The effect of intraoperative fluoroscopy on the accuracy of femoral tunnel placement in single-bundle anatomic ACL reconstruction.

PURPOSE: The purpose of the current study was to investigate the potential effect of intraoperative fluoroscopy on the accuracy of femoral tunnel placement in anatomic ACL reconstruction, using an ideal anatomic point as reference and evaluating postoperative tunnel placement based on 3D CT. METHODS: An experienced ACL surgeon, using the anatomic approach for femoral tunnel placement, relying on intraarticular landmarks and remnants of the torn ACL-and novel to the fluoroscopic assist-was introduced to its use. A prospective series of patients was included where group 1 (without fluoroscopy) and group 2 (with fluoroscopy) both had postoperative CT scans so that femoral tunnel position could be evaluated and compared to an ideal tunnel centre based on anatomic studies by using the Bernard and Hertel grid. RESULTS: Group 2, where fluoroscopy was used, had a mean femoral tunnel that was closer to the ideal anatomic centre than group 1. In the Bernard and Hertel grid, the distance in the high-low axis (y-axis) was found significantly closer (P = 0.001), whilst the deep-shallow axis (x-axis) and a total absolute distance were not significantly closer to the ideal described anatomic centre. CONCLUSIONS: Intraoperative fluoroscopy was found effective as an aid for placing the femoral tunnel in a more accurate position, as compared to a desired anatomic centre. Although the concept of the "one-size-fits-all" approach for tunnel placement is debatable, the avoidance of grossly misplaced tunnels is the benefit of using fluoroscopy during ACL reconstruction. The authors hold that fluoroscopy is readily available, safe and easy to use and therefore a good aid in the anatomic approach for graft tunnel placement, for example, in a learning situation, in revision cases and when performing low volumes of such surgery. LEVEL OF EVIDENCE: III.

Symptoms and function in patients with articular cartilage lesions in 1,000 knee arthroscopies.

PURPOSE: Focal chondral lesions of the knee are commonly occurring. A lot is known about their frequency, size and localisation in arthroscopic series, but less about the symptoms they elicit and little about how the arthroscopic findings and symptoms correlate. The purposes of the present study included to investigate the relationship between articular cartilage lesion factors and patient factors, and to compare the symptoms and function of cartilage lesion patients to those of patients with a deficient ACL. METHODS: A prospective registration was conducted of preoperative data including Lysholm knee score and perioperative findings in 1,000 consecutive patients undergoing an arthroscopic procedure of the knee-including microfracture of articular cartilage defects and ACL reconstructions. RESULTS: Chondral or osteochondral lesions were found in 57 % of the arthroscopies. The mean Lysholm score in this subgroup was 55. The mean Lysholm score was significantly lower in women (50, SD 19) compared to men (59, SD 18, p < 0.001). Among the chondral lesion factors, only kissing (vs. non-kissing) lesions and multiple (vs. single) lesions influenced symptoms and function to a more than negligible degree. Microfracture in one or two articular cartilage defects was performed in 187 patients. The microfracture group had a significant lower mean Lysholm score (54, SD 18) than a group of patients (N = 71) undergoing ACL reconstruction group (67, SD 17, p < 0.001). CONCLUSION: The study confirms that articular cartilage lesions are both common and cumbersome. Women seem to have more problems than men, whereas chondral lesion factors-such as localisation and size-seem to influence symptoms and function to a small degree. These aspects should be addressed when designing outcome studies, and should also be of interest to the orthopaedic surgeon-in the day-by-day clinical work. When treating these patients, our prime focus need to be on knee function rather than the cartilage defect as the relationship between the latter and the former is unclear. LEVEL OF EVIDENCE: Case-control study, Level III.

The effect of feedback from post-operative 3D CT on placement of femoral tunnels in single-bundle anatomic ACL reconstruction.

PURPOSE: To evaluate the effect of feedback from post-operative 3D CT in the learning process of placing the femoral graft tunnel anatomically using the anteromedial (AM)-portal technique in single-bundle anterior cruciate ligament (ACL) reconstruction. METHODS: An experienced knee surgeon converting from transtibial to AM-portal technique was offered post-operative feedback on tunnel placement. Three groups of patients were included: transtibial drilling, (AM1) anteromedial drilling without feedback and (AM2) anteromedial drilling with post-operative CT feedback. Intra-articular landmarks were used as the only guidance for tunnel placement. Tunnel position was compared to an ideal anatomical ACL position using the Bernard and Hertel grid and visual feedback was given on tunnel placements. The effect of feedback was measured as the distance from the anatomical centre, and spread of tunnel placements on post-operative CT performed feedback was initiated. RESULTS: When comparing the femoral tunnel placement to an ideal anatomical centre, there was an improvement in the mean tunnel position after (A) changing from a transtibial to an anatomical technique and a further improvement after (B) initializing the radiological feedback. There was a great variation of femoral tunnel localizations when initially only using intra-articular landmarks as guidance for tunnel placement--this variation, however, converged towards the anatomical centre throughout the feedback period and the AM2 group had a femoral tunnel closer (P = 0.001) to the anatomical centre than the AM1 group. CONCLUSIONS: Post-operative 3D CT is effective in the learning process of placing femoral tunnels anatomically by giving post-operative feedback on tunnel placement. Bony landmarks and ACL remnants were found unreliable as the only guidance for femoral tunnel placement in the AM-portal technique-therefore, the use of an aid is recommended to reduce unwanted tunnel variations in a learning phase. LEVEL OF EVIDENCE: Cohort Study, Level III.

Equal cartilage repair response between autologous chondrocytes in a collagen scaffold and minced cartilage under a collagen scaffold: an in vivo study in goats.

Cell-free methods for cartilage tissue repair have recently gained increased focus. One method to supply a chondrogenic cell source is to apply freshly harvested cartilage tissue to the defects area and to retain the tissue for cell outgrowth. The present study aims to investigate the cartilage repair response of autologous cartilage chips or chondrocytes in combination with a collagen membrane in a goat femoral condyle full thickness cartilage defect model. Fully 16 defects in 8 adult goats were used for the study. A total of 6 mm full-thickness cartilage defects in the femoral condyles were randomized to collagen membrane matrix scaffold with chondrocytes and minced cartilage placed under collagen membrane scaffold. Animals were followed for 4 months. No difference was found in O'Driscoll and Pinada histology scores, tissue filling (35%), or repair tissue stiffness between the two groups. This animal study demonstrated no difference in cartilage repair between the two different techniques. The general tissue regeneration was limited probably due to the early time point of investigation and the challenging mechanical environment.

Synthetically tuneable biomimetic artificial photosynthetic reaction centres that closely resemble the natural system in purple bacteria.

Porphyrin-based photosynthetic reaction centre (PRC) mimics, ZnPQ-Q2HP-C60 and MP2Q-Q2HP-C60 (M = Zn or 2H), designed to have a similar special-pair electron donor and similar charge-separation distances, redox processes and photochemical reaction rates to those in the natural PRC from purple bacteria, have been synthesised and extensive photochemical studies performed. Mechanisms of electron-transfer reactions are fully investigated using femtosecond and nanosecond transient absorption spectroscopy. In benzonitrile, all models show picosecond-timescale charge-separations and the final singlet charge-separations with the microsecond-timescale. The established lifetimes are long compared to other processes in organic solar cells or other organic light harvesting systems. These rigid, synthetically flexible molecules provide the closest mimics to the natural PRC so far synthesised and present a future direction for the design of light harvesters with controllable absorption, redox, and kinetics properties.

Intra-articular glucocorticoid, bupivacaine and morphine reduces pain, inflammatory response and convalescence after arthroscopic meniscectomy.

Convalescence after arthroscopic meniscectomy is dependent on pain and the inflammatory response. The aim of the study was therefore to investigate the effect of intra-articular bupivacaine + morphine + methylprednisolone versus bupivacaine + morphine or saline on postmeniscectomy pain, mobilisation and convalescence. In a double-blind randomized study 60 patients undergoing arthroscopic meniscectomy were allocated to intra-articular saline, intra-articular bupivacaine 150 mg + morphine 4 mg or the same dose of bupivacaine + morphine + intra-articular methylprednisolone 40 mg. All patients were instructed to resume normal activities immediately after operation. Pain during movement and walking, leg muscle force and joint effusion, use of crutches and duration of sick leave were assessed. Combined bupivacaine and morphine significantly reduced pain, time of immobilisation and duration of convalescence. Addition of methylprednisolone further reduced pain, use of additional analgesics, joint swelling and convalescence, improved muscle function and prevented the inflammatory response (acute phase protein) (P < 0.05). A multimodal analgesic and anti-inflammatory treatment may enhance post-arthroscopic convalescence, which depends on the trauma induced inflammatory response and pain.

Attachment of alkyltrichlorosilanes to the terminal 3,5-dihydroxyphenyl moiety of a self-assembled thiol monolayer on gold.

The synthesis of 5-(6-mercaptohexyloxy)-1,3-dihydroxybenzene and the formation of a self-assembled monolayer on polycrystalline gold using this compound are described. Methyltrichlorosilane and (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane were attached to the 3,5-dihydroxyphenyl terminus of the monolayer. The modified surfaces were studied by contact angle measurement, XPS, and cyclic voltammetry. High contact angles of 119 degrees -128 degrees were observed for the semifluoroalkylsilyl-functionalized monolayer. These high contact angles were maintained after subjecting the surface to, e.g., boiling in water or heating in air to 300 degrees C. Characterization of the silane-modified monolayers by XPS indicated more than one layer of silane present at the top of the monolayer. The thickness was reduced after boiling the cross-linked monolayers in H(2)O, however, maintaining high contact angles. Cyclic voltammetry studies revealed that the semifluoroalkylsilyl-functionalized surface showed a higher blocking capability and a higher electrochemical stability than the parent monolayer.

An electrochemical quartz crystal microbalance study of the etching of gold surfaces in the presence of tetramethylthiourea.

The oxidation of tetramethylthiourea (TMTU) at gold electrodes in acetonitrile, leading to dissolution of the electrode, has been studied by electrochemical methods and by an electrochemical quartz crystal microbalance (EQCM). TMTU in acetonitrile readily adsorbs at gold electrodes and an estimated coverage of 5.5 x 10(-10) mol cm(-2) (30 A2 per molecule) was measured electrochemically. Nevertheless, the oxidation of TMTU in solution is a diffusion-controlled process and is strongly influenced by the electrode material, as observed by comparison of gold electrodes with glassy carbon and platinum working electrodes. In the absence of TMTU, EQCM cyclic voltammetry experiments showed dissolution of gold through a 1e- oxidation process at potentials more positive than 1.20 V vs saturated calomel electrode (SCE). Potential step and cyclic voltammetry EQCM experiments performed using gold surfaces in the presence of TMTU revealed TMTU-assisted etching of gold at potentials as low as 0.35 V vs SCE. In the potential region from 0.35 to 1.20 V the current response of TMTU oxidation mimics the response expected for a redox-active species in solution, including the presence of a mass-transfer-limited region, which supports the conclusion that the etching process in this potential region is initiated by the oxidation of TMTU at the gold surface. The current efficiency of the TMTU-assisted etching was found to vary between 12 electrons per gold atom dissolved (e/Au) (E = 0.50 V vs SCE) and 2 e/Au (0.90 V < E < 1.20 V). At potentials <0.90 V the dominant electrochemical process is the formation of TMTU+, whereas at higher potentials the etching of the gold surface by formation of a Au(I)-TMTU+ species becomes equally important. At potentials above 1.20 V the etching is no longer dependent on the diffusion of TMTU and the e/Au value approaches 1.

Corneal endothelial cell changes associated with cataract surgery in patients with type 2 diabetes mellitus.

PURPOSE: To investigate the corneal endothelial cell density and morphology in patients with and without diabetes after phacoemulsification with intraocular lens implantation. METHODS: A clinical prospective study including 30 patients with type 2 diabetes and 30 control patients without diabetes scheduled to undergo cataract surgery. No difference in preoperative age was observed between the 2 groups (P = 0.90). Sample size was based on a power calculation (power 0.90; P = 0.05). The patients without diabetes had a casual blood glucose test performed to disclose undetected diabetes. The patients with diabetes had a serum glycosylated hemoglobin (HbA1c) test performed to reveal the glycemic control. The endothelial cell density, variation in endothelial cell size (CV), percentage of hexagonal cells, and central corneal thickness (CCT) were recorded at baseline and at 3 months postoperatively. RESULTS: The mean decrease in endothelial cell density at 3 months in the diabetic group was 154 cells per square millimeter (6.2%) and 42 cells per square millimeter (1.4%) in the control group. The difference in cell loss between the 2 groups was significant (P = 0.04). A significant decrease in the percentage of hexagonal cells was also seen in the diabetic group (P = 0.01). There was no statistically significant change in CV or CCT. Visual acuity increased significantly and equally in the 2 groups. CONCLUSIONS: The present study reveals a significantly greater loss of corneal endothelial cells in a diabetic group under good glycemic control, compared with nondiabetic group 3 months after phacoemulsification. The morphological changes in the endothelial cells in patients with well-controlled diabetes were not reflected in impaired function as judged by CCT.

Intraoperative floppy iris syndrome (IFIS): a practical approach to medical and surgical considerations in cataract extractions.

Intraoperative floppy iris syndrome (IFIS) during cataract surgery is characterized by iris fluttering, iris prolapse towards the incisions, and a progressive pupillary constriction leading to high rates of complications. The syndrome has been reported following the treatment of benign prostatic hyperplasia with α-1(a) adrenergic receptor inhibitors, especially tamsulosin. The present paper describes the syndrome and discusses its pharmacological background. Several techniques to prevent and to deal with the syndrome are presented.

Cartilage repair with chondrocytes in fibrin hydrogel and MPEG polylactide scaffold: an in vivo study in goats.

Polylactic acid polymers have been used extensively as biomaterials and have shown promising properties for cartilage tissue engineering. Numerous scaffold materials exist and the optimal scaffold needs to be identified. We have tried to assess the possibilities for cartilage repair by the use of two different scaffold techniques; autologous chondrocytes in a fibrin hydrogel and a novel MPEG-PLGA scaffold, where autologous chondrocytes are immobilized within the MPEG-PLGA scaffold by a fibrin hydrogel. Twenty adult goats were used for the study. A 6 mm circular full-thickness cartilage defect was created in both medial femoral condyles. The defects were randomized to the following four treatment groups. (1) Empty defect (control). (2) Subchondral drilling (control). (3) Fibrin hydrogel with autologous chondrocytes. (4) Fibrin hydrogel/chondrocyte solution in a MPEG-PLGA porous scaffold. Animals were followed for 4 month. Eight defects in each treatment group completed the study. ICRS macroscopic scoring (0-12). Indentation test was performed to assess stiffness of repair tissue. Histological analyses was performed using O'Driscoll and Pineda cartilage scores as well as percentage tissue filling of the defects. The MPEG-PLGA/chondrocytes scaffold was the superior treatment modality based on the macroscopic surface score, histological scores and defect filling. The mechanical test demonstrated no difference between treatment groups. The MPEG-PLGA/chondrocyte composite demonstrated significantly better cartilage repair response than empty defects, osteochondral drilling and fibrin hydrogel with chondrocytes. The novel MPEG-PLGA scaffold in combination with chondrocytes need further studies with respect to longer follow-up times.

Electrochemical properties of mixed self-assembled monolayers on gold electrodes containing mercaptooctylhydroquinone and alkylthiols.

Mixed self-assembled monolayers of 2-(mercaptooctyl)hydroquinone (QH2) and alkylthiols were formed on gold electrodes in EtOH and the redox process of the hydroquinone moiety of QH2 was characterized by cyclic voltammetry (CV) in 0.1 M H(2)SO(4). The monolayers were formed at a series of QH2:alkylthiol ratios and the QH2:alkylthiol ratio in solution was compared to the electrochemical response from QH2 in the obtained monolayer. Mixed monolayers of QH2 with hexylthiol, dodecylthiol, and octadecylthiol were studied. The length of the alkylthiol is crucial for the electrochemical response from QH2 in the monolayer. The total concentration of thiols during monolayer formation and incubation times were also studied and low concentrations of < 2.5 mM and long incubation times gave rise to lower peak separation, lower peak half widths in the CVs of the mixed monolayers, and lower background current. The stability of a pure QH2 monolayer and a 1:4 QH2:hexylthiol monolayer toward high potentials of up to 1.5 V versus Ag/AgCl was also studied and it was observed that the mixed monolayer is significantly more stable than the pure QH2 monolayer.

The influence of ultrasound on the mechanical properties of healing tendons in rabbits.

BACKGROUND: Therapeutic ultrasound is commonly used for treatment of injuries to tendons, ligaments and joint capsules. Opinions still differ, however, as to the beneficial effects of ultrasound treatment of the above-mentioned conditions. METHODS: We studied the effect of various ultrasound intensities on the healing of tenotomized, sutured and immobilized Achilles tendons of adult rabbits. Different intensities of pulsating ultrasound (0, 50, 100, 200, 500, 750, 1000 and 2000 mW/cm2, frequency 3 MHz) were given over the healing tendons for 5 min daily, using a gel as the coupling agent between the ultrasound probe and the skin. Eleven days after the tenotomy, the healing tendons were analyzed in a materials testing machine. RESULTS: The extensibility of the healing tendons was greater after sonication at an intensity of 2000 mW/cm2 than after 50 mW/cm2. We found no significant effect on the load at rupture and normalized load at rupture of the ultrasound-treated healing tendons compared with mock-sonicated healing tendons. A gradual decline was observed, however, in the stiffness and collagen content of the healing tendons with increasing intensity of the ultrasound treatment. INTERPRETATION: The pulsating ultrasound treatment applied did not improve the mechanical properties of healing Achilles tendons at day 11 after the operation. On the other hand, a slight decline in stiffness was observed with increasing intensity of ultrasound treatment.

[Surgery on articular cartilage: from debridement to tissue engineering]. / Ledbruskkirurgi: fra skylning til tissue engineering.

Articular cartilage is a complex tissue with a limited endogenous repair capacity. Surgical strategies to stimulate repair of damaged cartilage are presently evolving extensively. New techniques based on tissue-engineering principles with cultured cells and scaffolds are challenging established techniques based on generating a repair response from the bone marrow. This paper reviews treatments such as debridement, marrow-stimulating techniques, osteochondral transplantation and autologous chondrocyte transplantation. Debridement and marrow stimulation can provide significant relief of symptoms. Recently, randomized studies have uncovered some of the clinical effects of the new biotechnology-based surgical methods. However, no significant advances over the established surgical techniques have been developed.

Combined intra-articular glucocorticoid, bupivacaine and morphine reduces pain and convalescence after diagnostic knee arthroscopy.

We studied the effect of intra-articullar saline vs. bupivacaine + morphine or bupivacaine morphine + methylprednisolone after diagnostic knee arthroscopy. In a double-blind randomized study, 60 patients undergoing diagnostic knee arthroscopy without a therapeutic procedure were allocated to groups receiving intra-articular saline, intra-articular bupivacaine 150 mg + morphine 4 mg or the same dose of bupivacaine + morphine + intra-articular methylprednisolone 40 mg at the end of arthroscopy during general anesthesia. All patients were instructed to resume normal activities immediately after the procedure. Pain during movement and walking, leg muscle force and joint effusion, use of crutches and duration of sick leave were assessed. A combination of bupivacaine and morphine reduced pain, duration of immobilization and of convalescence. The addition of methylprednisolone further reduced pain, use of more analgesics, joint swelling and convalescence.