1 . Two cases of chronic progressive dislocation of the talo-navicular joints are discussed. 2. Radiographs are presented showing the development of the lesions over a period of eighteen years. 3. It is thought that the lesion is caused by laxity of ligaments and subsequent osteoarthritic changes

Aims

It is unknown whether kinematic alignment (KA) objectively improves knee balance in total knee arthroplasty (TKA), despite this being the biomechanical rationale for its use. This study aimed to determine whether restoring the constitutional alignment using a restrictive KA protocol resulted in better quantitative knee balance than mechanical alignment (MA).

The role of flexible carbon-fibre implants as substitutes for injured tendons and ligaments was investigated. These implants were simple to perform and were well tolerated by the patient. Repairs using carbon-fibres in 60 patients were successful, particularly in the almost insoluble problem of posterior cruciate laxity. The results in this report show that carbon-fibre implants have few disadvantages and have a future use in reconstructive procedures

1. Thirty-two infants with genu recurvatum congenitum are reported. 2. Fifteen infants responded completely within eight weeks with conservative treatment; the remaining cases were recalcitrant. 3. The etiology, pathology and treatment of the two groups are discussed. 4. The prognosis is adversely affected by delay in treatment by the presence of certain associated deformities and by generalised joint laxity. 5. Indications for operative treatment are suggested

1. The pathogenesis of recurrent anterior dislocation of the shoulder has been studied at operation and by experiments on cadavers. 2. Lesions of the subscapularis muscle leading to lengthening and laxity have been demonstrated. 3. This lengthening is the prime factor in producing instability of the shoulder; capsular and bony defects are no more than subsidiary causes. 4. Good results have been obtained by a procedure based on this theory of etiology

We set up a trial to test whether the KT1000 arthrometer would give consistent measurements of anteroposterior laxity when used by the same and different examiners on the knees of the same subjects on the same day. The results showed substantial inter- and intra-examiner variation in the measurements both of absolute displacement in single knees and of side-to-side differences between pairs of knees. This casts doubt on the reliability of the instrument when used to compare the results of different techniques for reconstructing injured cruciate ligaments

The modified Magnuson-Stack procedure of lateral and distal transfer of the insertion of the subscapularis muscle was used in 38 consecutive patients with recurrent anterior dislocation of the shoulder, all of whom have been followed-up for a minimum of three years. There was only one failure; the other 37 patients had an excellent or satisfactory result with an adequate range of movement. Bankart and Hill-Sachs lesions were not a constant finding but subscapularis laxity was detected in almost every case, an observation that helps to confirm its central role as a cause of recurrence

Aims

Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function.

Experiments were carried out to determine the optimum conformity between the femoral and tibial condyles in condylar replacement knee prostheses. Wear tests and observations from removed prostheses indicated that both high and low conformity produced characteristic abrasion and fatigue. Partly conforming condyles provided stability under load-bearing but allowed laxity to occur. Fixation to resist the various forces on the tibial components was enhanced by a short central intramedullary peg. Partial conformity is proposed as the optimum configuration between femoral and tibial components

1. Congenital dislocation of the hip can be diagnosed clinically immediately after birth and the diagnosis confirmed radiologically by a special technique. 2. If the affected joint is reduced during the first two or three days after birth and held reduced for a period not exceeding three months, the joint will remain stable. 3. This treatment probably leads to normal development of the hip joint. 4. The cause of congenital dislocation of the hip may be laxity of the soft tissues of the joint and not a primary dysplasia of the acetabulum

From 1970 to 1978, 29 patients had a unilateral operation for bilateral recurrent dislocation of the patella. We examined 21 of them at a mean of 14 years postoperatively. Eighteen of these patients had evidence of generalised joint laxity. Six of the operated knees and four of the unoperated knees still had recurrent dislocations. The operated knees were clinically worse, with a significantly higher incidence of osteoarthritis. We concluded that the operations used to treat recurrent dislocation of the patella may have had short-term benefits, but did not cure the patients in the long term

A logical, objective and reproducible grading system for the pivot shift test is proposed. The rationale is based on performing the examination in varying positions of rotation of the tibia, allowing the type and degree of the different laxities to be defined and quantified. The system has been assessed against a new "unblocked" test for anterior subluxation and against radiographic measurements, operative findings and results. This grading system can be valuable in pre-operative assessment and planning and its use in postoperative evaluation would enable results from different centres and different procedures to be compared more accurately

We studied 100 fresh human shoulders in cadavers (mean age 76 years), and the range of passive abduction (RPA) in 100 volunteers with normal shoulders and in 90 patients with instability of the joint, over a period of six years. The anatomical and clinical findings showed that passive abduction occurs within the glenohumeral joint only, is controlled by the inferior glenohumeral ligament and has a constant value in 95% of both shoulders in normal subjects. In patients with instability, 85% showed an RPA of over 105° with 90° in the contralateral shoulder. In the remaining patients a strongly positive apprehension test suggested a diagnosis of instability. An RPA of more than 105° is associated with lengthening and laxity of the inferior glenohumeral ligament

The anteroposterior stability of cadaveric knees was investigated. There was a wide range of normal laxity; knees were more stable at 90 degrees than at 20 degrees flexion. Anterior cruciate ligament implants with different stiffnesses were inserted; normal stability could always be restored, and the stiffness or extensibility of implants did not affect knee behaviour significantly. The tightness of implants was critical--small tensioning errors caused subluxation, inhibited knee extension and allowed damagingly high implant tensions. It is concluded that the tension of ligament implants could not be adjusted simply with a pre-set instrument; the procedure will remain critically dependent on the judgment of the operating surgeon

Varus and valgus joint laxity of the normal living knee in flexion was assessed using MRI. Twenty knees were flexed to 90° and were imaged in neutral and under a varus-valgus stress in an open MRI system. The configuration of the tibiofemoral joint gap was studied in slices which crossed the epicondyles of the femur. When a varus stress was applied, the lateral joint gap opened by 6.7 ± 1.9 mm (mean ± . sd. ; 2.1 to 9.2) whereas the medial joint gap opened by only by a mean of 2.1 ± 1.1 mm (0.2 to 4.2). These discrepancies indicate that the tibiofemoral flexion gap in the normal knee is not rectangular and that the lateral joint gap is significantly lax. These results may be useful for adequate soft-tissue balancing and bone resection in total knee arthroplasty and reconstruction surgery on ligaments