A new quantitative measure for radiologic osteoarthritis of the lateral knee compartment distinguishes patients with longstanding lateral meniscectomy from non-pathological knees.

PURPOSE: Common radiologic scores to evaluate knee osteoarthritis (OA) have been widely used but are descriptive and may lack objectivity. The aim of this study was to develop a quantitative and objective radiologic measure for the evaluation of lateral knee compartment OA. Furthermore, we tested the reliability of this new measure and its correlation to well-accepted radiologic scores. METHODS: This retrospective study was performed within the context of a multi-centre long-term follow-up (15-25 years) of a patient cohort after partial or total lateral meniscectomy (n = 36 knees). In addition, 99 radiographs of clinically and radiologically normal knees were obtained from a control group. Anteroposterior weight-bearing views (0°) and Schuss (45°) views were analysed. The joint height of the lateral knee compartment was measured on the lateral border (lateral joint space height) and in the centre (central joint space height, CJSH) and normalized with respect to the width of the lateral compartment (X). All measurements were taken independently by two observers, allowing for inter- and intra-observer reliability assessments. The results of the two groups were compared using an analysis of covariance. Finally, the correlations between the results and the Fairbank and Kellgren & Lawrence scores were determined using a Spearman ρ rank order correlation. RESULTS: The normalized joint space height in the centre of the compartment on the Schuss view (CJSH/X) showed the highest intra- (ICC = 0.980) and inter-observer reliability (ICC = 0.982). There was a significant difference in CJSH/X between the control (0.19 ± 0.05) and the meniscectomized knees (0.08 ± 0.07) (p < 0.001). CJSH/X showed a significant decline of 11 % per 10 years in the meniscectomy group. A negative correlation could be found between CJSH/X and the Fairbank (ρ = -0.751; p < 0.001) and Kellgren & Lawrence scores (ρ = -0.712; p < 0.001). A cut-off value of 0.14 of CJSH/X was defined-representing one standard deviation below the mean of the control group-from which measurements were considered as pathologic. CONCLUSION: The normalized joint space height measured in the centre of the lateral knee compartment from a Schuss view, CJSH/X, was highly reproducible and showed a significant correlation to established radiologic scores. This new measure has the advantage of being objective and dimensionless and thus independent of the size of the radiograph. The normative values provided by our healthy control knees are useful to help establish an early diagnosis of radiologic lateral knee compartment OA. LEVEL OF EVIDENCE: Retrospective diagnostic study, Level III.

Radiographic guided drilling of bony tibial tunnels for fixation of meniscus transplants using percentage references.

The objective of our investigation was to evaluate the precision of radiographic-guided tibial tunnel drilling for anatomical anchoring of meniscus transplants at the tibial insertion areas. In 20 cadaveric proximal tibiae, the meniscal insertions were dissected and their circumferences outlined. Standardized photographs of the tibial plateau were obtained. Applying established percentage values for radiographic determination of the meniscus insertion midpoints, tibial tunnels were drilled using a standard ACL-guide. Guide positioning was performed by using the midpoints as determined on standard AP and lateral radiographs. After tibial tunnel drilling, a second set of standardized photographs of the tibial plateau was obtained. Digital imaging permitted the superposition of pre- and postoperative images. Overlapping between the anatomical insertion areas and the tibial tunnel exit was determined, as well as the distance between the borders of the insertion areas and the tunnel exit. Insertion area and tunnel exit showed a mean overlapping of 59.8 ± 34.8% (anterior horn), respectively 62.4 ± 32.0% (posterior horn) for the lateral meniscus and of 88.4 ± 15.5% (anterior horn), respectively 60.3 ± 31.6% (posterior horn) for the medial meniscus. Mean distance between the borders of insertion area and tunnel exit was 2.0 ± 1.5 mm (anterior horn), respectively 2.0 ± 1.7 mm (posterior horn) for the lateral meniscus and 0.9 ± 0.9 mm (anterior horn), respectively 2.1 ± 1.4 mm (posterior horn) for the medial meniscus. Thus, a precise drilling of tibial tunnels at the anatomical insertions of the menisci can be obtained by positioning a standard ACL-guide under radiographic control in a cadaver setting. In advanced day-by-day clinic, this knowledge could facilitate the surgical technique for anatomical fixation of lateral and medial meniscus transplants.

Elution of gentamicin and vancomycin from polymethylmethacrylate beads and hip spacers in vivo.

BACKGROUND AND PURPOSE: Late infections after total hip arthroplasty are still a problem. Treatment procedures include resection arthroplasty with implantation of antibiotic-loaded beads or implantation of an antibiotic-impreganted spacer. However, little is known about antibiotic elution from bone cement beyond the first 2-3 postoperative days in humans. METHODS: 17 hip spacers (80 g PMMA, 1g gentamicin, and 4 g vancomycin) and 11 chains (40 g PMMA, 0.5 g gentamicin, and 2 g vancomycin) in 28 patients were studied. The release of both agents was measured in the drainage fluid on a daily basis. The drains were left in situ until less than 50 mL was produced per day. The elution of both antibiotics was determined by fluorescence polarization immunoassay. Systemic antibiotics were given postoperatively according to antibiogram. If possible, no gentamicin or vancomycin was given. RESULTS: Peak mean concentrations from beads and spacers were reached for gentamicin (1,160 (12-371) microg/mL and 21 (0.7-39) microg/mL, respectively) and for vancomycin (80 (21-198) microg/mL and 37 (3.3-72) microg/mL) on day 1. The last concentrations to be determined were 3.7 microg/mL gentamicin and 23 microg/mL vancomycin in the beads group after 13 days, and 1.9 microg/mL gentamicin and 6.6 microg/mL vancomycin in the spacer group after 7 days. Between the fifth and seventh day, an intermittent increase in elution of vancomycin from both beads and spacers and of gentamicin from spacers was noticed. No renal or hepatic dysfunction was observed. INTERPRETATION: Beads showed higher elution characteristics in vivo than the spacers due to their larger surface area; however, a great amount of inter-subject variability was seen for both beads and spacers. The inferior elution properties of spacers emphasize the importance of additional systemic antibiotics for this treatment procedure during the postoperative period. Future studies should clarify whether the dose of antibiotics or length of antibiotic therapy may be reduced in the case of bead implantation, without jeopardizing the control of infection.

The reproducibility of radiographic measurement of medial meniscus horn position.

PURPOSE: The objective of this investigation was to evaluate the possibility of locating and reproducing the tibial insertion areas of the anterior and posterior horns of the medial meniscus on preoperative radiographs according to an established method for the lateral meniscus. METHODS: In 20 tibia heads, we prepared anterior and posterior horn insertions and marked their circumference with radiopaque steel balls of 1.6 mm in diameter. Standardized anteroposterior and lateral radiographs were made. On these radiographs, different landmarks were defined, their distances measured (tibial width and depth, distance from lateral tibia border to meniscus insertion midpoint, distance from anterior tibia border to meniscus insertion midpoint, distance from anterior and lateral tibia border to medial intercondylar spine), and ratios determined. RESULTS: The anterior horn midpoint is located at 57.3% +/- 2.7% of tibial width and 12.0% +/- 1.0% of tibial depth, and the posterior horn midpoint is located at 56.5% +/- 1.6% of tibial width and 81.6% +/- 3.4% of tibial depth. The statistical analysis of these measures showed a precise and constant positioning of the medial meniscus insertions on the tibia plateau. We also found constant topographic relations to the medial intercondylar spine. CONCLUSIONS: The midpoints of both insertion areas of the medial meniscus have constant positions at 57.3% and 56.5% of tibial width and at 12.0% and 81.6% of tibial depth for the anterior and posterior horn, respectively. They can precisely and reproducibly be defined on radiographs. CLINICAL RELEVANCE: We have developed a technique for precise radiographic tibial horn determination, exact placement of the tibial tunnels, and thus reconstruction of meniscus insertion anatomy in medial meniscus transplantation.

The reproducibility of radiographic measurement of lateral meniscus horn position.

PURPOSE: The objective of our investigation was to evaluate whether it is possible to locate and reproduce the tibial insertion areas of the anterior and posterior horns of the lateral meniscus on preoperative radiographs. METHODS: In 20 tibia heads, we prepared anterior and posterior horn insertions and marked their circumference with radiopaque steel balls of 1.6 mm in diameter. Standardized anteroposterior and lateral radiographs were made. On these radiographs, different landmarks were defined, their distances measured (tibial width and depth, distance from lateral tibia border to meniscus insertion midpoint, distance from anterior tibia border to meniscus insertion midpoint, distance from anterior and lateral tibia border to lateral intercondylar spine), and ratios determined. RESULTS: The anterior horn midpoint is located at 45.1% +/- 1.3% of tibial width and 41.9% +/- 3.2% of tibial depth, and the posterior horn midpoint is located at 49.8% +/- 1.9% of tibial width and 72.1% +/- 2.3% of tibial depth. The statistical analysis of these measures showed a precise and constant positioning of the lateral meniscus insertions on the tibia plateau. We also found constant topographic relations to the lateral intercondylar spine. CONCLUSIONS: Anterior and posterior lateral meniscus horn insertions can be determined on radiographs with a high precision and reproducibility. CLINICAL RELEVANCE: We have developed a technique for precise radiographic tibial horn determination in lateral meniscus transplantation.

Extracorporeal shock wave therapy for tendinopathies.

Shock waves, as applied in urology and gastroenterology, were introduced in the middle of the last decade in Germany to treat different pathologies of the musculoskeletal system, including epicondylitis of the elbow, plantar fasciitis, and calcifying and noncalcifying tendinitis of the rotator cuff. With the noninvasive nature of these waves and their seemingly low complication rate, extracorporeal shock wave therapy (ESWT) seemed a promising alternative to the established conservative and surgical options in the treatment of patients with chronically painful conditions. However, the apparent advantages of the method led to a rapid diffusion and even inflationary use of ESWT; prospective, randomized studies on the mechanisms and effects of shock waves on musculoskeletal tissues were urgently needed to define more accurate indications and optimize therapeutic outcome. This review covers recent international research in the field and presents actual indications and results in therapy of musculoskeletal conditions with ESWT.