1. By the use of a device that allows movement of a human finger joint to take place uninfluenced by muscle activity, the coefficient of friction has been determined between living articular surfaces. 2. The force of friction rises as the range of movement is increased, because of the tension then developing in the ligaments and the soft tissues surrounding the joint. 3. Measurements have also been made of the forces of friction within the ankle joint of the dog and within four types of reciprocating bearings (plastic, oil-lubricated, "floating" and hydrostatic). 4. By altering the load borne by the joints and bearings it has been shown that joints resemble in their behaviour those bearings in which a film of fluid is maintained between the fixed and moving surfaces, rather than bearings depending wholly or in part on boundary lubrication. 5. It is suggested that joints normally owe their great freedom of movement to a special type of fluid film lubrication that has been termed "weeping lubrication," supplemented by "floating lubrication," though on occasions boundary conditions may prevail

1 . Intertrochanteric osteotomy is valuable in the treatment of patients with osteoarthritis of the hip, giving a high percentage of satisfactory results. It often relieves the pain immediately, is long-lasting in its effects, and may even increase the range of movement. 2. There is no evidence from our figures that the extent of medial displacement of the lower fragment influences the result as judged from relief of pain, performance, and the patient's assessment. Movement, however, is less improved if displacement exceeds half the diameter of the divided bone. 3. Our observations did not support the view that improvement is caused by a changed relationship between the upper fragment and the acetabulum. When measurements were possible the position of the upper fragment usually remained virtually unaltered. 4. Our figures confirm that in most patients relief of pain is immediate; that is to say, the patient is aware on regaining consciousness that his pain has gone, even though he formerly had pain at rest. Whatever may be the mechanism that relieves the pain, it acts immediately

Displaced fractures of the forearm in children are often treated conservatively, but there is a relatively high incidence of redisplacement, malunion and consequent limitation of function. We have performed percutaneous Kirschner (K) wire fixation in 72 such children under the age of 14 years, of which 57 were reviewed for our study. Both the radius and ulna were fractured in 45 (79%), the radius only in eight and the ulna only in four. The mean initial angulation was 19° in the lateral plane and 9° in the anteroposterior plane for the radius and 15° and 9°, respectively, for the ulna. In 42 patients (74%) we performed closed reduction. In the remaining 15 (26%) closed reduction failed and an open reduction, through a minimal approach, was required before K wiring. At a mean follow-up of 20 months all patients had good functional results with an excellent range of movement. Only five had angulation of from 10° to 15° and none had nonunion, premature epiphyseal closure or deep infection. Percutaneous intramedullary K wiring for forearm diaphyseal fracture is a convenient, effective and safe operation, with minimal complications

We report the results of a prospective randomised trial which assessed the role of the posterior cruciate ligament (PCL) following total knee replacement (Genesis I; Smith and Nephew, Memphis, Tennessee). Over a four-year period, 211 patients underwent total knee replacement by the senior author (TJW). They were randomised at surgery to have the PCL either retained, excised or substituted with a posterior stabilised insert. If it was not possible to retain the ligament due to soft-tissue imbalance, it was released from its tibial insertion until suitable tension was obtained. This created a fourth group, those who were intended preoperatively to have the ligament retained, but in whom it was partially released as a result of findings at the time of surgery. All patients were evaluated using the Knee Society rating system (adapted from Insall). A total of 188 patients (212 knees) was available for follow-up at a mean of 3.5 years after surgery. Preoperatively, there was a varus deformity in 191 knees (90%) and a valgus deformity in 21 (10%). There were no statistical differences in the knee or function scores or the range of movement between the excised, retained and substituted groups. There were, however, significantly worse knee and function scores in the group in whom the PCL was released (p = 0.002)

Aims

Bone demonstrates good healing capacity, with a variety of strategies being utilized to enhance this healing. One potential strategy that has been suggested is the use of stem cells to accelerate healing.

1. A series of 149 consecutive cases of flexor tendon grafting in the fingers and thumb is reviewed and the results are analysed. A description of the technique which has evolved from this experience is given. 2. Replacement of a divided flexor digitorum profundus in the presence of an intact sublimis tendon restored a useful range of movement in 80 per cent of cases. 3. Replacement of both flexor digitorum profundus and sublimis gave good results in 70 to 80 per cent of cases. 4. Replacement of a divided flexor pollicis longus tendon gave good results in 85 per cent of cases. 5. The particular tendon used for the graft did not materially influence the result, but there are special indications for the use of the different tendons. 6. The choice of splintage or of early movement after operation does not appear to have a significant bearing upon the result. 7. The most important factor in determining the result is probably a precise and gentle surgical technique and complete haemostasis. Minor differences in method are of little importance. The failures in this series were due more to faulty performance of the operation than to any other single factor

We evaluated 242 consecutive fractures of the clavicle in adults which had been treated conservatively. Of these, 66 (27%) were originally in the middle third of the clavicle and had been completely displaced. We reviewed 52 of these patients at a mean of 38 months after injury. Eight of the 52 fractures (15%) had developed nonunion, and 16 patients (31%) reported unsatisfactory results. Thirteen patients had mild to moderate residual pain and 15 had some evidence of brachial plexus irritation. Of the 28 who had cosmetic complaints, only 11 considered accepting corrective surgery. No patient had significant impairment of range of movement or shoulder strength as a result of the injury. We found that initial shortening at the fracture of ≥20 mm had a highly significant association with nonunion (p < 0.0001) and the chance of an unsatisfactory result. Final shortening of 20 mm or more was associated with an unsatisfactory result, but not with nonunion. No other patient variable, treatment factor, or fracture characteristic had a significant effect on outcome. We now recommend open reduction and internal fixation of severely displaced fractures of the middle third of the clavicle in adult patients

We randomised 129 knees which were to be replaced using a standard posterior-cruciate-ligament (PCL)-retaining cemented total knee replacement into two groups. In one the PCL was retained in the normal way and in the other it was resected. They were well matched, with a predominance of women, and a mean age of 67 years. There was no statistically significant difference in the Hospital for Special Surgery scores at a mean of 57 months (56 to 60) between the two groups although 21 patients (24 knees) were lost to follow-up. Relief from pain, correction of deformity, range of movement, stability and strength were comparable in both. Radiological assessment showed femoral rollback in approximately 20% of knees with a slightly higher incidence in the PCL-resected group. There was no significant loosening detected in either group at review at two years. At five years, one knee in the PCL-retained group had been revised because of infection and one patient in each group was awaiting revision for loosening. Our findings have shown no significant difference in the five-year results for a PCL-retaining total knee replacement if the PCL is excised or preserved. This suggests two important points. First, the PCL is not functional in most patients with a total knee replacement even when retained. Secondly, patients with an excised PCL show a good result with a PCL-retaining implant, thereby questioning the need for a posterior stabilised design in such a situation

Aims

We aimed to address the question on whether there is a place for shoulder stabilization surgery in patients who had voluntary posterior instability starting in childhood and adolescence, and later becoming involuntary and uncontrollable.

Aims

Preoperative talar valgus deformity ≥ 15° is considered a contraindication for total ankle arthroplasty (TAA). We compared operative procedures and clinical outcomes of TAA in patients with talar valgus deformity ≥ 15° and < 15°.

We have assessed the influence of isolated and combined rotational malunion of the radius and ulna on the rotation of the forearm. Osteotomies were made in both the radius and the ulna at the mid-diaphyseal level of five cadaver forearms and stabilised with intramedullary metal implants. Malunion about the axis of the respective forearm bone was produced at intervals of 10°. The ranges of pronation and supination were recorded by a potentiometer under computer control. We examined rotational malunions of 10° to 80° of either the radius or ulna alone and combined rotational malunions of 20° to 60° of both the radius and ulna. Malunion of the ulna in supination had little effect on rotation of the forearm. Malunion of either the radius or of the ulna in pronation gave a moderate reduction of rotation of the forearm. By contrast, malunion of the radius in supination markedly reduced rotation of the forearm, especially with malunion greater than 60°. Combined rotational malunion produced contrasting results. A combination of rotational malunion of the radius and ulna in the same direction had an effect similar to that of an isolated malunion of the radius. A combination in the opposite direction gave the largest limitation of the range of movement. Clinically, rotational malunion may be isolated or part of a complex angular/rotational deformity and rotational malunion may lead to marked impairment of rotation of the forearm. A reproducible method for assessing rotational malunion is therefore needed

Between 1986 and 1990, we carried out 55 rotational acetabular osteotomies in 54 patients with acetabular dysplasia. Five hips were lost to follow-up. Of the 50 remaining, the degenerative changes were classified according to the criteria of Tönnis as grade 0 in 23, grade 1 in 16 and grade 2 in 11. The mean age of the three men and 46 women at the time of operation was 31.8 years (13 to 53). The mean follow-up was 137 months (120 to 174). At the most recent follow-up, 48 patients had satisfactory relief from pain. There was a slight decrease in the range of movement, particularly of flexion, in 18 hips. Radiologically, all osteotomies had united satisfactorily. There was radiological evidence of improvement in degenerative changes in 13 hips (5 grade 1 and 8 grade 2). Ten deteriorated (5 grade 0, 3 grade 1, and 2 grade 2) and one required total hip arthroplasty ten years after osteotomy. The osteoarthritis in the two hips with an associated valgus osteotomy progressed. The changes in radiological indices such as the centre-edge angle, acetabular femoral head index, acetabular root obliquity and horizontal or vertical displacement of the femoral head showed no statistical difference (unpaired Student’s t-test) between the patients with radiological progression and those with and without improvement

We studied 57 patients with isolated lunotriquetral injuries treated by arthrodesis, direct ligament repair, or ligament reconstruction. The outcomes were compared by using written questionnaires, the Disabilities of the Arm, Shoulder and Hand (DASH) score, range of movement, strength, morbidity and rates of reoperation. Isolated lunotriquetral injury was confirmed by arthroscopy or arthrotomy. The mean age of the patients was 30.7 years (15.4 to 53.7) and the injuries were subacute or chronic in 98.2%. Eight patients underwent lunotriquetral reconstruction using a distally-based strip of the tendon of extensor carpi ulnaris, 27 had lunotriquetral repair and 22 had lunotriquetral arthrodesis. The mean follow-up was 9.5 years (2 to 22). The probability of remaining free from complications at five years was 68.6% for reconstruction, 13.5% for repair, and less than 1% for arthrodesis. Of the lunotriquetral arthrodeses, 40.9% developed nonunion and 22.7% developed ulnocarpal impaction. The probability of not requiring further surgery at five years was 68.6% for reconstruction, 23.3% for repair and 21.8% for arthrodesis. The DASH scores for each group were not significantly different. Objective improvements in strength and movement, subjective indicators of pain relief and satisfaction were significantly higher in the lunotriquetral repair and reconstruction groups than in those undergoing arthrodesis

Survival analysis of joint replacement relies on the assumption that surgical procedures in patients lost to follow-up have the same chance of failing as those in patients who continue to be assessed. Our study questions that assumption. During the 16-year follow-up of 2268 patients who had received total hip replacements 142 (6%) were lost to follow-up. The cumulative loss at 15 years was 20%. At their last assessment, patients who subsequently failed to attend for follow-up had significantly worse pain, range of movement and opinion of their progress (p < 0.001) and significantly worse radiological features than a matched control group (p < 0.01). Patients lost to follow-up have a worse outcome than those who continue to be assessed. Consequently, a survival analysis that does not take into account such patients is likely to give falsely optimistic results. It is therefore essential that vigorous attempts are made to minimise loss to follow-up, and that the rate of such loss is quoted. The overall loss to follow-up disguises the magnitude of the problem, which is best quantified by a cumulative rate of follow-up. The reliability of a study can be assessed by a loss-to-follow-up quotient, calculated by the number of failures: the lower the quotient the more reliable the data. Ideally, the quotient should be less than 1

We reviewed 23 patients who had had 25 Darrach procedures for traumatic or post-traumatic disorders of the wrist at a mean follow-up of 75.5 months (36 to 121). The mean age at the time of operation was 61.1 years (34 to 82). All patients were reviewed in person. Assessment included a history, a questionnaire on patient satisfaction and a detailed physical examination. Standardised radiographs of both wrists were taken with the patient’s hands in a resting position and during maximal grip. Convergence of the distal ulnar stump towards the distal radius during maximal grip (dynamic radio-ulnar convergence) was seen in 14 wrists including five with actual contact (dynamic radio-ulnar impingement), but this produced symptoms in only two cases. The presence of dynamic radio-ulnar convergence did not correlate with grip strength, pinch strength, range of movement or wrist score, but was associated with increased length of excision of the distal ulna. Nineteen of the 23 patients were satisfied with the procedure. Dynamic radio-ulnar convergence is common after the Darrach procedure, but is rarely symptomatic; resection of the distal ulna remains a reliable procedure in the older patient with pain and loss of movement. Excision of the lower end of the ulna should be restricted to the least required to restore full rotation

Aims

The aim of this study was to identify risk factors for recurrent instability of the shoulder and assess the ability to return to sport in patients with engaging Hill-Sachs lesions treated with arthroscopic Bankart repair and Hill-Sachs remplissage (ABR-HSR).

We reviewed 236 of the 388 Chiari pelvic osteotomies performed between 1953 and 1967 at the Orthopaedic University Clinic of Vienna for the treatment of congenital dislocation and subluxation of the hip. Over 90% of the operations were performed by Chiari himself. Twenty-one hips had needed reoperation after an average of 15.4 years; the other 215 hips had been followed up for 20 to 34 years (mean 24.8). The overall clinical results were excellent or good in 51.4%, fair in 29.8% and poor in 18.3%. The results were worse with increasing age at operation. The Trendelenburg sign improved only in patients aged seven or less at operation, and range of movement decreased in all cases. Subjectively poor results were seen in patients with pre-operative signs of osteoarthritis. Radiological loss of correction during follow-up was seen only in cases with incomplete primary correction. The addition of an intertrochanteric varus osteotomy in 36 cases did not achieve either better centering or better development of the acetabular roof. Degenerative changes increased significantly during the long-term follow-up, but their progress seemed to have been slowed down by the osteotomy in the younger age groups. Indications and contra-indications for the operation are discussed

Many knee surgeons flex the knee and sometimes also extend the hip before inflating a tourniquet on the thigh. This practice stems from the belief that these manoeuvres prevent excessive strain on the quadriceps during surgery, the assumption being that movement of the muscle is restricted by an inflated tourniquet. We therefore examined, using ultrasound, the movement of the quadriceps muscle above and below the tourniquet before and after inflation. We applied a tourniquet of standard size to the thigh of five volunteers for approximately five minutes. A bubble of air was injected into the quadriceps muscle above the tourniquet and was the proximal point of reference. The musculotendinous junction was the distal point. The movement of the reference point was measured by ultrasound before and after inflation of the tourniquet. Each measurement was repeated with either the knee flexed and the hip extended, or the hip flexed and the knee extended. The mean and standard deviation were recorded. Before inflation the mean amount of passive movement was 1.1 ± 0.13 cm proximal and 4.0 ± 0.08 cm distal to the tourniquet, with a range of movement of the knee of 0° to 137° (6.7°). After inflation the mean passive movement was 1.0 ± 0.07 cm proximal and 4.0 ± 0.08 cm distal to the tourniquet with a range of 0° to 132° (± 7.6°). The ultrasound findings therefore have shown no evidence of restriction of the quadriceps muscle by an inflated tourniquet

The infrequency of serious cartilage destruction in the joints of children makes it probable that the majority will recover with antibiotic and constitutional treatment alone, especially if a joint biopsy is performed. Synovectomy for children should therefore be reserved for those whose knees remain swollen and warm, even after antibiotic therapy, or whose range of movement does not show signs of returning. Exploration of such joints may show that pannus is wholly or partly covering the cartilage and that it is soft and pitted. Removal of the pannus allows better nutrition of the cartilage. The number of children who require arthrodesis in the future should be very small. Adults who respond well to antibiotic and constitutional treatment may also recover without surgery, except biopsy, but for patients with more severe disease the need for an alternative to arthrodesis exists. The choice between synovectomy–better called joint clearance –can often only be made after the joint has been opened. The choice between the two operations has always been fully discussed with the patient before the operation. The results enumerated in this paper suggest that arthrodesis may only need to be performed for patients with severe disease, often involving the bony articular surfaces, and that joints may recover function even when there has been partial destruction of cartilage