The management of osteoarthritis of the knee associated with patellar instability secondary to external tibial torsion > 45° is challenging. Patellofemoral biomechanics in these patients cannot be achieved by intra-articular correction using standard techniques of total knee replacement. We reviewed seven patients (eight knees) with recurrent patellar dislocation and one with bilateral irreducible lateral dislocation who had undergone simultaneous total knee replacement and internal tibial derotational osteotomy. All had osteoarthritis and severe external tibial torsion. The mean follow-up was for 47.2 months (24 to 120). The mean objective and functional Knee Society scores improved significantly (p = 0.0001) from 29.7 and 41.5 pre-operatively to 71.4 and 73.5 post-operatively, respectively. In all patients the osteotomies healed and patellar stability was restored. Excessive external tibial torsion should be identified and corrected in patients with osteoarthritis and patellar instability. Simultaneous internal rotation osteotomy of the tibia and total knee replacement is a technically demanding but effective treatment for such patients

We reviewed 20 patients with spina bifida who had had surgical management of tibial torsion. Eight had had bilateral procedures and 12 a unilateral procedure, giving a total of 28 limbs for analysis. We performed closed osteoclasis on seven limbs and tibial osteotomy on 21. In the closed osteoclasis group six limbs (85%) had a good result after an average follow-up of nine years (2 to 22). All limbs developed postoperative anteromedial bowing of the tibia which later remodelled. In the tibial osteotomy group 19 (90%) had a good result. The average follow-up was nine years (2 to 28). Complications occurred in seven limbs (33%). We recommend closed osteoclasis of the tibia for the young patient with spina bifida in whom walking is impeded by excessive internal tibial torsion, and supramalleolar tibial osteotomy in the older patient with excessive external tibial torsion and a planovalgus foot

Measurements of tibial torsion using a tropometer were made in more than 1200 consecutive patients attending an adult knee clinic. In total 1672 readings from 836 patients in 11 diagnostic categories were analysed. Patients with either patellofemoral instability or Osgood-Schlatter disease had a significant increase in lateral tibial torsion. The most important finding was a significant reduction in this torsion in patients with panarticular disease

Previous clinical studies have studied tibiofibular torsion by measuring the angular difference between a proximal (often bicondylar) plane and a distal bimalleolar plane. We measured the angular difference between the proximal and distal posterior tibial planes as defined by ultrasound scans. We found no significant torsional difference between the right and left tibiae of 87 normal children, nor between their different age groups. The mean external torsion of 58 legs with congenital talipes equinovarus was 18 degrees; significantly less than the mean 40 degrees in the normal children and 27 degrees in the clinically normal legs of the 22 patients with unilateral congenital talipes equinovarus. We did not confirm the previously reported increase in external torsion with increasing age. The relative internal tibial torsion we have demonstrated in patients with congenital talipes equinovarus must be differentiated from the posterior displacement of the distal fibula observed by others and which may result from manipulative treatment. The relative internal tibial torsion we found in the clinically normal legs of children with congenital talipes equinovarus is further evidence that in this condition the pathology is not confined to the clinically affected foot

The development of lateral tibial torsion in the paralysed lower limb is well documented, but its pathogenesis is poorly understood. This paper attempts to provide an explanation for its development when it is associated with a varus or equinovarus deformity of the hindfoot. Correction of the lateral tibial torsion by supramalleolar derotation tibial osteotomy and reorientation of the ankle mortise appear to unlock the talus from the laterally rotated position, correcting a mobile hindfoot varus deformity and altering soft-tissue tensions about the ankle so that the correction achieved is maintained. In the presence of a fixed hindfoot deformity, supramalleolar derotation tibial osteotomy is useful as a first-stage procedure before corrective osteotomies of the foot. The operation described is technically simple and carries a low morbidity. Twenty supramalleolar derotation tibial osteotomies in 18 patients have been performed with satisfactory results and few complications

Patients with spina bifida cystica commonly have significant disability from a combination of valgus deformity of the ankle and subtalar joints with lateral tibial torsion and plano-abduction deformity of the foot. These deformities can be corrected by a single procedure which combines a supramalleolar tibial osteotomy with a lateral inlay triple fusion. This procedure was carried out on 20 feet in 15 patients and the results were reviewed after an average of three years (range 18 months to 7 years). In 75 per cent of feet the combination of deformities was fully corrected, ulcers and callosities were eliminated in 95 per cent, the use of calipers minimised in 95 per cent, and in all patients the problem of shoe-wrecking was reduced. Complications included recurrent valgus deformity, delayed union of the tibial osteotomy and failure of midtarsal fusion

A new method for the measurement of tibial torsion using computerised transverse tomography is presented. Its accuracy is equal to that of cadaveric skeletal measurement. This method may be used in patients with unilateral post-traumatic torsional deformities, especially when these are combined with genu varum or valgum. The study of torsional aberrations in connection with congenital abnormalities of the foot is of further interest

Aims. The prevalence of combined abnormalities of femoral torsion (FT) and tibial torsion (TT) is unknown in patients with femoroacetabular impingement (FAI) and hip dysplasia. This study aimed to determine the prevalence of combined abnormalities of FT and TT, and which subgroups are associated with combined abnormalities of FT and TT. Methods. We retrospectively evaluated symptomatic patients with FAI or hip dysplasia with CT scans performed between September 2011 and September 2016. A total of 261 hips (174 patients) had a measurement of FT and TT. Their mean age was 31 years (SD 9), and 63% were female (165 hips). Patients were compared to an asymptomatic control group (48 hips, 27 patients) who had CT scans including femur and tibia available for analysis, which had been acquired for nonorthopaedic reasons. Comparisons were conducted using analysis of variance with Bonferroni correction. Results. In the overall study group, abnormal FT was present in 62% (163 hips). Abnormal TT was present in 42% (109 hips). Normal FT combined with normal TT was present in 21% (55 hips). The most frequent abnormal combination was increased FT combined with normal TT of 32% (84 hips). In the hip dysplasia group, 21% (11 hips) had increased FT combined with increased TT. The prevalence of abnormal FT varied significantly among the subgroups (p < 0.001). We found a significantly higher mean FT for hip dysplasia (31°; SD 15)° and valgus hips (42° (SD 12°)) compared with the control group (22° (SD 8°)). We found a significantly higher mean TT for hips with cam-type-FAI (34° (SD 6°)) and hip dysplasia (35° (SD 9°)) compared with the control group (28° (SD 8°)) (p < 0.001). Conclusion. Patients with FAI had a high prevalence of combined abnormalities of FT and TT. For hip dysplasia, we found a significantly higher mean FT and TT, while 21% of patients (11 hips) had combined increased TT and increased FT (combined torsional malalignment). This is important when planning hip preserving surgery such as periacetabular osteomy and femoral derotation osteotomy. Cite this article: Bone Joint J 2020;102-B(12):1636–1645

Aims. Abnormal femoral torsion (FT) is increasingly recognized as an additional cause for femoroacetabular impingement (FAI). It is unknown if in-toeing of the foot is a specific diagnostic sign for increased FT in patients with symptomatic FAI. The aims of this study were to determine: 1) the prevalence and diagnostic accuracy of in-toeing to detect increased FT; 2) if foot progression angle (FPA) and tibial torsion (TT) are different among patients with abnormal FT; and 3) if FPA correlates with FT. Patients and Methods. A retrospective, institutional review board (IRB)-approved, controlled study of 85 symptomatic patients (148 hips) with FAI or hip dysplasia was performed in the gait laboratory. All patients had a measurement of FT (pelvic CT scan), TT (CT scan), and FPA (optical motion capture system). We allocated all patients to three groups with decreased FT (< 10°, 37 hips), increased FT (> 25°, 61 hips), and normal FT (10° to 25°, 50 hips). Cluster analysis was performed. Results. We found a specificity of 99%, positive predictive value (PPV) of 93%, and sensitivity of 23% for in-toeing (FPA < 0°) to detect increased FT > 25°. Most of the hips with normal or decreased FT had no in-toeing (false-positive rate of 1%). Patients with increased FT had significantly (p < 0.001) more in-toeing than patients with decreased FT. The majority of the patients (77%) with increased FT walk with a normal foot position. The correlation between FPA and FT was significant (r = 0.404, p < 0.001). Five cluster groups were identified. Conclusion. In-toeing has a high specificity and high PPV to detect increased FT, but increased FT can be missed because of the low sensitivity and high false-negative rate. These results can be used for diagnosis of abnormal FT in patients with FAI or hip dysplasia undergoing hip arthroscopy or femoral derotation osteotomy. However, most of the patients with increased FT walk with a normal foot position. This can lead to underestimation or misdiagnosis of abnormal FT. We recommend measuring FT with CT/MRI scans in all patients with FAI. Cite this article: Bone Joint J 2019;101-B:1218–1229

The anterior cruciate ligament (ACL) is frequently injured in elite athletes, with females up to eight times more likely to suffer an ACL tear than males. Biomechanical and hormonal factors have been thoroughly investigated; however, there remain unknown factors that need investigation. The mechanism of injury differs between males and females, and anatomical differences contribute significantly to the increased risk in females. Hormonal factors, both endogenous and exogenous, play a role in ACL laxity and may modify the risk of injury. However, data are still limited, and research involving oral contraceptives is potentially associated with methodological and ethical problems. Such characteristics can also influence the outcome after ACL reconstruction, with higher failure rates in females linked to a smaller diameter of the graft, especially in athletes aged < 21 years. The addition of a lateral extra-articular tenodesis can improve the outcomes after ACL reconstruction and reduce the risk of failure, and it should be routinely considered in young elite athletes. Sex-specific environmental differences can also contribute to the increased risk of injury, with more limited access to and availablility of advanced training facilities for female athletes. In addition, football kits are designed for male players, and increased attention should be focused on improving the quality of pitches, as female leagues usually play the day after male leagues. The kit, including boots, the length of studs, and the footballs themselves, should be tailored to the needs and body shapes of female athletes. Specific physiotherapy programmes and training protocols have yielded remarkable results in reducing the risk of injury, and these should be extended to school-age athletes. Finally, psychological factors should not be overlooked, with females’ greater fear of re-injury and lack of confidence in their knee compromising their return to sport after ACL injury. Both intrinsic and extrinsic factors should be recognized and addressed to optimize the training programmes which are designed to prevent injury, and improve our understanding of these injuries.

Cite this article: Bone Joint J 2023;105-B(10):1033–1037.

One-hundred and seventy patients with 252 club feet treated by early posterior release were reviewed after a follow-up averaging 15 years 10 months. The feet were assessed both functionally and clinically and the results related to any bony deformity found radiographically; a satisfactory result was obtained in 81%. Lateral tibial torsion was examined and found to be less than in a normal population. The relationship between primary bone deformity and eventual functional result was examined, and a classification of talar dome deformity introduced. The range of ankle movement was a major factor in determining the functional result, and this in turn was influenced by the degree of talar dome flattening. It is suggested that the primary bone deformity present at birth dictates the eventual result of treatment

Torsional deformities of the tibia are common in children, but in the majority both the torsion and the associated disturbance of gait resolve without intervention. There are, however, a significant number of children and adults with neuromuscular disease who present with pathological tibial torsion, which may require surgical correction. We conducted a prospective study in two centres, to investigate the outcome of supramalleolar derotation osteotomy of the tibia, using internal fixation with the AO-ASIF T plate. A range of outcome variables was collected, prospectively, for 57 patients (91 osteotomies), including thigh foot angle, foot progression angle, post-operative complications and serial radiographs. Correction of thigh foot angle and foot progression angle was satisfactory in all patients. Three major complications were recorded; one aseptic nonunion, one fracture through the osteotomy site after removal of the plate and one distal tibial growth arrest. We found that supramalleolar derotation osteotomy of the tibia, with AO-ASIF T plate fixation is an effective method for the correction of torsional deformities of the tibia and the associated disturbances of gait in children and adults with neuromuscular disease, with a 5.3% risk of major complications

Corrective osteotomies are often planned and performed on the basis of normal anatomical proportions. We have evaluated the length and torsion of the segments of the lower limb in normal individuals, to analyse the differences between left and right sides, and to provide tolerance figures for both length and torsion. We used CT on 355 adult patients and measured length and torsion by the Ulm method. We excluded all patients with evidence of trauma, infection, tumour or any congenital disorder. The mean length of 511 femora was 46.3 ± 6.4 cm (±2. sd. ) and of 513 tibiae 36.9 ± 5.6 cm; the mean total length of 378 lower limbs was 83.2 ± 11.4 cm with a tibiofemoral ratio of 1 to 1.26 ± 0.1. The 99th percentile level for length difference in 178 paired femora was 1.2 cm, in 171 paired tibiae 1.0 cm and in 60 paired lower limbs 1.4 cm. In 505 femora the mean internal torsion was 24.1 ± 17.4°, and in 504 tibiae the mean external torsion was 34.9 ± 15.9°. For 352 lower limbs the mean external torsion was 9.8 ± 11.4°. The mean torsion angle of right and left femora in individuals did not differ significantly, but mean tibial torsion showed a significant difference between right (36.46° of external torsion) and left sides (33.07° of external torsion). For the whole legs torsion on the left was 7.5 ± 18.2° and 11.8 ± 18.8°, respectively (p < 0.001). There was a trend to greater internal torsion in femora in association with an increased external torsion in tibiae, but we found no correlation. The 99th percentile value for the difference in 172 paired femora was 13°; in 176 pairs of tibiae it was 14.3° and for 60 paired lower limbs 15.6°. These results will help to plan corrective osteotomies in the lower limbs, and we have re-evaluated the mathematical limits of differences in length and torsion

Aims

The Oswestry-Bristol Classification (OBC) is an MRI-specific assessment tool to grade trochlear dysplasia. The aim of this study is to validate clinically the OBC by demonstrating its use in selecting treatments that are safe and effective.

Primary total knee arthroplasty (TKA) is a reliable procedure with reproducible long-term results. Nevertheless, there are conditions related to the type of patient or local conditions of the knee that can make it a difficult procedure. The most common scenarios that make it difficult are discussed in this review. These include patients with many previous operations and incisions, and those with severe coronal deformities, genu recurvatum, a stiff knee, extra-articular deformities and those who have previously undergone osteotomy around the knee and those with chronic dislocation of the patella.

Each condition is analysed according to the characteristics of the patient, the pre-operative planning and the reported outcomes.

When approaching the difficult primary TKA surgeons should use a systematic approach, which begins with the review of the existing literature for each specific clinical situation.

Cite this article: Bone Joint J 2015;97-B(10 Suppl A):30–9.

Femoral stem version has a major influence on impingement and early post-operative stability after total hip arthroplasty (THA).

The main objective of this study was to evaluate the validity of a novel radiological method for measuring stem version. Anteroposterior (AP) radiographs and three-dimensional CT scans were obtained for 115 patients (female/male 63/72, mean age 62.5 years (50 to 75)) who had undergone minimally invasive, cementless THA. Stem version was calculated from the AP hip radiograph by rotation-based change in the projected prosthetic neck–shaft (NSA*) angle using the mathematical formula ST = arcos [tan (NSA*) / tan (135)]. We used two independent observers who repeated the analysis after a six-week interval. Radiological measurements were compared with 3D-CT measurements by an independent, blinded external institute.

We found a mean difference of 1.2° (sd 6.2) between radiological and 3D-CT measurements of stem version. The correlation between the mean radiological and 3D-CT stem torsion was r = 0.88 (p < 0.001). The intra- (intraclass correlation coefficient ≥ 0.94) and inter-observer agreement (mean concordance correlation coefficient = 0.87) for the radiological measurements were excellent.

We found that femoral tilt was associated with the mean radiological measurement error (r = 0.22, p = 0.02).

The projected neck–shaft angle is a reliable method for measuring stem version on AP radiographs of the hip after a THA. However, a highly standardised radiological technique is required for its precise measurement.

Cite this article: Bone Joint J 2015; 97-B:306–11.

We report the outcome of 28 patients with spina bifida who between 1989 and 2006 underwent 43 lower extremity deformity corrections using the Ilizarov technique. The indications were a flexion deformity of the knee in 13 limbs, tibial rotational deformity in 11 and foot deformity in 19. The mean age at operation was 12.3 years (5.2 to 20.6). Patients had a mean of 1.6 previous operations (0 to 5) on the affected limb. The mean duration of treatment with a frame was 9.4 weeks (3 to 26) and the mean follow-up was 4.4 years (1 to 9). There were 12 problems (27.9%), five obstacles (11.6%) and 13 complications (30.2%) in the 43 procedures. Further operations were needed in seven patients. Three knees had significant recurrence of deformity. Two tibiae required further surgery for recurrence. All feet were plantigrade and braceable.

We conclude that the Ilizarov technique offers a refreshing approach to the complex lower-limb deformity in spina bifida.

Our goal was to evaluate the use of Ponseti’s method, with minor adaptations, in the treatment of idiopathic clubfeet presenting in children between five and ten years of age. A retrospective review was performed in 36 children (55 feet) with a mean age of 7.4 years (5 to 10), supplemented by digital images and video recordings of gait. There were 19 males and 17 females. The mean follow-up was 31.5 months (24 to 40). The mean number of casts was 9.5 (6 to 11), and all children required surgery, including a percutaneous tenotomy or open tendo Achillis lengthening (49%), posterior release (34.5%), posterior medial soft-tissue release (14.5%), or soft-tissue release combined with an osteotomy (2%). The mean dorsiflexion of the ankle was 9° (0° to 15°). Forefoot alignment was neutral in 28 feet (51%) or adducted (< 10°) in 20 feet (36%), > 10° in seven feet (13%). Hindfoot alignment was neutral or mild valgus in 26 feet (47%), mild varus (< 10°) in 19 feet (35%), and varus (> 10°) in ten feet (18%). Heel–toe gait was present in 38 feet (86%), and 12 (28%) exhibited weight-bearing on the lateral border (out of a total of 44 feet with gait videos available for analysis). Overt relapse was identified in nine feet (16%, six children). The parents of 27 children (75%) were completely satisfied.

A plantigrade foot was achieved in 46 feet (84%) without an extensive soft-tissue release or bony procedure, although under-correction was common, and longer-term follow-up will be required to assess the outcome.

Cite this article: Bone Joint J 2013;95-B:1721–5.

We describe three cases of infantile tibia vara resulting from an atraumatic slip of the proximal tibial epiphysis upon the metaphysis. There appears to be an association between this condition and severe obesity. Radiologically, the condition is characterised by a dome-shaped metaphysis, an open growth plate and disruption of the continuity between the lateral borders of the epiphysis and metaphysis, with inferomedial translation of the proximal tibial epiphysis. All patients were treated by realignment of the proximal tibia by distraction osteogenesis with an external circulator fixator, and it is suggested that this is the optimal method for correction of this complex deformity. There are differences in the radiological features and management between conventional infantile Blount’s disease and this ‘slipped upper tibial epiphysis’ variant.

We reviewed 34 knees in 24 children after a double-elevating osteotomy for late-presenting infantile Blount’s disease. The mean age of patients was 9.1 years (7 to 13.5).

All knees were in Langenskiöld stages IV to VI. The operative technique corrected the depression of the medial joint line by an elevating osteotomy, and the remaining tibial varus and internal torsion by an osteotomy just below the apophysis. In the more recent patients (19 knees), a proximal lateral tibial epiphysiodesis was performed at the same time.

The mean pre-operative angle of depression of the medial tibial plateau of 49° (40° to 60°) was corrected to a mean of 26° (20° to 30°), which was maintained at follow-up. The femoral deformity was too small to warrant femoral osteotomy in any of our patients. The mean pre-operative mechanical varus of 30.6° (14° to 66°) was corrected to 0° to 5° of mechanical valgus in 29 knees. In five knees, there was an undercorrection of 2° to 5° of mechanical varus. At follow-up a further eight knees, in which lateral epiphysiodesis was delayed beyond five months, developed recurrent tibial varus associated with fusion of the medial proximal tibial physis.

We studied the prevalence of severe crouch gait over a 15-year period in a defined population of children with spastic diplegia and Gross Motor Function Classification System levels II and III, to determine if there had been a decrease following changes to the management of equinus gait. These changes were replacing observational with three-dimensional gait analysis, replacing single level with multilevel surgery, and replacing gastrocsoleus lengthening with gastrocnemius recession. Of 464 children and adolescents with spastic diplegia who underwent three-dimensional gait analysis, 27 had severe crouch gait. Seventeen of these had been managed by isolated lengthening of the gastrocsoleus. Following changes in the management of equinus gait, the prevalence of severe crouch gait decreased from 25% and stabilised at a significantly lower rate, fluctuating between 0% and 4% annually (p < 0.001).

We conclude that severe crouch gait in this population was precipitated by isolated lengthening of the gastrocsoleus. These findings may be relevant to other surgical populations, as severe crouch gait may be a useful way to monitor the quality of the surgical management of abnormal gait in children with cerebral palsy and spastic diplegia.

We present a systematic review of the results of the Ponseti method of management for congenital talipes equinovarus (CTEV). Our aims were to assess the method, the effects of modifications to the original method, and compare it with other similar methods of treatment. We found 308 relevant citations in the English literature up to 31 May 2010, of which 74 full-text articles met our inclusion criteria. Our results showed that the Ponseti method provides excellent results with an initial correction rate of around 90% in idiopathic feet. Non-compliance with bracing is the most common cause of relapse. The current best practice for the treatment of CTEV is the original Ponseti method, with minimal adjustments being hyperabduction of the foot in the final cast and the need for longer-term bracing up to four years. Larger comparative studies will be required if other methods are to be recommended.

We have reviewed the literature to establish the role of lateral retinacular release in the management of disorders of the extensor apparatus of the knee. The scientific evidence for intervention is explored and reports on outcome are discussed.

We reviewed the results of a selective à la carte soft-tissue release operation for recurrent or residual deformity after initial conservative treatment for idiopathic clubfoot by the Ponseti method. Recurrent or residual deformity occurred in 13 (19 feet) of 33 patients (48 feet; 40%). The mean age at surgery was 2.3 years (1.3 to 4) and the mean follow-up was 3.6 years (2 to 5.3). The mean Pirani score had improved from 2.8 to 1.1 points, and the clinical and radiological results were satisfactory in all patients. However, six of the 13 patients (9 of 19 feet) had required further surgery in the form of tibial derotation osteotomy, split anterior tibialis tendon transfer, split posterior tibialis transfer or a combination of these for recurrent deformity.

We concluded that selective soft-tissue release can provide satisfactory early results after failure of initial treatment of clubfoot by the Ponseti method, but long-term follow-up to skeletal maturity will be necessary.

Our aim in this retrospective study of 52 children with spastic hemiplegia was to determine the factors which affected the amount of residual pelvic rotation after single-event multilevel surgery.

The patients were divided into two groups, those who had undergone femoral derotation osteotomy and those who had not. Pelvic rotation improved significantly after surgery in the femoral osteotomy group (p < 0.001) but not in the non-femoral osteotomy group. Multiple regressions identified the following three independent variables, which significantly affected residual pelvic rotation: the performance of femoral derotation osteotomy (p = 0.049), the pre-operative pelvic rotation (p = 0.003) and the post-operative internal rotation of the hip (p = 0.001).

We concluded that there is a decrease in the amount of pelvic rotation after single-event multilevel surgery with femoral derotation osteotomy. However, some residual rotation may persist when patients have severe rotation before surgery.

We describe our experience with the ‘four-in-one’ procedure for habitual dislocation of the patella in five children (six knees). All the patients presented with severe generalised ligamentous laxity and aplasia of the trochlear groove. All had a lateral release, proximal ‘tube’ realignment of the patella, semitendinosus tenodesis and transfer of the patellar tendon. The mean age at the time of the operation was 6.1 years (4.9 to 6.9), and the patients were followed up for a mean of 54.5 months (31 to 66). The clinical results were evaluated using the Kujala score.

There has been no recurrence of dislocation. All the patients have returned to full activities and the parents and children were satisfied with the clinical results. The mean Kujala score was 95.3 (88 to 98). Two patients had marginal skin necrosis which healed after debridement and secondary closure. These early results in this small group have shown that the ‘four-in-one’ procedure is effective in the treatment of obligatory dislocation of the patella in children with severe ligamentous laxity and trochlear aplasia.

The rotational alignment of the tibia is an unresolved issue in knee replacement. A poor functional outcome may be due to malrotation of the tibial component. Our aim was to find a reliable method for positioning the tibial component in knee replacement.

CT scans of 19 knees were reconstructed in three dimensions and orientated vertically. An axial plane was identified 20 mm below the tibial spines. The centre of each tibial condyle was calculated from ten points taken round the condylar cortex. The tibial tubercle centre was also generated as the centre of the circle which best fitted eight points on the outside of the tubercle in an axial plane at the level of its most prominent point.

The derived points were identified by three observers with errors of 0.6 mm to 1 mm. The medial and lateral tibial centres were constant features (radius 24 mm (sd 3), and 22 mm (sd 3), respectively). An anatomical axis was created perpendicular to the line joining these two points. The tubercle centre was found to be 20 mm (sd 7) lateral to the centre of the medial tibial condyle. Compared with this axis, an axis perpendicular to the posterior condylar axis was internally rotated by 6° (sd 3). An axis based on the tibial tubercle and the tibial spines was also internally rotated by 5° (sd 10).

Alignment of the knee when based on this anatomical axis was more reliable than either the posterior surfaces or any axis involving the tubercle which was the least reliable landmark in the region.

Excessive foot pronation has been considered to be related to anterior knee pain. We undertook a prospective study to test the hypothesis that exertional anterior knee pain is related to the static and dynamic parameters of foot pronation. Two weeks before beginning basic training lasting for 14 weeks, 473 infantry recruits were enrolled into the study and underwent two-dimensional measurement of their subtalar joint displacement angle during walking on a treadmill.

Of the 405 soldiers who finished the training 61 (15%) developed exertional anterior knee pain. No consistent association was found between the incidence of anterior knee pain and any of the parameters of foot pronation. While a statistically significant association was found between anterior knee pain and pronation velocity (left foot, p = 0.05; right foot, p = 0.007), the relationship was contradictory for the right and left foot. Our study does not support the hypothesis that anterior knee pain is related to excessive foot pronation.

We retrospectively reviewed the operative treatment carried out between 1988 and 1994 of eight patients with habitual patellar dislocation. In four the condition was bilateral. All patients had recurrent dislocation with severe functional disability. The surgical technique involved distal advancement of the patella by complete mobilisation of the patellar tendon, lateral release and advancement of vastus medialis obliquus. The long-term results were assessed radiologically, clinically and functionally using the Lysholm knee score, by an independent observer.

The mean age at operation was 10.3 years (7 to 14) with a mean follow-up of 13.5 years (11 to 16). One patient required revision. At the latest follow-up, all patellae were stable and knees functional with a mean Lysholm knee score of 98 points (95 to 100). In those aged younger than ten years at operation there was a statistically significant improvement in the sulcus angle at the latest follow-up (Student’s t-test, p = 0.001). Two patients developed asymptomatic patella infera as a late complication.

This technique offers a satisfactory treatment for the immature patient presenting with habitual patellar dislocation associated with patella alta. If performed early, we believe that remodelling of the shallow trochlea may occur, adding intrinsic patellofemoral stability.

Genu varum in the achondroplastic patient has a complex and multifactorial aetiology. There is little mention in the literature of the role of fibular overgrowth. Using the ratio of fibular to tibial length as a measurement of possible fibular overgrowth, we have related it to the development of genu varum. Full-length standing anteroposterior radiographs of 53 patients with achondroplasia were analysed. There were 30 skeletally-immature and 23 skeletally-mature patients. Regression analysis was performed in order to determine if there was a causal relationship between fibular overgrowth and the various indices of alignment of the lower limb.

Analysis showed that the fibular to tibial length ratio had a significant correlation with the medial proximal tibial angle and the mechanical axial deviation in the skeletally-immature group. We conclude that there is a significant relationship between fibular overgrowth and the development of genu varum in the skeletally-immature achondroplastic patient.

Chronic patellofemoral instability can be a disabling condition. Management of patients with this condition has improved owing to our increased knowledge of the functional anatomy of the patellofemoral joint. Accurate assessment of the underlying pathology in the unstable joint enables the formulation of appropriate treatment. The surgical technique employed in patients for whom non-operative management has failed should address the diagnosed abnormality. We have reviewed the literature on the stabilising features of the patellofemoral joint, the recommended investigations and the appropriate forms of treatment.

A percutaneous supramalleolar osteotomy with multiple drill holes and closed osteoclasis was used to correct rotational deformities of the tibia in patients with cerebral palsy. The technique is described and the results in 247 limbs (160 patients) are reported. The mean age at the time of surgery was 10.7 years (4 to 20). The radiographs were analysed for time to union, loss of correction, and angulation at the site of the osteotomy.

Bone healing was obtained in all patients except one in a mean period of seven weeks (5 to 12). Malunion after loss of reduction at the site of the osteotomy developed in one tibia.

Percutaneous supramalleolar osteotomy of the tibia is a safe and simple surgical procedure.