Crop production in the USA is frequently limited by a lack of pollinators

Most of the world's crops depend on pollinators, so declines in both managed and wild bees raise concerns about food security. However, the degree to which insect pollination is actually limiting current crop production is poorly understood, as is the role of wild species (as opposed to managed honeybees) in pollinating crops, particularly in intensive production areas. We established a nationwide study to assess the extent of pollinator limitation in seven crops at 131 locations situated across major crop-producing areas of the USA. We found that five out of seven crops showed evidence of pollinator limitation. Wild bees and honeybees provided comparable amounts of pollination for most crops, even in agriculturally intensive regions. We estimated the nationwide annual production value of wild pollinators to the seven crops we studied at over $1.5 billion; the value of wild bee pollination of all pollinator-dependent crops would be much greater. Our findings show that pollinator declines could translate directly into decreased yields or production for most of the crops studied, and that wild species contribute substantially to pollination of most study crops in major crop-producing regions.

Comparison of open and arthroscopic stabilization for recurrent shoulder dislocation in patients with a Bankart lesion

We performed a prospective study of 117 patients (119 shoulders) with symptomatic, recurrent anterior posttraumatic shoulder instability to compare open versus arthroscopic reconstruction. Arthroscopic reconstructions (N = 66) were performed using bioabsorbable tacks (Suretac fixators), whereas open reconstructions (N = 53) were performed with suture anchors. All of the patients had a Bankart lesion. Independent observers examined 108 of the 119 shoulders (91%) at a median follow-up period of 28 months (range, 24 to 63) for the arthroscopic group and 36 months (range, 24 to 63) for the open group. The recurrence rate, including both dislocations and subluxations, was 9 of 60 (15%) in the arthroscopic group, compared with 5 of 48 (10%) in the open group. At follow-up, the Rowe score was 93 points (range, 39 to 100) and the Constant score was 91 points (range, 56 to 100) in the arthroscopic group, compared with 89 points (range, 53 to 100 and 57 to 100 for the Rowe and Constant scores, respectively) for both scores in the open group. The only significant difference was in external rotation in abduction, which was 90 degrees (range, 50 degrees to 135 degrees) in the arthroscopic group and 80 degrees (range, 25 degrees to 115 degrees) in the open group. Both methods produced stable and well-functioning shoulders in the majority of patients.

Back pain and radiological changes in the thoraco-lumbar spine of athletes. A long-term follow-up

From 1996 to 1999, back pain and radiological changes in the thoraco-lumbar spine were investigated in 134 former top athletes, representing wrestling, gymnastics, soccer and tennis (age 27-39 years) and a group of 28 non-athletes of comparable age. This is a long-term follow-up investigation of a previous radiological study of the spine with clinical correlation. Despite significantly more radiological abnormalities among the athletes, they did not report higher frequency of back pain than the non-athletes. A decrease in disc height or new disc height reduction in one or more of the intervertebral discs between the two examinations correlated significantly with back pain at follow-up.

Exposure of the porcine spine to mechanical compression: differences in injury pattern between adolescents and adults

Recent studies of the spine in adolescents who have sustained trauma have shown injuries to the growth zone, whereas injuries to the vertebral body have been described in other studies of only adults. There are also reports on different clinical signs and radiological findings in adolescents with lumbar disc herniation when compared to adults. In order to find an explanation for these differences between adolescents and adults, this experimental study was performed. Six cadaveric lumbar motion segments (vertebral body-disc-vertebral body) obtained from three young male pigs and six lumbar motion segments obtained from three mature male pigs were tested in axial compression to failure. All units were examined with plain radiography and magnetic resonance imaging before and after compression. After the compression, histological samples were taken from the injury site. In the adolescents, a fracture was consistently found in the endplate through the posterior part of the growth zone, displacing the anulus fibrosus with a bony fragment at the point of insertion to the vertebra. This type of injury could not be detected in any of the adults; instead, there was a fracture of the vertebra in four cases, and in two cases, a rupture of the anulus fibrosus without a bony fragment was seen. This study showed that, when compressed to failure, the weakest part of the lumbar spine of the adolescent pig differs from that of the mature pig in the same way that studies on human spinal units have shown.

Early mobilization versus immobilization after ankle ligament stabilization

Functional outcome, stability at radiographic investigation and ankle joint torque after anatomical reconstruction of the lateral ankle ligaments were evaluated in patients with early postoperative mobilization versus those with cast immobilization. Thirty patients with chronic lateral ligament instability of the ankle underwent anatomical reconstruction of the ligaments. Postoperatively the patients were randomly allocated to two groups: Group A (n=15) were immobilized in a below-knee plaster for 6 weeks and Group B (n=15) underwent early controlled range of motion training using an Air-Cast ankle brace. The functional results were evaluated using a scoring scale and objective results using standardized stress radiographs. Also eccentric and concentric muscle torque at 60 degrees/s was measured in plantar flexion and dorsiflexion, respectively. The functional results were satisfactory in 12/15 ankles in Group A and 14/15 in Group B (n.s.). All the patients with satisfactory results regained normal range of motion. Patients with unsatisfactory results had either residual pain or recurrent instability. In Group B, the strength measurements revealed significantly higher peak torque values after three months in plantar flexion at 60 degrees/s. Six months postoperatively, the torque values did not differ significantly between the groups. Also, there was no group difference in the laxity of the ankle joint, including both anterior talar translation test and talar tilt test, at the two-year follow-up. One patient had a superficial wound infection. We conclude that after the reconstruction of chronic lateral ligament instability of the ankle the functional and stability results were equally good with early postoperative mobilization and 6-week immobilization. However, using early mobilization plantar flexion strength was regained earlier than with cast immobilization, without any risk of short- or medium-term complications, such as increased ankle laxity. We recommend early mobilization after anatomical reconstruction of the lateral ankle ligaments.

Comparison of arthroscopic one-incision and two-incision techniques for reconstruction of the anterior cruciate ligament

The purpose of this study was to assess the outcome of arthroscopic anterior cruciate ligament reconstruction performed using either the 'one-incision' technique or the rear-entry 'two-incision' technique. A series of 221 consecutive patients who underwent anterior cruciate ligament reconstruction was reviewed retrospectively. In the study population, two subgroups were defined. Group A consisted of 118 patients who underwent reconstruction using the one-incision transtibial endoscopic technique and Group B consisted of 103 patients who underwent reconstruction using the two-incision technique. The groups were comparable in terms of age, sex and activity level. The follow-up was performed after 47 (40-68) months in Group A and 55 (40-68) months in Group B. The Lysholm score at the final follow-up was significantly lower in Group A (90, 38-100) than in Group B (94, 34-100) (P = 0.002). The median KT-1000 total side-to-side difference was 1.5 (-6 to 7.5) mm in Group A, and 2.0 (-3.5 to 9) mm in Group B (n.s.). No significant difference between the groups was found when the IKDC evaluation system was used. Four intra-operative complications were registered in Group A and none in Group B (P = 0.06). No significant difference was found in terms of anterior knee pain, the one-leg-hop quotient or the activity level at the final follow-up. In this study the two methods gave similar and satisfactory results. Serious intraoperative complications were, however, recorded in four cases when the one-incision technique was used.

Reconstruction of the anterior cruciate ligament: comparison of outside-in and all-inside techniques

The aim of this prospective study was to compare two arthroscopic techniques for reconstructing the anterior cruciate ligament, the "outside-in" (two incisions) and the "all-inside" (one incision) techniques. The results obtained for 30 patients operated on using the "outside-in" technique (group I) were compared with those for 29 patients operated on using the "all-inside" technique (group II). Before surgery, there were no significant differences between the groups in terms of Lysholm score, Tegner activity level, patellofemoral pain score, or knee laxity. Both groups displayed significant improvements in Lysholm score after 24 months, from 69 (16) to 91 (9) in group I and from 70 (17) to 90 (15) in group II (means (SD)). There were also significant improvements in patellofemoral pain scores in both groups, from 13 (6) to 18 (5) in group I and from 14 (6) to 18 (4) in group II after 24 months. No difference was found between the groups in knee stability at the 24 month follow up. The IKDC score was identical in both groups at follow up. The operation took significantly longer for patients in group I (mean 94 (15)) than for those in group II (mean 86 (20)) (p = 0.03). The mean sick leave was 7.7 (6.2) weeks in group I and 12.3 (9.7) weeks in group II (p = 0.026), indicating that there may be a higher morbidity associated with the "all-inside" technique. It can be concluded that there were no significant differences between the two different techniques in terms of functional results, knee laxity, or postoperative complications. The results were satisfactory and the outcome was similar in both treatment groups.

Bioabsorbable tacks for arthroscopic treatment of recurrent anterior shoulder dislocation

Seventy-eight patients (82 shoulders) with symptomatic, recurrent anterior post-traumatic shoulder instability and Bankart lesions were operated on with bioabsorbable tacks (Suretac fixators). All the patients were followed by an independent observer, with a median follow-up period of 27 (21-63) months. The recurrence rate was 8/82 (10%). The median Rowe score was 93 (37-100) points. The median Constant score for the index shoulders was 90 (34-100) points, compared with 93 (80-100) points for 59 non-operated healthy shoulders from the same cohort (P=0.03). The external rotation in abduction was 93 (50-135) degrees compared with 105 (75-145) degrees for the control shoulders (P=0.0018). Arthroscopic shoulder stabilization using bioabsorbable Suretac fixators appears to produce reliable results if used in patients with post-traumatic shoulder instability and a Bankart lesion.

Injuries in the adolescent porcine spine exposed to mechanical compression

STUDY DESIGN

An experimental porcine study in which functional lumbar spinal units were tested in compression to failure. Biomechanical, radiographic, magnetic resonance imaging, and histological characteristics are described.

OBJECTIVES

To explain the different patterns of injury seen in adults and adolescents resulting from traumatic injury to the vertebrae and to explain the mechanism behind traumatic displacement of the ring apophysis seen in athletes.

SUMMARY OF BACKGROUND DATA

Recent investigations of the spine in adolescent who have sustained trauma have shown injuries to the growth zone, whereas studies of adults have shown injuries to the vertebral body. A higher frequency of abnormalities in the discs, the vertebral bodies, the endplates, and the ring apophyses has been demonstrated in athletes with high loads on the spine. There is controversy over the etiology of these changes.

METHODS

Twelve functional lumbar spinal units (vertebra-disc-vertebra) obtained from six young male pigs were tested in compression to failure. All units were examined with plain radiography and magnetic resonance imaging before and after compression. After the compression, histologic samples were taken from the injury site.

RESULTS

Identical traumatic changes were seen in all functional lumbar spinal units, i.e., fracture in the endplate through the growth zone posteriorly and displacement of the anulus fibrosus with a bony fragment at the point of insertion of the vertebra. The nucleus pulposus was ruptured and displaced through the fracture line in all cases. The injuries were not seen on radiographs but were detected on magnetic resonance images, as confirmed on microscopic and histologic examination.

CONCLUSION

This study shows that the weakest part of the lumbar spine of the juvenile pig, when compressed, is the growth zone and the junction between the point of insertion of the anulus fibrosus and the vertebra. This location of weakness may explain the high frequency of disc degeneration and "persisting apophysis" seen in the spine of athletes.

Injuries in adolescent spine exposed to compressive loads: an experimental cadaveric study

In a cadaveric experiment, 16 functional spinal units (FSUs) obtained from 7 subjects with a mean age of 16.3 years were tested in compression to failure. The deformation rate was 5 mm/min. The bone mineral content (BMC) in the vertebrae was determined by using dual-photon absorptiometry (DPA). In 15 of the FSUs, traumatic changes were registered. Three different types of changes were seen. In nine vertebrae, there was a rupture in the cartilaginous end plate, in 12, a separation of the end plate from the vertebral body, and in three vertebrae, a compression fracture was registered. A close relation was found between BMC and the ultimate force (r2 = 0.63), the ultimate displacement (r2 = 0.73), and the energy absorption (r2 = 0.74). The weakest part of a spinal segment in this experimental situation is the growth plate.

Intramuscular pressure in the leg and thigh related to tensile strap force during knee brace wear. An experimental study in man

The effects of a functional knee brace on intramuscular pressure in the leg and thigh were measured in eight subjects with a mean age of 32 years. Pressures in the tibialis anterior and rectus femoris muscles were recorded without a knee brace and with a brace applied with strap tensile force of 25 N, 50 N, and a force preferred by the subject. External compression caused by the brace significantly increased intramuscular pressures at rest and muscle relaxation pressure during exercise in the leg and thigh muscles. Pressure in the tibialis anterior muscle increased 3 to 10 times, to mean values between 17.5 and 41 mm Hg, depending on the tensile force of the straps used at brace application. Corresponding mean pressure values in the rectus femoris muscle were between 17.5 and 32.5 mm Hg. Mean pressures in the standing subject varied between 37 and 62 mm Hg. Our study showed that intramuscular pressure at rest and muscle relaxation pressure during exercise in the tibialis anterior and the rectus femoris muscles increased significantly in the braced limb. Local blood perfusion pressure in the supine subject decreased significantly, by 16% to 42%, in the compressed muscles.

Closing patellar tendon defects after anterior cruciate ligament reconstruction: absence of any benefit

The most common graft in anterior cruciate ligament (ACL) surgery involves using the central one-third of the patellar tendon. Knowledge concerning the postoperative disability after harvesting the patellar tendon is, however, limited. The aim of this study was to evaluate the impact patellar tendon suture and bone grafting of the patellar bone defect might have in terms of functional outcome and patellofemoral pain after harvesting the bone-tendon-bone graft, compared with leaving the harvested site non-sutured and non-grafted. Sixty patients, scheduled for arthroscopically assisted ACL reconstruction, were randomly allocated to two groups. In group I, suture of the patellar tendon and bone grafting of the patellar defect were performed. In group II, the tendon gap and the patellar defect were left open. Preoperatively, there was no significant difference between the groups when comparing objective knee stability, as measured with a KT-1000 laxity meter, Lysholm score, Tegner activity level, IKDC score, or patello-femoral pain score. Both groups had a significantly improved Lysholm score at the 2-year follow-up, without any difference between them. Tegner's activity level was significantly lower at follow-up, compared with the pre-injury level in both groups. The patellofemoral pain score improved significantly after the reconstruction, without any difference between the groups. Ultrasonography did not reveal any difference between the groups in terms of healing of the tendon gap. This study revealed no differences in donor site morbidity, functional outcome, patellofemoral pain score or knee joint stability between the two treatment groups. The conclusion is that suture of the patellar tendon and bone grafting of the patellar defect do not improve the functional results or reduce donor site morbidity after arthroscopically assisted ACL.

Analgesic effects of intra-articular morphine during and after knee arthroscopy: a comparison of two methods

The objective of this study was to compare the analgesic effects of intra-articularly administered bupivacaine with bupivacaine/morphine during and after therapeutic knee arthroscopy. In a prospective, randomized study, 50 patients with clinical signs of medial meniscal injury were allocated to two groups, A and B. The patients in group A received 40 mL of 0.25% bupivacaine while the same dose of bupivacaine combined with 1 mg of morphine sulphate was administered in group B. Pain was estimated using the visual analogue scale (VAS) during surgery and at 2, 4, 6, and 24 hours after the operation was completed. Supplementary analgesic requirements were also registered, as well as the patients' overall rating of the entire procedure. The pain scores were significantly lower in Group B throughout the whole postoperative observation period. However, no significant differences were found between the two groups in terms of intraoperative pain scores, supplementary analgesic requirements, or the overall rating of the procedure. This study provides evidence that arthroscopic surgery can be performed in a safe manner after intra-articularly administered bupivacaine with or without low-dose morphine. The combination of low-dose morphine and bupivacaine did, however, produce a superior postoperative analgesic effect during the 24 hours following knee arthroscopy compared with bupivacaine alone.

Postoperative analgesic effects of an external cooling system and intra-articular bupivacaine/morphine after arthroscopic cruciate ligament surgery

The aim of this study was to evaluate the analgesic effect of an external cooling system with or without the combined effect of intra-articularly administered bupivacaine/morphine after arthroscopic anterior cruciate ligament (ACL) reconstruction. Fifty patients with isolated ACL insufficiency operated on under general anaesthesia were randomized to three different postoperative treatment groups. Group I was treated with the cooling system during the first 24 h after surgery and an intra-articular injection of 20 ml of physiological saline given at the completion of surgery; in group II, the cooling system was combined with an intra-articular injection of 20 ml bupivacaine 3.75 mg/ml and 1 mg of morphine at the end of the operation; while group III (placebo group) received an intra-articular injection of 20 ml of physiological saline at the completion of surgery. Pain was assessed using a visual analogue scale (VAS) at 1, 2, 4, 6, 24 and 48 h postoperatively. Supplementary analgesic requirements were registered. In group I 80% (16/20) and in group II 90% (18/20) of the patients were satisfied with the postoperative pain control regimen (NS). This was significantly better than in group III, where 30% (3/10) were satisfied. The pain scores were significantly lower in the two treatment groups compared with the placebo group during the entire postoperative period. The pain score was significantly lower in group II than in group I at 24 and 48 h after surgery. The supplementary analgesic requirements were also lower in the two treatment groups compared with the placebo group. No complications due to the use of the cooling system or the intra-articular injections of bupivacaine/morphine were observed. The external cooling system used in this study provides an effective method of obtaining pain relief after arthroscopic surgery. The combination with an intra-articular injection of morphine and bupivacaine results in a slightly greater analgesic effect than the cooling system alone.

"Corynebacterium aquaticum" wound infection after high-pressure water injection into the foot

The organisms presently named "Corynebacterium aquaticum" have their natural habitat in water and are increasingly often isolated in clinical specimens, but are very seldom the proven cause of infection. A case of a 24-year-old man with a "C aquaticum" wound infection secondary to a high-pressure water injection injury in the foot is described. Cefadroxil and cefuroxime were used for treatment.

Postoperative analgesic effects of intra-articular bupivacaine and morphine after arthroscopic cruciate ligament surgery

Intra-articular administration of local anaesthetics such as bupivacaine can produce short-term postoperative analgesia in patients undergoing diagnostic arthroscopy or arthroscopic meniscectomy. A peripheral anti-nociceptive effect may also be induced by the administration of intra-articular opiates interacting with local opioid receptors in inflamed peripheral tissue. In the present study we aimed to study the analgesic effects of intra-articularly given bupivacaine and morphine sulphate (as well as the combination of both drugs) on postoperative pain. In a prospective, randomized, double-blind manner 40 patients received one of the following: (a) morphine (1 mg in 20 ml NaCl), (b) bupivacaine (20 ml, 0.375%), (c) combination of both or (d) saline (20 ml, control group) intra-articularly at the end of arthroscopic anterior cruciate ligament (ACL) reconstruction. The postoperative pain was assessed via a visual analogue scale (VAS) during the first 48 h after surgery, and supplemental analgesic requirements were noted. All comparisons were made versus the control group receiving saline. The pain scores were significantly lower in the morphine group at 24 and 48 h, and in the bupivacaine group at 2, 4 and 6 h after surgery. In the group that received a combination of both bupivacaine and morphine, the pain scores were significantly reduced throughout the whole postoperative observation period. No side-effects or complications from therapy were seen in any of the groups. The conclusion of this study is that intra-articular morphine is effective in the postoperative period after arthroscopic ACL reconstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a functional knee brace on leg muscle function

The effects of a functional knee brace on local intramuscular pressures and on calculated blood perfusion pressure in the tibialis anterior muscle of the legs of six volunteers were determined. Torque generation during dorsiflexion of the ankle joint was measured with a Kinetic Computerized ergometer, and the time to elicit muscle fatigue during exercise was recorded. For each experimental subject studies compared right with left unbraced legs, then right braced with left unbraced legs, and finally right unbraced with left braced legs. In the braced leg, intramuscular pressure at rest and muscle relaxation pressure during exercise were significantly higher, and the time to elicit muscle fatigue was 35% shorter. The calculated local blood perfusion pressure was lower because of the increased muscle relaxation pressure. We conclude that the increased muscle relaxation pressure during exercise caused by a knee brace is a possible explanation for the premature development of muscle fatigue in the braced leg.

Partial rupture of the patellar ligament. Results after operative treatment

Partial rupture of the patellar ligament, also known as jumper's knee, is defined as a repetitive overload lesion at the bone-ligament junction at the lower patellar pole. It is found mainly in athletes and is caused either by microruptures or partial macroruptures of the proximal part of the ligament. The abnormal anatomical lesion is focal degeneration, microruptures and macroruptures, and devitalized tissue at the insertion of the patellar ligament. Proliferation and neovascularization are often found, as well as degeneration and incomplete tissue healing. Surgical treatment is indicated only if a prolonged and well-supervised conservative treatment program fails. We operated on 78 patients with jumper's knee, by carefully removing the abnormal tissue from the ligament. At follow-up examination, 71 of 78 patients had excellent or good functional results and complete resumption of sports activities. Objective measurements of thigh muscle strength using a Cybex II dynamometer correlated with the functional results at a low angular velocity.