Aims

Periprosthetic joint infections (PJIs) are rare, but represent a great burden for the patient. In addition, the incidence of methicillin-resistant Staphylococcus aureus (MRSA) is increasing. The aim of this rat experiment was therefore to compare the antibiotics commonly used in the treatment of PJIs caused by MRSA.

Background

For some time, optimized perioperative pathway protocols have been implemented in orthopedic surgery. In our hospital an accelerated clinical pathway has been successfully in effect for several years, focused on safely decreasing patients' length of stay and increasing their function at the time of discharge. The aim of the present project was to evaluate whether a further optimization is even more promising regarding early postoperative outcome parameters.

Introduction: Osteochondral lesions of the talus (OCL III–IV°) need both extensive debridement for revitalisation and osteochondral reconstruction of the joint surface. This can be achieved by autologous cancellous bone-grafting and combination with a cell-free bioresorbable collagen-I/III scaffold. Our first results with this technique are presented.

Methods: 25 patients (13 female, 12 male, mean age 30.9 years) with 26 osteochondral lesions of the talus (OCL III–IV°, 15 right, 11 left, 24 medial, 2 lateral, 1 bilateral case) were treated by minimal-invasive debridement, autologous cancellous bone-grafting and application of a porcine collagen-I/III scaffold (ChondroGide^®) and evaluated prospectively by clinical scoring and MRI. The average follow-up was 23.2 (6–36) months. The mean defect size was 2.0 cm², the mean depth 0.7 cm. 14 defects have had at least one (1–3) operation on the defect before. By the use of a distractor a malleolar osteotomy could be avoided in all cases.

Results: The AOFAS-score increased from 67.4 ± 12.2 to 89.5 ± 7.4 points (p< 0.01, t-test). On a visual 10-point scale pain decreased significantly from 6.2 to 1.7 while subjective ankle function improved from a mean of 4.4 ± 1.9 to 7.2 ±1.5. The results were rated excellent in 10/26 cases (38.4%), good in 14/26 (53.8) and fair in 2/26 (7.8%) cases. MRI follow-ups showed a complete or nearly complete defect filling. In two ankles a second-look arthroscopy unveiled the defects filled completely by a regenerative tissue with a smooth surface and good bonding. Full-core biopsies showed a mixed, mostly fibrocartilagenous tissue.

Conclusion: By combination of cancellous bone-grafting with a cell-free collagen-I/III scaffold typical osteochondral lesions of the talus can be adressed effectively in a minimal-invasive one-step procedure. By utilizing mesenchymal stem cells (MSC) for an autogenous reparation process the use of expensive cultured chondrocytes is not necessary. The results concerning clinical functional improvement, pain reduction and patients’ satisfaction as well as defect filling in MRI are promising.

Introduction: Revitalizing of the necrotic subchondral bone is the therapeutic paradigm in OCL/OD of the talus. Bone-marrow stimulation includes K-wire drilling or open debridement and cancellous bone grafting. Our results presented here are based on retrograde core-drilling and autologous cancellous bone-grafting of the talar dome guided by fluoroscopy and arthroscopy. Performed as a minimal-invasive technique, no additional harvesting site for bone-grafting is necessary.

Methods: 38 patients (16 female, 25 male) with 41 symptomatic focal osteochondral lesions (ICRS I–III°) of the talus (3 bilateral) were treated by fluoroscopicguided retrograde coredrilling and autologous cancellous bone-grafting from the drilling cylinder. The results were evaluated retrospectively by use of the Ogilvie-Harris-Score (OHS), subjective clinical ratings on a visual analogue scale (VAS (0–10 max.)) and MRI. The patient’s mean age was 33.2 (±15.4) years. 27 patients (66%) reported a trauma history (sprain, compression). Most defects were located in the medial talus (36/41), 4 were lateral and 1 central. 34 cases were primary interventions. In 14 cases the growth plate of the distal tibial epiphysis was detectable.

Results: The follow-up was 7–54 months with a mean of 29 (±13) months. The arthroscopic findings according to ICRS classified 12/41 as I°, 22/41 as II° and 7/41 as III° lesions. Preoperatively there were 11 poor, 25 fair, 4 good and 1 excellent ratings in the OHS-score turning into 1/9/13/18 postoperatively. There were 75.6% (31/41) overall good/excellent results. Good or excellent results were predominantly seen in grade I with 91.6% (11/12) and in grade II with 77.3% (17/22), whereas grade III showed success only in 42.8% (3/7). Open growth plates resulted good or excellent results in 85.7% (12/14 cases). First-line treatments showed a markedly better outcome of 82.3% (28/34) of good/ excellent results compared to 42.8% (3/7) of second-line treatments. Gender or trauma history did not influence the score results. Pain intensity on a VAS significantly reduced from 7.5 (±1.5) to 3.7 (±2.6). The subjective functional status on the VAS revealed a remarkable increase from 4.6 (±2.3) to 8.2 (±2.0), (p< 0.01). In MRI controls two patients showed a progression into demarcation (IV°) associated with a fair or poor score result.

Conclusion: Our results indicate that fluoroscopic-guided retrograde core-drilling and autologous cancellous bone grafting is an appropriate operative option for talar OCL in minor grades I + II. Performed as a minimal-invasive technique, the subchondral necrosectomy and combined bone-grafting provide extended revitalization properties for OCL healing. Tending to success rates of only 42% in lesions III°, this technique can not generally be recommended here.

Introduction: Bone-marrow stimulating techniques like microfracturing for focal chondral defects of the knee joint are widespread utilizing mesenchymal stem cells (MSC) for an autogenous reparation process. Microfracturing shows good results for smaller defects up to 2cm² while larger defects tend to an early secondary degeneration. Autologous Matrix Induced Chondrogenesis (AMIC®) combines microfracturing with application of a porcine collagen type-I/III bilayer matrix to host the MSC and to stabilize the blood clot.

Methods: 32 patients (25m, 7f, mean age 37.4y (18–52y)) with 35 focal chondral defects of the knee joint (ICRS III–IV°) of the condyle, trochlea and/or patella were treated by standardized microfracturing and application of a collagen matrix (Geistlich Biomaterials, Wolhusen, Switzerland). The outcome was evaluated prospectively by clinical scores and MRI with a follow-up of 6 to 24 months. The mean defect size was 3.86 cm² (1.0 – 6.8 cm²). 22 patients (68%) had at least one operation (1–8) on the knee before. 9 defects were caused by trauma. All 7 patients with osteochondritis dissecans had an autologous bone grafting. In 5 patients an ACL stabilization was performed simultaneously.

Results: All patients considered their knee as abnormal (ICRS III° (70%)) or severely abnormal (ICRS IV° (30%)) preoperatively according to the ICRS functional status. The Cincinnati-Score improved from 52.9 to 81.1 points while the Lysholm-Score rose from 60.4 to 85.9 points (each p< 0.001). Pain decreased significantly from 6.1 to 2.2 (10=max.) on the visual analogue scale. 4 biopsies (4–21 months) revealed reasonable results with regard to surface formation, filling and integration in the Brittberg score (∅10.25 pts., 12 pts.=max.) The MRI follow-ups showed an adequate filling of the defect, no prolonged effusion occured.

Conclusion: Microfracturing in combination with a collagen matrix (AMIC®) is a minimal invasive, effective technique for the repair of focal cartilage defects of the knee joint. Not using cultured chondrocytes it can be performed cost-effectively as a single-step procedure. Both primary and secondary treatments are possible. The first results concerning clinical functional improvement, pain reduction and patients’ satisfaction as well as defect filling in MRI are promising.