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The Bone & Joint Journal
Vol. 104-B, Issue 1 | Pages 103 - 111
1 Jan 2022
Li J Hu Z Qian Z Tang Z Qiu Y Zhu Z Liu Z

Aims. The outcome following the development of neurological complications after corrective surgery for scoliosis varies from full recovery to a permanent deficit. This study aimed to assess the prognosis and recovery of major neurological deficits in these patients, and to determine the risk factors for non-recovery, at a minimum follow-up of two years. Methods. A major neurological deficit was identified in 65 of 8,870 patients who underwent corrective surgery for scoliosis, including eight with complete paraplegia and 57 with incomplete paraplegia. There were 23 male and 42 female patients. Their mean age was 25.0 years (SD 16.3). The aetiology of the scoliosis was idiopathic (n = 6), congenital (n = 23), neuromuscular (n = 11), neurofibromatosis type 1 (n = 6), and others (n = 19). Neurological function was determined by the American Spinal Injury Association (ASIA) impairment scale at a mean follow-up of 45.4 months (SD 17.2). the patients were divided into those with recovery and those with no recovery according to the ASIA scale during follow-up. Results. The incidence of major deficit was 0.73%. At six-month follow-up, 39 patients (60%) had complete recovery and ten (15.4%) had incomplete recovery; these percentages improved to 70.8% (46) and 16.9% (11) at follow-up of two years, respectively. Eight patients showed no recovery at the final follow-up. The cause of injury was mechanical in 39 patients and ischaemic in five. For 11 patients with misplaced implants and haematoma formation, nine had complete recovery. Fisher’s exact test showed a significant difference in the aetiology of the scoliosis (p = 0.007) and preoperative deficit (p = 0.016) between the recovery and non-recovery groups. A preoperative deficit was found to be significantly associated with non-recovery (odds ratio 8.5 (95% confidence interval 1.676 to 43.109); p = 0.010) in a multivariate regression model. Conclusion. For patients with scoliosis who develop a major neurological deficit after corrective surgery, recovery (complete and incomplete) can be expected in 87.7%. The first three to six months is the time window for recovery. In patients with misplaced implants and haematoma formation, the prognosis is satisfactory with appropriate early intervention. Patients with a preoperative neurological deficit are at a significant risk of having a permanent deficit. Cite this article: Bone Joint J 2022;104-B(1):103–111


The Bone & Joint Journal
Vol. 101-B, Issue 10 | Pages 1379 - 1384
1 Oct 2019
Park J Park S Lee C

Aims. This study aimed to evaluate the incidence and prognosis of patients with spinal metastasis as the initial manifestation of malignancy (SM-IMM). Patients and Methods. We retrospectively reviewed the electronic medical records of 338 patients who underwent surgical treatment for metastatic spinal disease. The enrolled patients were divided into two groups. The SM-IMM group included patients with no history of malignancy whose site of primary malignancy was diagnosed after the identification of spinal metastasis. The other group included patients with a history of treatment for primary malignancy who then developed spinal metastasis (SM-DTM). The incidence of SM-IMM by site of primary malignancy was calculated. The difference between prognoses after surgical treatment for SM-IMM and SM-DTM was established. Results. The median follow-up period was 11.5 months (interquartile range (IQR) 3.2 to 13.4) after surgical treatment. During the follow-up period, 264 patients died; 74 patients survived. The SM-IMM group consisted of 94 patients (27.8%). The site of primary malignancy in the SM-IMM group was lung in 35/103 patients (34.0%), liver in 8/45 patients (17.8%), kidney in 10/33 patients (30.3%), colorectum in 3/29 patients (10.3%), breast in 3/22 patients (13.6%), prostate in 3/10 patients (30%), thyroid in 4/8 patients (50%), and ‘other’ in 28/88 patients (31.8%). On Kaplan–Meier survival analysis, the SM-IMM group showed a significantly longer survival than the SM-DTM group (p = 0.013). The mean survival time was 23.0 months (95% confidence interval (CI) 15.5 to 30.5) in the SM-IMM group and 15.5 months (95% CI 11.8 to 19.2) in the SM-DTM group. Conclusion. Of the 338 enrolled patients who underwent surgical treatment for spinal metastasis, 94 patients (27.8%) underwent surgical treatment for SM-IMM. The SM-IMM group had an acceptable prognosis with surgical treatment. Cite this article: Bone Joint J 2019;101-B:1379–1384


The Journal of Bone & Joint Surgery British Volume
Vol. 60-B, Issue 2 | Pages 189 - 194
1 May 1978
Dickens D Menelaus M

Seventy children who had suffered from Perthes' disease were reviewed clinically and radiologically three to eight years from the onset of the condition in order to determine retrospectively the most satisfactory method of assessing the prognosis and the correlation between the clinical and radiological result. In younger children the femoral head was more likely to be spherical at the conclusion of the pathological process but not necessarily of normal proportions nor normally covered by the acetabulum. The prognosis was significantly poorer for girls than for boys. Clinical factors were not an aid to prognosis in the individual cases, but overall there was a close correlation between the clinical and the radiological end-results. The most reliable radiological factors indicating the prognosis were the extent of uncovering of the femoral head, the Catterall grouping, the presence of calcification lateral to the outer limit of the acetabulum and lateral displacement of the femoral head, as measured by comparing the head to tear-drop distances on each side


The Bone & Joint Journal
Vol. 105-B, Issue 2 | Pages 109 - 111
1 Feb 2023
Karjalainen T Buchbinder R

Tennis elbow (lateral epicondylitis or lateral elbow tendinopathy) is a self-limiting condition in most patients. Surgery is often offered to patients who fail to improve with conservative treatment. However, there is no evidence to support the superiority of surgery over continued nonoperative care or no treatment. New evidence also suggests that the prognosis of tennis elbow is not influenced by the duration of symptoms, and that there is a 50% probability of recovery every three to four months. This finding challenges the belief that failed nonoperative care is an indication for surgery. In this annotation, we discuss the clinical and research implications of the benign clinical course of tennis elbow. Cite this article: Bone Joint J 2023;105-B(2):109–111


The Journal of Bone & Joint Surgery British Volume
Vol. 63-B, Issue 3 | Pages 404 - 407
1 Aug 1981
Rorabeck C Harris W

The clinical results in a series of 131 patients with 134 brachial plexus injuries were analysed to determine the factors affecting prognosis. Isolated injuries to the upper trunk had the best prognosis, but the prognoses of isolated injuries to the cords, upper roots and lower trunk were not as good. Complete injuries of the plexus had the worst prognosis. Pain which persisted for more than six months was a bad prognostic sign for neurological recovery regardless of the location of the lesion. Horner's syndrome was not always accompanied by a bad prognosis. Operation did not affect the prognosis except in open lacerations. A pseudomeningocele detected by myelography usually precluded recovery in the root at the level of the pseudomeningocele


The Bone & Joint Journal
Vol. 105-B, Issue 12 | Pages 1244 - 1251
1 Dec 2023
Plastow R Raj RD Fontalis A Haddad FS

Injuries to the quadriceps muscle group are common in athletes performing high-speed running and kicking sports. The complex anatomy of the rectus femoris puts it at greatest risk of injury. There is variability in prognosis in the literature, with reinjury rates as high as 67% in the severe graded proximal tear. Studies have highlighted that athletes can reinjure after nonoperative management, and some benefit may be derived from surgical repair to restore function and return to sport (RTS). This injury is potentially career-threatening in the elite-level athlete, and we aim to highlight the key recent literature on interventions to restore strength and function to allow early RTS while reducing the risk of injury recurrence. This article reviews the optimal diagnostic strategies and classification of quadriceps injuries. We highlight the unique anatomy of each injury on MRI and the outcomes of both nonoperative and operative treatment, providing an evidence-based management framework for athletes. Cite this article: Bone Joint J 2023;105-B(12):1244–1251


The Bone & Joint Journal
Vol. 104-B, Issue 9 | Pages 1011 - 1016
1 Sep 2022
Acem I van de Sande MAJ

Prediction tools are instruments which are commonly used to estimate the prognosis in oncology and facilitate clinical decision-making in a more personalized manner. Their popularity is shown by the increasing numbers of prediction tools, which have been described in the medical literature. Many of these tools have been shown to be useful in the field of soft-tissue sarcoma of the extremities (eSTS). In this annotation, we aim to provide an overview of the available prediction tools for eSTS, provide an approach for clinicians to evaluate the performance and usefulness of the available tools for their own patients, and discuss their possible applications in the management of patients with an eSTS. Cite this article: Bone Joint J 2022;104-B(9):1011–1016


The Journal of Bone & Joint Surgery British Volume
Vol. 33-B, Issue 2 | Pages 149 - 159
1 May 1951
DoBson J

1. Three hundred and twenty cases of tuberculosis of the hip joint have been analysed and the late results assessed three or more years after discharge from hospital. 2. The primary bone focus involved the acetabulum alone in 39·3 per cent; the acetabulum and femoral head in 34·1 per cent; the head of femur alone in 19·2 per cent, and the femoral neck alone in 7·4 per cent. In 101 cases widespread destruction of the joint had taken place by the time the patient first came under observation. 3. Premature epiphysial fusion round the knee joint of the affected side occurred in 23 per cent of all patients under the age of fifteen years. 4. When hip disease was complicated by multiple foci of active tuberculosis or by secondarily infected abscesses and sinuses, the prognosis was seriously worsened. 5. Significant late deformity occurred in 38·3 per cent of patients discharged with "sound" fibrous ankylosis, and in 60·5 per cent of those with an unstable fibrous ankylosis. 6. Of 187 patients observed for more than three years after discharge from hospital 174 returned to full activity, seven were partly incapacitated and six were totally incapacitated. 7. Analysis of the late results suggests that the prognosis is best when an adequate period of conservative treatment is followed by some form of arthrodesis operation


The Bone & Joint Journal
Vol. 105-B, Issue 6 | Pages 679 - 687
1 Jun 2023
Lou Y Zhao C Cao H Yan B Chen D Jia Q Li L Xiao J

Aims. The aim of this study was to report the long-term prognosis of patients with multiple Langerhans cell histiocytosis (LCH) involving the spine, and to analyze the risk factors for progression-free survival (PFS). Methods. We included 28 patients with multiple LCH involving the spine treated between January 2009 and August 2021. Kaplan-Meier methods were applied to estimate overall survival (OS) and PFS. Univariate Cox regression analysis was used to identify variables associated with PFS. Results. Patients with multiple LCH involving the spine accounted for 15.4% (28/182 cases) of all cases of spinal LCH: their lesions primarily involved the thoracic and lumbar spines. The most common symptom was pain, followed by neurological dysfunction. All patients presented with osteolytic bone destruction, and 23 cases were accompanied by a paravertebral soft-tissue mass. The incidence of vertebra plana was low, whereas the oversleeve-like sign was a more common finding. The alkaline phosphatase was significantly higher in patients with single-system multifocal bone LCH than in patients with multisystem LCH. At final follow-up, one patient had been lost to follow-up, two patients had died, three patients had local recurrence, six patients had distant involvement, and 17 patients were alive with disease. The median PFS and OS were 50.5 months (interquartile range (IQR) 23.5 to 63.1) and 60.5 months (IQR 38.0 to 73.3), respectively. Stage (hazard ratio (HR) 4.324; p < 0.001) and chemotherapy (HR 0.203; p < 0.001) were prognostic factors for PFS. Conclusion. Pain is primarily due to segmental instability of the spine from its destruction by LCH. Chemotherapy can significantly improve PFS, and radiotherapy has achieved good results in local control. The LCH lesions in some patients will continue to progress. It may initially appear as an isolated or single-system LCH, but will gradually involve multiple sites or systems. Therefore, long-term follow-up and timely intervention are important for patients with spinal LCH. Cite this article: Bone Joint J 2023;105-B(6):679–687


The Bone & Joint Journal
Vol. 106-B, Issue 7 | Pages 751 - 758
1 Jul 2024
Yaxier N Zhang Y Song J Ning B

Aims. Given the possible radiation damage and inaccuracy of radiological investigations, particularly in children, ultrasound and superb microvascular imaging (SMI) may offer alternative methods of evaluating new bone formation when limb lengthening is undertaken in paediatric patients. The aim of this study was to assess the use of ultrasound combined with SMI in monitoring new bone formation during limb lengthening in children. Methods. In this retrospective cohort study, ultrasound and radiograph examinations were performed every two weeks in 30 paediatric patients undergoing limb lengthening. Ultrasound was used to monitor new bone formation. The number of vertical vessels and the blood flow resistance index were compared with those from plain radiographs. Results. We categorized the new bone formation into three stages: stage I (early lengthening), in which there was no obvious callus formation on radiographs and ultrasound; stage II (lengthening), in which radiographs showed low-density callus formation with uneven distribution and three sub-stages could be identified on ultrasound: in Ia punctate callus was visible; in IIb there was linear callus formation which was not yet connected and in IIc there was continuous linear callus. In stage III (healing), the bone ends had united, the periosteum was intact, and the callus had disappeared, as confirmed on radiographs, indicating healed bone. A progressive increase in the number of vertical vessels was noted in the early stages, peaking during stages IIb and IIc, followed by a gradual decline (p < 0.001). Delayed healing involved patients with a prolonged stage IIa or those who regressed to stage IIa from stages IIb or IIc during lengthening. Conclusion. We found that the formation of new bone in paediatric patients undergoing limb lengthening could be reliably evaluated using ultrasound when combined with the radiological findings. This combination enabled an improved assessment of the prognosis, and adjustments to the lengthening protocol. While SMI offered additional insights into angiogenesis within the new bone, its role primarily contributed to the understanding of the microvascular environment rather than directly informing adjustments of treatment. Cite this article: Bone Joint J 2024;106-B(7):751–758


The Bone & Joint Journal
Vol. 106-B, Issue 8 | Pages 865 - 870
1 Aug 2024
Broida SE Sullivan MH Rose PS Wenger DE Houdek MT

Aims. Venous tumour thrombus (VTT) is a rare finding in osteosarcoma. Despite the high rate of VTT in osteosarcoma of the pelvis, there are very few descriptions of VTT associated with extrapelvic primary osteosarcoma. We therefore sought to describe the prevalence and presenting features of VTT in osteosarcoma of both the pelvis and the limbs. Methods. Records from a single institution were retrospectively reviewed for 308 patients with osteosarcoma of the pelvis or limb treated between January 2000 and December 2022. Primary lesions were located in an upper limb (n = 40), lower limb (n = 198), or pelvis (n = 70). Preoperative imaging and operative reports were reviewed to identify patients with thrombi in proximity to their primary lesion. Imaging and histopathology were used to determine presence of tumour within the thrombus. Results. Tumours abutted the blood vessels in 131 patients (43%) and encased the vessels in 30 (10%). Any form of venous thrombus was identified in 31 patients (10%). Overall, 21 of these thrombi were determined to be involved with the tumour based on imaging (n = 9) or histopathology (n = 12). The rate of VTT was 25% for pelvic osteosarcoma and 1.7% for limb osteosarcoma. The most common imaging features associated with histopathologically proven VTT were enhancement with contrast (n = 12; 100%), venous enlargement (n = 10; 83%), vessel encasement (n = 8; 66%), and visible intraluminal osteoid matrix (n = 6; 50%). Disease-specific survival (DSS) for patients with VTT was 95% at 12 months (95% CI 0.87 to 1.00), 50% at three years (95% CI 0.31 to 0.80), and 31% at five years (95% CI 0.14 to 0.71). VTT was associated with worse DSS (hazard ratio 2.3 (95% CI 1.11 to 4.84). Conclusion. VTT is rare with osteosarcoma and occurs more commonly in the pelvis than the limbs. Imaging features suggestive of VTT include enhancement with contrast, venous dilation, and vessel encasement. VTT portends a worse prognosis for patients with osteosarcoma, with a similar survivability to metastatic disease. Cite this article: Bone Joint J 2024;106-B(8):865–870


The Bone & Joint Journal
Vol. 105-B, Issue 9 | Pages 1007 - 1012
1 Sep 2023
Hoeritzauer I Paterson M Jamjoom AAB Srikandarajah N Soleiman H Poon MTC Copley PC Graves C MacKay S Duong C Leung AHC Eames N Statham PFX Darwish S Sell PJ Thorpe P Shekhar H Roy H Woodfield J

Aims. Patients with cauda equina syndrome (CES) require emergency imaging and surgical decompression. The severity and type of symptoms may influence the timing of imaging and surgery, and help predict the patient’s prognosis. Categories of CES attempt to group patients for management and prognostication purposes. We aimed in this study to assess the inter-rater reliability of dividing patients with CES into categories to assess whether they can be reliably applied in clinical practice and in research. Methods. A literature review was undertaken to identify published descriptions of categories of CES. A total of 100 real anonymized clinical vignettes of patients diagnosed with CES from the Understanding Cauda Equina Syndrome (UCES) study were reviewed by consultant spinal surgeons, neurosurgical registrars, and medical students. All were provided with published category definitions and asked to decide whether each patient had ‘suspected CES’; ‘early CES’; ‘incomplete CES’; or ‘CES with urinary retention’. Inter-rater agreement was assessed for all categories, for all raters, and for each group of raters using Fleiss’s kappa. Results. Each of the 100 participants were rated by four medical students, five neurosurgical registrars, and four consultant spinal surgeons. No groups achieved reasonable inter-rater agreement for any of the categories. CES with retention versus all other categories had the highest inter-rater agreement (kappa 0.34 (95% confidence interval 0.27 to 0.31); minimal agreement). There was no improvement in inter-rater agreement with clinical experience. Across all categories, registrars agreed with each other most often (kappa 0.41), followed by medical students (kappa 0.39). Consultant spinal surgeons had the lowest inter-rater agreement (kappa 0.17). Conclusion. Inter-rater agreement for categorizing CES is low among clinicians who regularly manage these patients. CES categories should be used with caution in clinical practice and research studies, as groups may be heterogenous and not comparable. Cite this article: Bone Joint J 2023;105-B(9):1007–1012


The Journal of Bone & Joint Surgery British Volume
Vol. 65-B, Issue 5 | Pages 608 - 611
1 Nov 1983
Norris S Watt I

Injury of the neck may result when a motor vehicle is run into from behind; such injury is frequently the cause of prolonged disability and litigation. We report a series of 61 patients with these injuries. A classification, based upon the presenting symptoms and physical signs has been evolved. This classification is shown to be a reliable basis for formulating a prognosis. Factors which adversely affect prognosis include the presence of objective neurological signs, stiffness of the neck, muscle spasm, and pre-existing degenerative spondylosis


The Journal of Bone & Joint Surgery British Volume
Vol. 51-B, Issue 4 | Pages 593 - 603
1 Nov 1969
Gupta SK Helal BH Kiely P

1. Forty-five cases of zoster paralysis, not involving the cranial nerves, are detailed. These include eighteen cases not previously published. Of these eighteen patients, one-third were referred for an orthopaedic opinion. 2. Complete or almost full recovery occurred within a year in two-thirds of the patients. Permanent paralysis occurred in one-sixth of the patients studied. 3. Muscles that failed to recover were mainly or wholly supplied from single segments of the spinal cord; so the prognosis must be guarded in those cases in which such muscles are completely paralysed. 4. Various phenomena occurring in zoster paralysis are discussed


The Journal of Bone & Joint Surgery British Volume
Vol. 91-B, Issue 6 | Pages 784 - 788
1 Jun 2009
Kaya M Wada T Nagoya S Sasaki M Matsumura T Yamashita T

We undertook a prospective study to evaluate the prognostic significance of the serum levels of vascular endothelial growth factor (VEGF) in predicting the survival of patients with osteosarcoma. The levels were measured by an enzyme-linked immunosorbent assay in 15 patients with osteosarcoma before commencing treatment. The patients were divided into two groups, with a high or a low serum VEGF level, and the incidence of metastases and overall survival rate were compared. No significant relationship was observed between the serum VEGF levels and gender, age, the size of the tumour or the response to pre-operative chemotherapy. Patients with a serum VEGF > 1000 pg/ml had significantly worse survival than those with a level < 1000 pg/ml (p = 0.002). The serum VEGF level may be useful in predicting the prognosis for survival in patients with osteosarcoma


The Journal of Bone & Joint Surgery British Volume
Vol. 88-B, Issue 8 | Pages 1071 - 1075
1 Aug 2006
Bacci G Fabbri N Balladelli A Forni C Palmerini E Picci P

Between 1986 and 2002, 42 patients with synchronous multifocal osteosarcoma were treated with two different protocols of neoadjuvant chemotherapy. When feasible, the primary and secondary tumours were excised as a combined procedure. After initial chemotherapy 26 patients were excluded from simultaneous excision of all their secondary bone lesions as their disease was too advanced. In 12 patients only isolated excision of the primary lesion was possible. For 16 patients simultaneous operations were conducted to excise the primary and secondary lesions. This involved two supplementary sites in 15 patients and four additional sites in one patient. Of these, 15 attained remission but 12 relapsed and died (11 within two years). Three patients remained disease-free at five, six and 17 years. The histological response to pre-operative chemotherapy of the primary and secondary lesions was concordant in 13 of the 16 patients who underwent simultaneous operations at more than one site. The prognosis for synchronous multifocal osteosarcoma remains poor despite combined chemotherapy and surgery. The homogeneous histological responses in a large proportion of the primary and secondary lesions implies that synchronous multifocal osteosarcoma tumours are not multicentric in origin, but probably represent bone-to-bone metastases from a single tumour


The Journal of Bone & Joint Surgery British Volume
Vol. 62-B, Issue 2 | Pages 151 - 154
1 May 1980
Thompson S Bentley G

A review was performed of 86 cases of infantile idiopathic scoliosis treated between 1962 and 1979. The single primary curves were classified as resolving, stable, progressive with a low rib--vertebra angle difference (RVAD) and progressive with a high RVAD. Two single primary curves subsequently developed a second curve and 17 were double when first diagnosed. Prognosis was difficult to establish before the age of five years. Only 18 per cent of curves showing progression beyond 50 degrees reached that point before the age of four. Conversely, if a scoliosis of 50 degrees or more was present before the age of four it always progressed. A more favourable outcome was indicated by male sex, a left-sided curve, a low initial curve measurement, an RVAD of less than 20 degrees in the initial radiograph, and the onset of scoliosis in the first year of life


The Journal of Bone & Joint Surgery British Volume
Vol. 80-B, Issue 2 | Pages 310 - 314
1 Mar 1998
Ismail AM Macnicol MF

We compared the prognostic value of the Catterall grouping, the Salter-Thompson grading, the arthrographic shape of the femoral head, and the Herring lateral pillar grouping during the fragmentation stage of Perthes’ disease in 73 patients with 81 affected hips. Radiographs were available for study from the onset of the disease until skeletal maturity. We used the Stulberg classification to assess outcome. The Herring grade and arthrographic sphericity proved to be the best predictors of final outcome. Combining these two values further increased the predictive value. All but one patient in Herring group A achieved an excellent outcome. In Herring group B, the age of the child and the sphericity of the femoral head influenced the end result. If the child was less than seven years old at the onset of symptoms the prognosis was invariably good and all spherical hips in group B had a good outcome with Stulberg grades 1 or 2. Moderately and severely deformed hips on arthrography resulted in Stulberg 3 and 4 hips. None of the hips in Herring group C had a normal appearance at maturity and the outcome was not significantly influenced by the age at onset or the arthrographic appearance


The Journal of Bone & Joint Surgery British Volume
Vol. 40-B, Issue 1 | Pages 116 - 122
1 Feb 1958
Dale GG Harris WR

1. The methods by which epiphyses receive their blood supply was studied by means of India ink injections in monkeys. Two types were identified depending upon whether the epiphysis was entirely or partly covered by articular cartilage. In the former, nutrient vessels enter the epiphysis by traversing the perichondrium at the periphery of the plate. In the latter they enter the epiphysis by penetrating the cortex at the side of the epiphysis at a point remote from the epiphysial plate. 2. The histological changes after separation of the second type of epiphysis were also studied. After temporary interference with endochondral ossification marked by increased thickness of the epiphysial plate, healing occurred so rapidly that within three weeks it was difficult to determine that the epiphysis had been separated at all. 3. It is concluded that when nutrient vessels enter an epiphysis at a point remote from the epiphysial plate, that epiphysis can be separated without serious disturbance to its blood supply and accordingly without interference with its capacity for growth. As it has been established that an epiphysis which is entirely covered by articular cartilage cannot be separated without destruction of its blood supply and subsequent avascular necrosis (Harris and Hobson 1956), it is concluded that the prognosis of an epiphysial separation is dependent upon the degree of damage to its blood supply rather than the mechanical disturbance of the epiphysial plate


The Journal of Bone & Joint Surgery British Volume
Vol. 52-B, Issue 4 | Pages 605 - 612
1 Nov 1970
Muheim G Bohne WH

In fifty-two knees with spontaneous osteonecrosis the diagnosis was based on a subchondral transradiancy in the weight-bearing surface of the medial femoral condyle. Strontium-85 scintimetry showed a unique pattern, indicating a lively repair reaction by localised high values. Thirteen of fifteen knees followed between two and twenty-three years developed osteoarthritis. The prognosis was based on the size of the transradiancy and the focality of the lesion as determined by scintimetry. It is suggested that scintimetry permits differentiation between primary osteoarthritis and arthritis secondary to osteonecrosis