A comparison of the semiflexed (MTP) view with the standing extended view (SEV) in the radiographic assessment of knee osteoarthritis in a busy routine X-ray department

OBJECTIVE

To compare the reproducibility of the standing extended view (SEV) (also known as the standing anteroposterior view) with the semiflexed, postero-anterior view [the 'metatarsophalangeal' (MTP)] view for assessing joint space width (JSW) and osteophytes in osteoarthritis of the knee when used in a busy routine X-ray department.

METHODS

Forty-seven patients (24 men) had both SEV and MTP views taken on the same day in a busy National Health Service radiography department. Repeat views were taken as entirely separate procedures some time over the following 2 weeks, in the same department and with no special arrangements for the selection of radiographers, time of day, or X-ray machine. The first 24 patients had second views in the SEV position whilst the remaining 23 had second MTP views. Radiographs were read independently by two experienced observers who measured JSW with a transparent ruler to the nearest 0.5 mm at the narrowest point in both medial and lateral compartments of the tibiofemoral joint in both knees. Osteophytes were graded 0-2 according to a standard atlas. Ten SEV and 10 MTP radiographs selected randomly were re-read by one observer.

RESULTS

Mean (95% confidence interval) JSW in the medial compartment measured on SEV radiographs was 3.54 mm (3.08, 3.99) and on MTP radiographs it was 2.80 mm (2.37, 3.23); in the lateral compartment it was 6.04 mm (5.71, 6.37) when measured on SEV radiographs and 5.47 mm (5.09, 5.85) on MTP radiographs. The estimated variances for the medial compartment were 2.0 mm2 for SEV and 0.2 mm2 for MTP (P < 0.001) and for the lateral compartment 1.4 mm2 for SEV and 0.5 mm2 for MTP (P < 0.001). The proportion of radiographs for which there was disagreement between observers regarding osteophyte grade was not statistically different between SEV and MTP views (SEV, medial 40%, lateral 44%; MTP, medial 39%, lateral 39%).

CONCLUSIONS

Even when radiographs are taken in a busy National Health Service radiography department, measurement of JSW from the MTP view is more reproducible than from the SEV view, the MTP view gives a slightly lower measurement of JSW, and there is no advantage in using either view in recording osteophyte grade. We recommend the wider adoption of the MTP method.

[Hypophosphatemic oncogenic osteomalacia]

The first case of oncogen osteomalacia in Hungary is reported, to draw the attention of the medical profession to it and to present the new data about its pathomechanism. Pathological hip fracture caused by hypophosphataemic osteomalacia due to isolated renal phosphate wasting was found in a previously healthy 19 years old sportsman. In spite of daily 1.5 micrograms calcitriol treatment and phosphate supplementation, hypophosphataemia persisted for 13 years and he needed regular indometacin medication for his bone pain. During that time an 1.5 cm gingival tumour was found and radically removed. The serum phosphate level returned to normal in a few hours after the operation (preoperative 0.51, after 2, 4 and 8 hours 0.61, 0.68 and 0.79 mmol/l respectively), and remained normal without calcitriol. The histological examination showed epulis with fibroblast and vascular cell proliferation, which has never been previously reported in connection with oncogenic osteomalacia. The pain resolved after 3 months and the bone density became normal in one year. Oncogenic osteomalacia must be considered in every case presenting with atypical hypophosphataemic osteomalacia. Careful dental examination is needed also in the course of search for the underlying tumour. Every tumour-like growth, even the common epulis, has to be operated radically and serum phosphate monitored in the postoperative period in all such cases.

Hereditary disorders mimicking and/or causing premature osteoarthritis

Osteoarthritis is the most common joint disease, causing considerable disability and impairment of quality of life. Hereditary osteochondrodysplasias and some inborn errors of metabolism may mimic or cause premature osteoarthritis. Osteochondrodysplasias usually cause joint deformities, such as coxa vara or genu varum, which can cause abnormal biomechanics. In most of these disorders, the articular cartilage is originally defective as a result of genetically determined collagen or matrix protein abnormalities, or the deposition of mucopolysaccharides. In the case of inborn errors of metabolism, the pathological process affects healthy articular structures, causing secondary osteoarthritis. In alkaptonuria, the pathological deposition of polymerized homogenistic acid causes defective changes in cartilage, articular capsule and tendons. In Wilson's disease, the premature osteoarthritis might be caused by the copper deposition. It is worth paying attention to these rare disorders, even when they are mild or incomplete, because early diagnosis can lead to prevention and effective treatment. In addition, research is discovering the specific gene defects and molecular abnormalities that are responsible for disease expression. This may in turn lead to opportunities for prenatal diagnosis; thus, genetic counselling and gene replacement therapy may be a realistic possibility in the near future.

Familial adult onset X-linked hypophosphataemic osteomalacia (report of a family; clinical and experimental studies)

From four patients (a great-grandmother, grandmother, her daughter and her grandson) suffering from a very severe form of familial X-linked hypophosphataemic osteomalacia (XLH), belonging to a 23-number-kindred of five generations, the youngest patient a 24-year-old man with an adult onset XLH was treated with phosphate and calcitriol for two years. Phosphate was given in increasing doses (500-6000 mg elemental phosphate) by mouth for a relatively short-term period and calcitriol in high doses per os combined with intermittent intravenous administration. Long-term treatment consisted of daily three grams of phosphate and 1.25 micrograms calcitriol by mouth combined with daily 2 micrograms calcitriol intravenously for one week every month. Dramatic clinical improvement occurred accompanied with definite radiological and scintigraphical changes. Serum phosphate increased from 0.525 +/- 0.478 mmol/l to 1.054 +/- 0.041 mmol/l (p < 0.001) in response to 3000 mg phosphate. A close correlation (r = 0.69) was found between serum phosphate and urinary phosphate excretions (p < 0.001) and an inverse correlation (r = -0.31) was found between serum phosphate and tubular reabsorption of phosphate (p < 0.01). Serum and urinary calcium values, parathormone as well as renal functions did not change. Administration of high doses of phosphate seemed to be an effective and probably safe form of treatment in XLH provided that development of hyperparathyroidism is prevented by the coadministration of high doses of calcitriol.

Non-pharmacological therapies in osteoarthritis

Non-pharmacological therapies are very important in osteoarthritis. Each form of this treatment should be individually devised, taking into account the anatomical distribution, the phase and the progression rate of the disease. Indications, contraindications, dosage and precautions are as important in non-pharmacological therapy as they are in drug treatment. Therapeutic exercises decrease pain, increase muscle strength and range of joint motion as well as improve endurance and aerobic capacity. Exercise programmes should be designed, conducted and regularly supervised by professionally trained physiotherapists. Weight reduction is of proven benefit in obese patients with osteoarthritis of the knee. Walking aids, crutches, shoe insoles, braces and patellar taping are useful tools in some form of osteoarthritis. Patient education and the management of the psychosocial consequences are priority tasks. Therapeutic heat and cold, electrotherapy, ultrasound, acupuncture, hydrotherapy and spa treatment are widely used, although the effects and benefits have not been fully established. Non-pharmacological therapies should undergo rigorous randomized controlled trials in a similar manner to pharmacological studies.

[Adult-onset sex-linked familial hypophosphatemic osteomalacia]

Three patients (a grandmother, her daughter and her grandson) belonging to a 23-number-kindred of five generations suffered from adult-onset, X-linked, familiar hypophosphataemic osteomalacia. According to the familiar anecdotes the great-grandmother also had the same disease. The clinical diagnosis was documented by X-ray pictures, scintigraphic and bone histological results, the laboratory diagnosis was proven by blood and urine analyses examined after phosphate loading. The youngest, 24-year-old patient was treated with daily 3 g phosphate and high doses of calcitriol for 2 years. As a new feature of our therapy, per os treatment with 1.25 micrograms calcitriol was supplemented by daily 2-4 micrograms iv. bolus calcitriol for one week every month. The osteomalacia, causing serious symptoms and complaints, healed. Our treatment seemed to be safe, as renal functions, serum total and ionized calcium and PTH levels (including midnight values) remained in normal range. On the basis of our results this disease can be treated by administration of high doses of phosphate, provided that development of hyperparathyroidism is prevented by the coadministration of high doses of calcitriol.

Diagnosis of osteoarthritis. Guidelines and current pitfalls

Diagnostic and classification guidelines for osteoarthritis based on clinical and radiographic signs for the most frequently involved joints (knee, hip and hand) have been developed by the American College of Rheumatology. Excellent, new 'high tech' biochemical and imaging methods and guidelines for clinical evaluation of the condition and its therapy have recently been developed and validated. Accordingly, we have consistent and reliable methods for assessing the established condition, but they provide little help in making an early and correct diagnosis for the different forms of osteoarthritis. Both the diagnostic process and the differential diagnosis consist of careful history taking and detailed analysis of the complaints (especially pain), with proper physical examination including a search for the source of pain and tenderness. Not all deformities and pain in and around the joints are signs and symptoms of osteoarthritis, even if the patient is of 'osteoarthritis age' and the joint shows 'osteoarthritis signs' on the x-ray. On the other hand, even if the underlying disease is osteoarthritis, the symptoms and signs may be due to disorders secondary to the basic disease (e.g. enthesopathy or tendinopathy) and the patient's complaints can be helped more easily by physiotherapy and local injections. The course of the disease and close follow-up yield diagnostic clues in cases where the cross-sectional diagnostic measures fail to provide them. Analysis of serum, joint fluid and x-ray films can be of diagnostic value, and other imaging methods (ultrasound, radioisotope scanning, computerised tomography, magnetic resonance imaging, arthroscopy) are also useful tools. Differential diagnosis is not only of theoretical value; misdiagnosis of osteoarthritis leads to either omitted or unnecessary treatment, and causes psychological stress to the patient.

Quantitative serial assessment of patellofemoral joint osteoarthritis from lateral knee radiographs

This study describes a new method for patellofemoral joint space measurement on lateral knee radiographs of patients from a case register of knee osteoarthritis (OA). The reproducibility of the technique was tested on 31 lateral radiographs and the validity, accuracy and sensitivity to change were examined in 82 patients (52 female, 30 male, mean age 66.5 years) with anteroposterior and lateral knee radiographs at two time points 3 years apart. The measurements were compared with visual assessments of joint space narrowing, subchondral sclerosis and osteophyte grade previously recorded by an independent observer. The degree of knee flexion was also recorded. The 'narrowest' joint space measurement was found to be a simple reproducible technique (coefficient of variation 8.5%). A significant correlation was found between the measured joint space and knee flexion. The reduction in measured joint space over 3 years was not significant (P = 0.067) but the group contained a large number of disease-free patellofemoral joints. The joint spaces were, however, significantly smaller in the presence of patellofemoral OA with or without tibiofemoral OA suggesting the technique to be valid. The measurements were also significantly smaller in the presence of a visual assessment of joint space narrowing and subchondral sclerosis. The mean measured joint space increased in the presence of severe osteophyte formation. This suggests that patellofemoral joint space measurement from lateral radiographs provides a sensitive and quantitative assessment of progression in OA at this articulation.

Radio-anatomic position for the lateral radiographic view of the human patello-femoral joint

Recent clinical and epidemiological studies have emphasised the importance of the patello-femoral joint (P-FJ) in osteoarthritis. X-ray examination of this joint for joint space width (JSW) assessment using the standard medio-lateral view is difficult. In 26 femora, the mean angle of inclination between the medial and lateral condyles measured at their inferior and anterior surfaces, relative to a line passing between the medial and lateral femoral epicondyles, was used to define the optimum alignment of the x-ray tube. The results showed that for medio-lateral radiography of the P-FJ, the central ray of the x-ray beam should be directed cranially, in a upward projection by 5 degrees and then anteriorly by 4 degrees, resulting in superimposition of the inferior and anterior condylar surfaces respectively. The value of these angles was confirmed by radiographs of the 26 femora and 10 post mortem joints. The margins for joint space width measurement were identified by embedding lead balls, within the cartilage of the cadaveric knees, and were defined as the median vertical ridge of the patella and the middle of the patella groove on the femur.