The various disorders of the patellofemoral joint, from pain syndrome to maltracking and arthritis, form a significant subset of knee disorders (Callaghan and Selfe 2007). Several studies have shown significant geography and gender based variation in incidence rates of these disorders and of osteoarthritis in general (Woolf 2003). A number of previous studies have examined patellar shape in this context, focusing primarily on the use of 2D measurements of bony geometry to classify patellar shapes and identify high-risk groups (Baumgartl 1964; Ficat 1970).

Recent developments in imaging and statistical analysis have enabled a more sophisticated approach, characterised by statistical shape models which account for three dimensional shape differences (Bryan 2008). Incorporating soft tissue data into these analyses, however, has been a challenge due to factors including the necessity of multi-modality images, absence of repeatable landmarks, and complexity of the surfaces involved. We present here a novel method which has potential to significantly improve analysis of soft tissue geometry in joints. It is built using Arthron, a UCD-developed biomechanics analysis software package.

The shape modelling process consists of three phases: pre-processing, consistent surface parameterization, and statistical shape analysis. The pre-processing phase consists of several mesh processing operations that prepare the input surfaces for shape modelling. Consistent surface parameterizations are implemented using the minimum description length (MDL) correspondence method (Davies 2002) [Fig. 1]. The statistical shape analysis phase involves the reporting and visualization of geometric variation at the input surface. An algorithm was developed to measure the cartilage thickness at each node on the patellar surface mesh. The initial step in this process was to calculate surface normal vectors at each point. These vectors were then projected through the cartilage surface model in order to calculate the thickness [Fig. 2]. The Matlab software was used to aggregate all cartilage thickness values in a given subgroup and after being normalised for the average patellar centroid size for the subgroup, these thicknesses were visualised on the average shape.

Pilot study data consisted of 19 Caucasian (7 female, 12 male) and 13 Japanese (7 female, 6 male) subjects. These data originated from studies performed by DePuy Orthopaedics Inc. Initial results show ethnicity effects in cartilage thickness to be more significant than gender effects [Fig. 3]. After correcting for patellar centroid size, male subjects display 9% greater average thickness than female subjects, while Caucasian subjects display 17% greater average thickness than Asian subjects. Areas of statistically significant differences (t < 0.05) were found to coincide with expected areas of patellofemoral contact through the flexion cycle, showing the potential for the thickness differential to impact upon patellar kinematics. Principal component analysis of the thickness distributions gives more detailed information about modes of variation.

With further development, this method has potential to enable sophisticated analysis of localised variation in soft tissue geometry, thereby improving understanding of the impact of joint geometry on disease formation.

Previous in vivo studies have not documented if ethnicity or gender influence knee kinematics for the healthy knee joint. Other measurements, such as hip-knee-ankle alignment have been previously shown to be significantly different between females and males, as well as Japanese and Caucasian populations in the young healthy knee [1]. Differences in knee kinematics in high flexion positions may relate to both etiology of osteoarthritis and success in knee replacement designs. Although differences in knee anatomy have been identified, their significance in knee function has not yet been clarified. Therefore, the objective of this study was to determine the 3D, in vivo normal knee kinematics for various subjects from different gender and ethnic backgrounds, and to identify significant differences, if any, between populations.

The 3D, in vivo, weight bearing normal knee kinematics was determined for 79 healthy subjects, including 48 Caucasians, 24 Japanese, 42 males, and 37 females. Each participant performed deep knee bend activity from a standing (full extension) to squatting to a lunge motion, until maximum knee flexion was reached. The study was approved by the Institutional Review Board and informed consent form was obtained from all subjects. The 3D bone models, created by segmentation from MR images, were used to recreate the 3D knee kinematics using the previously described fluoroscopic and 3D-to-2D registration techniques (Fig. 1) [2,3]. Tibiofemoral rotations were described using the ISB recommended Grood and Suntay convention [4,5]. Anterior-posterior translations of the centers of the posterior femoral condyles were normalized due to significantly different anthropometry in the subjects. Anterior cruciate ligament (ACL) laxity was also measured using a KT-1000 device for 72 of these subjects. Statistical analysis was performed using the Student’s t-test, set at the 95% confidence interval.

Most subjects achieved very high flexion, however substantial variability occurred in all groups. Range of motion (ROM) varied from 117° to 177°, while average external rotation was 31°± 9.9° for all subjects. Japanese and female subjects achieved greater ROM than Caucasian (p=0.048) and male (p=0.014) subjects. From full extension to 140° of flexion (which 87% of subjects achieved), few significant differences between any of the populations were observed. At deeper flexion, the external rotation was higher for female than for male subjects, however not statistically significant (p=0.0564 at 155°). Also at deep flexion, the adduction was significantly higher for female subjects. The translations of the lateral condyle were very similar between respective groups, but at deep flexion, the medial condyle remained significantly more anterior for females, leading to greater axial rotation and ROM. As ACL laxity increased, flexion/extension ROM significantly increased (r2=0.184, p< 0.001). In addition, ACL laxity was also higher for females (6.8 mm) compared to males (5.6 mm, p=0.011), as well as Japanese (7.5 mm) compared to Caucasian (5.6 mm, p=0.0002) subjects.

High variability and ROM in knee kinematics were similar to those seen in previous studies of healthy subjects during a deep knee bending activity [6]. Subjects in this study achieved much greater axial rotation and ROM than previously analyzed TKA patients. A relationship was found between greater axial rotation and increased ROM, and may be related in part to increased ACL laxity in the knee. Significant differences in ROM and laxity were identified between genders and ethnic groups. Also the medial condyle remaining significantly more anterior for females than for males in deep flexion may explain higher external rotation and consequently higher flexion experienced by women. However, understanding the causes for variability within each group may be the key to improved implant design.

Introduction: Tibial plateau fracture is an intra-articullar complex fracture. Surgery aim is to restore articular surface height, preserve knee joints stability and alignment in order to obtain maximal range of motion and to prevent future joint degenerative changes. Ilizarov external frame using ligamentotaxis, minimal invasive techniques, smooth or olive wires (sometimes augmented by screws) allows articular surface reconstruction and stabilization. In unstable fractures, bridging of the knee with slight distraction of the joint is provided by including the distal femur to the frame with an additional ring.

Study Aims: To assess the results of complex tibial plateau fracture treated with Ilizarov external fixator.

Materials and Methods: Between 1997–2005, twenty five patients with complex fractures of the tibial plateau, Schatzker type V–VI fractures (all closed), average age 45 years old (range 30–78) were treated by hybrid 3 ring Ilizarov external frames alone or in combination with another procedure. 11 out of 25 patients were treated with ligamentotaxis using extension of the frame to the femur with hinges on the center of joint rotation. Some of these patients (10 out of 11) required lateral minimal opening for joint surface elevation. 8 out of the 25 patients needed additional bone graft/ substitute supplementation. One needed 6.5 mm canulated cancellous screw augementation. Patients with below knee frame remain non-WB for 6 weeks and partial WB for another 6 weeks. Patients with above knee frame were allowed full WB. In 3 months the frame was removed under anesthesia and the knee was manipulated. Patients were placed in a brace or a cast-brace with full WB. Physiotherapy started early after the operation.

Results: All fractures united with an average time of 12 weeks. 22 patients had full extension with 100 degree of flexion or more. 3 patients had extension lag of 10–20 degree, one of them had 20 degree of posterior slop of the tibial plateau. All patients had normal axial alignment, except one case resulted in mild valgus alignment due to osteoporotic bone (70 years old patient). One had mild unstable knee. One patient developed posttraumatic osteoarthrosis. There were no cases of postoperative infection, septic arthritis or neuro-vascular complications were reported. Pin site infection was resolved locally.

Conclusion: The use of Ilizarov external fixation in the management of complex tibial plateau fractures results in satisfactory out come as an alternative to the traditional tibial plateau open surgery. This minimal invasive intervention allowed the surgeons to reduce and fixate the tibial articular surface with out further damaging the soft tissue envelope.

Introduction: Fractures of the elbow constitute about 7% of adult fractures; distal humerus fractures account for less than half of all elbow fractures.

There is evidence, however, that incidence is increasing.

Investigators in Finland performed a retrospective review of hospital admission records between 1970 and 1995 and found that the age-adjusted increase in incidence in women older than 60 years had more than doubled.

Treatment of intraarticular comminuted distal humeral fractures is a surgical challenge, adequate reduction of the joint surface demands avoidance of residual step or gap of the articular surface and providing a stable fracture fixation.

Aim: To evaluate our initial experience in internal fixation by using bioabsorbable screws by treatment of patients suffered from comminuted distal humeral fractures.

Material and methods: 5 patients with sever intraarticular comminuted distal humeral fractures were treated using bioabsorbable screws. A standard transolecranon approach was used. Internal fixation was performed using lateral and medial plates. Additional bioabsorbable screws (pins) were used to fix separate intraarticuar fragments of the distal humeral bone.

Results: By follow up all fractures were healed with out secondary displacement of fractures. All five patients returned to the preoperative activity, ROM of operated joints was in functional limits. Insertion bioabsorbable screws thorough articular surface allows preserve intraarticular bone fragments on the place until solid consolidation without need in additional operative procedure of removing implanted devices.

Conclusion: Our experience suggests that the bioabsorbable screws can serve as useful augmentation in surgical repair of severe intraarticular comminuted fractures of the elbow joint. Future clinical study

Recently, secondary life-threatening inflammatory reactions have been identified with molecular biological techniques in patients with multi-system injuries who were submitted to immediate or early intramedullary fixation of their fractured femora. This phenomenon was called “The second hit”, and it caused ARDS, PE, and Renal Failure.

In a consecutive series of 135 trauma patients with high energy long bone fractures, 40 had sustained multiple-injuries. All fractures were reduced and stabilized on admission by AO-Tubular External Fixation systems. After 72–96 hours, this system was converted to an hybrid-ring-tubular system, which had three dimensional stability. They commenced partial weight bearing 24 hours later, and were followed by bony union.

One patient developed DVT, none developed ARDS, PE, Renal Failure.

Superficial pin-tract infection was common, but no-deep infection and’or osteomyelitis were encountered.

With this minimal-invasive surgical technique, life threatening complications were avoided while preserving the integrity of the soft tissue envelope, the critical contributing biological factor for fracture healing.

Purpose: The purpose of this study is to evaluate the results of the treatment by severe blast injuries to limbs.

Materials and methods: Twenty-seven patients after blast injuries were treated. There were 13 patients with tibial fractures, 7 fractures of the femur, 4 – fractures of the humerus and 3 with fractures of the forearm bones. According to Gustilo all fractures were open grade 3B and 3C. According to MESS a median value was 4,7 points (range 3 – 7). Six had on admission vascular injuries, and 12 had peripheral nerve injuries. There was other major organ trauma in 55,5% of patients.

On admission, the fractured bones are realigned and stabilized with an AO tubular external fixation frame followed by immediate thorough soft tissue debridement, vascular reconstruction. In patients with peri-articular fractures temporary trans-articular bridging was needed.

After 5 to 7 days or when wound condition permits, delayed primary sutures, the application of skin grafts or free tissue flaps are performed. At this stage, the tubular fixator is exchanged for a circular frame that allows stability, sufficient for full weight bearing by minimal invasive fixation and meticulous attention to freeing the previously bridged joints. Hybrid frames allows combination of advantages of each type of external fixators. Closed reduction of fractures was performed in most patients by ligamentotaxis and use thin wires with olives. Fixation in elastic frame combined with cyclic loading provide favorable biomechanical environment for fracture healing.

In patients with high-energy “floating elbow” injuries the hybrid circular devices of the humerus and forearm were connected by hinges to allow immediate elbow joint movements. The separate fixation of the forearm bones was performed to allow early pronation/supination motions.

Results: In all patients the external fixation was the definitive treatment. Fracture union was achieved at median time of 240 days (range 90 – 546). Throughout the period of fracture healing the patients were fully ambulatory, living at home. In three patients with bilateral highly complex blast injuries of lower extremities, where one limb had to be amputated, the Ilizarov device for severely injured contralateral limb provided the conditions necessary for early prosthetic fitting. There was one non-union and one patient developed chronic osteomyelitis treated by serial debridement and sequestrectomies.

Conclusions: Based on this experience, we suggest that the stabilization in ring frame with radical debridement and early tissue transfer provides fracture healing and good functional results in extensive compound blast injuries of the extremities even in limbs categorized as high risk.

Aims: To evaluate the clinical outcome of the treatment of severe high-energy war injuries to limbs using circular external þxation frames. Metods: 43 patients after war injuries with 57 high-energy fractures were treated. According to Gustilo and Anderson all fractures were open grade 3B and 3C. There was other major organ trauma in 52,8% of patients. On admission, the fractured bones were stabilized with an AO tubular external þxation frame followed by thorough extensive soft tissue debridement, vascular reconstruction if needed. After 5 to 7 days the tubular þxator is exchanged for a circular frame that allows receiving stability, sufþcient for full weight bearing by minimal invasive þxation and freeing the previously bridged joints, in order to preserve their range of movement. Closed reduction of fractures was performed in most patients by successful implementation of ligamentotaxis and use thin wires with olives. In patients with high-energy Ç ßoating joint È injuries the circular devices were connected by hinges to permit early initiation of joint motions and functional treatment. In patients with upper limb injuries a separate bone þxation was used to allow early ßexion/ extension and pronation/supination motions. Results: In all patients the circular external þxation was the deþnitive treatment. Bone grafting was not necessary in any patient because of compression-distraction possibility. Fracture union was achieved at median time of 8 months (range 3 60). Throughout the period of fracture healing the patients were ambulatory, living at home. Conclusion: The circular þxation frame allows perform successful skeletal stabilization and functional restoration of limbs in patients with extensive bone and soft tissue loss, even in limbs of the risk.