Aims

Excessive chondrocyte hypertrophy is a common feature in cartilage degeneration which is susceptible to joint overloading, but the relationship between mechanical overloading and chondrocyte hypertrophy still remains elusive. The aim of our study was to explore the mechanism of mechanical compression-induced chondrocyte hypertrophy.

Aims

Minimally manipulated cells, such as autologous bone marrow concentrates (BMC), have been investigated in orthopaedics as both a primary therapeutic and augmentation to existing restoration procedures. However, the efficacy of BMC in combination with tissue engineering is still unclear. In this study, we aimed to determine whether the addition of BMC to an osteochondral scaffold is safe and can improve the repair of large osteochondral defects when compared to the scaffold alone.

Certain technical advances, such as flexible intramedullary fixation and bioreabsorbable implants, have further increased enthusiasm for surgical management of pediatric fractures.» (Flynn et al.). In the Paediatric Surgery Department biodegradable pins of solid polydioxanone (PDS) in management of paediatric fractures have been used since April 1986. PDS pins are too soft for the osteosynthesis in fractures with fragments under high tensile pressures. However, we have successfully carried out a large number of internal fixations in children’s elbows. This is based on accurate distribution of PDS pins and careful positioning of periostal sutures and the adjacent disrupted muscles. Our technique, as presented at the 2nd European Congress of Paediatric Surgery in Madrid in 1997, is to fix temporarily the repositioned fractured fragment with Kirschner’s metal wire. Following osteosynthesis with PDS, the protruding K-wire is left in place for seven days until the limb is safely immobilized. A total of 96 patients were operated. The purpose of the study is to compare osteosynthesis with PDS pins (Group A) with that of metallic K-wire (Group B). Each group consisted of 48 children. General characteristics (age, sex, and fracture types) were statistically the same (P > 0.05). In Group A, with children between 2 and 13 years, or 9.3 on average, 21 children were with the lateral condyle fractures (43.75%), 25 children with medial epicondyle fractures (52.08%), and 2 children with medial condyle fractures (4.16%). In Group B, with children between 2 and 14 years, or 8.7 on average, 26 children were with lateral condyle fractures (54.16%), 19 children with medial epicondyle fractures (39.58%), and 3 with medial condyle fractures (6.25%). The study excludes Milch Type II fractures of medial and lateral condyles. The results have been examined in the follow-up period of one, three, and six months of two different methods according to Flynn’s criteria. After statistical evaluation the differences obtained had no statistical significance (P > 0.05). However, satisfaction score (0 – 10) is significantly higher in Group A than in Group B for both parents and evaluators (P < 0.05). Both treatments exhibit good results with the exception that the use of metal osteosynthetic material requires another operation. If metal wires are used and cut just underneath the skin, protruding with local inflammation may appear. Proper use of PDS pins requires no further operation. This is to the benefit for both the patient and rehabilitation staff

Chondral defects in the knee have cartilage biomechanical differences due to defect size and orientation. This study examines how the tibiofemoral contact pressure is affected by increasing full-thickness chondral defect size on the medial and lateral condyle at full extension. Isolated full-thickness, square chondral defects increasing from 0.09cm. 2. to 1.0cm. 2. were created sequentially on the medial and lateral femoral condyles of six human cadaveric knees with intact ligaments and menisci. Chondral defects were created 1.0cm from the femoral notch posteriorly. The knees were fixed to a uniaxial load frame and loaded from 0N to 600N at full extension. Contact pressures between the femoral and tibial condyles were measured using pressure mapping sensors. The peak contact pressure was defined as the highest value in the 2.54mm. 2. area around the defect. The location of the peak contact pressure was determined relative to the centre of the defect. Peak contact pressure was significantly different between (4.30MPa) 0.09cm. 2. and (6.91MPa) 1.0cm. 2. defects (p=0.04) on the medial condyle. On the lateral condyle, post-hoc analysis showed differences in contact pressures between (3.63MPa) 0.09cm. 2. and (5.81MPa) 1.0cm. 2. defect sizes (p=0.02). The location of the stress point shifted from being posteromedial (67% of knees) to anterolateral (83%) after reaching a 0.49cm. 2. defect size (p < 0.01) in the medial condyle. Conversely, the location of the peak contact pressure point moved from being anterolateral (50%) to a posterolateral (67%) location in defect sizes greater than 0.49cm. 2. (p < 0.01). Changes in contact area redistribution and cartilage stress from 0.49cm. 2. to 1.0cm. 2. impact adjacent cartilage integrity. The location of the maximum stress point also varied with larger defects. This study suggests that size cutoffs exist earlier in the natural history of chondral defects, as small as 0.49cm. 2. , than previously studied, suggesting a lower threshold for intervention

Aims and Objectives Lateral condyle fractures can be difficult diagnose and the treatment still remains controversial. It is well known that these fractures are prone to a number of complications, both early and late. The aim of this paper was to review the treatment practice of lateral condyle fractures presenting to a children’s hospital fracture unit over the past 5 years to identify any consistency in the management of these fractures. We also aimed to try and determine if a particular treatment method was more favourable than others in terms of complications and the need for further surgery with a view to developing a treatment protocol. Methods: We conducted a chart and x-ray review of all lateral condyle fractures treated operatively from December 1998 to August 2004. We recorded patients’ age, sex, side of injury and month of injury. The fractures were classified according to the Milch classification. We also measured the preoperative and postoperative fracture displacement. We recorded the nature of surgery (Examination Under Anaesthetic (EUA) and casting, Manipulation Under Anaesthetic (MUA) and wiring and Open Reduction and wiring). We documented whether the wires were percutaneous or buried. Length of time in cast and length of time to wire removal were also noted. Finally any complications and the need for further surgery were documented. Results: 90 patients were identified. 72% were male and 28% female, with an average age of 5.6. 28% of injuries were right sided, 72% were left sided. 21 (23%) patients were Milch Type 1 fractures and 66 (73%) were Type II fractures. Preoperative fracture classification was unavailable for 3 patients. In 78 patients we were able to determine the initial fracture displacement. 8 (9%) patients were displaced < 2 mm, 18 (20%) were displaced 2–4 mm and 52 (58%) were displaced > 4 mm. 7 patients (10%) had associated elbow dislocations – all of these were Milch type II fractures. 5 patients had EUA and casting, 19 had MUA and K wiring and 63 had open reduction and wiring. In the 19 patients who had MUA and K wiring, 13 were percutaneous and 6 were buried. In the open reduction and wiring group 59 patients had their wires buried and 6 were percutaneous. 1 patient did not have that information recorded. The average time in cast was 41 days. In those with buried wires average length of time to wire removal was 63 days. Average percutaneous wire removal was at 42 days. For the 5 patients undergoing EUA and casting residual displacement was < 2 mm in all. 2 of these patients (40%) had complications of lateral spur formation and delayed union. For the 19 having MUA and k wiring, 14 had a post op displacement of< 2 mm and 5 had 2–4 mm displacement. 3 of the 14(21%) had the complications of spur formation, pin site infection and wire prominence. 2/5 (40%) of those with residual displacement of 2–4 mm developed complications, 1 patient had ulceration of wires through the skin and another had loss of position requiring further surgery. In the patients treated with open reduction and wiring 51 had a residual displacement of < 2 mm, 14 had 2–4 mm residual displacement and 1 remained displaced > 4 mm. 11/51 (22%) in the first category developed complications. 6 were problems with the wires, 1 lost position requiring re-operation, 1 lateral spur development. 2 malunions and 1 delay in ossification of the lateral condyle. In the 2–4 mm group 8/14 (57%) developed complications. – 2 wire ulcerations, 2 wound infections, 1 non-union and 3 malunions. Finally the 1 patient with residual displacement > 4 mm developed a malunion requiring further operative intervention. In total 5 patients had further surgery - 1 patient for wire prominence 2 for loss of position and 2 patients required corrective surgery for malunion. Conclusion: This study highlights the variety in treatment methods for these fractures. Complications occurred in all treatment groups. The short term complications such as wire problems and initial loss of position had no long term sequelae. All malunions occurred in the open reduction and wiring group, despite 2 patients having post operative fracture displacement of < 2 mm. The patient with a non union was a late referral but underwent open reduction and wiring at our unit and subsequently healed. We recommend that displaced fractures should be reduced either closed or open and all fractures should be secured with k wires to prevent loss of position. These should be bent and buried allowing them to remain insitu for 3 months. Postoperative casting should be for 6 weeks. These fractures need to be followed closely at fracture clinic for the short and long term problems they can develop

Purpose of the study: Fracture of the medial condyle of the humerus is uncommon in adults. The purpose of this retrospective analysis was to examine the clinical and radiographic outcomes of a single-site series. Material and methods: From January 1990 to December 2004, nine closed fractures of the medial condyle of the humerus were treated surgically in seven men and two women, mean age 31.22 years (range 16–65). No vessel or nerve injury was noted at diagnosis. According to the AO/ASIF classification, all fractures were type B2. Surgery was undertaken on day 2 to 6, via a medial or posterior approach for pin or screw fixation. Postoperatively, the joint was held immobile with a brace for 5.57 weeks (3–8.). Functional and physical outcome were studied using the Mayo Clinic Elbow Performance score. Bone healing and secondary osteoarthritis were assessed on plain x-rays. Results: Six patients were reviewed at mean follow-up of 9.31 years (4.31–16.56), three patients were lost to follow-up. There were no infections. Four patients experienced sensorial disorders in the territory of the ulnar nerve including three with persistent symptoms at last follow-up. Two elbows were slightly painful at last follow-up. Two patients aged 16 and 18 years at trauma exhibited exaggerated valgus. Material was removed for three patients. Mean flexion was 123.83 (90–140), mean extension deficit 3.33 (−10 to 0), mean pronation 82.5 (70–85), mean supination 90, the flexion-extension range 122.16 (90–130). The Mayo Elbow Performance Score was 89.16 (65–100), one patient was dissatisfied, three patients exhibited moderated joint impingement. Hypertrophy of the medial condyle was noted in three patients. All fractures healed. Discussion: These fractures are rare in adults. Few series are reported in the literature, with small populations. The mechanism of the injury can be direct shock on a flexed elbow or indirect shock by fall onto the hand. Valgus deviation and hypertrophy of the medial condyle in adolescents appear to be secondary to secondary growth stimulation. The combination of the initial injury, imperfect reduction, and prolonged postoperative immobilization influences the functional outcome. Conclusion: This work confirms that surgery alone, associating perfect reduction and rigid fixation, can enable early rehabilitation and improved results

Introduction: Fracture of the lateral condyle of distal humerus in the pediatric population is a common problem. In children less than 13 year the distal humerus is only partially ossified and it is sometimes impossible to assess whether a fracture extends to the articular surface of distal humerus and whether or not there is a step off. Classic recommendations were to perform an open reduction in order to ensure perfect reduction. There are sporadic reports on use of arthrography or MRI studies. Aim of the Study: Retrospective study- intended to evaluate the clinical and radiographic outcome in children in whom the articular surface of distal humerus was evaluated by arthrography . Uppon arthrography results undisplaced fractures were percutaneously pinned and displaced fractures underwent formal open reduction and internal fixation. Patients and Methods: 11 children mean age 7.8 (1.5–15) were enrolled in the study. Inclusion criteria was a fracture of lateral condyle of humerus suspected to be type II according to Jakob (the fracture is complete but is not diplaced out of the elbow joint). The mean follow up was 2.4y (13m-5.2y). Range of motion. Carrying angle were and neurovascular status were noted and compared with controlateral elbow. Actual X-rays were reviewed. Results: The patient sample represent around 8% of the whole number of children treated in our Institution during 2000–2005. In 7 patients we were able to avoid open reduction and still to achieve excellent results. In 4 cases that were finally managed by open reduction the intraoperative findings fitted the arthrographic findings. In Conclusion: Arthrography may prevent unnecessary open reductions for lateral condyle fractures in children

Previously more femoral rollback has been reported in posterior-stabilized implants, but so far the kinematic change after post-cam engagement has been still unknown. The tri-condylar implants were developed to fit a life style requiring frequent deep flexion activities, which have the ball and socket third condyle as post-cam mechanism. The purpose of the current study was to examine the kinematic effects of the ball and socket third condyle during deep knee flexion. The tri-condylar implant analyzed in the current study is the Bi-Surface Knee System developed by Kyocera Medical (Osaka, Japan). Seventeen knees implanted with a tri-condylar implant were analyzed using 3D to 2D registration approach. Each patient was asked to perform a weight-bearing deep knee bend from full extension to maximum flexion under fluoroscopic surveillance. During this activity, individual fluoroscopic video frames were digitized at 10°increments of knee flexion. A distance of less than 1 mm initially was considered to signify the ball and socket contact. The translation rate as well as the amount of translation of medial and lateral AP contact points and the axial rotation was compared before and after the ball and socket joint contact. The average angle of ball and socket joint contact were 64.7° (SD = 8.7), in which no separation was observed after initial contact. The medial contact position stayed from full extension to ball and socket joint contact and then moved posteriorly with knee flexion. The lateral contact position showed posterior translation from full extension to ball and socket joint contact, and then greater posterior translation after contact (Figure 1). Translation and translation rate of contact positions were significantly greater at both condyles after ball and socket joint contact. The femoral component rotated externally from full extension to ball and socket joint contact, and then remained after ball and socket joint contact (Figure 2). There was no statistical significance in the angular rotation between ball and socket joint contact and maximum flexion. Translation of angular rotation was significantly greater before ball and socket joint contact, however, there was no significance in translation rate before and after ball and socket joint contact. The ball and socket joint was proved to induce posterior rollback intensively. In terms of axial rotation, the ball and socket joint did not induce reverse rotation, but had slightly negative effects after contact. The ball and socket provided enough functions as a posterior stabilizing post-cam mechanism and did not prevent axial rotation

Purpose We report the long term outcome of a minimally invasive technique avoiding the risks associated with open reduction and bone grafting in paediatric lateral condyle fracture non-unions. Methods The Toronto Hospital for Sick Children's radiology database was searched to isolate all those who sustained a lateral condyle elbow fracture and had developed a non-union between the years 1998 and 2008. This identified 16 patients who had undergone percutaneous fixation for the treatment of their non union. Each individuals clinical notes and radiographs were reviewed from presentation to final follow-up. Results Median age at injury was 5.1 (3.2, 7.2) in the successful and 2.8 (2.1, 4.7) in the unsuccessful groups (p=0.18). 11 patients (68.7%) had been initially managed non-operatively. Median time from injury to non-union diagnosis was 15.7 weeks in the successful, and 225.5 weeks in the unsuccessful group (p=0.039). Mean time to union post fixation was 16.2 weeks (+/- 6.74) and mean time to surgery was 5.2 weeks (+/- 4.11). Surgery was successful, defined as radiological and clinical union, in 12 of 16 patients (75%). 43.8% had metalwork removal and no cases of avascular necrosis were reported. Conclusion We have demonstrated this technique to be successful in those non-unions addressed within 16 weeks from initial injury to diagnosis. We had 4 failures, these occurred in patients whose non-unions were diagnosed more than 31 weeks from the time of injury (31; 68; 383; 427 weeks). Each of these failures had been managed non-operatively as part of their primary treatment plan. Percutaneous fixation is feasible and safe. Patients not achieving union were diagnosed significantly later. There was a trend towards successfully treated patients being younger

Purpose of the study: TKA on genu valgum raises serious problems for the ligament balance. Excessive release of the lateral retracted ligaments exposes the knee to potential instability in the frontal plane. To resolve this problem and avoid implantation of a constrained TKA, we opted for osteotomy of the lateral condyle removing the insertion of the lateral collateral ligament and the popliteal muscle after release of the fascia lata. The purpose of our study was to evaluate the functional and radiographic outcomes of these patients. Material and methods: This was a retrospective study from 2002 to 2006. All patients with degenerative joint disease of the knee with severe and/or fixed genu valgum were included. These patients were implanted with a navigated posterostabilised Wallaby TKA (Navitrack) associated with osteotomy of the lateral condyle fixed with screws after acquisition of the ligament balance. The diagnosis and surgical history were noted. The preoperative alignement was determined on the full limb x-ray and from navigation data. The following variables were reviewed: polyethylene height, lowering of the lateral condyle, blood loss, operative time. The postoperative alignment was established at least one year after surgery. Intraoperative, postoperative and late complications were noted. The Knee Society function scores were used. Results: Fifteen patients, mean age 70 years were reviewed at mean 35 months. The mean duration of the operative time was 136 min with mean blood loss of 620 ml. The mean PE height was 13 mm. All operated knees were corrected with mean alignment improving from 17.71 to 1.5 valgus postoperatively. The function score improved from 35 preoperatively to 79 at last follow-up. There were no cases of patellar instability or secondary laxity. Two patients developed late reflex dystrophy. The only case of revision concerned one non-union of the lateral condyle (screw removed at four months) but had a function score of 85 at last follow-up. Discussion: Performing an osteotomy of the lateral condyle in complement with the navigated posterostabilised TKA for fixed genu valgum enabled good relaxation and satisfactory functional results so that totally constrained implants can be avoided

Wear of the polyethylene (PE) insert in total knee replacements can lead to wear-particle and fluid-pressure induced osteolysis. One major factor affecting the wear behaviour of the PE insert in-vivo is the surface characteristics of the articulating femoral components. Contemporary femoral components available in Canada are either made of cast Cobalt Chromium (CoCr) alloy or have an oxidized zirconium surface (Oxinium). The latter type of femoral components have shown to have increased abrasive wear resistance and increased surface wettability, thus leading to reduced PE wear in-vitro compared with conventional cast CoCr components. Although surface damage has been reported on femoral components in general, there have been no reports in the literature as to what extent the recommended operating techniques affect the surface tribology of either type of femoral component. Twenty-two retrieved total knee replacements were identified with profound surface damage on the posterior aspect of the femoral condyles. The femoral components were of three different knee systems: five retrievals from the NexGen(r) total knee system (Zimmer Inc., Warsaw, IN), twelve retrievals from the Genesis II(r) total knee system (CoCr alloy or Oxinium; Smith & Nephew Inc., Memphis, TN), and five retrievals from the Duracon(r) total knee system (Stryker Inc., Mahwah, NJ). Reasons for revision were all non-wear-related and included aseptic loosening in two cases, painful flexion instability, and chronic infection. All retrieved femoral components showed evidence of surface damage on the condyles, at an average of 99° flexion (range, 43° – 135° flexion). Titanium (Ti) alloy transfer and abrasive surface damage were evident on all retrieved CoCr alloy femoral components that came in contact with Ti alloy tibial trays. Surface damage on the retrieved Oxinium femoral components was gouging, associated with the removal and cracking of the oxide and exposure of the zirconium alloy substrate material. CoCr alloy femoral components that had unintended contact with CoCr alloy tibial trays also showed evidence of gouging and abrasive wear. All femoral components showed severe surface damage in the posterior aspect of the condyles. The femoral surface was heavily scratched and the oxidized zirconium coating surface appeared removed. The surface analysis suggested that the surface damage most likely occurred during the time of initial implantation. In particular, it appeared that the femoral condyles were resting on the posterior aspect of the tibial tray in flexion, thus scratching the femoral components. Such scratches could potentially lead to accelerated PE insert wear and reduced implant longevity, thus making expensive revisions surgery necessary. The authors strongly suggest a revision of the current operating techniques recommended by the implant manufacturer to prevent this type of surface damage from occurring

Introduction. An equal knee joint height during flexion and extension is of critical importance in optimizing soft-tissue balancing following total knee arthroplasty (TKA). However, there is a paucity of data regarding the in-vivo knee joint height behavior. This study evaluated in-vivo heights and anterior-posterior (AP) translations of the medial and lateral femoral condyles before and after a cruciate-retaining (CR)-TKA using two flexion axes: surgical transepicondylar axis (sTEA) and geometric center axis (GCA). Methods. Eleven patient with advanced medial knee osteoarthritis (age: 51–73 years) who scheduled for a CR TKA and 9 knees from 8 healthy subjects (age: 23–49 years) were recruited. 3D models of the tibia and femur were created from their MR images. Dual fluoroscopic images of each knee were acquired during a weight-bearing single leg lunge. The OA knee was imaged again one year after surgery using the fluoroscopy during the same weight-bearing single leg lunge. The in vivo positions of the knee along the flexion path were determined using a 2D/3D matching technique. The GCA and sTEA were determined based on existing methods. Besides the anterior-posterior translation, the femoral condyle heights were determined using the distances from the medial and lateral epicondyle centers on the sTEA and GCA to the tibial plateau surface in coronal plane (Fig. 1). The paired t-test was applied to compare the medial and lateral condyle motion within each group (Healthy, OA, and CR-TKA). Two-way ANOVA followed post hoc Newman–Keuls test was adopted to detect significant differences among the groups. p<0.05 was considered significant. Results. The results demonstrated that following TKA, the medial and lateral femoral condyle heights were not equal at mid-flexion (15° to 45°, medial condyle lower then lateral by 2.4mm at least, p<0.01), although the knees were well-balanced at 0° and 90° (Fig. 2). While the femoral condyle heights increased from the pre-operative values (>2mm increase on average, p<0.05), they were similar to the intact knees except that the medial sTEA was lower than the intact medial condyle between 0 and 90°. At deep flexion (>90°), both condyles were significantly higher (>2mm, p <0.01) than the healthy knees. Anterior femoral translation of the TKA knee was more pronounce at mid-flexion (Fig. 3), whereas limited posterior translation was found at deep flexion. Conclusion. Femoral condyle heights and AP translations of the CR TKA knees were significantly different from the healthy knees during the weight bearing flexion activity when measured using both the sTEA and GCA, especially at mid-flexion (15° to 45°) and deep flexion (>90°). These results suggest that a well-balanced knee intra-operatively might not necessarily result in mid-flexion and deep flexion balance during functional weight-bearing motion, implying mid-flexion instability and deep flexion tightness of the knee. The data could be useful for improvement of future prostheses designs and surgical techniques in treatment of patients with end-stage medial knee OA

Aims: We wanted to compare bioactive glass granules with autogenous bone in operative treatment of lateral condyle fractures. Methods: 25 patients, 12 females and 13 males, (from 36 to 69 years) were operated at our institute for lateral condyle fracture. The patients were randomized into autogenous bone (AB) and bioactive glass (BG) group. There were no statistical difference between the two groups with regard to genre, patient age, type of fracture or comminution and depression of the joint surface. The study protocol was approved by the local hospital ethical committee and written consent of the patients was achieved. A routine AO operation protocol was used in all patients. Prior to operation plain x-ray þlms and three-dimensional computed tomography (3D CT) was performed in order to reveal the anatomy of the fracture. The postoperative follow-up included 3D CT, plain þlms and clinical examination after the operation and at 6 weeks, 3, 6, 12 and 36 months. Results: The mean preoperative articular depression in the BG group was 9 mm (±4 mm) and in the AB group 7mm (±2 mm). Postoperatively the articular surface remained 2 mm (± 3 mm) depressed in both groups. Threafter the articular height remained unchanged. As evaluated by CT and plain þlms the bioactive glass granules were incorporated with the surrounding bone at 3 months. No adverse reactions due to bioactive glass were observed. The clinical results were equal in both groups. Conclusions: The clinical and radiological results using bioactive glass were as good as those when autogenous bone was used

86 children with 87 lateral condyle fractures were reviewed. Excellent clinical outcomes in 88.9% of Type 1 undisplaced or < 2mm displaced fractures treated by simple cast immobilisation. In the Type 2 displaced fractures (2–3mm) treated by cast immobilisation, the risk of secondary displacement was 44%. Conclusion: Undisplaced or < 2mm displaced fracture can be treated conservatively in plaster immobilisation. For 2–3mm displaced fracture, we recommend percutaneous pinning or open reduction and Kirschner wire fixation. For displaced or rotated fractures, the fragment should be reduced anatomically and fixed with K wire until radiological union

Aims: Henri Dejour promoted a mechanism involving a third femoral condyle to achieve Posterior Stabilization (PS) in total knee arthroplasty (TKA) introducing the HLS II prosthesis. This retrospective study was conducted to assess the behavior of such PS mechanism. Methods: Between 1992 and 1993, 105 HLS II prostheses (94 patients) were consecutively inserted (78% arthrosis, 19% rheumatoid arthritis). No patient was lost for follow-up but 14 had died, 6 were unable to walk (severe neurological disorder), 4 were contacted by phone. Consequently, 70 patients (77 TKA) mean aged 66 years (22–79) were assessed after a mean follow-up of 7 years (6–8). All the components were fixed with cement and patellar resurfacing was always performed. Results: The knee IKS score increased from de 27 points [0–63] before surgery to 81 [21–100] at follow-up and functional IKS from 35 points [0–75] to 64 [0–100] (p< 0,0001). Similarly range of motion improved from 114° [60°–140°] to 116° [80°–135°] (NS). At follow-up, 86% of the patients were able to practice stairs (13% without support and 28% in alternative manner) against 52% before surgery (1% without support and 1% in alternative manner) (p=0,001). Tibial bone-cement radiolucencies were observed without loosening in 30% (all < 1 mm and non- progressive) mainly related to severe preoperative varus deformation (p = 0.01). One late infection required reoperation. Ninety months survival was 97% ± 1.3% with reoperation related to infection or mechanical disorder as end-point. Conclusion: The posterior stabilization, by means of a third condyle, allowed a satisfactory range of flexion and improved ability to practice stairs. Mid-term follow-up did not identified adverse effects of this PS mechanism on component fixation or knee stability

Background: The Profix Total Knee Arthroplasty (Smith and Nephew, Memphis, USA) is designed to replace less bone than is resected from the posterior femoral condyles, and as a consequence the posterior condylar offset is reduced. The net effect of this is to increase the flexion gap with no effect on the extension gap. This is a deliberate design philosophy aimed at increasing postoperative flexion. This prospective cohort study has tested this theory.

Methods: 60 patients underwent primary posterior cruciate retaining (CR) TKA using this prosthesis. A matched group of patients, employing a different CR prosthesis which replaces excised bone in full, served as historical controls. Intra-operative measurements were made of the posterior condylar bone resected in each case. These measurements were then correlated with the flexion achieved both intra-operatively and at 6 months post-operatively.

Results: A positive correlation between pre-operative and post-operative flexion was found. However, there was no correlation between the relative increase in flexion gap secondary to the reduction in posterior offset and the resulting flexion range.

Conclusion: Post-operative flexion range is not increased by the resection of more bone from the posterior femoral condyles than is replaced by the prosthesis in TKA. The loss of bone stock will have implications for revision surgery and should be avoided.

Cartilage diseases have a significant impact on the patient's quality of life and are a heavy burden for the healthcare system. Better understanding, early detection and proper follow-up could improve quality of life and reduce healthcare related costs. Therefore, the aim of this study was to evaluate if difference between osteoarthritic (OA) and non-osteoarthritic (non-OA) knees can be detected quantitatively on cartilage and subchondral bone levels with advanced but clinical available imaging techniques. Two OA (mean age = 88.3 years) and three non-OA (mean age = 51.0 years) human cadaveric knees were scanned two times. A high-resolution peripheral quantitative computed tomography (HR-pQCT) scan (XtremeCT, Scanco Medical AG, Switzerland) was performed to quantify the bone microstructure. A contrast-enhanced clinical CT scan (GE Revolution Evo, GE Medical Systems AG, Switzerland) was acquired with the contrast agent Visipaque 320 (60 ml) to measure cartilage. Subregions dividing the condyle in four parts were identified semi-automatically and the images were segmented using adaptive thresholding. Microstructural parameters of subchondral bone and cartilage thickness were quantified. The overall cartilage thickness was reduced by 0.27 mm between the OA and non-OA knees and the subchondral bone quality decreased accordingly (reduction of 33.52 % in BV/TV in the layer from 3 to 8 mm below the cartilage) for the femoral medial condyle. The largest differences were observed at the medial part of the femoral medial condyle both for cartilage and for bone parameters, corresponding to clinical observations. Subchondral bone microstructural parameters and cartilage thickness were quantified using in vivo available imaging and apparent differences between the OA and non-OA knees were detected. Those results may improve OA follow-up and diagnosis and could lead to a better understanding of OA. However, further in vivo studies are needed to validate these methods in clinical practice

Total temporomandibular joint (TMJ) replacements reduce pain and improve quality of life in patients suffering from end-stage TMJ disorders, such as osteoarthritis and trauma. Jaw kinematics measurements following TMJ arthroplasty provide a basis for evaluating implant performance and jaw function. The aim of this study is to provide the first measurements of three-dimensional kinematics of the jaw in patients following unilateral and bilateral prosthetic TMJ surgeries. Jaw motion tracking experiments were performed on 7 healthy control participants, 3 unilateral and 1 bilateral TMJ replacement patients. Custom-made mouthpieces were manufactured for each participant's mandibular and maxillary teeth, with each supporting three retroreflective markers anterior to the participant's lip line. Participants performed 15 trials each of maximum jaw opening, lateral and protrusive movements. Marker trajectories were simultaneously measured using an optoelectronic tracking system. Laser scans taken of each dental plate, together with CT scans of each patient, were used to register the plate position to each participant's jaw geometry, allowing 3D condylar motion to be quantified from the marker trajectories. The maximum mouth opening capacity of joint replacement patients was comparable to healthy controls with average incisal inferior translations of 37.5mm, 38.4mm and 33.6mm for the controls, unilateral and bilateral joint replacement patients respectively. During mouth opening the maximum anterior translation of prosthetic condyles was 2.4mm, compared to 10.6mm for controls. Prosthetic condyles had limited anterior motion compared to natural condyles, in unilateral patients this resulted in asymmetric opening and protrusive movements and the capacity to laterally move their jaw towards their pathological side only. For the bilateral patient, protrusive and lateral jaw movement capacity was minimal. Total TMJ replacement surgery facilitates normal mouth opening capacity and lateral and inferior condylar movements but limits anterior condylar motion. This study provides future direction for TMJ implant design

Abstract. Background. Conventional TKR aims for neutral mechanical alignment which may result in a smaller lateral distal femoral condyle resection than the implant thickness. We aim to explore the mismatch between implant thickness and bone resection using 3D planning software used for Patient Specific Instrumentation (PSI) TKR. Methods. This is a retrospective anatomical study from pre-operative MRI 3D models for PSI TKR. Cartilage mapping allowed us to recreate the native anatomy, enabling us to quantify the mismatch between the distal lateral femoral condyle resection and the implant thickness. Results. We modelled 292 knees from PSI TKR performed between 2012 and 2015. There were 225 varus knees and 67 valgus knees, with mean supine hip-knee-angle of 5.6±3.1 degrees and 3.6±4.6 degrees, respectively. In varus knees, the mean cartilage loss from medial and lateral femoral condyle was 2.3±0.7mm and 1.1±0.8mm respectively; the mean overstuffing of the lateral condyle 1.9±2.2mm. In valgus knees, the mean cartilage loss from medial and lateral condyle was 1.4±0.8mm and 1.5±0.9mm respectively; the mean overstuffing of the lateral condyle was 4.1±1.9mm. Conclusions. Neutral alignment TKR often results in overstuffing of the lateral condyle. This may increase the patello-femoral pressure at the lateral facet in flexion. Anterior knee pain may be persistent even after patellar resurfacing due to tight lateral retinacular structures. An alternative method of alignment such as anatomic alignment may minimise this problem

Distal femur fractures (DFF) are common, especially in the elderly and high energy trauma patients. Lateral locked osteosynthesis constructs have been widely used, however non-union and implant failures are not uncommon. Recent literature advocates for the liberal use of supplemental medial plating to augment lateral locked constructs. However, there is a lack of proprietary medial plate options, with some authors supporting the use of repurposing expensive anatomic pre-contoured plates. The aim of this study was to investigate the feasibility of a readily available cost-effective medial implant option. A retrospective analysis from January 2014 to June 2022 was performed on DFF (primary or revision) managed with supplemental medial plating with a Large Fragment Locking Compression Plate (LCP) T-Plate (~$240 AUD) via a medial sub-vastus approach. The T-plate was contoured and placed superior to the medial condyle. A combination of 4.5mm cortical, 5mm locking and/or 6.5mm cancellous screws were used, with oblique screw trajectories towards the distal lateral cortex of the lateral condyle. All extra-articular fractures and revision fixation cases were allowed to weight bear immediately. The primary outcome was union rate. This technique was utilised on sixteen patients; 3 acute, 13 revisions; mean age 52 years (range 16-85), 81% male, 5 open fractures. The union rate was 100%, with a median time to union of 29 weeks (IQR 18-46). The mean follow-up was 15 months. There were two complications: a deep infection requiring two debridements and a prominent screw requiring removal. The mean range of motion was 1–108. o. . Supplemental medial plating of DFF with a Large Fragment LCP T-Plate is a feasible, safe, and economical option for both acute fixation and revisions. Further validation on a larger scale is warranted, along with considerations to developing a specific implant in line with these principles