Reduction of High Hip Dislocation With a Distraction Nail and Arthroplasty (Preliminary Results of a Novel Technique).

A novel distraction technique is described for total hip arthroplasty in symptomatic high hip dislocation (Crowe IV) combining an intramedullary motorized lengthening nail with a pelvic support plate to gradually stretch hip soft tissues (distalization) and performing total hip arthroplasty with the cup in the primary acetabulum. Twelve patients (15 hips) were identified in a retrospective study via chart review. Medical records and radiographs were reviewed for details of the initial case parameters, surgical details, magnitude of distalization, duration of treatment, outcomes, and complications. Followed by an average of 67.4 mm of distalization, nearly anatomical cup placement, and equal leg length were achieved in all patients. During distalization, pain level was low with acceptable range of motion. One unplanned surgery and no complications with long-term sequelae occurred.

[Treatment with fully implantable intramedullary distraction nails for limb lengthening-a paradigm shift]. / Behandlung mit voll implantierbaren Distraktionsmarknägeln zur Extremitätenverlängerung ­ ein Paradigmenwechsel.

More than almost any other implant, fully implantable intramedullary distraction nails have changed corrective and reconstructive bone surgery. Based on the fundamentals of callus distraction, these new apparatus developments with their novel planning strategies and minimally invasive surgical techniques have opened up a wide range of indications and made the treatment reproducible and safe. The prerequisite, however, is that standardized procedures are adhered to, which concern both the preparation for the surgery, the surgery itself and the subsequent distraction treatment. Treatment with fully implantable intramedullary distraction nails should be performed at specialized centers, so that the paradigm shift in corrective and reconstructive limb surgery, which is already recognizable, will open the door for further developments.

[The use of distraction osteogenesis for the reconstruction of bone defects following resection of malignant bone tumours]. / Einsatz der Kallusdistraktion zur Rekonstruktion bei langstreckigen, knöchernen Defekten nach Resektion maligner Knochentumoren.

The reconstruction of extensive bone defects following resection of malignant bone tumours is a challenge and is mainly influenced by tumour-related factors. In defect reconstructions using distraction osteogenesis isotropic, high-quality (new) bone is formed. For the reconstruction of bone defects and secondary limb length discrepancies following tumour resection, predominately three techniques have been described: bone transport, primary shortening and secondary lengthening, as well as "bio-expandable tumour endoprostheses". The use of distraction osteogenesis represents an excellent method for defect reconstruction and treatment of secondary limb length discrepancies following bone tumour resection. Due to the complex anatomical preconditions in tumour patients, a high degree of expertise in distraction osteogenesis (and tumour endoprostheses) is paramount. Therefore, treatment of these patients at highly specialised centres is recommended.

Lower limb alignment in the frontal plane: analysis from long standing radiographs and computer tomography scout views: an experimental study.

OBJECTIVES: A profound knowledge of physiologic lower limb alignment is essential to understand deformities and to plan surgical correction. The gold standard in radiographic assessment is the long standing radiograph with a forward directed patella. The advantage of computed tomography (CT) is that its cutting-edge image technique can visualize the femur condyles. Study purpose was to determine if the CT-scout view has the potential to replace the standing radiograph. MATERIALS AND METHODS: We compared the geometric data obtained from long standing radiograph and CT-scout views both with patella forward position. Furthermore, we developed a method of positioning the lower extremity stable on the CT table, where the femoral condyles became the new orientation criterion. Finally, we evaluated differences in the data ascertainment between the long standing radiograph with patella facing forward and the CT-scout view with the posterior edge of femoral condyles orientated parallel to the radiographic cassette. RESULTS: The geometric data of long standing radiograph and CT-scout views are comparable if the leg is in the same rotational position. We developed a CT positioning jig to adjust the femur condyles parallel to the radiographic cassette. In 80 % of the cases, the deviation was 5° or less. These scout views showed statistically significant differences when compared with data from standing radiograph with a forward centered patella. CONCLUSION: No evidence was found clearly excluding the possibility of an exclusive use of the CT-scout view for the analysis of the leg geometry. However, advantages of the long standing radiograph became obvious.

The reverse planning method for lengthening of the lower limb using a straight intramedullary nail with or without deformity correction. A new method.

OBJECTIVE: Lengthening of the lower limb with or without correction of angular deformity using an intramedullary nail with new correction strategies to restore or maintain a normal mechanical axis and orientation of the joints compared to traditional strategies using external fixation. Postsurgical lengthening will occur along the axis of the straight nail. PLANNING TECHNIQUE: The "reverse planning method" starts with the "ideal" final result of the projected correction and goes back to the preexistent deformity. The mechanical axis of the lower limb as well as the bone and joint orientation to it are well-defined geometrically measured. Technical considerations like the entry point of the nail, the diameter and geometry of the diaphyseal canal, the curvature of the bone, the apex of deformity, the level of osteotomy, and the creation of adequate bone segment size to allow for stable "locking" to the intramedullary nail are accommodated. RESULTS: The reverse planning method was used in the author's center in more than 500 cases of deformity correction and lower extremity lengthening using the Fitbone intramedullary lengthening nail, but the planning and surgical principles are applicable to lengthening and deformity correction with other intramedullary straight devices or for "lengthening over a nail" procedures.

Expandable endoprostheses in malignant bone tumors in children: indications and limitations.

Expandable endoprostheses can be an option after resection of malignant bone tumors of the lower extremity in children and adolescents not only to bridge the resultant surgical defect but also to correct a residual limb length discrepancy. Small intramedullary diameter and short residual bone segments, as well as stress-shielding, are intrinsic technical limitations of fully implantable reconstructive devices. As a consequence, until recently, repeated operative interventions to reconstruct the limb and compensate for subsequent absence of growth within the affected limb were required to compensate for continued growth of the contralateral limb. Innovative expandable endoprosthetic devices are now available to help achieve equal limb length at maturity. One common device is a conventional endoprosthesis that is lengthened using a telescopic module, whereas the "bioexpandable" system lengthens the remaining bone using a lengthening nail as a modular part of the endoprosthesis. Both systems are equipped with motor drives that electromagnetic waves activate transcutaneously. One advantage of the "bioexpandable" endoprosthesis is that with sequential lengthening, the proportion of residual bone shaft to prosthesis length increases, thereby diminishing host bone-endoprosthetic lever arm forces.

The bioexpandable prosthesis: a new perspective after resection of malignant bone tumors in children.

Bone reconstruction after resection of malignant bone tumors of the lower extremity in children and adolescents remains a challenge in limb-sparing surgery. Equal limb length at maturity and good functional outcome are the main goals of these surgeries but often are difficult to achieve. Expandable endoprostheses are available but usually require repeated operative interventions for lengthening. Moreover, as the size of the implant increases, the proportion of the implant relative to the remaining bone increases, generating a biomechanical disadvantage to the limb. The authors describe a new concept combining an endoprosthesis with a fully implantable motorized distraction nail that can be activated in gradual steps to lengthen the remaining bone by callus distraction. New high-quality bone is growing and the proportion of prosthesis length compared with leg length develops in favor of the remaining bone.