[Distal femoral osteotomy using a lateral opening wedge technique]. / Distale Femurosteotomie in lateraler Open-wedge-Technik.

OBJECTIVE: To shift the weight-bearing axis of the lower limb medially by opening a lateral-based metaphyseal osteotomy at the distal femur. INDICATIONS: Femoral-based valgus malalignment and symptomatic lateral unicompartimental osteoarthritis, lateral hyperpression syndrome, cartilage therapy of the lateral compartment, lateral meniscal replacement/transplantation, medial instability with valgus thrust, reconstruction of the medial collateral ligament, patellar instability and/or maltracking. CONTRAINDICATIONS: Advanced cartilage damage (>grade 2) or subtotal meniscal loss of the medial compartment, age >65 years (relative), nicotine abuse, body mass index >30, flexion contracture >25°, corrections with a wedge base >10 mm in case of congenital deformities, inflammatory or septic arthritis, severe osteoporosis. SURGICAL TECHNIQUE: Lateral approach to the distal femur; biplanar osteotomy (frontal + axial osteotomy), gradual opening of the osteotomy, osteotomy fixation with a locking plate. POSTOPERATIVE MANAGEMENT: Free range of motion. Partial weight bearing with 20 kg for 2 weeks, followed by progressive weight bearing thereafter. RESULTS: Mean improvement of knee scores from 20-30 points and mean 10-year survival rate of 80% in patients with lateral unicompartimental osteoarthritis. Mean complication rate of 9%.

[Positive and negative predictors of long-term results after an osteotomy around the knee joint]. / Positive und negative Prädiktoren für das Langzeitresultat nach kniegelenknaher Osteotomie.

A frequently asked question in the context of any surgical procedure, including an osteotomy around the knee joint, is "which parameters are in favor of a therapeutic success in this special case?" If the analysis of the leg geometry is in favor of an osteotomy, then the patient must be assessed further, taking into account the joint status and patient's condition. Positive outcome predictors for long-term success of an osteotomy around the knee, especially for a valgus osteotomy at the tibia are a tibial bone varus angle (TBVA) > 3-5°, knee joint range of motion > 100° flexion, male sex, and a BMI < 30. It is unclear whether the degree of degeneration of the affected (medial) compartment is of special relevance. The severity of malalignment, the patient's sex, and psychopathological comorbidities are not important.

Functional outcome after transphyseal anterior cruciate ligament reconstruction in young patients with open growth plates.

BACKGROUND: This study evaluates sports ability, rotational laxity and potential growth changes in children after transphyseal ACL reconstruction with metaphyseal fixation technique, considering physis biology by placing drill holes vertically in the femoral anatomic origin in order to reduce volumetric injury to the physis. METHODS: In this retrospective trial of 42 patients data were collected. Thirty-seven were reviewed measuring rotational laxity and anteroposterior tibial translation using the Laxitester (ORTEMA Sport Protection, Markgroeningen, Germany) and the KT1000. Clinical examination was evaluated with the IKDC 2000 knee examination form. Leg axis was determined with digital photography and leg length was assessed clinically. Sports ability was assessed with questionnaires including subjective IKDC, Tegner Activity Scale, Activity Rating Scale and a questionnaire on sports and level of sports. RESULTS: Mean follow-up was 24.9months. Mean age at surgery was 13.2years in boys and 13.1years in girls. IKDC 2000 grading was A or B in 28 patients and C in nine patients. Significant increased anterior tibial translation was observed in neutral position and in external tibia rotation. No growth abnormalities were seen. Fifty-seven percent of the patients were able to participate in competitive sports at follow-up. CONCLUSION: Transphyseal ACL reconstruction with metaphyseal fixation in children with open growth plates can be done with low risk of growth changes. Return to competitive sports is possible although low rotational laxity still exists. LEVEL OF EVIDENCE: IV.

[Association between Hindfoot Alignment and Localisation of Osteochondral Lesions of the Talus]. / Zusammenhang der Rückfußachse mit der Lokalisation von osteochondralen Läsionen am Talus.

BACKGROUND: Osteochondral lesions (OCL) of the talus show a distinct distribution pattern. Vascular, metabolic, idiopathic, and biomechanical factors have been proposed as influencing factors. However, the association of hindfoot alignment and the location of talar OCL is not known. MATERIALS AND METHODS: In 22 patients undergoing autologous osteochondral transplantation for OCL of the talus we collected preoperative data on radiographic hindfoot alignment and clinical performance using the AOFAS score and the VAS for pain. The inter-observer reliability between two investigators was calculated. The association between hindfoot alignment and OCL location was statistically assessed. RESULTS: The preoperative AOFAS score was 64.1 ± 13.9 points and the VAS 5.1 ± 1.4. The mean measurement difference between the two observers was less than 0.5 degrees and the reliability of the measurements was good with a high association (κ = 0.83). Surprisingly, the location of the OCL of the talus was independent from hindfoot alignment (p = 0.766). CONCLUSION: In our study the hindfoot alignment showed no association with the location of OCL of the talus. Hence, hindfoot alignment per se does not correlate with the localisation of talar OCL.

[Combination of ACL-replacement and high tibial osteotomy]. / Kombination von VKB-Ersatzplastik und hoher tibialer Umstellungsosteotomie.

OBJECTIVE: Replacement of the anterior cruciate ligament (ACL) with an autologous tendon together with a high tibial osteotomy (HTO) in one operation. INDICATION: Simultaneous symptomatic ACL insufficiency and symptomatic varus osteoarthritis. CONTRAINDICATIONS: Risk of a higher complication rate for a one-stage procedure, e.g., in loss of motion due to soft tissue contracture, loss of motion due to insufficiency of a existent ACL replacement with tunnel malplacement, tunnel widening of an existent ACL replacement with the risk of tunnel confluence, infection in a former operation. Varus osteoarthritis with a hollow posteromedial tibial plateau (knee abuser). Exclusion criteria include PLC insufficiency, lateral or posterolateral instability, lateral arthritis. SURGICAL TECHNIQUE: Osteotomy: placement of the two K-wires from the medial tibia about 4-5 cm below the medial tibial plateau towards the lateral hinge about 2 cm below the lateral tibial plateau. Mobilization of the long fibers of the medial collateral ligament distal of the osteotomy, mobilization of the pes anserinus tendons. Frontal and axial osteotomy with an oscillating saw. Completion and opening of the osteotomy with chisels. Opening of the osteotomy with a spreader according to the new leg axis of the preoperative planning. Fixation of the osteotomy with an angle stable plate (PPP Arthrex, Tomofix Synthes). In case of a distal osteotomy of the hiberosity fixation with 2 screws. Arthroscopy: positioning of a 2.4 mm K-wire in the center of the remnant femoral ACL insertion, cannulated drilling according to the graft diameter. Positioning of a 2.4 mm K-wire in the center of the remnant tibial ACL insertion, cannulated drilling. In the case of interference of the tibial tunnel with one of the osteotomy screws, removal of the screw and finishing of the tunnel preparation. Measurement of the length and insertion of the respective osteotomy screw. Insertion of the graft and fixation with a button-wire construct at the femur and with a bioabsorbable interference screw and a lag screw at the tibia. POSTOPERATIVE MANAGEMENT: Postoperative management relating to weight bearing rehabilitation follows osteotomy rules, while range of motion rehabilitation follows the ACL protocol.

Alignment does not influence cartilage T2 in asymptomatic knee joints.

PURPOSE: To investigate whether the static knee alignment affects articular cartilage ultrastructures when measured using T2 relaxation among asymptomatic subjects. METHODS: Both knee joints (n = 96) of 48 asymptomatic volunteers (26 females, 22 males; 25.4 ± 1.7 years; no history of major knee trauma or surgery) were evaluated clinically (Lysholm, Tegner) and by MRI (hip-knee-ankle angle, standard knee protocol, T2 mapping). Group (n = 4) division was as follows: neutral (<1° varus/valgus), mild varus (2°-4° varus), severe varus (>4° varus) and valgus (2°-4° valgus) deformity with n = 12 subjects/group; n = 24 knees/group. Regions of interest (ROI) for T2 assessment were placed within full-thickness cartilage across the whole joint surface and were divided respecting compartmental as well as functional joint anatomy. RESULTS: Leg alignment was 0.7° ± 0.5° varus among neutral, 3.0° ± 0.6° varus among mild varus, 5.0° ± 1.1° varus among severe varus and 2.5° ± 0.7° valgus among valgus group subjects and thus significantly different. No differences between the groups emerged from clinical measures. No morphological pathology was detected in any knee joint. Global T2 values (42.3 ± 2.3; 37.7-47.9 ms) of ROIs placed within every knee joint per subject were not different between alignment groups or between genders, respectively. CONCLUSION: Static frontal plane leg malalignment does not affect cartilage ultrastructure among young, asymptomatic individuals as measured by T2 quantitative imaging. LEVEL OF EVIDENCE: Cross-sectional study, Level II-III.

Age does not influence the clinical outcome after high tibial osteotomy.

PURPOSE: Valgus high tibial osteotomy (HTO) is an established procedure for the medial gonarthrosis. In several studies, many negative influencing factors were evaluated. However, until now, the factor "age" was examined only insufficiently. The aim of our study was to evaluate the factor age in predicting the functional outcome after HTO, and we hypothesized that valgus HTO leads to equal results in the treatment of varus osteoarthritis independent of the patient's age. METHODS: We could generate 13 pairs of patients with a median age at operation of 57 (55-63) years (group A) versus patients 15 years younger with a median age of 42 (39-47) years (group B). The patients were matched according to the following criteria: age, gender, operation/osteosynthesis method, body mass index, same additional operations, and follow-up time. Evaluation of the patients was done by use of the Tegner and Lysholm score and visual analogue scale (VAS) as well as by subjective satisfaction of the patients. RESULTS: The Lysholm score showed a significant improvement in group A from 41 (SD ± 12.3) to 65 (SD ± 23.8) points (p = 0.01) and in group B from 33 (SD ± 16.7) to 70 (SD ± 31.8) points (p = 0.007). Moreover, the VAS decreased significantly in group A from 77 (SD ± 15.3) to 36 (SD ± 21.3) points (p = 0.003) and in group B from 73 (SD ± 22.7) to 41 (SD ± 33.7) points (p = 0.02). However, there was no significant difference for both groups regarding the activity of the patients evaluated by the Tegner score (group A: preop.: 5 (1-9), follow-up: 3.5 (1-6); group B: preop.: 6 (3-9), follow-up: 4 (2-7)). Furthermore, there was no significant difference between both groups in view of the Lysholm, Tegner and VAS. CONCLUSION: Valgus high tibial osteotomy is an effective procedure for the treatment of medial gonarthrosis independent of the patient's age. As a consequence, the age of the patient does not have to be taken into consideration for the indication of high tibial osteotomy. LEVEL OF EVIDENCE: III.

[Femoral osteotomy for patellofemoral instability]. / Femorale Osteotomien bei patellofemoraler Instabilität.

Axis and torsion malalignment of the femur has been widely recognized as a primary reason for patellofemoral instability and pain. In this article we explain the current concepts of biomechanics and describe the radiological findings in computed tomography (CT) examination. We describe the technique of a biplanar varus and/or external rotation distal femoral osteotomy in detail. Existing clinical studies describe this technique as part of a multimodal treatment concept with good to excellent results. We present our current technique and clinical results.

Donor-site morbidity after osteochondral autologous transplantation for lesions of the talus.

BACKGROUND: Autologous osteochondral transplantation is accepted as one of the major treatment options for cartilage defects of the talus. One disadvantage of this technique is the need to harvest a donor graft from a normal knee. The potentially detrimental effect of graft harvest on knee function remains unclear. METHODS: Two hundred patients who had transplantation of an autologous osteochondral graft obtained from an asymptomatic knee for the treatment of an osteochondral defect of the talus were evaluated. Of the 200 patients, 112 were followed for a minimum of two years (mean duration of follow-up, fifty-five months). The WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) and the Lysholm score were used to assess functional outcome. Variables that were examined included the number of grafts, total size of the harvested cylinders, patient age, body mass index, and overall satisfaction of the patient with the result of the procedure at the knee. A multiple linear regression analysis was utilized to determine the influence of each parameter on the WOMAC and Lysholm scores. In addition, the Lysholm scores for the entire patient group were reviewed to determine how long after the index surgery clinical improvement ceased. RESULTS: The mean postoperative WOMAC score (and standard deviation) for the 112 patients who had been followed for a minimum of two years was 5.5% +/- 0.1%, and the mean postoperative Lysholm score was 89 +/- 17 points. The number of grafts, the size of the transplanted cylinders, and patient age did not influence either the Lysholm or the WOMAC score. A higher body mass index and lower general satisfaction ratings did negatively influence the Lysholm and WOMAC scores. Gradual clinical improvement, as measured with the Lysholm score for all 200 study subjects, continued throughout the postoperative period. CONCLUSIONS: Donor-site morbidity of a knee from which a graft has been harvested can potentially lead to functional impairment. In our study, the functional outcome of the knee was not affected by the number of donor grafts, the size of the donor grafts, or the age of the patient. Surgeons performing osteochondral transplantations and harvesting autografts from the knee should be aware of the potentially negative effect of a higher body mass index on clinical outcomes after surgery.

[Analyses and comparison of 2-D vs. 3-D glenoid versions in atraumatic/traumatic shoulder instability--are 3-D analyses essential?]. / Analyse und Vergleich 2-D- vs. 3-D-Glenoidversion bei a-/traumatischer Schulterinstabilität--ist eine 3-D-Analyse notwendig?

AIM: Changes in glenoid orientation as a primary cause of shoulder instability have been discussed controversially in the literature. The data of a physiological glenoid version vary widely among different authors and techniques. One reason may be that the previously used 2-D techniques suffer from a limited reproducibility and validity. The objective of this study was therefore to compare the 2-D and 3-D analyses of the glenoid version in patients with shoulder instability. METHOD: The shoulders of 28 healthy volunteers and of 14 patients each with atraumatic/traumatic instability were examined in an open MR scanner (0.2 T). The 2-D glenoid version was determined using post-processing techniques according to the technique of Friedman et al. (1992). Afterwards, the 3-D glenoid version was analysed independently of the slice orientation and patient position. The coefficient of correlation (r) between the 2-D and 3-D glenoid versions was calculated using the correlation z test. RESULTS: The 3-D post-processing technique showed a reproducibility with a coefficient of variation of 8.3 %. Patients with traumatic instability demonstrated no significant difference compared to the healthy control group (4.4 +/- 2.1 degrees vs. healthy: 3.9 +/- 1.3 degrees). In atraumatic shoulder instability the glenoid retroversion was in the mean significantly increased (10.2 +/- 4.9 degrees). The individual values ranged between 2.6 degrees and 16.6 degrees . Also for the contralateral, unaffected side a significantly increased retroversion (6.3 +/- 2.2 degrees) was observed compared to healthy shoulders. There was a significant correlation (r: 0.84) between 2-D and 3-D retroversion. CONCLUSIONS: The presented techniques allow for a reproducible assessment of glenoid version independent of the slice orientation and patient position. Our results demonstrate in the mean only a small difference of +/- 3 degrees between 2-D and 3-D glenoid versions. Therefore under standardised conditions the 2-D CT/MRI should be adequate for measuring the glenoid version except for borderline cases. No significant changes in glenoid version were found in patients with traumatic instability. In atraumatic, posterior instability, in the mean an increased retroversion was observed on both sides. However, the magnitude of these changes varied widely among individuals and should be identified to initiate a causal treatment.

[Analyses and comparison of 2-D vs. 3-D glenoid versions in atraumatic/traumatic shoulder instability - are 3-D analyses essential?]. / Analyse und Vergleich 2-D- vs. 3-D-Glenoidversion bei a-/traumatischer Schulterinstabilität - ist eine 3-D-Analyse notwendig?

AIM: Changes in glenoid orientation as a primary cause of shoulder instability have been discussed controversially in the literature. The data of a physiological glenoid version vary widely among different authors and techniques. One reason may be that the previously used 2-D techniques suffer from a limited reproducibility and validity. The objective of this study was therefore to compare the 2-D and 3-D analyses of the glenoid version in patients with shoulder instability. METHOD: The shoulders of 28 healthy volunteers and of 14 patients each with atraumatic/traumatic instability were examined in an open MR scanner (0.2 T). The 2-D glenoid version was determined using post-processing techniques according to the technique of Friedman et al. (1992). Afterwards, the 3-D glenoid version was analysed independently of the slice orientation and patient position. The coefficient of correlation (r) between the 2-D and 3-D glenoid versions was calculated using the correlation z test. RESULTS: The 3-D post-processing technique showed a reproducibility with a coefficient of variation of 8.3 %. Patients with traumatic instability demonstrated no significant difference compared to the healthy control group (4.4 +/- 2.1 degrees vs. healthy: 3.9 +/- 1.3 degrees ). In atraumatic shoulder instability the glenoid retroversion was in the mean significantly increased (10.2 +/- 4.9 degrees ). The individual values ranged between 2.6 degrees and 16.6 degrees . Also for the contralateral, unaffected side a significantly increased retroversion (6.3 +/- 2.2 degrees ) was observed compared to healthy shoulders. There was a significant correlation (r: 0.84) between 2-D and 3-D retroversion. CONCLUSIONS: The presented techniques allow for a reproducible assessment of glenoid version independent of the slice orientation and patient position. Our results demonstrate in the mean only a small difference of +/- 3 degrees between 2-D and 3-D glenoid versions. Therefore under standardised conditions the 2-D CT/MRI should be adequate for measuring the glenoid version except for borderline cases. No significant changes in glenoid version were found in patients with traumatic instability. In atraumatic, posterior instability, in the mean an increased retroversion was observed on both sides. However, the magnitude of these changes varied widely among individuals and should be identified to initiate a causal treatment.

[Winter sports and shoulder arthroplasty]. / Schulterprothese und Wintersportfähigkeit.

Nowadays, a general negative evaluation of sportive activity regarding different kinds of sport following arthroplasty is at present no more scientifically supported. However, at present no valid guidelines regarding sportive activity of patients after implantation of shoulder joint arthroplasty exist. The question regarding the ability of performing winter sports activities of patients treated with shoulder joint endoprothesis has not been answered so far. Therefore the aim of the presented work was to identify winter sports-specific risks for patients treated with shoulder joint endoprothesis as well as to critically discuss the actual literature in refer to winter sport activities. Criteria for the education of patients with shoulder joint endoprothesis as well as consultation regarding winter sport activities will be provided for the orthopaedic surgeon.

[Infection after arthroscopy]. / Infektion nach Arthroskopie.

Infection of a peripheral joint following arthroscopic surgery is extremely rare, with an incidence of up to 0.42%. However, the consequences of delayed diagnosis can be dramatic. Besides taking an exact patient history, C-reactive protein determination and, especially, diagnostic arthrocentesis are required. For early-stage infections, arthroscopic therapy has been proven valuable. In addition, calculated and antibiogram-adjusted antibiotic therapy is essential. In the case of persisting signs of infection, re-arthroscopy should be considered quickly, with indications broad. The number of necessary revisions depends on the initial stage of infection. Postoperative immobilisation of the affected joint is occasionally essential for treating pain; otherwise, early mobilisation of the joint should be performed.

The effect of closed- and open-wedge high tibial osteotomy on tibial slope: a retrospective radiological review of 120 cases.

Radiographs of 110 patients who had undergone 120 high tibial osteotomies (60 closed-wedge, 60 open-wedge) were assessed for posterior tibial slope before and after operation, and before removal of the hardware. In the closed-wedge group the mean slope was 5.7 degrees (SD 3.8) before and 2.4 degrees (SD 3.9) immediately after operation, and 2.4 degrees (SD 3.4) before removal of the hardware. In the open-wedge group, these values were 5.0 degrees (SD 3.7), 7.7 degrees (SD 4.3) and 8.1 degrees (SD 3.9) respectively, when stabilised with a non-locking plate, and 7.7 degrees (SD 3.5), 9.4 degrees (SD 4.1) and 9.1 degrees (SD 3.8), when stabilised with a locking plate. The reduction in slope (-2.7 degrees (SD 4.1)) in the closed-wedge group and the increase (+2.5 degrees (SD 3.4), in the open-wedge group was significantly different before and after operation (p = 0.002, p = 0.003). In no group were the changes in slope directly after operation and before removal of the hardware significant (p > 0.05). There was no correlation between the amount of correction in the frontal plane and the post-operative change in slope. Posterior tibial slope decreases after closed-wedge high tibial osteotomy and increases after an open-wedge procedure because of the geometry of the proximal tibia. The changes in the slope are stable over time, emphasising the influence of the operative procedure rather than of the implant.

[Musculoskeletal biomechanics of the knee joint. Principles of preoperative planning for osteotomy and joint replacement]. / Muskuloskelettale Biomechanik des Kniegelenks. Grundlagen für die präoperative Planung von Umstellung und Gelenkersatz.

The long-term clinical outcome of surgical interventions at the knee is dependent upon the quality of the restoration of normal function, together with moderate musculoskeletal loading conditions. In order to achieve this, it is essential to consider biomechanical knowledge during the planning and execution of the procedures. Until now, such knowledge has only been available in books and journal manuscripts and is merely considered during preoperative planning. Its transfer into the specific intraoperative situation is, however, primarily dependent upon the surgeon's skills and understanding. Mathematical models hold the potential to provide the surgeon with detailed, patient-specific information on the in vivo forces, as well as their spatial and temporal distribution. Their application in clinical routine, however, requires a comprehensive validation. Based on a model validated against patient data, it has been shown that - mainly as a result of the action of the muscles - both the tibiofemoral as well as the patellofemoral joints experience substantial mechanical loads even during normal activities of daily living. The calculations further indicate that malalignment at the knee in the frontal plane of more than approximately 4 degrees results in considerably increased forces across the tibiofemoral joint. The actual change in force to a given degree of malalignment might, however, vary greatly between subjects. In order to additionally determine the distribution of the forces in more detail, a sufficiently accurate model of knee joint kinematics is required. In combination with MR-based in vivo imaging techniques, new mathematical models offer the possibility to capture the individual characteristics of knee kinematics and might additionally allow the effect of muscle activity on joint kinematics to be considered. By implementing these technologies in preoperative planning and navigation systems, up-to-date biomechanical knowledge can be made available at the surgeons' fingertips. We propose that optimizing the biomechanical conditions through using these approaches will allow the long-term function of the replaced joint to be significantly enhanced.

Operative treatment of greater tuberosity fractures of the humerus--a biomechanical analysis.

BACKGROUND: Fractures of the greater tuberosity of the humerus present with increasing frequency. However, no biomechanical data about the optimal fixation technique of greater tuberosity fractures is available. This biomechanical cadaver study compares the stability of three standard fixation techniques used for the treatment of greater tuberosity fractures of the proximal humerus. METHODS: In 21 fresh frozen proximal humeri, standardized fractures of the greater tuberosity were created. The specimens were randomly assigned to one of three operation techniques: wire tension banding, two cancellous screws and transosseous sutures. These constructs were mechanically tested by applying an increasing force to the supraspinatus tendon. Load to 5mm displacement (load to 5mm yield point) and load to failure (maximum stretch strength) were measured in Newton (N). FINDINGS: Load to 5mm yield point values showed no significant differences between tension banding (498 N, SD 153) and two cancellous screws (400 N, SD 174) (P>0.01). Both techniques showed significantly higher values than transosseous sutures (185 N, SD 132) (P<0.01). Load to failure values were significantly higher for tension banding (1054 N, SD 125) than screws (842 N, SD 140) and sutures (480 N SD 101) (P<0.01). The difference between screws and sutures was also significant (P<0.01). INTERPRETATION: Tension banding and two cancellous screws provided the strongest fixation for isolated fractures of the greater tuberosity.

A new model to predict in vivo human knee kinematics under physiological-like muscle activation.

Although a number of approaches have attempted to model knee kinematics, rarely have they been validated against in vivo data in a larger subject cohort. Here, we assess the feasibility of four-bar linkage mechanisms in addressing knee kinematics and propose a new approach that is capable of accounting for lengthening characteristics of the ligaments, including possible laxity, as well as the internal/external rotation of the joint. MR scans of the knee joints of 12 healthy volunteers were taken at flexion angles of 0 degrees , 30 degrees and 90 degrees under both passive and active muscle conditions. By reconstructing the surfaces at each position, the accuracy of the four-bar linkage mechanism was assessed for every possible combination of points within each cruciate ligament attachment area. The specific set of parameters that minimized the deviation between the predictions and the in vivo pose was derived, producing a mean error of 1.8 and 2.5 on the medial and 1.7 and 2.4mm on the lateral side at 30 degrees and 90 degrees flexion, respectively, for passive motion, significantly improving on the models that did not consider internal/external rotation. For active flexion, mean medial errors were 3.3 and 4.7 mm and lateral errors 3.4 and 4.8 mm. Using this best parameter set, a generic predictive model was created and assessed against the known in vivo positions, producing a maximum average error of 4.9 mm at 90 degrees flexion. The accuracy achieved shows that kinematics may be accurately reconstructed for subject specific musculoskeletal models to allow a better understanding of the load distribution within the knee.