Aims

The aim of this study was to present a series of patients with aseptic failure of a total ankle arthroplasty (TAA) who were treated with fusion of the hindfoot using a nail.

Using a new, non-invasive method, we measured the patellofemoral force (PFF) in cadaver knees mounted in a rig to simulate weight-bearing. The PFF was measured from 20° to 120° of flexion before and after implanting three designs of knee prosthesis. Medial unicompartmental arthroplasty with a meniscal-bearing prosthesis and with retention of both cruciate ligaments caused no significant change in the PFF. After arthroplasty with a posterior-cruciate-retaining prosthesis and division of the anterior cruciate ligament, the PFF decreased in extension and increased by 20% in flexion. Implantation of a posterior stabilised prosthesis and division of both cruciate ligaments produced a decrease in the PFF in extension but maintained normal load in flexion. There was a direct relationship between the PFF and the angle made with the patellar tendon and the long axis of the tibia. The abnormalities of the patellar tendon angle which resulted from implantation of the two total prostheses explain the observed changes in the PFF and show how the mechanics of the patellofemoral joint depend upon the kinematics of the tibiofemoral articulation

The levels of the active metabolites of vitamin D were measured in the callus and in the epiphyseal growth plate of chicks given radioactive cholecalciferol during fracture healing. Those levels were correlated with the histological findings. Three groups of chicks were studied: a control group with no fracture, chicks with fractures fixed by Kirschner wire, and chicks with unfixed fractures. A significant increase in the levels of the active metabolites was found in the callus during the first few days after fracture. The levels of 25-hydroxycholecalciferol [25(OH)D3] and of 24,25-dihydroxycholecalciferol [24,25(OH)2D3] were higher when there was no fixation, while those of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] were higher after fixation. The concentrations of these metabolites in the proximal epiphysis of the tibia were similar to those found in the callus. Based on these findings it is suggested that the active metabolites of vitamin D are directly involved in the process of fracture repair

Disruption of the major ligaments of the knee was seen in six young men, five parachutists and a house painter, after what we have termed abduction-traction injury. This unusual complaint results from the application of a sudden block to the ankle while falling head first, leading to traction and abduction of the knee. All the patients underwent operations, generally with unsatisfactory results. At operation tears of the anterior cruciate ligament, medial collateral ligament and posterior oblique ligament were seen in each case; in four patients the posterior capsule and in three the posterior cruciate ligament also were torn. In one patient the lateral collateral ligament was torn and the lateral meniscotibial ligament was avulsed. The compression component is absent in this type of injury and consequently the menisci and the osteochondral surfaces of the tibia and femur remained intact in each case

The management of twenty-one children with a defect of the tibial shaft due to acute haematogenous osteomyelitis is described. Half the defects were due to removal of the sequestrum before the involucrum had formed. Only four patients, all under ten years of age, had spontaneous regeneration of the shaft. Eleven children had a posterior tibiofibular graft and six had a transfer of the ipsilateral fibular diaphysis. The results of operation were superior to those of spontaneous regeneration. All the grafts united and the children returned home to lead normal lives. Shortening was only a problem when growth plates or adjacent joints had been damaged. We now leave the sequestrum for up to one year after the onset of infection. If the involucrum fails to form we reconstruct the tibia as soon as possible after sequestrectomy

Immobilisation causes denervation-like changes in the motor endplates, decreases the content of IGF-I, and increases the number of IGF-I receptors in the spinal cord. In the rat we investigated whether similar changes occur after a fracture of the midshaft of the femur which had been treated by intramedullary fixation with adequate or undersized pins. A more pronounced reduction in muscle wet weight was seen after fixation by undersized pins as well as decreased ash density of the ipsilateral tibia which did not completely return to normal within the 12-week experimental period. The nicotinic cholinergic receptors in the motor endplates of tibialis anterior were increased (p < 0.01) and there was a significant increase (p < 0.02) in IGF-I receptors in the lumbar spinal cord ipsilateral to the fracture after treatment by undersized nails. These changes may be associated with the impaired proprioception, co-ordination and motor activity which are sometimes seen after fractures

Objectives

It has been hypothesized that patellofemoral pain, a common knee condition in adolescents and young adults, may be a precursor of degenerative joint changes and may ultimately lead to patellofemoral osteoarthritis. Since both conditions share several mechanical disease characteristics, such as altered contact area between the femur and patella and increased joint stress, we investigated whether these conditions share similar and different shape characteristics of the patella compared with normal controls.

We studied the various drill bits available for engineering purposes, and compared them with standard orthopaedic drill bits, using continuous temperature recording at 0.5 mm, 1.0 mm and 1.5 mm from the edge of a 2.5 mm hole as it was drilled in fresh cadaver human tibia. We found that some commercially available drill bits performed better than their orthopaedic equivalents, producing significantly less thermal injury to the surrounding bone and halving the force required for cortical penetration. Our work suggests that the optimal bit for orthopaedic purposes should have a split point and a quick helix. Theoretical knowledge of cutting technology predicts that the addition of a parabolic flute will further reduce thermal damage. Further work is being done on other drill sizes used in orthopaedic practice and on new custom-designed bits

We performed limb lengthening and correction of deformity of nine long bones of the lower limb in six children (mean age, 14.7 years) with osteogenesis imperfecta (OI). All had femoral lengthening and three also had ipsilateral tibial lengthening. Angular deformities were corrected simultaneously. Five limb segments were treated using a monolateral external fixator and four with the Ilizarov frame. In three children, lengthening was done over previously inserted femoral intramedullary rods. The mean lengthening achieved was 6.26 cm (mean healing index, 33.25 days/cm). Significant complications included one deep infection, one fracture of the femur and one anterior angulation deformity of the tibia. The abnormal bone of OI tolerated the external fixators throughout the period of lengthening without any episodes of migration of wires or pins through the soft bone. The regenerate bone formed within the time which is normally expected in limb-lengthening procedures performed for other conditions. We conclude that despite the abnormal bone characteristics, distraction osteogenesis to correct limb-length discrepancy and angular deformity can be performed safely in children with OI

Aims

The aim of this study was to validate the Mirels score in predicting pathological fractures in metastatic disease of the lower limb.

In ten male rats we inserted ceramic ‘drawing-pin’ implants in weight-bearing positions within the right proximal tibia. Two animals were killed 6 weeks after surgery and two more 14 weeks after surgery. The remaining six received intra-articular injections of either high-density polyethylene (4 rats) or saline (2 rats) at 8, 10 and 12 weeks after surgery. These animals were killed two weeks after the last injection. Histological examination of the bone-implant interface in the control animals showed appositional bone growth around the implant at both 6 and 14 weeks. Polyethylene, but not saline, caused a chronic inflammatory response with numerous foreign-body giant cells in periprosthetic tissues. Our model of a stable, weight-bearing bone-implant interface provides a simple and reliable system in which to study in vivo the effects of particulate materials used in orthopaedic surgery

We report the use of the uncemented Kotz modular femur and tibia reconstruction system after 95 distal femoral resections performed from 1983 to 1989. The average follow-up was 51 months; 62 patients had at least 36 months' follow-up and 36 at least 60 months. Complications required reoperation in 55%. The postoperative infection rate was 5% for primary cases, 6% for revision cases, and 43% for revision of previously infected cases. The polyethylene bushes failed in 42% of cases at an average of 64 months postoperatively. Stem breakage occurred in 6% and was associated with the use of narrow stems and extensive quadriceps excision. The radiological results were excellent or good in most cases and were related to the initial screw fixation, but not to age, chemotherapy, length of resection or size of stem. The clinical results were excellent or good in 75%, failure usually being associated with a complication, especially infection

The quantification of local bone blood flow in man has not previously been possible, despite its importance in the study of normal and pathological bone. We report the use of positron emission tomography, using 15O-labelled water, to measure bone blood flow in patients with closed unilateral fractures of the tibia. We compared fractured and unfractured limbs; alterations in blood flow paralleled those found in animal models. There was increased tibial blood flow at the fracture site as early as 24 hours after fracture, reaching up to 14 times that in the normal limb at two weeks. Blood flow increase was less in displaced than in undisplaced fractures. The muscle to bone ratios of blood flow were similar to those in previous animal work using other techniques. Positron emission tomography will allow study of human bone blood flow in vivo in a wide variety of pathological conditions

We reviewed 46 leg-shortening operations (37 femoral and nine tibial), performed by different methods, to assess the incidence of complications and permanent disability. Shortening of as much as 7.5 cm in the femur and 5 cm in the tibia was achieved in men of normal height without any loss of function. Complications were seen with all surgical techniques despite the use of modern implants. Most problems arose from inadequate stabilisation of the osteotomy. The most reliable method of femoral shortening was open subtrochanteric osteotomy with preservation of the isthmus, and fixation with an intramedullary nail locked at its proximal end. In tibial shortening, bone excision should be at the level of the flare in the lower diaphysis in order to achieve reliable bone healing. Simple intramedullary nail fixation should be supplemented with a long-leg cast for six weeks or the nail should be locked at both ends to prevent postoperative distraction or rotation

The mechanism of the pivot shift was investigated by analysing movements under valgus torque in 29 fresh cadaveric knees. The movements were measured in three dimensions, using biplanar photography, when all the ligaments were intact, and then after the ligaments were sequentially divided. When only the anterior cruciate ligament was sectioned, the pivot shift occurred in seven out of 20 knees examined. In the other 13, though the pivot shift was not observed, an abnormal internal rotation occurred at between 10 degrees and 50 degrees of flexion. Division of the iliotibial tract in addition to division of the anterior cruciate ligament stopped the pivot shift, as the tibia remained internally rotated throughout the range of flexion. The axis of rotation of the pivot shift was located at the medial collateral ligament, which was kept tight by the applied valgus torque. The sudden movement in the pivot shift was caused by a complex interaction between the geometry of the knee and the valgus torque applied

Four different experiments were performed to study the healing of a large, non-vascularised, diaphyseal, bone segment in adult cats. In the first experiment, a 4 cm segment of tibia with its periosteum was excised and replaced in its bed. The other experiments were similar, except that in the second, the periosteum of the segment was removed, in the third its medullary canal was blocked with a Silastic rod, and in the last group the segment was isolated from its muscle bed by a Silastic sheet. The reparative processes were quantified by estimating the resorption index, the cortical new bone formation index, the callus encasement index, and the osteocyte count. Bone resorption and apposition occurred in the segment even when the periosteum was absent or the medullary canal was blocked, with osseous union at both ends by eight to 12 weeks, provided the segment was not isolated from its muscle bed. Thus, the muscle bed played a significant role in these reparative processes

To study the effect of ligament injuries and surgical repair we investigated the three-dimensional kinematics of the ankle joint complex and the talocrural and the subtalar joints in seven fresh-frozen lower legs before and after sectioning and reconstruction of the ligaments. A foot movement simulator produced controlled torque in one plane of movement while allowing unconstrained movement in the remainder. After testing the intact joint the measurements were repeated after simulation of ligament injuries by cutting the anterior talofibular and calcaneofibular ligaments. The tests were repeated after the Evans, Watson-Jones and Chrisman-Snook tenodeses. The range of movement (ROM) was measured using two goniometer systems which determined the relative movement between the tibia and talus (talocrural ROM) and between the talus and calcaneus (subtalar ROM). Ligament lesions led to increased inversion and internal rotation, predominantly in the talocrural joint. The reconstruction procedures reduced the movement in the ankle joint complex by reducing subtalar movement to a non-physiological level but did not correct the instability of the talocrural joint

Three amputated legs with tibial dysplasia were studied by radiography, arteriography and anatomical dissection. The radiographic appearances were the same as the Type 1b tibial dysplasia described by Jones, Barnes and Lloyd-Roberts (1978) in that the tibiae were absent but the lower femoral epiphyses were normal. However, our anatomical findings differed from those of Jones et al. since no bony or cartilaginous anlage of the proximal tibia was found in any of the three legs. The pattern of vascular anomaly was identical in the three legs and similar to the findings of Hootnick et al. (1980) in congenital short fibula. Congenital fusion of the subtalar joint was a constant finding. These results support the hypothesis that the arterial and skeletal systems are vulnerable to a teratogenic insult in the fifth week of embryonic life. The bony and arterial anomalies should be borne in mind by the surgeon attempting reconstructive surgery for this condition

1. Measurements have been made of the relative calcification of different types of bone in tibia of the rabbit at the ages of six weeks, three and a half months and seven months by comparing their absorption of x-rays. 2. Calcified cartilage is between 8 and 10 per cet more highly calcified than periosteal and endosteal bone and about 20 per cent more highly calcified than bone formed immediately adjacent to cartilage. 3. Young and adult bones have a framework of approximately the same strength; that is, calcified cartilage, bone adjacent to cartilage and the interstitial areas of periosteal and endosteal bone have each approximately the same degree of calcification at all ages. 4. Adult rabbit bone approaches uniform calcification throughout, equal to the calcification of the interstitial areas of periosteal and endosteal bone. Evidence for this is the replacement of the lowly calcified epiphysial bone by osteones of higher calcification

1. The movements of flexion and extension at the knee joint take place above the menisci; the movements of rotation take place below the menisci. 2. The popliteus muscle consists of two halves, one being attached by tendon to the femur, the other by aponeurosis to the lateral meniscus. The action of the muscle is to rotate the knee and retract the posterior arch of the lateral meniscus. The flexing action of the muscle is quite negligible. 3. The effects of rotation of the knee joint on the two menisci are dissimilar. The medial meniscus is distorted during rotation; its horns move with the tibia, but the intervening arch moves with the femur, and the distortion renders it liable to injury during rotation. The lateral meniscus does not become distorted during rotation; it follows the lateral condyle of the femur by reason of the attachments of the ligaments of Humphry and Wrisberg and the popliteus muscle. It is thus relatively immune from injury daring rotation