We studied retrospectively a consecutive series of 547 shoulders in 529 patients undergoing operation for instability. In 41, the cause of instability was considered to be lateral avulsion of the capsule, including the inferior glenohumeral ligament, from the neck of the humerus, the HAGL lesion. In 35, the lesion was found at first exploration, whereas in six it was noted at revision of a previous failed procedure. In both groups, the patients were older on average than those with instability from other causes. Of the primary cases, in 33 (94.3%) the cause of the first dislocation was a violent injury; six (17.4%) had evidence of damage to the rotator cuff and/or the subscapularis. Only four (11.4%) had a Bankart lesion. In patients undergoing a primary operation in whom the cause of the first dislocation was a violent injury, who did not have a Bankart lesion and had no suggestion of multidirectional laxity, the incidence of HAGL was 39%

The type II Monteggia (posterior) lesion is a rare injury which is sometimes associated with ulnohumeral instability. We have reviewed 23 of 28 patients with this injury. A clinical and radiographic assessment was undertaken at follow-up. Functional outcome scores, including the Broberg and Morrey Index and the Disabilities of the Arm, Shoulder or Hand (DASH), were used. The results from the six patients with associated posterior ulnohumeral dislocation were compared with 17 without ulnohumeral injury. Those with dislocation had reduced movement of the elbow and had outcome scores indicative of greater disability compared to those without associated dislocation

Ligamentous instability of the ankle joint can be confirmed by radiographs taken in two planes. The place of the anteroposterior varus stress view is established, but the lateral view which shows anterior subluxation of the talus is frequently omitted. The anatomical significance of the two stress views has been determined by dividing different components of the lateral ligament of 20 cadaveric ankles and noting the subluxation that resulted from these procedures. A clinical assessment was then made of 54 ankles (46 patients) with radiological evidence of instability when subjected to varus and anterior stress. Anterior subluxation was found to be considerably more common than varus tilt, and it is therefore suggested that the lateral stress view should be an essential part of the investigation of the unstable ankle

We evaluated two reconstruction techniques for a simulated posterolateral corner injury on ten pairs of cadaver knees. Specimens were mounted at 30° and 90° of knee flexion to record external rotation and varus movement. Instability was created by transversely sectioning the lateral collateral ligament at its midpoint and the popliteus tendon was released at the lateral femoral condyle. The left knee was randomly assigned for reconstruction using either a combined or fibula-based treatment with the right knee receiving the other. After sectioning, laxity increased in all the specimens. Each technique restored external rotatory and varus stability at both flexion angles to levels similar to the intact condition. For the fibula-based reconstruction method, varus laxity at 30° of knee flexion did not differ from the intact state, but was significantly less than after the combined method. Both the fibula-based and combined posterolateral reconstruction techniques are equally effective in restoring stability following the simulated injury

We have evaluated the effect of the use of ultrasound in determining the initiation of treatment in neonatal instability of the hip. A total of 99 newborn infants (1.5% of all live births) with neonatal hip instability did not have treatment from birth, but were re-examined at eight to 15 days. In the 31 who had persisting clinical instability and ultrasound abnormality, treatment was then started with a Frejka pillow. The hips in the remaining 68 infants showed spontaneous clinical stabilisation and improvement of the ultrasound findings. Treatment was therefore withheld. There was a marked trend towards normal development in mildly unstable hips, whereas no hips with severe instability did so spontaneously. Further follow-up showed normal development in all the hips which had been treated, and in all except five of the 68 untreated infants. These five infants showed persistent hip dysplasia on both ultrasound and radiological examination at four to five months of age. Treatment with an abduction splint was then started and their hips developed normally. Ultrasound is very useful in deciding on treatment if the examiners have adequate experience with the method. Its use substantially reduces the rate of treatment. Spontaneous resolution occurred in more than half of the unstable hips. Since five of the untreated infants developed hip dysplasia a strict follow-up is essential to identify and treat these cases

In an unselected series of 55 cases of slipped capital femoral epiphysis (SCFE) we observed an incidence of 25% of epiphyseal reduction, mostly unintentional. Reduction indicated physeal instability and was associated with an effusion, detected by sonography on admission, and inability to bear weight. The true prevalence of instability may be higher since an effusion was noted in 33 cases (60%) on the initial sonographic assessment. Serial radiographs showed reduction in 12 (22%), with an average change of 15.1 degrees in the head-neck angle. Serial sonography showed reduction in 7 out of 20 cases (35%), with an average change of 3.7 mm in displacement. In two cases reduction was seen on sonography but not on radiography. Of the hips which showed subsequent reduction, 12 had had a bone scan on admission; three showed initial epiphyseal avascularity but only one progressed to symptomatic avascular necrosis. All stable hips had normal epiphyseal vascularity on the initial bone scan. This indicates the importance of injury from the initial displacement in causing avascular necrosis, rather than effusion, vascular compromise or iatrogenic injury from gentle repositioning. Physeal instability in SCFE is common and should be assessed clinically on admission. It is indicated by joint effusion or inability to bear weight. A slip is very unlikely to be unstable in a child able to bear weight and with no sonographic effusion

We reviewed the outcome of a retrospective case series of eight patients with atlantoaxial instability who had been treated by percutaneous anterior transarticular screw fixation and grafting under image-intensifier guidance between December 2005 and June 2008. The mean follow-up was 19 months (8 to 27). All eight patients had a solid C1–2 fusion. There were no breakages or displacement of screws. All the patients with pre-operative neck pain had immediate relief from their symptoms or considerable improvement. There were no major complications. Our preliminary clinical results suggest that percutaneous anterior transarticulation screw fixation is technically feasible, safe, useful and minimally invasive when using the appropriate instruments allied to intra-operative image intensification, and by selecting the correct puncture point, angle and depth of insertion

We have treated 45 patients (47 ankles) for chronic lateral instability by a new reconstructive procedure. The operation includes lateral shift of the entire lateral capsule-ligament complex and proximal advancement of the talocalcaneal ligament and the inferior extensor retinaculum. We reviewed 39 patients (39 ankles) at a mean of 4.6 years (2 to 7) after operation. There were 29 men and 10 women with an average age of 27 years (19 to 43); 11 of them were competitive college-level athletes and 28 were recreational athletes. The functional rating was excellent in 26 patients, good in 8, fair in 3 and poor in 2. Thirty-six patients (92%) were satisfied with the result and 34 (9 of 11 college-level athletes and 25 of 28 recreational athletes) have been able to return to their preinjury level of sport. At the last review, there had been only three episodes of recurrent ankle instability, all in recreational athletes; none had required further surgery. The unsatisfactory results were associated with pre-existing degenerative changes in the ankle

Forty-eight men and three women were reviewed an average of thirty-one months after pes anserinus transposition for chronic anteromedial rotational instability of the knee. Their ages ranged from eighteen to forty-two years (average twenty-five years). All but four of the injuries occurred during sport. The interval between injury and operation averaged thirty months. During this time twenty-three patients had had other operations of which eighteen were for excision of menisci. A further sixteen patients required excision of one or both menisci at the time of pes anserinus transposition. After operation large haematomata had to be expressed from four wounds. One patient had a pulmonary embolism All made a complete recovery. Worthwhile improvement of stability during activity was found in forty-two of the fifty-one knees. Pre-existing degeneration of articular cartilage associated with severe instability of long duration was the main cause of failure. Good motivation was important for success. Four grades of disability are described according to the severity of symptoms. It was found that a successful operation gave approximately one grade of improvement on this scale. Arthroscopy is recommended to identify torn menisci and degenerative changes before pes anserinus transposition is undertaken. An important advantage of this operation is its simplicity. When more elaborate ligamentous reconstructions are necessary for severe instability, pes anserinus transposition can be usefully added to complete the repair

We compared the rate of revision for instability after total hip replacement (THR) when lipped and non-lipped acetabular liners were used. We hypothesised that the use of a lipped liner in a modular uncemented acetabular component reduces the risk of revision for instability after primary THR. Using data from the New Zealand Joint Registry, we found that the use of a lipped liner was associated with a significantly decreased rate of revision for instability and for all other indications. Adjusting for the size of the femoral head, the surgical approach and the age and gender of the patient, this difference remained strongly significant (p < 0.001). We conclude that evidence from the New Zealand registry suggests that the use of lipped liners with modular uncemented acetabular components is associated with a decreased rate of revision for instability after primary THR. Cite this article: Bone Joint J 2014;96-B:884–8

The management of osteoarthritis of the knee associated with patellar instability secondary to external tibial torsion > 45° is challenging. Patellofemoral biomechanics in these patients cannot be achieved by intra-articular correction using standard techniques of total knee replacement. We reviewed seven patients (eight knees) with recurrent patellar dislocation and one with bilateral irreducible lateral dislocation who had undergone simultaneous total knee replacement and internal tibial derotational osteotomy. All had osteoarthritis and severe external tibial torsion. The mean follow-up was for 47.2 months (24 to 120). The mean objective and functional Knee Society scores improved significantly (p = 0.0001) from 29.7 and 41.5 pre-operatively to 71.4 and 73.5 post-operatively, respectively. In all patients the osteotomies healed and patellar stability was restored. Excessive external tibial torsion should be identified and corrected in patients with osteoarthritis and patellar instability. Simultaneous internal rotation osteotomy of the tibia and total knee replacement is a technically demanding but effective treatment for such patients

Using roentgen stereophotogrammetry we have recorded the three-dimensional movements of the knee during an anteroposterior laxity test in 36 patients with torn anterior cruciate ligaments and in three cadaver knees. At 30 degrees of knee flexion and before loads were applied the tibia occupied a more laterally rotated position if the anterior cruciate ligament had been injured. When the tibia was pulled anteriorly knees with cruciate deficiency rotated more laterally and were more abducted than normal knees. Posterior traction induced lateral rotation in the injured knee and medial rotation in the intact one. Precise knowledge of the three-dimensional instability of the anterior cruciate deficient knee may be important when the laxity is evaluated only in relation to one of the three cardinal axes

In a prospective study conducted between 1990 and 1997, 24 101 newborn infants were examined for neonatal instability of the hip and classified by the ethnic origin of their parents. In 63% their mother and father were of Swedish extraction and in 24% they were born in a foreign country. Those of foreign extraction were split into ethnic and geographical subgroups. Although the incidence of treated (dislocatable-unstable) hips was greater in Swedes (7.6‰), than in other geographical groups (5.8‰) it was not significantly different (p = 0.065). A total of 12.7‰ were referred from the neonatal ward to the orthopaedic clinic with suspected dislocatable or unstable hips; 6.8‰ were treated (5.4‰ dislocatable, 1.4‰ unstable), but 5.9‰ were not treated since their ultrasound examination was normal. Two hips were diagnosed late and one case of mild avascular necrosis was found. Examination by dynamic ultrasound decreased the number of treated cases by 5.9‰ but was not an absolute guarantee of diagnosis

In 28 patients with a solitary diagnosis of instability of the trapeziometacarpal joint because of a rupture of the anterior oblique ligament, reconstruction was carried out using a slip of the tendon of flexor carpi radialis. We were able to review 26 patients. The results after a follow-up of four years seven months showed that most (87%) had significant relief from pain and symptoms. Seventeen were graded as good to excellent. The mean grip strength recovered to 86% of the contralateral side. Most patients (81%) felt that they had subjective improvement and would have undergone the operation again. A lesser functional result was seen in those who developed a flexion deformity because of overtightening of the reconstruction. Increased awareness of this lesion can lead to an early and clear diagnosis so that the patient may be advised adequately. We describe a specific, diagnostic, clinical test which we have used consistently and successfully

We reviewed 32 ankles in 30 patients at an average of five years after a Watson-Jones tenodesis. All but one patient had had ankle pain before operation and 19 had had clicking, catching, or locking of the ankle. Eleven of these had an ankle arthrotomy at the time of ligament reconstruction for intraarticular pathology. At review seven of 23 ankles had a significant decrease in ankle motion, and five in subtalar motion, but only two were unstable on examination. Twenty-one ankles, however, caused some pain on activity and nine were tender on palpation. These findings indicate intra-articular degeneration or injury rather than simple instability. Radiographs of 16 ankles showed good varus and anterior-drawer stability. Seven had talocrural osteoarthritis, but only four showed grade-1 subtalar osteoarthritis. We found no correlation between follow-up time and long-term results. The Watson-Jones tenodesis provides good rotational and lateral ankle instability and does not appear to lead to subtalar degeneration

1. The clinical features in nineteen patients with structural defects of the pars interarticularis are compared with the findings in twenty-two patients with degenerative changes in the lumbar spine, and are shown to be essentially the same. 2. It is suggested that both structural defects and degenerative changes give rise to mechanical instability of the lumbar spine. This puts an increased load on the posterior vertebral soft tissues and gives rise to a characteristic picture, the features of which are described. 3. The signs and symptoms of root compression may be superimposed on this picture, and when this is the case, decompression of the nerve roots should be undertaken in addition to spinal fusion, which is suggested as the logical treatment. 4. After fusion, with decompression when indicated, 50 per cent of the patients were completely relieved of their symptoms and 87 per cent derived worthwhile benefit

Objectives. To evaluate the applicability of MRI for the quantitative assessment of anterior talofibular ligaments (ATFLs) in symptomatic chronic ankle instability (CAI). Methods. Between 1997 and 2010, 39 patients with symptomatic CAI underwent surgical treatment (22 male, 17 female, mean age 25.4 years (15 to 40)). In all patients, the maximum diameters of the ATFLs were measured on pre-operative T2-weighted MR images in planes parallel to the path of the ATFL. They were classified into three groups based on a previously published method with modifications: ‘normal’, diameter = 1.0 - 3.2 mm; ‘thickened’, diameter > 3.2 mm; ‘thin or absent’, diameter < 1.0 mm. Stress radiography was performed with the maximum manual force in inversion under general anaesthesia immediately prior to surgery. In surgery, ATFLs were macroscopically divided into two categories: ‘thickened’, an obvious thickened ligament and ‘thin or absent’. The imaging results were compared with the macroscopic results that are considered to be of a gold standard. Results. Agreement was reached when comparison was made between groups, based on MRI and macroscopic findings. ATFLs were abnormal in all 39 cases and classified as ten ‘thickened’ and 29 ‘thin or absent’. As to talar tilt stress radiography, a clear cut-off angle, which would allow discrimination between ‘thickened’ and ‘thin or absent’ patients, was not identified. Conclusion. MRI is valuable as a pre-operative assessment tool that can provide the quantitative information of ATFLs in patients with CAI. Cite this article Bone Joint Res 2014;3:241–5

Fifty-five patients with severe pain from spinal instability secondary to metastatic cancer were referred to Hope Hospital, none being judged to be in a terminal condition. One patient had too extensive disease for surgery so 54 were treated by 55 spinal stabilisations; 49 obtained complete relief of pain and two had partial relief. There were three failures. Twenty-eight of the patients had clinical evidence of spinal cord or cauda equina compression and were decompressed at the time of stabilisation. Of these, 20 had major recovery of neurological function. Patients with pre-operative evidence of extradural tumour had 'prophylactic' decompression at the time of stabilisation; none of these patients later developed signs of cord or cauda equina compression. The results suggest that alleviation of pain and restoration of mobility are best achieved by segmental spinal stabilisation; a few patients require a combined anterior and posterior stabilisation. Postoperative radiotherapy should be given whenever possible, and the causative tumour should be treated by endocrine or chemotherapy, as indicated

Instability may present at a different level after successful stabilisation of an unstable segment in apparently isolated injuries of the cervical spine. It can give rise to progressive deformity or symptoms which require further treatment. We performed one or more operations for unstable cervical spinal injuries on 121 patients over a period of 90 months. Of these, five were identified as having instability due to an initially unrecognised fracture-subluxation at a different level. We present the details of these five patients and discuss the problems associated with their diagnosis and treatment

We have reviewed 104 patients who had partial resection of the fibula for use as a graft. Only 44 were completely free from symptoms, and six had developed significant ankle instability which had required reconstruction by a sliding graft. This procedure successfully restored ankle stability in all six cases