Influence of preoperative factors on the gain in flexion after total knee arthroplasty.

UNLABELLED: Final flexion mobility after a total knee arthroplasty is an important factor in patient comfort. Some patients gain in flexion mobility, others do not. Is it possible to identify the clinical factors related to the patient that predicted the final gain in flexion? MATERIALS AND METHODS: A multicenter retrospective study directed by the Société française de la hanche et du genou (SFHG) was conducted on 1601 cases of total knee arthroplasty that had presented no complications and a minimal follow-up of 2 years. The gain in flexion was assessed by the difference between the preoperative and the final range of flexion. The range of the gain in flexion was tested based on eight factors: age, gender, etiology, body mass index, frontal deformity, preoperative flexum deformity and four levels of preoperative mobility: < 90°, 90°-109°, 110°-129°, and ≥ 130°. RESULTS: A mean gain in flexion of 8.4°±14° was found for the overall series. In 66% of cases, we found an increase of flexion and in 19% a loss of flexion. In cases with BMI higher than 35, varus deformity with an HKA angle<166°, or flessum greater than 5°, the gain in flexion was significantly higher. A significantly different gain in flexion (P<0.0001) was found in the four levels of preoperative flexion: the greatest gain in flexion was found in the "<90°" group, then this gain was less in the next two groups, to become a significant decrease in the "≥130°" group. A decrease in flexion was noted in 51% of the cases in the latter group. Other factors such as age, sex, and etiology had no influence on the gain in flexion. DISCUSSION: After TKA, a gain in flexion was often noted. The amount of gain depended on the preoperative range of flexion: the lower this level was, the more flexion increased. The presence of a varus deformity, morbid obesity, or flessum was associated with greater gain in flexion, even if the final flexion was lower than the mean flexion in the overall population. The search for these factors made it possible to predict a gain in flexion and discuss this with the patient. LEVEL OF EVIDENCE: Level IV. Multicenter retrospective study.

Results of surgical treatment of calcaneus insertional tendinopathy in middle- and long-distance runners.

PURPOSE: Calcaneus insertional tendinopathy in runners is common and involves important therapeutic controversies. The object of this study was to determine the delay and level of return to sport after insertional surgery in runners, with and without tendon damage. METHODS: Eighteen runners underwent surgery for insertional calcaneus tendinopathy. Nine required an exostosectomy/bursectomy, and nine others required a tendon reinsertion/autograft. All patients were clinically assessed pre- and post-operatively with AOFAS scores and post-operatively with ATRS. This series included analysis of "pure conflicts" and "severe insertional lesion" scores. If the insertional tendon was free or the lesion was smaller than 50 %, the group was classified as "pure conflict/minor tendon damage". In the situation in which a loss of tendon occurred or the tendon lesion was greater than 50 %, the group was classified as "major tendon damage". Pre-operatively, the AOFAS "overall", "pure conflicts/minor tendon damage" and "major tendon damage" groups' scores were 58.5 ± 15, 68.2 ± 8.8 and 48.9 ± 13.9/100, respectively. RESULTS: Post-operatively, the AOFAS "overall", "pure conflicts/minor tendon" and "major tendon damage" groups' scores were 93.7 ± 8.2, 93.2 ± 10.2 and 95.2 ± 5.7/100, respectively. The AOFAS score gain for each group was, respectively, 35.2 ± 19, 24 ± 17 and 46.3 ± 14.1. The ATRS "overall", "pure conflicts/minor tendon damage" and "major tendon damage" groups' scores were 81.5 ± 14.9, 78.3 ± 20.1 and 84.7 ± 6.7/100, respectively. The global sport recovery delay was 9.3 ± 4.1 months; it was 6 ± 3.3 months for the pure conflict/minor tendon damage subgroup and 10 ± 4.6 months for the severe tendon damages subgroup. CONCLUSION: Achilles insertional tendinopathy surgery on this population results in few complications with good functional results if the surgical technique is adapted to the type of tendon injury. The clinical relevance of this study is that it highlights the various forms of calcaneus insertional tendinopathy and various treatment options. The authors show that in the case of major tendon damage, time to return to sport is longer.

Treatment of chronic Achilles tendon rupture by shortening suture and free sural triceps aponeurosis graft.

INTRODUCTION: The Bosworth technique is old but still widely used. It involves problems of precisely determining the length of the Achilles tendon and of a volume effect in the turndown area. HYPOTHESIS: A new reconstruction technique is assessed, based on free sural triceps aponeurosis transfer without turndown, associated to tendon shortening suture. MATERIALS AND METHODS: Twenty-three patients were assessed by AOFAS score and clinical examination (plus MRI in 14 cases) at a mean 24.5 months' follow-up. Mean age was 52.1 years. Mean pre-operative AOFAS score was 63.6/100. RESULTS: Mean postoperative AOFAS score was 96.1. Mean graft length was 7.5 cm. Surgical revision was required for one case of postoperative infection. Twelve patients resumed leisure sports at their previous level by a mean 9.4 ± 2 months; three competitive sportsmen resumed sport at their previous level by a mean 7.6 months. None were dissatisfied or disappointed with their operation. MRI performed at 1 year found increased tendon volume without abnormality in 57% of cases; 43% showed abnormal images. DISCUSSION: Functional results were comparable to literature reports. It can be difficult to determine Achilles length for the Bosworth technique: this is made easier by conserving a fibrous support of a length determined with reference to the healthy side. The technique avoids aponeurosis turndown, and thus avoids the problem of plasty volume effect. The two cases of cutaneous complication occurred in the two most elderly patients, raising the question of the indications for reconstructive surgery in the elderly. The abnormalities found on MRI concerned scar tissue remodeling in patients with good or excellent clinical results. LEVEL OF EVIDENCE: Level IV, retrospective study.

Measuring femoral and rotational alignment: EOS system versus computed tomography.

INTRODUCTION: Computed tomography (CT) is currently the reference standard for measuring femoral and tibial rotational alignment. The EOS System is a new biplanar low-dose radiographic device that allows 3-dimensional lower-limb modelling with automated measurements of femoral and tibial rotational alignment (torsion). HYPOTHESIS: Femoral and tibial torsion measurements provided by the EOS System are equivalent to those obtained using CT. MATERIALS AND METHODS: In a retrospective analysis of 43 lower limbs in 30 patients, three senior radiologists measured femoral and tibial torsion on both CT and EOS images. Agreement between CT and EOS values was assessed by computing Pearson's correlation coefficient and interobserver reproducibility by computing the intraclass correlation coefficient (ICC). RESULTS: Femoral torsion was 13.4° by EOS vs. 13.7° by CT (P=0.5) and tibial torsion was 30.8° by EOS vs. 30.3° by CT (P=0.4). Strong associations were found between EOS and CT values for both femoral torsion (P=0.93) and tibial torsion (P=0.89). With EOS, the ICC was 0.93 for femoral torsion and 0.86 for tibial torsion; corresponding values with CT were 0.90 and 0.92. DISCUSSION: The EOS system is a valid alternative to CT for lower-limb torsion measurement. EOS imaging allows a comprehensive evaluation in all three planes while substantially decreasing patient radiation exposure. LEVEL OF EVIDENCE: Level III, case-control.

Unstable odontoid fracture: surgical strategy in a 22-case series, and literature review.

Surgical treatment of unstable odontoid fracture (type II OBAR or HTAL) has progressed, with a range of techniques, the specificities of which need to be known so as to determine their respective roles in the therapeutic arsenal now available. A retrospective study of 22 patients operated on in our center for odontoid fracture between 2005 and 2010 examined the operative techniques employed and analyzed results in the light of the literature, so as to construct an updated decision tree. Two populations could be distinguished: elderly victims of simple fall (mean age, 82.1 years), and younger victims of high-energy trauma (mean age, 42.6 years). Surgical techniques comprised: anterior odontoid screwing (n=14), transarticular C1-C2 screwing on the posterior Magerl (n=3) or anterior Vaccaro approach (n=1), Harms' posterior C1-C2 arthrodesis (n=3), and occipitocervical arthrodesis (n=3). The overall complications rate for the series was 28%, including one case of non-union, at a mean 11 months' follow-up. The risk/benefit ratio may be hard to assess in elderly patients. However, anterior screwing restores odontoid anatomy and is the technique of choice in first intention for reducible fracture. In second intention, transarticular C1-C2arthrodesis may be performed on an anterior or posterior approach, depending on local vertebral artery anatomy. Harms' posterior C1-C2 arthrodesis allows fixation of non-reduced fractures. Occipitocervical arthrodesis is a last resort, as the associated morbidity rate is higher.

Anterior cruciate ligament reconstruction with fascia lata using a minimally invasive arthroscopic harvesting technique.

Anterior cruciate ligament (ACL) reconstruction using the fascia lata has undergone a number of technical modifications since the work of Hey-Groves, MacIntosh, and Jaeger. Arthroscopy has simplified this technique, notably in the positioning of the tunnels. Minimally invasive harvesting through two lateral proximal and distal approaches considerably reduces cosmetic problems. The femoral tunnel is made from the outside to the inside using a specific targeting device, and the transplant harvest site is closed using the Jaeger procedure so as not to weaken lateral knee stabilizing structures. This procedure consists in opening the lateral intermuscular septum 1cm from the femur to let it shift laterally and allow the transplant harvesting area to be closed. This technique uses a fascia lata transplant, the harvesting of which has shown few iatrogenous complications but requires rigorous adherence to certain rules.

Patellar height modification after high tibial osteotomy by either medial opening-wedge or lateral closing-wedge osteotomies.

PURPOSE: High valgus tibial osteotomy is used to treat medial femoro-tibial osteoarthritis. Changes in patellar height due to high valgus tibial osteotomy can cause technical difficulties during subsequent knee arthroplasty. The primary objective of this study was to assess the hypothesis that patellar height decreases after opening-wedge osteotomy and increases after closing-wedge osteotomy. The secondary objective was to assess whether frontal axis correction and tibial slope modification correlated with patellar height changes. METHODS: A multicentre, prospective, comparative, observational, non-randomised study was conducted in consecutive patients undergoing isolated high valgus tibial osteotomy according to standard practice in each of the ten study centres. Patellar height was assessed based on the Caton-Deschamps index. RESULTS: Of 321 included patients, 224 underwent opening-wedge and 97 closing-wedge osteotomy. Patellar height did not change significantly after closing-wedge osteotomy (1.07 ± 0.2 pre-operatively and 1.0 ± 0.19 postoperatively). Patellar height decreased significantly after opening-wedge osteotomy (from 0.98 ± 0.19 to 0.88 ± 0.21, p < 0.0001, mean decrease 9 ± 22%). Patellar height decreased by more than 20% in 49 (28%) patients after opening-wedge osteotomy. The patellar height decrease after opening-wedge osteotomy correlated significantly with axis correction magnitude and tibial slope change. CONCLUSION: Our results support routine baseline measurement of patellar height before high valgus tibial osteotomy and posterior positioning of the opening wedge to limit the tibial slope change in patients requiring major axis correction by opening-wedge osteotomy. LEVEL OF EVIDENCE: Prospective cohort study, Level II.

Accuracy of the preoperative planning for cementless total hip arthroplasty. A randomised comparison between three-dimensional computerised planning and conventional templating.

INTRODUCTION: A high accuracy was recently reported for the three-dimensional (3D) computerised planning of total hip arthroplasty (THA), comparing well with navigation regarding leg length and femoral offset. However, there is no randomised study comparing 3D preoperative planning with conventional 2D templating in terms of accuracy and clinical relevance. HYPOTHESIS: The 3D preoperative planning has a higher accuracy than the conventional 2D preoperative templating regarding the implants size and their positioning. PATIENTS AND METHODS: A prospective comparative randomised study was carried out from 2008 to 2009, including two groups of 30 patients who underwent THA for primary osteoarthritis. One surgeon performed all the surgical procedures using a minimally invasive direct anterior approach. In one group, the planning was made on calibrated X-rays using 2D templates. In the other group, a CT-scan based 3D computerised planning was performed with dedicated software. The reconstructed hip final anatomy was compared postoperatively to the preoperative planning and the accuracy was expressed as the mean difference (±SD) between the planned positioning and the final positioning of the implants. RESULTS: The prediction rate for the stem and the cup sizes were respectively of 100% and 96% in the 3D group versus 43% for both components in the 2D group. When combining both components, the prediction rate was 96% in the 3D group versus 16% in the 2D group. In the 3D group, a high accuracy was achieved for the planning of the leg length (-1.8±3.6 mm ranging from -8 to+4mm) and the femoral offset (-0.07±2.7 mm ranging from -5 to+4mm) versus 1.37±6.4mm ranging from -9 to 13 mm and 0.33±5.7 mm (-16 to 11 mm) in the 2D templating group (P<0.0001). DISCUSSION: The 3D planning gives a higher accuracy than conventional 2D templating in forecasting the size of cup and the stem. This contributes to the prediction for leg length and offset that is more reliable with the 3D technique. This study suggests that 3D planning CT-scan data is an attractive alternative to navigation to restore these parameters. The high accuracy achieved by a low-experience surgeon suggests that 3D planning may help shorten the learning curve when using the minimally invasive direct anterior approach. LEVEL OF EVIDENCE: Level III low-powered prospective randomized trial.

Distal partial ruptures of triceps brachii tendon in an athlete.

Distal brachii triceps tendon rupture is rare. Partial lesions are not so well defined. If functionally they are well tolerated in patients with low functional demand, management guideline is not so clear for sportsmen. To our best knowledge, there is no reported technique for the repair of partial forms. A 28-year-old patient was operated on for a partial triceps rupture. He underwent a transosseous olecranon suture of the tricipital tendon, with a side-to-side suture to the healthy residual tendon. The patient was assessed at 2 years follow-up with the DASH score. He had painless and mobile elbow with no effusion and returned to sport 4 months after his surgical repair. The extension strength was comparable to the healthy side (5/5). The DASH score was 1,7 for global score, and 6,3 for work and sport modules. Partial rupture of brachii triceps tendon is not well tolerated in high functional demand patients. We think that patients should be operated in these situations and may achieve excellent results. Postoperative management is crucial to achieve good results as well as in complete rupture.

Posterior tibial slope changes after opening- and closing-wedge high tibial osteotomy: a comparative prospective multicenter study.

INTRODUCTION: Valgus high tibial osteotomy is considered to be an effective treatment for unicompartmental medial osteoarthritis. It is generally admitted that tibial slope increases after open-wedge high tibial osteotomy and decreases after closing-wedge high tibial osteotomy. However, the effects on posterior tibial slope of closing- or opening-wedge osteotomies remain controversial. HYPOTHESIS: We analyzed the modifications of tibial slope after opening- and closing-wedge high tibial osteotomies and compared the results of these two procedures. We hypothesized that there was no difference in postoperative tibial slope between opening and closing-wedge osteotomies. PATIENTS AND METHODS: This prospective consecutive nonrandomized multicenter study was conducted between January 2008 and March 2009 and included 321 patients: 205 men and 116 women. A total of 224 patients underwent an opening-wedge high tibial osteotomy and 97 a closing-wedge osteotomy. The mean age was 52 years ± 9 and the mean body mass index was 28kg/m(2) ± 5. The main etiology was primary arthritis. Posterior tibial slope was measured preoperatively and at the last follow-up on a lateral radiograph in relation to the posterior tibial cortex. RESULTS: In the opening-wedge group, a definite 0.6° increase in tibial slope (P=0.016) was observed. In the closing-wedge group, a definite 0.7° decrease in tibial slope (P=0.02) was found. Fourteen percent of the opening-wedge osteotomies increased tibial slope by 5° or more versus only 2% of the closed-wedge osteotomies (P<0.001). Twelve percent of the closing-wedge high tibial osteotomies led to a decrease of 5° or more of the tibial slope versus 7% of the opening-wedge osteotomies (P<0.02). DISCUSSION AND CONCLUSION: These results confirm what is generally reported in the literature, i.e., an increase in tibial slope in opening-wedge high tibial osteotomy and a decrease in the slope in closing-wedge osteotomies. These tibial slope changes appear to be very limited in this series, less than 1° on average. However, there was a bias since the open-wedge technique was preferred in cases with substantial varus deformity. We emphasize the importance of surgical technique to avoid alteration of the tibial slope, particularly in opening-wedge high tibial osteotomy for which we recommend a release of posterior soft tissue and a complete osteotomy of the posterior cortex of the tibia. LEVEL OF EVIDENCE: III. Prospective consecutive nonrandomized multicenter study.

Pelvis and total hip arthroplasty acetabular component orientations in sitting and standing positions: measurements reproductibility with EOS imaging system versus conventional radiographies.

INTRODUCTION: The literature has recently underlined the interest of pelvic and acetabular component orientation measurements in the standing and sitting position. Radiographic follow-up of total hip arthroplasty (THA) is based on standard AP and lateral X-rays. The use of EOS™ 2D imaging system reduces patient's radiation exposure compared to conventional X-rays. However, using this system, the validity and reproducibility of angular measurements, have not been studied yet for the measurement of pelvic and acetabular parameters in patients with THA. HYPOTHESIS: The EOS™ 2D imaging system offers similar advantages to conventional X-rays in the measurement of pelvic and acetabular orientation parameters which are commonly used. PATIENTS AND METHOD: Five angular parameters characterizing pelvic tilt and acetabular cup orientation were determined using the same digital measurement Imagika™ software based on two series of standard X-rays and EOS™ 2D images acquired in both standing and sitting positions. Radiographs from 50 patients with unilateral THA were measured three times by two observers. Intra- and interobserver reproducibility using each method was independently studied then paired comparison was performed. RESULTS: The ICC and Spearman rank correlation coefficient demonstrated an excellent EOS/conventional X-ray correlation. According to the parameters, the mean difference between these two imaging modalities ranged from 0.30° to 3.43° (P<0.05). The intra- and interobserver variability ranged from ± 2.97° to ± 6.46° using the EOS™ imaging system and from ± 4.26° to ± 10.22° using conventional X-rays (P<0.05). DISCUSSION: The EOS™ 2D imaging system may replace conventional X-rays in the assessment and monitoring of pelvic and acetabular cup orientation in THA. LEVEL OF EVIDENCE: Level III. Prospective diagnostic study.

The EOS imaging system for understanding a patellofemoral disorder following THR.

An aspect of patellofemoral syndrome secondary to total hip replacement (THR) is mainly suggestive of a problem of femoral implant torsion. We here present the first reported case of patellofemoral syndrome secondary to THR relating to limb-length discrepancy, with no abnormality of femoral torsion. The pelvis adapted to the length inequality by axial rotation rather than frontal tilt, and this went undetected on standard X-ray and CT-scan. 3D imaging in upright posture on the EOS system enabled the situation to be clearly described and analyzed, and adapted surgical correction to be indicated.

Post-traumatic knee osteoarthritis treated by osteotomy only.

BACKGROUND: Osteotomies to address lower extremity post-traumatic deformities are more complex than standard osteotomies performed for congenital deformities, standard osteotomies and their outcomes are not well known. We performed a multicentric retrospective study of these cases. We hypothesized that osteotomy without total knee replacement to correct fracture malunion deformities can provide long-term relief from athritic pain. PATIENTS AND METHODS: Twenty-eight patients, mean age 46.4 years old, underwent, between 2000 and 2008, osteotomy for post traumatic osteoarthritis which had resulted in intraarticular malunion in six patients and extraarticular malunion in 22 cases. The initial trauma had occurred a mean 17.3 years before. There were 11 valgus and 17 varus deformities. Two osteotomies were performed in the callus to correct intraarticular malunion. The other osteotomies were performed outside the callus: in 25 cases to correct coronal plane deformities (nine tibial, 11 femoral and five tibial and femoral), including nine cases with associated derotation. Osteotomies were performed on the distal femoral metaphysis and the proximal tibia. There was also one case of supramalleolar derotation osteotomy of the tibia. All 28 patients were contacted again for a consultation. There was a postoperative clinical and radiographic follow-up of at least 2years for all patients despite four lost to follow-up patients. There were 18 patients with Ahlback grade 2 arthritis, nine grade 3 and one grade 4. RESULTS: Two patients with an intraarticular malunion finally underwent revision surgery to receive total knee replacement because of persistent pain. These patients had grade 3 and 4 arthritis respectively and undercorrection persisted in the coronal plane. Four patients underwent repeated surgery for stiffness, early infection treated with debridement and antibiotics as well as femoral pseudarthrosis (two cases). After a mean follow-up of 3.8 years, the pain score had improved significantly with more marked improvement in extraarticular malunions (P=0.03). Functional improvement was moderate (equivalent in patients with Ahlback grades 2 and 3 arthritis) and articular range of motion did not change. Osteotomy corrected valgus and varus deformities with a mean realignment effect of 9° and 10° respectively. DISCUSSION: Osteotomy should correct the three components of the traumatic deformity at the distal femoral metaphysic level to allow mechanical axis and rotation anomalies correction, and at the proximal tibia level for realignment purposes. Supramalleolar tibial osteotomy should be performed for tibial derotation. Pain relief with osteotomy had better outcomes when dealing with extraarticular malunions. In unicompartmental grade 2 and 3 arthritis, the indications can be fairly broad in young patients. Besides providing temporary relief, osteotomy facilitates future total knee replacement surgery in these cases. LEVEL OF EVIDENCE: Level 4; non controlled, retrospective study.

Total knee arthroplasty for osteoarthritis secondary to extra-articular malunions.

INTRODUCTION: Post-traumatic total knee arthroplasty for extra-articular malunion requires correction of the deformity, either through asymmetrical bone resection (possibly inducing ligaments imbalance) or osteotomy at the time of arthroplasty. We report the results of a continuous multicenter, retrospective series of 78 patients (18 implants with osteotomy) with a mean 4 years of follow-up. The hypothesis is that the selected procedure requires to be based on the deformity's location and severity. PATIENTS: With a mean age of 63 years (younger in the osteotomy group), 38 patients had femoral malunion, 36 had tibial malunion, and four had a combined malunion. There were 70 frontal deformities (48 varus and 22 valgus) and 10 rotational deformities, often diaphyseal, four of which more than 20°. Twelve patients had a history of infection; eight had frontal laxity greater than 10°, and 15 a limited range of motion in flexion. In 70 cases, semi- or nonconstrained implants were used, and in eight cases more constrained implants, including four hinge prostheses. RESULTS: We observed two deep infections, one case of avulsion of the extensor mechanism, and two cases of aseptic loosening with femoral malunion and varus deformity. Two osteotomies resulted in nonunion, one with internal fixation devices mobilization requiring revision using extension rods. The function and pain scores were significantly improved. The mobility improvements were moderate but did not compromise the surgical procedure main objective. The preoperative hip-knee angle was corrected with both techniques. Only the function score gain was greater for the isolated arthroplasty procedures. DISCUSSION AND CONCLUSION: The indications for arthroplasty alone were extended to 20° varus and 15° valgus, with no major residual laxity. Beyond 10°, hinge prosthesis should be available. Associated osteotomy can correct rotational deformities that cannot be compensated with bone cuts. In deformities that are close to the joint, osteotomy facilitates implantation of moderately constrained prosthesis. This indication is based on CAT scan rotational deformities measurements because rotational deformities require an osteotomy, and/or the presence of extraligamentous deformity that cannot be reduced with collateral ligaments surgical release. LEVEL OF EVIDENCE: Level 4. Non-controlled retrospective study.

Pneumorachis: a possible source of traumatic cord compression.

The presence of air within the spinal canal secondary to trauma is a rare condition. These rare cases are generally asymptomatic. We report our first case of closed thoracic trauma with pneumorachis associated with neurological disorders. According to a review of the literature and after personal record analysis, neurologic symptoms can be correlated to the occurrence of intraspinal air. Therefore pneumorachis appears as a possible cause of traumatic spinal cord compression. In this particular case, pneumorachis spontaneously resolved and early outcome was favourable.

Iliac crest bone graft harvesting complications: A case of liver herniation.

The iliac crest is an easily accessible donor site offering a relatively large and safe supply of bone. There are however possible complications; residual pain frequently, and more rarely herniation. This latter's true incidence is unknown in a literature review, which found 15 articles. We report a case of liver herniation in a 64-year-old overweight lady after harvesting bone from her iliac crest. The clinical diagnosis was confirmed by CT scan. Despite an appropriate surgical repair, the hernia recurred. This serious complication of bone harvesting from the iliac crest, and possible other undesirable events described, prompted reconsideration of our harvesting techniques, and the use in our unit of bone substitutes or cell therapy to fill bone defects.

Skeletal landmarks for TKR implantations: evaluation of their accuracy using EOS imaging acquisition system.

INTRODUCTION: Lower extremity alignment remains one essential objective during total knee replacement. Implants positioning analysis requires selecting reliable skeletal landmarks. Our objective was to in vivo evaluate the precision of the implemented skeletal landmarks. This evaluation was based on multiple three-dimensional (3D) computer reconstructions of the lower extremity derived from an EOS biplanar low-dose X-ray system acquisition. A 3D angle measurement protocol was used. HYPOTHESIS: Currently defined landmarks carry a tolerable uncertainty margin, which can still probably be further improved. MATERIAL AND METHODS: Nine lower extremity 3D computer reconstructions were obtained from an EOS protocol based on seven simultaneous A-P and lateral views performed in standing position. A database was established by four operators; finally, building up a total of 99 in vivo 3D reconstructions of these nine lower extremities. Specific algorithms were used for such 3D reconstructions of lower extremities based on bone points and pre-identified contours on X-ray. Four femoral landmarks and four tibial landmarks were thus defined. For each bone and each landmark studied, a mean landmark for the 11 consecutive series elements was established. The deviation from each constructed landmark to the corresponding mean landmark was calculated based on the anteroposterior (x), longitudinal (y) and mediolateral axes (z), in translation (Tx, Ty, Tz) and in rotation (Rx, Ry, Rz). Uncertainty was estimated by the 95% confidence interval (95% CI). RESULTS: The landmarks located at the middle of the segment joining the center of each posterior condyle and at the barycenter of the plateaux showed a greater reliability; these landmarks uncertainty (95% CI) of Tx, Ty, Tz was less than 1, 0.5, 1.5 mm for the femur and 1.5, 0.6, 0.6 mm for the tibia, respectively. The femoral landmarks using the center or posterior edge of the posterior condyles to define the mediolateral axis were retained; for rotations Rx, Ry, and Rz, uncertainty remained less than 0.3, 4, and 0.5 degrees. All of the tibial landmarks had a comparable reliability in rotation, 95% of the Rx and Rz deviations were under 0.5 and 1.3 degrees, respectively, with a mean error less than 1 degrees . For the tibial rotation Ry, the mean error was greater (4 degrees), with uncertainty (95% CI) at 11.2 degrees. All tibial translations showed a mean error of 1 mm. The 3D implantation angles were measured on two patients using preoperative 3D skeletal reconstructions and 3D geometric models of the implants repositioned on postoperative EOS knee X-rays. DISCUSSION: The posterior condyles are rarely involved in the arthritic wear process, making them an anatomic landmark of choice in the analysis of the femoral component positioning. The femoral landmarks using the posterior condyles were sufficiently reliable for clinical use. However, the posterior contours of the tibial plateaux were less precise. The knees should be staggered from an anteroposterior perspective on the EOS lateral images so that they can be visualized separately. The anatomic zones on which the skeletal landmarks are based are usually removed by the bone cuts, making it preferable to save the preoperative computer reconstructions to analyze the postimplantation 3D reconstruction. CONCLUSION: The lower extremity skeletal landmarks precision relates to the quality of the corresponding 3D reconstructions. Except for tibial rotation, all the translation and rotation parameters were estimated within a mean error margin inferior to 1.2 mm and 1.3 degrees, respectively. Making the reconstruction algorithms more robust would render certain anatomic zones even more precise. Biplanar low-dose EOS X-ray system is a tool of the future to generate 3D knee X-rays that can improve the evaluation and follow-up of total knee arthroplasty patients.

Modification of tibial slope after medial opening wedge high tibial osteotomy: clinical study and mathematical modelling.

A prospective non-randomized non-comparative study involved 30 patients who underwent a medial opening wedge high tibial osteotomy for medial knee osteoarthritis using a specific surgical procedure. The tibial slope was calculated pre-operatively and at a mean follow-up of 14 months. A mathematical model of the surgical procedure was developed in order to plan the height of the medial opening wedge and to predict tibial slope changes. Tibial-slope measurements accuracy was good (0.04 degrees +/- 0.92 degrees ). There was no significant difference for the mean tibial slope before and after surgery (9.2 degrees +/- 5.6 degrees vs. 9.1 degrees +/- 5.6 degrees , P = 0.47). There was a perfect agreement between the model and the real values for the HKA angle (0.85) and the tibial slope (0.98). The surgical technique used did not modify the tibial slope. Our mathematical model for pre-operative planning was validated with very good accuracy.

Clinical, radiological and histological evaluation of biphasic calcium phosphate bioceramic wedges filling medial high tibial valgisation osteotomies.

We report clinical, radiological and histological findings following high tibial valgisation osteotomy (HTVO) using micro-macroporous biphasic calcium phosphate wedges fixed with a plate and locking screws. From 1999 to 2002, 43 knees were operated on and studied prospectively. All underwent clinical and radiological follow-up at days 1, 90, and 365 to evaluate consolidation and bone substitute interfaces. Additionally, biopsies were taken for histology at least 1 year after implantation from 10 patients who requested plate removal. Radiologically, consolidation was observed in 98% of cases. At 1 year, correction was unchanged in 95% of cases. Histological analysis revealed considerable MBCP resorption and bone ingrowth, both into the pores and replacing the bioceramic material. Polarised light microscopy confirmed normal bony architecture with trabecular and/or dense lamellar bone growth at the expense of the wedge implants. X-ray and micro-CT scan revealed a well organised and mineralised structure in the newly-formed bone. This study shows that using MBCP wedges in combination with orientable locking screws and a plate is a simple, safe and fast surgical technique for HTVO. The is the first study to examine the results by histological analysis, which confirmed good outcomes.

Fractures of the lateral process of the talus. Retrospective study of 44 cases.

PURPOSE OF THE STUDY: Fractures of the lateral process of the talus often go undiagnosed. The cohorts reported in the literature are small. The aim of the study was to analyze these fractures with a large group of patients. MATERIALS AND METHODS: Forty-four fractures in 43 patients were reviewed with a mean follow-up of 17 months. The diagnosis had been made immediately in 14 cases and secondarily in 30 cases with a delay of 46 months. Patients were evaluated with Kitaoka's score and X-rays using Hawkins classification. Fractures occurred during sports in 19 cases. The most frequent mechanism was association of dorsal flexion and pronation. There were associated lesions in 44% of cases. RESULTS: In the delayed diagnosis group, we found 14 cases of associated pseudarthrosis and subtalar osteoarthritis, two cases of isolated pseudarthrosis and two cases of isolated subtalar osteoarthritis. After treatment, the result at the last follow-up was excellent in 15 of these cases (50%), good in seven cases (23%), fair in seven cases (23%) and poor in one case (4%). In the immediate diagnosis group, five of 14 patients had at least one complication: 29% pseudarthrosis and 29% subtalar osteoarthritis. After treatment, the result at the last follow-up in this group was excellent in eight cases (58%), good in four cases (28%) and fair in two cases (14%). Immediate diagnosis was correlated with better results at the last follow-up. In the immediate diagnosis group, among patients who had orthopedic treatment, the rate of secondary surgery was 42%. CONCLUSION: Fracture of the lateral process of the talus is quite frequent and occurs among young people. Spontaneous progression is severe, with two major complications: pseudarthrosis and subtalar osteoarthritis. Treatment is always required in case of displaced fracture.