Christoph Becher

Results of Microfracture in the Treatment of Articular Cartilage Defects of the Talus

Background: The microfracture technique has been used successfully for the treatment of cartilage defects in the knee. The purpose of this study was to evaluate the microfracture technique in the treatment of osteochondral and degenerative chondral defects of the talus. Methods: In a prospective study, 30 ankles in 30 consecutive patients (17 men and 13 women; average age, 41 years; range 20 to 74 years) were treated with arthroscopic microfracture. Twenty patients had osteochondral defects and 10 had degenerative chondral defects. Patients were evaluated with clinical examination and MRI preoperatively and at 3, 6, 12, and 24 months postoperatively. Results: At a mean followup of 2 years (range 22 to 27 months), 29 patients were available for followup. The results for all ankles according to the Hannover Scoring System were 45% excellent, 38% good, and 17% satisfactory. Results in patients older than 50 years were not inferior to those in younger patients. Visual Analog Score revealed an average of 8 ± 2 for pain (preoperatively 3 ± 2; p ≤ 0.001), 8 ± 2 for function (preoperatively 3 ± 2; p ≤ 0.001) and 8 ± 2 for satisfaction (preoperatively 2 ± 2; p ≤ 0.001). MRI and arthroscopic assessment suggested the presence of cartilage in the microfractured area. Conclusions: At short-term followup, the microfracture technique appeared to repair severe cartilage damage with a good functional outcome. Age was not shown to be a limiting factor.

Dynamic versus static reconstruction of the medial patellofemoral ligament for recurrent lateral patellar dislocation

PurposeTo compare clinical and radiological outcomes of static and dynamic medial patellofemoral ligament (MPFL) reconstruction techniques.MethodsIn a retrospective, matched-paired, cohort analysis, 30 patients surgically treated for recurrent lateral patellar dislocation were divided into two groups of 15 patients matched for inclusion and exclusion criteria. The static technique group underwent rigid fixation of the gracilis tendon at the anatomic femoral MPFL insertion and the superomedial border of the patella; the dynamic technique group underwent detachment of the gracilis tendon at the pes anserinus with fixation to the proximal medial patellar margin via tunnel transfer obliquely through the patella. Kujala, Lysholm, and Tegner scores; pain level; and pre- and postoperative radiographic changes of patellar height, patellar tilt, and bisect offset were compared.ResultsNo significant between-group differences were found in mean Kujala, Tegner, Lysholm, or visual analogue scale scores or radiographic parameters. One case of resubluxation was observed in the dynamic group. All but one patient in each group would have been willing to undergo the procedure again.ConclusionsBoth techniques provided satisfactory short-term outcomes.Level of evidenceIII.

In vitro electro-mechanical characterization of human knee articular cartilage of different degeneration levels: A comparison with ICRS and Mankin scores

In the present study, the electro-mechanical properties of human knee articular cartilage were measured in vitro. An arthroscopic measurement tool was used to measure streaming potential integral (SPI), after which creep indentation tests were performed. Additionally, degradation level of the tissue was determined in accordance with the International Cartilage Repair Society (ICRS score), and hematoxylin/eosin and safranin O staining were performed to determine the Mankin score. Mechanical test results were evaluated both analytically and by means of a finite-element-optimized parameter identification procedure. The SPI was then correlated with poroelastic E modulus (r=0.563, p<0.008, n=22), natural logarithm of hydraulic permeability (r=0.374, p<0.095, n=22) and cartilage degeneration scores (ICRS and Mankin) (r=-0.749, p<0.000, n=22 and r=-0.409, p<0.059, n=22 respectively).

Translation and validation of the German version of the foot and ankle outcome score

PurposeOutcome assessment is critical in evaluating the efficacy of orthopaedic procedures. The Foot and Ankle Outcome Score (FAOS) is a 42-item questionnaire divided into five subscales, which has been validated in several languages. Germany has no validated outcome score for general foot and ankle pathology. The aim of this study was to develop a German version of the FAOS and to investigate its psychometric properties.Materials and methodsForward and backward translation was executed according to official guidelines. The final version of the FAOS was investigated in 150 patients with various foot and ankle disorders. All patients completed the FAOS, Short Form-36, numeric rating scales for pain and disability, and the Hannover questionnaire. The FAOS was re-administered after 1 week. Test–retest reliability, internal consistency, minimal detectable change, construct validity, and floor and ceiling effects were analyzed.ResultsTest–retest reliability and internal consistency of each subscale were excellent (intraclass correlation coefficient, 0.88–0.95; Cronbach’s α, 0.94–0.98). The minimal detectable changes of each subscale were 17.1–20.8 at the individual level and 2.0–2.4 at group level. There were moderate to strong correlations between FAOS subscales and physical outcomes and low to moderate correlations between FAOS subscales and mental outcomes. Floor and ceiling effects were not present.ConclusionThe German version of the FAOS is a reliable and valid instrument for use in foot and ankle patients.

Decrease in the expression of the type 1 PTH/PTHrP receptor (PTH1R) on chondrocytes in animals with osteoarthritis

BackgroundTo evaluate the expression of the type 1 PTH/PTHrP receptor (PTH1R) on chondrocytes from hyaline cartilage over the course of osteoarthritis (OA).MethodsIn 12 NZW rabbits, the anterior cruciate ligament (ACL) was resected to create anterior instability of the knee. In 12 control rabbits, only a sham operation, without resection of the ACL, was performed. Four animals from each group were killed at 3, 6, and 12 weeks. After opening the knee joint, OA was macroscopically graded and hyaline cartilage of the load-bearing area was evaluated histologically according to the Mankin scale and by immunostaining for PTH1R.ResultsThere was a positive linear correlation between the time after surgery and the macroscopic and histologic OA scores. The scores in the control group were constant over the time course. Immunostaining showed significantly less expression of PTH1R in the experimental compared to the control group after 6 (P < 0.05) and 12 weeks (P < 0.01). In the experimental group, a negative linear correlation between PTH1R expression and macroscopic and histologic grades was found.ConclusionsThe results show an in vivo decrease in the expression of PTH1R on chondrocytes over the time course of OA. Further studies are needed to evaluate whether new treatment approaches could evolve from this knowledge.

The Achilles tendon

The History of the Tendo Achillis and Its Rupture.- The Anatomy of the Achilles Tendon.- Biomechanics of the Achilles Tendon.- Imaging of the Achilles Tendon.- Etiology and Epidemiology of Achilles Tendon Problems.- Paratendinopathy of the Achilles Tendon.- Tendinopathy of the Main Body of the Achilles Tendon.- Custom Foot Orthotic Management in Achilles Tendinopathy.- Percutaneous Surgical Management of Achilles Tendinopathy.- Open Surgery for Achilles Tendinopathy.- Flexor Hallucis Longus Augmentation for Insertional or Noninsertional Achilles Tendinopathy.- Generalities of Insertional Tendinopathy.- Insertional Tendinopathy of the Achilles Tendon.- Endoscopic Techniques.- Achilles Tendon Rupture Generalities.- Conservative Management of Acute Achilles Tendon Rupture.- Open Surgery for Achilles Tendon Ruptures.- Chronic Ruptures of the Achilles Tendon.- Fascial Turn-Down Flap Repair of Chronic Achilles Tendon Rupture.- Peroneus Brevis Tendon Transfer for Chronic Achilles Tendon Ruptures.- Free Gracilis Tendon Transfer for Chronic Rupture of the Achilles Tendon.- Chronic Ruptures of the Achilles Tendon: Management with Synthetic Material.- Management of Complications.- The Achilles Tendon, Ankle Equinus, and Athletes.- Achilles Tendon Involvement in Pediatric Conditions.- Medico-Legal Aspects of Achilles Tendon Disorders.- Genes and the Achilles Tendon.

Tibiofemoral contact mechanics with a femoral resurfacing prosthesis and a non-functional meniscus

BACKGROUND Increased contact stress with a femoral resurfacing prosthesis implanted in the medial femoral condyle and a non-functional meniscus is of concern for potential deleterious effects on tibiofemoral contact mechanics. METHODS Peak contact pressures were determined in seven fresh frozen human cadaveric specimens using a pressure sensitive sensor placed in the medial compartment above the menisci. A knee simulator was used to test each knee in static stance positions (5 degrees/15 degrees/30 degrees/45 degrees) and through 10 dynamic knee flexion cycles (5-45 degrees) with single body weight ground reaction force which was adjusted to the living body weight of the cadaver donor. All specimens were tested in three different conditions: untreated knee (A); flush implantation of a 20mm resurfacing prosthesis (HemiCAP) in the weight bearing area of the medial femoral condyle (B); complete radial tear at the posterior horn of the medial meniscus with the femoral resurfacing device in place (C). FINDINGS On average, flush device implantation resulted in no statistically significant differences when compared to the untreated normal knee. The meniscal tear resulted in a significant increase of the mean maximum peak contact pressures by 63%, 57%, and 57% (all P< or =0.05) at 15 degrees , 30 degrees and 45 degrees static stance positions and 78% (P< or =0.05) through the dynamic knee flexion cycle. No significant different maximum peak contact pressures were observed at 5 degrees stance position. INTERPRETATION Although the condition of a meniscal tear without the resurfacing device could not be compared, possible effects of reduced meniscal tissue and biomechanical integrity of the meniscus must be considered in an in vivo application.

Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants

BackgroundCeramic materials are used in a growing proportion of hip joint prostheses due to their wear resistance and biocompatibility properties. However, ceramics have not been applied successfully in total knee joint endoprostheses to date. One reason for this is that with strict surface quality requirements, there are significant challenges with regard to machining. High-toughness bioceramics can only be machined by grinding and polishing processes. The aim of this study was to develop an automated process chain for the manufacturing of an all-ceramic knee implant.MethodsA five-axis machining process was developed for all-ceramic implant components. These components were used in an investigation of the influence of surface conformity on wear behavior under simplified knee joint motion.ResultsThe implant components showed considerably reduced wear compared to conventional material combinations. Contact area resulting from a variety of component surface shapes, with a variety of levels of surface conformity, greatly influenced wear rate.ConclusionsIt is possible to realize an all-ceramic knee endoprosthesis device, with a precise and affordable manufacturing process. The shape accuracy of the component surfaces, as specified by the design and achieved during the manufacturing process, has a substantial influence on the wear behavior of the prosthesis. This result, if corroborated by results with a greater sample size, is likely to influence the design parameters of such devices.

The influence of a single-radius-design on the knee stability

Prostheses with single radius (SR) design were supposed to be as good as the physiological kinematic and stability of the knee. This in-vitro biomechanical study compared SR to a multiple radius (MR) design on the one hand and seven left human knee specimens were used. The SR and MR knee prosthesis where implanted with a navigation system. We measured varus/valgus deviation of the mechanical axis and the deviation of the joint-line to the epicondyle-line in different knee flexion degrees (0°, 30°, 45°, 60° and 90°) with and without 15 Nm of varus and valgus stress. Without varus/valgus-stress in all three groups (physiological knee, SR and MR prosthesis) the results were located on the varus-site. The variation of the SR was less than the MR, without being significant. Under varus and valgus stress varus/valgus axis deviation constantly grew. From 0-60° no significant deviation between the two prosthesis models was found. At 90° flexion varus/valgus deviation with the SR component was significantly (p ⩽ 0.05) smaller compared to the MR design. This in-vitro study showed that the SR prosthesis is significantly more stable in the coronal plane than the MR in higher flexion degrees. This could have an improved effect on biomechanical stability with a higher clinical function after SR-TKA.

Hallux Rigidus Treatment With Cheilectomy, Extensive Plantar Release, and Additional Microfracture Technique

Cheilectomy is an established method for the treatment of hallux rigidus. In a prospective study, dorsal cheilectomy combined with an extensive plantar release and microfracture technique was performed in 36 patients with 37 cases of hallux rigidus. Patients were rated using the American Orthopaedic Foot & Ankle Society Metatarsophalangeal-Interphalangeal Score and a visual analogue score. Preoperative radiographs showed 25 cases of grade 2 and 12 cases of grade 3. Score results improved significantly from 43 points preoperatively to 78 points (range 35-100 points), both after 1 and 2 years postoperatively. The outcome of the Visual Analogue Score after 2 years was 7.1 for pain (preoperative: 2.2; 1 year: 7.0), 7.1 for function (preoperative: 2.8; 1 year: 6.7), and 7.4 for satisfaction (preoperative: 1.1; 1 year: 6.6). Clinical examination showed an average improvement in range of motion of 22°. Patients classified as grade 3 were found to have poorer results than grade 2. The described technique has proven to be an effective method to relieve pain and improve function. However, longer-term results remain to be evaluated.