Advancing national climate change risk assessment to deliver national adaptation plans.

A wide range of climate vulnerability and risk assessments have been implemented using different approaches at different scales, some with a broad multi-sectoral scope and others focused on single risks or sectors. This paper describes the novel approach to vulnerability and risk assessment which was designed and put into practice in the United Kingdom's Second Climate Change Risk Assessment (CCRA2) so as to build upon its earlier assessment (CCRA1). First, we summarize and critique the CCRA1 approach, and second describe the steps taken in the CCRA2 approach in detail, providing examples of how each was applied in practice. Novel elements of the approach include assessment of both present day and future vulnerability, a focus on the urgency of adaptation action, and a structure focused around systems of receptors rather than conventional sectors. Both stakeholders and reviewers generally regarded the approach as successful in providing advice on current risks and future opportunities to the UK from climate change, and the fulfilment of statutory duty. The need for a well-supported and open suite of impact indicators going forward is highlighted.This article is part of the theme issue 'Advances in risk assessment for climate change adaptation policy'.

Altered regional loading patterns on articular cartilage following meniscectomy are not fully restored by autograft meniscal transplantation.

OBJECTIVE: To quantify the changes in regional dynamic loading patterns on tibial articular cartilage during simulated walking following medial meniscectomy and meniscal transplantation. METHODS: Seven fresh frozen human cadaveric knees were tested under multidirectional loads mimicking the activity of walking, while the contact stresses on the tibial plateau were synchronously recorded using an electronic sensor. Each knee was tested for three conditions: intact meniscus, medial meniscectomy, and meniscal transplantation. The loading profiles at different locations were assessed and common loading patterns were identified at different sites of the tibial plateau using an established numerical algorithm. RESULTS: Three regional patterns were found on the tibial plateau of intact knees. Following medial meniscectomy, the area of the first pattern which was located at the posterior aspect of the medial plateau was significantly reduced, while the magnitude of peak load was significantly increased by 120%. The second pattern which was located at the central-posterior aspects of the lateral plateau shifted anteriorly and laterally without changing its magnitude. The third pattern in the cartilage-to-cartilage contact region of the medial plateau was absent following meniscectomy. Meniscal transplantation largely restored the first pattern, but it did not restore the other two patterns. CONCLUSION: There are site-dependent changes in regional loading patterns on both the medial and lateral tibial plateau following medial meniscectomy. Even when a meniscal autograft is used where the geometry and material properties are kept constant, the only region in which the loading pattern is restored is at posterior aspect of the medial plateau.

Atmospheric lifetimes of long-lived halogenated species.

The atmospheric lifetimes of the fluorinated gases CF(4), C(2)F(6), c-C(4)F(8), (CF(3))(2)c-C(4)F(6), C(5)F(12), C(6)F(14), C(2)F(5)Cl, C(2)F(4)C(12), CF(3)Cl, and SF(6) are of concern because of the effects that these long-lived compounds acting as greenhouse gases can have on global climate. The possible atmospheric loss processes of these gases were assessed by determining the rate coefficients for the reactions of these gases with O((1)D), H, and OH and the absorption cross sections at 121.6 nanometers in the laboratory and using these data as input to a two-dimensional atmospheric model. The lifetimes of all the studied perfluoro compounds are >2000 years, and those of CF(3)Cl, CF(3)CF(2)Cl, and CF(2)ClCF(2)Cl are >300 years. If released into the atmosphere, these molecules will accumulate and their effects will persist for centuries or millennia.

Increased utilization of constraint in total knee arthroplasty following anterior cruciate ligament and multiligament knee reconstruction.

AIMS: Anterior cruciate ligament (ACL) and multiligament knee (MLK) injuries increase the risk of development of knee osteoarthritis and eventual need for total knee arthroplasty (TKA). There are limited data regarding implant use and outcomes in these patients. The aim of this study was to compare the use of constrained implants and outcomes among patients undergoing TKA with a history of prior knee ligament reconstruction (PKLR) versus a matched cohort of patients undergoing TKA with no history of PKLR. PATIENTS AND METHODS: Patients with a history of ACL or MLK reconstruction who underwent TKA between 2007 and 2017 were identified in a single-institution registry. There were 223 patients who met inclusion criteria (188 ACL reconstruction patients, 35 MLK reconstruction patients). A matched cohort, also of 223 patients, was identified based on patient age, body mass index (BMI), sex, and year of surgery. There were 144 male patients and 79 female patients in both cohorts. Mean age at the time of TKA was 57.2 years (31 to 88). Mean BMI was 29.7 kg/m2 (19.5 to 55.7). RESULTS: There was a significantly higher use of constrained implants among patients with PKLR (76 of 223, 34.1%) compared with the control group (40 of 223, 17.9%; p < 0.001). Subgroup analysis showed a higher use of constrained implants among patients with prior MLK reconstruction (21 of 35, 60.0%) compared with ACL reconstruction (55 of 188, 29.3%; p < 0.001). Removal of hardware was performed in 69.5% of patients with PKLR. Mean operative time (p < 0.001) and tourniquet time (p < 0.001) were longer in patients with PKLR compared with controls. There were no significant differences in rates of deep vein thrombosis, pulmonary embolism, infection, transfusion, postoperative knee range of movement (ROM), or need for revision surgery. There was no significant difference in preoperative or postoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR) scores between groups. CONCLUSION: Results of this study suggest a history of PKLR results in increased use of constrained implants but no difference in postoperative knee ROM, patient-reported outcomes, or incidence of revision surgery. Cite this article: Bone Joint J 2019;101-B(7 Supple C):77-83.

Effect of pre-operative expectations on the outcomes following total shoulder arthroplasty.

AIMS: Few studies have evaluated the relationship between patients' pre-operative expectations and the outcome of orthopaedic procedures. Our aim was to determine the effect of expectations on the outcome after primary anatomical total shoulder arthroplasty (TSA). We hypothesised that patients with greater expectations would have better outcomes. PATIENTS AND METHODS: Patients undergoing primary anatomical TSA completed the Hospital for Special Surgery's Shoulder Expectations Survey pre-operatively. The American Shoulder and Elbow Surgeons (ASES), Shoulder Activity Scale (SAS), Short-Form-36 (SF-36), and visual analogue scale (VAS) for pain, fatigue, and general health scores were also collected pre-operatively and two years post-operatively. Pearson correlations were used to assess the relationship between the number of expectations and the outcomes. Differences in outcomes between those with higher and lower levels of expectations for each expectation were assessed by independent samples t-test. Multivariable linear regression analysis was used to control for potential confounding factors. RESULTS: A total of 67 patients were evaluated two years post-operatively. Most parameters of outcome improved significantly from baseline and most patients were satisfied. A greater number of expectations was associated with a significantly greater improvement in the ASES score (p = 0.02). In the multivariable analysis, a greater number of expectations was an independent predictor of better ASES, VAS and SF-36 scores, as well as improvements in ASES and VAS pain scores (p < 0.05). Greater expectations for many specific expectation questions were significantly associated with better outcomes (p < 0.05). CONCLUSION: TSA is a successful procedure with significant improvements in outcome, and greater pre-operative expectations are associated with better outcomes. Cite this article: Bone Joint J 2017;99-B:1190-6.

Preoperative planning for accurate glenoid component positioning in reverse shoulder arthroplasty.

BACKGROUND: Glenoid component positioning in reverse shoulder arthroplasty (RSA) is challenging. Patient-specific instrumentation (PSI) has been advocated to improve accuracy, and is based on precise preoperative planning. The purpose of this study was to determine the accuracy of glenoid component positioning when only the glenoid surface is visible, compared to when the entire scapula is visible on a 3D virtual model. METHODS: CT scans of 30 arthritic shoulders were reconstructed in 3D models. Two surgeons then virtually placed a glenosphere component in the model while visualizing only the glenoid surface, in order to simulate typical intraoperative exposure ("blind 3D" surgery). One surgeon then placed the component in an ideal position while visualizing the entire scapula ("visible 3D" surgery). These two positions were then compared, and the accuracy of glenoid component positioning was assessed in terms of correction of native glenoid version and tilt, and avoidance of glenoid vault perforation. RESULTS: Mean version and tilt after "blind 3D" surgery were +1.4° (SD 8.8°) and +7.6° (SD 6°), respectively; glenoid vault perforation occurred in 17 specimens. Mean version and tilt after "visible 3D" surgery were +0.3° (SD 0.8°) and +0.1° (SD 0.5°), respectively, with glenoid vault perforation in 6 cases. "Visible 3D" surgery provided significantly better accuracy than "blind 3D" surgery (P<0.05). CONCLUSION: When the entire scapula is used as reference, accuracy is improved and glenoid vault perforation is less frequent. This type of visualization is only possible with pre-operative 3D CT planning, and may be augmented by PSI. LEVEL OF EVIDENCE: Basic science study. Level III.

Changes in the chondroitin sulfate-rich region of articular cartilage proteoglycans in experimental osteoarthritis.

The chondroitin sulfate-rich region was cleaved from cartilage proteoglycans of experimental osteoarthritic canine joints to establish whether changes in this region of the molecule contribute to the well-documented increase in the chondroitin sulfate to keratan sulfate ratio in osteoarthritis. Experimental osteoarthritis was induced in eight dogs by severance of the right anterior cruciate ligament, the left joint serving as a control. Proteoglycans were extracted from the femoral cartilage of both joints, isolated as A1 fractions by associative density gradient centrifugation and cleaved with hydroxylamine. The chondroitin sulfate-rich region was isolated by either gel chromatography or dissociative density gradient centrifugation. The chondroitin sulfate-rich region from the proteoglycans of the experimental osteoarthritic joints was slightly larger in hydrodynamic size and had both a higher uronate/protein weight ratio and galactosamine/glucosamine molar ratio than the corresponding control. We conclude that the chondroitin sulfate-rich region of proteoglycans in articular cartilage of experimental osteoarthritic joints is larger and has more chondroitin sulfate than that of proteoglycans of normal cartilage.

A new Ac-like transposon of Arabidopsis is associated with a deletion of the RPS5 disease resistance gene.

The RPS5 and RFL1 disease resistance genes of Arabidopsis ecotype Col-0 are oriented in tandem and are separated by 1.4 kb. The Ler-0 ecotype contains RFL1, but lacks RPS5. Sequence analysis of the RPS5 deletion region in Ler-0 revealed the presence of an Ac-like transposable element, which we have designated Tag2. Southern hybridization analysis of six Arabidopsis ecotypes revealed 4-11 Tag2-homologous sequences in each, indicating that this element is ubiquitous in Arabidopsis and has been active in recent evolutionary time. The Tag2 insertion adjacent to RFL1 was unique to the Ler-0 ecotype, however, and was not present in two other ecotypes that lack RPS5. DNA sequence from the latter ecotypes lacked a transposon footprint, suggesting that insertion of Tag2 occurred after the initial deletion of RPS5. The deletion breakpoint contained a 192-bp insertion that displayed hallmarks of a nonhomologous DNA end-joining event. We conclude that loss of RPS5 was caused by a double-strand break and subsequent repair, and cannot be attributed to unequal crossing over between resistance gene homologs.

Identification of three putative signal transduction genes involved in R gene-specified disease resistance in Arabidopsis.

The RPS5 disease resistance gene of Arabidopsis mediates recognition of Pseudomonas syringae strains that possess the avirulence gene avrPphB. By screening for loss of RPS5-specified resistance, we identified five pbs (avrPphB susceptible) mutants that represent three different genes. Mutations in PBS1 completely blocked RPS5-mediated resistance, but had little to no effect on resistance specified by other disease resistance genes, suggesting that PBS1 facilitates recognition of the avrPphB protein. The pbs2 mutation dramatically reduced resistance mediated by the RPS5 and RPM1 resistance genes, but had no detectable effect on resistance mediated by RPS4 and had an intermediate effect on RPS2-mediated resistance. The pbs2 mutation also had varying effects on resistance mediated by seven different RPP (recognition of Peronospora parasitica) genes. These data indicate that the PBS2 protein functions in a pathway that is important only to a subset of disease-resistance genes. The pbs3 mutation partially suppressed all four P. syringae-resistance genes (RPS5, RPM1, RPS2, and RPS4), and it had weak-to-intermediate effects on the RPP genes. In addition, the pbs3 mutant allowed higher bacterial growth in response to a virulent strain of P. syringae, indicating that the PBS3 gene product functions in a pathway involved in restricting the spread of both virulent and avirulent pathogens. The pbs mutations are recessive and have been mapped to chromosomes I (pbs2) and V (pbs1 and pbs3).

In vivo healing after capsular plication in an ovine shoulder model.

Traditionally, arthroscopic management of shoulder instability has been reserved for patients with isolated Bankart lesions without any capsular laxity or injury. To date, there are no animal studies evaluating the healing potential of capsular plication and/or capsulo-labral repair. The purpose of this in vivo animal study was to determine if the histological capsular healing of an open capsular plication simulating an arthroscopic plication is equivalent to the more traditional open capsular shift involving cutting and advancing the capsule. Twenty-six skeletally mature sheep were randomized to either an open capsular plication simulating arthroscopic plication (n = 13), or an open traditional capsular shift (n = 13). A sham operation (n = 4) was also performed involving exposure to visualize the capsule. Normal non-operated control shoulders were also analyzed. A pathologist blinded to the treatment evaluated both hematoxylin and eosin (H&E) sections and polarized light microscopy. Qualitative scoring evaluated fibrosis, mucinous degeneration, fat necrosis, granuloma formation, vascularity, inflammatory infiltrate and hemosiderin (0 to 3 points). Both the capsular plication and open shift groups demonstrated healing by fibrosis at the site of surgical manipulation. There were no statistical differences in the capsular healing responses between the two groups with regard to fibrosis, granuloma formation and vascularity. The open shift group demonstrated significantly more mucinous degeneration (p = 0.038). Fat necrosis was present in 4/13 specimens in the open shift group and none in the capsular plication specimens. Both groups demonstrated disorganized collagen formation under polarized light microscopy. There were no differences between non-operated control specimens and sham surgery specimens. Our findings support the hypothesis that histologic capsular healing is equivalent between the plication group and the open shift group. In addition, the open shift group demonstrated significantly more changes indicative of tissue injury. This basic science model confirms capsular healing after simulated arthroscopic plication, providing support for arthroscopic capsular plication in practice.

Overexpression of Pti5 in tomato potentiates pathogen-induced defense gene expression and enhances disease resistance to Pseudomonas syringae pv. tomato.

The tomato Pti5 gene encodes a pathogen-inducible ethylene response element-binding protein-like transcription factor that interacts with the disease resistance gene product Pto. Overexpression of Pti5 or Pti5-VP16, a translational fusion with a constitutive transcriptional activation domain, in tomato enhanced resistance to Pseudomonas syringae pv. tomato. Constitutive expression of Pti5 or Pti5-VP16 did not affect the basal level of pathogenesis-related gene expression, but it accelerated pathogen-induced expression of GluB and Catalase. The results demonstrate a positive role of Pti5 in defense gene regulation and disease resistance and suggest that a pathogen-activated posttranscriptional regulatory step is necessary for the pathogen induction of the defense gene expression.

Enhanced matrix synthesis and in vitro formation of cartilage-like tissue by genetically modified chondrocytes expressing BMP-7.

Bone morphogenic protein-7 (BMP-7) supports ectopic cartilage and bone formation, is expressed in normal articular cartilage, and increases matrix synthesis in chondrocytes. Based on this knowledge, we hypothesized that an adenovirus (Ad) vector encoding human BMP-7 could be used to modify chondrocytes genetically to improve their capacity for cartilage repair. An adenovirus vector encoding BMP-7 (AdBMP-7) was constructed and its bioactivity confirmed by ectopic bone formation assay. AdBMP-7 modification of bovine chondrocytes induced expression of BMP-7 mRNA and bioactive protein, resulting in an increase in incorporation of 35SO4- into proteoglycan, 3H-proline uptake into protein, and the expression of the cartilage-specific matrix genes, aggrecan and type II collagen. An in vitro model of chondrocyte transplantation was used to demonstrate the feasibility of using genetically modified chondrocytes to enhance formation of cartilage-like tissue. When transplanted onto cartilage explants and maintained in vitro for 3 weeks, chondrocytes modified with AdBMP-7 formed 1.9-fold thicker tissue than chondrocytes modified with a control vector (P < 0.001). This tissue was positive for type II collagen and proteoglycan but negative for type X collagen and demonstrated a cartilage-like morphology. These observations suggest that Ad-mediated transfer of BMP-7 gene to chondrocytes enhances the chondrocyte-specific matrix synthesis and their capacity to form cartilage-like tissue, thus representing a strategy that may improve cell-based cartilage repair.

The effect of cryopreservation on canine menisci: a biochemical, morphologic, and biomechanical evaluation.

This study evaluated the effect of cryopreservation on the structural organization, biosynthetic activity, and material properties of canine menisci. The menisci were cryopreserved by incubating them in a 4% solution of dimethyl sulfoxide (DMSO) in physiologic media and freezing them to -100 degrees C using a controlled rate freezing system. The menisci were then stored for varying periods of time from zero to 12 weeks in liquid nitrogen (-196 degrees C). Following rapid thawing, changes in the histological appearance and biosynthetic activity of the menisci were evaluated as functions of storage time. In addition, the effects of the cryopreservation process on the tensile strength and modulus of the meniscal tissue were assessed. Although cryopreservation and short-term storage did not appear to affect the morphological appearance or biomechanical character of the menisci, biosynthetic activity, as determined by Na2S35SO4 incorporation, was diminished to less than 50% of normal control values immediately following cryopreservation and thawing. Autoradiographic examination of these tissues revealed that only approximately 10% of the meniscal cells were metabolically active, however, indicating that a marked increase in the metabolic activity of individual cells occurs following the freeze-thaw cycle. Total metabolic activity continued to decline with storage time.

Measurement reproducibility of two commercial knee test devices.

Objective evaluation of patients' knee motion using mechanical devices, whether for diagnostic purposes or for assessing rehabilitative procedures, requires that these devices be reproducible, in order to avoid errors independent of the patients' condition. This study prospectively evaluates the reproducibility of two commercial knee test systems, the KT 1000 Knee Ligament Arthrometer and the Genucom Knee Analysis System, by performing repeated measurements on twenty normal men. Average knee motion, between-subject variance, and within-subject variance were determined by performing repeat tests on the same day and one week later. No significant difference was found between measurements taken on the two different test days, but the within-subject variation was high. We found that larger applied forces or moments resulted in a larger variation in mean displacements. However, the percent variation about the mean (coefficient of variation) decreased with increasing applied loads. The coefficient of variation for the KT 1000 varied from 8 to 33% and for the Genucom, from 13 to 87%. On an individual basis, large variations were found in repeated measures for both devices. To minimize errors, we recommend that repeated tests be performed, higher forces and moments utilized, and specific flexion angles be used for each device and test. Even under these conditions, caution must be exercised when evaluating individual subjects.

Immunolocalization of cytokines and their receptors in adhesive capsulitis of the shoulder.

The purpose of this study was to test the hypothesis that specific cytokines are involved in the initiation and evolution of the fibrotic process in adhesive capsulitis of the shoulder. After approval from the Institutional Review Board, biopsies of shoulder capsule and synovium were collected during shoulder arthroscopy from 19 patients with adhesive capsulitis, 14 patients with nonspecific synovitis and no fibrosis or clinical evidence of adhesive capsulitis, and seven patients undergoing surgery for another pathology who had a normal capsule and synovium. Immunohistochemical localization with monoclonal antibodies to transforming growth factor-beta and its receptor, platelet-derived growth factor and its receptor, basic fibroblast growth factor, interleukin-1 beta, tumor necrosis factor-alpha, and hepatocyte growth factor was performed using standard immunoperoxidase techniques. The frequency of cytokine staining was correlated with the clinical diagnosis. Synovial cells, fibroblasts, T-cells, and B-cells were identified with specific antibodies, and newly synthesized matrix was examined for type-I and type-III collagen by immunohistochemical staining. The predominant cell types present were synovial cells and fibroblasts. Staining for type-III collagen in adhesive capsulitis tissues indicated new deposition of collagen in the capsule. There was staining for transforming growth factor-beta and its receptor, platelet-derived growth factor and its receptor, interleukin-1 beta, and tumor necrosis factor-alpha in adhesive capsulitis and nonspecific synovitis tissues, compared with minimal staining in normal capsule. Staining was more frequent in synovial cells than in capsular cells. The frequency of cell and matrix staining for transforming growth factor-beta, platelet-derived growth factor, and hepatocyte growth factor was greater in adhesive capsulitis tissues than in those from patients with nonspecific synovitis. No difference in the frequency of staining between primary (idiopathic) and secondary adhesive capsulitis was found. The results of this study indicate that adhesive capsulitis involves both synovial hyperplasia and capsular fibrosis. Cytokines such as transforming growth factor-beta and platelet-derived growth factor may be involved in the inflammatory and fibrotic processes in adhesive capsulitis. Matrix-bound transforming growth factor-beta may act as a persistent stimulus, resulting in capsular fibrosis. Understanding the basic pathophysiology of adhesive capsulitis is an important step in the development of clinically useful antifibrotic agents that may serve as novel treatments for patients with this conditions.

Characterization of chemotactic migration and growth kinetics of canine knee ligament fibroblasts.

Migration and proliferation of ligament fibroblasts are essential for the healing of ligament injuries. This study was designed to evaluate the migration of intraarticular (anterior and posterior cruciate) and extraarticular (medial and lateral collateral) ligament fibroblasts in response to cytokines and to determine the effect of cell passage on cell proliferation. Recombinant human platelet-derived growth factor, hepatocyte growth factor/scatter factor, and bone morphogenic protein-2 stimulated the migration of all ligament cells in a dose-dependent manner, with optimal migration at 10 ng/ml. Recombinant human epithelial growth factor preferentially stimulated the migration of intraarticular ligament fibroblasts, whereas recombinant human interleukin-1 was more effective with extraarticular ligament fibroblasts. Recombinant human insulin-like growth factor-1, insulin-like growth factor-2, transforming growth factor-beta, and fibroblast growth factor had no significant effect on the migration of ligament-derived fibroblasts. These data suggest that specific cytokines stimulate the migration of knee ligament fibroblasts and provide a rationale for possible therapeutic approaches to optimize ligament healing. Fibroblasts derived from the anterior cruciate ligament have been shown to proliferate at a slower rate than those derived from the medial collateral ligament. We have extended these observations and have demonstrated that fibroblasts from both the posterior and anterior cruciate ligaments proliferate at a slower rate than lateral and medial collateral ligament-derived fibroblasts. The differences between the growth rates of intraarticular and extraarticular fibroblasts become insignificant with serial passaging of the cells.

Differential expression of integrin subunits in canine knee ligament fibroblasts.

A method for measuring the expression of integrin subunits on the cell surface of knee ligament fibroblasts was developed with use of flow cytometry and immunofluorescence. The ligament cells exhibited uniform size and density, as shown by forward and side-scatter properties, and showed minimal nonspecific binding of isotype control antibodies compared with unstained cells. All cells expressed the alpha5 integrin subunit; lateral collateral ligament cells stained with antibody to alpha5 showed a mean fluorescence intensity 2-fold higher than that of medial collateral ligament cells, 1.5-fold higher than that of posterior cruciate ligament cells, and 3-fold higher than that of anterior cruciate ligament cells, indicating a greater expression of the alpha5 subunit by lateral collateral ligament cells than by medial collateral, posterior cruciate, and anterior cruciate ligament cells. All cells expressed the beta1 integrin subunit; the expression by posterior cruciate ligament cells was 3-fold higher than that by medial collateral ligament or lateral collateral ligament cells and 5-fold higher than that by anterior cruciate ligament cells. All cells expressed the beta3 integrin subunit; the expression by posterior cruciate ligament cells was 1.5, 3, and 4.5-fold greater than that by lateral collateral, anterior cruciate, and medial collateral ligament cells, respectively. Our data suggest there is a differential expression of integrin subunits in knee ligament fibroblasts, and this in part may explain differences in their attachment and adherence to extracellular matrix molecules.

Knee injuries and Alpine skiing. Treatment and rehabilitation.

Alpine skiing is an increasingly popular recreational sport worldwide. While the overall injury rate has declined and the pattern of injury changed over the years, the incidence of knee injuries has not changed substantially and accounts for 20 to 30% of all alpine skiing injuries. Medial collateral ligament (MCL) injuries are the most common in skiing, accounting for 15 to 20% of all skiing injuries and 60% of knee injuries in skiers. Tears are commonly isolated, but may occur in association with other ligamentous injuries. Associated meniscal pathology is rare. Isolated MCL injuries are treated nonoperatively with a programme of initial immobilisation, early range-of-motion, and isometric quadriceps strengthening exercises. When full range of motion is achieved, a programme of progressive resistance exercises, isokinetic and closed chain exercises, and functional rehabilitation is instituted. Good results with return to skiing can be expected in most cases. Isolated lateral collateral ligament (LCL) injuries are rare in skiers. There is usually associated cruciate or arcuate ligament complex. Careful physical examination is essential to rule out associated ligament injuries and more complex instability patterns. In the rare case of isolated LCL injury, a similar approach to isolated MCL injury should be instituted. Anterior cruciate ligament (ACL) injuries have become increasingly common in skiers. This may reflect a true increase in the incidence or an improved awareness and ability to diagnose ACL injury. Physical examination and arthrometric analysis are important in assessing the integrity of the ACL. Radiographic and magnetic resonance imaging (MRI) evaluation may be helpful in assessing associated meniscal pathology. Treatment of the ACL-deficient knee is usually surgical. However, prior to reconstruction, a programme aimed at reducing effusion and regaining a full, pain-free range of motion is recommended. Surgical reconstruction is usually with the central third of the patella tendon using a bone-tendon-bone autograft. Postoperative rehabilitation employs a functional staged approach, requiring vigilant supervision by the surgeon. Isolated posterior cruciate ligament (PCL) injury is rare in skiing, constituting less than 1% of all knee injuries in most series. Careful physical examination must be employed to rule out associated arcuate ligament complex injury and more complex patterns of instability. Most isolated PCL injuries are treated nonoperatively with a programme of initial immobilisation in extension, ice, protected weight-bearing, early range-of-motion exercises and progressive isometric strengthening.(ABSTRACT TRUNCATED AT 400 WORDS)

Posterior subluxation of the glenohumeral joint.

Twenty-four patients who had posterior subluxation of the glenohumeral joint were assigned to one of two groups on the basis of the severity of the symptoms. The sixteen patients in Group I, who had less severe symptoms, were treated with a physical therapy program that was based on exercises to strengthen muscles. The eleven patients in Group II (three of whom had no success with physical therapy when they were originally in Group I) had a posterior capsulorrhaphy, with or without a bone block. According to an over-all rating, Group I had a rate of success of 63 per cent, and Group II had a rate of success of 91 per cent. The patients who had more severe ligamentous laxity were not more likely to fail either of the treatment programs. Although voluntary subluxation may be a subtle but important indicator of underlying emotional difficulties, it appears that, in the patient who is emotionally stable, the ability to voluntarily subluxate the shoulder posteriorly is not associated with a negative prognosis for either non-surgical or surgical treatment. Patients who have moderately disabling posterior subluxation of the shoulder should be treated with an intensive program that is designed to strengthen muscles. Patients who have symptoms that are severely disabling or who have had no success with non-operative treatment should be treated with posterior capsulorrhaphy. When the posterior aspect of the glenoid is severely deficient and when the posterior portion of the capsule or the infraspinatus tendon is attenuated, a bone block should augment the reconstruction.

T-plasty modification of the Bankart procedure for multidirectional instability of the anterior and inferior types.

Forty patients who had a diagnosis of multidirectional instability of forty-two shoulders had a modified Bankart operation in which a T-shaped incision was made in the anterior portion of the capsule, with advancement of the inferior flap superiorly and of the superior flap medially. All of the patients had been injured during athletic activities. Some degree of anterior labral injury was present in thirty-eight of the forty-two shoulders. Half of the patients had generalized ligamentous laxity. The patients were followed for an average of three years (range, two to seven years). Four patients had episodes of instability after the operation. Three had a single episode of posterior subluxation during throwing, one had recurrent posterior subluxation that subsequently was treated by posterior stabilization, and one had anterior subluxation while he was diving from a high board. The average loss of external rotation after the operation was 5 degrees with the arm at the side and 4 degrees with the arm abducted 90 degrees. Satisfaction of the patient was rated excellent for forty (95 per cent) of the shoulders, good for one shoulder, and fair for one shoulder. However, throwing athletes found that they were unable to throw a ball with as much speed as before the operation.