Hermann O. Mayr

Arthrofibrosis following ACL reconstruction--reasons and outcome.

IntroductionArthrofibrosis is a complication that severely influences the clinical outcome after anterior cruciate ligament (ACL) reconstruction. This retrospective clinical study analyses risk factors and outcome after arthrolysis in a large population.Material and methodsTwo hundred twenty-three patients who had undergone arthrolysis after ACL reconstruction were examined. Range of motion (ROM) was reduced due to arthrofibrosis of the joint in 70% (n=156). Other reasons, such as cyclops syndrome or osteoarthritis were found in 30% (n=67). The mean time interval between arthrolysis and follow-up was 4.29xa0years. We recorded timing of surgery, additional injuries, state of the knee before reconstruction, range of motion, pain during rehabilitation, beginning, duration and type of rehabilitation, severity and etiology of joint stiffness and the time between ACL reconstruction and revision. The present state of the knee was documented using the IKDC form.ResultsA significant correlation of arthrofibrosis and preoperative irritation (p<0.001), preoperative limited ROM (p=0.001), perioperative pain (p=0.046) and early beginning of muscle training (p=0.064) was found. Combination of a remaining loss of extension and development of degenerative joint disease was also significant (p=0.001). The decrease of sports activity compared with the level before ACL injury was highly significant (p<0,001). The criteria to minimize the risk of arthrofibrosis and the optimal timing of arthrolysis are pointed out.

Autologous chondrocyte implantation for the treatment of chondral and osteochondral defects of the talus: a meta-analysis of available evidence

PurposeWhile autologous chondrocyte implantation (ACI) has become an established surgical treatment for cartilage defects of the knee, only little is known about the clinical outcome following ACI for chondral or osteochondral lesion of the ankle. To evaluate efficiency and effectiveness of ACI for talar lesions was aim of the present meta-analysis.MethodsAn OVID-based literature search was performed to identify any published clinical studies on autologous chondrocyte implantation (ACI) for the treatment of pathologies of the ankle including the following databases: MEDLINE, MEDLINE preprints, EMBASE, CINAHL, Life Science Citations, British National Library of Health, and Cochrane Central Register of Controlled Trials (CENTRAL). Literature search period was from the beginning of 1994 to February 2011. Of 54 studies that were identified, a total of 16 studies met the inclusion criteria of the present meta-analysis. Those studies were systematically evaluated.ResultsAll studies identified represented case series (EBM Leven IV). 213 cases with various treatment for osteochondral and chondral defects with a mean size of 2.3xa0cm2 (±0.6) have been reported. A total of 9 different scores have been used as outcome parameters. Mean study size was 13 patients (SD 10; range 2–46) with a mean follow-up of 32xa0±xa027xa0months (range 6–120). Mean Coleman Methodology Score was 65 (SD 11) points. Overall clinical success rate was 89.9%.ConclusionsEvidence concerning the use of ACI for osteochondral and chondral defects of the talus is still elusive. Although clinical outcome as described in the studies available seems promising—with regard to a lack of controlled studies—a superiority or inferiority to other techniques such as osteochondral transplantation or microfracturing cannot be estimated.

Current Failure Mechanisms After Knee Arthroplasty Have Changed: Polyethylene Wear Is Less Common in Revision Surgery

BACKGROUNDnThe present study was designed to clarify which underlying indications can be currently considered the main reasons for failure after total knee arthroplasty as a function of time.nnnMETHODSnWe conducted a retrospective study that included all first revisions of total knee replacements during 2005 to 2010 at two high-volume arthroplasty centers. A revision was defined as the replacement of at least one prosthetic component. In the descriptive analysis, polyethylene wear, aseptic loosening, periprosthetic infection, malalignment, instability, arthrofibrosis, extensor mechanism deficiency, periprosthetic fracture, and retropatellar arthritis were given as the failure mechanism associated with an early, intermediate, or late time interval (less than one year, one to three years, and more than three years, respectively) after the index total knee arthroplasty.nnnRESULTSnThree hundred and fifty-eight revision total knee arthroplasties were included. Of those revisions, 19.8% were performed within the first year after the index arthroplasty. The most common indications for revision, besides aseptic loosening (21.8%), were instability (21.8%), malalignment (20.7%), and periprosthetic infection (14.5%). Revisions due to polyethylene wear (7%) rarely occurred. In the early failure group, the primary causes of revision were periprosthetic infection (26.8%) and instability (23.9%). In the intermediate group, instability (23.3%) and malalignment (29.4%) required revision surgery, whereas late failure mechanisms were aseptic loosening (34.7%), instability (18.5%), and polyethylene wear (18.5%).nnnCONCLUSIONSnAseptic loosening, instability, malalignment, and periprosthetic infection continue to be the primary failure mechanisms leading to revision surgery. Contrary to previous literature, the results in the present study showed a substantial reduction in implant-associated revisions such as those due to polyethylene wear. Failure mechanisms that occur persistently early and in the intermediate term, such as periprosthetic infection, instability, and malalignment, remain common causes of revision surgery.nnnLEVEL OF EVIDENCEnTherapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Microporous calcium phosphate ceramics as tissue engineering scaffolds for the repair of osteochondral defects: Biomechanical results

This work investigated the suitability of microporous β-tricalcium phosphate (TCP) scaffolds pre-seeded with autologous chondrocytes for treatment of osteochondral defects in a large animal model. Microporous β-TCP cylinders (Ø 7 mm; length 25 mm) were seeded with autologous chondrocytes and cultured for 4 weeks in vitro. Only the upper end of the cylinder was seeded with chondrocytes. Chondrocytes formed a multilayer on the top. The implants were then implanted in defects (diameter 7 mm) created in the left medial femoral condyle of ovine knees. The implants were covered with synovial membrane from the superior recess of the same joint. For the right knees, an empty defect with the same dimensions served as control. Twenty-eight sheep were split into 6-, 12-, 26- and 52 week groups of seven animals. Indentation tests with a spherical (Ø 3mm) indenter were used to determine the biomechanical properties of regenerated tissue. A software-based limit switch was implemented to ensure a maximal penetration depth of 200 μm and maximal load of 1.5 N. The achieved load, the absorbed energy and the contact stiffness were measured. Newly formed cartilage was assessed with the International Cartilage Repair Society Visual Assessment Scale (ICRS score) and histomorphometric analysis. Results were analysed statistically using the t-test, Mann-Whitney U-test and Wilcoxon test. Statistical significance was set at p<0.05. After 6 weeks of implantation, the transplanted area tolerated an indentation load of 0.05±0.20 N. This value increased to 0.10±0.06 N after 12 weeks, to 0.27±0.18 N after 26 weeks, and 0.27±0.11 N after 52 weeks. The increase in the tolerated load was highly significant (p<0.0001), but the final value was not significantly different from that of intact cartilage (0.30±0.12 N). Similarly, the increase in contact stiffness from 0.87±0.29 N mm-(1) after 6 weeks to 3.14±0.86 N mm(-1) after 52 weeks was highly significant (p<0.0001). The absorbed energy increased significantly (p=0.02) from 0.74×10(-6)±0.38×10(-6) Nm after 6 weeks to 2.83×10(-6)±1.35×10(-6) Nm after 52 weeks. At 52 weeks, the International Cartilage Repair Society (ICRS) scores for the central area of the transplanted area and untreated defects were comparable. In contrast, the score for the area from the edge to the centre of the transplanted area was significantly higher (p=0.001) than the score for the unfilled defects. A biomechanically stable cartilage was built outside the centre of defect. After 52 weeks, all but one empty control defect were covered by bone and a very thin layer of cartilage (ICRS 7 points). The empty hole could still be demonstrated beneath the bone. The histomorphometric evaluation revealed that 81.0±10.6% of TCP was resorbed after 52 weeks. The increase in TCP resorption and replacement by spongy bone during the observation period was highly significant (p<0.0001). In this sheep trial, the mechanical properties of microporous TCP scaffolds seeded with transplanted autologous chondrocytes were similar to those of natural cartilage after 52 weeks of implantation. However, the central area of the implants had a lower ICRS score than healthy cartilage. Microporous TCP was almost fully resorbed at 52 weeks and replaced by bone.

Instrumented Examination of Anterior Cruciate Ligament Injuries: Minimizing Flaws of the Manual Clinical Examination

The clinical examination is a basic language of orthopaedics; it is how orthopaedic surgeons communicate with one another. However, each surgeon speaks a different dialect that has been influenced by where and with whom that surgeon trained, as well as that persons own experiences. Because of the inherent variability in the magnitude, direction, and rate of force application during the clinical examination, manual arthrometers were developed in an attempt to more consistently quantify the clinical examination. Instrumented manual devices, such as the KT-1000 (MEDmetric, San Diego, CA), were the first to provide objective numbers to surgeons and researchers evaluating anteroposterior (AP) knee joint laxity. Although these devices provide surgeons with feedback related to the amount of force applied, the rate at which the force is applied is uncontrolled, resulting in a lack of reliability similar to that of the clinical examination itself. In addition to potential errors in measuring AP laxity, rotational laxity has proven to be very difficult to quantify. Robotic systems that make use of computer-driven motors to perform laxity testing have recently been developed to control the magnitude, direction, and rate of force application and thus improve the accuracy and reliability of both AP and rotational laxity evaluation. This review discusses the evolution of instrumented clinical knee examination over the past 3 decades and highlights the advantages and disadvantages of the various testing systems, as well as how current and future developments in this area may improve the field of orthopaedics by minimizing the flaws of the manual clinical examination.

Pre- versus postoperative intraarticular application of local anesthetics and opioids versus femoral nerve block in anterior cruciate ligament repair

Background: Often anterior cruciate ligament (ACL) reconstruction is performed as outpatient surgery. This requires a patient friendly postoperative pain management. Three common procedures were compared in this trial. Methods: In a prospective, randomized study the effect of postoperative pain management using preoperative intraarticular anesthesia (0.1xa0mg Fentanylxa0+xa08xa0ml Bupivacain 0.5%) was compared with postoperative intraarticular anesthesia (0.1xa0mg Fentanylxa0+xa08xa0ml Bupivacain 0.5%) and the femoralis 3-in-1 nerve block (20xa0ml Prilocain 1%xa0+xa020xa0ml Bupivacain 0.5%) in 157 patients who underwent arthroscopic ACL-plasty. Results: Preoperative intraarticular anesthesia and the femoralis 3-in-1 nerve block showed the same postoperative analgesia and satisfactory pain scores in most cases. Postoperative intraarticular anesthesia was less effective. Conclusion: Our data show that in anterior cruciate ligament reconstruction preoperative intraarticular analgesia with Bupivacain/Fentanyl is satisfactory and equal to the femoralis 3-in-1 nerve block with Bupivacain.

Revision of anterior cruciate ligament reconstruction with patellar tendon allograft and autograft: 2- and 5-year results

IntroductionThe most common failure reasons of an anterior cruciate ligament (ACL) graft are incorrect positioning of the drill channels and insufficient fixation. In many cases, one-stage revision with patellar tendon graft and the appropriate corrections are possible. For previous use of the ipsilateral patellar tendon third, an allograft seems favorable for reconstruction. So far, no study compared the results of revision surgery of autologous versus allogenous patellar tendon grafts for revision surgery of the ACL in a 5-year follow-up.Materials and methodsA retrospective study was conducted to analyze the clinical outcome and stability results 2xa0years (19.2xa0±xa05.8xa0months) and 5xa0years (68.8xa0±xa06.8xa0months) after revision of ACL reconstruction using middle-third patellar tendon allografts and autografts. The allografts were cleansed by mechanical means only. There were 15 patients in the allograft group and 14 in the autograft group. Patients with isolated re-rupture of the ACL graft were included in the study. Clinical results were evaluated by International Knee Documentation Committee 2000 forms (IKDC), Lysholm score, Tegner activity score, and visual analog scale. Stability was evaluated by means of KT-1000 arthrometer, Lachman test, and pivot-shift test. Location of drill holes was evaluated radiologically. Gonarthritis was graded according to Kellgren and Lawrence on the basis of radiographs.ResultsThere were no significant differences between the two groups in anterior translation, manual examination for stability, IKDC 2000 findings, Tegner activity score, or Lysholm score. Extension deficits were more frequent in the autograft group at the first follow-up (Pxa0=xa00.010). Lateral gonarthritis and femoral tunnel widening were more common in the allograft group at the second follow-up (Pxa0=xa00.049 and Pxa0=xa00.023, respectively). Pain on walking downhill was significantly more frequent in the allograft group at the second follow-up (Pxa0=xa00.027).ConclusionsThe functional results with allografts that had not undergone irradiation or chemical sterilization were comparable to those with autografts in ACL revision surgery. Allografts represent a good alternative to autogenous patellar tendons in revision surgery.

Mechanical tensile properties of the anterolateral ligament.

AbstractBackgroundIn a noticeable percentage of patients anterolateral rotational instabilities (ALRI) remain after an isolated ACL reconstruction. Those instabilities may occur due to an insufficiently directed damage of anterolateral structures that is often associated with ACL ruptures. Recent publications describe an anatomical structure, termed the anterolateral ligament (ALL), and suggest that this ligament plays a significant role in the pathogenesis of ALRI of the knee joint. However, only limited knowledge about the biomechanical characteristics and tensile properties of the anterolateral ligament exists.MethodsThe anterolateral ligament was dissected in four fresh-frozen human cadaveric specimens and all surrounding tissue removed. The initial length of the anterolateral ligament was measured using a digital caliper. Tensile tests with load to failure were performed using a materials testing machine. The explanted anterolateral ligaments were histologically examined to measure the cross-sectional area.ResultsThe mean ultimate load to failure of the anterolateral ligament was 49.90 N (± 14.62 N) and the mean ultimate strain was 35.96% (± 4.47%). The mean length of the ligament was 33.08 mm (± 2.24) and the mean cross-sectional area was 1.54 mm2 (± 0.48 mm2). Including the areal measurements the maximum tension was calculated to be 32.78 Nmm2n

Graft-dependent differences in the ligamentization process of anterior cruciate ligament grafts in a sheep trial

frac {N}{{mm}^{2}}

Simultaneous 3D Assessment of Glenohumeral Shape, Humeral Head Centering, and Scapular Positioning in Atraumatic Shoulder Instability: A Magnetic Resonance–Based In Vivo Analysis

n (± 4.04 Nmm2n