Knee joint distraction (KJD) is a joint-preserving treatment strategy for severe osteoarthritis (OA) that provides long-term clinical and structural improvement. Data from both human trials and animal models indicate clear cartilage regeneration from 6 months and onwards post-KJD. However, recent work showed that during distraction, the balance between catabolic and anabolic indicators is directed towards catabolism, as indicated by collagen type 2 markers, proteoglycan (PG) turnover and a catabolic transcription profile [unpublished data]. The focus of this study was to investigate the cartilage directly and 10 weeks after joint distraction in order to elucidate the shift from a catabolic to an anabolic cartilage state. Knee OA was induced bilaterally in 8 dogs according to the groove model. After 10 weeks of OA induction, all 8 animals received right knee joint distraction, employing the left knee as an OA control. After 8 weeks of distraction, 4 dogs were euthanized and after 10 weeks of follow-up the 4 other dogs. Macroscopic cartilage degeneration and synovial tissue inflammation was assessed using the OARSI canine scoring system. PG content was determined spectrometrically using Alcian Blue dye solution and the synthesis of newly formed PGs was determined using . 35. SO. 4. 2-. as a tracer, as was described before. Directly after KJD, macroscopic cartilage damage of the right tibial plateau was higher compared to the left OA control (OARSI score: 1.7±0.2 vs 0.6±0.3; p < 0.001). 10 weeks post-KJD this difference persisted (OARSI score: 1.4± 0.6 vs 0.6±0.3; p = 0.05). Directly after KJD, there was no difference in synovial inflammation between KJD and OA control (OARSI score: 1.4±0.5). At 10 weeks synovial inflammation increased significantly in the distracted knee (OARSI score: 2.1±0.3 vs 1.4±0.5; p < 0.05). Biochemical analysis of the tibia cartilage directly after KJD revealed a lower PG content (20.1±10.3 mg/g vs 23.7±11.7 mg/g). At 10 weeks post-KJD this difference in PG content was less (24.8±6.8 mg/g vs 25.4±7.8 mg/g). The PG synthesis rate directly after KJD appeared significantly lower vs. OA (1.4±0.6 nmol/h.g vs 5.9±4.4 nmol/h.g; p < 0.001)). However, 10 weeks post-KJD this difference was not detected (3.7±1.2 nmol/h.g vs 2.9±0.8 nmol/h.g), and the synthesis rate in the distracted knee was increased compared to directly after distraction (p < 0.01). Further in-depth investigation of the material is ongoing; these first results suggest that the shift from a catabolic to an anabolic state occurs within the first weeks after joint distraction, mostly reflected in the biochemical changes. As such, the post-distraction period seems to be essential in identifying key-players that support intrinsic cartilage repair

Bilateral mandibular lengthening is widely accepted during mandibular distraction osteogenesis. However, distraction osteogenesis are sometimes associated with clinical complications such as open bite deformity, lateral displacement of temporo-mandibular joint, premature consolidation and pin loosening. Although distraction osteogenesis aims to develop pure tensile strain on the regenerate tissue however, in real life situation due to differences in device orientation, materials and misalignment it is often subjected to complex stress and strain regimes. The objective of this study was to characterise the mechanical environment (stress and strain) in the Finite Element Models (FEM) of regenerate tissue during two different device orientations:. (a) device placed parallel to the mandibular body. (b) device placed parallel to the axis of distraction. Furthermore, the influence of misalignment from above two idealised orientations was also investigated. The distraction protocol in this study was similar to previous study of Loboa et al (2005). FE models were developed at four stages: end of latency, distraction day two, distraction day five and distraction day eight. At each time period a distraction of 1mm was applied to the model as it is most widely used distraction rate. In these models two primary distraction vectors were simulated; first when the device is parallel to the body of the mandible and second when the device is parallel to the axis of distraction. Results indicate that when the device is placed parallel to the mandible the effect of distraction vector variation due to misalignment in transverse plane (±150 at an interval of 50 ; + indicate lateral and indicates medial) is symmetric and variation in the stress and strain regimes on regenerative tissue are less than 3%. However, when the device is placed parallel to axis of distraction the corresponding change is asymmetric and almost double in magnitude. The greatest differences were seen when misalignment is towards lateral side (+150). Similarly in the sagittal plane variations up to 17% were developed due to 0- 400 change in the distraction vector orientation. Thus the orientation of device which determines the distraction vector plays an important role in determining the mechanical environment around regenerative tissue. The results suggest that implications of misalignment of the device and its sensitivity from the ideal situation should be well understood during clinical planning

Introduction. Intra articular distal tibia fractures can lead to post-traumatic osteoarthritis. Joint distraction has shown promise in elective cases. However, its application in acute fractures remains unexplored. This pilot study aims to fill this knowledge gap by investigating the benefits of joint distraction in acute fractures. Materials & Methods. We undertook a restrospective cohort study comprising patients with intra-articular distal tibia and pilon fractures treated with a circular ring fixator (CRF) at a single center. Prospective data collection included radiological assessments, Patient-Reported Outcome Measures (PROM), necessity for additional procedures, and Kellgren and Lawrence grade (KL) for osteoarthritis (OA). 137 patients were included in the study, 30 in the distraction group and 107 in the non-distraction group. There was no significant difference between the groups. Results. Mean follow-up was 3.73 years. There was no significant difference between the groups in overall complications or need for further procedures. There was no significant difference in progression of KL between the groups (1.81 vs 2.0, p=0.38) mean follow up 1.90 years. PROM data was available for 44 patients (6 distraction, 38 non-distraction) with a mean follow-up of 1.71 years. There was no significant difference in EQ5D (p=0.32) and C Olerud-H Molander scores (p=0.17). Conclusions. This pilot study suggests that joint distraction is safe in the acute setting. However, the study's impact is constrained by a relatively small patient cohort and a short-term follow-up period. Future investigations should prioritise longer-term follow-ups and involve a larger patient population to more comprehensively evaluate the potential benefits of joint distraction in acute fractures

Introduction. Despite all modern advances the indications and possibilities of treatment in Legg-Calvé-Perthes Disease (LCPD) are still controversial. In the past 15 years we started using arthrodiastasis of the hip creating negative pressure over the avascular femoral head in some selected cases of LCPD in the active phasis of the disease. Now we present our experience with distraction in LCPD using the original Ilizarov circular frame for the hip. Materials and Methods. From 2015 to 2021, eight patients with LCPD were submoitted to hip distraction; all male ranging from six to 12 years (avg 8.2 years). All patients with bad prognosis, in Catterall Groups III and IV. All patients in the active phasis of the disease. Our follow-up is ranging from two to six years, with an average of 3.4 years. Results. All the preliminary results are good with recovering of range of motion of the affected hip joint in allpatients. After the first month under distraction is possible to observe new bone formation specially in the lateral pillar of the femoral head. Complications were not observed in this group of patients. Conclusions. The main point of this prospective study is to find that is possible to achieve cartilaginous growth on the femoral head stimulated by the traction offered by the external fixator, in a very short period of time. Distraction may be one method for a good treatment in patients aged six years or older with Legg-Calvé-Perthes disease in the active phase of the disease

Introduction. Fully implantable distraction nails are frequently used for lengthening of the lower leg. What are the indications for humerus lengthening and which results can be expected?. Materials and Methods. The humerus as the best healing bone in the human body is suitable for lengthening with a nail as well but the indications are rare in comparison with the lower legs. Especially when driving a car or when working on a tablet length discrepancy of the arms of more than 4–5cm may cause severe hardening of the cervical muscles and induce chronical pain in the upper spine. Results. A distraction nail (FITBONE) was used in 5 cases for humerus lengthening. The nail was inserted in all cases from proximal. The mean age of the patients was 34 years. The mean lengthening amount was 58mm (55–100). In one case the system was exchanged to reach the desired length. There was no infection, no radial nerve irritation and no chronical shoulder pain. The system was removed in 4 cases in an average of 15 months the other nail will be removed soon as well. Conclusions. The preliminary results of our 5 cases demonstrate, that the FITBONE device is advantageous for lengthening the humerus, if the initial length is sufficient for implantation. In comparison with the use of external fixators the functional outcome, the comfort of treatment and the cosmetic result is amazing

Management of ankle arthritis in young patients is challenging. Although ankle arthrodesis gives consistent pain relief, it leads to loss of function and adjacent joint arthritis. Ankle joint distraction (AJD) has been shown to give good outcomes in adults with osteoarthritis or post-traumatic arthritis. The efficacy in children or young adults and those with juvenile idiopathic arthritis is less well evidenced. Clinical notes and radiographs of all patients (n=6) managed with AJD in one tertiary referral centre were retrospectively reviewed. Radiographs were taken pre-surgery, intra-operatively, 1 month following frame removal and at the last follow up, tibiotalar joint space was assessed using ImageJ software. Measurements were taken at the medial, middle and lateral talar dome using frame components as reference. Radiographic data for patients with a good clinical outcome was compared with those who did not. At time of surgery mean age was 16.1 years (12 – 25 years). Mean follow up was 3.4 years (1.5 – 5.9 years). Indications were juvenile idiopathic arthritis (4) post-traumatic (1) and post-infective arthritis (1). Three patients at last follow up had a good clinical outcome. Two patients required revision to arthrodesis (1.3 and 2.4 years following distraction). One patient had spontaneous fusion. One patient required oral antibiotics for pin site infection. Inter-observer reliability was 95%. Mean joint space was 1.17mm (SD = 0.87mm) pre-operatively which increased to 6.72mm (SD = 2.23mm) at the time of distraction and 2.09mm (SD = 1.14mm) at the time of removal. At one-year follow up, mean joint space was 1.96mm (SD = 1.97mm). Outcomes following AJD in this population are variable although significant benefits were demonstrated for 50% of the patients in this series. Radiographic joint space preoperatively did not appear to be associated with need for arthrodesis. Further research in larger groups of young patients is required

Knee joint distraction (KJD) has been associated with clinical and structural improvement and synovial fluid (SF) marker changes. However, structural changes have not yet been shown satisfactorily in regular care, since radiographic acquisition was not fully standardized. AI-based modules have shown great potential to reduce reading time, increase inter-reader agreement and therefore function as a tool for treatment outcome assessment. The objective was to analyse structural changes after KJD in patients using this AI-based measurement method, and relate these changes to clinical outcome and SF markers. 20 knee OA patients (<65 years old) were included in this study. KJD treatment was performed using an external fixation device, providing 5 mm distraction for 6 weeks. SF was aspirated before, during and immediately after treatment. Weight-bearing antero-posterior knee radiographs and WOMAC questionnaires were collected before and ~one year after treatment. Radiographs were analysed with the Knee Osteoarthritis Labelling Assistant (KOALA, IB Lab GmbH, Vienna, Austria), and 10 pre-defined biomarker levels in SF were measured by immunoassay. Radiographic one-year changes were analysed and linear regression was used to calculate associations between changes in standardized joint space width (JSW) and WOMAC, and changes in JSW and SF markers. After treatment, radiographs showed an improvement in Kellgren-Lawrence grade in 7 of 16 patients that could be evaluated; 3 showed a worsening. Joint space narrowing scores and continuous JSW measures improved especially medially. A greater improvement in JSW was significantly associated with a greater improvement in WOMAC pain (β=0.64;p=0.020). A greater increase in MCP1 (β=0.67;p=0.033) and lower increase in TGFβ1 (β=-0.787;p=0.007) were associated with JSW improvement. Despite the small number of patients, also in regular care KJD treatment shows joint repair as measured automatically on radiographs, significantly associated with certain SF marker change and even with clinical outcome

Critical size bone defects are frequently caused by accidental trauma, oncologic surgery, and infection. Distraction osteogenesis (DO) is a useful technique to promote the repair of critical size bone defects. However, DO is usually a lengthy treatment, therefore accompanied with increased risks of complications such as infections and delayed union. Herein, we developed an innovative intramedullary biodegradable magnesium (Mg) nail to accelerate bone regeneration in critical size bone defect repair during DO. We observed that Mg nail induced almost 4-fold increase of new bone formation and over 5-fold of new vessel formation at 2 weeks after distraction. Mg nail upregulated the expression of calcitonin gene-related peptide (CGRP) in the new bone as compared with the DO alone group. We further revealed that blockade of the sensory nerve by overdose capsaicin blunted Mg nail enhanced critical size bone defect repair during the DO process. Moreover, inhibitors/antagonist of CGRP receptor, FAK, and VEGF receptor blocked the Mg nail stimulated vessel and bone formation. In summary, we revealed, for the first time, a CGRP-FAK-VEGF signaling axis linking sensory nerve and endothelial cells, which may be the main mechanism underlying Mg-enhanced critical size bone defect repair when combined with DO, suggesting a great potential of Mg implants in reducing DO treatment time for clinical applications

Chronic pelvic discontinuity (CPD) during revision hip arthroplasty is a challenging entity to address. The aim of this study was to evaluate the clinical and radiologic outcomes, and complications of the “acetabular distraction technique” for the management of CPD during revision hip arthroplasty. Patients with CPD, who underwent acetabular revision between 2014 and 2022 at two tertiary care centres, using an identical distraction technique, were evaluated. Demographic parameters, pre-operative acetabular bone loss, duration of follow-up, clinical and radiologic outcomes, and survivorship were evaluated. In all, 46 patients with a mean follow-up of 34.4 (SD=19.6, range: 24–120) months were available for evaluation. There were 25 (54.3%) male, and 21 (45.7%) female patients, with a mean age of 58.1 (SD=10.5, range: 40–81) years at the time of revision surgery. Based on the Paprosky classification of acetabular bone loss, 19 (41.3%), 12 (26.1%), and 15 (32.6%) patients had type 3b, 3a, and 2c defects. All patients were managed using the Trabecular Metal™ Acetabular Revision System; 16 patients required additional Trabecular Metal™ augments. The mean HHS improved from 50.1 (SD=7.6, range: 34.3 – 59.8) pre-operatively, to 86.6 (SD=4.2, range: 74.8 -91.8) at the last follow-up. Two patients (4.3 %) developed partial sciatic nerve palsy, two (4.3%) had posterior dislocation, and one (2.2%) required re-revision for aseptic loosening. Radiologically, 36 (78.3%) patients showed healing of the pelvic discontinuity. The Kaplan-Meier construct survivorship was 97.78% when using re-revision for aseptic acetabular loosening as an endpoint. The acetabular distraction technique has good clinical and radiologic outcomes in the management of CPD during revision hip arthroplasty

Introduction. Pelvic discontinuity is a challenging complication. One treatment option that has garnered enthusiasm is acetabular distraction. This method obtains stability via distraction of the discontinuity and placement of an oversized socket (± augments) and elastic recoil of the pelvis. The aims of this study were to report implant survivorship, radiographic results, clinical outcomes, and complications of acetabular distraction for pelvic discontinuity in the largest series to date. Methods. We retrospectively identified all revision THAs with a Paprosky 3B defect and pelvic discontinuity between 2005 and 2017. Of the 162 patients, 32 were treated with distraction. The mean distraction achieved was 5mm (range, 3–8mm). In addition to distraction with a hemispherical cup, augments were utilized in 3 and cages in 19. The mean age at revision was 68 years with 75% female. Mean follow-up was 3 years. Results. The 2-year survivorships free from revision for aseptic loosening, revision, and reoperation were 95%, 75%, and 69%, respectively. There were 3 revisions including one for instability, one for infection, and one for aseptic loosening. At last follow-up, 16 patients had radiographic evidence of cup osteointegration to ilium and ischium, 13 to ilium only, and 3 without evidence of osteointegration (two distracted 3mm and one distracted 6mm). 19 discontinuity lines persisted while 13 had radiographically healed. Only those with osteointegration to both ilium and ischium had evidence of bone graft consolidation and discontinuity line healing. Mean HHS improved from 43 preoperatively to 77 postoperatively (p<0.0001). The most common complication was a postoperative sciatic nerve plasy in 4 patients (13%) of which 3 partially recovered. Conclusion. Pelvic discontinuities treated with acetabular distraction had a 2-year survivorship free from aseptic looseing of 95%. While nearly 2/3. rd. of discontinuity lines persisted, 91% of patients had radiographic evidence of osteointegration of the acetabular component. However, 13% of patients had a sciatic nerve palsy. For any tables or figures, please contact the authors directly

Introduction. Fully implantable systems are used commonly only after maturity. What are indications to use fully implantable systems at the femur even in children?. Materials and Methods. Implantable lengthening nails (FITBONE) were used retrograde at the femur in minimal invasive technique to correct a limb length discrepancy of >6 cm. In 5 cases a relevant deformity was corrected in the same surgery. In all cases a final step of lengthening was planned at the femur and at the tibia with fully implantable devices at maturity. Results. 18 patients with the medium age of 10,3 years (8–14) were treated. In 17 cases the goal of lengthening was achieved without any complication. In one case of proximal femoral deficiency lengthening had to be stopped because of increasing tendency of knee joint luxation. Bone formation occurred circular around the nail in all cases. Full load bearing was possible in the average after 2,2 days/mm. No technical problems occur. In one case induced deformity in the lateral plane was observed which was corrected at the final step. At the end of treatment functional and cosmetical result was perfect in all cases. Conclusions. Fully implantable motorized distraction nails are a favorable option for lengthening and deformity correction of the femur even for children older than 10 years to correct limb length discrepancy of more than 6 cm. The treatment has a low pain level, is comfortable and nearly no scars are visible

Purposes:. See if permanent damage of the growth plate after physeal distraction is the rule and. Identify factors with influence on the viability of the physis after physeal distraction. Introduction: Surgeons have always been concerned about the fate of the growth plate after physeal distraction and for that reason this technique has usually been considered only in patients nearing maturity. Previous experimental work has shown that the velocity of distraction has an influence on the viability of the growth plate at follow-up (recommended rate: 0.5 mm/day). Clinically, it has also been our observation that the condition of the physis prior to distraction is another important factor related to physeal function in the long term. Patients and methods: Since 1987 we have used low velocity physeal distraction in 43 bone segments of which 37 cases have been followed-up at least for 24 months and this has been the group included in this study. The indications were lengthening (14), angular deformity correction (19) and resection of benign bone tumours (4). Most patients (24) were older than 10 y.o. and 22 of them were followed-up until maturity. We have retrospectively reviewed these patients looking at the radiological morphology and function of the distracted growth plate at follow-up. Results: Out of the 24 children older than 10 y.o., twenty showed a premature complete physeal closure. We looked with interest at the 13 cases younger than 10 y.o. since the repercussions of iatrogenic physeal damage would obviously be bigger in this age group. Five out of the 13 showed premature closure and in the remnant eight an open growth plate was observed at follow-up. All patients with open and/or functioning physes after distraction had no local injuries in the growth plate prior to distraction (4 congenital short femora and 4 normal physes). On the contrary, four out of the five cases with prematurely closed physes, had a local physeal damage prior to distraction (3 bony bridges and one non-union), and the remnant was a congenitally short femur. Growth after distraction was difficult to assess in the congenitally short femora but it has been very satisfactory in the 4 cases of previously normal physes (2 benign tumours and 2 femoral shortenings due to hip disorders). In three cases of congenital short femur in pre-teenagers we were able to repeat distraction twice through the same physis, since it had remained open after the first distraction. Conclusions: Physeal premature closure often follows physeal distraction, but not always. The condition of the physis prior to lengthening is an important factor with influence on its viability after distraction

Purpose. Despite total knee arthroplasty (TKA) is a successful surgical procedure with end-stage knee osteoarthritis, approximately 20% of the patients who underwent primary TKA were still dissatisfied with the outcome. Thereby, numerous literatures have confirmed the relationship between soft tissue balancing and clinical result to improve this pressing issue. Recently, there has been an increased research interest in patient-reported outcome measures (PROMs) after TKA. However, there is little agreement on the association between soft tissue balancing and PROMs. Therefore, the purpose of this study was to determine whether intraoperative soft tissue balancing affected PROMs after primary TKA. We hypothesized that soft tissue balancing would be a predictive factor for postoperative PROMs at one-year post-surgery. Patients and Methods. The study included 20 knees treated for a varus osteoarthritic deformity using a cruciate-retaining TKA (Scorpio NRG) with a polyethylene insert thickness of 8 mm retrospectively. Following the osteotomy using the measured resection technique, the extension gap was measured with a femoral trial by using an electric tensor. This instrument could estimate the soft tissue balance applying continuous distraction force simultaneously from 0 to 40 lbf with an accuracy of the 0.1 lbf. We evaluated the association between a distraction force required for an extension gap of 8 mm, and the following potentially affected factors at one year postoperatively: knee flexion angle using a protractor with one degree increments; radiographic parameters of component alignment, namely the femoral and tibial component medial angle; and the Japanese Knee Osteoarthritis Measure (JKOM). This is a disease-specific and self-administered questionnaire, reflecting the specificity of the Japanese cultural lifestyle, consisting of 25 items scored from 0 to 100 points, with 100 points being worst. Outcomes. The median knee flexion angle was 130 degrees with the femoral and tibial component of 97 and 89 degrees, respectively. For an extension gap of 8 mm, a verified value of a distraction force did not demonstrate a correlation with, knee flexion angle (p = 0.29) or with the femoral (p = 0.20), and tibial component position (p = 0.09). The median JKOM totaled 20 points across 4 domains: pain and stiffness, condition in daily life, general activities, and health conditions with 5, 8, 2.5, and 2 points respectively. There was significant correlation between a required force and the JKOM (r. s. = 0.53, p = 0.02), and notably the domain of health conditions exhibited the highest coefficient of determination (r. s. = 0.54, p = 0.01). Discussion. This study highlights that distraction force for an extension gap of 8 mm is an independent variable in component position or knee flexion angle. We found that soft tissue balancing could influence short term postoperative PROMs. Our results will contribute to a better understanding of outcomes after TKA. This is a particularly critical issue as feasible strategies to avoid a persistent joint stiffness would improve long-term function after TKA and patient satisfaction

Osteoarthritis (OA) is a disease of the joints stemming from a variety of factors, including joint injuries and abnormally high mechanical loading. Although the traditional treatment alternatives for end-stage OA are arthroplasty in the case of the hip and knee, and arthroplasty or arthrodesis in the case of the ankle, these options are not ideal for younger, more active patients. For these patients, joint prostheses would be expected to fail relatively quickly, and ankle fusion is not amenable to maintaining their active lifestyles. In these cases, joint distraction has attracted investigative attention as a conservative OA treatment for younger patients. 9-14. . Based on the principle that decreasing the mechanical load on cartilage stimulates its regeneration. 15. , distraction treatment calls for reduced loading of the joint during a period of typically 3 months, during which time the load customarily passing through the joint is taken up by an external fixator spanning the joint . By mounting the fixator components to the bone on each side of the joint, and then lengthening the rods connecting the proximal and distal portions of the fixator, the joint is distracted. Assuming the fixation is appropriately stiff, any load passes through the fixator instead of the joint, and the two articular surfaces will not be allowed to contact each other under physiologic loading. The exact mechanisms leading to cartilage regeneration during distraction are not yet understood. A possible negative consequence of joint fixation is cartilage degeneration due to immobilization during the treatment. It has been shown by Haapala et al. and others that long-term immobilization can be detrimental to articular cartilage. 16-18. . Conversely, joint motion during fixation (even passive motion) is thought to stimulate or encourage cartilage regeneration. 19-22. Toward this end, considerable effort has been invested in the application of hinges to external fixation for joints Joint motion has also been suggested as a potentially beneficial factor in distraction treatment, as well. 10. This is borne out by data from an RCT comparing the use of a rigid vs motion external fixator. Change in joint biology due to resorption of cysts may be responsible for reversal of symptoms

Acetabular distraction for the treatment of chronic pelvic discontinuity was first described by Sporer and Paprosky. The authors advocate the posterolateral approach for exposure of the posterior ilium and posterior column, The patient is secured in the lateral decubitus position. Following a systematic approach to surgical exposure, acetabular component removal should be performed with “cup out” osteotomes resulting in minimal iatrogenic bone loss. Following component removal and confirmation of a chronic discontinuity determine the integrity of the remaining AS and PI columns. If porous metal augments are needed for primary stabilization, the augments are placed prior to cup insertion for reconstruction of the AS and/or PI column. Next, Kirschner (K) wires (size 2.4) are placed in the remaining AS and PI bone so that the distractor can be secured in an extra-acetabular position. The distractor is placed over the K-wires allowing for lateral or peripheral acetabular distraction and resultant medial or central compression at the discontinuity. With the distractor in an extra-acetabular position, hemispherical reamers are used until an interference fit is achieved between the native or augmented AS and PI columns. The acetabulum should be reamed on reverse to avoid excessive removal of host bone. When the proper acetabular component size has been reached, the reamer will disengage from the reamer handle and the reamer can be used as a surrogate acetabular shell; when the acetabulum is maximally distracted, the entire construct will move as a unit. Crushed cancellous allograft is used to bone graft the discontinuity and reamed on reverse. A revision tantalum cup is inserted with continual distraction using the distractor. Cement is applied to the augment surface prior to cup insertion in order to utilise the construct. Following cup insertion, the distractor and K-wires are removed. Adjuvant screw fixation is performed, with a minimum of 4 screws, and placing at least one of the screws inferiorly for fixation in the superior public ramus or ischium to prevent abduction failure of the construct. In the setting of severely osteoporotic bone and inadequate screw fixation, an augment placed posterosuperiorly can be used for supplemental fixation. This augment is also unitised to the cup with cement at the same time as the liner is cemented into the cup. Bone wax is placed over the exposed tantalum surface of the posterosuperior augment to minimise soft-tissue ingrowth into the augment

Purpose. To assess the efficacy of the treatment of the aseptic hypertrophic nonunion of the tibia and the secondary deformities by distraction-osteogenesis. Material Methods: Between 1998 and 2006, 28 patients with a hyperthrophic tibia nonunion were treated by distraction or compression-distraction depending on the mobility of the nonunion. The mean age of the patients was 37.5 years (range 24 to 68) and the average number of previous surgeries on the affected limb was 2 (from 1 to 4). No active bone infection or history of infection was recorded in this series. Closed distraction was applied in 11 patients, closed distraction – compression in 8 and osteoclasis following by distraction in 9 patients. In all cases an external fixation device (19 circular, 11 monolateral external frames) modified to meet the nonunion requirements was used. Results: Distraction or distraction-compression resulted in solid union in all patients (mean time to union 8.4 months, mean follow up 5 years). The external fixator remained in place for an average of 8.2 months (range 7 to 11.5 months). Mean leg length discrepancy 2.5 cm and mean angular deformity 12° were also corrected on the same procedure. Conclusions: Treatment of the tibia nonunion by callus distraction or distraction – compression leads to successfully results. The procedure and the frame have to be individualized according to the nonunion pathology and the secondary tibia deformities

Linear spinal cord distraction, in animal models, leads to elevated intra-compartmental spinal cord pressure. We developed an in vitro model of distraction, with increasing tensile force, to demonstrate the relationship between the degree of spinal curvature and the proportional elevation of intra-compartmental pressure. Six Porcine spinal sections, two cervical, two thoracic, and two lumbar were harvested from 30kg pigs. These cord sections were individually stretched in a saline solution with increasing tensile force applied. Cord interstitial pressure (CIP) was monitored with an arterial line pressure monitor. The sections were each tested six times fresh, and then thawed and tested an additional six times. An additional ten freshly thawed cords were tested in linear distraction and over forty-five degree and ninety degree curved surfaces with CIP monitoring. Increased tension, by adding increasing weights of distraction, lead to a proportionally elevated CIP in the linear model (R=0.986). We achieved a 99% confidence interval via paired T testing to demonstrate that there was no significant difference between fresh specimens and recently thawed cords. As the degree of spinal curvature increased from a linear model, to a forty-five and ninety degree (cobb) curve, there were significant increases in CIP at the same distraction force. The more significant the curve, the greater the CIP for each increment in distraction force; ninety degree curves produced a 2.3x higher pressure than linear distraction. High cord interstitial pressure (CIP) can be achieved through spinal cord distraction (> 140mm Hg). This CIP is no only directly proportional to tension, but also proportionally magnified by the degree of spinal curvature. It is not affected by freezing/thawing. This may suggest that spinal cord compartment syndrome is a potential mechanism for spinal cord distraction injury, and these distraction pressures are potentially magnified in the setting of scoliosis

Conservative management remains the gold standard for many fractures of the humeral diaphysis with union rates of over 90% often quoted. Success with closed management however is not universal. Phase 1. A retrospective review of all conservatively managed fractures between 2001 and 2005 was undertaken to investigate a suspected high non-union rate and identify possible causes. The overall non-union rate was 39.2% (11 of 28 cases). There was no difference in axial distraction at presentation, however following application of cast there was significantly more distraction in the non-union group (1.2 v 5.09mm, p<0.01). Changes to practise. All humeral fractures were admitted, lightweight U-slabs were applied by a technician, distraction was avoided, patients abstained from NSAIDS, consultant reviewed radiographs before discharge and patients were converted early to functional brace. Phase 2. Prospective collection of data over the following two year period showed a decrease in the amount of distraction when first placed in cast (2.73 v 0.74, p<0.05), a reduction in NSAID use (89% v 38%, p<0.01) and earlier conversion to brace (37 v 20 days p<0.01). These changes to practise led to a dramatic reduction in non-union rate from 39.2% to 4.9% (p<0.01). Conclusion. Over-distraction at first application of cast is a causal factor in the development of non-union. Lightweight cast, avoidance of distraction, abstinence from NSAIDS and early conversion to functional brace is recommended. The initial surgical management of the patient who displays evidence of distraction will prevent evolution of non-union with conservative management. This will avoid lengthy delays in the treatment of the non-union and also help to prevent secondary stiffness in adjacent joints and disuse osteopenia

Stabilisation of a pelvic discontinuity with a posterior column plate with or without an associated acetabular cage sometimes results in persistent micromotion across the discontinuity with late fatigue failure and component loosening. Acetabular distraction offers an alternative technique for reconstruction in cases of severe bone loss with an associated pelvic discontinuity. We describe the technique of acetabular distraction with porous tantalum components and evaluate its survival, function and complication rate in patients undergoing revision surgery for chronic pelvic discontinuity. Between 2002 and 2006, we treated 28 patients with a chronic pelvic discontinuity acetabular reconstruction using acetabular distraction. A porous tantalum elliptical acetabular component was used alone or with an associated modular porous tantalum augment in all patients. Three patients died and five patients were lost to follow-up before two years. The remaining twenty patients were followed semiannually for a minimum of two years (average, 4.5 years; range, 2–7 years) with clinical pain and walking scores as well as radiographic evaluation for loosening, migration or failure. In the remaining twenty patients available for follow-up, one patient did require re-revision for aseptic loosening. Fifteen patients remained radiographically stable at last follow-up. Four patients had early migration of their acetabular component but thereafter remained radiographically stable and clinically asymptomatic. The average improvement using the modified Merle d'Aubigne – Postel pain and ambulation score was 6.6 (range, 3.3–9.6). There were no postoperative dislocations; however, we did encounter one infection, one vascular injury and one bowel injury. In this series, the use of acetabular distraction with porous tantalum components provides a biologic alternative to cage constructs with more predictable clinical results (average follow-up 4.5 years) for reconstruction of severe acetabular defects with associated pelvic discontinuity

Stabilisation of a chronic pelvic discontinuity with a posterior column plate with or without an associated acetabular cage sometimes results in persistent micromotion across the discontinuity with late fatigue failure and component loosening. We believe that these chronic discontinuities are really chronic fracture non-unions incapable of healing. Acetabular distraction offers an alternative technique for reconstruction in cases of severe bone loss with an associated pelvic discontinuity. We describe the technique of acetabular distraction with porous tantalum components and evaluate its survival, function and complication rate in patients undergoing revision surgery for chronic pelvic discontinuity. Between 2002 and 2006, we treated 28 patients with a chronic pelvic discontinuity acetabular reconstruction using acetabular distraction. A porous tantalum elliptical acetabular component was used alone or with an associated modular porous tantalum augment in all patients. Three patients died and five patients were lost to follow up before two years. The remaining twenty patients were followed semiannually for a minimum of two years (average, 5.5 years; range, 2–9 years) with clinical pain and walking scores as well as radiographic evaluation for loosening, migration or failure. In the remaining twenty patients available for follow up, one patient did require re-revision for aseptic loosening. Fifteen patients remained radiographically stable at last follow up. Four patients had early migration of their acetabular component but thereafter remained radiographically stable and clinically asymptomatic. The average improvement using the modified Merle d'Aubigne – Postel pain and ambulation score was 6.6 (range, 3.3–9.6). There were no post-operative dislocations; however, we did encounter one infection, one vascular injury and one bowel injury. In this series, the use of acetabular distraction with porous tantalum components provides a biologic alternative to cage constructs with more predictable clinical results (average follow up 5.5 years) for reconstruction of severe acetabular defects with associated pelvic discontinuity