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Aims The management of periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is challenging. The correct antibiotic management remains elusive due to differences in epidemiology and resistance between countries, and reports in the literature. Before the efficacy of surgical treatment is investigated, it is crucial to analyze the bacterial strains causing PJI, especially for patients in whom no organisms are grown. Methods A review of all revision TKAs which were undertaken between 2006 and 2018 in a tertiary referral centre was performed, including all those meeting the consensus criteria for PJI, in which organisms were identified. Using a cluster analysis, three chronological time periods were created. We then evaluated the antibiotic resistance of the identified bacteria between these three clusters and the effectiveness of our antibiotic regime. Results We identified 129 PJIs with 161 culture identified bacteria in 97 patients. Coagulase-negative staphylococci (CNS) were identified in 46.6% cultures, followed by Staphylococcus aureus in 19.8%. The overall resistance to antibiotics did not increase significantly during the study period (p = 0.454). However, CNS resistance to teicoplanin (p < 0.001), fosfomycin (p = 0.016), and tetracycline (p = 0.014) increased significantly. Vancomycin had an 84.4% overall sensitivity and 100% CNS sensitivity and was the most effective agent. Conclusion Although we were unable to show an overall increase in antibiotic resistance in organisms that cause PJI after TKA during the study period, this was not true for CNS. It is concerning that resistance of CNS to new antibiotics, but not vancomycin, has increased in a little more than a decade. Our findings suggest that referral centres should continuously monitor their bacteriological analyses, as these have significant implications for prophylactic treatment in both primary arthroplasty and revision arthroplasty for PJI. Cite this article: Bone Joint J 2021;103-B(6 Supple A):171–176.

Femoral component malrotation in total knee arthroplasty (TKA) is clinically proven to cause dissatisfaction and impaired function. This study is an attempt to characterize the tibiofemoral kinematics following femoral malrotation in posterior stabilized (PS) TKA. It was hypothesized that internal malrotation would introduce the most pronounced changes. Six fresh-frozen cadaver specimens were mounted in a kinematic rig. Three motion patterns were applied with the native knee and following PS TKA (passive motion, open chain extension, and squatting) while infrared cameras recorded the trajectories of markers attached to femur and tibia. Three different femoral implants were tested: a conventional posterior stabilized component, and adapted components of the same implant with 5° of intrinsic external and internal rotation, respectively. The implantation of the PS TKA resulted in less tibial internal rotation (squat 33–70°, p

Fixed-bearing unicompartmental knee arthroplasty (UKA) closely replicates native knee kinematics. As few studies have assessed kinematics following mobile-bearing (MB) UKA, the current study aimed to investigate whether MB UKA preserves natural knee kinematics. Seven fresh-frozen full-leg cadaver specimens were prepared and mounted in a kinematic rig that allowed all degrees of freedom at the knee. Three motion patterns, passive flexion–extension (0°–110° flexion), open-chain extension (5°–70° flexion) and squatting (30°–100° flexion), were performed pre- and post-implantation of a medial MB UKA and compared in terms of rotational and translational knee joint kinematics in the different anatomical planes, respectively. In terms of frontal plane rotational kinematics, MB UKA specimens were in a more valgus orientation for all motion patterns. In the axial plane, internal rotation of the tibia before and after UKA was consistent, regardless of motion task, with no significant differences. In terms of frontal plane, i.e., inferior–superior, translations, the FMCC was significantly higher in UKA knees in all flexion angles and motor tasks, except in early flexion during passive motion. In terms of axial plane, i.e., anteroposterior (AP), translations, during open-chain activities, the femoral medial condyle center (FMCC) tended to be more posterior following UKA relative to the native knee in mid-flexion and above. AP excursions of the FMCC were small in all tested motions, however. There was substantial AP translation of the femoral lateral condyle center during passive motion before and after UKA, which was significantly different for flexion angles > 38°. Our study data demonstrate that the kinematics of the unloaded knee following MB UKA closely resemble those of the native knee while relative medial overstuffing with UKA will result in the joint being more valgus. However, replacing the conforming and rigidly fixed medial meniscus with a mobile inlay may successfully prevent aberrant posterior translation of the medial femoral compartment during passive motion and squatting motion.

The recently reintroduced bicruciate-retaining Total Knee Arthroplasty (BCR TKA) is an interesting approach in the quest for close replication of knee joint biomechanics and kinematics closer to the native knee. Therefore, this study aimed at providing a detailed biomechanical view on the functional resemblance of BCR TKA to the native knee joint. Seven fresh-frozen full leg cadaver specimens (76 ± 10 year) were mounted in a 6 degrees-of-freedom kinematic rig that applied a dynamic squatting motion knee flexion. Two motion patterns were performed pre- and post-implantation of a fixed bearing BCR TKA: passive flexion–extension and squatting while an infrared camera system tracked the location of reflective markers attached to the tibia and femur. Additionally, specimen laxity was assessed using Lachman tests and varus/valgus stress tests in triplicate. Overall, differences in tibiofemoral kinematics between native knee and BCR TKA were small. Some minor differences appeared under the load of a squat: less internal tibial rotation and some minor paradoxical anterior translation of the medial femoral condyle during mid-flexion. BCR TKA may slightly elevate the joint line. Knee laxity as measured by the Lachman and varus/valgus tests was not significantly influenced by BCR TKA implantation. As both cruciate ligaments are preserved with BCR TKA the unloaded knee closely resembles native knee kinematics including preserving the rollback mechanism. The loss of the conforming anatomy of menisci and tibial cartilage and replacement via a relatively flat polyethylene inlay may account for the loss of tibial internal rotation and the slight paradoxical AP motion of the medial femoral condyle with BCR TKA. This phenomenon reproduces findings made earlier with fixed bearing unicondylar knee arthroplasty.

Impingement of the prominent anterior inferior iliac spine (AIIS) against the femoral neck has recently been described as another type of impingement. The purpose of this study is to provide a distribution of AIIS types using the classification proposed by Hetsroni and thus report on the prevalence of prominent types. A total of 400 patients were included in the study with an average age 27.3 ± 6.9 years (range 18–40). All patients received a whole-body polytrauma computer tomography (CT) scan in the emergency room (ER) upon arrival. The classification of AIIS proposed by Hetsroni et al., which describes three morphological types, was used. Type II and III were grouped as prominent types. The measurements were performed in all three planes by two examiners. Male to female ratio was 71:29. Type I was observed in 367 (91.7%) patients. Type II was observed in 31 (7.8%) patients and type III was observed in 2 (0.5%) patients, unilaterally. Prominent types were much more prevalent in men (10.5%) than in women (2.6%). The CT assessment demonstrated excellent intra- and interreliability (overall: 0.926, I/II: 0.906, III: 1.000). A young population demonstrates a prevalence of a prominent AIIS of 11.5%. Prominent AIIS is more common in men than in women.

Background Elevated serum levels of chromium and cobalt ions in metal-on-metal (MoM) bearing surfaces is a well-known phenomenon in THA. However, few studies have addressed this issue in complex primary and revision knee arthroplasty using a MoM hinged mechanism, and no study, to our knowledge, has investigated knees with MoM hinges in patients without megaprostheses (tumor prostheses). Questions/purposes We analyzed a series of patients who received MoM hinged revision knee prostheses and asked: (1) What are the serum metal ion levels at short-term followup? (2) Is there any correlation between metal ion levels and the Knee Society Score (KSS) at this followup? Methods Between 2013 and 2017, we performed 198 revision knee arthroplasties, of which 32 (17.7%) were performed with a latest-generation MoM hinge knee design. In addition, three complex primary TKAs utilizing the same design were included in this study. The device features a metal-on-polyethylene bearing with a MoM hinge. During that period, our general indications for using a hinge were single-stage and two-stage revision surgeries, revisions with large bone defects, and primary TKA with > 20° mechanical malalignment or collateral ligament insufficiency. Of the 35 patients who received this device, 23 patients (65% of the overall group who received this implant; 11 males, 12 females) were available for followup at a median of 28 months (range, 13-61 months), and the remaining 12 (35%) patients were lost to followup. Our rationale for reporting before the more typical 2-year minimum was the finding of elevated serum ion levels with unclear clinical significance. Median age at the time of surgery was 68 years (range, 52-84 years). None of the patients included in the study had other implants with MoM bearings. Serum ion levels of chromium (III) and cobalt were assessed using mass spectrometry. Ion levels > 5 ppb were considered elevated. Clinical outcome was assessed using the original KSS. Results Median chromium serum level was 6.3 ppb (range, 0.6-31.9 ppb) and median cobalt serum level was 10.5 (range, 1.0-47.5 ppb). Of the 23 patients, 16 had elevated serum ion levels. There was a moderate correlation between KSS and both chromium (p = 0.029, r = 0.445) and cobalt (p = 0.012, r = 0.502) levels. Conclusions Elevated metal ion levels and radiolucent lines are common after surgery with this MoM hinge design at short-term followup, and we believe this finding is of great concern. Although no patient has yet been revised, these patients will be closely monitored. We recommend that serum ion analysis become a routine part of followup after any hinge TKA in an attempt to better understand the potential consequences of this phenomenon. Level of evidence Level IV, therapeutic study.

Balancing mobile-bearing (MB) unicondylar knee arthroplasty (UKA) is challenging. If performed improperly, potential complications include pain, implant loosening, or progression of osteoarthritis in the preserved compartment. The purpose of this study was to document effects of improper balancing on knee kinematics and joint contact stress. It was hypothesized that over-stuffing would lead to more valgus and higher lateral contact force. Seven fresh-frozen cadaver legs were mounted in a kinematic rig that applied three motion patterns to the specimens: passive flexion–extension, open chain extension, and squatting. During testing, an infrared camera system recorded the trajectories of markers rigidly attached to femur and tibia, while a pressure sensor measured contact pressure in the lateral compartment. Prior computer tomography scans allowed identification of coordinate frames of the bones and calculations of anatomical rotations and translations. Collateral ligament strains were calculated, and quadriceps forces recorded. Following testing on the native knee, a medial MB UKA was implanted in each specimen and all motion trials were repeated. Three inlay thicknesses were tested to simulate optimal balancing as well as under- (1 mm thinner) and over-stuffing (1 mm thicker) of the medial compartment relative to the optimal thickness. Under-stuffing of the medial compartment leads to kinematics closest to the native knee. Subjectively balanced and over-stuffed MB UKA knees were in more valgus. Lateral peak contact stress was higher from mid- to deep flexion following UKA in all three tested states; however, these results were not significant. Peak strain in the superficial medial collateral ligament (sMCL) was significantly higher in MB UKA, regardless of the inlay thickness mainly in mid-flexion. Inlay thickness had no significant impact on measured quadriceps force during squatting. The results underline the importance of optimal balancing. Over-stuffing should be avoided as it results in the largest kinematic changes relative to the native condition and induces higher strains in the sMCL. Based on the kinematic findings, it is advisable to use thinner inlays, as long as this is not compromising stability or risking inlay luxation.

Treatment of implant-associated osteomyelitis regularly involves the use of systemic antibiotics in addition to surgical intervention. However, it remains unclear if perioperative systemic application of bactericide substances can improve overall outcome in models of severe intramedullary infection. The present study investigated the use of systemic gentamicin in addition to a controlled local release from a highly lipophilic gentamicinpalmitate compound while the previous study showed efficacy of sole antibiotic implant-coating. Forty male Sprague–Dawley rats were divided into two groups receiving an intramedullary femoral injection of 102 CFU of a common methicillin susceptible Staphylococcus aureus strain (MSSA Rosenbach). Group I received an uncoated implant whereas group II received a coated implant. All animals received a single shot intraperitoneal application of gentamicinsulfate directly after wound closure while the historical control group III (n = 20) had no antibiotic treatment at all. Animals were observed for 28 and 42 days. Serum haptoglobin and relative weight gain were assessed as well as roll over cultures of explanted femur nails and histological scores of periprosthetic infection in dissected femora. Systemic application of gentamicin combined with antibiotic-coated implant did not further reduce bacterial growth significantly compared with systemic or local antibiotic application alone. Combined local and systemic therapy reduced serum haptoglobin significantly after day 7, 28 and 42 whereas systemic application alone did not compare to controls. Systemic perioperative and implant-associated application of antibiotics were both comparably effective to treat implant-associated infections whereas the combined antibiotic therapy further reduced systemic signs of infection time dependent.

Posterior-stabilized (PS) and cruciate-retaining (CR) total knee arthroplasties (TKA) are both successfully used for treatment of end-stage osteoarthritis. The choice of constraint depends on knee deformity and stability as well as most importantly surgeon preference. The aim of this study was to compare the amount of blood loss and required transfusions following TKA with the two different designs. In a retrospective approach, 473 patients undergoing TKA were included (240 CR and 233 PS from a single manufacturer). Demographics at base line were comparable between both groups. Blood loss [red blood cell (RBC) loss] was calculated after documentation of pre- and postoperative hematocrit levels at discharge. Transfusion requirements were recorded. Statistical analysis was done using Mann–Whitney U test. The calculated blood loss (RBC loss) at discharge was 548 ± 216 ml in the PS group compared with 502 ± 186 ml in the CR group (p = 0.032). There were no differences in the transfusion requirements between both groups (PS 0.41 vs. CR 0.37, p = 0.39). The blood loss was significantly higher in the PS group. This may be due to the box preparation that exposes more cancellous femoral bone, which may add to postoperative bleeding. The differences remain, however, small, as they did not lead to a significantly higher transfusion rate with PS TKA.

Implant-associated osteomyelitis still represents a demanding challenge due to unfavourable biological conditions, bacterial properties and incremental resistance to antibiotic treatment. Therefore different bactericide or bacteriostatic implant coatings have been developed recently to control local intramedullary infections. Controlled local release of gentamicin base from a highly lipophilic gentamicin palmitate compound achieves extended intramedullary retention times and thus may improve its bactericide effect. Forty male Sprague-Dawley rats were divided into two groups receiving an intramedullary femoral injection of 102 colony-forming units (CFU) of a common methicillin susceptible Staphylococcus aureus strain (MSSA Rosenbach) and either an uncoated femur nail (Group I) or a nail coated with gentamicin palmitate (Group II). Animals were observed for 28 and 42 days. Serum haptoglobin and relative weight gain were assessed as well as rollover cultures of explanted femur nails and histological scores of periprosthetic infection in dissected femurs. Implants coated with gentamicin palmitate significantly reduced periprosthetic bacterial growth as well as signs of systemic inflammation compared with uncoated implants. Gentamicin palmitate appears to be a viable coating for the prevention of implant-associated infections. These findings will have to be confirmed in larger animal models as well as in clinical trials.

It is assumed that unicondylar knee arthroplasty (UKA) features kinematics close to the natural knee. Clinical studies have also shown functional benefits for UKA. There is to date only little biomechanical data to support or explain these findings. The purpose of this study was to investigate whether UKA is able to preserve natural knee kinematics or not. Six fresh frozen full leg cadaver specimens were prepared to be mounted in a kinematic rig with six degrees of freedom for the knee joint. Three motion patterns were applied before and after medial UKA: passive flexion–extension, open chain extension, and squatting. During the loaded motions, quadriceps and hamstrings muscle forces were applied. Infrared cameras continuously recorded the trajectories of marker frames rigidly attached to femur, tibia, and patella. Prior computer tomography allowed identification of coordinate frames of the bones and calculations of anatomical rotations and translations. Native kinematics was reproduced after UKA in all the specimens. In the unloaded knee and during open chain extension, femoral rollback patterns after UKA were very close to those in the native knee. During squatting, the medial femoral condyle after UKA tended to be more posterior and superior with flexion and there was less tibial internal rotation. The tibia was found to be more in valgus after UKA during all motion patterns. As ligaments, lateral compartment and patellofemoral anatomy are preserved with UKA; the unloaded knee closely resembles native kinematics. The slight kinematic changes that were found under load are probably due to loss of the conforming medial meniscus and to the mismatch in geometry and stiffness introduced by UKA. These patterns resemble those found in knees with significant loss of function of the medial meniscus.

Lumbar facet joint degeneration is a source of chronic low back pain, with an incidence of 15% to 45% among patients with low back pain. Various therapeutic techniques in the treatment of facet-related pain have been described in the literature, including intraarticular lumbar facet joint steroid injections and radiofrequency denervation. In this study, we compared the effectiveness of intraarticular facet joint steroid injections and radiofrequency denervation.Our randomized, double-blind, controlled study included patients who received intraarticular steroid infiltrations in the lumbar facet joints (L3/L4-L5/S1) and patients who underwent radiofrequency denervation of L3/L4-L5/S1 segments. The inclusion criteria were based first on magnetic resonance imaging findings showing hypertrophy of the facet joints L3/L4-L5/S1 and a positive response to an intraarticular test infiltration of the facet joints L3/L4-L5/S1 with local anesthetics. The primary end point was the Roland-Morris Questionnaire. Secondary end points were the visual analog scale and the Oswestry Disability Index. All outcome assessments were performed at baseline and at 6 months.Fifty-six patients were randomized; 24 of 29 patients in the steroid injection group and 26 of 27 patients in the denervation group completed the 6-month follow-up. Pain relief and functional improvement were observed in both groups. There were no significant differences between the 2 groups for the primary end point (95% confidence interval [CI], -3 to 4) and for both secondary end points (95% CI for visual analog scale, -2 to 1; 95% CI for Oswestry Disability Index, -18 to 0).Intraarticular steroid infiltration or radiofrequency denervation appear to be a managing option for chronic function-limiting low back pain of facet origin with favorable short- and midterm results in terms of pain relief and function improvement, but improvements were similar in both groups.

In an earlier paper, it was shown that tailored magnetic resonance imaging (MRI) allows for reproducible analysis of the preserved knee joint structures after patellofemoral replacement (PFR).This pilot study investigates to what degree MRI could produce reliable assessment of the implant-bone interface of femoral and patellar components and rotational alignment following PFR.MRI tailored for reduction of metallic artefacts was performed in seven patients who had undergone PFR. Two independent investigators evaluated the implant-bone interface at femoral and patellar components and the rotational alignment of the femoral component. They also assessed their degree of confidence in evaluation using a five-point scale. The inter-observer reliability was determined.Implant-induced MRI artefact was barely observed and there was no interference with component-bone interface evaluation. There was excellent inter-observer reliability, inter-observer agreement, and confidence for the implant-bone interface at femoral and patellar components and for rotational alignment. The applied score for the interface was found to be reliable.Tailored MRI allows reproducible analysis of the implant-bone interface and of rotational alignment of the femoral component in patients who have had PFR. It might prove helpful in the assessment of painful PFR.

Purpose The aim of this study was to assess the reproducibility of using magnetic resonance imaging (MRI) to analyze the preserved anatomic knee compartments following unicondylar knee arthroplasty (UKA) with zirconium femoral components. It was hypothesized that evaluation of the cartilage, ligaments, meniscus, and tendons would result in a high rate of inter-observer reliability. Scope Ten patients underwent MRI of the knee tailored to reduce metallic artifact following medial UKA with zirconium femoral implants. Cartilage, external meniscus, collateral and cruciate ligaments, the quadriceps and patellar tendons, and the presence of joint effusion were evaluated by two independent investigators. The reviewers provided degrees of confidence with their evaluation of each parameter through the use of a five-point scale. Inter-observer agreement was calculated and inter-observer reliability was determined by use of Cohen's Kappa. Artifacts originating from the implants were rarely observed. There was excellent inter-observer reliability (i.e., high Cohen's Kappa) for all assessed structures, and a high level of observer confidence for the evaluation of the cartilage, meniscus, tendons, ligaments, and joint effusion. Conclusion In this study tailored MRI allows for reproducible analysis of the preserved knee joint compartment after UKA for zirconium implants. This technique might prove helpful in the assessment of painful knee joints after UKA with other metallic materials as new MRI software programs, which suppress metal artifacts, are developed.

Introduction No evidence-based guidelines are available to determine the appropriate stem length, and whether or not to cement stems in revision total knee arthroplasty (TKA). Therefore, the objective of this study was to compare stresses and relative movement of cemented and uncemented stems of different lengths using a finite element analysis. Materials and methods A finite element model was created for a synthetic tibia. Two stem lengths (95 and 160 mm) and two types of fixation (cemented or press fit) of a hinged TKA were examined. The average compressive stress distribution in different regions of interest, as well as implant micromotions, was determined and compared during lunge and squat motor tasks. Results Both long and short stems in revision TKA lead to high stresses, primarily in the region around the stem tip. The presence of cement reduces the stresses in the bone in every region along the stem. Short stem configurations are less affected by the presence of cement than the long stem configuration. Press-fit stems showed higher micromotions compared to cemented stems. Conclusions Lowest stresses and micromotion were found for long cemented stems. Cementless stems showed more micromotion and increased stress levels especially at the level of the stem tip, which may explain the clinical phenomenon of stem-end pain following revision knee arthroplasty. These findings will help the surgeon with optimal individual implant choice. ispartof: Archives of Orthopaedic and Trauma Surgery vol:136 issue:12 pages:1741-1752 ispartof: location:Germany status: published

Aim Two different measurement techniques of ultrasonograms of the infant hip were evaluated with respect to reproducibility of the Graf classification and variation of α- and β-angles. Material and methods In a cross-sectional, blinded study, the hips of 207 consecutive newborn babies (101 male; 106 female) were sonographically screened at an average of 2.64 days after birth. Each hip was measured twice by three investigators with different levels of experience - a paediatric orthopaedic surgeon, a senior surgeon and a trained medical student. A mobile ultrasound system (SONOLINE G60S®, Siemens, Erlangen, Germany), equipped with a 7.5 MHz linear transducer, was used. Both hip joints were measured twice by all three investigators. The measurement was performed 6-8 weeks later in a blinded manner. The sonograms were initially printed out on high-quality paper strips and measured by pencil, ruler and goniometer. Finally, each investigator evaluated the same sonograms computer-assisted, using the trackball and dashboard of the ultrasound system. Results Concerning intraobserver reliability, we observed a significant reduction of variation both for α- and β-angles in favour of the classic measurement on printed strips (p 0.05). Conclusions This study demonstrated considerable advantages for the classic measurement of paediatric hip ultrasonograms with pencil and goniometer on printed paper strips compared to computer-aided measurement concerning variation of α- and β-angles.

Several operative techniques have been described for recurrent patellar dislocation. Clinical results vary depending on the procedure and indication. The present study aimed to evaluate the clinical outcome of Insall’s proximal realignment for recurrent patellar dislocation at mid-term follow-up. Forty-five patients were reviewed with a mean follow-up period of 49 months after having undergone Insall’s procedure. Outcome measures included reports of redislocations, complications, patient-reported outcome scores (Kujala, Tegner activity scale) and subjective assessment. No statistically significant improvements (p < 0.05) in patient-reported outcome measures were noted. Sixteen patients (35%) had poor to fair results using the Kujala score. Subjective assessment revealed that 12 patients (27%) were dissatisfied with the outcome of their surgery and would not undergo the same procedure. Ten patients (22%) had suffered from redislocation at the latest follow-up. In 4 cases (9%), intra-articular knee hematoma occurred which required arthroscopic intervention. The overall mid-term outcome of the present study shows low patient satisfaction. Non-anatomic realignment for recurrent patellar dislocation does not adequately prevent redislocation.

The affect of anterior cruciate ligament (ACL) integrity on the early postoperative stability of a collagen type-I gel scaffold was investigated. The value of fibrin glue for graft fixation in ACL deficient porcine knees over a simulated early postoperative period was also studied.Full-thickness articular cartilage defects (11 × 6 mm) were created on the medial femoral condyle of 80 porcine knees. The ACL was left intact or completely transected in each of 40 knees. Gel plugs were tested in each group: press-fitting only in 20 specimens and press-fitting plus fibrin glue in 20 specimens. Each knee underwent 2,000 cycles in a validated ex-vivo continuous passive motion model.Press-fit-only fixation grafts in knee specimens with an intact ACL showed significantly superior stability than that in ACL deficient knees (p = 0.01). In ACL deficient knees, grafts fixed with press-fitting plus fibrin glue showed significantly superior stability than those using press-fit only fixation (p = 0.01). Press-fitting plus fibrin glue fixation showed no significant differences in worn surface area between knee specimens with intact and deficient ACL.ACL deficiency led to early scaffold instability in an ex-vivo porcine knee model. Fibrin glue in ACL deficient knees led to additional graft stability. These findings indicated that cartilage regenerative techniques may give optimum results in ACL intact knees.

Purpose Several well-described techniques are available for the treatment of chondral and osteochondral defects. The aim of the study was to assess the efficacy of a singlestage procedure incorporating a new cell-free collagen type I gel for the treatment of small chondral and osteochondral defects in the knee evaluated at 2-year follow-up. Methods Fifteen patients were treated with a cell-free collagen type I gel matrix of 11 mm diameter. The grafts were implanted in the debrided cartilage defect and fixed by press-fit only. The clinical outcome was assessed preoperatively and at 6 weeks, and 6, 12 and 24 months after surgery using the International Knee Documentation Committee (IKDC) score, Tegner activity scale and visual analogue scale (VAS). Graft attachment rate was assessed 6 weeks postoperatively using magnetic resonance imaging (MRI). Cartilage regeneration was evaluated using the Magnetic Observation of Cartilage Repair Tissue (MOCART) score at 6, 12 and 24 months after implantation. Clinical results were correlated with MRI findings. Results Six male and nine female patients were included in this study, with a mean age of 26 (range: 19‐40). No complications were reported. The mean VAS values after 6 weeks and the mean IKDC patient values after 6 months were significantly improved from the preoperative values (P = 0.005 and P = 0.009, respectively). This improvement remained up to the latest follow-up. There were no significant differences between the median preoperative and postoperative Tegner values (n.s.). Significant improvement of the mean MOCART score was observed after 12 months and remained by 24 months (P \ 0.001). MR images showed that in 14 of the 15 patients, the graft was completely attached by 6 weeks postoperatively. At 24 months after implantation, MRI demonstrated complete filling in all cases with a mainly smooth surface, complete integration of the border zone, homogenous structure of the repaired tissue and nearly normal signal intensity. No correlation between any variables of the MOCART score and the clinical scores was observed. Conclusions The present study reveals that the new method produces both good clinical and magnetic resonance imaging results. Use of press-fit only implanted grafts of a smaller diameter leads to a high attachment rate at 24-month follow-up. Level of evidence IV.

Meniscal loss is associated with an increased risk of developing osteoarthritis. Tissue engineering solutions, which include the development of novel material scaffolds, are being utilised to aid the regeneration of meniscal tissue. The purpose of this study was to monitor the safety profile and the short-term efficacy of a novel polyurethane meniscal scaffold in the treatment of patients with painful knees following partial medial meniscectomy. Ten consecutive patients with segmental tissue loss from the medial meniscus were treated with the arthroscopic implantation of an Actifit® (Orteq Sports Medicine) polyurethane meniscal scaffold. Patients were followed up at 2 and 6 weeks, then again at 6 and 12 months. Primary outcome measures included reporting of complications and patient-reported outcome scores (KOOS, KSS, UCLA Activity scale, VAS pain). Secondary outcome was MRI assessment at 6 and 12 months looking at scaffold morphology, integration and associated joint injury/inflammation. Eight male and 2 female patients were included in the study with a mean age of 29 (range 18–45). No complications were reported. All patients were happy with their surgery. At 6 months, a statistically significant improvement (P

The theoretical superiority of mobile-bearing total knee arthroplasties (TKAs) has not yet been proven in clinical studies. The aim of the current study was to compare and to analyse in a patient population that had received either a fixed or a mobile TKA differences in gait analysis electromyography and clinical scores.In a prospective, randomized, patient- and observer-blinded clinical study, 33 patients with primary osteoarthritis of the knee were included. All patients received a Genesis II total knee replacement. Sixteen patients received a mobile and 17 a fixed-bearing cruciate retaining Genesis II TKA. Clinical and quality-of-life scores, electromyography and gait analysis were applied preoperatively and postoperatively with a follow-up of 24 months.In both groups, improvements from pre- to postoperative were detected. whereas the results of gait analysis and electromyography did not show any differences. The results from the clinical and the quality-of-life scores improved from pre- to postoperative, while the Knee Society Score showed a superiority of the mobile-bearing group (mean 159 ± 28) over the fixed-bearing group (mean 134 ± 41).No functional advantage of mobile over fixed-bearing TKA was detected, although the mobile-bearing group had better clinical results for which a reason could not be found. These results only apply to cruciate retaining mobile-bearing TKA with a bearing which allows both rotation and anteroposterior translation.

STUDY DESIGN A case report to describe the first case of an acute central canal dilatation after minimally invasive lateral cervical decompression. OBJECTIVE To emphasize the need of being aware of this rare spinal disorder. SUMMARY OF BACKGROUND INFORMATION A holocord syrinx is known as a complication of Chiari malformation. Furthermore, it can occur spontaneously, after trauma or infection. METHODS A 63-year-old patient with a left-sided nerve root stenosis, C3/C4, because of uncovertebral and intervertebral joint osteoarthritis with paresis of the left deltoid muscle, underwent minimally invasive decompression of the C4 nerve root according to the Frykholm approach. RESULTS An immediately postoperative recognizably complete paresis of the right arm was because of hydromyelia from the fourth ventricle down to the thoracic spine. A minimal edema of the spinal cord was present. No abnormality of the spinal cord had been detected on preoperative magnetic resonance imaginary (MRI).At revision surgery high pressure was found within the hydromyelia. Subarachnoid drainage did not improve the neurologic deficits. On account of increasing edema of the spinal cord paraplegia developed, which almost completely resolved after further revision. CONCLUSION The reason for the hydromyelia is unclear. Routinely used MRI is not able to detect a collapsed central canal of the spinal cord. Acute hydromyelia causes permanent neurologic deficits whereas edema might lead to transient disturbances.

Grice-Green extra-articular subtalar arthrodesis is a treatment option for advanced valgus rearfoot deformity of neuromuscular origin in young patients. The purpose of this study was to evaluate long-term results of the procedure in ambulatory cerebral palsy patients. From January 1975 to December 1993, 57 operations were performed in 39 patients (22 males, 17 females) with a mean age of 7.8 ± 2.7 (range 3.9–14.4) years for excessive symptomatic hindfoot valgus. Thirty-five patients (51 feet) were followed for a mean 22.6 ± 4.6 (range 16.0–32.3) years. Preoperative GMFCS score, ambulation, hindfoot position, podoscopic view of the weight-bearing feet, and radiological examinations, along with complications and orthotic use, were compared. Based on a clinical rating scale, 39 results were excellent or good, 8 were fair, and 4 were poor. The poor results were attributed to hindfoot valgus recurrence or varus overcorrection. One case needed revisional surgery owing to slippage of the graft. Overall, the GMFCS score, level of ambulatory distance, and use of foot orthoses improved. Grice-Green subtalar arthrodesis did not result in early degenerative changes at the midterm follow-up. The procedure offers safe and long-lasting correction for severe and symptomatic hindfoot disorders in patients with cerebral palsy. Together with physiotherapy and orthotic use, it can improve ambulation. Whereas a slight hindfoot valgus in patients with cerebral palsy is tolerable without lack of function, overcorrection should be avoided.

Unicompartmental knee arthroplasty (UKA) has been proven to be a viable procedure in case of medial osteoarthritis of the knee joint. Minimally invasive surgery (MIS) techniques have been described to facilitate recovery after surgery. The aim of this study was to rule out major failure mechanisms and to obtain clinical data for comparison between a conventional and the MIS approach.A consecutive series of 163 UKA (160 patients) were retrospectively included (83 conventional and 80 MIS interventions). Patients were invited for a clinical examination including clinical scores (KSS, Lequesne, UCLA, VAS, Feller- and Turba Patella Scores). Seven patients (4.3%) were lost to follow-up.Average follow-up was 4.6 ± 1.3 (1.5-6.8) years. Average age at operation was 67.5 ± 7.9 (45-81) years. Fifteen implants had been converted to TKA (9.2%). There were seven conversions to TKA in the MIS and 8 in the conventional group. Of the applied clinical scores there were better values for the Turba patella score in the MIS group. Differences of the other scores were not statistically significant.Comparable functional results for both UKA procedures could be shown. There were no significant differences in terms of clinical scores or revision rates. The MIS approach in medial UKA did not show any major complications. Its use seems to be safe.

Safety and efficacy of unicompartmental knee arthroplasty (UKA) in unicompartmental osteoarthritis (OA) has been shown in large patient series. It has been matter of discussion whether or not spontaneous osteonecrosis of the knee (SONK) can successfully be treated with UKA. A retrospective approach included 52 cases of UKA for SONK of the femoral condyles. Four implants were revised (7.7%), and seven patients had died. Nine patients were interviewed by telephone, 28 followed the invitation for clinical examination including clinical scores (KSS and WOMAC) and radiographs. Satisfaction of patients was recorded in four categories. Four patients (7.7%) were lost to follow-up. Average follow-up was 10.9 ± 4.8 years (4–25). Average age at operation was 66.6 ± 9.7 years. The KSS score increased from a preoperative 85 ± 30 to 173 ± 27 (p

AIM The aim of the study was to survey the current state of the conservative and operative treatment of anterior shoulder instability and its rehabilitation in German hospitals. METHODS A previously evaluated online questionnaire was sent out to all German hospitals with orthopaedic or trauma surgery departments. The Federal Statistical Office's hospital list was the basis for the selection of hospitals. The questions referred to the year 2007. The survey, including 3 reminders, was conducted over 3 months. The questionnaire consisted of 6 response categories: always (100%), almost always (99-81%), predominantly (80-51%), rarely (50-21%), almost never (20-1%) and never (0%). RESULTS The response rate was 41% and 67% of these had carried out shoulder stabilisations. In total, 99.2% of the 67% were evaluable. The proportion of shoulder surgery was 8.4% of the total number of operations. Shoulder stabilisations represented 10.6% of these operations. A specialised shoulder department existed in 22.9%. Conservative treatment was carried out with an immobilisation of the arm "predominantly", "almost always" and "always" for internal rotation in 70.8% and in 23.4% for external rotation. The shoulders were "predominantly", "almost always" and "always" stabilised in an arthroscopic technique in 68.2% and in an open one in 31.8% of the clinics. With 92.9%, the Bankart repair was the most common operation. Shoulder instability was principally treated with the arthroscopic technique, regardless of the care level and department and is considered the best surgical technique. Physiotherapy was prescribed "always" and "almost always" in 99.3%. The rate of reluxation after conservative treatment was estimated at 35.5%, after operative open anterior shoulder stabilisation at 9.1% and after arthroscopic shoulder stabilization at 10.6%. Nevertheless, 49.4% of respondents expected the best results after arthroscopic treatment. Participants, who mainly applied the arthroscopic technique, expected a lower rate of reluxation in comparison to other techniques (p

PURPOSE Every day several million people are seeking for answers to medical problems via the internet. In particular parents, whose children are affected by systemic diseases, orthopaedic defective positions, anomalies or deformities, use the internet to increase their knowledge. Concerning this situation there is a lack of studies in the current literature. METHODS We investigated parental preparation to the outpatient paediatric orthopaedic consultation at our University Hospital with respect to internet enquiries or further sources of information using a standardised questionnaire. We assessed age and educational background of the parents, local hardware equipment and general habits of internet use. In particular, we retrieved parental use of search machines (e.g., Google.de, Yahoo.de), general medical websites (e.g., netdoktor.de) and websites from self-help groups (e.g., klumpfusskinder.de). RESULTS In total, 288 out of 300 questionnaires (96%) were evaluated. More than half of the parents (57%) were over 35 years of age and 78% were women. 82% of the study population had access to the internet at home and 70% used the internet regularly. More than 80% obtained information about the orthopaedic diseases of their child beforehand. Age and educational background of the parents were not significantly correlated with the extent of enquiries (p > 0.05). 90% of the parents, using the internet as source of information, frequented internet search machines; approximately one third used general medical websites. In particular in clubfeet we observed a highly significant (p < 0.001) tendency of parents to frequent websites from self-help groups. 60% of the study population assessed the internet information as useful; 92% will frequent the internet as source of information again. One third of the respondents is going to discuss the obtained internet information with the physician. CONCLUSIONS The internet is an important source of information for parents in the field of paediatric orthopaedics. Treating physicians will be increasingly confronted with the results of parental internet enquiries.

When highly conforming polyethylene inlays were introduced into total knee arthroplasty (TKA), they were characterized as adding anteroposterior stability to the reconstructed knee. The aim of this study was to examine the patellofemoral pressure with the designs of a highly conforming and a posterior stabilized inlay. The patellofemoral pressure depends among other factors on the anteroposterior stability of the knee joint.Eight fresh frozen human knee specimens underwent testing in a kinematic device. Knee motion was driven by a hydraulic cylinder at an extension moment of 31 Nm. The patellofemoral contact pressure was measured using a pressure sensitive film (Tekscan((R)), Inc., Boston, USA). First, this was assessed after implantation of a cruciate retaining (CR) TKA with a highly conforming polyethylene insert before and after resection of the posterior cruciate ligament. After that, the same measurements were performed with a similar posterior stabilized prosthesis.Patellofemoral contact pressures in the CR prosthesis using the highly conforming inlay were not significantly different before and after resection of the posterior cruciate ligament. However, after implantation of a posterior stabilized prosthesis peak pressure was significantly lower [Mean: 6.12, (SD 2.37) MPa] in comparison to the highly conforming type [7.12, (SD 2.53) MPa, P0.01] at a preserved posterior cruciate ligament. Further to that, the mean contact pressure turned out to be lower with the posterior stabilized design (P0.006).The results of this study suggest that a posterior stabilized prosthesis design reduces the patellofemoral peak and mean pressure in comparison with a high conforming design. The better reproducible femoral rollback with a posterior stabilized model at a tibial ventral shift could serve as a possible explanation.

Decreased quadriceps strength and fatigue is suspected to be one of the contributing factors for anterior knee pain and malfunction after total knee arthroplasty (TKA). The purpose of this in vitro study was to investigate the amount of quadriceps force required to extend the knee isokinetically after TKA in dependence of different prosthesis designs and the state of the posterior cruciate ligament (PCL). Eight fresh frozen human knee specimens underwent testing in a kinematic device simulating an isokinetic knee extension cycle from 120° of flexion to full extension. The quadriceps force was measured after implantation of a cruciate retaining (CR) TKA (Genesis II, Smith&Nephew, Memphis, TN, USA) applying a conventional CR (11 mm) and a highly conforming (deep dished, DD) polyethylene (PE) inlay consecutively before and after resection of the PCL. Finally, tests were repeated with a posterior-stabilized (PS) design. Simulating a physiological knee extension, no significant differences in the average quadriceps force were detected between the cruciate preserving inlays (CR 1,146.57 ± 88.04 N, DD 1,150.19 ± 97.54 N, P = 0.86) as long as the PCL was intact. After resection of the PCL, the required quadriceps force increased significantly for both designs (CR 1,203.17 ± 91.51 N, P

AIM The aim of this study was to evaluate the current situation of rotator cuff repair and follow-up treatment in German hospitals. METHODS An evaluated survey, enquiring about the year 2006, was sent to all 777 German orthopaedic and/or trauma surgery departments. The hospitals were chosen using the official index of hospitals from the German Federal Statistical Office. RESULTS 44 % of the surveys were sent back, whereby 40 % were of use. Within the 309 departments, 26 % of the total number of 59,957 shoulder operations were rotator cuff repairs. Mini-open was the operation method in 49 %, open in 29 % and arthroscopic in 22 % of cases. Regarding the operational methods, there were differences between the departments and level of care. The arthroscopic technique was used sometimes in 48 % of the departments, whereas 52 % never used it. Specialised shoulder departments employed the total arthroscopic procedure more often. A set follow-up treatment occurred in 79 % of departments. CONCLUSION Rotator cuff repair is mainly carried out using the mini-open method, which is nowadays regarded as gold standard.

Ziel der Untersuchung war die Erhebung der diagnostischen Wertigkeit der in der Praxis haufig durchgefuhrten klinischen Funktionstests zur Diagnostik des Impingementsyndroms der Schulter. Es erfolgte eine systematische Literaturanalyse fur den Zeitraum von 1978 bis 2008 uber die PubMed-Datenbank. Nach vollstandiger Erfassung aller fur die Arbeit relevanten Artikel wurde die Qualitat der gefundenen Literatur bewertet und die Daten aus jedem Artikel analysiert. Die Qualitatsbeurteilung erfolgte unter Anwendung des Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS), das zur Einschatzung der internen und externen Validitat der einzelnen Studien diente. Insgesamt wurden elf Artikel aus der Literaturrecherche in die Datenerhebung mit eingeschlossen. Die ausgewahlte Literatur zeigte ein inhomogenes Datenmaterial mit zum Teil geringer Studienqualitat. Eine Vielzahl der klinischen Funktionstests wird fur unterschiedliche Pathologien verwendet. Die ausgewahlten Studien zeigen eine statistische Inhomogenitat, die sich durch verschiedene Kriterien ergibt. Die Einschlusskriterien der Patienten in den Studien sind unterschiedlich definiert, die Auswahlkriterien der Studienpopulation zum Teil unklar und nicht naher erlautert. Auch die Diagnosekritieren des Impingementsyndroms sind zum Teil uneinheitlich oder nicht klar definiert. In der Analyse zeigte sich eine breite Streuung in den angegebenen Werten fur die Sensitivitat und Spezifitat. Nur die haufig untersuchten Neer- und Hawkins-Kennedy-Tests zeigten reliable Ergebnisse. Die Analyse ergab, dass aufgrund der bisherigen Literatur kein Test eine hinreichende diagnostische Sicherheit als Screeningtest fur das Impingementsyndrom besitzt. Eine Kombination der klinischen Funktionstests kann zu einer Verbesserung der klinischen Diagnostik fuhren. Die Kombination verschiedener klinischer Tests dient als richtungweisendes diagnostisches Hilfsmittel. Zusatzliche Datenerhebungen, wie z. B. die Anamnese und die Durchfuhrung bildgebender Diagnostik (Sonographie, Rontgen, Magnetresonanztomographie) sind sinnvoll und empfehlenswert. Weitere prospektive und kontrollierte Studien mit einem einheitlichen Studienaufbau sind zur Evaluierung der klinischen Schultertests erforderlich.

Background Isolated patellofemoral arthroplasty is discussed controversially. The aim of this nation-wide survey in Germany and review of the literature was to determine the current status of patellofemoral arthroplasty. Methods A standardised questionnaire was sent to 744 German departments of orthopaedic surgery, traumatology and general surgery. In the first part, surgeons were asked general questions about their department size, case numbers of knee arthroplasties per year and non-endoprosthetic treatment of isolated patellofemoral disorders. If patellofemoral arthroplasty was conducted, parameters concerning age, gender, duration of complaints, indication for surgery, surgical approach, type of endoprosthesis used, additional surgical treatments and failures were evaluated in the second part. Furthermore we asked for the reasons if no isolated patellofemoral arthroplasty was performed. A systematic review of the literature was done including studies published until October 2007. The main inclusion criterion was the presentation of results after the implantation of a patellofemoral prosthesis for isolated patellofemoral osteoarthritis. Results A total of 225 analysable questionnaires were returned. Of 53,420 knee arthroplasties performed per year, only 195 (0.37 %) were isolated patellofemoral arthroplasties. The majority of patients (91 %) were between 40 and 80 years old. The aetiology of isolated patellofemoral osteoarthritis was believed to be idiopathic in 41 % and traumatic in 8 %. Patellofemoral dysplasia was held to be responsible in 47 % and patellofemoral instability in 4 % of the cases. The main reason for failure and surgical revision was ongoing tibiofemoral osteoarthritis of the affected knee. Negative attitude and disbelief towards the success of isolated patellofemoral arthroplasty were stated by the majority (62 %) of non-users. A lack of appropriate indications was reported by 22 % and lacking know-how by 16 %. We analysed 12 studies (459 implantations; 390 patients) in the literature review. The treatment was considered successful in 67.8 % of cases. The overall revision rate was 30.3 %. The highest failure rates were in patients with progression of tibiofemoral osteoarthritis or malalignment. Conclusions Isolated patellofemoral arthroplasty has only low significance among surgeons performing knee arthroplasty in Germany. The majority of surgeons do not believe in the success of the procedure. Almost one third of published cases in the literature needed to be revised.

Anterior knee pain is one of the most common problems after total knee arthroplasty (TKA). Mobile-bearing designs should improve patella tracking with a reduced rate of patella tilt as well as reduced patellofemoral contact stresses and improve knee flexion. The aim of this dynamic in vitro investigation was to evaluate the changes of patellofemoral contact stresses after TKA using fixed and mobile-bearing designs.Seven knee specimens were mounted into a knee simulator imitating an isokinetic extension of the knee. The patellofemoral contact was measured before and after tricompartimental TKA with fixed and mobile-bearing designs using pressure-sensitive films. Contact stresses were measured from 120 degrees knee flexion to full extension with a simulated force of the quadriceps muscle up to 1,200 N. Additionally all measurements were performed with simulated co-contraction of the hamstrings muscles.Fixed-bearing TKA increases patellofemoral contact stresses compared to physiologic conditions. After patella resurfacing, contact stresses increase even more. By changing the prosthesis design to mobile bearing, maximum contact stress was measured to be punctual higher than in fixed-bearing implants. In the interval between 0 degrees -30 degrees and 70 degrees -105 degrees of flexion, obviously lower pressures were evaluated for the mobile-bearing design. With cocontraction of the hamstrings, a lower contact stress of the mobile-bearing design was evident for the complete measurement of the knee extension.An increase of patellofemoral contact stresses after patellar resurfacing in TKA could be demonstrated. This outcome implicates a higher risk of patellofemoral complications. The mobile-bearing design showed evidently lower patellofemoral contact stresses than the fixed-bearing design.

We asked whether radiographic angles and signs of hip osteoarthrosis differ between radiographs of the pelvis taken in standing and supine positions. We retrospectively reviewed the radiographs of 61 patients (72 hips) with developmental dislocation of the hip. The minimum followup after closed reduction was 15 years (mean, 44 years; range, 15–64 years). We used pelvic radiographs in supine and standing positions taken at the same time and determined the following parameters: minimal joint space width, acetabular roof obliquity (AC angle), depth of the acetabulum (ACM angle), and center-edge angle. Osteoarthrosis was assessed according to Kellgren and Lawrence. Two independent observers measured all radiographs manually with a goniometer. AC angle, center-edge angle, and minimum joint space width differed between the radiographs taken in supine and standing positions at followup, whereas osteoarthrosis grading and the ACM angle did not. The AC angle depended on patient position and predicted development of osteoarthrosis. The minimum joint space width was influenced by the radiographic position with greater values in the supine position. ACM angle and the osteoarthrosis grade according to Kellgren and Lawrence were unaffected by the patient’s position. Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

© 2014, Springer-Verlag Berlin Heidelberg. Purpose: Meniscal injury resulting in segmental loss of meniscal tissue is a major risk factor for the development of osteoarthritis. Tissue engineering strategies have provided scaffolds for meniscal regeneration in order to establish a treatment option for patients with limited opportunities for meniscal reconstruction. The purpose of this study was to assess the clinical and magnetic resonance imaging (MRI) results 2 years after implantation of a polyurethane scaffold for chronic segmental medial meniscus deficiency following partial medial meniscectomy. Methods: Eighteen patients were treated with arthroscopic implantation of an ActiFit® (Orteq Sports Medicine) polyurethane meniscal scaffold for meniscus deficiency of the medial meniscus. Patients were followed up at 6, 12, and 24 months. Clinical outcome was assessed using patient-reported outcome scores (KOOS, KSS, UCLA activity scale, VAS for pain). Radiological outcome was assessed using MRI at 6, 12, and 24 months by evaluating scaffold morphology, scaffold integration, and additional joint injury, as well as joint inflammation. Results: Eighteen patients with a median age of 32.5 years (range 17–49) were enrolled. Statistically significant improvements were present in all patients, but one at 2 years compared to baseline in all categories. Complete resorption of the scaffold occurred in one patient representing a failure to treatment. MRI showed abnormal signal intensity of the scaffold when compared to residual meniscal tissue but without synovitis or joint inflammation. Extrusion of the scaffold was present in four patients. No correlation between scaffold extrusion and clinical outcome was observed. Conclusion: Arthroscopic implantation of a polyurethane meniscal scaffold in patients with chronic segmental medial meniscus deficiency is not only a safe procedure but leads to good clinical results at a 2-year follow-up. Scaffold extrusion did not appear to affect clinical outcome. Level of evidence: IV.

Osteoarthritis (OA) is a chronic, progressive disease resulting in loss of function and pain due to articular cartilage loss and represents the most common disease among musculoskeletal disorders [7, 8, 15]. Various strategies for the treatment for medial OA of the knee including conservative and operative treatment options are currently used. Surgical treatment includes, among others, high tibial osteotomy (HTO), unicompartmental knee arthroplasty (UKA), and total knee arthroplasty (TKA). Conservative treatment comprises a variety of different options including analgesic and/or anti-inflammatory medication, bracing, physiotherapy, and intra-articular injections of corticosteroids or viscosupplements. The general problem with conservative treatment is that despite amelioration of symptoms, the progressions of OA are usually unhalted [10]. London et al. [12] illustrated an additional problem: There are patients unwilling or unsuitable to undergo extensive surgery by means of arthroplasty or HTO. These patients are often young and show mild to moderate but symptomatic OA on radiographs that limits their inactivities of daily life, especially participation in recreational sports. These patients are reported to be within a “treatment gap” with no perfectly suitable treatment concept available [12]. A recently published survey illustrated that the majority of orthopedic surgeons are aware of this treatment gap and feel the need for a suitable treatment option for the young patient with symptomatic early osteoarthritis [11]. Recently, a new surgical implant was introduced for the treatment of medial knee osteoarthritis trying to address this treatment gap. The device consists of titanium alloy base plates rigidly attached to the medial aspect of tibia and femur connected to a cobalt/cobalt chrome alloy spring crossing the joint line. This is meant to reduce the load of the medial knee joint compartment while preserving the joint and not significantly affecting the lateral joint contact mechanics [6]. It was designed to reduce pain and stop progression of OA of the medial compartment [5]. Our purpose is to describe the clinical course of a 52-year-old patient implanted with this type of device. In this case, the device failed necessitating complete implant removal 18 months following implantation due to pain, metallosis, and penetration of the joint capsule.

The ideal treatment for juvenile osteochondritis dissecans of the talus (ODT) is still unclear. To determine predictors of failure of conservative treatment, children admitted for ODT were retrospectively analyzed. Patient files were analyzed to search for children treated for an ODT between 2000 and 2011. X-rays and MRI at baseline were evaluated for grading of lesions and the patient history was obtained. Final follow-up evaluation was performed via questionnaire and complementary telephone interview. Outcome was measured using the AOFAS and the Olerud/Molander scores. Conservative treatment consisted of out of sports and modification of activity under full weight-bearing. In case of persisting pain, full load removal on crutches was initiated. For further analysis, two groups were formed: (1) successful conservative treatment; (2) converted to surgical therapy. A logistic regression was used to determine potential predictors of conservative treatment failure. Seventy-seven lesions in 67 children with a mean age of 11.4 years (range 4–15 years) at the time of diagnosis were identified. Every patient received conservative treatment as a first-line treatment after diagnosis of ODT except for one single patient with a grade IV lesion at time of diagnosis who received operative treatment directly after diagnosis. Sixty-one percent of the lesions failed conservative treatment. A higher age as well as a grade III lesion at time of diagnosis was predictive for failure of the conservative treatment (p = 0.03 and p = 0.02, respectively). Regarding the functional outcome, a higher grade lesion in general was predictive for an inferior outcome as measured by clinical score. Grade III ODT especially in older children leads significantly more often to treatment failure when treated non-surgically. No other predictors for treatment failure could be identified. Level III (retrospective comparative study).

Balancing unicondylar knee arthroplasty (UKA) is challenging. If not performed properly, it may lead to implant loosening or progression of osteoarthritis in the preserved compartment. This study was aimed to document the biomechanical effects of improper balancing. We hypothesised that overstuffing would lead to more valgus, higher strain in the medial collateral ligament (sMCL), and higher lateral contact force. Six fresh-frozen cadaver specimens were mounted in a kinematic rig. Three motion patterns were applied with the native knee and following medial UKA (passive motion, open-chain extension, and squatting), while infrared cameras recorded the trajectories of markers attached to femur and tibia. Three inlay thicknesses were tested (8, 9, 10 mm). Overstuffed knees were in more valgus and showed less tibial rotation and higher strains in the sMCL (p

We report on three children with bilateral, congenital clubfoot. Four of the six clubfeet were associated with preaxial polydactyly. Five of the six clubfeet were treated without extensive surgery. A plantigrade foot was achieved, even in the three clubfeet with polydactyly, using serial casting and percutaneous Achilles tenotomy. Casting was adapted according to the existing polydactyly. One case with tibial hemimelia and a complex clubfoot deformity with preaxial tarsal polydactyly required more comprehensive surgery. A foot with good weight-bearing function was also achieved in this case following resection of the accessory medial ray, including resection of the accessory tarsal bones and posterior release. Remaining limitations in mobility were ascribed to hindfoot pathologies.

The present study was designed to evaluate the penetration of diclofenac sodium 4 % spray gel in synovial tissue, synovial fluid and blood plasma after topical application in subjects with joint effusions and planned total knee arthroplasty (TKA) due to osteoarthritis. A total of 39 patients were randomised to two- or three-times daily application of diclofenac sodium 4 % spray gel to knees requiring surgery over a treatment period of 3 days. Within 8 h after the last application, TKA was conducted, and the diclofenac concentrations in synovial tissue, synovial fluid and blood plasma were measured by liquid chromatography. The median diclofenac concentration was approximately 10–20-fold higher in synovial tissue (36.2 and 42.8 ng/g) than in synovial fluid (2.6 and 2.8 ng/mL) or plasma (3.9 and 4.1 ng/mL) in both treatment groups. Dose proportionality for any compartment or treatment groups could not be detected. Treatment-related adverse events were noted in two cases and limited to skin reactions. Diclofenac sodium 4 % spray gel was found to penetrate the skin locally in substantial amounts and thus reach the desired target tissue. Concentrations were not dose-dependent, and application was well tolerated by 97.4 % of patients. Topical application of diclofenac should be considered a valuable alternative to systemic NSAID therapy in the initial treatment of osteoarthritis.

STUDY DESIGN Immunohistological study. OBJECTIVE To elucidate the role of matrix metalloproteinases (MMPs), hypoxia-inducible factor-1α (HIF), and vascular endothelial growth factor (VEGF) in the hypertrophied ligamentum flavum (LF) obtained from patients with lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA The most common spinal disorder in the elderly is LSS, which results in part from LF hypertrophy. Although prior histologic and immunochemical studies have been performed in this area, the pathophysiology of loss of elasticity and hypertrophy is not completely understood. METHODS LF samples of 38 patients with LSS were harvested during spinal decompression. Twelve LF samples obtained from patients with disk herniation and no visible degeneration on preoperative magnetic resonance imaging were obtained as controls. Samples were dehydrated and paraffin embedded. For immunohistochemical determination of VEGF, HIF, and MMPs 1, 3, and 9 expression, slices were stained with VEGF, HIF, and MMP antibody dilution. Neovessel density and number of elastic fibers were counted after Masson-Goldner staining. LF hypertrophy and cross-sectional area (CSA) were measured on T1-weighted magnetic resonance imaging. RESULTS MMPs 1, 3, 9 and VEGF expression were significantly increased in the hypertrophy group (P

This pilot study used magnet resonance imaging (MRI) to analyse the rotation of medial unicondylar knee arthroplasty (UKA) components and assessed how accurately the results could be reproduced. Knee MRI using a special protocol to reduce metal artefact was performed in ten patients who had undergone medial UKA. Two independent investigators measured the rotation angle of femoral (zirconium) and tibial (cemented full-poly or cemented modular metal-backed) components applying different reference lines for the latter. Statistical analysis comprised tests for reliability, variance between measurement techniques, standard deviations and limits of agreement. For all methods tested, there was sufficient inter- and intra-observer reliability. Lowest variances were, however, found for the femoral epicondyles, for both femoral and tibial components. A tangent to the dorsal epicondyles of the tibia also gave reproducible results with low variances for the tibial component. Almost all applied measurement techniques were reproducible by statistical definition, although some of them resulted in substantial differences between both, observations and observers. A variance test helps to distinguish better between clinically useful and less accurate references. MRI allows good reproducible rotation analysis via the femoral epicondyles for both femoral and tibial UKA implants. For the tibia, the tibial tuberosity, the eminentia and the tibial epicondyles in particular were shown to be less reliable. The dorsal epicondyles seem to be most suitable for the tibial component.

Background The most common spinal disorder in the elderly is lumbar spinal stenosis (LSS), which results in part from ligamentum flavum (LF) hypertrophy. Although prior histologic and immunochemical studies have been performed in this area, the pathophysiology of loss of elasticity and hypertrophy is not completely understood. The purpose of this immunohistological study is to elucidate the role of CD44 and its splice variants CD44v5 and CD44v6 in the hypertrophied LF obtained from patients with lumbar spinal stenosis (LSS). Materials and methods LF samples of 38 patients with LSS were harvested during spinal decompression. Twelve LF samples obtained from patients with disc herniation and no visible degeneration on preoperative MRI were obtained as controls. Samples were dehydrated and embedded in paraffin. For immunohistochemical determination, slices were stained with antibodies against CD44, Cd44v4, and CD44v6 stained with DAB. LF hypertrophy and cross-sectional area (CSA) were measured with T1-weighted MRI. Results CD44 and CD44v5 expression were significantly increased in the hypertrophy group (p

Adequate graft fixation over a certain time period is necessary for successful cartilage repair and permanent integration of the graft into the surrounding tissue. The aim of the present study was to test the primary stability of a new cell-free collagen gel plug (CaReS(®)-1S) with two different graft fixation techniques over a simulated early postoperative period.Isolated chondral lesions (11 mm diameter by 6 mm deep) down to the subchondral bone plate were created on the medial femoral condyle in 40 porcine knee specimens. The collagen scaffolds were fixed in 20 knees each by press-fit only or by press-fit + fibrin glue. Each knee was then put through 2,000 cycles in an ex vivo continuous passive motion model. Before and after the 2,000 motions, standardized digital pictures of the grafts were taken. The area of worn surface as a percentage of the total collagen plug surface was evaluated using image analysis software.No total delamination of the scaffolds to leave an empty defect site was recorded in any of the knees. The two fixation techniques showed no significant difference in worn surface area after 2,000 cycles (P = n.s.).This study reveals that both the press-fit only and the press-fit + fibrin glue technique provide similar, adequate, stability of a type I collagen plug in the described porcine model. In the clinical setting, this fact may be particularly important for implantation of arthroscopic grafts.

Introduction Adequate migration and differentiation of mesenchymal stem cells is essential for regeneration of large bone defects. To achieve this, modern graft materials are becoming increasingly important. Among them, electrospun nanofiber scaffolds are a promising approach, because of their high physical porosity and potential to mimic the extracellular matrix (ECM). Materials and Methods The objective of the present study was to examine the impact of electrospun PLLA nanofiber scaffolds on bone formation in vivo, using a critical size rat calvarial defect model. In addition we analyzed whether direct incorporation of bone morphogenetic protein 2 (BMP-2) into nanofibers could enhance the osteoinductivity of the scaffolds. Two critical size calvarial defects (5 mm) were created in the parietal bones of adult male Sprague-Dawley rats. Defects were either (1) left unfilled, or treated with (2) bovine spongiosa, (3) PLLA scaffolds alone or (4) PLLA/BMP-2 scaffolds. Cranial CT-scans were taken at fixed intervals in vivo. Specimens obtained after euthanasia were processed for histology, histomorphometry and immunostaining (Osteocalcin, BMP-2 and Smad5). Results PLLA scaffolds were well colonized with cells after implantation, but only showed marginal ossification. PLLA/BMP-2 scaffolds showed much better bone regeneration and several ossification foci were observed throughout the defect. PLLA/BMP-2 scaffolds also stimulated significantly faster bone regeneration during the first eight weeks compared to bovine spongiosa. However, no significant differences between these two scaffolds could be observed after twelve weeks. Expression of osteogenic marker proteins in PLLA/BMP-2 scaffolds continuously increased throughout the observation period. After twelve weeks osteocalcin, BMP-2 and Smad5 were all significantly higher in the PLLA/BMP-2 group than in all other groups. Conclusion Electrospun PLLA nanofibers facilitate colonization of bone defects, while their use in combination with BMP-2 also increases bone regeneration in vivo and thus combines osteoconductivity of the scaffold with the ability to maintain an adequate osteogenic stimulus.

Background Long head biceps (LHB) degeneration, in combination with rotator cuff tears, can be a source of chronic shoulder pain. LHB tenotomy reduces pain and improves joint function although the pathophysiological context is not well understood. Tendon integrity depends on the extracellular matrix (ECM), which is regulated by matrix metalloproteinases (MMP). It is unclear which of these enzymes contribute to LHB but we chose to study MMP 1, 3, and 9 and hypothesized that one or more of them may be altered in LHB, whether diagnosed preoperatively or intraoperatively. We compared expression of these MMPs in both LHB and healthy tendon samples. Methods LHB samples of 116 patients with degenerative rotator cuff tears were harvested during arthroscopic tenotomy. Patients were assigned to 4 groups (partial thickness tear, full thickness tear, cuff arthropathy, or control) based upon intraoperative findings. Partial and full thickness tears were graded according to Ellman and Bateman's classifications, respectively. MMP expression was determined by immunohistochemistry. Results MMP 1 and 9 expression was significantly higher in the presence of rotator cuff tears than in controls whereas MMP 3 expression was significantly decreased. MMP 1 and 9 expression was significantly higher in articular-sided than bursal-sided partial thickness tears. No significant association was found between MMP 1 and 9 expression and full thickness tears, and the extent of the cuff tear by Bateman's classification. Conclusion Increased MMP 1 and 9 expression, and decreased MMP 3 expression are found in LHB degeneration. There is a significant association between the size and location of a rotator cuff tear and MMP expression.

The use of highly conforming polyethylene inlays in total knee arthroplasty (TKA) provides improved anteroposterior stability. The aim of this fluoroscopic study was to investigate the in vivo kinematics during unloaded and loaded active extension with a highly conforming inlay and a flat inlay after cruciate retaining (CR) total knee arthroplasty (TKA). Thirty one patients (50 knees) received a fixed-bearing cruciate retaining total knee arthroplasty (Genesis II, Smith & Nephew, Schenefeld, Germany) for primary knee osteoarthritis. Twenty two of them received a flat polyethylene inlay (PE), nine a deep dished PE and 19 were in the control group (physiological knees). The mean age at the time of surgery was 62 years. Dynamic examination with fluoroscopy was performed to assess the “patella tendon angle” in relation to the knee flexion angle (measure of anteroposterior translation) and the “kinematic index” (measure of reproducibility). Fluoroscopy was performed under active extension and flexion, during unloaded movement, and under full weight bearing, simulated by step climbing. No significant difference was observed between both types of polyethylene inlay designs and the physiological knee during unloaded movement. Anteroposterior (AP) instability was found during weight-bearing movement. The deep-dish inlay resulted in lower AP translation and a non-physiological rollback. Neither inlay types could restore physiological kinematics of the knee. Despite the fact that deep dished inlays reduce the AP translation, centralisation of contact pressure results in non-physiological rollback. The influence of kinematic pattern variability on clinical results warrants further investigation.

Background High tibial osteotomy (HTO) is a well established technique for the treatment of medial osteoarthritis of the knee with varus malalignment. Results of total knee arthroplasty (TKA) after previous HTO are still discussed controversially. The aim of this study was to elucidate the clinical and radiological results as well as perioperative data of prior HTO on TKA. Methods Forty-one TKA after HTO were compared to 41 primary TKA at minimum of six years follow-up. Patients were matched according to age, gender, follow-up, etiology, and prosthetic design. Surgical data and complications were evaluated. Clinical outcome was assessed using a number of clinical scores and the visual analogue scale (VAS) for pain. X-rays were evaluated by the method of the American Knee Society. The patellar position was measured by the Insall-Salvati ratio. Results There was no significant difference in mean operation time (p = 0.47) and complication rate (p = 0.08). The Knee Score of the KSS (p = 0.0007) and the ROM (p = 0.006 for extension and p = 0.004 for flexion, respectively) were significantly better in the control group. Mid-term results of the VAS, WOMAC, Lequesne, UCLA, Feller's Patellar Score and SF-36 showed no significant difference. Femoral and tibial component alignment were similar in both groups. One tibial component showed suspect radiolucencies in the HTO group. The Insall-Salvati ratio showed three patients with patella alta and one patient with patella baja in the HTO group. At latest follow-up all implants were still in place. Conclusions Evaluating the clinical and radiological outcome, significant differences were only detected for range of motion and the Knee Score of the KSS. The present study suggests that the results of TKA with and without prior HTO are mainly identical. Although patients with a previous HTO had more complications, no statistically significant differences were noted with this group size.

Differing extents of tendon retraction are found in full-thickness rotator cuff tears. The pathophysiologic context of tendon degeneration and the extent of tendon retraction are unclear. Tendon integrity depends on the extracellular matrix, which is regulated by matrix metalloproteinases (MMP). It is unknown which enzymes play a role in tendon degeneration. The hypotheses are that (1) the expression of MMPs 1, 3, and 9 is altered in the torn rotator cuff when compared with healthy tendon samples; and (2) that there is a relationship between MMP expression and the extent of tendon retraction in the torn cuff. Rotator cuff tendon samples of 33 patients with full-thickness rotator cuff tears (Bateman grade III) were harvested during reconstructive surgery. Samples were dehydrated and paraffin-embedded. Immunohistologic determination of MMP 1, 3, and 9 expression was performed by staining sample slices with MMP antibody. The extent of tendon retraction was determined intraoperatively according to Patte’s classification and patients were assigned to 4 groups (control group, and by tendon retraction grade Patte I-III). The control group consisted of six healthy tendon samples. Expression of MMPs 1 and 9 was significantly higher in torn cuff samples than in healthy tendons whereas MMP 3 expression was significantly decreased (P