection (6.2cm) with syndesmosis fixation and hexapod cable transport frame were undertaken. The frame was in situ for 13 weeks and during this time she required an additional osteotomy for premature consolidation and had one pin site infection. After 13 weeks a second syndesmosis screw was placed, frame removed, and a cast applied. 3 months later she had fibular plating, BMAC and autologous iliac crest bone graft for slow union. At 3 years post-operative she has no evidence of recurrence, is pain-free and has no functional limitation. Conclusions. We describe two cases of ankle syndesmosis preservation using cable transport for juxta-articular aneurysmal bone cysts. This allows wide resection to prevent recurrence while also preserving primary ankle stability and leg length in children. Both children had a minor complication, but both had an excellent final outcome. Cable bone transport and prophylactic syndesmosis stabilization allows treatment of challenging juxta-articular aneurysmal bone cysts about the ankle. These techniques are especially useful in large bone defects

Introduction. Bone transport and distraction osteogenesis have been shown to be an effective treatment for significant bone loss in the tibia. However, traditional methods of transport are often associated with high patient morbidity due to the pain and scarring caused by the external frame components transporting the bone segment. Prolonged time in frame is also common as large sections of regenerate need significant time to consolidate before the external fixator can be removed. Cable transport has had a resurgence with the description of the balanced cable transport system. However, this introduced increasingly complex surgery along with the risk of cable weave fracture. This method also requires frame removal and intramedullary nailing, with a modified nail, to be performed in a single sitting, which raised concern regarding potential deep infection. An alternative to this method is our modified cable transport system with early intramedullary nail fixation. Internal cables reduce pain and scarring of the skin during transport and allow for well controlled transport segment alignment. The cable system is facilitated through an endosteal plate that reduces complications and removes the need for a single-stage frame removal and nailing procedure. Instead, the patients can undergo a pin-site holiday before nailing is performed using a standard tibial nail. Early intramedullary nailing once transport is complete reduces overall time in frame and allows full weight bearing as the regenerate consolidates. We present our case series of patients treated with this modified cable transport technique. Methodolgy. Patients were identified through our limb reconstruction database and clinic notes, operative records and radiographs were reviewed. Since 2019, 8 patients (5 male : 3 female) have undergone bone transport via our modified balanced cable transport technique. Average age at time of transport was 39.6 years (range 21–58 years) with all surgeries performed by the senior author. Patients were followed up until radiological union. We recorded the length of bone transport achieved as well as any problems, obstacles or complications encountered during treatment. We evaluated outcomes of full weight bearing and return to function as well as radiological union. Results. 4/8 bone defects were due to severely comminuted open fractures requiring extensive debridement. All other cases had previously undergone fixation of tibial fractures which had failed due to infection, soft tissue defects or mal-reduction. The mean tibial defect treated with bone transport was 41mm (range 37–78mm). From the start of cable transport to removal of external fixator our patients spent an average of 201 days in frame. 7/8 patients underwent a 2-week pin-site holiday and subsequent insertion of intramedullary nail 2 weeks later. One patient had sufficient bony union to not require further internal fixation after frame removal. 10 problems were identified during treatment. These included 4 superficial infections treated with antibiotics alone and 5 issues with hardware, which could be resolved in the outpatient clinic. 1 patient had their rate of transport slowed due to poor skin quality over the site of the regenerate. 4 obstacles resulted in a return to theatre for additional procedures. 1 patient had a re-do corticotomy and 3 had revision of their internal cable transport constructs due to decoupling or screw pull out. 1 patient had residual ankle joint equinus following treatment which required an Achilles tendon lengthening procedure. Another patient underwent treatment for DVT. There were no deep infections identified and no significant limb length discrepancies or deformities. Conclusions. Overall, we have found that our modified balanced cable transport technique has allowed for successful bone transport for significant defects of the tibia. We have learned from the obstacles encountered during this case series to avoid unnecessary return trips to theatre for our future transport patients. The internal cable system allowed all patients to complete their planned transport without excessive pin tract scarring or pain. Early conversion to intramedullary nail allowed for a shorter time in frame with continued full weight bearing as the regenerate consolidated. No metalwork failure or deformity has occurred in relation to docking site union. All patients have made a good return to pre-operative function during their follow-up period with no evidence of late complications such as deep infection

Introduction. Various methods to manage medial tibial defects in primary total knee arthroplasty (TKA) have been described. According to Vail TP, metal augmentation is usually indicated for defect depth of >10 mm of the medial tibial plateau. The outcomes of metal augmentation have been described as excellent. Nevertheless, we believe that it is mandatory to preserve as much of the bone as possible for future revision surgeries. Therefore, we performed autologous impaction bone grafting even for large bone defects (defect depth of ≥10 mm) in primary TKA. The objectives of this study are to describe our bone grafting technique in detail and to assess the radiological outcomes of the grafted bone. Methods. Between 2003 and 2011, 26 TKAs with autologous impaction bone grafting for ≥10 mm medial tibial defects were performed. The preoperative diagnoses were osteoarthritis in 17 knees, rheumatoid arthritis in 2 knees, osteonecrosis of the medial tibial condyle in 6 knees, and Charcot's joint in 1 knee. The average mediolateral width and depth of the medial tibial defects, measured after the horizontal osteotomy of the tibial articular surface, were 17.8 mm (range, 10–25 mm) and 12.0 mm (range, 10–23 mm), respectively. The average patient age at surgery was 73.2 years (range, 56–85 years). The patients were followed up for an average of 55 months (range 27–109 months). Bone grafting technique: Multiple drill holes (white arrow) were made on the floor of the defect (A) and a morselized cancellous bone was impacted using the grip end of a metal hammer (white asterisk) and firm manual pressure to fill the defect. Thus, the firm impaction prevented bone cement from entering the space between the graft and the tibial host bed. An assistant's index finger (black asterisk) was used as a bank (B). The tibial component was fixed on the grafted bone (white asterisk) with bone cement (C). Internal fixation devices were not required, and stem extension was used in only Charcot's joint (defect depth=23 mm). Aftertreatment was the same as that for the usual TKAs without bone defects. Results. In terms of clinical outcomes, no patient showed disturbances in walking ability at final follow-up. The average knee flexion angle was 114° (range, 95°–130°). The grafted bone was kept at the grafted area on the radiograms throughout the follow-up period. No absorption or collapse of the grafted bone was observed on the radiograms at the final follow-up. Usually, the grafted bone showed osteosclerotic changes around 2–3 months after TKA. Then, the osteosclerosis became weakened and the bony trabeculae could be detected in the grafted area. Finally, the grafted bone completely incorporated into the host bone in all knees with evidence of bony trabeculae crossing the interface by up to 1 year after surgery. The margin of the grafted area resembled bony cortex in 19 TKAs (73.1%). Conclusions. Our technique is easy, economic, and reproducible. It is an acceptable alternative to metal augmentation for large medial tibial defects in primary TKA

The management of bone loss in revision total knee replacement (TKA) remains a challenge. To accomplish the goals of revision TKA, the surgeon needs to choose the appropriate implant design to “fix the problem,” achieve proper component placement and alignment, and obtain robust short- and long-term fixation. Proper identification and classification of the extent of bone loss and deformity will aid in preoperative planning. Extensive bone loss may be due to progressive osteolysis (a mechanism of failure), or as a result of intraoperative component removal. The Anderson Orthopaedic Research Institute (AORI) is a useful classification system that individually describes femoral and tibial defects by the appearance, severity, and location of bone defects. This system provides a guideline to treatment and enables preoperative planning on radiographs. In Type 1 defects, femoral and tibial defects are characterised by minor contained deficiencies at the bone-implant interface. Metaphyseal bone is intact and the integrity of the joint line is not compromised. In this scenario, the best reconstruction option is to increase the thickness of bone resection and to fill the defect with cancellous bone graft or cement. Type 2 defects are characterised by deficient metaphyseal bone involving one or more femoral condyle(s) or tibial plateau(s). The peripheral rim of cortical bone may be intact or partially compromised, and the joint line is abnormal. Reconstruction options for a Type 2A defect include impaction bone grafting, cement, or more commonly, prosthetic augmentation (e.g. sleeves, augments or wedges). In Type 2B defects, metaphyseal bone of both femoral condyles or both tibial plateaus is deficient. The peripheral rim of cortical bone may be intact or partially compromised, and the joint line is abnormal. Options for a Type 2B defect include impaction grafting, bulk structural allograft, prosthetic augmentation, metaphyseal sleeves (in some cases), or metaphyseal cones. Finally, in the presence of a Type 3 deficiency, both metaphyseal and cortical bone is deficient and there is partial or complete disruption of the collateral ligament attachments. In this case, the most commonly used reconstruction options include hinged implants or megaprostheses with or without bulk structural allograft, prosthetic augmentation, and/or metaphyseal/diaphyseal sleeves or cones. Today, we are fortunate to have a wide variety of options available to aid in reconstruction of a revision TKA with massive bone loss. Historically, use of cement, bone grafting, or use of a tumor-type or hinged implant were considered the main options for reconstruction. The development and adoption of highly porous sleeves and cones has given the surgeon a new and potentially more durable option for reconstruction of previously difficult to treat defects. Using radiographs and computed tomography, surgeons are able to preoperatively classify bone loss and anticipate a reconstruction plan based upon the classification; however, it is always important to have several back-up options on hand during revision surgery in the event bone loss is worse than expected

Introduction. Circular frame fixation has become a cornerstone of non-union and deformity management since its inception in the 1950s. As a consequence of modularity and heterogenous patient and injury factors, the prediction of the mechanobiological environment within a defect is subject to wide variations in practice. Given these wide range of confounding variables, clinical and cadaveric experimentation is close to impossible and frame constructs are based upon clinician experience. The Finite Element Analysis (FEA) method provides a powerful tool to numerically analyse mechanics. This work aims to develop an FEA model of a tibial defect and predict the mechanical response within the construct. Materials and Methods. The geometry of a tibia was acquired via CT and a series of bone defects were digitally created in the tibial diaphysis. A 4-ring, 10-wire Ilizarov fixator was constructed using 180mm stainless steel rings and 1.8mm stainless steel wires tensioned to 1200N. An axial load (800N) was applied to simulate single leg stance of an 80kg patient. The magnitude of displacement was measured for defects with varying sizes (5–40mm). A numerical analysis was performed in large-strain regime using open-source FEA library (MoFEM). Results. Defect size did not effect displacement, but significantly influenced strain. Measured displacements were 5.72–5.78mm, however strain ranged from 14.5–100%. Moreover, it was found that bone material properties also have no significant impact on the results. Conclusions. Accounting for FEA assumptions, this model predicted a strain environment which was above expected favourable range for bone healing. The addition of graft within the environment is likely to change the mechanobiological environment which warrants further investigation. We plan to develop this model to answer further research questions in the limb reconstruction discipline and validate its accuracy with mechanical data. We believe the presented approach can be a useful tool for investigating the performance circular frames

Osteolysis commonly causes total knee replacement (TKR) failure, often associated with asymptomatic large defects. Detection and size estimation of lytic defects is important for the indications and planning of revision surgery. Our study compares the utility of fluoroscopic-guided plain X-rays and computed topography (CT) in osteolysis detection and volume appreciation. Three cadaveric specimens were imaged at baseline and following the creation of reamed defects (small, medium and large approximately = 1, 5 & 10 cm3 volume respectively) in the tibia and femur with TKR component implantation at each timepoint. Imaging was with fluoroscopic-guided plain X-rays (Anteroposterior & Lateral [APL], Paired Oblique [OBL]) as well as rapid-acquisition spiral Computed Topography [CT] with a beam-hardening artefact removal algorithm. Three arthroplasty surgeons estimated the size of the lesion, if present, and confidence (none=0, fair=1, excellent=2) in their assessment on randomly presented images. Each surgeon performed two assessments of each image one month apart. The accuracy of detecting lesions was determined using the area under the receiver-operating curve (AU-ROC) obtained from a logistic regression with adjustment for assessment sequence, observer, knee and bone. Volume appreciation and assessor confidence were determined using Kappa and the mean average of confidence scores respectively. The AU-ROC using combinations of either APL/OBL/CT (0.83) or OBL/CT (0.83) resulted in superior detection of lesions (p<0.05) compared to APL (0.75) or OBL alone (0.77). Correct volume appreciation was highest with APL/OBL/CT (kappa=0.52), followed by APL/OBL (0.51) and was superior (p<0.05) to APL (0.29) or CT alone (0.31). Small and medium defects were more often missed than large with all modalities (20.3 vs. 39.7 %). Femoral defects were missed more often than tibial defects (40% vs. 28.7%) and small lesions missed more with CT (50%) versus APL (48%) and Oblique (40%). CT missed 19% of large sized defects, attributed mostly to femoral (29.1%) rather than tibial defects (8.3%). Greater confidence was derived from use of CT (1.29) and APL (1.19) [Interquartile range (IQR) 1,2] when compared to OBL (.98, IQR 1,1) [p<.01]. Also, there was greater confidence regarding judgement of tibial defects (1.25, IQR 1,2) compared with femoral defects (1.05, IQR 1,1) [p<.01]. Combining all imaging modalities was synergistic and the most sensitive and specific means of defect detection and volume appreciation. CT provided more confidence, superior detection and volume appreciation when used in combination with APL/OBL versus APL/OBL alone. There is also additional value when APL is combined with OBL

Aim. Simultaneous use of Ilizarov techniques with transfer of free muscle flaps is not current standard practice. This may be due to concerns about duration of surgery, clearance of infection, potential flap failure or coordination of surgical teams. We investigated this combined technique in a consecutive series of complex tibial infections. Method. A single centre, consecutive series of 45 patients (mean age 48 years; range 19–85) were treated with a single stage operation to apply an Ilizarov frame for bone reconstruction and a free muscle flap for soft-tissue cover. All patients had a segmental bone defect in the tibia, after excision of infected bone and soft-tissue defects which could not be closed directly or with local flaps. We recorded comorbidities, Cierny-Mader and Weber-Cech classification, the Ilizarov method used, flap type, follow-up duration, time to union and complications. Results. 26 patients had osteomyelitis and 19 had infected non-union. Staphylococci were cultured in 25 cases and 17 had polymicrobial infections. Ilizarov monofocal compression was used in 14, monofocal distraction in 15, bifocal compression/distraction in 8, and bone transport in 8. 8/45 had an additional ankle fusion, 7/45 had an angular deformity corrected at the same time and 24 also had local antibiotic carriers inserted. Median time in frame was 5 months (3–14). 38 gracilis, 7 latissimus dorsi and 1 rectus abdominus flaps were used. One flap failed within 48 hours and was revised (flap failure rate 2.17%). There were no later flap complications. Flaps were not affected by distraction or bone transport. Mean follow-up was 23 months (10–89). 44/45 (97.8%) achieved bony union. Recurrence of infection occurred in 3 patients (6.7%). Secondary surgery was required to secure union with good alignment in 8 patients (17.8%; docking site surgery in 6, IM nailing in 2) and in 3 patients for infection recurrence. All were infection free at final follow-up. Conclusions. Simultaneous Ilizarov reconstruction with free muscle flap transfer is safe and effective in treating segmental infected tibial defects, and is not associated with an increased flap failure rate. It shortens overall time spent in treatment, with fewer operations per patient. However, initial theatre time is long and a committed multidisciplinary team is required to achieve good results

Introduction. The ability to create patient-specific implants (PSI) at the point-of-care has become a desire for clinicians wanting to provide affordable and customized treatment. While some hospitals have already adopted extrusion-based 3D printing (fused filament fabrication; FFF) for creating non-implantable instruments, recent innovations have allowed for the printing of high-temperature implantable polymers including polyetheretherketone (PEEK). With interest in FFF PEEK implants growing, it is important to identify methods for printing favorable implant characteristics such as porosity for osseointegration. In this study, we assess the effect of porous geometry on the cell response and mechanical properties for FFF-printed porous PEEK. We also demonstrate the ability to design and print customized porous implants, specifically for a sheep tibial segmental defect model, based on CT images and using the geometry of triply periodic minimal surfaces (TPMS). Methods. Three porous constructs – a rectilinear pattern and gyroid/diamond TPMSs – were designed to mimic trabecular bone morphology and manufactured via PEEK FFF. TPMSs were designed by altering their respective equation approximations to achieve desired porous characteristics, and the meshes were solidified and shaped using a CAD workflow. Printed samples were mCT scanned to determine the resulting pore size and porosity, then seeded with pre-osteoblast cells for 7 and 14 days. Cell proliferation and alkaline phosphatase activity (ALP) were evaluated, and the samples were imaged via SEM. The structures were tested in compression, and stiffness and yield strength values were determined from resulting stress-strain plots. Roughness was determined using optical profilometry. Finally, our process of porous structure design/creation was modified to establish a proof-of-concept workflow for creating PSIs using geometry established from segmented sheep tibia CT images. Results. ALP activity measurements of the porous PEEK samples at 7 and 14 days were significantly greater than for solid controls (p < 0.001 for all three designs, 14 days). No difference between the porous geometries was found. SEM imaging revealed cells with flat, elongated morphology attached to the surface of the PEEK and into the pore openings, with filopodia and lamellipodia extensions apparent. mCT imaging showed average pore size to be 545 ± 43 µm (porosity 70%), 708 ± 64 µm (porosity 68%), and 596 ± 94 µm (porosity 69%) for the rectilinear, gyroid, and diamond structures, respectively. The average error between the theoretical and actual values was −16.3 µm (pore size) and −3.3 % (porosity). Compression testing revealed elastic moduli ranging from 210 to 268 MPa for the porous samples. Yield strengths were 6.6 ± 1.2 MPa for lattice, 14.8 ± 0.7 MPa for gyroid, and 17.1 ± 0.6 for diamond. Average roughness ranged from 0.8 to 3 µm. Finally, we demonstrated the ability to design and print a fully porous implant with the geometry of a sheep tibia segment. Assessments of implant geometrical accuracy and mechanical performance are ongoing. Discussion. We created porous PEEK with TPMS geometries via FFF and demonstrated a positive cellular response and mechanical characteristics similar to trabecular bone. Our work offers an innovative approach for advancing point-of-care 3D printing and PSI creation

Introduction. Young, high-demand patients with large post-traumatic tibial osteochondral defects are difficult to treat. Fresh osteochondral allografting is a joint-preserving treatment option that is well-established for such defects. Our objectives were to investigate the long-term graft survivorships, functional outcomes and associated complications for this technique. Methods. We prospectively recruited patients who had received fresh osteochondral allografts for post-traumatic tibial plateau defects over 3cm in diameter and 1cm in depth with a minimum of 5 years follow-up. The grafts were retrieved within 24 hours, stored in cefalozolin/bacitracin solution at 4°C, non-irradiated and used within 72 hours. Tissue matching was not performed but joints were matched for size and morphology. Realignment osteotomies were performed for malaligned limbs. The Modified Hospital for Knee Surgery Scoring System (MHKSS) was used for functional outcome measure. Kaplan-Meier survivorship analysis was performed with conversion to TKR as end point for graft failure. Results. Of 132 patients identified, 14 were lost to follow-up and 37 had less than 5 years follow-up, leaving 81 patients. There were 29 conversions to TKR at a mean of 12 (3-23) years post-operatively. The remaining 52 patients had a mean MHKSS score of 83 (49-100) with a mean follow-up of 11.7 (5-34) years. The Kaplan-Meier graft survivorships were 94% at 5 years (SE 2.7), 83% at 10 years (SE 4.6), 62% at 15 years (SE 7.4) and 45% at 20 years (SE 8.5). Associated complications included infection (1.2%) treated by 2-stage TKR, graft collapse (8.6%) treated by TKR, osteotomy and conservatively and knee pain relieved by hardware removal (7.4%). Conclusion. Fresh osteochondral allograft is a successful treatment option for large post-traumatic tibial osteochondral defects in young patients, with satisfactory long term survivorships and functional outcomes with acceptable complication rates

Introduction. Bone loss in the distal femur and proximal tibia is frequently encountered with both complex primary and revision knee replacement surgery. Metaphyseal sleeves provide a good option for enhanced fixation in managing such defects on both the tibia and femur. We present our results in 48 patients (50 knees) with a minimum 12 month follow up (range 12 to 45). Methods. 48 patients (50 knees) who had revision knee arthroplasty for either septic or aseptic loosening. All were graded Type II or III using the Anderson Orthopaedic Research Institute (AORI) grading system of both femoral and tibial defects. A large portion of aseptic loosening revisions were for extreme osteolysis of a bicondylar knee prosthesis. Results. 52% had tibial sleeves only, 38% had both tibial and femoral sleeves and the remainder had only femoral sleeves inserted. All knee radiographs at final follow-up showed well-fixed osteointegrated components without component migration or clinically significant osteolysis. Two knees were treated with multiple arthroscopic washouts for infection. Two knees subsequently underwent manipulation under anaesthesia with good improvement in range of movement. One subsequently developed Complex Regional Pain Syndrome. No femoral or tibial components were revised. The average pre-operative Oxford Knee Score was 22 (12 to 38) and subsequently improved to 38 (12 to 45) post-operatively. Discussion and conclusions. Our early results show encouraging signs that porous titanium sleeves are a good option when managing large metaphyseal bone loss in both femur and tibia especially in revision arthroplasty. Post operative complications were low and functional outcome scores were comparable with more traditional knee revision arthroplasty techniques in the presence of bone loss

Chronic posttraumatic osteomyelitis (CPTO) is a complex condition that results in considerable morbidity and may be limb threatening. Tibia is the most common site of CPTO, with an average infection rate of 10% for open fractures and 1% for closed fractures. In most cases osteomyelitis is polymicrobial. Staphylococcus aureus is the most common infecting organism present either alone or in combination with other pathogens in 65 to 70% of patients. Adequate soft-tissue coverage is one of the cornerstones in chronic osteomyelitis management. Vacuum-assisted closure (VAC) is frequently used for the treatment of posttraumatic osteomyelitis of the extremities. After debridement and repeated VAC dressing changes, the wounds are closed by secondary suture, split-thickness skin grafts or local flaps. Free muscle flaps are recommended in distal third tibial defects. We present our experience with two case reports. The authors present two cases of type IIIA osteomyelitis according to Cierny-Mader classification, following previous distal third tibial open fractures. Both patients presented with limb deformity, insidious local pain and chronic purulent discharge (without significant local inflammatory signs) after 11 and 24 years of trauma. They were treated with radical debridement of all nonviable and infected tissue, VAC instillation therapy for 3 weeks and transverse rectus abdominis muscle (TRAM) flap defect coverage. Intra-operative cultures were positive for multiple pathogens. Specific antibiotic therapy was performed for each case for 8 weeks. Symptomatic relieve was achieved and C-reactive protein and white blood cell count returned to normal values. No complications were documented. 1 year post-surgery, both patients remain asymptomatic, with no signs of infection, with full flap integrity and gait without assistance. Despite the challenging management of chronic posttraumatic osteomyelitis of the tibia, infection control and a satisfactory functional outcome can be achieved. The cornerstones of management include infection control with surgical debridement, microbial-specific antibiotic administration and soft tissue coverage. VAC instillation therapy has an important role promoting granulation tissue formation and infection eradication. The aggressive approach, even with delay on diagnosis, is the key factor for a worthy outcome. Despite the good results, recrudescence of osteomyelitis is known to occur even years after the original offense is treated

Introduction. The optimal management of severe tibial and/or femoral bone loss in a revision total knee arthroplasty (TKA) has not been established. Reconstructive methods include structural or bulk allografts, impaction bone-grafting with or without mesh augmentation, custum prosthetic components, modular metal augmentations of prosthesis and tumor prosthesis. Recently metaphyseal fixation using porous tantalum cones (Zimmer, Warsaw, IN) has been proposed as alternative strategy for severe bone loss. Objectives. The purposes of this study were to determine the clinical and radiographic outcomes in patients who underwent revision knee arthroplasty with tantalum cones with a minimum of 5-year follow-up. Methods. From November 2005 to August 2008 a total of 26 porous tantalum metaphyseal cones were used to reconstruct severe tibial and/or femoral bone loss in 18 patients during revision TKA at a single institution. There were 12 females and 6 males with an average age of 73 years (range 55–84) at the time of revision. The mean clinical and radiographic follow-up was 6.3 years (range, 5–8). The reasons for revision were aseptic loosening (5 cases) and deep infection (13 cases). A Two stage procedure was used in all septic cases. According to the Anderson Orthopaedic Reseach Institute (AORI) bone defects classification all femoral and tibial defects were rated 2B and 3 (3 T2b, 9 T3, 3 F2b and 10 F3). A femoral cone was inserted in 6 patients, a tibial cone was inserted in 5, a double cone in 6 (femoral and tibial), and a triple cone in 1 (1 femoral and 2 tibial). A constrained condylar implant (LCCK, Zimmer, Warsaw) was inserted in 6 patients and a rotating hinge knee implants (RHK, Zimmer, Warsaw, IN) in 12 pateints. All patients were prospectively followed for clinical and radiographic evaluation preoperatively and postoperatively at 1, 3, 6 months, one year and yearly thereafter. Results. Knee Society knee scores improved from a mean of 31.3 points before surgery to 76.7 points at latest followup (p < 0.001). Knee Society function scores improved from a mean of 21.7 points before surgery to 65.4 points at latest followup (p < 0.001). The average flexion contracture was 6° and the average flection was 88°. At the time of the latest follow-up the average flexion contraction was 3° and the average flexion was 105°. No radiolucent lines were seen between the cones and the adjacent tibial and femoral bone at the latest follow-up. There was no evidence of loosening or migration of any implant at the time of the final follow-up. There have been two reoperations for recurrent infection (11%). Conclusions. Our experience demonstrates excellent clinical and radiographic mid-term outcomes and confirms that metaphyseal fixation with porous tantalum cones can be achieved. Long-term follow up and comparative studies are necessary

Bone grafts are a useful option to treat large posteromedial defects in tibia which are usually seen in medial condyle of the tibia in severe varus knees and lateral condyle in valgus knees. Contained defects can be treated using cancellous bone chips/graft. Uncontained peripheral defects may be treated using cement with or without screw augmentation for small defects. Large defects > 25 % of tibial plateau and > 5 mm deep may need structural bone graft or impaction bone grafting or metal wedges. The use of bone grafts is a viable alternative for the treatment of massive bone loss. For stable fixation of the components, we performed osseous reconstruction of tibial condyle using autologous structural bone grafts /impaction bone grafting. We used structural bone graft for 62 tibial defects in severe varus knees in 675 primary TKR. Grafts originating from the femoral condyles were fixed with screws. Morselised autograft supported by mesh, fixed with screws, were used in 8 patients. Bilateral bone grafting was done in 28 patients. Goal was to obtain firm seating of the tibial tray on a rim of viable bone along with rigid press fixation of the medullary stem. We observed an average 70-point postoperative increase in knee function according to HSS score. Graft incorporation was seen in all patients at average seven year follow-up. Autologous bone grafts can be successfully used for reconstruction of large osseous defects. It is available then and there, is biological and cost effective

Purpose of the study. To use a simple way of manipulating Taylor Spatial Frame to achieve soft tissue closure by acute intentional deformation and then gradually achieving anatomical alignment of the fracture without complex deformity and frame parameters. Methods and end results. 10 consecutive cases of Gustillo III B open fractures of tibia and of soft tissue defect due to infected implant were treated with a new technique of acute intentional deformation using Taylor Spatial frame to successfully close the soft tissue defect without plastic surgery. We describe a new simple technique of achieving anatomical alignment of the fracture after creating complex deformity to close the soft tissue defect. We achieved complete full thickness cover of the exposed bone in all cases without plastic surgery and restored the bone to anatomical alignment. Only one patient needed additional Taylor Spatial Frame total residual prescription to correct minor residual deformity. Conclusion. We describe a simple way of using Taylor Spatial Frame (TSF) for acute deformation of Gustilo IIIB tibial fractures and other tibial defects in order to close soft tissue defects and gradual correction to the anatomical alignment. We have used the Direct Scheduler Utility module of the web-based software for Taylor Spatial Frames (TSF) to successfully restore the anatomical alignment

Purpose of the study. To use a simple way of manipulating Taylor Spatial Frame to achieve soft tissue closure by acute intentional deformation and then gradually achieving anatomical alignment of the fracture without complex deformity and frame parameters. Methods and end results. 10 consecutive cases of Gustillo III B open fractures of tibia and of soft tissue defect due to infected implant were treated with a new technique of acute intentional deformation using Taylor Spatial frame to successfully close the soft tissue defect without plastic surgery. We describe a new simple technique of achieving anatomical alignment of the fracture after creating complex deformity to close the soft tissue defect. We achieved complete full thickness cover of the exposed bone in all cases without plastic surgery and restored the bone to anatomical alignment. Only one patient needed additional Taylor Spatial Frame total residual prescription to correct minor residual deformity. Conclusion. We describe a simple way of using Taylor Spatial Frame (TSF) for acute deformation of Gustillo IIIB tibial fractures and other tibial defects in order to close soft tissue defects and gradual correction to the anatomical alignment. We have used the Direct Scheduler Utility module of the web-based software for Taylor Spatial Frames (TSF) to successfully restore the anatomical alignment

The biological properties of morselised bone allograft treated with either a supercritical fluid process or low-dose (15 kGy) gamma irradiation were compared using radiological, histological and immunohistological techniques. The aims were to investigate any differences in the biological properties of supercritical fluid treated allograft and low-dose gamma irradiated allograft in-vivo. Rabbit allograft were cleaned of all soft tissue, cartilage and processed into ‘corticancellous crunch’ using a Noviomagus Bone Mill. Pooled samples were either gamma irradiated (15 kGy) or treated by NovaSterilis using super critical carbon dioxide. A well-reported tibial defect model in ten rabbits was used to examine the in vivo response of the different treatments at two and four weeks following surgery (n=5 per time point). Radiographic (x-ray, CT and micro CT), histology and immunohistochemistry was used to assess the in vivo response. Radiographic results revealed an initial response to the gamma-irradiated samples compared to SCF. Histology confirmed this reaction to be inflammatory in nature at two weeks that continued at four weeks for the gamma irradiated samples. In contrast, the SCF treated sample demonstrated new bone formation while the inflammatory reaction was muted compared to the gamma irradiated samples. Four week x-rays and histology confirmed new bone formation in both groups while the lack of significant inflammatory response in the SCF group was noted. Allograft sterilisation techniques do not result in the same initial response when evaluated in vivo. Removal of lipids and cellular debris following SCF treatment may influence the in vivo response. While both techniques can provide a sterile product, the in vivo response requires further investigation

Introduction. Coronal plane deformity can pose difficulties with balancing in Total Ankle Replacement (TAR). Current reports outline improved outcomes in the presence of varus deformity. Soft tissue balancing techniques are well described, but are limited by no link to eitiology and pathoanatomy of the deformity. Method. A prospective review of all the TAR by the senior author was performed to identify cases of pre-operative varus greater than 10°. A chart review was performed to identify aetiology, intraoperative findings, and operative techniques to achieve a balanced TAR. X-rays were examined to measure deformity and amount of correction. Volumetric rendering and segmentalisation was performed on pre- and post-CTs to identify anatomical defects, osteophyte formation, rotational and translational changes of the hindfoot joints. Results. Between January 2002 and January 2009 there were thirty-five cases from two hundred and thirty cases with varus deformity greater than 10°, with an average 17° varus angle (range 10° to 30°). Multiple sprains and instability over several years was seen in 62% of patients. Clinically, increasing varus was associated with cavovarus foot position. Incongruent deformities had intact tibial plafond. Congruent deformities had tibial defects in the anteromedial tibial plafond and associated anterolateral tibial ostephyte. Increasing deformity often had lateral fibula osteophytes and ossicles between fibula osteophyte and anterolateral talar body. In more severe cases, 3D analysis showed the talus was anteriorly displaced and internally rotated. Post operative alignment improved from 17° to 1.5°. Conclusion. Understanding the pathoanatomy of the arthritic ankle with coronal plane deformity can help plan the surgical techniques required to correct this often challenging surgical reconstruction

Treatment of large segmental defects in the extremities is challenging. A segmental tibial defect model in a large animal can provide a basis through which in vivo testing of materials and techniques for use in non-unions and severe trauma cases can be examined. This study reports such a model. Six aged ewes (> 5 years) were used following ethical approval. A 5cm piece of the mid diaphysis of the left tibia was removed including its associated periosteum. The tibia was stabilized with an 8mm stainless steel cross locked intramedullary nail and all tissues closed in their respective layers. Animals were euthanised at 12 weeks following surgery and evaluated using radiographic, micro-computed tomography (CT), soft tissue and hard tissue histology techniques. Three weeks post operatively one of the intramedullary nails failed through the first of the distal two cross locking screw holes, the sheep was euthanised and the tibia was harvested. Early signs of callus formation were evident at the osteotomy edges originating from the periosteal surface; the defect space was bridged by fibrous scar tissue. The remaining 5 sheep were taken out to the 12 week time point then all relevant tissues were harvested. Gross dissection revealed a lack of bony union in the defect site and no evidence of infection. X-rays and CT showed a lack of hard tissue callus bridging in the defect region at 12 weeks. Histological sections of the bridging tissues revealed, callus originating from both the periosteal and endosteal surfaces, with fibrous tissue completing the bridging in all instances. One case had cartilaginous tissue developing; however this was incomplete at 12 weeks. As none of the 12 week time point sheep achieved clinical union; this model may be effective as a basis for the investigation of healing adjuncts to be used in non-union cases, where severe traumatic injury has lead to significant bone loss such as blast injuries or following large tumour removal