For the purpose of investigating the effect of an insole with a lateral wedge, we studied 30 patients (31 knees) aged from 46 to 78 years with idiopathic osteonecrosis of the knee for at least three years. The 18 knees treated with an insole (group I) were matched by age, gender, obesity index, area of lesion, femorotibial angle, stage, and clinical evaluation with 13 treated conservatively without an insole (group II). The clinical results, as rated by a knee score, improved significantly more in group I than in group II. Radiologically, the necrotic area and ratio decreased in group I, whereas in group II they increased. In advanced cases, with stage 4 or a femorotibial angle of more than 180°, the use of an insole did not improve the clinical or radiological findings. The insole is a valuable method of conservative treatment for the early stages of osteonecrosis of the medial femoral condyle

We prospectively studied the clinical, arthroscopic and histological results of collagen-covered autologous chondrocyte implantation (ACI-C) in patients with symptomatic osteochondritis dissecans of the knee. The study included 37 patients who were evaluated at a mean follow-up of 4.08 years. Clinical results showed a mean improvement in the modified Cincinnati score from 46.1 to 68.4. Excellent and good clinical results were seen in 82.1% of those with juvenile-onset osteochondritis dissecans but in only 44.4% of those with adult-onset disease. Arthroscopy at one year revealed International Cartilage Repair Society grades of 1 or 2 in 21 of 24 patients (87.5%). Of 23 biopsies, 11 (47.8%) showed either a hyaline-like or a mixture of hyaline-like and fibrocartilage, 12 (52.2%) showed fibrocartilage. The age at the time of ACI-C determined the clinical outcome for juvenile-onset disease (p = 0.05), whereas the size of the defect was the major determinant of outcome in adult-onset disease (p = 0.01)

To investigate the effect of instability on the remodelling of a minor articular surface offset, we created a 0.5 mm coronal step-off of the medial femoral condyle in 12 New Zealand white rabbits and transected the anterior cruciate ligament (ACL). A control group of 12 rabbits had only ACL resection and the opposite knee was used as the non-operated control. The osteoarthritic changes at 6, 12 and 24 weeks after surgery were evaluated histologically. In addition, changes in the immunological detection of 3-B-3(-) and 7-D-4 chondroitin-6-sulphate epitopes were determined because of the previous association of such changes with repair of cartilage and early osteoarthritis. In the instability/step-off group there was rapidly progressing focal degeneration of cartilage on the high side of the defect, not seen in previous step-off studies in stable knees. The rest of the femoral condyles and the tibial plateaux of the instability/step-off group had moderate osteoarthritis similar to that of the instability group. 3-B-3(-) was detectable in the early and the intermediate stages of osteoarthritis but no staining was seen in the severely damaged cartilage zones. Immunoreactivity with 7-D-4 increased as degeneration progressed. Our findings have shown that even a minor surface offset may induce rapid degeneration of cartilage when the stability of the knee is compromised

We report 60 synovectomies of the knee in 51 children with juvenile chronic arthritis. Synovitis had been present for an average of 5 years and the average age at operation was 13 years. Results were evaluated in terms of pain, knee movement, relapse of synovitis and radiological change during a follow-up averaging 7.5 years. The relief of pain was rewarding and there was a slight postoperative gain in range of knee movement in most cases. The older the patient at onset of disease, the greater the risk of pain during follow-up. Progressive joint destruction was more common in younger patients, those with systemic or polyarticular disease, and those with highly active disease at the time of operation. Recurrence of synovitis was more frequent in patients who had their operation in a phase of high disease activity; this occurred most often in patients with polyarticular disease

We have developed an apparatus to measure the anteroposterior stability of the knee to forces of up to 250 N, applied at 20 degrees of flexion. We measured anterior laxity at 200 N, anterior stiffness at 50 N and total laxity at +/- 200 N. A study of cadaveric knees revealed that the soft tissues surrounding the bones had a significant influence on the force-displacement curve, and emphasised that differences between injured and normal pairs of knees are much more important than the absolute values of the parameters. In 61 normal volunteers we found no significant left to right differences in anterior laxity at 200 N and anterior stiffness at 50 N. In 92 patients with unilateral anterior cruciate deficiency there were significant differences (p less than 0.0005) in anterior laxity, anterior stiffness and total laxity, the injured-normal differences averaging 6.7 mm, 1.3 N/mm, and 8.1 mm respectively

Arthrodesis of the knee is a simple and safe operation that ensures stability and freedom from pain. But it is achieved at the expense of movement and occasionally of social acceptability. If arthroplasty is to be recommended, the advantages of arthrodesis must be retained, with the added bonus of a functional arc of movement

Pre-operative variables are increasingly being used to determine eligibility for total knee replacement (TKR). This study was undertaken to evaluate the relationships, interactions and predictive capacity of variables available pre- and post-operatively on patient satisfaction following TKR. Using nationally collected patient reported outcome measures and data from the National Joint Registry for England and Wales, we identified 22 798 patients who underwent TKR for osteoarthritis between August 2008 and September 2010. The ability of specific covariates to predict satisfaction was assessed using ordinal logistic regression and structural equational modelling. Only 4959 (22%) of 22 278 patients rated the results of their TKR as ‘excellent’, despite the majority (71%, n = 15 882) perceiving their knee symptoms to be much improved. The strongest predictors of satisfaction were post-operative variables. Satisfaction was significantly and positively related to the perception of symptom improvement (operative success) and the post-operative EuroQol-5D score. While also significant within the models pre-operative variables were less important and had a minimal influence upon post-operative satisfaction. The most robust predictions of satisfaction occurred only when both pre- and post-operative variables were considered together. These findings question the appropriateness of restricting access to care based on arbitrary pre-operative thresholds as these factors have little bearing on post-operative satisfaction. Cite this article: Bone Joint J 2013;95-B:1359–65

1. The results of twenty-eight "hinge" arthroplasties of the knee are described. 2. Failure was most often due to breaking of the prosthesis. 3. The design of the prosthesis has been modified as a result of experience in cases of mechanical failure. 4. The results suggest that with the use of the modified hinge good results may be obtainable in three out of four cases

1. The technique of compression-arthrodesis of the knee joint is described. 2. Fifteen consecutive cases are reported in which clinical union was detected at the first inspection from twelve days to six weeks after operation. By this method the total period of disability is reduced to three months. 3. Three mechanical factors which might be responsible for this very early clinical union are examined: compression is believed to be the main factor, although fixation is also important. 4. A fallacy is exposed in the use of bone grafts for arthrodesis of the knee; the graft is less osteogenic than the substance of the bones which form the joint, and it provides inefficient internal fixation. 5. A theory is suggested that compression, even in the presence of slight movement, acts by producing a fixed "hinge" without shearing movement; at this point a bridgehead of flexible osteoid tissue is established in which ossification inevitably takes place despite slight bending movement. 6. A second theory is suggested that high compression forces stimulate early union by liberating bone salts at points of maximum pressure through the action of osteoclasts, and that the local excess of bone salts is redeposited under cellular activity within a range of a few millimetres where there is no pressure

Reflex sympathetic dystrophy of the knee has been studied in a series of 19 patients. Those diagnosed and treated early (at less than six months) did much better than those diagnosed and treated late. Nevertheless, when these patients were followed up at an average of 3.4 years from onset, not one was completely normal to objective tests with the Cybex II dynameter, an indication of the adverse prognosis with current methods of treatment

We investigated the clinical, arthroscopic and biomechanical outcome of transplanting autologous chondrocytes, cultured in atelocollagen gel, for the treatment of full-thickness defects of cartilage in 28 knees (26 patients) over a minimum period of 25 months. Transplantation eliminated locking of the knee and reduced pain and swelling in all patients. The mean Lysholm score improved significantly. Arthroscopic assessment indicated that 26 knees (93%) had a good or excellent outcome. There were few adverse features, except for marked hypertrophy of the graft in three knees, partial detachment of the periosteum in three and partial ossification of the graft in one. Biomechanical tests revealed that the transplants had acquired a hardness similar to that of the surrounding cartilage. We conclude that transplanting chondrocytes in a newly-formed matrix of atelocollagen gel can promote restoration of the articular cartilage of the knee

We review the results of a modified quadricepsplasty in five children who developed stiffness of the knee after femoral lengthening for congenital short femur using an Ilizarov external fixator which spanned the knee. All had a full range of movement of the knee before lengthening was undertaken. Unifocal lengthening was carried out in the distal metaphysiodiaphyseal region of the distal femur with a mean gain of 6.5 cm. The mean percentage lengthening was 24%. At the end of one year after removal of the Ilizarov frame and despite intensive physiotherapy all patients had stiffness. Physiotherapy was continued after the quadricepsplasty and, at the latest follow-up (mean 27 months), the mean active flexion was 102° (80 to 130). The gain in movement ranged from 50° to 100°. One patient had a superficial wound infection which settled after a course of oral antibiotics. None developed an increased extension lag after surgery and all were very satisfied with the results. Quadricepsplasty is a useful procedure for stiffness of the knee after femoral lengthening which has not responded to physiotherapy

If conclusions are to be of any value they must be definite and one cannot draw definite conclusions from less than, say, fifty cases followed up for at least five years. However, few surgeons will ever see fifty patients requiring arthroplasty of the knee, let alone operate of them, even in five years. Accordingly, this account of a new approach to the problem of knee arthroplasty is submitted in the hope that other surgeons may care to try it and thereby learn, and thus be able to teach, tile modifications and improvements that all new techniques seem so surely to need

The Kodama-Yamamoto knee is an uncemented surface replacement which has been used since 1970. The design has been improved twice and this present report concerns the results of the Mark II model. Between 1980 and 1984, 350 knees were replaced in 225 patients. In 1987, a survey of 335 of these knees was conducted at two to seven years after operation. The results were excellent or good in 83% of patients. Many of the failures were because of general disorders unrelated to the operation, but in 5.4% of the knees there were local complications which continue to present problems

We evaluated histologically samples of synovial tissue from the knees of 50 patients with rheumatoid arthritis (RA). The samples were taken during revision for aseptic loosening. The findings were compared with those in 64 knees with osteoarthritis (OA) and aseptic loosening and in 18 knees with RA without loosening. The last group had been revised because of failure of the inlay or the coupling system of a constrained prosthesis. All the patients had had a total ventral synovectomy before implantation of the primary prosthesis. In all three groups a foreign-body reaction and lymphocellular infiltration were seen in more than 80% of the tissue samples. Deposits of fibrin were observed in about one-third to one-half of the knees in all groups. Typical signs of the reactivation of RA such as rheumatoid necrosis and/or proliferation of synovial stromal cells were found in 26% of knees with RA and loosening, but not in those with OA and loosening and in those with RA without loosening. Our findings show that reactivation of rheumatoid synovitis occurs after total knee replacement and may be a cofactor in aseptic loosening in patients with RA

Our objectives were to establish the envelope of passive movement and to demonstrate the kinematic behaviour of the knee during standard clinical tests before and after reconstruction of the anterior cruciate ligament (ACL). An electromagnetic device was used to measure movement of the joint during surgery. Reconstruction of the ACL significantly reduced the overall envelope of tibial rotation (10° to 90° flexion), moved this envelope into external rotation from 0° to 20° flexion, and reduced the anterior position of the tibial plateau (5° to 30° flexion) (p < 0.05 for all). During the pivot-shift test in early flexion there was progressive anterior tibial subluxation with internal rotation. These subluxations reversed suddenly around a mean position of 36 ± 9° of flexion of the knee and consisted of an external tibial rotation of 13 ± 8° combined with a posterior tibial translation of 12 ± 8 mm. This abnormal movement was abolished after reconstruction of the ACL

We report nine cases of irreducible congenital dislocation of the knee which were treated by early operation with good results. All were resistant to conservative measures and operation was performed at an average age of nine months. The essential abnormality was a short quadriceps muscle together with subluxation of the hamstring muscles to lie anterior to the axis of knee flexion. The quadriceps tendon was lengthened by VY-plasty and in six cases additional length was gained by proximal mobilisation of the muscle. After operation all the patients were able to walk

A prospective, randomised, controlled trial compared two different techniques of high tibial osteotomy with a lateral closing wedge or a medial opening wedge, stabilised by a Puddu plate. The clinical outcome and radiological results were examined at one year. The primary outcome measure was the achievement of an overcorrection of valgus of 4°. Secondary outcome measures were the severity of pain (visual analogue scale), knee function (Hospital for Special Surgery score), and walking distance. Between January 2001 and April 2004, 92 patients were randomised to one or other of the techniques. At follow-up at one year the post-operative hip-knee-ankle angle was 3.4° (± 3.6° . sd. ) valgus after a closing wedge and 1.3° (± 4.7° . sd. ) of valgus after an opening wedge. The adjusted mean difference of 2.1° was significant (p = 0.02). The deviation from 4° of valgus alignment was 2.7° (± 2.4° . sd. ) in the closing wedge and 4.0° (± 3.6° . sd. ) in the opening-wedge groups. The adjusted mean difference of 1.67° was also significant (p = 0.01). The severity of pain, knee score and walking ability improved in both groups, but the difference was not significant. Because of pain, the staples required removal in 11 (23%) patients in the closing-wedge group and a Puddu plate was removed in 27 (60%) patients in the opening-wedge group. This difference was significant (p < 0.001). We conclude that closing-wedge osteotomy achieves a more accurate correction with less morbidity, although both techniques had improved the function of the knee at one year after the procedure

A patient with typical congenital contractural arachnodactyly followed up from the age of 12 years to the age of 48 is reported. He had spiderlike fingers and toes and marked contractures of the knees, ankles, toes, shoulders, elbows and fingers; the mobility of the hips and wrists was almost normal. Persistent knee contractures prevented him from walking. In his twenties he had an osteotomy of both femora and shortening of the patellar tendons which enabled him to walk for the first time in an upright position without external support. When seen at the age of 48 the range of movement of his knees was 0 to 90 degrees. He was working as a turner and had been doing so for almost 20 years