Peter E. Ochsner

Non-operative treatment versus tension-band osteosynthesis in three- and four-part proximal humeral fractures : A retrospective study of 34 fractures from two different trauma centers

Summary.Thirty-four patients with three- and four-part proximal humeral fractures from two different trauma centres were studied retrospectively. Sixteen were treated without osteosynthesis and compared with 18 patients treated with tension-band fixation. Fracture classification and clinical examination were made by the same persons in both groups. Most of the three-part fractures healed with good pain relief and good function in daily life but often with a loss of motion. Four-part fractures often led to pain, loss of motion and of function. Conservative treatment seemed superior to tension-band fixation for three-part fractures. Four-part fractures healed with better function and range of motion after tension-band fixation.Résumé.Trente-quatre patients présentant une fracture à trois ou quatre fragments de l’extrémité proximale de l’humerus ont été examinés rétrospectivement. Seize d’entre eux avaient été traités sans ostéosynthèse et comparés avec dix-huit patients stabilisée par haubanage. La classification des fractures ainsi que l’examen clinique des deux groupes ont été effectués par les mêmes personnes. Le plus grand nombre des fractures à trois fragments ont guéri avec une bonne disparition des douleurs, une bonne fonction dans la vie quotidienne mais avec une perte de mobilité. Les fractures à quatre fragments présentent des séquelles fréquentes telles que douleur et perte de fonction et de mobilité. Un traitement non stabilisateur semble supérieur à l’ostéosynthèse par haubanage pour les fractures à trois fragments. Les fractures à quatre fragments ont guéri avec une meilleure fonction et une meilleure mobilité lorsqu’elles ont été traitées par ostéosynthèse.

Chronic complicated osteomyelitis of the appendicular skeleton: Diagnosis with technetium-99m labelled monoclonal antigranulocyte antibody-immunoscintigraphy

Chronic post-traumatic osteomyelitis (OM) represents a particular challenge for nuclear medicine and radiology since clinical and biochemical parameters are frequently unreliable. The aim of this study was to investigate the value of combined bone scan (BS) and immunoscintigraphy (IS) with technetium-99m labelled monoclonal antigranulocyte antibody (MAB) in patients with suspected chronic OM of the appendicular skeleton. Twenty-four patients (17 females and 7 males) with suspected chronic post-traumatic OM were evaluated with three-phase BS/99mTc-MAB-IS. The final diagnosis was established by means of bone culture and histology in 19 cases and clinical follow-up in five cases. The studies were reviewed by two independent and experienced observers; the interobserver agreement was calculated by kappa statistics. The sensitivity, specificity and accuracy of BS alone were 92%, 18% and 58%, respectively. Combined BS/99mTc-MAB-IS. had a sensitivity, specificity and accuracy of 84%, 72% and 79%, respectively. Of 24 studies, 11 were true-positive, two false-negative, eight true-negative and three false-positive. Two patients presented with unexpected ectopic haematopoietic bone marrow in the appendicular skeleton that caused falsepositive results. A high degree of interobserver agreement was found (κ=0.85). It is concluded that combined BS/99mTc-MAB-IS. represents a very sensitive and reproducible method with an acceptable specificity for the investigation of chronic OM. Problems may occur in the differentiation of low-grade OM from aseptic inflammation. Another problem is ectopic marrow that may occur in the appendicular skeleton due to a chronic inflammatory stimulus. A former intramedullary intervention in the femur with displacement of haematopoietic marrow may also lead to an ectopic location.

Der Wert der SL-Revisionsprothese nach Wagner zur Überbrückung großer Femurdefekte

ZusammenfassungDie SL-Revisionsprothese nach Wagner wurde an unserer Klinik zwischen 1988 und 1999 in 99 Fällen eingesetzt. Hauptindikationen waren aseptische oder septische Lockerungen, periprothetische Frakturen bei lockeren Prothesen und Girdlestone-Situationen. In der überwiegenden Zahl bestanden schwere meta- oder metadiaphysäre Defekte; 50 Mehrfachrevisionen standen 49 Erstrevisionen gegenüber.Der Zugang wurde meistens transglutaeal oder transfemoral gewählt. Als Verankerungsstrecke beschränkten wir uns zunehmend auf eine Länge von 8–12 cm. Wird innerhalb der ersten Monate eine saumlose knöcherne Integration erreicht, bleibt diese langfristig erhalten.Wegen starkem Einsinken innerhalb des 1. Jahres mussten 6 Schäfte ersetzt werden. Zusätzlich kam es zu 7 Revisionen wegen Hämatomen und 3 wegen Seromen. Nach der Kaplan-Meier-Kurve blieb bis 10 Jahre postoperativ eine Überlebenswahrscheinlichkeit, bezogen auf den Schaft von 92%. Zwischen dem 5. und 10. Jahr erfolgte keine Revision.Bei der 1-Jahres-Kontrolle beträgt die Schmerzfreiheit 96% wobei 90% der Patienten mit dem Operationsergebnis zufrieden sind. Dennoch zeigen 80% der Patienten ein Hinken und 33% benötigen mindestens einen Stock als Gehhilfe. Vorwiegend auf die Abnahme des Allgemeinzustands ist die Verschlechterung der Gehfähigkeit zwischen der 1- und 5-Jahres-Kontrolle zurückzuführen.Die Resultate des SL-Revisionsschafts unterscheiden sich nicht für kleine oder große femorale Defekte. Wir verwenden den SL-Revisionsschaft heute fast ausschließlich bei ausgedehnten Defekten. Eine sorgfältige Operationsplanung ist unumgänglich.AbstractBetween 1988 and 1999 we used the Wagner SL revision prosthesis in 99 cases. The indications were aseptic and septic loosening, periprosthetic fractures, and Girdlestone situations. These were mostly Paprosky types 2 and 3 meta- and metadiaphyseal femoral bone defects. The intervention was the first revision in 49 cases and the second or up to the sixth revision in 50 cases.A transgluteal or transfemoral approach was usually chosen. We gradually reduced the anchorage area to a length of 8–12 cm. If after the first few postoperative months an osseous integration without radiolucency is achieved, a long-lasting integration can be expected.Due to considerable subsidence during the 1st year, six stems had to be replaced. Seven additional revisions were done because of hematoma and three because of seroma. According to the survival analysis, 92% of the stems remained in place after 10 years. No revision was executed between the 5th and 10th year.At the 1-year control, 96% of the patients were pain free and 90% were satisfied. Nevertheless, 80% limped and 33% used at least one crutch. Mainly because of deterioration of general health, the walking distance was considerably reduced between the 1st and the 5th postoperative year.There is little difference in the results after revision between a relatively small and an extended defect. At present, we limit the use of the SL revision stem mainly to extended defects. Careful planning of the operation is mandatory.

Statistical analysis of failure times in total joint replacement

Time to revision is an important criterion describing the quality of implants in total joint surgery. Estimates of failure probabilities are required to inform a patient about the risk of suffering a reoperation. Also, regression models are used for comparing different prosthesis designs. Typically, patients dying before a revision are considered as censored for time to prosthesis failure. We argue that this technique is inadequate for estimation of failure probabilities and insufficient for comparison of different designs. We propose a new approach based on a competing risk model to account for concurrent mortality. We describe differences in the estimation of failure probabilities and in the interpretation of regression models for implant failure. Additionally, we introduce a random effects term in the regression model to account for potential dependencies in the failure times of bilaterally treated patients. The new approach is illustrated with fictitious data and data from an observational study conducted at a specialized hospital in Switzerland.

Influence of leg length discrepancy on clinical results after total hip arthroplasty - A prospective clinical trial

The effect of leg length differences on early clinical outcome after total hip arthroplasty remains uncertain. We performed a prospective study on 94 patients who were evaluated preoperatively and one year after surgery for clinical leg length differences, which were then compared with radiological measurements. The effect of leg length differences on walking ability, limp, pain and patient satisfaction was studied. The mean clinical leg length difference after operation was 0.05 cm (–1.5 to 1.5, SD 0.5). Clinical and radiological measurements correlated poorly (ω=0.36 pre- and ω=0.186 postoperatively). Patients with a shorter operated leg on clinical assessment were more prone to limping (p<0.05), and patients with a longer leg had more pain compared to patients with equal leg lengths (p<0.05). Walking ability, Harris Hip Score and patient satisfaction were only marginally affected by leg length differences. Virtually equal leg length was achieved for most patients but small differences had a negative influence in relation to limping and pain. Patients should be counselled pre-operatively about possible leg length differences and associated symptoms.

Phenotypic and genotypic characterisation of Staphylococcus aureus causing musculoskeletal infections.

One of the most common pathogens causing musculoskeletal infections remains Staphylococcus aureus. The aim of this multicentre study was to perform a phenotypic and genotypic characterisation of clinical S. aureus isolates recovered from musculoskeletal infections and to investigate differences between isolates cultured from Orthopaedic Implant Related Infections (OIRI) and those from Non-Implant Related Infections (NIRI). OIRI were further differentiated in two groups: Fracture Fixation-Device Infections (FFI) and Prosthetic Joint Infections (PJI). Three-hundred and five S. aureus strains were collected from 4 different Swiss and 2 French hospitals (FFI, n=112; PJI, n=105; NIRI, n=88). NIRI cases were composed of 27 Osteomyelitis (OM), 23 Diabetic Foot Infections (DFI), 27 Soft Tissue Infections (STI) and 11 postoperative Spinal Infections (SI). All isolates were tested for their ability to form biofilm, to produce staphyloxanthin and their haemolytic activity. They were typed by agr (accessory gene regulator) group, spa type and screened by PCR for the presence of genes of the most relevant virulence factors such as MSCRAMMs, Panton Valentine Leukotoxin (PVL), enterotoxins, exotoxins and toxic shock syndrome toxin. Overall, methicillin susceptible S. aureus (MSSA) was more prevalent than methicillin resistant S. aureus (MRSA) in this collection. The OIRI group trended towards a higher incidence of MRSA, gentamicin resistance and haemolysis activity than the NIRI group. Within the OIRI group, PJI isolates were more frequently strong biofilm formers than isolates from the FFI group. A statistically significant difference was observed between OIRI and NIRI isolates for the sdrE gene, the cna gene, the clfA gene and the bbp gene. Certain spa types (t230 and t041) with a specific genetic virulence pattern were only found in isolates cultured from OIRI. In conclusion, our study highlights significant trends regarding the virulence requirements displayed by S. aureus isolates associated with implant related infections in comparison to non-implant related infections. However, future studies including whole genome sequencing will be required to further examine genomic differences among the different infection cases.

Patient and surgery related factors associated with fatigue type polyethylene wear on 49 PCA and DURACON retrievals at autopsy and revision

BackgroundPolyethylene wear is an important factor for longevity of total knee arthroplasty. Proven and suspicious factors causing wear can be grouped as material, patient and surgery related. There are more studies correlating design and/or biomaterial factors to in vivo wear than those to patient and surgery related factors. Many retrieval studies just include revision implants and therefore may not be representative. This study is aimed to correlate patient- and surgery- related factors to visual wear score by minimizing design influence and include both autopsy and revision implants. Comparison between the groups was expected to unmask patient and surgery-related factors responsible for wear.MethodsThe amount of joint side wear on polyethylene retrievals was measured using a modification of an established visual wear score. Fatigue type wear was defined as summation of the most severe wear modes of delamination, pitting and cracks. Analysis of patient and surgery related variables suspicious to cause wear included prospectively sampled patient activity which was measured by self reported walking capacity. Statistical analysis was done by univariate analysis of variance. Activity level and implantation time were merged to an index of use and correlated to the wear score.ResultsWear score after comparable implantation time was significantly less in the autopsy group. Even so, fatigue type wear accounted for 84 and 93 % of total wear score on autopsy and revision implants respectively. A highly significant influence on wear score was found in time of implantation (p = 0.002), level of activity (p = 0.025) and inserts belonging to revision group (p = 0.006). No influence was found for the kind of patella replacement (p = 0.483). Body mass index and accuracy of component alignment had no significant influence on visual wear score. Fatigue-type wear in the medial compartment was closely correlated to the index of use in the autopsy (R2 = 0.383) and the revision group (R2 = 0.813).ConclusionThe present studys finding of substantial fatigue type wear in both autopsy and revision retrievals supports the theory that polyethylene fatigue strength is generally exceeded in this type of prosthesis. Furthermore, this study correlated fatigue-type polyethylene wear to an index of use as calculated by activity over time. Future retrieval studies may use activity over time as an important patient related factor correlated to the visual wear score. When evaluating total knee arthroplasty routine follow up, the surgeon must think of substantial wear present even without major clinical signs.

Excellent long-term results of the Müller acetabular reinforcement ring in primary total hip arthroplasty.

Background and purpose — The original Müller acetabular reinforcement ring (ARR) shows favorable medium-term results for acetabular reconstruction in total hip arthroplasty, where it is used when the acetabular bone stock is deficient. However, there are no data regarding long-term survival of the device. We therefore investigated long-term survival and analyzed radiological modes of failure. Patients and methods — Between 1984 and 2002, 321 consecutive primary arthroplasties using an ARR were performed in 291 patients. The mean follow-up time was 11 (0–25) years, and 24 hips were lost to follow-up. For survival analysis, we investigated 321 hips and the end of the follow-up was the date of revision, date of death, or the last patient contact date with implant still in situ. Radiological assessment was performed for 160 hips with a minimum of 10 years of follow-up and with radiographs of sufficient quality. It included evaluation of osteolysis, migration, and loosening. Results — 12 ARR THAs were revised: 1 isolated ARR revision for aseptic loosening, 4 revisions of the ARR and the stem for aseptic loosening, 6 for infection, and 1 for recurrent dislocation. The cumulative revision rate for all components, for any reason, at 20 years was 15% (95% CI: 10–22), while for the ARR only it was 7% (95% CI: 4–12) for any reason and 3.4% (95% CI: 1–9) for aseptic loosening. 21 (13%) of 160 ARR THAs examined had radiological changes: 7 had osteolysis but were not loose, and 14 were radiologically loose but were not painful and not revised. Interpretation — Our data suggest that the long-term survival of the ARR is excellent.

Eradication of infection, survival, and radiological results of uncemented revision stems in infected total hip arthroplasties

Background and purpose — The use of uncemented revision stems is an established option in 2-stage procedures in patients with periprosthetic joint infection (PJI) after total hip arthroplasty (THA). However, in 1-stage procedures, they are still rarely used. There are still no detailed data on radiological outcome after uncemented 1-stage revisions. We assessed (1) the clinical outcome, including reoperation due to persistent infection and any other reoperation, and (2) the radiological outcome after 1- and 2-stage revision, using an uncemented stem. Patients and methods — Between January 1993 and December 2012, an uncemented revision stem was used in 81 THAs revised for PJI. Patients were treated with 1- or 2-stage procedures according to a well-defined algorithm (1-stage: n = 28; 2-stage: n = 53). All hips had a clinical and radiological follow-up. Outcome parameters were eradication of infection, re-revision of the stem, and radiological changes. Survival was calculated using Kaplan-Meier analysis. Radiographs were analyzed for bone restoration and signs of loosening. The mean clinical follow-up time was 7 (2–15) years. Results — The 7-year infection-free survival was 96% (95% CI: 92–100), 100% for 1-stage revision and 94% for 2-stage revision (95% CI: 87–100) (p = 0.2). The 7-year survival for aseptic loosening of the stem was 97% (95% CI: 93–100), 97% for 1-stage revision (95% CI: 90–100) and 97% for 2-stage revision (95% CI: 92–100) (p = 0.3). No further infection or aseptic loosening occurred later than 7 years postoperatively. The radiographic results were similar for 1- and 2-stage procedures. Interpretation — Surgical management of PJI with stratification to 1- or 2-stage exchange according to a well-defined algorithm combined with antibiotic treatment allows the safe use of uncemented revision stems. Eradication of infection can be achieved in most cases, and medium- and long-term results appear to be comparable to those for revisions for aseptic loosening.

Excellent long-term results of the Müller acetabular reinforcement ring in primary cup revision: A single-center study of 259 cases after a mean of 10 years’ follow-up

Background and purpose — The original Müller acetabular reinforcement ring (ARR) was developed to be used for acetabular revisions with small cavitary and/or segmental defects or poor acetabular bone quality. Long-term data for this device are scarce. We therefore investigated long-term survival and radiographic outcome for revision total hip arthroplasty using the ARR. Patients and methods — Between October 1984 and December 2005, 259 primary acetabular revisions using an ARR were performed in 245 patients (259 hips). The mean follow-up time was 10 (0–27) years; 8 hips were lost to follow-up. The cumulative incidence for revision was calculated using a competing risk model. Radiographic assessment was performed for 90 hips with minimum 10 years’ follow-up. It included evaluation of osteolysis, migration and loosening. Results — 16 ARRs were re-revised: 8 for aseptic loosening, 6 for infection, 1 for suspected infection, and 1 due to malpositioning of the cup. The cumulative re-revision rate for aseptic loosening of the ARR at 20 years was 3.7% (95% CI 1.7–6.8%). Assuming all patients lost to follow-up were revised for aseptic loosening, the re-revision rate at 20 years was 6.9% (95% CI 4.1–11%). The overall re-revision rate of the ARR for any reason at 20 years was 7.0% (95% CI 4.1–11%). 21 (23%) of the 90 radiographically examined ARR had radiographic changes: 12 showed isolated signs of osteolysis but were not loose; 9 were determined loose on follow-up, of which 5 were revised. Interpretation — Our data suggest that the long-term survival and radiographic results of the ARR in primary acetabular revision are excellent.