We have studied the concept of posterior condylar offset and the importance of its restoration on the maximum range of knee flexion after posterior-cruciate-ligament-retaining total knee replacement (TKR). We measured the difference in the posterior condylar offset before and one year after operation in 69 patients who had undergone a primary cruciate-sacrificing mobile bearing TKR by one surgeon using the same implant and a standardised operating technique. In all the patients true pre- and post-operative lateral radiographs had been taken. The mean pre- and post-operative posterior condylar offset was 25.9 mm (21 to 35) and 26.9 mm (21 to 34), respectively. The mean difference in posterior condylar offset was + 1 mm (−6 to +5). The mean pre-operative knee flexion was 111° (62° to 146°) and at one year postoperatively, it was 107° (51° to 137°). There was no statistical correlation between the change in knee flexion and the difference in the posterior condylar offset after TKR (Pearson correlation coefficient r = −0.06, p = 0.69)

Objectives. The objective of this study was to compare the early migration characteristics and functional outcome of the Triathlon cemented knee prosthesis with its predecessor, the Duracon cemented knee prosthesis (both Stryker). Methods. A total 60 patients were prospectively randomised and tibial component migration was measured by radiostereometric analysis (RSA) at three months, one year and two years; clinical outcome was measured by the American Knee Society score and the Knee Osteoarthritis and Injury Outcome Score. Results. There were no statistically significant differences in rotation or translation around or along the three coordinal axes, or in the maximum total point motion (MTPM) during the two-year follow-up. Conclusions. The Triathlon cemented knee prosthesis has similar early stability and is likely to perform at least as well as the Duracon cemented knee prosthesis over the longer term

If patients could recall their physical status before total hip (THA) or knee arthroplasty (TKA) accurately it could have valuable applications both clinically and for research. This study evaluated the accuracy of a patient’s recollection one year after either THA or TKA using the Oxford hip or knee scores (OHS and OKS). In total, 113 patients (59 THA, 54 TKA) who had completed the appropriate score pre-operatively were asked to complete the score again at a mean of 12.4 months (standard deviation (. sd. ) 0.8) after surgery, recalling their pre-operative state. While there were no significant differences between the actual and recalled pre-operative scores (OHS mean difference 0.8, . sd. 6.21, 95% confidence interval (CI) -0.82 to 2.42, p = 0.329; OKS mean difference -0.11, . sd. 7.34, 95% CI -2.11 to 1.89, p = 0.912), absolute differences were relatively large (OHS, 5.24; OKS, 5.41), correlation was weak (OHS r = 0.7, OKS r = 0.61) and agreement between actual and recalled responses for individual questions was poor in half of the OHS and two thirds of the OKS. A patient’s recollection of pre-operative pain and function is inaccurate one year after THA or TKA. Cite this article: Bone Joint J 2015;97-B:1070–5

We describe a rare form of congenital snapping knee. In six knees in four children, the tibia subluxed anteriorly on the femur when the knee was extended and reduced spontaneously on flexion. The abnormal movements were seen and felt as sudden snaps or clunks at about 30 degrees of flexion. All six knees showed similar dysplastic features, although the patients had different clinical syndromes. The mechanism of the subluxation and its management are discussed

In 13 unloaded living knees we confirmed the findings previously obtained in the unloaded cadaver knee during flexion and external rotation/internal rotation using MRI. In seven loaded living knees with the subjects squatting, the relative tibiofemoral movements were similar to those in the unloaded knee except that the medial femoral condyle tended to move about 4 mm forwards with flexion. Four of the seven loaded knees were studied during flexion in external and internal rotation. As predicted, flexion (squatting) with the tibia in external rotation suppressed the internal rotation of the tibia which had been observed during unloaded flexion

Between March 1987 and March 1997, we performed a modified Thompson quadricepsplasty on 20 stiff knees and followed the patients for a mean of 35 months (24 to 52). After the operation, the knee was immobilised in flexion and periodically extended. At the final follow-up, the mean active flexion was 113.5° (75 to 150). The final mean gain in movement was 67.6° (5 to 105). One patient had a deep infection which resolved after wound care and intravenous antibiotics. The modified Thompson quadricepsplasty with appropriate postoperative care can give good results

In a group of 25 patients with traumatic dislocation of the knee, four, all of whom had similar ligament and medial soft-tissue injuries, also had associated lateral patellar dislocation. In all four reconstruction was delayed because of their other serious injuries. Having encountered the combination of knee dislocation and lateral patellar dislocation in 16% of our patients, we believe that it may be less rare than is commonly believed. We think that it is important to maintain a high index of suspicion of possible patellar dislocation when medial structures have been severely damaged. Early recognition and immobilisation in extension can prevent fixed lateral dislocation of the patella

The accurate assessment of compartmental involvement in degenerative arthritis of the knee is important when planning operative treatment. Standard radiographic techniques often fail to define the degree of involvement of the less affected tibiofemoral compartment. The use of stress radiography in the preoperative assessment of 30 knees with degenerative arthritis is described and the radiographic findings correlated with the changes found at arthrotomy

1. Methods of correcting flexion contractures of the knee following poliomyelitis fail if posterior subluxation of the tibia is allowed to occur. 2. Careful serial manipulations will give straight, congruous joints in younger patients. Posterior capsulotomy does not facilitate correction. 3. Supracondylar femoral osteotomy is indicated in children over fifteen and in adults, although sometimes arthrodesis of the knee is necessary

1. An analysis of 171 cases of compression arthrodesis in the knee is presented. 2. A total success rate of 98·8 per cent was revealed. 3. The average time between operation and walking free of splintage was nine weeks. 4. When the compression was removed, after an average period of four weeks, 88·2 per cent of the knees already showed clinical union

1. High tibial osteotomy-above the tibial tubercle-gives good results in elderly patients disabled by arthritis of the knee. 2. A technique of operation is described in which fixation is secured by four pins gripped in compression clamps. 3. No other fixation is needed, and knee movements and walking are encouraged within a few days of operation. 4. The early results warrant further trial of the method

1. If osteoarthritis of the knee is confined mainly to one tibio-femoral compartment and the range of flexion is 90 degrees or more it can be treated safely and reliably by proximal tibial osteotomy. 2. The operation relieves pain in a large proportion of cases while retaining a useful range of knee flexion. We are grateful to Miss H. M. Briggs, Research Secretary at Harlow Wood Orthopaedic Hospital, for secretarial assistance

We studied the complications after open-wedge osteotomy by hemicallotasis in 308 consecutive patients, most of whom had osteoarthritis of the knee. The participating surgeons, who worked at 17 hospitals, used their discretion in selecting patients, operating techniques and external fixators. The general complications included 11 cases of deep-vein thrombosis (4%), six of nonunion (2%) and one of septic arthritis of the knee. There were technical complications in 13 patients (4%). In 157 patients (51%) pin-site infections were recorded; of these, 96% were minor and responded to wound toilet and antibiotic treatment. A total of 18 revision procedures was carried out

A retrospective review of 50 knees in 46 patients treated by arthroscopic removal of chondral flaps is reported. There was a relationship between the site of the flap and the type of symptoms; patellofemoral flaps produced anterior knee pain, posterior condylar flaps produced instability. At review after 18 to 36 months, after a second arthroscopy in eight cases, 44 of the 50 knees had retained significant improvement and 33 were symptom-free

The clinical and radiological features of 12 knees (10 patients) with congenital absence of the anterior cruciate ligament are presented. The high frequency of this condition in association with other more easily recognised congenital abnormalities of the knee is discussed. It is concluded that congenital absence of the anterior cruciate ligament is more common than generally suspected and is associated with other developmental abnormalities of both bone and soft tissue in the lower limb, particularly around the knee joint

Fifty patients who underwent a MacIntosh repair for anterolateral instability of the knee have been reviewed after a mean follow-up of two and a quarter years. The repair abolished a positive anterolateral jerk test in 42 out of 50 knees and at the time of review 37 patients (74 per cent) were involved in some form of active sport, having regained functional and clinical stability. The MacIntosh repair is described in detail and the importance of excluding meniscal lesions as the main cause of instability is emphasised

1. Eight patients are described in whom the patellae subluxated laterally on every extension of the knee. This is an unusual type of recurrent subluxation. It may recover completely, or remain symptom-free for many years, or increase in severity so that the patient seeks treatment for relief of pain and joint effusion, or progress to frank dislocation. 2. Each patient was examined and the probable causes were analysed. The bayonet deformity was present in twelve of the sixteen knees. A new observation is made on the relationship of tibial crest and tubercle in this condition

1 . Criticisms are expressed of previous reports on the use of intra-articular injections in the treatment of osteoarthritis of the knee. 2. A series of 181 patients with primary osteoarthritis of the knee treated by certain intra-articular injections is reported. Three solutions in common use were studied; normal saline and mock injections served as controls. 3. Irrespective of the injection used, including the controls, no significant difference in the effects was demonstrated in the results. 4. The place of intra-articular injection therapy in osteoarthritis is discussed. Attention is drawn to the psychological implications

A method of repair for anteromedial rotatory instability of the knee is described and the results of operations on 36 knees reviewed. Complete static correction occurred in 30 of these patients (84 per cent), three patients showed improvement (8 per cent) and three showed no improvement (8 per cent). Although the operation was not reliable as a correction for valgus instability, it did not increase this instability. This operation may be combined with other procedures to correct all instabilities or problems of the knee

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