C. Baier

Proximal interphalangeal joint replacement with an unconstrained pyrocarbon prosthesis (Ascension®): a long-term follow-up

There have been limited publications that report long-term outcomes of pyrocarbon implants. This report describes both clinical and radiographic long-term results for patients who have been treated with pyrocarbon proximal interphalangeal implants. Thirteen implants in ten patients are reported for an average follow-up of 8.3 years (range 6.2–9.3). All patients were suffering from degenerative joint disease. Five of the 13 digits were free of pain, the remaining eight digits had mild to moderate pain (visual analogue scale 2–5). The average active range of motion was 58° (SD 19°) at latest examination. X-ray results were unremarkable in six digits with an acceptable position of the prosthesis. However, in seven patients significant radiolucent lines (≥ 1 mm) were observed. Three prostheses demonstrated a migration of the proximal component, and one a subsidence of the distal component. Our study does not support the use of this implant for treatment of osteoarthritis of the finger joint owing to high complication rates and limited range of motion.

The influence of component alignment on patellar kinematics in total knee arthroplasty

Background and purpose — Postoperative anterior knee pain is one of the most frequent complications after total knee arthroplasty (TKA). Changes in patellar kinematics after TKA relative to the preoperative arthritic knee are not well understood. We compared the patellar kinematics preoperatively with the kinematics after ligament-balanced navigated TKA. Patients and methods — We measured patellar tracking before and after ligament-balanced TKA in 40 consecutive patients using computer navigation. Furthermore, the influences of different femoral and tibial component alignment on patellar kinematics were analyzed using generalized linear models. Results — After TKA, the patellae shifted statistically significantly more laterally between 30° and 60°. The lateral tilt increased at 90° of flexion whereas the epicondylar distance decreased between 45° and 75° of flexion. Sagittal component alignment, but not rotational component alignment, had a significant influence on patellar kinematics. Interpretation — There are major differences in patellar kinematics between the preoperative arthritic knee and the knee after TKA. Combined sagittal component alignment in particular appears to have a major effect on patellar kinematics. Surgeons should be especially aware of altering preoperative sagittal alignment until the possible clinical relevance has been investigated.

Comparing navigation-based in vivo knee kinematics pre- and postoperatively between a cruciate-retaining and a cruciate-substituting implant

PurposeIndividual physiological knee kinematics are highly variable in normal knees and are altered following cruciate-substituting (PS) and cruciate-retaining (CR) total knee arthroplasty (TKA). We wanted to know whether knee kinematics are different choosing two different knee designs, CR and PS TKA, during surgery using computer navigation.MethodsFor this purpose, 60 consecutive TKA were randomised, receiving either CR (37 patients) or PS TKA (23 patients). All patients underwent computer navigation, and kinematics were assessed prior to making any cuts or releases and after implantation. Outcome measures were relative rotation between femur and tibia, measured medial and lateral gaps and medial and lateral condylar lift-off.ResultsWe were not able to demonstrate a significant difference in femoral external rotation between either group prior to implantation (7.9° CR vs. 7.4° PS) or after implantation (9.0° CR vs. 11.3° PS), both groups showed femoral roll-back. It significantly increased pre- to postoperatively in PS TKA. In the CR group both gaps increased, the change of the medial gap was significantly attributable to medial release. In the PS group both gaps increased and the change of the medial and of the lateral gap was significant. Condylar lift-off was observed in the CR group during 20° and 60° of flexion.ConclusionThis study did not reveal significant differences in navigation-based knee kinematics between CR and PS implants. Femoral roll-back was observed in both implant designs, but significantly increased pre- to postoperatively in PS TKA. A slight midflexion instability was observed in CR TKA. Intra-operative computer navigation can measure knee kinematics during surgery before and after TKR implantation and may assist surgeons to optimise knee kinematics or identify abnormal knee kinematics that could be corrected with ligament releases to improve the functional result of a TKR, whether it is a CR or PS design. Our intra-operative finding needs to be confirmed using fluoroscopic or radiographic 3D matching after complete recovery from surgery.

Patellofemoraler Schmerz nach primärer Knieendoprothetik

ZusammenfassungDie endoprothetische Versorgung des Kniegelenks ist eine Operation mit hohem Zugewinn an Lebensqualität. Dennoch sind je nach Literaturstelle bis zu 50% Patienten von Schmerzen, Bewegungseinschränkung, Instabilität, Infektion oder anderen Komplikationen betroffen. Insbesondere der patellofemorale Schmerz (PFS) ist eine häufige Komplikation nach primärer Knieendoprothetik und wird je nach Literatur in 1–50% der Fälle angegeben. Insbesondere der erhöhte retropatellare Anpressdruck und eine schlechte Führung der Patella werden für den PFS verantwortlich gemacht, doch die Ursachen sind sehr vielfältig. Diagnostik und Behandlung sind komplex und sollten strukturiert durchgeführt werden. Nach der Basisdiagnostik schlagen die Autoren daher eine Einteilung in eine der 4 Gruppen – 1. Tendinosen, 2. mechanische Probleme, 3. intraartikuläre nichtmechanische Probleme, 4. neurogene psychische Probleme – vor. Durch die Einteilung in diese verschiedenen Gruppen werden eine effiziente spezielle Diagnostik und weitere Therapie ermöglicht.AbstractTotal knee arthroplasty (TKA) is an operation with a high gain in quality of life. However, some patients suffer from pain, limited range of motion, instability, infections or other postoperative complications. Patellofemoral pain (PFP) in particular is a common complication after TKA and is often responsible for revision surgery. In particular increasing and localized contact pressure and patella maltracking are held accountable for patellofemoral pain but the reasons are various. Diagnostics and therapy of patellofemoral pain is not easy to handle and should be treated following a clinical pathway. We suggest that patients with patellofemoral pain should be classified into four groups according to the suspected diagnosis after basic diagnostic measures as 1) tenidinosis, 2) mechanical reasons, 3) intraarticular non-mechanical reasons and 4) neurogenic psychogenic reasons. Efficient application of special diagnostic measures and further therapy is facilitated by this classification.Total knee arthroplasty (TKA) is an operation with a high gain in quality of life. However, some patients suffer from pain, limited range of motion, instability, infections or other postoperative complications. Patellofemoral pain (PFP) in particular is a common complication after TKA and is often responsible for revision surgery. In particular increasing and localized contact pressure and patella maltracking are held accountable for patellofemoral pain but the reasons are various. Diagnostics and therapy of patellofemoral pain is not easy to handle and should be treated following a clinical pathway. We suggest that patients with patellofemoral pain should be classified into four groups according to the suspected diagnosis after basic diagnostic measures as 1) tenidinosis, 2) mechanical reasons, 3) intraarticular non-mechanical reasons and 4) neurogenic psychogenic reasons. Efficient application of special diagnostic measures and further therapy is facilitated by this classification.

The oncofetal gene survivin is re-expressed in osteoarthritis and is required for chondrocyte proliferation in vitro

BackgroundRegulation of cell death and cell division are key processes during chondrogenesis and in cartilage homeostasis and pathology. The oncogene survivin is considered to be critical for the coordination of mitosis and maintenance of cell viability during embryonic development and in cancer, and is not detectable in most adult differentiated tissues and cells. We analyzed survivin expression in osteoarthritic cartilage and its function in primary human chondrocytes in vitro.MethodsSurvivin expression was analyzed by immunoblotting and quantitative real-time PCR. The localization was visualized by immunofluorescence. Survivin functions in vitro were investigated by transfection of a specific siRNA.ResultsSurvivin was expressed in human osteoarthritic cartilage, but was not detectable in macroscopically and microscopically unaffected cartilage of osteoarthritic knee joints. In primary human chondrocyte cultures, survivin was localized to heterogeneous subcellular compartments. Suppression of survivin resulted in inhibition of cell cycle progression and sensitization toward apoptotic stimuli in vitro.ConclusionsThe present study indicates a role for survivin in osteoarthritic cartilage and human chondrocytes. In vitro experiments indicated its involvement in cellular division and viability. Learning more about the functions of survivin in chondrocyte biology might further help toward understanding and modulating the complex processes of cartilage pathology and regeneration.

Bone marrow edema syndrome (BMES)

Bone marrow edema (BME) syndrome represents a pathologic accumulation of interstitial fluid in bone - with a traumatic BME being differentiated from a non-traumatic, often ischemic, and a reactive as well as a mechanical BME. Atraumatic/ischemic BME is inconsistently described as a separate entity or as a reversible preliminary stage of osteonecrosis (ON). However, there is always the risk of transformation of BME into ON and subsequent joint destruction. The most common sites of BME are the hip, knee, and ankle. Magnetic resonance imaging is the diagnostic gold standard. Differential diagnoses of the transient BME as osteonecrosis, osteochondrosis dissecans, and a reflex dystrophy should be considered. Conservative or surgical treatment is considered, depending on the etiology of BME. BME syndrome is generally treated conservatively. Infusion of prostacycline or bisphosphonates is a promising option. Ischemic BME and early stages of ON can be successfully treated by core decompression. A combination of both treatment options may also offer advantages.ZusammenfassungBeim Knochenmarködem (KMÖ) handelt es sich um eine pathologische Vermehrung der interstitiellen Flüssigkeit im Knochen mit unspezifischem Erscheinungsbild im Magnetresonanztomogramm (MRT). Unterschieden werden das traumatische, das atraumatische, oft ischämische, das reaktive und das mechanische KMÖ. Das schmerzhafte KMÖS wird uneinheitlich als eigene Entität oder als reversibles Vorstadium der Osteonekrose (ON) betrachtet. Die Gefahr seines Übergangs in eine ON mit Gelenkdestruktion ist immer gegeben. Am häufigsten sind das Hüft-, Knie- und obere Sprunggelenk betroffen. Diagnostische Methode der Wahl ist das MRT. Je nach Ätiologie ist eine konservative oder operative Therapie zu diskutieren. Das KMÖS wird primär konservativ behandelt. Die Infusion von Prostazyklin oder Bisphosphonaten stellt eine gute Option für viele KMÖ dar. Etabliertes Verfahren ist die sog. „core decompression“. Beim ischämischen KMÖ sowie im Frühstadium einer ON könnte eine Kombination beider Verfahren von Vorteil sein.AbstractBone marrow edema (BME) syndrome represents a pathologic accumulation of interstitial fluid in bone – with a traumatic BME being differentiated from a non-traumatic, often ischemic, and a reactive as well as a mechanical BME. Atraumatic/ischemic BME is inconsistently described as a separate entity or as a reversible preliminary stage of osteonecrosis (ON). However, there is always the risk of transformation of BME into ON and subsequent joint destruction. The most common sites of BME are the hip, knee, and ankle. Magnetic resonance imaging is the diagnostic gold standard. Differential diagnoses of the transient BME as osteonecrosis, osteochondrosis dissecans, and a reflex dystrophy should be considered. Conservative or surgical treatment is considered, depending on the etiology of BME. BME syndrome is generally treated conservatively. Infusion of prostacycline or bisphosphonates is a promising option. Ischemic BME and early stages of ON can be successfully treated by core decompression. A combination of both treatment options may also offer advantages.

Do surgical patellar interventions restore patellar kinematics in fixed-bearing, cruciate-retaining total knee arthroplasty?: An in vitro study

Despite different surgical patellar interventions, the decision how to treat the patella during TKA remains controversial. The purpose of this study was to quantify the effect of different reconstructive patellar interventions on patellar kinematics during TKA using optical computer navigation. We implanted ten navigated TKAs in full body specimens. During passive motion, the effect of different surgical patellar interventions on patellar kinematics was analysed. A contrarily tilt behaviour was observed in the TKA group without patellar intervention compared to the natural knee. Lateral release led to similar tilt values (P < 0.05). All surgical interventions led to a 3 to 5mm medial shift of the patella (P < 0.05). None of the analysed surgical patellar interventions could restore natural patellar kinematics after TKA.

Presence of rotational errors in long leg radiographs after total knee arthroplasty and impact on measured lower limb and component alignment

PurposeRotation of the lower limb in weight bearing long leg radiographs has a great impact on measured component and lower limb alignment parameters. We asked which rotational errors of long leg radiographs are present in a high volume centre and which radiological and clinical consequences arise regarding measured coronal component and lower limb alignment after total knee arthroplasty.MethodsIn 100 long leg radiographs coronal femoral and tibial component alignment and hip knee ankle angle (HKA) were measured. Present rotational errors in long leg radiographs were determined by fibular overlap and its impact on alignment parameters calculated.ResultsA mean internal rotation of 8.1° (9.3 SD) with a range between 36° of internal and 16° of external rotation was found in long leg radiographs. This resulted in mean differences between measurements before and after rotational correction regarding femoral and tibial component alignment and HKA of 0.6–0.8° (range 3.5° valgus and 1.6° varus error). Clinically, 11 out of 100 patients were wrongly assigned to either mal- or well-alignment (neutral mechanical alignment within ±3° varus or valgus).ConclusionSurgeons should be aware of potential rotational errors in long leg radiographs after total knee arthroplasty resulting in wrong measurements. In case of rotational errors, radiographs should be repeated or rotational corrections calculated. For study purposes only radiographs after rotational correction should be accepted.

Is it possible to re-establish pre-operative patellar kinematics using a ligament-balanced technique in total knee arthroplasty? A cadaveric investigation

PurposeSeveral authors emphasise that the appearance of patellar maltracking after total knee arthroplasty (TKA) is caused by rotational malalignment of the femoral and tibial components. Ligament-balanced femoral component rotation was not found to be associated with abnormal postoperative patellar position. We hypothesised that a ligament-balanced technique in TKA has the ability to best re-establish patellar kinematics.MethodsIn ten cadaveric knees TKA was performed assessing femoral rotation in ligament-balanced and different femoral and tibial component rotation alignments. Patellar kinematics after different component rotations were analysed using a commercial computer navigation system.ResultsLigament-balanced femoral rotation showed the best re-establishment of patellar kinematics after TKA compared to the healthy pre-operative knee. In contrast to tibial component rotation, femoral component rotation had a major impact on patellofemoral kinematics.ConclusionsThis investigation suggests that a ligament-balanced technique in TKA is most likely to re-establish natural patellofemoral kinematics. Tibial component rotation did not influence patellar kinematics.

Das Knochenmarködemsyndrom (KMÖS)

Bone marrow edema (BME) syndrome represents a pathologic accumulation of interstitial fluid in bone - with a traumatic BME being differentiated from a non-traumatic, often ischemic, and a reactive as well as a mechanical BME. Atraumatic/ischemic BME is inconsistently described as a separate entity or as a reversible preliminary stage of osteonecrosis (ON). However, there is always the risk of transformation of BME into ON and subsequent joint destruction. The most common sites of BME are the hip, knee, and ankle. Magnetic resonance imaging is the diagnostic gold standard. Differential diagnoses of the transient BME as osteonecrosis, osteochondrosis dissecans, and a reflex dystrophy should be considered. Conservative or surgical treatment is considered, depending on the etiology of BME. BME syndrome is generally treated conservatively. Infusion of prostacycline or bisphosphonates is a promising option. Ischemic BME and early stages of ON can be successfully treated by core decompression. A combination of both treatment options may also offer advantages.ZusammenfassungBeim Knochenmarködem (KMÖ) handelt es sich um eine pathologische Vermehrung der interstitiellen Flüssigkeit im Knochen mit unspezifischem Erscheinungsbild im Magnetresonanztomogramm (MRT). Unterschieden werden das traumatische, das atraumatische, oft ischämische, das reaktive und das mechanische KMÖ. Das schmerzhafte KMÖS wird uneinheitlich als eigene Entität oder als reversibles Vorstadium der Osteonekrose (ON) betrachtet. Die Gefahr seines Übergangs in eine ON mit Gelenkdestruktion ist immer gegeben. Am häufigsten sind das Hüft-, Knie- und obere Sprunggelenk betroffen. Diagnostische Methode der Wahl ist das MRT. Je nach Ätiologie ist eine konservative oder operative Therapie zu diskutieren. Das KMÖS wird primär konservativ behandelt. Die Infusion von Prostazyklin oder Bisphosphonaten stellt eine gute Option für viele KMÖ dar. Etabliertes Verfahren ist die sog. „core decompression“. Beim ischämischen KMÖ sowie im Frühstadium einer ON könnte eine Kombination beider Verfahren von Vorteil sein.AbstractBone marrow edema (BME) syndrome represents a pathologic accumulation of interstitial fluid in bone – with a traumatic BME being differentiated from a non-traumatic, often ischemic, and a reactive as well as a mechanical BME. Atraumatic/ischemic BME is inconsistently described as a separate entity or as a reversible preliminary stage of osteonecrosis (ON). However, there is always the risk of transformation of BME into ON and subsequent joint destruction. The most common sites of BME are the hip, knee, and ankle. Magnetic resonance imaging is the diagnostic gold standard. Differential diagnoses of the transient BME as osteonecrosis, osteochondrosis dissecans, and a reflex dystrophy should be considered. Conservative or surgical treatment is considered, depending on the etiology of BME. BME syndrome is generally treated conservatively. Infusion of prostacycline or bisphosphonates is a promising option. Ischemic BME and early stages of ON can be successfully treated by core decompression. A combination of both treatment options may also offer advantages.