In an experimental clinical study, 25 implants of pure titanium were inserted into the proximal tibia of 11 volunteer patients, four with rheumatoid arthritis and seven with osteoarthritis. The implants were removed from five weeks to 24 months later and detailed histological analysis was performed. The implants generally healed with direct bone-metal contact, showing so-called osseointegration. Only one of the 21 implants which had been in place for over five months did not show osseointegration, probably because of inadequate primary contact with bone. The presence of rheumatoid disease did not prevent osseointegration, but accompanying osteoporosis seemed to be a risk factor

The term "floating knee" describes the flail joint resulting from fractures of the shaft or adjacent metaphyseal region of the ipsilateral femur and tibia; we have reviewed 15 children with this combined injury seen at the Winnipeg Children's Hospital. All had been involved in motor vehicle accidents, eight having been struck while cycling; the biomechanics of such an injury have also been studied. Treatment is difficult and the regimes varied. Results were poor when both fractures were treated nonoperatively and we recommend that at least one of the fractures should be rigidly fixed

We studied 37 patients with varus osteoarthritis of the knee to determine the influence of the bone mineral density (BMD) on the varus deformity. There were 15 men (21 knees) and 22 women (38 knees). The mean age of the men was 69 years and of the women 68 years. BMD was measured in the L1–L4 spinal region using dual X-ray absorptiometry. In the women a low level of BMD was associated with varus deformity originating at the proximal tibia, but a high level was predominantly linked with deformity originating in the joint space. Similar findings were obtained in the men. Our results suggest that a low BMD predisposes to trabecular microfractures and consequently increased stress on the articular cartilage. A low BMD does not preclude osteoarthritic change in the knee

Fifty-three ununited fractures with a median time since injury of 28 months were treated by electrical stimulation using pulsing electromagnetic fields. Union was achieved in 38 cases (71.7 per cent) in a median time of six months. For ununited fractures of the tibia the success rate was higher at 86.7 per cent. Previous or active sepsis, the presence of plates or nails, the age of the patient or the time since the injury did not affect the results. Analysis of the failures suggests that inadequate immobilisation, a fracture gap of more than five millimetres or the presence of a screw in the fracture gap was responsible. In four patients no cause of failure could be determined

Seven patients with stress fractures of the femoral neck were treated at the Military Hospital of Thessaloniki, Greece between 1972 and 1976. Their average age was 22 years. Stress fractures of the femoral neck are not as common as stress fractures of the metatarsals or tibia and other bones. Intense muscular activity was the main cause of these stress fractures which were only classed as such in the absence of any injury. Pain and stiffness around the hip were reported by all seven patients before admission. Results of laboratory investigations of the patients' alkaline phosphatase and serum calcium levels were normal. One patient received surgical treatment and the other patients were treated conservatively. Healing was uneventful in all

We prospectively evaluated the percutaneous injection of autogenous bone marrow for the treatment of active simple bone cysts in ten consecutive children with cysts in the proximal humerus, proximal femur or tibia. The treatment included percutaneous biopsy, aspiration of fluid and the injection of autogenous bone marrow aspirated from the iliac crest. All the patients became painfree after a mean of two weeks and resumed full activities within six weeks. All ten cysts consolidated radiologically and showed remarkable remodelling within four months. Review at 12 to 48 months showed satisfactory healing without complications. Percutaneous injection of autologous bone marrow appears to be an effective treatment for active simple bone cysts

Diaphyseal fractures of the tibia in 80 patients were treated by external skeletal fixation using a unilateral frame, either in a fixed mode or in a mode which allowed the application of a small amount of predominantly axial micromovement. Patients were allocated to each regime by random selection. Fracture healing was assessed clinically, radiologically and by measurement of the mechanical stiffness of the fracture. Both clinical and mechanical healing were enhanced in the group subjected to micromovement, compared to those treated with frames in a fixed mode possessing an overall stiffness similar to that of others in common clinical use. The differences in healing time were statistically significant and independently related to the treatment method. There was no difference in complication rates between treatment groups

In vitamin D-fed chicks 1,25-dihydroxyvitamin D3 and 24,25-dihydroxyvitamin D3 were implanted into experimentally-produced fractures of the mid-tibia. The mechanical and biochemical properties of the tibia were evaluated for two weeks, including torsion tests, measurement of alkaline phosphatase activity, 45Ca incorporation, and Ca2+ content. Both dihydroxylated metabolites of vitamin D3 had a direct effect on endochondral bone formation. 24,25(OH)2D3 strengthened the callus, and raised alkaline phosphate activity in the first seven days after fracture. 1,25(OH)2D3 decreased the strength of the callus concomitant with a reduction in 45Ca incorporation. It is suggested that local application of 24,25(OH)2D3 into fractures may accelerate healing and prevent non-union

Nuclear magnetic resonance imaging (MRI) was used to study the normal knee. As well as revealing bone quality, MRI provided useful information on intra-articular and extra-articular soft tissues. Midsagittal views gave clear images of the cruciate ligaments, and of the patellar and quadriceps tendons. Parasagittal views were the best for delineating the menisci which, like ligaments and tendons, are of low intensity; the semimembranosus tendon and its insertion to the proximal tibia were also seen clearly in these views. The cruciate ligaments and menisci, though visible in the coronal view also, were better seen in the sagittal view. Axial views provided information on the structure of the patella, its cartilage, the patellofemoral joint and posterior soft-tissue structures

We report our results in 24 children with malignant primary bone tumours of the distal femur treated with a Stanmore extendible endoprosthesis (SEER). This consists of a femoral component that can be lengthened, a constrained knee and an uncemented sliding tibial component which crosses the proximal tibial physeal plate perpendicularly. The average age of the patients at diagnosis was ten years and the mean follow-up was 4.7 years (2.5 to 7.9). The mean growth of the affected tibia was 76% (18 to 136) and of the fibula 83% (15 to 750) of the growth of the unaffected limb. Measurement of growth arrest lines showed that the mean growth of the proximal tibial physis on the affected side was 69% (43 to 100) of that of the normal side. The great variability in the growth of the physis cannot yet be explained

We have assessed the effectiveness of reconstruction of the anterior cruciate ligament (ACL) in reducing functional tibial translation (TT). The gait of 11 ACL-deficient patients was studied using Vicon equipment before and after surgery. Measurements of the angle between the patellar tendon and the long axis of the tibia were obtained in order to calculate TT in the sagittal plane relative to the uninjured limb during standing and walking. Before surgery, patients did not show abnormal TT on the injured side, but after surgery significant anterior TT was found in the operated limb for every parameter of gait. Abnormal anterior TT occurring during activity does not seem to be reduced by reconstruction; rather, it increases. It may be that the increased translation results from relaxation of excess contraction of the hamstring muscles, since compensatory muscle activity no longer is required in a reconstructed knee. The reduction of TT may not be an appropriate objective in surgery on the ACL

Posterolateral instability of the knee is difficult to diagnose and treat. It has been attributed to failure of ligament reconstruction and has been the cause of numerous knee operations. We present a small group of patients who complained of giving way of the knee and who had an increased range of external rotation of the tibia at 90 degrees knee flexion. The patients all had similar symptoms. We describe the standing apprehension test, which was positive in every case. Anterior subluxation of the lateral femoral condyle was detected manually in four patients and confirmed by radiography and MRI in one. The medial knee pain which is often associated with episodes of instability is probably due to stretching of the posteromedial soft tissues and perhaps the saphenous nerve

We have studied the progression of healing in 103 unstable fractures of the tibia. In 76 patients we removed the external fixator once the stiffness had reached 15 Nm/° in the sagittal plane. Deformity at the site of the fracture subsequently occurred in four patients. In a further 27, we measured stiffness in several planes and removed the fixator only when the stiffness reached 15 Nm/° in each. We found that stiffness in two orthogonal planes may differ widely (maximum difference 9.0 Nm/°, mean 4.1 Nm/°). There were no failures in the second group. We advocate that fracture stiffness be measured in two orthogonal planes when assessing tibial healing and suggest that values above 15 Nm/° in two planes give an indication that it is safe to remove the fixator

We reviewed 24 feet in 15 patients who had undergone talectomy for recurrent equinovarus deformity; 21 were associated with arthrogryposis multiplex congenita, two with myelomeningocele and one with idiopathic congenital talipes equinovarus. The mean follow-up was 20 years. Good results were achieved in eight feet (33%) in which further surgery was not needed and walking was painless; a fair result was obtained in ten feet (42%) in which further surgery for recurrence of a hindfoot deformity had been necessary but walking was painless; the remaining six feet (25%) were poor, with pain on walking. All patients wore normal shoes and could walk independently, except one who was wheelchair-bound because of other joint problems. Recurrent deformity, the development of tibiocalcaneal arthritis and spontaneous fusion of the tibia to the calcaneum were all seen in these patients

Thirteen patients with dyschondrosteosis from eight families are reviewed and their clinical and radiographic variation noted. Inheritance is likely to be autosomal dominant but with only 50 per cent penetrance. Stature was moderately reduced, due to shortening of the bones of the leg. Radio-ulnar shortening could either involve both bones equally or the radius predominantly, in which case a typical Madelung deformity was seen. Tibio-fibular disproportion was present in half the patients, two of them having severe deformity associated with tibia varum and a long fibula. The treatment of one of these patients is described. It is recommended that patients with dyschondrosteosis should be kept under surveillance during the growing period. Problems in the limbs, especially the legs, may require operations to equalise the length of the two bones

Between 1990 and 1998 we saw 21 children with primary subacute haematogenous osteomyelitis. Pain, swelling and a limp had been present for two to 12 weeks with little functional impairment. Laboratory tests were non-contributory. The lesions were classified radiologically into metaphyseal, diaphyseal, epiphyseal and vertebral. There were 24 sites involved, with most (20) being in the tibia; 17 lesions were in the diaphysis, five in the metaphysis and two in the epiphysis. The diagnosis was confirmed histologically in all cases. Staphylococcus aureus was cultured in six patients. Healing occurred in all patients after treatment with antibiotics for six weeks and radiological improvement was seen after three to six months. Subacute osteomyelitis develops as a result of increased host resistance and decreased bacterial virulence. The radiological features can mimic various benign or malignant bone tumours and non-pyogenic infections. Histological confirmation is necessary to avoid a delay in diagnosis

1. An operation to re-establish the continuity of the bone after resection of tumours of the lower end of the femur or upper end of the tibia is described. 2. Sound bony union may be obtained, allowing walking with weight bearing after three to four months. 3. The combination of a massive tibial or femoral graft (Juvara procedure) with an intramedullary nail, a massive homogenous graft, and fixation of the patella to the autograft to accelerate its revascularisation. has given constant and rapid bony union in five cases. 4. This possibility gives real value to wide resection in the treatment of severe cases of giant-cell tumours. especially those that are recurrent. osteolytic or suspect of malignancy. 5. Its value in the treatment of sarcoma cannot be assessed in so short a series

We reviewed retrospectively 490 patellar ligament reconstructions for cruciate ligament injuries performed from 1980 to 1990. There were six cases of patellar splitting and three displaced patellar fractures in donor knees. The fissure fractures all occurred during the removal of the patellar bone block. The displaced fractures were sustained during early rehabilitation, and in two of the three patients, involved the normal contralateral knee. The major reasons for this complication were imprecise saw cuts, spreading osteotomies, and the use of a too large patellar bone block. When a trapezoidal bone block is used to self-lock in the femoral tunnel, this should preferably be taken from the tibia. Special care is needed in rehabilitation when the graft has been taken from the contralateral knee

A biomechanical study has been carried out on 20 cadaveric knees to investigate their load-absorbing mechanism. The impact load was applied using a weight falling onto the transected proximal femur and the force transmitted through the knee was measured at the transected distal tibia using a load transducer. The peak force transmitted increased as, sequentially, meniscus, articular cartilage and subchondral bone were damaged or removed. The most striking result was found in an implanted knee replacement where the transmitted force reached 180% of that in the intact knee. The results show that the joint has an impact-absorbing property in each segment and that in the osteoarthritic knee there is less absorption of shock than in the normal knee. The high impact force in an implanted knee suggests that microfractures of the cancellous bone might be expected and may produce loosening