Joachim Singer

Periprosthetic fractures of the femur associated with hip arthroplasty

The nature of the treatment of periprosthetic fractures depends on the localisation, the stability of the prosthesis and the condition of the bone. The Vancouver fracture classification has proved to be of value in determining specific modes of treatment. The current review analyses the different therapeutic options resulting in a concept of fracture-specific treatment. In this report we propose an extended version of this classification in which periprosthetic fractures associated with endoprostheses anchored in the epiphysis or metaphysis, as well as interprosthetic fractures, are taken into consideration.

Hip revision arthroplasty in periprosthetic fractures of vancouver type B2 and B3.

Objectives The purpose of the study was to test the hypothesis that stem revision in Vancouver Type B2 and B3 periprosthetic fractures using a transfemoral surgical approach and a modular, noncemented, tapered and fluted revision stem led to reproducibly good results with respect to fracture healing, stability of the prosthesis stem, dislocation, intraoperative fracture, and clinical outcome. Design Prospective study. Setting Orthopaedic specialized clinic and center for joint replacement. Patients Twenty-two patients with periprosthetic fractures of Vancouver Type B2 and 10 of Type B3 were followed of at least 24 months. Main Outcome Measure Fracture healing, stability of the prosthesis stem, complications, and clinical outcome. Results All fractures healed with a mean time of 14.5 ± 5.2 weeks. No cases of subsidence of the stem were observed and, according to the classification of Engh et al concerning the biologic fixation of the stem, there was bony ingrowth fixation in 28 cases and stable fibrous fixation in four cases. One dislocation occurred and there were no cases of intraoperative fracture. The Harris hip score rose continually after the operations; from a score 3-months postoperatively of 59.2 ± 14.6 points, it rose to 81.6 ± 16.5 points after 24 months. According to the classification of Beals and Tower, all results were rated as excellent. Conclusions The methods described here for stem revision lead to reproducibly good results in the treatment of periprosthetic hip fractures of Vancouver Types B2 and B3. Level of Evidence Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Comparison of a minimally invasive posterior approach and the standard posterior approach for total hip arthroplasty A prospective and comparative study

BackgroundIt is not clear whether total hip arthroplasty performed via a minimally invasive approach leads to less muscle trauma compared to the standard approach.Materials and methodsTo investigate whether a minimally invasive posterior approach for total hip arthroplasty results in lower levels of muscle-derived enzymes and better post-operative clinical results than those obtained with the standard posterolateral approach fifty patients in both groups were compared in a prospective and comparative study. The following parameters were examined: muscle-derived enzymes CPK, CK-MM and myoglobin pre-operatively, 24 and 48 hours post-operatively, CRP and hemoglobin on the third postoperative day, loss of blood, daily pain levels, the rate of recovery (time taken to attain predefined functional parameters), the Oxford Hip Score, the SF-36 score and the WOMAC score pre-operatively and six weeks post-surgery, the position of the implant and the cement coating by post-operative X-ray examination.Results and ConclusionsThe minimally invasive operated patients exhibited a significantly lower loss of blood, significantly less pain at rest and a faster rate of recovery but the clinical chemistry values and the other clinical parameters were comparable.

Behavior of tendons during lower-leg lengthening in dogs using the Ilizarov method.

Twenty-two dogs were provided with a circular fixator. Lengthening of the right lower leg by 2.5 cm was performed on 18 dogs 5 days after tibial osteotomy using a distraction rate of 0.5 mm, twice per day. Nine dogs with leg lengthening and two dogs of the control group without leg lengthening were sacrificed at the end of the distraction phase of 25 days and the remaining dogs after another 25 days. Post mortem, the tendons of the tibialis anterior, extensor digitorum longus, peroneus longus, and the Achilles tendon were taken from the operated-on right side and the left nonoperated-on control side and were analyzed histologically. The control group showed no histologic changes in the tendons of either side nor in those of the unlengthened left side of the operated-on dogs. Thirty-three tendons (41%) of dogs with leg lengthening were seen to have undergone histomorphological changes. An increase of the peritendinous connective tissue was seen, combined with chronic inflammatory cell infiltration in the tendons and/or the epitendinous tissues, edema, tendon fragmentation, necrosis, scarring of the tendons with dystrophic calcification and/or ossification, and broadening of the tenosynovial sheath. Furthermore, signs of histoneogenesis with growth in the tendons were found. Degenerative changes occurred far more often in the tendons of the ventral side of the lower leg and a slight pes equinus was regularly observed in the lengthened extremity. Therefore, pes equinus prevention and physiotherapy are important in the therapeutic use of lower-leg lengthening to minimize possible stress-induced damage of the ventral tendons.

Behavior of blood vessels during lower-leg lengthening Using the Ilizarov method

Using a ring fixator, lengthening of the right lower leg by 2.5 cm at a distraction rate of 2 x 0.5 mm per day was performed in 24 beagle dogs. After a postoperative latency period of 5 days and a distraction phase of 25 days, half the dogs were killed (30-day group). The remaining half were killed after a second interval of 25 days (55-day group). After the experiment, the anterior tibialis artery and vein with their supporting vessels, as well as the lesser saphenous vein of both the lengthened right side and the control side were excised and examined histologically, histomorphometrically, and electron microcopically. No morphologic changes of the vascular walls and no increase of collagenous or elastic fibers could be found. The histomorphometric evaluations showed a significant increase in the number of vasa vasorum in the dogs of both the 30- and 55-day groups. No significant difference in thickness of the vascular wall, tunica media, and adventitia could be observed between the lengthened and the control side in both dog groups. It seems that blood vessels can adapt to continuous tension during callus distraction without suffering structural damage and are the least limiting factor concerning distraction speed, distraction rhythm, and distraction length during callus distraction.

The effect of tibial lengthening using the Ilizarov method on the cartilage and the menisci of the knee joint

In order to investigate possible acute damage to the knee joint cartilage and the menisci during tibial lengthening, sixteen young beagle dogs underwent 30% lengthening of the right tibia of 2.5 cm by callus distraction at a distraction rate of twice 0.5 mm per day. A further four dogs comprised the control group with fixator and osteotomy but without lengthening. After a distraction period of 25 days half the dogs were killed (group A) while the other half (eight dogs with limb lengthening and two dogs without) were killed after a further period of 25 days (group B). At the end of the study, the menisci were removed together with three cartilage‐bone cylinders from both femoral condyles from the weight‐bearing zones as well as from the corresponding tibial condyles. Serial sections from the menisci were stained with haematoxylin and eosin (H&E) and Elastica van Gieson. Sections of the cartilage‐bone cylinders were stained with H&E and safranin‐O. Cartilage thickness was measured and the glycosaminoglycan content of the joint cartilage was determined using microspectrophotometry. None of the histological preparations obtained from the untreated and distracted sides showed any signs of damage to the cartilage or to the menisci. There were no significant differences between cartilage thickness and proteoglycan content of the untreated side and the lengthened side. Thus, tibial lengthening using the Ilizarov method does not appear to cause acute damage to the cartilage of the knee joint or to the menisci.

Time course of osteocalcin, bone-specific alkaline phosphatase, and C-terminal procollagen peptide during callus distraction.

This study involved 15 patients who were undergoing extremity lengthening by callus distraction. Blood samples and radiographs of the callus distraction segment were obtained before surgery, every 2 weeks during the distraction phase, and every 4 weeks between the end of distraction and removal of the fixator. A digital radiograph analysis system was used to determine the radiographic density of the callus distraction segments. In addition, the serum parameters osteocalcin, bone-specific alkaline phosphatase, and C-terminal procollagen peptide (P1CP) were evaluated. The radiographic density was constant during the distraction phase, but increased logarithmically during the consolidation period. Similar kinetics were observed for osteocalcin, with an average coefficient of correlation between these two parameters of 0.66 ± 0.15. P1CP levels rose rapidly after surgery and increased further during the consolidation period. Serum levels of bone-specific alkaline phosphatase were not uniform between patients, and there was no correlation to the kinetics of radiographic density or the other serum parameters. The similarity between radiographic density and osteocalcin kinetics, as well as the rapid postoperative increase in P1CP, imply that further information may be obtained about osteoneogenesis from the study of these two serum parameters.