Treatment of high-grade limb bone sarcoma that invades a joint requires en bloc extra-articular excision. MRI can demonstrate joint invasion but is frequently inconclusive, and its predictive value is unknown. We evaluated the diagnostic accuracy of direct and indirect radiological signs of intra-articular tumour extension and the performance characteristics of MRI findings of intra-articular tumour extension. We performed a retrospective case-control study of patients who underwent extra-articular excision for sarcoma of the knee, hip, or shoulder from 1 June 2000 to 1 November 2020. Radiologists blinded to the pathology results evaluated preoperative MRI for three direct signs of joint invasion (capsular disruption, cortical breach, cartilage invasion) and indirect signs (e.g. joint effusion, synovial thickening). The discriminatory ability of MRI to detect intra-articular tumour extension was determined by receiver operating characteristic analysis.Aims
Methods
The aim of this study was to evaluate the diagnostic accuracy of the absolute synovial polymorphonuclear neutrophil cell (PMN) count for the diagnosis or exclusion of periprosthetic joint infection (PJI) after total hip (THA) or knee arthroplasty (TKA). In this retrospective cohort study, 147 consecutive patients with acute or chronic complaints following THA and TKA were included. Diagnosis of PJI was established based on the 2018 International Consensus Meeting criteria. A total of 39 patients diagnosed with PJI (32 chronic and seven acute) and 108 patients with aseptic complications were surgically revised.Aims
Methods
Aims. Staphylococcus aureus is a major cause of septic arthritis, and in vitro studies suggest α haemolysin (Hla) is responsible for chondrocyte death. We used an in vivo murine joint model to compare inoculation with wild type S. aureus 8325-4 with a Hla-deficient strain DU1090 on chondrocyte viability, tissue histology, and joint biomechanics. The aim was to compare the actions of S. aureus Hla alone with those of the animal’s immune response to infection. Methods. Adult male C57Bl/6 mice (n = 75) were randomized into three groups to receive 1.0 to 1.4 × 10. 7. colony-forming units (CFUs)/ml of 8325-4, DU1090, or saline into the right stifle joint. Chondrocyte death was assessed by confocal microscopy. Histological changes to inoculated joints were graded for inflammatory responses along with gait, weight changes, and limb swelling. Results. Chondrocyte death was greater with 8325-4 (96.2% (SD 5.5%); p < 0.001) than DU1090 (28.9% (SD 16.0%); p = 0.009) and both were higher than controls (3.8% (SD 1.2%)). Histology revealed cartilage/bone damage with 8325-4 or DU1090 compared to controls (p = 0.010). Both infected groups lost weight (p = 0.006 for both) and experienced limb swelling (p = 0.043 and p = 0.018, respectively).
The preoperative diagnosis of periprosthetic joint infection (PJI) remains a challenge due to a lack of biomarkers that are both sensitive and specific. We investigated the performance characteristics of polymerase chain reaction (PCR), interleukin-6 (IL6), and calprotectin of synovial fluid in the diagnosis of PJI. We performed systematic search of PubMed, Embase, The Cochrane Library, Web of Science, and Science Direct from the date of inception of each database through to 31 May 2021. Studies which described the diagnostic accuracy of synovial fluid PCR, IL6, and calprotectin using the Musculoskeletal Infection Society criteria as the reference standard were identified.Aims
Methods
This study aimed to answer two questions: what are the best diagnostic methods for diagnosing bacterial arthritis of a native joint?; and what are the most commonly used definitions for bacterial arthritis of a native joint? We performed a search of PubMed, Embase, and Cochrane libraries for relevant studies published between January 1980 and April 2020. Of 3,209 identified studies, we included 27 after full screening. Sensitivity, specificity, area under the curve, and Youden index of diagnostic tests were extracted from included studies. We grouped test characteristics per diagnostic modality. We extracted the definitions used to establish a definitive diagnosis of bacterial arthritis of a native joint per study.Aims
Methods
To report early (two-year) postoperative findings from a randomized controlled trial (RCT) investigating disease-specific quality of life (QOL), clinical, patient-reported, and radiological outcomes in patients undergoing a total shoulder arthroplasty (TSA) with a second-generation uncemented trabecular metal (TM) glenoid versus a cemented polyethylene glenoid (POLY) component. Five fellowship-trained surgeons from three centres participated. Patients aged between 18 and 79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Patients were randomized intraoperatively to either a TM or POLY glenoid component. Study intervals were: baseline, six weeks, six-, 12-, and 24 months postoperatively. The primary outcome was the Western Ontario Osteoarthritis Shoulder QOL score. Radiological images were reviewed for metal debris. Mixed effects repeated measures analysis of variance for within and between group comparisons were performed.Aims
Methods
Periprosthetic hip and knee infection remains one of the most severe complications following arthroplasty, with an incidence between 0.5% to 1%. This study compares the outcomes of revision surgery for periprosthetic joint infection (PJI) following hip and knee arthroplasty prior to and after implementation of a specialist PJI multidisciplinary team (MDT). Data was retrospectively analyzed from a single centre. In all, 29 consecutive joints prior to the implementation of an infection MDT in November 2016 were compared with 29 consecutive joints subsequent to the MDT conception. All individuals who underwent a debridement antibiotics and implant retention (DAIR) procedure, a one-stage revision, or a two-stage revision for an acute or chronic PJI in this time period were included. The definition of successfully treated PJI was based on the Delphi international multidisciplinary consensus.Aims
Methods
This study aims to describe the pre- and postoperative self-reported health and quality of life from a national cohort of patients undergoing elective total conventional hip arthroplasty (THA) and total knee arthroplasty (TKA) in Australia. For context, these data will be compared with patient-reported outcome measures (PROMs) data from other international nation-wide registries. Between 2018 to 2020, and nested within a nationwide arthroplasty registry, preoperative and six-month postoperative PROMs were electronically collected from patients before and after elective THA and TKA. There were 5,228 THA and 8,299 TKA preoperative procedures as well as 3,215 THA and 4,982 TKA postoperative procedures available for analysis. Validated PROMs included the EuroQol five-dimension five-level questionnaire (EQ-5D-5L; range 0 to 100; scored worst-best health), Oxford Hip/Knee Scores (OHS/OKS; range 0 to 48; scored worst-best hip/knee function) and the 12-item Hip/Knee disability and Osteoarthritis Outcome Score (HOOS-12/KOOS-12; range 0 to 100; scored best-worst hip/knee health). Additional items included preoperative expectations, patient-perceived improvement, and postoperative satisfaction. Descriptive analyses were undertaken.Aims
Methods
Tenosynovial giant cell tumour (TGCT) is one of the most common soft-tissue tumours of the foot and ankle and can behave in a locally aggressive manner. Tumour control can be difficult, despite the various methods of treatment available. Since treatment guidelines are lacking, the aim of this study was to review the multidisciplinary management by presenting the largest series of TGCT of the foot and ankle to date from two specialized sarcoma centres. The Oxford Tumour Registry and the Leiden University Medical Centre Sarcoma Registry were retrospectively reviewed for patients with histologically proven foot and ankle TGCT diagnosed between January 2002 and August 2019.Aims
Methods
Osteonecrosis (ON) can cause considerable morbidity in young people who undergo treatment for acute lymphoblastic leukaemia (ALL). The aims of this study were to determine the operations undertaken for ON in this population in the UK, along with the timing of these operations and any sequential procedures that are used in different joints. We also explored the outcomes of those patients treated by core decompression (CD), and compared this with conservative management, in both the pre- or post-collapse stages of ON. UK treatment centres were contacted to obtain details regarding surgical interventions and long-term outcomes for patients who were treated for ALL and who developed ON in UKALL 2003 (the national leukaemia study which recruited patients aged 1 to 24 years at diagnosis of ALL between 2003 and 2011). Imaging of patients with ON affecting the femoral head was requested and was used to score all lesions, with subsequent imaging used to determine the final grade. Kaplan-Meier failure time plots were used to compare the use of CD with non surgical management.Aims
Methods
Microbiological culture is a key element in the diagnosis of periprosthetic joint infection (PJI). However, cultures of periprosthetic tissue do not have optimal sensitivity. One of the main reasons for this is that microorganisms are not released from the tissues, either due to biofilm formation or intracellular persistence. This study aimed to optimize tissue pretreatment methods in order to improve detection of microorganisms. From December 2017 to September 2019, patients undergoing revision arthroplasty in a single centre due to PJI and aseptic failure (AF) were included, with demographic data and laboratory test results recorded prospectively. Periprosthetic tissue samples were collected intraoperatively and assigned to tissue-mechanical homogenization (T-MH), tissue-manual milling (T-MM), tissue-dithiothreitol (T-DTT) treatment, tissue-sonication (T-S), and tissue-direct culture (T-D). The yield of the microbial cultures was then analyzed.Aims
Methods
We have encountered patients who developed large joint fluid collections with massive elevations in chromium (Cr) and cobalt (Co) concentrations following metal-on-metal (MoM) hip arthroplasties. In some cases, retrieval analysis determined that these ion concentrations could not be explained simply by the wear rates of the components. We hypothesized that these effects may be associated with aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL). We examined the influence of the ALVAL grade on synovial fluid Co and Cr concentrations following adjustment for patient and device variables, including volumetric wear rates. Initially restricting the analysis to include only patients with one MoM hip resurfacing device, we performed multiple regression analyses of prospectively collected data. We then repeated the same statistical approach using results from a larger cohort with different MoM designs, including total hip arthroplasties.Objectives
Patients and Methods
Tuberculosis (TB) infection of bones and joints accounts for
6.7% of TB cases in England, and is associated with significant
morbidity and disability. Public Health England reports that patients
with TB experience delays in diagnosis and treatment. Our aims were
to determine the demographics, presentation and investigation of
patients with a TB infection of bones and joints, to help doctors
assessing potential cases and to identify avoidable delays. This was a retrospective observational study of all adults with
positive TB cultures on specimens taken at a tertiary orthopaedic
centre between June 2012 and May 2014. A laboratory information
system search identified the patients. The demographics, clinical presentation,
radiology, histopathology and key clinical dates were obtained from
medical records.Aims
Patients and Methods
To evaluate the effectiveness of an institutionally developed
algorithm for evaluation and diagnosis of prosthetic joint injection
and to determine the impact of this protocol on overall hospital
re-admissions.p We retrospectively evaluated 2685 total hip arthroplasty (THA)
and total knee arthroplasty (TKA) patients prior to (1263) and following
(1422) the introduction of an infection detection protocol. The
protocol used conservative thresholds for C-reactive protein to
direct the medical attendant to aspirate the joint. The protocol
incorporated a clear set of laboratory and clinical criteria that
allowed a patient to be discharged home if all were met. Patients were
included if they presented to our emergency department within 120
days post-operatively with concerns for swelling, pain or infection
and were excluded if they had an unambiguous infection or if their
chief complaint was non-orthopaedic in nature.Aims
Patients and Methods
The high revision rates of the DePuy Articular Surface Replacement (ASR) and the DePuy ASR XL (the total hip arthroplasty (THA) version) have led to questions over the viability of metal-on-metal (MoM) hip joints. Some designs of MoM hip joint do, however, have reasonable mid-term performance when implanted in appropriate patients. Investigations into the reasons for implant failure are important to offer help with the choice of implants and direction for future implant designs. One way to assess the performance of explanted hip prostheses is to measure the wear (in terms of material loss) on the joint surfaces. In this study, a coordinate measuring machine (CMM) was used to measure the wear on five failed cementless Biomet Magnum/ReCap/ Taperloc large head MoM THAs, along with one Biomet ReCap resurfacing joint. Surface roughness measurements were also taken. The reason for revision of these implants was pain and/or adverse reaction to metal debris (ARMD) and/or elevated blood metal ion levels.Objectives
Methods
We sought to determine if a durable bilayer implant composed of trabecular metal with autologous periosteum on top would be suitable to reconstitute large osteochondral defects. This design would allow for secure implant fixation, subsequent integration and remodeling. Adult sheep were randomly assigned to one of three groups (n = 8/group): 1. trabecular metal/periosteal graft (TMPG), 2. trabecular metal (TM), 3. empty defect (ED). Cartilage and bone healing were assessed macroscopically, biochemically (type II collagen, sulfated glycosaminoglycan (sGAG) and double-stranded DNA (dsDNA) content) and histologically.Objectives
Materials and Methods
We present the medium-term clinical results of a reverse total
shoulder arthroplasty with a trabecular metal glenoid base plate. We reviewed 125 consecutive primary reverse total shoulder arthroplasties
(RTSA) implanted in 124 patients for rotator cuff arthropathy. There
were 100 women and 24 men in the study group with a mean age of
76 years (58 to 89). The mean follow-up was 32 months (24 to 60).
No patient was lost to follow-up.Aim
Patients and Methods
During open orthopaedic surgery, joints may be exposed to air, potentially leading to cartilage drying and chondrocyte death, however, the long-term effects of joint drying The patellar groove of anaesthetised rats was exposed (sham-operated), or exposed and then subjected to laminar airflow (0.25m/s; 60 minutes) before wounds were sutured and animals recovered. Animals were monitored for up to eight weeks and then sacrificed. Cartilage and chondrocyte properties were studied by histology and confocal microscopy, respectively.Objectives
Methods
There are several reports clarifying successful results following
open reduction using Ludloff’s medial approach for congenital (CDH)
or developmental dislocation of the hip (DDH). This study aimed
to reveal the long-term post-operative course until the period of
hip-joint maturity after the conventional surgical treatments. A long-term follow-up beyond the age of hip-joint maturity was
performed for 115 hips in 103 patients who underwent open reduction
using Ludloff’s medial approach in our hospital. The mean age at
surgery was 8.5 months (2 to 26) and the mean follow-up was 20.3
years (15 to 28). The radiological condition at full growth of the hip
joint was evaluated by Severin’s classification.Objectives
Methods
Intra-articular punctures and injections are performed routinely on patients with injuries to and chronic diseases of joints, to release an effusion or haemarthrosis, or to inject drugs. The purpose of this study was to investigate the accuracy of placement of the needle during this procedure. A total of 76 cadaver acromioclavicular joints were injected with a solution containing methyl blue and subsequently dissected to distinguish intra- from peri-articular injection. In order to assess the importance of experience in achieving accurate placement, half of the injections were performed by an inexperienced resident and half by a skilled specialist. The specialist injected a further 20 cadaver acromioclavicular joints with the aid of an image intensifier. The overall frequency of peri-articular injection was much higher than expected at 43% (33 of 76) overall, with 42% (16 of 38) by the specialist and 45% (17 of 38) by the resident. The specialist entered the joint in all 20 cases when using the image intensifier. Correct positioning of the needle in the joint should be facilitated by fluoroscopy, thereby guaranteeing an intra-articular injection.
We present a series of four patients with what we have termed the snapping pes syndrome. This is a painful clicking and catching experienced at the posteromedial corner of the knee when moving from flexion to extension. Clinical examination and real time ultrasound are the most useful diagnostic tools. If medical treatment is unsuccessful surgical excision of both the semitendinous and gracilis tendons is indicated for relief of persistent symptoms.
We examined 204 children (137 boys and 67 girls) aged 12 years and under with septic arthritis. Their mean age was 31.1 months (1 to 144; SD 41.6). The most common joints affected were the knees and shoulders.
We evaluated the use of surgical stabilisation for atlantoaxial subluxation after a follow-up of 24 years in 50 rheumatoid patients who had some degree of pain but no major neurological deficit. The mortality of patients treated by atlantoaxial fusion was significantly lower than for those who received conservative treatment. The deaths resulted from infection or comorbid conditions. The significantly high relative risks of mortality from conservative treatment compared with surgical treatment were mutilating disease and susceptible factors on both of the HLA-DRB1 alleles. Relief from pain and neurological and functional recovery were better, and the radiological degree of atlantoaxial translocation was less in those who were surgically treated compared with those who were not. Two patients had superficial local infections after surgery. We conclude that prophylactic atlantoaxial fusion is better than conservative treatment in these patients.
We analysed synovial fluid from 88 hips, 38 with osteoarthritis and 12 with well-functioning and 38 with loose hip prostheses. The levels of TNF-α, IL-1ß (71 hips) and IL-6 (45 hips) were measured using the ELISA technique.
We have used an experimental model employing the bent tail of rats to investigate the effects of mechanical forces on bones and joints. Mechanical strain could be applied to the bones and joints of the tail without direct surgical exposure or the application of pins and wires. The intervertebral disc showed stretched annular lamellae on the convex side, while the annulus fibrosus on the concave side was pinched between the inner corners of the vertebral epiphysis. In young rats with an active growth plate, a transverse fissure appeared at the level of the hypertrophic cell layer or the primary metaphyseal trabecular zone. Metaphyseal and epiphyseal trabeculae on the compressed side were thicker and more dense than those of the distracted part of the vertebra. In growing animals, morphometric analysis of hemiepiphyseal and hemimetaphyseal areas, and the corresponding trabecular bone density, showed significant differences between the compressed and distracted sides. No differences were observed in adult rats. We found no significant differences in osteoclast number between compressed and distracted sides in either age group. Our results provide quantitative evidence of the working of ‘Wolff’s law’. The differences in trabecular density are examples of remodelling by osteoclasts and osteoblasts; our finding of no significant difference in osteoclast numbers between the hemiepiphyses in the experimental and control groups suggests that the response of living bone to altered strain is mediated by osteoblasts.
One hundred normal fingers were dissected and arthrographs obtained by injection of a chromopaquegelatin mixture, allowing comparison between the radiographic and macroscopic configuration of the synovial capsule. Synovial recesses protruding from each side of every metacarpo-phalangeal joint were found in relation to the collateral ligaments and corresponding exactly with the site of radiological erosions. A group of bursae lying on the superficial aspect of collateral ligaments were also demonstrated. A rudimentary infra-articular meniscus was found. The results of examination of the insertions of the interossei showed differences from traditional descriptions. The cause of rheumatoid deformity was suggested to be the rheumatoid process arising in the lateral recesses and lateral bursae, weakening the collateral ligaments, which give way in the directions of the deforming forces. These are derived from the long flexor tendons, which were shown to exert an ulnar and volar strain on the metacarpo-phalangeal joint of every finger during grip.
Link arthroplasty is a system of joint replacement in which the joint is left almost intact with no great removal of bone. It is based on a two-piece self-locking hinge slotted into the metacarpal head and phalangeal shaft. The operation is simple and no special instruments are needed. The preliminary follow-up of fifty-four metacarpo-phalangeal joint replacements showed thirty-five good and sixteen fair results.
1. Two cases of locking of the metacarpo-phalangeal joint of the index finger are presented. 2. A simple classification of metacarpo-phalangeal joint locking is suggested, and the clinical features of the two main groups—degenerative and spontaneous—are described. 3. A routine approach to the treatment of the condition is suggested.
1. Twenty-two feet injured at the tarso-metatarsal level are reviewed. 2. Experiments with eleven cadaveric feet are reported. 3. The injuries are caused by forced plantar-flexion combined with rotation in most cases. Crushing of the foot alone often does not produce dislocation. 4. A classification is suggested. 5. The results of various treatments in this small series are presented. It is concluded that anatomical reduction is important, achieved if necessary by operation and internal fixation.
1. Four joints of three young haemophiliacs who died in traffic accidents have been examined. 2. All patients had received prompt specific treatment for intra-articular and other haemorrhages. 3. Major macroscopic and histological changes were seen in the joints, but these changes were not quite so severe as those described before the days of specific treatment. 4. The possibilities of preventing articular changes and of minimising the effect of blood in the joints are discussed.
Joint allotransplantation has a place in the treatment of joints destroyed by operation or disease. It is hoped that the results will improve with increasing knowledge of immunological mechanisms and with improvements in methods of internal fixation.
1. This paper describes the macroscopic and microscopic changes that are seen in posterior intervertebral joints after anterior vertebral fusion. 2. We now have a reasonably clear view of the types of change seen under these circumstances. The type varies from case to case and in different parts of the same specimen. So far we have no clear idea of the sequence or the pattern that leads from the normal to complete fibrosis or osseous ankylosis. 3. Further experimental work is needed in order to build up a clear concept of the sequence of events and of their relative importance. To do this it will be necessary to immobilise joints for longer than before.
1. A method of finger dissection is described which provides a new approach to the anatomical study of structures in close relation to joints. 2. The volar part of the capsule of the finger joints is described, the attachment to the bones being particularly emphasised together with its form which is like that of a meniscus. 3. A gap between bone and tendon sheath is described. 4. Theoretical and clinical aspects of the local anatomy are discussed.
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. Five cases of locked metacarpo-phalangeal joint are described. 2. The anatomy of this joint is described and its bearing on the mechanism of locking discussed. 3. A method of treatment is suggested.
1. Previous reports of calcareous deposits about the metacarpo-phalangeal joints are reviewed, and four further cases are described. 2. The clinical features are described, with reference to the possibility of erroneous diagnosis. 3. Conservative treatment is recommended.
Two cases of neuropathic joints in diabetes mellitus are described. The condition, though rare, must be kept in mind in diabetes with neuropathy. With proper control of the diabetes and supportive measures to the joints the prognosis is relatively good.
1. By reducing the viscosity of the synovial fluid within the ankle joints of rabbits and then subjecting these to prolonged exercise, wear and tear of articular cartilage can be consistently produced. 2. This finding is an indirect confirmation of the view that fluid film lubrication is an important factor in the mechanical efficiency of joints. 3. The special properties of synovial fluid and articular cartilage that allow fluid film lubrication to exist within joints that are, in effect, slowly moving, heavily loaded, reciprocating bearings are discussed. They account for the remarkable resistance to wear and tear exhibited by synovial joints under physiological conditions.
Streptomycin and iso-nicotinic acid hydrazide are two powerful drugs lethal to tubercle bacilli, when access to the infected tissues is free. For early disease, before ischaemia and necrosis become established, they are curative: afterwards they are not. In this paper the use of surgery to augment their action has been discussed. The development of such methods may well revolutionise the treatment of skeletal tuberculosis. Therein lies a danger because attempts to cure the patient by exterminating the tubercle bacilli in his lesion may lead to a precarious recovery: treatment directed against the bacilli may greatly facilitate a real cure if constitutional treatment is also applied to make the patient immune. Revolutionary though the change may become, it will not be so great as the revolution which occurred thirty years ago when open-air hospitals were first provided for patients with skeletal tuberculosis. The first patient ever seen on a surgical ward by the author, when he was a student, suffices still as an example. A child with tuberculosis of the cervical spine was admitted from out-patients with multiple discharging sinuses from the neck which was supported in a sodden plaster jacket. "Whoever," said the house surgeon dramatically, "removes that plaster, will kill that child." Most unfortunately his words were true. Many other such patients could, in those days, be seen in the wards of city hospitals. It was largely due to the work of Sir Robert Jones, friend of children, that the value of constitutional treatment became recognised. With the combination of the old knowledge and the development of the new, a new chapter in the treatment of skeletal tuberculosis has opened and rapid restoration of function and permanent cure can now take the place of long and sometimes crippling illness.
1. Experience in the treatment of tuberculous disease of the spine, hip and knee by combined constitutional, antibiotic and operative measures is described. 2. In patients with tuberculosis of the spine, especially in the thoracic region and when perispinal abscess formation is a prominent feature, the treatment helps to ensure stable ankylosis in the type of case in which it otherwise might not occur. 3. In children with tuberculosis of the hip and in adults and children with tuberculosis of the knee it is usually possible to save the joint and to restore function, provided the joint has not been destroyed before treatment is begun.
1. The dynamics of synovial joints depends upon the geometry of the articular surfaces, which are always curved. 2. There are two types of articular curvature: ovoid (synclastic) and sellar (anticlastic). 3. The sellar type is mechanically more suited to movements in which sliding is combined with medial or lateral rotation (monodal conjunct rotation). 4. The movement of any hinge-joint is accompanied by a monodal conjunct rotation. This carries the moving part along a path that approximates (at least) to a path of minimal wear. The same is true of the paths of habitual effort-movement (ergodes) of other kinds of joint. 5. Evidence for the foregoing statements is drawn from both normal and abnormal joints, and a clinical application is suggested.
1. All articulating cartilages are fibrocartilages. 2. The articular cartilages of the synovial joints are largely composed of collagen fibres. 3. These fibres form a dense network, the fibres of which run obliquely between the articular surface and the bone. 4. This network is operative when the parts are at rest and in contact under pressure. It takes the tensile component of the resultant shear stress, and is a postural mechanism of the joint. 5. The articular cartilage is most heavily chondrified at its centre, between the juxta-synovial and juxta-osseous parts. 6. The technique for demonstrating the fibrous structure is described.
1. Two cases of osteochondritis dissecans affecting several joints are described. 2. There is no evidence that injury, congenital anomaly or constitutional disturbance played any part in the etiology of either case.
1. Synovial fluid acts mechanically by forming a convergent lubricant film between the fixed and the moving joint surfaces. This term and the underlying theory are explained. 2. The fatty pads assist lubrication by reducing the "mechanical curvature" in joints with more highly curved surfaces. 3. The intra-articular discs and menisci increase the "mechanical curvature" in joints with surfaces of small curvature. 4. Sesamoid bones exert a "bow-string pressure" upon the bones with which they articulate. This is a corollary from the theory of lubrication.
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.
1. Muscles acting upon any joint can be divided into two principal groups: muscles of displacement or spurt muscles, and muscles of stabilisation or shunt muscles. 2. Muscles which arise far from the joint are spurt muscles; those which arise near it are shunt muscles. 3. The fibrous tendon sheaths are joint-stabiising mechanisms. 4. The lumbrical and interosseous muscles are muscles of stabilisation of the digits. 5. The arrangement of the musculature is such as to ensure a constant pressure across the joint cavity during rest or uniform movement. The necessary centripetal force during movement is supplied mainly by the shunt muscles. 6. Experiments are described to illustrate these observations.
1. Arthroplasty of the knee joint should be performed only in carefully selected cases. Criteria for the operation are outlined. 2. In our experience, 70 per cent. of properly selected patients secure good or fair results. An additional 12 per cent., whose anatomical or functional results were classified as poor, preferred the movement which had been gained to ankylosis of the joint. 3. The major functional adaptation of the knee joint takes place during the first five years after arthroplasty. Several patients who had a poor range of movement after one or two years developed an excellent range by the end of five years. 4. Instability, when present, usually became apparent within the first five years. 5.
1. Two successive movements at a joint, if not in one and the same plane, constitute a diadochal movement. 2. Diadochal movements impose conjunct rotation upon the bone which has been moved. This may be countered by a rotation of opposite sense. 3. All muscles of a given joint are, therefore, rotators in some degree. 4. Upon the basis of these principles diagnostic and therapeutic suggestions are made.