Background. Disruption of the normal relationship between the proximal tibia and fibula is seen in a number of different conditions such as skeletal dysplasias and post-infective deformity, as well as the consequence of lengthening procedures. Radiographic indices for the tibio-fibular relationship at the ankle have been described, but no similar measures have been reported for the proximal articulation. Aim. The purpose of this study was to investigate the normal radiographic relationship between the proximal tibia and fibula in children to determine the normal range and variation. Methods. Our radiology database was used to identify a sample of 500 normal anteroposterior radiographs of paediatric knees. All radiographs were reviewed by a single observer. The distance from the corner of the lateral tibial plateau to both the proximal tibial (PT) and fibular physes (PF) were measured, and a ratio of the two calculated (PF/PT). The process was repeated with a sample of 100 radiographs by the same observer, and a second independent observer in order to calculate intra-and inter-observer reliability. Results. The age range of patients in this study was 4–16 years, with mean age 12.7. The mean PF/PT ratio was 1.7 (standard deviation 0.2, range 1.3–2.0). Intra-observer reliability was 100% and inter-observer reliability was 97.8%. Conclusion. The results of this study demonstrate that in the normal paediatric knee, there is a consistent relationship between the position of the proximal tibial and fibular physes, with a small range of variation. The PF/PT ratio is a simple and reliable way of assessing the relationship between the proximal tibia and fibula in children, using a standard anteroposterior radiograph. This ratio could be very useful in the diagnosis and planning of surgical management of a number of different causes of tibial and fibular deformities in children

Summary. Revision TKA using CCK prosthesis showed comparable outcome to PS prosthesis in clinical and radiological results. Introduction. In revision total knee arthroplasty (TKA), the goal should be to obtain good motion, function and most importantly stability. The stability depends on remaining soft tissue and implant design. The more the ligaments retain function, the less the implant constraint is needed to achieve stability. With increased constraint, the transfer of joint reaction forces to implant-bone interface may lead to mechanical loosening of the implant. Constrained condylar knee (CCK) prosthesis provides more constraint compared with posterior stabilized (PS) prosthesis. The purpose of this study was to compare the clinical, radiological outcome and survivorship of CCK and PS prosthesis in revision TKA. Materials and Methods. One hundred and twenty-one consecutive revision TKAs using CCK (79 knees) and PS (42 knees) were included. The mean follow-up period was 63.2 months for CCK and 64.8 months for PS. The mean age was 69.5 years and 70.6 years in CCK and PS, respectively. Range of motion (ROM), American Knee Society (AKS) score, Hospital for Special Surgery (HSS) score, complications and failure rate were assessed. Radiographic measurements included tibiofemoral angle and radiolucent lines. The Kaplan-Meier survivorship analysis was performed with an end point of re-revision surgery for any reason and compared between CCK and PS using the Log-rank test. Results. The mean range of motion improved from 97.5° to 115.9° in PS, from 89.5° to 110.1° in CCK. The mean Knee Society knee and functional scores improved from 47.6 and 36.4 to 89.7 and 66.1 with PS, from 53.5 and 41.7 to 79.2 and 66.8 with CCK. The mean Hospital for Special Surgery knee score also improved from 57 to 76.9 and 59.7 to 77.6, respectively. The complication rate was 7.5% (4 cases; 3 recurred infections, 1 instability) in PS and 10.3% (7 cases; 4 recurred infections, 1 periprosthetic fracture, 2 stem tip pains) in CCK. The Kaplan–Meier survivorship analysis revealed that ten year survival of the components was 85.4% for PS and 80.0% for CCK. In all aspects, there were no statistical difference (a p-value of more than 0.05) between PS and CCK. Conclusion. Revision TKA using CCK prosthesis showed comparable outcome to PS prosthesis in clinical and radiological results. CCK prosthesis is a reliable and successful option for prosthesis selection in revision TKA when PS prosthesis is not enough for management of instability

Cam type femoroacetabular impingement (FAI) is due to an aspheric femoral head, which is best quantified by the alpha angle described on MRI and CT-scan. Radiographic measurement of the alpha angle is not well codified and studies from the literature cannot conclude on the best view to measure it. Most authors also describe a mixed type FAI which associates an aspheric femoral head with an excessive anterior acetabular coverage of the femoral head. Anterior center edge (ACE) angle has been described on the false profile view to measure anterior acetabular coverage in hip dysplasia and has never been evaluated in FAI. In this study, we developed a new lateral hip view which associates a lateral view of the femoral neck and a false profile view of the acétabulum, which we called profile view in impingement position (PVIP). Twenty six patients operated for FAI had CT-scan, the PVIP and the false profile view of one or two hips according to pain. A control group of 19 patients who did not suffer from the hip had the PVIP. Alpha angles were measured twice on 17 CT scan of FAI patients by two observers and compared with the alpha angles measured on the corresponding hip PVIP by a correlation analysis. Alpha angles were measured twice on 45 PVIP in FAI patient and on 19 PVIP in the control group by three observers. ACE angles were measured once on 15 PVIP and on 15 false profile views. Means were compared by two tail paired t-tests, intra- and inter-observer reliability were measured by intraclass correlation coefficient. Mean alpha angle on CT scan was 65.8° and 65.6° for observers 1 and 2 respectively (p>0.05). It was 63.6° and 64.3° on the PVIP (p>0.05). No significant difference was found between CT scan and radiographic measurements, and Pearson's correlation coefficients were good at 0.74 and 0.8. ICC was 0.86 for inter-rater reliability, and 0.91 for intra-rater reliability for CT-scan alpha angle measures. ICC for PVIP measures varied from 0.82 to 0.9 for intra-rater reliability and from 0.6 to 0.9 for inter-rater reliability. Mean alpha angle measured on PVIP in FAI patients was 63.3° and was 44.9° in control subjects and the difference was significant (p<0.001) for the three observers. None of the FAI patients and 88% of the control subjects had an alpha angle < 50°. Mean ACE angle was 26.8° on PVIP and 32.8° on the false profile view, the difference was significant (p=0.015), and the Pearson's correlation coefficient was moderate (r=0.58). The PVIP is a reliable radiographic view to measure the alpha angle. It allows a good quantification of the alpha angle comparable to CT-scan measurements and permits to differentiate patients from control subjects. PVIP is not a good view to quantify anterior edge angle probably because of acetabular retroversion due to the hip flexion needed in this view. Mean ACE angle measured on the false profile view in FAI patient was comparable to ACE angle in general population reported in the literature

We prospectively assessed the diagnostic accuracy of the gravity stress test and clinical findings to evaluate the stability of the ankle mortise in patients with supination–external rotation-type fractures of the lateral malleolus without widening of the medial clear space. The cohort included 79 patients with a mean age of 44 years (16 to 82). Two surgeons assessed medial tenderness, swelling and ecchymosis and performed the external rotation (ER) stress test (a reference standard). A diagnostic radiographer performed the gravity stress test.

For the gravity stress test, the positive likelihood ratio (LR) was 5.80 with a 95% confidence interval (CI) of 2.75 to 12.27, and the negative LR was 0.15 (95% CI 0.07 to 0.35), suggesting a moderate change from the pre-test probability. Medial tenderness, both alone and in combination with swelling and/or ecchymosis, indicated a small change (positive LR, 2.74 to 3.25; negative LR, 0.38 to 0.47), whereas swelling and ecchymosis indicated only minimal changes (positive LR, 1.41 to 1.65; negative LR, 0.38 to 0.47).

In conclusion, when gravity stress test results are in agreement with clinical findings, the result is likely to predict stability of the ankle mortise with an accuracy equivalent to ER stress test results. When clinical examination suggests a medial-side injury, however, the gravity stress test may give a false negative result.

Cite this article: Bone Joint J 2015; 97-B:1126–31.

Objectives

The biomembrane (induced membrane) formed around polymethylmethacrylate (PMMA) spacers has value in clinical applications for bone defect reconstruction. Few studies have evaluated its cellular, molecular or stem cell features. Our objective was to characterise induced membrane morphology, molecular features and osteogenic stem cell characteristics.

Fracture-dislocations of the tarsometatarsal (Lisfranc) joints are frequently overlooked or misdiagnosed at initial presentation. This is a comparative cohort study over a period of five years comparing primary open reduction and internal fixation in 22 patients (23 feet) with secondary corrective arthrodesis in 22 patients (22 feet) who presented with painful malunion at a mean of 22 months (1.5 to 45) after injury. In the first group primary treatment by open reduction and internal fixation for eight weeks with Kirschner-wires or screws was undertaken, in the second group treatment was by secondary corrective arthrodesis. There was one deep infection in the first group. In the delayed group there was one complete and one partial nonunion.

In each group 20 patients were available for follow-up at a mean of 36 months (24 to 89) after operation. The mean American Orthopaedic Foot and Ankle Society midfoot score was 81.4 (62 to 100) after primary treatment and 71.8 (35 to 88) after corrective arthrodesis (t-test; p = 0.031).

We conclude that primary treatment by open reduction and internal fixation of tarsometatarsal fracture-dislocations leads to improved functional results, earlier return to work and greater patient satisfaction than secondary corrective arthrodesis, which remains a useful salvage procedure providing significant relief of pain and improvement in function.