Prospective Single-Arm, Multi-Center Trial of a Patient-Specific Interpositional Knee Implant: Early Clinical Results

Within narrow indication of patients with unicompartmental disease, the iForma device can provide improvement in knee function and reduction in pain, however, with a significant higher risk of early revision compared to traditional arthroplasty. Respecting this limitation it may be an alternative option for arthritic patients with unicompartmental disease who have contraindications to High Tibial Osteotomy or are too young for knee replacement; the iForma device further has the distinct advantage of time and cost saving compared to those procedures

Tissue sparing surgery in knee reconstruction: unicompartmental (UKA), patellofemoral (PFA), UKA + PFA, bi-unicompartmental (Bi-UKA) arthroplasties

Recently mini-invasive joint replacement has become one of the hottest topics in the orthopaedic world. However, these terms have been improperly misunderstood as a “key-hole” surgery where traditional components are implanted with shorter surgical approaches, with few benefits and several possible dangers. Small implants as unicompartmental knee prostheses, patellofemoral prostheses and bi-unicompartmental knee prostheses might represent real less invasive procedures: Tissue sparing surgery, the Italian way to minimally invasive surgery (MIS). According to their experience the authors go through this real tissue sparing surgery not limited only to a small incision, but where the surgeons can respect the physiological joint biomechanics

A rare cause for knee pain: fracture of the femoral component after TKR. A case report

We report the rare case of sudden knee pain due to fracture of the total knee replacement nine years after implantation. Fracture occured because of subsequent osteolysis due to polyethylene wear

Correction of flexible lesser toe deformity. Transfer of the flexor digitorum longus tendon

Realignment and pain relief of toes 2-5 by flexor-to-extensor tendon transfer of the flexor digitorum longus (FDL) muscle. As an isolated procedure in flexible proximal interphalangeal (PIP) joint flexion and/or flexible metatarsophalangeal (MTP) joint extension (hammer toe). In combination with a metatarsal osteotomy or PIP joint arthrodesis in case of flexible MTP joint extension. General medical contraindications to surgical interventions. Stiffness of the PIP or MTP joint. Plantar stab incision in the distal interphalangeal (DIP) flexion crease and tenotomy of the FDL tendon. More proximally transverse incision on the plantar aspect of the proximal phalanx and isolation of the FDL tendon. The tendon is split longitudinally along the raphe and the two limbs are transferred from plantar to the dorsal aspect of the proximal phalanx adjacent to the bone. The crossed limbs are sutured to each other under appropriate tension and corrected position of the toe. Postoperative dressings for 3 weeks in corrected position. Subsequently tape dressing in plantar position for 6-12 weeks. Full weight bearing. A total of 24 toes with flexible PIP and/or MTP joint deformity were treated with a FDL tendon transfer. In 14 toes an isolated procedure was performed, in 10 cases an additional metatarsal osteotomy. Patients with operative treatment of the first ray, revision or reoperation were excluded. Mean follow-up was 8.4 (4-14) months. After 6 weeks 22 toes (92%) showed physiological alignment of the PIP and MTP joint. At the last follow-up, 4 (16%) toes had recurrent or persistent extension deformity of the MTP joint. There were no infections, overcorrections, impaired wound healing or transversal malalignment

Fatigue fracture of the hinge pin in a semi-constrained total knee arthroplasty: a case report

Material failure is a rare complication in total knee arthroplasty (TKA). This case report shows a fatigue fracture of the hinge pin as a consequence of a postoperative persisting valgus deviation in a semi-constrained TKA

Micromotion in cemented rotating platform total knee arthroplasty: cemented tibial stem versus hybrid fixation

Introduction: Improving the longevity and reliability of cemented total knee arthroplasty (TKA) remains a major step to achieve. It is still unclear, whether a cemented tibial stem reduces micromotion of the tibial tray and produces therefore a better initial stability or not. The higher conformity of rotating platform design and the possible rotary forces to the tibial platform may produce higher micromotion when the tibial stem remains cementless ( hybrid fixation). Materials and methods: An in vitro study was performed using the PFC(R) mobile bearing tibial tray (DePuy(R), Warswa, IN, USA) to test the hypothesis that the addition of cement surrounding the tibial stem reduces micromotion of the tibial tray in cemented TKA with mobile bearing design. Ten tibial trays with mobile design were implanted in sawbones with a 3-mm cement mantle beneath the baseplate of the tibial tray and with or without the cemented stem. Tibial trays were loaded additionally in the ventral, lateral, medial and posterior positions with 2,500 N using the Zwick Z010(R) instrumentation and HBM pick up Hottinger Baldwin(R). Results: In this study, a significant increased mean maximum liftoff was found when only cementing the tibial baseplate ( hybrid fixation), compared to the fully cemented tibial tray (P< 0.02). Conclusion: In conclusion, the stem of mobile bearing tibial components should be cemented to provide increased micromotion and earlier loosening

Eversion or subluxation of patella in soft tissue balancing of total knee arthroplasty?

Correct postoperative leg alignment and stability of total knee prosthesis over the full range of movement are critical factors for successful TKA. This is achieved by correct implantation of prothesis and soft tissue handling. However, the surgical approach and how to displace the patella are still controversial. We have carried out a cadaver study looking at the effect of patella eversion or subluxation on limb axis alignment during balancing of the knee in three different standard surgical approaches; subvastus, midvastus, or medial parapatellar. For each approach, five knees were studied. Leg alignment was visualised by the Ci((R)) CT-free DePuy/BrainLAB navigation system. Using a navigation system alignment was determined in the AP axis in both extension and 90 degrees flexion, with the patella everted as well as subluxated. Eversion of the patella gave a more valgus axis reading than subluxation in both extension 0.58 degrees (SD: 0.03, range 0.54 degrees-0.60 degrees) and 90 degrees flexion 0.48 degrees (SD: 0.11, range 0.38 degrees-0.60 degrees). The effect was greatest using the medial paraptellar approach. Surgeons should be aware that everting the patella influences the AT alignment when soft tissue balancing in total knee replacement. (c) 2005 Elsevier B.V. All rights reserved