In recent years, the use of computed tomography (CT) has made it possible to obtain without distortion images of axial sections of the patella with the knee in the first 15°–20° of flexion.

We performed CT examinations on 27 patients aged between 11 and 17 years. We considered patients who had anterior knee pain with or without a feeling of patellar instability. CT examinations were performed with the knee flexed to 15° with and without quadriceps contraction. The tomograms obtained were analysed considering: (1) the congruence angle (CA), (2) the patellar tilt angle (PTA), (3) the sulcus angle (SA) and (4) trochlear depth (TD). We performed CT examinations on a control group of 20 patients aged between 11 to 17 years. Statistical analysis was performed by using the analysis of variation (ANOVA) test or the Student’s t-test on paired or unpaired data.

The difference between control knees and symptomatic knees was significant for all of the CT variables (unpaired t-test). Malalignment detected with the quadriceps relaxed was typed according to the classification of Schutzer et al. as follows: type I – lateralised patella, 13 knees (24.1%); type II – lateralised and tilted patella, 24 knees (44.4%); and type III – tilted patella, 12 knees (22.2%). In 26 knees (48.2%), CT examination with quadriceps in contraction gave the same findings as CT examination with the quadriceps relaxed, i.e. type and severity of malalignment were identical. In the remaining 28 knees (51.8%), CT examination with the quadriceps in contraction gave different results from the CT examination with the quadriceps relaxed.

The greater sensitivity and specificity of CT as compared with conventional radiographic methods in the diagnosis of patellofemoral malalignment have been demonstrated. Our results show that there is a relationship between clinical findings and CT data. CT assessment with the quadriceps relaxed permitted us to divide the knees into three types of patellofemoral malalignment. To our knowledge, not many studies have been performed with the quadriceps contracted. In the present study, in 48.2% of knees there were no differences between CT assessment with the quadriceps relaxed and with the quadriceps contracted in either type or severity of malalignment. In contrast, in the remaining 51.8% of symptomatic knees we found differences.

Before planning an operation in patients with anterior knee pain with or without patellar instability, CT assessment both with the quadriceps relaxed and contracted permits a reliable documentation of malalignment, permitting the surgeon to select the optimal treatment.

Torsional changes in the lower limbs represent a serious clinical problem. The evaluation of the physiological development of the relationship between femur and tibia in the axial plane is necessary for final assessment.

The authors observed 940 patients aged from 4 to 15 years to identify the most important modifications of torsion of the lower limbs during paediatric age. Clinical examination includes assessment in the standing and supine position and observation of the gait features so that the physiological-pathological borderline can be defined, along with peculiar aspects of single and combined deformities, in order to identify indications for osteotomy.

The types of torsion are classified as: (1) isolated augmentation of femoral anteversion; (2) isolated reduction of femoral anteversion; (3) isolated medial tibial torsion; (4) isolated lateral tibial torsion; and (5) combined torsion (femoral anteversion combined with lateral tibial torsion).

The anatomy and the natural progression of femoral and tibial torsion can be assessed by clinical methods. Radiographic methods such as axial CT views are indicated in cases in which clinical examination does not provide clear information and, in particular, if qualitative and quantitative diagnosis is required in order to establish the therapeutic protocol.

The authors conclude by suggesting that the physiological development of torsion should be followed up to skeletal maturity in order to make a general evaluation and to decide on treatment.

Fixation by a single screw is considered the current treatment of choice for a slipped capital femoral epiphysis. This approach promotes premature physeal closure. The use of a modified, standard, single, cannulated screw designed to maintain epiphyseal fixation without causing premature closure of the physis was reviewed in ten patients. The nine boys and one girl aged between 10.6 and 12.6 years with unilateral slipped capital femoral epiphysis (SCFE), were markedly skeletally immature (Tanner stage I, bone age 10 to 12.6 years).

Clinical and radiological review at a mean follow-up of 44.3 months (36 to 76) showed no difference in the time to physeal closure between the involved and uninvolved side. Measurement of epiphyseal and physeal development showed continued growth and remodelling in all patients.

Use of this device provided epiphyseal stability and maintained the capacity for physeal recovery and growth following treatment for both unstable and stable slipped capital femoral epiphysis.

We performed intra-articular reconstruction of the anterior cruciate ligament (ACL) with the semitendinosus tendon placed in 2 mm diameter tunnels in 21 skeletally immature rabbits. The operation caused 11% damage to the physis of the femur on the frontal plane and 3% of its cross-sectional area but no alteration of growth or axial deviation of the bone resulted. In the tibia, the operation caused 12% damage to the physis in the frontal plane and 4% of the cross-sectional area. Two tibiae developed valgus deformities and one was shortened. Histological examination showed no areas of epiphysiodesis. There was no abnormality of growth-plate thickness in the two cases of tibia valga. Osseous metaplasia in the grafted tendons did not occur. The results suggest the need for careful evaluation of the percentage of damage to the growth plate before using intra-articular methods for reconstruction of the anterior cruciate ligament in adolescents.

We obtained specimens of growth-plate cartilage from four patients with osteogenesis imperfecta. Light microscopy showed structural changes in the tissue and morphological changes in chondrocytes and matrix, particularly in the hypertrophic zone. There were changes in the process of calcification in the primary mineralisation zone of the cartilage. We also found histochemical changes in the matrix glycosaminoglycans (GAGs) in the zones where physiological mineralisation was disturbed and where the trabeculae were interrupted and poorly mineralised. In addition to the known molecular defects in collagen, changes in GAGs and non-collagenous proteins are important factors in the pathogenesis of the disease.