1. The literature on hyperextension injuries of the spine is briefly reviewed. 2. Such injuries in the cervical spine can be subdivided into five groups based on the pathological anatomy, based on the experience of fifty-one patients in the Spinal Injuries Centre for Victoria over the past five years. 3. Extension injuries of the thoraco-lumbar spine are discussed. They are rare and have a poor prognosis. 4. The importance of treatment based on sound clinical and pathological knowledge is emphasised, particularly in order that stable and unstable lesions may be recognised early and managed correctly

Ankylosing spondylitis (AS) is a progressive multisystem chronic inflammatory disorder. The hallmark of this pathological process is a progressive fusion of the zygapophyseal joints and disc spaces of the axial skeleton, leading to a rigid kyphotic deformity and positive sagittal balance. The ankylosed spine is unable to accommodate normal mechanical forces, rendering it brittle and susceptible to injury. Traumatic hyperextension injury of the cervical spine leading to atlantoaxial subluxation (AAS) in AS patients can often be fatal. We report a non-traumatic mechanism of injury in AS progressing to AAS attributable to persistent hyperextension, which resulted in fatal migration of C2 through the foramen magnum. Cite this article: Bone Joint J 2013;95-B:206–9

1. The clinical and post-mortem findings are described of a patient who sustained a hyperextension injury of the neck with paraplegia. 2. There was no radiological evidence of fracture: osteoarthritis of the spine was present. 3. Evidence is presented that the cord was damaged from behind by the lamina of the vertebra below a tear in the anterior longitudinal ligament

1. The literature on paraplegia complicating hyperextension injuries of the cervical spine is reviewed, and the lack of any definite explanation of the mode of interference with cord function is noted. 2. A case is described in which a detailed dissection of the post-mortem specimen was carried out. On the basis of the findings it is suggested that one cause of the suppression of cord function in such injuries is thrombosis of the spinal arteries and liquefaction-necrosis of the cord

1) A case is reported of paraplegia with normal radiographic appearances in which cervical cord damage was shown at autopsy to have been due to hyperextension injury. 2) The mechanism of such injuries is discussed, together with the differential diagnosis from acute prolapse of an intervertebral disc. 3) The grave dangers of using the fully extended position of the cervical spine in the management of these cases is noted

Aims. Traumatic central cord syndrome (CCS) typically follows a hyperextension injury and results in motor impairment affecting the upper limbs more than the lower, with occasional sensory impairment and urinary retention. Current evidence on mortality and long-term outcomes is limited. The primary aim of this study was to assess the five-year mortality of CCS, and to determine any difference in mortality between management groups or age. Methods. Patients aged ≥ 18 years with a traumatic CCS between January 2012 and December 2017 in Wales were identified. Patient demographics and data about injury, management, and outcome were collected. Statistical analysis was performed to assess mortality and between-group differences. Results. A total of 65 patients were identified (66.2% male (n = 43), mean age 63.9 years (SD 15.9)). At a minimum of five years’ follow-up, 32.3% of CCS patients (n = 21) had died, of whom six (9.2%) had died within 31 days of their injury. Overall, 69.2% of patients (n = 45) had been managed conservatively. There was no significant difference in age between conservatively and surgically managed patients (p = 0.062). Kaplan-Meier analysis revealed no significant difference in mortality between patients managed conservatively and those managed surgically (p = 0.819). However, there was a significant difference in mortality between the different age groups (< 50 years vs 50 to 70 years vs > 70 years; p = 0.001). At five years’ follow-up, 55.6% of the patient group aged > 70 years at time of injury had died (n = 15). Respiratory failure was the most common cause of death (n = 9; 42.9%). Conclusion. Almost one-third of patients with a traumatic CCS in Wales had died within five years of their injury. The type of management did not significantly affect mortality but their age at the time of injury did. Further work to assess the long-term functional outcomes of surviving patients is needed to generate more reliable prognostic information. Cite this article: Bone Joint J 2023;105-B(8):920–927

We assessed hyperextension of the knee and joint laxity in 169 consecutive patients who underwent an anterior cruciate ligament reconstruction between 2000 and 2002 and correlated this with a selected number of age- and gender-matched controls. In addition, the mechanism of injury in the majority of patients was documented. Joint laxity was present in 42.6% (72 of 169) of the patients and hyperextension of the knee in 78.7% (133 of 169). All patients with joint laxity had hyperextension of their knee. In the control group only 21.5% (14 of 65) had joint laxity and 37% (24 of 65) had hyperextension of the knee. Statistical analysis showed a significant correlation for these associations. We conclude that anterior cruciate ligament injury is more common in those with joint laxity and particularly so for those with hyperextension of the knee

The success of total knee replacement (TKR) depends on optimal soft-tissue balancing, among many other factors. The objective of this study is to correlate post-operative anteroposterior (AP) translation of a posterior cruciate ligament-retaining TKR with clinical outcome at two years. In total 100 patients were divided into three groups based on their AP translation as measured by the KT-1000 arthrometer. Group 1 patients had AP translation < 5 mm, Group 2 had AP translation from 5 mm to 10 mm, and Group 3 had AP translation >  10 mm. Outcome assessment included range of movement of the knee, the presence of flexion contractures, hyperextension, knee mechanical axes and functional outcome using the Knee Society score, Oxford knee score and the Short-Form 36 questionnaire. At two years, patients in Group 2 reported significantly better Oxford knee scores than the other groups (p = 0.045). A positive correlation between range of movement and AP translation was noted, with patients in group 3 having the greatest range of movement (mean flexion: 117.9° (106° to 130°)) (p < 0.001). However, significantly more patients in Group 3 developed hyperextension > 10° (p = 0.01). In this study, the best outcome for cruciate-ligament retaining TKR was achieved in patients with an AP translation of 5 mm to 10 mm

Twenty-two cases of paraplegia complicating injury of the cervical column have been reviewed. The vertebral injury may be due to flexion or hyperextension violence. Flexion injury—There are three types of flexion injury: 1) dislocation; 2) compression fracture of a vertebral body; 3) acute retropulsion of an intervertebral disc. Evidence is presented in support of the view that disc protrusion is the cause of the cord lesion when there is no radiographic evidence of bone injury, and in some cases at least when there is a compression fracture. Treatment is discussed and the indications for caliper traction and laminectomy are presented. Hyperextension injurv—There are two types of hyperextension injury: 1) dislocation; 2) injury to arthritic spines. Hyperextension injury of an arthritic spine is the usual cause of paraplegia in patients over fifty years of age. The mechanism of hyperextension injury is described. The possible causes of spinal cord injury, and its treatment, are discussed

1. The claw position of a finger with intrinsic paralysis is caused by the blocking effect of the transverse lamina on the long extensor. This starts as soon as the metacarpo-phalangeal joint is hyperextended, and increases with further hyperextension. Thus the long extensor loses its pull on the interphalangeal joints and allows them to flex. Therefore, in intrinsic paralysis the claw position can be prevented or cured by keeping the metacarpo-phalangeal joint in flexion, however slight, which can be done by splinting, by tenodesis or by capsulorrhaphy. 2. Replacement of the intrinsics by some active element, although it may improve the action of the fingers, is not necessary for the correction of claw finger. The function of the intrinsics in the prevention of claw finger is not to be found in their extending effect on the interphalangeal joints, but in the flexion effect on the metacarpo-phalangeal joint, or at least in preventing its hyperextension. This is in accordance with the fact that loss of intrinsic function is disastrous only in supple fingers, in which the metacarpo-phalangeal joints tend to assume extreme degrees of hyperextension (Riordan 1953, Brand 1958). In such fingers, the wide range of hyperextension available at the metacarpo-phalangeal joints is, of course, part of a generalised laxity of the soft parts of the fingers. These soft parts generally tend to counteract the tendency to clawing; the less their resistance, the more the human finger as a whole will tend to behave like a musculo-articular model, and such a model without intrinsics will always immediately assume the claw position

We tested the hypothesis that children who sustain a supracondylar fracture have a greater range of elbow hyperextension than those with a fracture of the distal radius. Three observers made 358 measurements in 183 children (114 boys and 69 girls). There were 119 fractures of the distal radius and 64 supracondylar fractures. Initially, the group with a supracondylar fracture appeared to have extension 1.7° greater than that of the group with fracture of the distal radius. On average, there was a maximum variation of 3° between observers. After allowing for age, gender and observer, there was no significant difference between the groups. Our study had greater than 80% power to detect a difference in hyperextension of 2° at the 5% level with the above observer variability. When age and gender are taken into account, any variation in the amount of hyperextension at the elbow is not sufficient to explain the occurrence of a supracondylar fracture

Mechanical failure because of wear or fracture of the polyethylene tibial post in posteriorly-stabilised total knee replacements has been extensively described. In this study of 12 patients with a clinically and radiologically successful NexGen LPS posteriorly-stabilised prosthesis impingement of the anterior tibial post was evaluated in vivo in three dimensions during gait using radiologically-based image-matching techniques. Impingement was observed in all images of the patients during the stance phase, although the NexGen LPS was designed to accommodate 14° of hyperextension of the component before impingement occurred. Impingement arises as a result of posterior translation of the femur during the stance phase. Further attention must therefore be given to the configuration of the anterior portion of the femoral component and the polyethylene post when designing posteriorly-stabilised total knee replacements

Aims

The aim of this study was to evaluate the reliability and validity of a patient-specific algorithm which we developed for predicting changes in sagittal pelvic tilt after total hip arthroplasty (THA).

Thirty-three Monteggia fracture-dislocations occurring in patients aged 2 to 15 years were reviewed. A follow-up of 2 to 7 years in 25 patients revealed that 88% had good to excellent results and 12% had results which were fair or poor. Closed reduction was successful in 24 of 28 cases and appeared to be very effective. Open reduction was required only for older children or when treatment was begun late. A mild hyperextension deformity at the elbow noted on follow-up of patients with anterior dislocation of the radial head seemed to support the theory that the injury is caused by hyperextension. A new classification of Monteggia fracture-dislocations in children is proposed

1. The method of treatment of a mallet finger deformity by immobilisation in a plaster in the position of hyperextension of the distal interphalangeal joint and flexion of the proximal interphalangeal joint is, on the whole, unsatisfactory because the splint is difficult to apply, it may need to be changed frequently, and it is sometimes complicated by pressure sores. 2. In many cases the deformity is still present after six weeks of adequate immobilisation, but gradual improvement from the contraction of fibrous tissue occurs for up to six months. Therefore an assessment of the results of any method of treatment should be made only after an interval of at least six months. 3. The subjective end results at the end of six months are satisfactory whether or not there has been efficient immobilisation in hyperextension. Few patients have any disability and only rarely is this sufficient to cause interference with normal activities. A high proportion of patients show slight persistent deformity and limitation of movement, and this is seemingly uninfluenced appreciably by the type or duration of treatment. 4. The only treatment necessary for most cases of mallet finger is the application of elastic adhesive strapping or a straight spatula splint in order to relieve the initial discomfort from the injury

Initial treatment of traumatic spinal cord injury remains as controversial in 2023 as it was in the early 19th century, when Sir Astley Cooper and Sir Charles Bell debated the merits or otherwise of surgery to relieve cord compression. There has been a lack of high-class evidence for early surgery, despite which expeditious intervention has become the surgical norm. This evidence deficit has been progressively addressed in the last decade and more modern statistical methods have been used to clarify some of the issues, which is demonstrated by the results of the SCI-POEM trial. However, there has never been a properly conducted trial of surgery versus active conservative care. As a result, it is still not known whether early surgery or active physiological management of the unstable injured spinal cord offers the better chance for recovery. Surgeons who care for patients with traumatic spinal cord injuries in the acute setting should be aware of the arguments on all sides of the debate, a summary of which this annotation presents.

Cite this article: Bone Joint J 2023;105-B(4):347–355.

Between July 2000 and April 2004, 19 patients with bilateral spastic cerebral palsy who required an assistive device to walk had combined lengthening-transfer of the medial hamstrings as part of multilevel surgery. A standardised physical examination, measurement of the Functional Mobility Scale score and video or instrumented gait analysis were performed pre- and post-operatively. Static parameters (popliteal angle, flexion deformity of the knee) and sagittal knee kinematic parameters (knee flexion at initial contact, minimum knee flexion during stance, mean knee flexion during stance) were recorded. The mean length of follow-up was 25 months (14 to 45). Statistically significant improvements in static and dynamic outcome parameters were found, corresponding to improvements in gait and functional mobility as determined by the Functional Mobility Scale. Mild hyperextension of the knee during gait developed in two patients and was controlled by adjustment of their ankle-foot orthosis. Residual flexion deformity > 10° occurred in both knees of one patient and was treated by anterior distal femoral physeal stapling. Two children also showed an improvement of one level in the Gross Motor Function Classification System

Cadaveric knees replaced with the Geomedic, ICLH, Marmor and Total Condylar prostheses were tested in axial compression, in rotation and in hyperextension in order to observe the strength of fixation of the tibial components. In axial compression the strengths at failure varied widely, both with any one prosthesis and between prostheses. This is attributed largely to the strength of the cancellous bone of the tibia, which was measured in each case and also varied widely. Three natural knees failed at loads of 7300, 7600 and 8300 newtons respectively, whereas the strengths of replaced knees ranged from 3000 to 15750 newtons. At least one example of each design failed at less than 7300 newtons, suggesting little or no reserve of strength. The strength of fixation was greater when the tibial prosthesis was large enough to rest on the whole cross-section of the tibia. In rotation the three prostheses embodying rollers in troughs were stiffer than the Marmor which had a nearly flat tibial-bearing surface. The presence or absence of the cruciate ligaments had a negligible effect on torsional stiffness. In hyperextension, knees replaced with the ICLH, Marmor and Total Condylar prostheses failed by rupture of the posterior capsule at moments of about 60 newton-metres, compared with about 100 for natural knees. With the Marmor prosthesis the anterior cruciate ligament was avulsed at about 20 newton-metres compared with about 75 in natural knees, suggesting that in this respect the retention of the cruciate ligaments contributes little. None of the four knees tested after inserting a Geomedic prosthesis showed strengths as high as those replaced with the other three designs

1. The range of variation in full extension at the interphalangeal and metacarpo-phalangeal joints of the thumbs of 133 male and 100 female Europeans, and of 31 male Indians and 30 male Africans, has been investigated. 2. There is considerable variation between individuals in the maximum extension of both joints of the right and left thumbs in all groups studied. 3. The distribution for each joint in both thumbs in all groups is fairly symmetrical. 4. There is a high correlation between the right and left thumbs for both joints in all groups. 5. The mean angle of extension at the right and left metacarpo-phalangeal joints in all groups is similar. Female Europeans, however, show a significantly greater mean angle than male Europeans. 6. The mean interphalangeal angle of extension in male Europeans is significantly greater than that in female Europeans and the mean in the Indian and African groups is significantly greater than in the male European group. 7. There is slight negative correlation between the metacarpo-phalangeal angle and interphalangeal angle in each thumb in the European groups. 8. Many subjects in all groups can increase extension at the metacarpo-phalangeal joint after flexing the carpo-metacarpal joint. Marked hyperextension (over 40°) is more frequent in the left than in the right thumb, in females than in males, and in male Indians than in male Europeans and Africans. 9. Maximum extension at the interphalangeal joints is not related to the presence of a sesamoid bone in the anterior part of the capsule of the joint. 10. The surfaces of the metacarpo-phalangeal joints vary considerably in shape. Those which are flat form about 10 per cent. of the sample and do not show hyperextension. 11. The factors influencing the amount of extension at the interphalangeal joint is the degree of laxity of the anterior capsule. The problem at the metacarpo-phalangeal joint is more complex; both the capsule and the shape of the joint surfaces play important roles

Aims

Knowledge on total knee arthroplasties (TKAs) in patients with a history of poliomyelitis is limited. This study compared implant survivorship and clinical outcomes among affected and unaffected limbs in patients with sequelae of poliomyelitis undergoing TKAs.

Aims

Dual-mobility (DM) components are increasingly used to prevent and treat dislocation after total hip arthroplasty (THA). Intraprosthetic dissociation (IPD) is a rare complication of DM that is believed to have decreased with contemporary implants. This study aimed to report incidence, treatment, and outcomes of contemporary DM IPD.

Aims

Surgical approaches that claim to be minimally invasive, such as the direct anterior approach (DAA), are reported to have a clinical advantage, but are technically challenging and may create more injury to the soft-tissues during joint exposure. Our aim was to quantify the effect of soft-tissue releases on the joint torque and femoral mobility during joint exposure for hip resurfacing performed via the DAA.

Aims

Excessive posterior pelvic tilt (PT) may increase the risk of anterior instability after total hip arthroplasty (THA). The aim of this study was to investigate the changes in PT occurring from the preoperative supine to postoperative standing position following THA, and identify factors associated with significant changes in PT.

Injuries to the quadriceps muscle group are common in athletes performing high-speed running and kicking sports. The complex anatomy of the rectus femoris puts it at greatest risk of injury. There is variability in prognosis in the literature, with reinjury rates as high as 67% in the severe graded proximal tear. Studies have highlighted that athletes can reinjure after nonoperative management, and some benefit may be derived from surgical repair to restore function and return to sport (RTS). This injury is potentially career-threatening in the elite-level athlete, and we aim to highlight the key recent literature on interventions to restore strength and function to allow early RTS while reducing the risk of injury recurrence. This article reviews the optimal diagnostic strategies and classification of quadriceps injuries. We highlight the unique anatomy of each injury on MRI and the outcomes of both nonoperative and operative treatment, providing an evidence-based management framework for athletes.

Cite this article: Bone Joint J 2023;105-B(12):1244–1251.

1. Compression forces are mainly absorbed by the vertebral body. The nucleus pulposus, being liquid, is incompressible. The tense annulus bulges very little. On compression the vertebral end-plate bulges and blood is forced out of the cancellous bone of the vertebral body into the perivertebral sinuses. This appears to be the normal energy-dissipating mechanism on compression. 2. The normal disc is very resistant to compression. The nucleus pulposus does not alter in shape or position on compression or flexion. It plays no active part in producing a disc prolapse. On compression the vertebral body always breaks before the normal disc gives way. The vertebral end-plate bulges and then breaks, leading to a vertical fracture. If the nucleus pulposus has lost its turgor there is abnormal mobility between the vertebral bodies. On very gentle compression or flexion movement the annulus protrudes on the concave aspect–not on the convex side as has been supposed. 3. Disc prolapse consists primarily of annulus; it occurs only if the nucleus pulposus has lost its turgor. It then occurs very easily as the annulus now bulges like a flat tyre. 4. I have never succeeded in producing rupture of normal spinal ligaments by hyperextension or hyperflexion. Before rupture occurs the bone sustains a compression fracture. On the other hand horizontal shear, and particularly rotation forces, can easily cause ligamentous rupture and dislocation. 5. A combination of rotation and compression can produce almost every variety of spinal injury. In the cervical region subluxation with spontaneous reduction can be easily produced by rotation. If disc turgor is impaired this may occur with an intact anterior longitudinal ligament and explains those cases of tetraplegia without radiological changes or a torn anterior longitudinal ligament. The anterior longitudinal ligament can easily be ruptured by a rotation force and in my experience the so-called hyperextension and hyperflexion injuries are really rotation injuries. 6. Hyperflexion of the cervical spine or upper thoracic spine is an anatomical impossibility. In all spinal dislocations a body fracture may or may not occur with the dislocation, depending upon the degree of associated compression. In general, rotation forces produce dislocations, whereas compression forces produce fractures

Aims

Developmental cervical spinal stenosis (DcSS) is a well-known predisposing factor for degenerative cervical myelopathy (DCM) but there is a lack of consensus on its definition. This study aims to define DcSS based on MRI, and its multilevel characteristics, to assess the prevalence of DcSS in the general population, and to evaluate the presence of DcSS in the prediction of developing DCM.

We aim to explore the potential technologies for monitoring and assessment of patients undergoing arthroplasty by examining selected literature focusing on the technology currently available and reflecting on possible future development and application. The reviewed literature indicates a large variety of different hardware and software, widely available and used in a limited manner, to assess patients’ performance. There are extensive opportunities to enhance and integrate the systems which are already in existence to develop patient-specific pathways for rehabilitation.

Cite this article: Bone Joint J 2022;104-B(10):1104–1109.

Aims

Temporary epiphysiodesis (ED) is commonly applied in children and adolescents to treat leg length discrepancies (LLDs) and tall stature. Traditional Blount staples or modern two-hole plates are used in clinical practice. However, they require accurate planning, precise surgical techniques, and attentive follow-up to achieve the desired outcome without complications. This study reports the results of ED using a novel rigid staple (RigidTack) incorporating safety, as well as technical and procedural success according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework.

1. Three cases of anterior dislocation of the head of the radius associated with an undisplaced fracture of the olecranon are described. 2. A combination of pronation of the forearm and hyperextension of the elbow is suggested as a possible mechanism

Aims

Optimal exposure through the direct anterior approach (DAA) for total hip arthroplasty (THA) conducted on a regular operating theatre table is achieved with a standardized capsular releasing sequence in which the anterior capsule can be preserved or resected. We hypothesized that clinical outcomes and implant positioning would not be different in case a capsular sparing (CS) technique would be compared to capsular resection (CR).

Dynamic hyperextension of the big toe and supination of the forefoot may occur in the swing phase of walking in children with various neurological disorders. Symptoms arising from this have been successfully corrected in 13 feet of 11 children by transfer of extensor hallucis longus to the insertion of peroneus brevis

We describe a patient with traumatic right-sided invagination of two consecutive laminae into the spinal canal. The injury resembled a greenstick fracture and resulted in an acute Brown-Séquard syndrome. There was also an undisplaced hangman’s fracture of the axis vertebra. These injuries were caused by an acute hyperextension and axial compression of the cervical spine. Open reduction and internal fixation of the laminar fractures without fusion was followed by full neurological recovery within six weeks

1. From India a family is reported in which fifteen of fifty-seven were affected by the nail-patella syndrome. 2. Additional coincidental features not described previously were fiexion deformities of both hips and hyperextension of the interphalangeal joints of the fingers. 3. Patients affected by the condition do not always show the same blood group

We report our experience of surgical treatment for instability of flail knees after poliomyelitis in 228 patients. We made carefully selective use of soft-tissue release, extension osteotomy of the femur, and a patellar bone block for hyperextension. After six to nine years follow-up, 87% of the patients had retained significant improvement in stability and walking ability

The technique described aims to eliminate the drawbacks of the commonly accepted operative procedures for correction of the spastic "thumb-in-palm" deformity without fusion of the thumb. In all seven patients followed up for one and a half to two years after operation the thumb regained a functional position, being held out of the palm together with the metacarpal without hyperextension of the metacarpo-phalangeal joint

A case of cervical traumatic paraplegia is described in which there was no evidence of damage to vertebrae, discs or ligaments. Experimental evidence suggests that such injuries may be caused by inward bulging of the ligamentum flavum during hyperextension. The reasons why this inward bulging may occur, despite the elasticity of the ligamentum flavum, are discussed. Treatment of such cases is considered and the importance of avoiding extension emphasised

1. Six patients suffering from spontaneous posterior interosseous paralysis are described. 2. Two were due to benign tumour and four due to traumatic neuritis, three of which were associated with minor hyperextension injuries to the elbow joint and one with long standing cubitus varus. 3. Surgical exploration was performed in each patient with recovery of nerve function

1. A review of intra-articular and peri-articular fractures of the phalanges has been carried out, and the late results of such injuries have been examined. 2. These fractures usually unite by bone. 3. The results of conservative treatment by immobilisation are satisfactory in the case of mallet fractures, hyperextension sprain fractures and collateral avulsion fractures of the proximal phalanges. 4. The less satisfactory results after collateral avulsion fractures of the interphalangeal joints and avulsion fractures complicating dislocations are discussed

The case is reported of an elderly man with asymptomatic cervical spondylosis who sustained a minor hyperextension injury of the cervical spine when the brakes of a car were applied suddenly to avoid a collision. Within six hours marked swelling of the neck and severe dyspnoea developed, and a lateral radiograph showed the pharyngeal shadow displaced far forwards and a crack fracture of an anterior osteophyte. Tracheostomy and evacuation of a massive prevertebral haematoma were performed, with immediate relief. The case draws attention to the possibility of this serious complication of a "whiplash" type of injury

1. Pain in the elbow in javelin throwers is a common complaint. 2. The commonest type is caused by recurrent strain of the medial ligament. It develops in individuals who employ an incorrect throwing technique. The symptoms are cumulative, increasing with throwing and decreasing and resolving with rest. Treatment consists in improving the throwing technique. Local anaesthetic injected into the tender area produces complete but temporary relief. Hydrocortisone may produce partial or complete relief. 3. A second type of "javelin elbow" occurs in expert throwers and is the result of hyperextension of the elbow at the end of the throw, causing an injury to the tip of the olecranon. The symptoms are the result of a single throw or "mal-throw" and are completely disabling. They resolve with rest but tend to recur. If the tip of the olecranon is fractured excision of the fragment completely relieves the symptoms

Traumatic rupture of the tendon of the subscapularis muscle was documented as an isolated lesion in the shoulders of 16 men. The injury was caused either by forceful hyperextension or external rotation of the adducted arm. The patients complained of anterior shoulder pain and weakness of the arm when it was used above and below the shoulder level. They did not experience shoulder instability. The injured shoulders exhibited increased external rotation and decreased strength of internal rotation. A simple clinical manoeuvre called the 'lift-off test', reliably diagnosed or excluded clinically relevant rupture of the subscapularis tendon. Confirmation of the clinical diagnosis was best achieved by ultrasonography or MRI, but arthrography or CT arthrography were also useful. Surgical exploration confirmed the diagnosis in every case. Repair of the ruptured tendon was technically demanding and required good exposure to identify and protect the axillary nerve

The posterior cruciate ligament (PCL) was imaged by MRI throughout flexion in neutral tibial rotation in six cadaver knees, which were also dissected, and in 20 unloaded and 13 loaded living (squatting) knees. The appearance of the ligament was the same in all three groups. In extension the ligament is curved concave-forwards. It is straight, fully out-to-length and approaching vertical from 60° to 120°, and curves convex-forwards over the roof of the intercondylar notch in full flexion. Throughout flexion the length of the ligament does not change, but the separations of its attachments do. We conclude that the PCL is not loaded in the unloaded cadaver knee and therefore, since its appearance in all three groups is the same, that it is also unloaded in the living knee during flexion. The posterior fibres may be an exception in hyperextension, probably being loaded either because of posterior femoral lift-off or because of the forward curvature of the PCL. These conclusions relate only to everyday life: none may be drawn with regard to more strenuous activities such as sport or in trauma

1. Sixty feet operated upon either by triple or pantalar tarsal fusion for instability after poliomyelitis were re-examined ten to twenty-four years later. 2. After triple fusion with preservation of the ankle joint there was a striking absence of late osteoarthritis of the ankle, and only a low incidence of troublesome lateral instability of the ankle. The results were generally good provided the patient had reasonable power of extension of the knee. 3. Triple arthrodesis for completely flail foot in patients without active muscle control of the knee was often disappointing, so far as the limb as a whole was concerned, because of a persistent flexion deformity of the knee which usually necessitated the wearing of an appliance. 4. The results of pantalar arthrodesis for the flail foot were satisfactory. When this operation was performed (with the foot in slight equinus) in patients who lacked active extension of the knee it helped to stabilise the knee in walking by encouraging hyperextension

Seat-belt fractures of the lumbar spine in adolescents and adults are well recognised but there are few reports of these injuries in young children. We reviewed all seat-belt injuries in skeletally immature patients (Risser 0), seen at a tertiary referral centre between 1974 and 1991. There were ten cases, eight girls and two boys, with an average age of 7.5 years (3 to 13). Four distinct patterns of injury were observed, most commonly at the L2 to L4 level. Paraplegia, which is thought to be uncommon, occurred in three of our ten cases. Four children had intra-abdominal injuries requiring laparotomy. There was a delay in diagnosis either of the spinal or of the intra-abdominal injury in five cases, although all had contusion of the abdominal wall, the 'seat-belt sign'. Treatment of the fractures was conservative, by bed rest and then hyperextension casts. The incidence of this potentially devastating injury can be reduced by the optimal use of restraints, but there is often a delay in diagnosis. Our classification system may aid in the early detection and evaluation of this injury

We assessed narrowing of the spinal canal in 39 burst fractures and fracture-dislocations of thoracolumbar vertebrae treated by the AO Internal Spinal Fixator, using CT preoperatively and at various stages postoperatively. Computer-aided planimetry was used to measure the narrowing, and its restoration shortly after instrumentation, or at 15 months. The mean initial reduction of canal area was to 63.7% +/- 18.8% of normal; this was restored to a mean of 95.4% +/- 21.2% of normal when measured either soon after surgery or at 15 months (p < 0.001 for both groups). There was more improvement in cases assessed later. For fractures from D12 to L3, the mean canal area was restored to 99.4% of normal; but at L4 or L5 the mean restitution was to only 60.9% (p < 0.05). We found no correlation between preoperative loss of area and amount of restoration, or severity of neurological deficit. Nor was there any correlation between the delay before surgery and the improvement achieved. The mechanism of fracture reduction appears to be a combination of distraction ligamentotaxis and forced hyperextension

The fourth lumbar vertebrae and L4-5 discs from six cadaveric lumbar spines were subjected to detailed strain gauge analysis under conditions of controlled loading. With central compression loads, maximal compressive strain was found to occur near the bases of the pedicles and on both superficial and deep surfaces of the pars interarticularis, which emphasises the importance of the posterior elements of lumbar vertebrae in transmitting load. Radial bulge and tangential strain of the disc wall were maximal at the posterolateral surface, in agreement with the fact that disc degeneration and prolapse commonly occur there. Under posterior offset loads simulating extension, both compressive and tensile strains were found to be increased on both surfaces of the pars interarticularis, which suggests that hyperextension may lead to stress fractures and spondylolisthesis. Posterior offset loads also increased the radial bulge of the posterior disc wall and tangential strain at the anterior surface of the disc. Anterior offset loads simulating flexion increased the radial bulge of the anterior disc wall and tangential strain at the posterior surface of the disc. These findings are compatible with movement of the nucleus pulposus within the disc during flexion and extension. This hypothesis was supported by post-mortem discography

1. Thirty-three patients who had had stapling of the lower femoral and upper tibial epiphysis to correct inequality of the leg lengths were reviewed after maturity. The staples were inserted so that correction of the disparity would coincide with termination of growth. 2. The predicted corrections were found to be inaccurate. The error was 47 per cent in girls operated on between ten and twelve and 51 per cent in boys between ten and thirteen. In older children the prediction was more accurate. 3. Despite the inaccuracy of prediction only four patients were left with shortening of more than 3·5 centimetres. 4. Complications of the operation were deformity, ligamentous laxity, subjective symptoms and necessity for further operation. 5. Only one girl had a serious deformity–genu recurvatum of 25 degrees. Half the patients had minor degrees of hyperextension. 6. The causes of the complications are discussed and suggestions made how their incidence might be reduced. 7. It is concluded that the operation of stapling the epiphyses around the knee of the long leg has a small but useful part to play in the correction of inequality of leg lengths. It should be confined to tall boys over thirteen and girls over twelve

1 . The extensor assembly of the fingers consists of the central tendon joined by three pairs of components: a) the retinacular ligaments, which link the movements of the interphalangeal joints; b) the "wing" tendons, a lumbrical on the radial side, and usually a palmar interosseous on the ulnar side; c) the phalangeal tendons, usually dorsal interossei. 2. The retinacular ligaments are relaxed in full extension of the proximal interphalangeal joints and are, in this position, unable to extend the distal joints fully. This is because the interphalangeal joint surfaces are eccentric. 3. The pull of the wing tendons alters the shape of the extensor expansion and transfers the pull of the long extensor tendon from the base of the middle phalanx to the base of the distal phalanx, thus enabling full extension of the distal joint to be powerfully achieved. 4. The action of the lumbrical muscle, as an extensor of the interphalangeal joint, is demonstrated by a diagram showing its site and length in the various positions of the finger, calculated from the known excursions of the tendons. This is consistent with the observations on action potentials. 5. The phalangeal tendons of the dorsal interossei have a bifid insertion, a) into the phalangeal tubercle at the base of the proximal phalanx, and b) into the transverse band, and hence to the central tendon. The muscle acts at one or both of these attachments, according to the positions of the metacarpo-phalangeal and interphalangeal joints, in its varying functions of flexion, abduction and hyperextension. Finally an explanation of the deformity of clawing in ulnar palsy is given

Aims

Manipulation under anaesthesia (MUA) remains an effective intervention to address restricted range of motion (ROM) after total knee arthroplasty (TKA) and occurs in 2% to 3% of primary TKAs at our institution. Since there are few data on the outcomes of MUA with different anaesthetic methods, we sought to compare the outcomes of patients undergoing MUA with intravenous (IV) sedation and neuraxial anaesthesia.