Arthroscopic knee chondroplasty using a bipolar radiofrequency-based device compared to mechanical shaver: results of a prospective, randomized, controlled study.

Both mechanical shavers and radiofrequency-based devices are used to treat symptomatic partial thickness chondral lesions. Controversy exists as to which mode of treatment provides better outcomes. The purpose of this study was to compare clinical results after bipolar radiofrequency-based chondroplasty (RFC) to mechanical shaver debridement (MSD). Patients (n = 60) included in the study presented with knee pain associated with a medial meniscus tear and idiopathic ICRS grade III defect of the medial femoral condyle. Patients who had osteoarthritis, grade II or higher cartilage defects of the tibial joint surface, the lateral compartment, or the femoro-patellar joint, or had previously undergone surgery on the affected knee were excluded. Patients underwent partial meniscectomy; during the procedure, they were randomly assigned to receive bipolar RFC (Paragon, ArthroCare Corporation, Austin, TX) or MSD (Full radius resector LR 4.85 x 12.5 cm), Arthrex, Naples, FL). Postoperatively, the same physiotherapist provided instructions for a daily 2-h home training program consisting of isometric, isotonic, and leg lifting exercises; patients were provided the option of using crutches. Clinical outcomes were assessed using the Tegner score, visual analogue scale (VAS) score, and Knee and Osteoarthritis Outcome Score (KOOS) assessment, which consists of five principal domains including pain, symptoms, function in daily living (ADL), and knee related quality of life (QOL), where a score of 0 indicates extreme symptoms and 100 represents no symptoms. Age and time from injury onset did not differ significantly between the RFC and MSD groups (43 +/- 10 vs. 44 +/- 9 years, P = 0.732; 8 +/- 3 vs. 7 +/- 4 months, P = 0.279). No complications or adverse events were observed. Preoperatively, mean (+/-SD) scores for all KOOS principal domains were <20 and did not differ significantly (P > 0.05) between treatment groups. Postoperatively, the RFC patients returned to activity significantly earlier than MSD patients (17 +/- 7 vs. 22 +/- 6 days, P = 0.002). VAS pain scores at 6 h, 24 h, 6 weeks, and 1 year were significantly (P < 0.001) lower for the RFC group than for the MSD group (4 +/- 2, 2 +/- 0.5, 2 +/- 1, 2 +/- 1 vs. 8 +/- 1, 4 +/- 1, 4 +/- 1, 3 +/- 1, respectively). At 1 year, RFC patients had significantly better Tegner score (4.1 +/- 0.8 vs. 2.8 +/- 0.6, P < 0.001) and KOOS domain scores for pain, symptoms, ADL, QOL, respectively (81.1 +/- 8, vs. 59.4 +/- 12.8; 80.7 +/- 7.5 vs. 59.6 +/- 7.5; 81.5 +/- 6.5 vs. 60.1 +/- 6.9; 80 +/- 10 vs. 61.3 +/- 12.5; P < 0.001) than MSD patients. Significantly fewer RFC patients (2% vs 23%, p = 0.026) reported using NSAIDS for knee pain at 1 year. Patients undergoing radiofrequency-based chondroplasty for ICRS grade III medial femoral condyle chondral lesions in conjunction with partial meniscectomy had significantly better clinical outcomes through 1 year than patients with similar pathology receiving chondral debridement using the mechanical shaver.

Evaluation of cartilage defects with near-infrared spectroscopy (NIR): an ex vivo study.

Damaged cartilage undergoes complex changes in composition, histological structure, and mechanical properties. Near-infrared-spectroscopy (NIR spectroscopy) is an important method to measure changes in composition of complex composites. The present study was aimed at evaluating NIR spectroscopy as a means to quantitate tissue alterations in low grade cartilage defects. Fresh medial femoral condyles from female sheep were collected. Cartilage defects were graded according to the International Cartilage Repair Society (ICRS). Specimens were examined by a NIR spectroscopy device (spectral range of 1100-1700 nm). Absorption spectra were calculated from the reference and measurement spectra. As indicator for cartilage composition the ratio (absorption ratio, AR) of the two main absorption bands in this region was calculated. Mechanical stiffness was measured as Shore A. Water-, glycosaminoglycan-, and collagen content and histological grade (Mankin score) were determined. The NIR absorption in ICRS grade 1 defects (AR=2.1+/-0.1) was significantly higher than in intact cartilage (AR=1.5+/-0.1). ICRS grade 2 specimens tended to a higher NIR absorption. NIR absorption correlated significantly with Mankin score (R=0.896), water content (R=0.845), and mechanical stiffness (R=0.877). Initial cartilage degeneration correlates with changes in NIR absorption, indicating NIR spectroscopy to reflect complex structural changes in degenerated cartilage. The data suggest that NIR spectroscopy could be useful for in situ detection of early cartilage defects.

Biomechanical evaluation of rotator cuff repairs in a sheep model: suture anchors using arthroscopic Mason-Allen stitches compared with transosseous sutures using traditional modified Mason-Allen stitches.

BACKGROUND: The optimal method for rotator cuff repair of the shoulder is not yet known. The aim of this study was to compare the time-dependent biomechanical properties of the traditional open transosseous suture technique and modified Mason-Allen stitches (group 1) versus the double-loaded suture anchors technique and so-called arthroscopic Mason-Allen stitches (group 2) in rotator cuff repair. METHODS: Eighteen adult female sheep were randomized into two groups: in an open approach in which the released infraspinatus tendon was repaired with group 1, and with group 2. Animals were sacrificed at 6, 12, or 26 weeks; shoulders were harvested and magnetic resonance imaging was performed. Eight untreated contralateral shoulders served as controls. Tendons of 16 additional unpaired cadaver shoulder joints of adult female sheep were identically treated for analysis at time zero. In a biomechanical evaluation all specimens were loaded to failure at a constant displacement rate using a standard universal testing machine. The load-to-failure and stiffness of the healed bone-tendon interface were calculated. RESULTS: Magnetic resonance imaging analysis showed cuff integrity in all cases, and no evidence of foreign body reaction to the anchors. Load-to-failure and stiffness data did not indicate any significant difference between the two treatment groups, neither at 6 weeks nor at 12 or 26 weeks. However, at time zero the group 2 had a higher load-to-failure in comparison to the group 1 (P<0.010), but there was no difference for the stiffness (P<0.121). CONCLUSIONS: This in vivo study showed that, postoperatively, the group 2 technique provides superior stability and after healing would gain strength comparable to the group 1 technique.

The surgical technique of autologous chondrocyte transplantation of the talus with use of a periosteal graft. Surgical technique.

BACKGROUND: Despite its highly specialized nature, articular cartilage has a poor reparative capability. Treatment of symptomatic osteochondral defects of the talus has been especially difficult until now. METHODS: We performed autologous chondrocyte transplantation in twelve patients with a focal deep cartilage lesion of the talus. There were seven female and five male patients with a mean age of 29.7 years. The mean size of the lesion was 2.3 cm(2). All patients were studied prospectively. Evaluation was performed with use of the Hannover ankle rating score, the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, a visual analog scale for pain, and magnetic resonance imaging. RESULTS: All patients were available for follow-up at a mean of sixty-three months. There was a significant improvement in the Hannover score, from 40.4 points preoperatively to 85.5 points at the follow-up examination, with seven excellent results, four good results, and one satisfactory result. The AOFAS mean score was 88.4 points compared with 43.5 points preoperatively. Magnetic resonance imaging showed a nearly congruent joint surface in seven patients, discrete irregularities in four, and an incongruent surface in one. The patients who had been involved in competitive sports were able to return to their full activity level. CONCLUSIONS: The promising clinical results of this study suggest that autologous chondrocyte transplantation is an effective and safe way to treat symptomatic osteochondral defects of the talus in appropriately selected patients.

Near-infrared (NIR) spectroscopy. A new method for arthroscopic evaluation of low grade degenerated cartilage lesions. Results of a pilot study.

BACKGROUND: Arthroscopy is a highly sensitive method of evaluating high-grade cartilage lesions but the detection of low-grade lesions is often is unreliable. Objective measurements are required. A novel NIRS (near-infrared-spectroscopy) device for detection of low-grade cartilage defects was evaluated in a preliminary clinical study. METHODS: In 12 patients who had undergone arthroscopy, the cartilage lesions within the medial knee compartment were classified according to the ICRS protocol. With a NIR spectrometer system and an optical probe, similar in design to a hook used for routine arthroscopy, the optical properties of cartilage were measured during arthroscopy. RESULTS: The mean ratio of 2 NIR absorption bands of intact cartilage 3.8 (range 2.3 to 8.7).was significantly lower than that of cartilage with grade 1 lesions (12.8, range 4.8 to 19.6) and grade 2 lesions (13.4, range 10.4 to 15.4).No differences were observed between grade 1 and grade 2 lesions. CONCLUSION: NIRS can be used to distinguish between ICRS grade 1 lesions and healthy cartilage during arthroscopic surgeries. The results of this clinical study demonstrate the potential of NIRS to objectify classical arthroscopic grading systems.

Mechanical behavior of intact and low-grade degenerated cartilage.

Young's modulus, elastic and plastic deformation, mechanical hardness and load at failure were determined for low-grade degenerated hyaline cartilage in a porcine model. Osteochondral plugs from the medial condyle of 30 female pigs were used. Cartilage defects were classified using the International Cartilage Repair Society (ICRS) protocol. Mechanical hardness was measured using a Shore A testing device. Total stiffness and plastic deformation was evaluated in the range 50-200 N using a 5-mm indenter. The load at failure was then determined. ICRS grade I specimens showed significantly lower stiffness than grade 0 specimens. ICRS grade 0 specimen showed no significant plastic deformation within the load range 25-100 N. In degenerated cartilage, plastic deformation started at a significantly lower load (50 N). The Young's modulus at 25 N in ICRS grade 0 specimens (18.8 MPa) was significantly higher than in grade I (11.1 MPa) or grade II (10.5 MPa) specimens. Intact cartilage showed significantly higher tension at failure and mechanical Shore A hardness. Young's modulus and tension at failure showed strong correlation. Cartilage degeneration is associated with a significant loss of elasticity and mechanical stress resistance. Shore hardness measurement is an adequate method for rapid biomechanical evaluation of cartilage specimens.

Karl Fischer titration and coulometry for measurement of water content in small cartilage specimens.

This study evaluated the efficiency of Karl Fischer titration and coulometry for measurement of water content in small intact and defective cartilage specimens. Cartilage from the main weight-bearing zone of the medial condyle of 38 fresh sheep knees was used. Of these, 20 condyles had an intact cartilage, while defects (14 grade I and 4 grade II) were found in the rest. The mechanical hardness was determined as Shore A. Cartilage specimens of approximately 5 mg were analyzed in special devices for moisture measurement and then continuously heated up to 105 degrees C. The actual measurement was performed in an electric cell (coulometry). An electrode was laminated with hygroscopic phosphorus pentoxide. In the electrochemical reaction, H and O are liberated from the electrode. The requirement for electric energy correlates with the amount of water in the specimen. The water content in intact cartilage was 66.9%. Grade I (72.6%) and grade II (77.8%) defects had significantly higher water content. Significantly higher and faster spontaneous evaporation was observed in cartilage defects at room temperature. The water content and spontaneous water evaporation correlated with significantly lower mechanical hardness. The experimental design (combined method of thermogravimetry, Karl Fischer titration, and coulometry) was sufficient for evaluating the water content in small cartilage specimens. It is also possible to measure the temperature-dependent water liberation from cartilage specimens.

Factors affecting the outcome of arthroscopy in medial-compartment osteoarthritis of the knee.

PURPOSE: This study was designed to obtain information on factors affecting the medium-term efficacy of arthroscopy (debridement or microfracturing of chondral defects) in patients with unicompartmental osteoarthritis (OA) of the knee. METHODS: A total of 156 patients (71 men and 85 women; mean age, 51.6 +/- 8.7 years [range, 37 to 69 years]) with isolated Kellgren-Lawrence grade 2 medial-compartment knee OA underwent arthroscopy and were followed up. Patients with patellofemoral or lateral-compartment OA were excluded. The Knee Injury and Osteoarthritis Outcome Score was determined in all patients. The outcome was rated poor if this score was less than 114 points or if further surgery was required. Odds ratios (ORs) were calculated by use of multiple logistic regression adjusted for significantly associated factors. RESULTS: Follow-up was performed in 92.9% of the patients, at a mean of 49.2 +/- 2.1 months (range, 47 to 54 months). The outcome was poor in 104 patients (71.7%). There were no gender differences. Factors significantly associated with a poor outcome were a history of OA for greater than 24 months (OR, 3.6), obesity (OR, 8.8), smoking (OR, 3.1), medial tibial osteophytes (OR, 5.4), medial joint space width on standing radiographs of less than 5 mm (OR, 7.3), absence of effusion (OR, 6.5), absence of synovitis (OR, 6.1), presence of crystal deposits (OR, 4.3), deep tibial cartilage defect (OR, 12.5), and need for subtotal or total meniscectomy (OR, 2.2). Patients with more than 4 of these factors had significantly poorer outcomes. CONCLUSIONS: The medium-term outcome of arthroscopy in unicompartmental OA of the knee is poor in about 71.7% of the cases. In this study the outcome did not depend exclusively on the articular findings. Patient age was not associated with a poor outcome. However, a history of OA for more than 2 years, obesity, smoking, tibial osteophytes, and joint space narrowing of less 5 mm were associated with a poor outcome. Patients with 4 or more of these factors should be managed with treatment other than arthroscopy. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Biomechanical investigation of different internal fixations in medial opening-wedge high tibial osteotomy.

BACKGROUND: The medial opening-wedge osteotomy for treatment of varus gonarthritis has become very popular in recent years. Different implants for internal fixation after the osteotomy have been created. It is still unclear, which principle of internal fixation (angle stable or non-angle-stable plate with or without spacer) has the best biomechanical properties. The aim of this study was to determine the biomechanical properties of different fixation techniques in medial opening-wedge high tibial osteotomy in a porcine bone model. METHODS: A 10-mm high tibial opening-wedge osteotomy was performed and stabilized with plates of similar dimensions but different functional principle (conventional plate, angle stable plate with or without spacer). Biomechanical properties (stiffness, displacement within the osteotomy space and load at failure) were evaluated under axial load. RESULTS: Plates which contain a spacer had a significantly higher stiffness at a load at 1000 N (p < 0.05). This correlates with a significantly reduced deformation within the osteotomy space. The strength at failure was not different between the groups. The use of a spacer in a conventional plate produces fractures of the lateral tibial cortex. In angle stable plates and plates containing spacers, the failure was caused by fractures of the lateral tibia surface, the fibula or by displacement within the tibio-fibular joint. The failure was caused primarily by implant insufficiency in plates without spacers. CONCLUSIONS: In a model with comparable conditions, implants which contain a spacer have superior biomechanical properties. Angle stable plates may prevent fractures of the lateral cortex after opening-wedge osteotomy.