Background. The cavovarus foot is a complex 3-dimensional deformity. Although a multitude of techniques are described for its surgical management, few of these are evidence based or guided by classification systems. Surgical management involves realignment of the hindfoot and soft tissue balancing, followed by forefoot balancing. Our aim was to classify the pattern of residual forefoot deformities once the hindfoot is corrected, to guide forefoot correction. Methods. We included 20 cavovarus feet from adult patients with Charcot-Marie-Tooth who underwent weightbearing CT (mean age 43.4 years, 14 males). Patients included had flexible deformities, with no previous surgery. Previous work established majority of rotational deformity in cavovarus feet occurs at the talonavicular joint, which is often reduced during surgery. Using specialised software (Bonelogic 2.1, Disior) a 3-dimensional, virtual model was created. Using data from normal feet as a guide, the talonavicular joint of the cavovarus feet was digitally reduced to a ‘normal’ position. Models of the corrected position were exported and geometrically analysed using Blender 3.6 to identify anatomical trends. Results. We identified 3 types of cavovarus forefoot morphotypes. Type 1 was seen in 13 cases (65%) and was defined as a foot where only the first metatarsal was relatively plantarflexed to the rest of the foot, with no significant residual adduction after talonavicular correction. Type 2 was seen in 4 cases (20%) and was defined as a foot where the second and first metatarsals were progressively plantarflexed, with no significant adduction. Type 3 was seen in 3 cases (15%) and was defined as a foot where the metatarsals were still adducted after talonavicular de-rotation. Conclusion. We classify 3 forefoot morphotypes in cavovarus feet. It is important to recognise and anticipate the residual forefoot deformities after hindfoot correction as different treatment strategies may be required for different morphotypes to achieve balanced correction

Periprosthetic joint infection (PJI) is a difficult complication requiring a comprehensive eradication protocol. Cure rates have essentially stalled in the last two decades, using methods of antimicrobial cement joint spacers and parenteral antimicrobial agents. Functional spacers with higher-dose antimicrobial-loaded cement and antimicrobial-loaded calcium sulphate beads have emphasized local antimicrobial delivery on the premise that high-dose local antimicrobial delivery will enhance eradication. However, with increasing antimicrobial pressures, microbiota have responded with adaptive mechanisms beyond traditional antimicrobial resistance genes. In this review we describe adaptive resistance mechanisms that are relevant to the treatment of PJI. Some mechanisms are well known, but others are new. The objective of this review is to inform clinicians of the known adaptive resistance mechanisms of microbes relevant to PJI. We also discuss the implications of these adaptive mechanisms in the future treatment of PJI.

Cite this article: Bone Joint J 2022;104-B(5):575–580.

Aims

Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement.

Introduction and Objective. To estimate the prevalence of acetabular ossifications in the adult population with asymptomatic, morphologically normal hips at CT and to determine whether the presence of labral ossifications is associated with patient-related (sex, age, BMI), or hip-related parameters (joint space width, and cam- and pincer-type femoroacetabular impingement morphotype). Materials and Methods. We prospectively included all patients undergoing thoracoabdominal CT over a 3-month period. After exclusion of patients with a clinical history of hip pathology and/or with signs of osteoarthritis on CT, we included a total of 150 hips from 75 patients. We analyzed the presence and the size of labral ossifications around the acetabular rim. The relationships between the size of labral ossifications and patient- and hip-related parameters were tested using multiple regression analysis. Results. The prevalence of labral ossifications in this population of asymptomatic, non-OA hips was 96% (95%CI=[80.1; 100.0]). The presence of labral ossifications and their size were correlated between right and left hips (Spearman coefficient=0.64 (95%CI=[0.46; 0.79]), p<0.05)). The size of labral ossifications was significantly associated with age (p<0.0001) but not with BMI (p=0.35), gender (p=0.05), joint space width (p≥0.53 for all locations) or any of the qualitative or quantitative parameters associated with femoroacetabular morphotype (all p≥0.34). Conclusions. Labral ossifications are extremely common in asymptomatic, non-osteoarthritic hips. Their size is not correlated with any patient-, or hip-related parameters except for the age. These findings suggest that the diagnosis of osteoarthritis or femoroacetabular impingement morphotype should not be made based on the sole presence of acetabular labral ossifications

Trochlear dysplasia is a specific morphotype of the knee, characterized by but not limited to a specific anatomy of the trochlea. The notch, posterior femur and tibial plateau also seem to be involved. In our study we conducted a semi-automated landmark-based 3D analysis on the distal femur, tibial plateau and patella. The knee morphology of a study population (n=20), diagnosed with trochlear dysplasia and a history of recurrent patellar dislocation was compared to a gender- and age-matched control group (n=20). The arthro-CT scan-based 3D-models were isotropically scaled and landmark-based reference planes were created for quantification of the morphometry. Statistical analysis was performed to detect shape differences between the femur, tibia and patella as individual bone models (Mann-Whitney U test) and to detect differences in size agreement between femur and tibia (Pearson's correlation test). The size of the femur did not differ significantly between the two groups, but the maximum size difference (scaling factor) over all cases was 35%. Significant differences were observed in the trochlear dysplasia (TD) versus control group for all conventional parameters. Morphometrical measurements showed also significant differences in the three directions (anteroposterior (AP), mediolateral (ML), proximodistal (PD)) for the distal femur, tibia and patella. Correlation tests between the width of the distal femur and the tibial plateau revealed that TD knees show less agreement between femur and tibia than the control knees; this was observed for the overall width (TD: r=0.172; p=0.494 - control group: r=0.636; p=0.003) and the medial compartment (TD: r=0.164; p=0.516 - control group: r=0.679; p=0.001), but not for the lateral compartment (TD: r=0.512; p=0.029 - control: r=0.683; p=0.001). In both groups the intercondylar eminence width was strongly correlated with the notch width (TD: r=0.791; p=0.001 - control: r=0.643; p=0.002). The morphology of the trochleodysplastic knee differs significantly from the normal knee by means of an increased ratio of AP/ML width for both femur and tibia, a smaller femoral notch and a lack of correspondence in mediolateral width between the femur and tibia. More specifically, the medial femoral condyle shows no correlation with the medial tibial plateau

Aims

The diversity of femoral morphology renders femoral component sizing in total hip arthroplasty (THA) challenging. We aimed to determine whether femoral morphology and femoral component filling influence early clinical and radiological outcomes following THA using fully hydroxyapatite (HA)-coated femoral components.

Background. The knee joint morphology varies according to gender and morphotype of the patients. Objectives. To measure the dimensions of the proximal tibia and distal femur of osteoarthritic knees in a group of patients from the same ethnic group (Arabs) and to compare these measurements with the dimensions of six total knee implants. Patients and methods. Three-dimensional CT reconstructions were used to collect morphologic data from 124 osteoarthritic knees. Anteroposterior and mediolateral measurements were obtained from tibial and femoral bony resection surfaces planned for patient-specific instrumentation (Figures 1 and 2). These measurements were compared to the dimensions for six different types of knee implants. Results. The average tibial mediolateral (tML) and tibial anteroposterior (tAP) measurement for the study group were 74.36±6 mm and 48.94±4.57 mm, respectively; the medial tibial plateau was larger than lateral. The average femur mediolateral (fML) and femur anteroposterior (fAP) measurements for the same group were 72.04±6.6 and 68.1±7.75, respectively. For implant matching, the average tibial aspect ratio was 152.62±12.66 and the femoral average aspect ratio was 106.37±14.34. Differences were found between morphometric measurements of males and females with significantly higher parameters for males when compared to female when compared in AP and mediolateral dimensions. Also, 22.5% of the operated knees had mismatch within 2 size of the same implant. Conclusion. There is significant asymmetry of proximal tibial plateau and femur condyles. Our data suggest mismatch between osteoarthritic Arabian knees and implant designs. These ethnic differences should be considered when designing knee implants

Aims

Analysis of the morphology of the distal femur, and by extension of the femoral components in total knee arthroplasty (TKA), has largely been related to the aspect ratio, which represents the width of the femur. Little is known about variations in trapezoidicity (i.e. whether the femur is more rectangular or more trapezoidal). This study aimed to quantify additional morphological characteristics of the distal femur and identify anatomical features associated with higher risks of over- or under-sizing of components in TKA.

Introduction. The gold standard for knee surgery is the restoration of the so-called «neutral mechanical alignment ». Recent literature as pointed out the patients with «constitutional varus »; in these cases, restoring neutral alignment could be abnormal and even undesirable. The same situation can be observed in patients with «constitutional valgus alignment ». To date, these outliers cases have only been explored focusing on the lower limb; the influence of the pelvic morphotype has not been studied. Intuitively, the pelvic width could be a significant factor. The EOS low dose imaging technique provides full body standing X-rays to evaluate the global anatomy of the patient. This work explores the influence of the pelvic parameters on the frontal knee alignment. Material and methods. – We included 170 patients (340 lower extremities). 2 operators performed measurements once per patient on AP X-rays. The classical anatomical parameters were:. –. Femoral mechanical angle (FMA). –. Tibial mechanical angle (TMA). –. Hip knee shaft angle (HKS). –. Hip knee ankle angle (HKA). –. Femoral and tibial lengths. The morphotype was evaluated by:. –. the distances between the center of two femoral heads (FHD), between knees (KD) and between ankles (AD). –. the medial neck-shaft angle (MNSA). –. the femoral offset. The horizontal distance between the limb mechanical axis (line passing from center of the femoral head to the center of the ankle) and the center of the knee was called the intrinsic mechanical axis deviation (IMAD) (fig 1). The horizontal distance between the pelvic mechanical axis (line from the center of the sacral plate to the center of the ankle) and the center of the knee was called the global mechanical axis deviation (GMAD) (fig 2). Inter-Operator Reliability was calculated with Intra-class Correlation Coefficient (ICC) and Inter-Reader Agreement was assessed with Bland-Altman test. A relationship between IMAD and GMAD to the other parameters was assessed using Pearson's correlation coefficient. Results. Inter-Operator Reliability was high for femoral offset, TMA and MSNA (ICC > 0,88) and very high for the other parameters (ICC > 0,93). These values are given in table 1 and all the 2D parameters are given in the table 2. IMAD was significantly correlated with HKA (r = 0,99), FMA (r = −0,58), TMA (r = −0,61) and KD (r = 0,72). GMAD was significantly correlated with HKA (r = 0,94), FMA (r = −0,53), TMA (r = −0,60) and KD (r = 0,67). Two groups were identified according to pelvic width (FHD):. Group 1 (standard patients): Pelvic width < 18 cm (164 lower extremities). Group 2 (wide pelvis): Pelvic width ≥ 18 cm (176 lower extremities). For standard patients the FHD is a significant parameter, whereas the proximal femoral anatomy (offset and MNSA) are more relevant for wide pelvis. Conclusion. Accurate analysis of the morphotype of the lower limbs is essential for planning femoral or tibial osteotomy and knee prostheses. Taking into account pelvic morphotype can provide additional informations for the axes restoration and the detection of outliers patients

The June 2015 Hip & Pelvis Roundup³⁶⁰ looks at: neuraxial anaesthesia and large joint arthroplasty; revision total hip arthoplasty: factors associated with re-revision surgery; acetabular version and clinical outcomes in impingement surgery; hip precautions may be ineffective; implant selection and cost effectiveness; femoroacetabular impingement in the older age group; multiple revision in hip arthroplasty

Introduction:. Recent studies have concluded that gender influences hip morphology at the time of surgery as well as dysplastic development of the hip. This may lead to a particular choice of implant including stem design and/or neck modularity. In this study we hypothesized that not only gender but also morphotype and etiology (primary osteoarthritis versus aseptic osteonecrosis) may be a significant factor to predict the anatomy of the hip at the time of total hip arthroplasty (THA). Methods:. We reviewed 690 patients undergoing THA for primary arthritis (OA) or avascular osteonecrosis (AVN) between April 2000 and June 2005 and stratified each into three groups based on their anatomic constitution: endomorph (EN), ectomorph (ECT), or mesomorph (ME) (determined by the ratio: pelvic width/total leg length measured on full-length X-rays). Two independent observers measured twice four parameters on preoperative CT scan: neck-shaft-angle angle (NSA), femoral offset value (FO), helitorsion (Ht) value and femoral neck anteversion (Av). Results:. No significant difference were observed between men and women for the four parameters with respectively: NSA (129.29° ± 5.6 versus 129.3° ± 5.7), Av (20.3° ± 8.6 versus 20.27° ± 8.6), FO (19.7 mm ± 3.98 versus 19.74 mm ± 3.98) and Ht (19.97° ± 12.2 for men and 19.94° ± 12.3). Significant difference were found for NSA: 130.1° ± 5.8 for ECT, 129.55° ± 6 for MES and 128.2° ± 5,1 for EN with p < 0.01. For Av, the values were: 18.9° ± 8.7 for ECT, 20.74° ± 8.1 for MES and 21.2° ± 8.95 for EN (p < 0.01). For FO the values were 19.1 mm ± 3.9 for ECT, 19.7 ± 4 for MES and and 20.44 mm ± 3.93 for EN (p < 0.01). No difference was found for Ht between the 3 groups. A significant difference was found between patients suffering from OA and AVN: mean NSA was 130.36° ± 8.79 for OA patients versus 127.35° ± 8.38 for those who had an AVN (p < 0.01). A value was 17.06° ± 8.1 for OA and 23.7 ± 7.89 for AVN (p < 0.01). FO value was 18.72 mm ± 3.71 for OA versus 20.75 mm ± 4.15 for AVN (p <0.01). And Ht was 18.94° ± 9.64 for OA and 21.05° ± 14.5 for AVN patients (p < 0.01). Discussion and conclusion:. Patients with short and wide morphotype (endomorph) had, irrespective of gender, lower values of NSA with greater anterversion and offset values, whereas patients with long and narrow morphotype (ectomorph) had higher values of NSA and smaller Av and FO (figure 1). In the same time patients suffering from AVN have lower NSA angle, lower Av, smaller FO and Ht (figure 2). Femoral stem design should allow the consideration of these differences to optimize the reconstruction of the hip at the time of THA including pre-operative and intra-operative modularity

More than two thirds of TKA are performed on women. Most TKA systems are based on the male anatomy. Therefore one could ask if a women specific design is needed in Knee Arthroplasty. There are two distinct types of distal femur: the normal one and the narrow one. In the narrow femur the problem of overhang can occur because for a given AP dimension (sizing of the implant) the corresponding ML dimension is too large. Many years ago these findings were already published in different articles. It is only in recent years that interest came from the industry. In our department a study project was initiated in January 2006. This led to the development of the Stature Femoral component for the Advance Medial Pivot knee prosthesis. The first one was implanted in June 2007 and since then it is used in 60% of our female patients and 11% in our male patients. The reason why it is quite often used in male patients is because not only gender influences distal femoral geometry but also morphotype is an important factor. Therefore irrespective of gender, ectomorphs will have smaller ML ratios and thus will have smaller knees and will benefit from a Stature variant. Moreover we have seen that the correct use of the Stature variant can also influence our clinical scores and our percentages of ligament releases with overall better results

We retrospectively examined the long-term outcome of 96 asymptomatic hips in 96 patients with a mean age of 49.3 years (16 to 65) who had radiological evidence of femoroacetabular impingement. When surveillance commenced there were 17, 34, and 45 hips with cam, pincer, and mixed impingement, respectively. Overall, 79 hips (82.3%) remained free of osteoarthritis for a mean of 18.5 years (10 to 40). In contrast, 17 hips (17.7%) developed osteoarthritis at a mean of 12 years (2 to 28). No statistically significant difference was found in the rates of development of osteoarthritis among the three groups (p = 0.43). Regression analysis showed that only the presence of idiopathic osteoarthritis of the contralateral diseased hip was predictive of development of osteoarthritis on the asymptomatic side (p = 0.039).

We conclude that a substantial proportion of hips with femoroacetabular impingement may not develop osteoarthritis in the long-term. Accordingly, in the absence of symptoms, prophylactic surgical treatment is not warranted.

Recently, gender-specific designs of total knee replacement have been developed to accommodate anatomical differences between males and females. We examined a group of male and female distal femora matched for age and height, to determine if there was a difference in the aspect ratio (mediolateral distance versus anteroposterior distance) and the height of the anterior flange between the genders. The Hamann-Todd Collection provided 1207 skeletally mature cadaver femora. The femoral length, the anteroposterior height, height of the lateral and medial flanges and the mediolateral width were measured in all the specimens. The mechanical axis of the femur, the cut articular width and the aspect ratio were assessed. Statistical analysis of the effect of gender upon the aspect ratio and the lateral and medial flanges was undertaken, controlling for age, height and race.

The mean aspect ratio of male femora was 1.21 (sd 0.07) and of female femora it was 1.16 (sd 0.06) (p < 0.001). There was no significant difference between male and female specimens in the mean size of the lateral flange (6.57 mm (sd 2.57) and 7.02 mm (sd 2.36), respectively; p = 0.099) or of the medial flange (3.03 mm (sd 2.47) and 3.56 mm (sd 2.32), respectively; p = 0.67). Future work in the design of knee prostheses should take into account the overall variability of the anatomy of the distal femur.

Introduction: To guide one’s surgical options if conservative treatment in metatarsalgia fails, a good understanding of the anatomy and the biomechanics of a normal forefoot is primordial. The recognition of a so-called ideal morphotype may serve as a guide, through technical or other means (clinical examination, X-rays, baropodometry,..), to obtain a calculated and subtle reconstruction of all the symptomatic elements. Material and Methods: Between 2000 and 2005, 68 patients were operated by the same surgeon and were all, but five, reviewed retrospectively by an independent examiner. The study of the 184 osteotomies performed (of which 177 Weil osteotomies), made use of clinical, and radiological computerised analysis. Results: We have not been able to find a significant correlation between a harmonious curve of Maestro and postoperative recurrence or transfert metatarsalgia. Discussion: The cause of transfert metatarsalgia is often hard to find. Known, and so evitable, are important shortening and a fault in the preoperative adjustment. Despite a precise preoperative planning and a perfectly performed surgical technique, the surgeon sometimes encounters the development of plantar callosities beneath metatarsal heads adjacent to the operated ones. Lots of variables are still unknown or not recognised: mobility at the Lisfranc, gastrocnemius retraction. We have noted a significant relationship between the preoperative (in-)stability and the risk of developing transfert metatarsalgia (p-value = 0.03). A metatarso-phalangeal articulation, unstable in the preop setting, has 0.36 times less the risk of leading to this complication than if the operation was performed on a stable articulation preoperatively. A stable articulation would so be an indirect sign of a good tolerance by the adjacent rays. Conclusion: One can question if the reconstruction of an architectural harmonious forefoot using the ideal curve of Maestro at any price is necessary, since we were not able do demonstrate a guaranteed postoperative pain relief. A respect of the so-called ideal morphotype of the forefoot on the dorsoplantar upright X-rays seems insufficient in the assurance of a balanced distribution of plantar pressures postoperatively. Certainly, this morphotype most probably avoids an elevated rate of complications, but may not be considered as the only criteria to be achieved. The clinical examination stays the most essential element. Only the preoperatively symptomatic and unstable metatarsals should probably undergo this osteotomy

New developments in osteotomy techniques and methods of fixation have caused a revival of interest of osteotomies around the knee. The current consensus on the indications, patient selection and the factors influencing the outcome after high tibial osteotomy is presented. This paper highlights recent research aimed at joint pressure redistribution, fixation stability and bone healing that has led to improved surgical techniques and a decrease of post-operative time to full weight-bearing.

Purpose of the study: The objective was to compare the results of ligamentoplasties with two commonly used grafts, hamstring and patellar tendon. This was a prospective randomized study. Material and methods: Between January 2001 and June 2004, 98 patients with an acute or chronic anterior cruciate ligament (ACL) tear with joint instability were included in this randomized study for arthroscopic repair. Patients were randomized to the patellar or hamstring arm. Clinical assessment was based on laxity, IKDC score, Lyscholm score, pain visual analog scale (VAS), midthigh thickness and isokinetic assessment at three months. Measurements were recorded preoperatively and at 1, 3, 6 weeks and 3, 6, and 12 months. Results: The two groups were comparable regarding gender, morphotype, associated lesions, and activity level. There was no difference in operative time or in recovery of complete extension. Anterior laxity was the same in the two groups. The isokinetic deficit appeared to be greater in the bone-tendon-bone group at three months. The IKDC and Lysholm scores were not significantly different at six and twelve months. Harvesting site morbidity was more pronounced in the bone-tendon-bone group. Conclusion: The two techniques provide good results. The bone-tendon-bone technique appears to cause greater harvesting site morbidity. While the isokinetic results appear to be better in the hamstring group, the measurements of laxity and recovery of stability did not show any difference

Purpose of the study: Compar the position of the femoral piece in relation to the transepicondylar axis (TEA) using four different techniques for regulating rotation:. cut parallel to the posterior bicondylar line (BCL),. 3° external rotation,. spacer method,. application of the formula: rotation = 1° + space in extension/2. Material and methods: One hundred patients who underwent total knee arthroplasty (TKA) had a preoperative computed tomography (CT) scan. The surgical transepicondylar axis (TEA) and the BCL were drawn on the horizontal slices. The angle measured between these two lines (1.56°–2.5°) determined the theoretical angle of external rotation for aligning the femoral piece on the TEA. During the operation, femoral valgus was set to the HKS angle, measured by goniometry. The knife of the distal femoral cut, materializing the line perpendicular to the mechanical femoral axis, came in contact with the most distal femoral condyle (generally the medial condyle but occasionally the lateral condyle for varus femurs). The distance d between the knife and the most distal point of the condyle which remained distant was then measured. The external rotation was set at 0° and 3° with the techniques 1) and 2). For the technique 3), the asymmetry of the distal cut was projected on the posterior cut leading to an automatic rotation at an angle calculated trigonometrically. For the technique 4), the rotation was calculated as a function of the distance d. The difference between the external rotation obtained for each of these techniques and the theoretical rotation was calculated for each patient. Results: The mean error of rotation obtained for the four techniques was respectively: 2.2–1.9°; 2–1.7°; 1.8–2.2°; and 1.5–1.4° (p< 0.05). The rate of malrotations greater than 1° for the four techniques was respectively: 60%, 58%, 41% and 36%. The rate of malrotations greater than 2° was respectively: 45%, 44%, 27% and 21%. This rate varied according to the femoral morphotype. The percentage of malrotations greater than 2° by technique was as follows for femoral morphotypes normal, varus, and valgus: technique 1: 37,34,58%; technique 2: 37,53,40%; technique 3: 7.5,9,26%; technique 4:22,30,40%. Conclusion: Interindividual variations in the TEA-BCL angle explain the high rate of malrotation after regulated rotation. An adapted regulation will enable lesser risk of error. An adaptation taking into consideration the results of the preoperative CT scan appear to provide the most reliable results

Purpose of the study: The aim of this retrospective epidemiological study was to report the complete arthroscopic results concerning meniscus or cartilage injuries for procedures performed to repair the anterior cruciate ligament (ACL). The goal was to search for risk factors and improve patient care. Material and methods: Between 2000 and 2004, the same operator performed 129 consecutive ligamentoplasties to repair ACL tears. The following preoperative factors were analyzed: body weight, height, type and level of sports activity, laxity, positive pivot test, morphotype, time from accident to surgery. Meniscal lesions were identified and classified according to Trillat. The Beguin and Locker classification was used for cartilage lesions. The Panthéon-Sorbonne statistics laboratory performed the statistical analysis. Results: Meniscal lesions were found in 53.5% of knees and cartilage lesions in 24.2%. The medial meniscus was involved in 75.4% and the lateral meniscus in 20.3%, both in 4.3%. The injury could be repaired by suture or a conservative procedure for 45%. The medial compartment presented cartilage injury in 51.6% of knees, the patella in 29%, the trochlea in 19.35% and the same percentage for the lateral condyle. The degree of preoperative laxity, the time from accident to surgery and body mass index were statistically correlated with presence of a meniscal injury. Age, the degree of pre-operative laxity and body mass index were statistically correlated with presence of a cartilage injury. Discussion: Meniscal injuries are frequent in knees with ACL tears. The posterior segment of the medial ligament, which blocks anterior translation of the tibia if the ACL is absent, is predominantly involved. The amount of tibial movement below the femur and stress applied to the knee (particularly related to body mass) favor such lesions. Many lesions will heal spontaneously after surgery. Inversely others are more frequent after a longstanding tear. Cartilage injury is also frequent and occurs often on aging cartilage. The extent of tibial movements and their repetition as well as important stress are factors predictive of such injuries. Conclusion: Indications for reconstruction of the ACL in the young subject are well identified, less so in the older subject. This study confirms the usefulness of reconstructing the ACL to protect the menisci and joint cartilage. Excessive weight appears to be another important point to take into consideration for the surgical management of these patients

Near 70% of failures of knee arthroplastys due to septic or aseptic mobilization are complicated because of massive loss of bone stock. In these cases surgeon have to perform a salvage procedure to restore legamentous balance, articular plane direction and axes of lower limb, finally to fill bone defects. Today intrinsic biomechanical stability of revision implant is entrust to sophisticated design and materials of custom made and modular implants. Endomedullary stem has to assolve specific functions: mechanical stability contrasting stress due to the boneloss, offering support for omoplastic or spongious bone innests in femoralor tibial defects. There are paucity of study in literature about dimension and morphology of endomedullary canal, probably because of variability between periostal andendostal anatomy in each patients, specially age related. This date has conditioned production of several number of revision stem size for all population. This anthropometric study verify presence of a particular regionin femoral and tibial endomidullar canal not dependent from sex, height, morphotype, important for a good press-fit of revision stem. Morphological date of midfemoral and tibial geometry was assessed in 50 subjects using Axial Computerized Tomography. Eleven (22%) were in men, thirty nine (78%) were in woman, with avarage of 73 years old (from 57 to 85). Exclusion criteria were previous operation at the same limb, deformity, pathology of bone metabolism. The level of sections were at 20, 18, 16 and 12 centimiters from articular plane for femur and at 8, 10, 13, 16 cm for tibia. Preliminar Ct scan with hight resolution program with bone alghoritm was performed. Axial view of any section was visualized at real dimension and maximal and minimal diameter of sections e were measured in millimiters. Areas of any section is different in each patient; this variability is greater near articular plane. Infact in our sample SD (Standard Deviation) of diameters of proximal femoral and distal tibialsections was lesser than SD of the other measurements. No difference of results about sex was noted. On base of these measuremts more proximal two femoral sections and two more distal tibial sections were considered to elaborate an ideal area for anchorage zone of anatomical revision stem. We subdivided all sample in five groups with homogeneous value of diameter in selected sections. For any groups tangent & #945; of an ideal trunk of cone including maximum and minimum value of diameter considered was computed, and the relative inclination angle. In our sample the greatest diameter in proximal femoral section was 20 mm and the lowest 10 mm; for tibial measuremnts the greatest value in distal tibial level was 18 mm and the lowest was 10 mm. Inclination angle was ever around 2° in all groups. Moreover we have calculated the presumable length of an ideal trunk of cone that includes the minimum and maximum value of femural and tibial diameter measured. About 5% of knee arthroplastys is destinated to an unsuccessfull. In many cases loosing of bone stock is huge and localized near articular plane. Afterward it’s important to restore biomechanical stability through endomedullary stem of revision implant. There are not many reports about morphology and anatomical study of femoral and tibial endomedullary canal. Many authors focus the attention on bone density or functional axes of the lower limb. Some authors studied remodelling process age-related about periostal ad endostal bone; cortical area undergoing thinning specially over fourthy years old. Our sample had mean of 73 years old: remodelling process is almost complete and then it is a good referenceto extrapolate real data about endomedullary morphology and width. Variability of data in all population about diameter of endomedullarycanal is lesser near femoral and tibial istmo, in particular around 18–20 cm from articular plane for femur and at 13–16 cm for tibia In our opinion short stem can’t guarantee good press-fit because of extreme variability of diameters in the population near knee. This anthropometric study confirm presence of anatomical area of the midfemural and tibial canal with common geometric characteristic in allpatient; it can be used to realize an anatomical stem that guarantees a good contact bone/prosthesis and then an optimal bone integration. On base of our results it is possibile realize few revision stem because in all groups of patients studied at 18–20 cm from knee for femur and at 13–16 cm for tibia, angle of inclination was ever 2°