Introduction: The prosthetic replacement of the infected knee is conditioned by the bone stock according with the A.O.R.I. We classified the bone defects on the infected knee following the Windsor protocol. When we find ourselves on a situation with T2-3 F2-3 and/or post-infection prosthetic replacements, we use tumoral knee prosthesis (“third prosthesis”).

The main causes of segmentary bone defects at the knee, appear after high energy injuries, tumoral resections and after infected total knee arthroplasties. Nowadays the treatment of these lesions, supposes a challenge to the orthopaedic surgeons due to the difficulty of the bone and soft tissue lesions.

Material and Methods: We present our first 35 cases involving tumoral knee prosthesis replacements after infected conminutive fractures around the knee, infected replacements and infections after tumoral resections.

Initially we used the prosthesis FINN model (BIOMET©) on 11 cases, while we have used the RHK model (BIOMET©) on the remaining 24. We followed the two-stage reimplantation using antibiotic PMMA spacers either manual or preformed depending on the defect’s size. Exposure of the stiff or ankylosed knee can be especially difficult when preoperative flexion is limited, so in these situations we use the Whitesides technique (tibial tubercle osteotomy). We used platelet derivated growth factors (inductors) associated with hydroxiapatite (conductors) with the goal to obtain the best possible osteo-integration.

Results: Our results are satisfying, considering we are confronting severe bone defects with a poor situation of soft tissues around the knee. We have not observed major complications involving the use of the inductors and conductors mentioned above.

Conclusions: We consider the use of tumoral knee prosthesis (“third prosthesis”) a useful technique which allows us to avoid the disability promoted by the knee arthrodesis, obtaining satisfactory results according to the severe lesions observed.

Introduction and Objectives: There are knee prostheses that are specifically designed for the treatment of extreme cases of surgical revision of cases with large bone losses. These are hinged systems that provide greater stability and have a wide range of components to reconstruct bone defects Experience with this type of prosthesis is usually limited, due to the fact that it is used in complex and sporadic cases. Our aim is to review the results obtained with the implant of this prosthesis in our unit.

Materials and Methods: From June 2000 until March 2008 we implanted 10 salvage knee prostheses (5 TKR OSS, 5 TKR FINN). These procedures were carried out in 6 women and 4 men of 33 to 77 years of age. Indications for these procedures were many, with predominance of revision surgery of septic knee, bone tumors and failure of an infected osteosynthesis.

Results: We achieved pain relief in 7 patients: Mean morbidity > 45° in 7 cases. And 90% of the patients were satisfied.

Discussion and Conclusions: Large bone defects are difficult to reconstruct, especially when a joint is affected. Revision surgery is difficult and has poor results. Knee salvage prostheses are capable of providing a stable non-painful knee in severely incapacitated patients. We had few complications and we hope to have more cases and be able to carry out a longer follow-up of the ones we had. We are optimistic and we have named this prosthesis ‘the third knee prosthesis’.

Introduction and Objectives: Septic non-union can present a variety of problems for the surgeon, the most common being loss of bone continuity and persistence of infection. When conventional treatments fail we begin to use new bone tissue engineering techniques. The aim of this study is to present our experience over the last 5 years with 50 cases of infected non-union in which we used BMP-7.

Materials and Methods: Between 2002 and 2007 we used BMP-7 in 50 patients according to the protocol established by Friedlaender in 2001. Each patient was treated with allograft and BMP-7 and the same surgical technique was used in every case. Follow-up exams were carried out every 2 months with different control X-rays, analysis and cultures were performed to assess the evolution of consolidation and the end of infection.

Results: We achieved the desired consolidation in almost 70% of cases with good functionality of the affected limbs and freedom from infection. On the other hand, in 30% of cases we did not achieve expected consolidation and we saw that infection still persisted.

Discussion and Conclusions: The most critical and influential parameters affecting the end-result of treatment of infected non-union with BMP-7 are persistence of infection, poor vascularization, inadequate stabilization, and defective coverage of the subcutaneous tissue adjacent to the non-union focus.