Purpose To evaluate the clinical outcomes of patients with a minimum 2-year follow-up following contemporary patellofemoral inlay arthroplasty (PFIA) and to identify potential risk factors for failure in a multi-center study. Methods All patients who underwent implantation of PFIA between 09/2009 and 11/2016 at 11 specialized orthopedic referral centers were enrolled in the study and were evaluated retrospectively at a minimum 2-year follow-up. Clinical outcomes included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Tegner Scale, the visual analogue scale (VAS) for pain, and subjective patient satisfaction. Pre- and perioperative risk factors were compared among failures and non-failures to determine potential risk factors. Results A total of 263 patients (85% follow-up rate) could be enrolled. The mean age at the time of index surgery was 49 ± 12 years with a mean postoperative follow-up of 45 ± 18 months. The overall failure rate was 11% (28 patients), of which 18% (5 patients) were patients with patella resurfacing at index surgery and 82% (23 patients) were patients without initial patella resurfacing. At final follow-up, 93% of the patients who did not fail were satisfied with the procedure with a mean transformed WOMAC Score of 84.5 ± 14.5 points, a mean KOOS Score of 73.3 ± 17.1 points, a mean Tegner Score of 3.4 ± 1.4 points and a mean VAS pain of 2.4 ± 2.0 points. An increased BMI was significantly correlated with a worse postoperative outcome. Concomitant procedures addressing patellofemoral instability or malalignment, the lack of patellofemoral resurfacing at the index surgery and a high BMI were significantly correlated with failure in our patient cohort. Conclusion Patellofemoral inlay arthroplasty shows high patient satisfaction with good functional outcomes at short-term follow-up and thus can be considered a viable treatment option in young patients suffering from isolated patellofemoral arthritis. Patellar resurfacing at index surgery is recommended to decrease the risk of failure. Level of evidence Retrospective case series, Level IV.

High tibial osteotomy (HTO) is an increasing popular method to treat unicompartimental osteoarthritis of the knee in younger, active patients. In so doing one tries to delay the need for total or unicompartimental joint replacement. The augmentation of HTO opening gaps with supporting material is discussed controversially, especially after the introduction of locking plates, which contribute to the decline of the non-union rate. Currently, we do not recommend synthetic augmentation, when using locking plates in HTO with opening angles less than 10 degrees . In our recent randomized study we could histologically and radiologically demonstrate the complete rebuilding of lamelliform bone in patients without synthetic augmentation, whilst bony ingrowth into the hydroxyapatite/tricalcium phosphate (HA/TCP) wedge of augmented osteotomies just slowly progressed. In contrast to unaugmented osteotomies, there was no advantage in using HA/TCP wedges or the combination of HA/TCP wedges and platelet rich plasma (PRP) as supporting material after 12 months. In osteotomies where an opening angle bigger than 7.5 degrees is chosen, rigid locking plates should be used. In our opinion, autologous iliac crest graft should be used in the high-risk patients (obese, smoker, opening angle bigger than 10 degrees ). Whether synthetic augmentation combined with PRP is equal or even superior to autologous iliac crest graft in openings bigger than 10 degrees has not been proven yet.

Transgenicular osteotomy is an appropriate operative treatment for the correction of malalignment of the knee joint in unicompartment arthritis and instability. The evolution of operative techniques and hardware designs have led to a safer procedure and, therefore, to a wider range of indications. However, there is still a high failure rate following osteotomies when the biomechanic and biologic environments are not considered with adequate respect. The most common cause of failures and pitfalls and their solutions are described.

Humeral head fractures are very common among elderly people, often requiring shoulder arthroplasty. One requirement for good function after shoulder arthroplasty is an intact or at least reparable rotator cuff. In patients with multifractured and or osteoporotic tuberosities, refixation leads to the potential risk of redislocation and resorption of the tuberosities or coexisting irreparable rotator cuff tears lead to a high failure rate after implantation of traditional fracture prosthesis, whereas the reverse shoulder arthroplasty may provide better outcome. Here we report of a 79-year-old woman, who fractured both humeral heads at different times. Her right side was treated with a fracture prosthesis, which had to be converted after 2 years to a reverse shoulder prosthesis. Because of coexisting irreversible rotator cuff tear accompanying the second humeral head fracture on her left side, this patient was primarily treated with a reverse shoulder prosthesis. During the most recent follow up, 33 months after reverse shoulder arthroplasty on the left side and 39 months on the right side, the age- and gender-adapted constant score was 88 compared to 59 on the right side. The primary or secondary implantation of the reverse shoulder prosthesis in proximal humeral fractures has to be planned carefully, since long-term results are still lacking and treatment options after failed reverse shoulder arthroplasty are few. Generally, primary implantation of traditional fracture prosthesis is indicated in most cases of humeral head fractures; but in carefully selected cases primary reverse shoulder arthroplasty may be superior and lead to better outcome. Therefore, future research should be conducted to find criteria where the reverse shoulder arthroplasty is indicated as first line treatment of proximal humeral head fractures in elderly patients.

The purpose of this study is to clinically evaluate hamstring tendon anterior cruciate ligament (ACL)-reconstruction using femoral fixation with bioresorbable interference screws and with a bioresorbable transfixation device. The ACL-reconstruction using the transfixation device at the femoral side leads to less knee laxity and therefore to a better clinical outcome for the patient. Prospective randomized clinical outcome study. From February 2002 to December 2002, a total of 68 patients with hamstring ACL reconstruction using a femoral fixation once with TransFix (n=38; m:22 and f:16; median age=28.5 range 15–47) and the second with bioscrew (BS) (n=30; m:20, f:10; median age=25.5 range 13–61) completed the follow-up period. Patients in each group got a clinical assessment at 3, 6, and 12 months after surgery. The measurement of anterior translation of the tibia has been performed using the Rolimeter® device. No significant differences in the knee laxity testing using the Rolimeter device were seen between both groups and over time within these groups. Ninety percent of all patients had functionally normal or near normal International Knee Documentation Committee (IKDC) knee ligament ratings. The TF-group included 17 grade A, 19 grade B, and 2 grade C knees, and the BS-group had 12 grade A, 13 grade B, and 5 grade C knees. The IKDC rating, the OAK-score, the Tegner-activity-score, and the Lysholm-score did not show significant differences between the TF-group and the BS-group. We disproved our hypothesis that the transfixation technique leads to less laxity and therefore to a better clinical outcome when compared to the use of BS. The clinical results in this study clarified that this technique is an effective and safe method for femoral hamstring fixation in ACL-reconstruction. However, this technique revealed no advantage compared to the bioscrew fixation technique within the short-term follow-up.

OBJECTIVEMuscle-derived stem cells (MDSCs) isolated from mouse skeletal muscle exhibit long-time proliferation, high self-renewal, and multipotent differentiation. This study was undertaken to investigate the ability of MDSCs that were retrovirally transduced to express bone morphogenetic protein 4 (BMP-4) to differentiate into chondrocytes in vitro and in vivo and enhance articular cartilage repair.METHODSUsing monolayer and micromass pellet culture systems, we evaluated the in vitro chondrogenic differentiation of LacZ- and BMP-4-transduced MDSCs with or without transforming growth factor beta1 (TGFbeta1) stimulation. We used a nude rat model of a full-thickness articular cartilage defect to assess the duration of LacZ transgene expression and evaluate the ability of transplanted cells to acquire a chondrocytic phenotype. We evaluated cartilage repair macroscopically and histologically 4, 8, 12, and 24 weeks after surgery, and performed histologic grading of the repaired tissues.RESULTSBMP-4-expressing MDSCs acquired a chondrocytic phenotype in vitro more effectively than did MDSCs expressing only LacZ; the addition of TGFbeta1 did not alter chondrogenic differentiation of the BMP-4-transduced MDSCs. LacZ expression within the repaired tissue continued for up to 12 weeks. Four weeks after surgery, we detected donor cells that coexpressed beta-galactosidase and type II collagen. Histologic scoring of the defect sites 24 weeks after transplantation revealed significantly better cartilage repair in animals that received BMP-4-transduced MDSCs than in those that received MDSCs expressing only LacZ.CONCLUSIONLocal delivery of BMP-4 by genetically engineered MDSCs enhanced chondrogenesis and significantly improved articular cartilage repair in rats.

Introduction: The osteochondral transplantation (OCT) is a well accepted treatment option for focal cartilage lesions in the knee joint, whereas the fate of the transplanted cartilage is still unclear and the clinical outcome is variable. The purpose of this study was to evaluate the histological character of autologous transplanted cartilage and to correlate technical aspects and the patients’ history with the clinical outcome. Material and Methods: The OCT was performed in 27 patients (median age of 32 (22–43) years) with a focal chondral lesion at the medial femoral condyle. We investigated the clinical outcome after a median follow-up of 13.5 (5–28) months using the Lysholm-score and the integration of the transplanted plugs using an MRI-scoring system. Biopsy specimens from representative patients (n=8) were evaluated with histological staining and immunohistochemistry. Results: The median Lysholm-score was 80 (range 45–98). The wide range of the Lysholm-score in clinical outcome did not show significant differences in: follow-up, concomitant injuries, defect size or genesis. The MRI analysis revealed in all cases a regular osseous integration of the subchondral bone, but a failed chondral integration. The congruency of the plugs to the joint surface was often incorrect, however a correlation between the MRI-score and the clinical outcome could not be shown. Histology of the transplanted cartilage revealed small changes in immunohistochemistry after a relatively short-term follow-up, whereas the cartilage has still the typical hyaline character. Often, the surrounding cartilage consists of fibrous and granulation tissue. Conclusion: The congruency of the joint surface can not be restored to the original status, particularly in larger defects with irregular shapes. However, we did not find any aspects which affected the function of the knee joint following OCT. It can be assumed that remaining lesions at the surrounding cartilage could maintain the inflammatory process and therefore maintain the pain and a low knee function. Further investigations are needed to specify the effects of the OCT on the transplanted cartilage and its influence on the later clinical outcome.

Fractures in osteoporotic bones or segment defects are problematic bone lesions with a reduced biological capability of regeneration. We tested the hypothesis that cell-mediated ex vivo gene therapy to deliver BMP4 can heal critically sized defects and improve bone healing in osteoporotic rats. Primary muscle-derived cells were isolated from the hindlimb muscle of rats and retrovirally transduced to express bone morphogenic protein 4 (BMP4). The bone formation was evaluated following local application of these cells in critically sized defects and in fractures of osteoporotic bones. Radiographic ana lysis revealed bridging callus formation in a critically sized defect in all specimens using muscle-derived cells expressing BMP4 at 12 weeks. These findings were confirmed by histological evaluation, which revealed callus bone formation with good integration to the distal and proximal bone. Following treatment with muscle-derived cells expressing BMP4, the bone healing process in the osteoporotic bone was improved to the level similar to that of normal bone. The ex vivo gene therapy could be a promising tool for the treatment of osteoporotic fractures and critically sized defects. The reduced number of complications (nonunions, loss of reduction, and fragment dislocation), shortening of hospitalization period, and improvement of bone strength are decisive advocates for this treatment option.

In this study we have analyzed outcome during the early rehabilitation period phase following two different methods of anterior cruciate ligament (ACL) reconstruction: ligamentum patellae (LP) and semitendonosus/gracilis tendon (SG) based reconstruction. This study included 40 patients treated by each method, examined 6 weeks and 3, 6 and 12 months after surgery. Patients in the SG group showed significantly better Lysholm scores at 6 and 12 months, Tegner Activity Scale scores at 3 months, and pain profile assessments at 6 weeks and 3 months than those in the LP group. Significant differences were observed in LP group in range-of-motion at 6 weeks and 3 and 6 months post-surgery. Stability tests revealed no significant differences between patients in the two groups. SG-based reconstruction of the ACL thus demonstrated advantages over LP-based reconstruction regarding pain and function, while LP-based reconstruction was associated with an earlier return of motion.

(2004). Mennen clamp-on plate fixation of periprosthetic fractures of the humerus after shoulder arthroplasty—a report on 3 patients. Acta Orthopaedica Scandinavica: Vol. 75, No. 6, pp. 772-774.

Zusammenfassung Ziel der Knorpel-Knochen-Transplantation ist die Überführung von intaktem Knorpel aus wenig belasteten Gelenkarealen in Defektzonen der Hauptbelastungsregion. Trotz der fehlenden Integration des transplantierten Knorpels in das ortsständige Gewebe zeigen sich bei Probebiopsien und im Tierversuch histologisch hyaline Strukturen. Die mittelfristigen und wenigen Langzeitergebnisse stellen sich viel versprechend dar. Wichtig zur Therapieentscheidung sind die Genese, die Lokalisation und die Ausprägung des Knorpeldefekts. Traumatische, lokal umschriebene Knorpelläsionen des Femurkondylus Grad III–IV nach Outerbridge stellen die ideale Indikation dar, wobei die Transplantation auch in weiteren Gelenken mit unterschiedlichen klinischen Ergebnissen möglich ist. Eine Kontraindikation ist die generalisierte Osteoarthrose. Die Verminderung der Arthroseprogredienz durch die Knorpel-Knochen-Transplantation ist bisher nicht geklärt.

Background. The ideal cellular vehicle for use in cell-mediated gene therapy to enhance bone healing has not yet been identified. The purpose of this study was to compare the capacity of two types of cells transduced with retro-bone morphogenetic protein 4 (BMP4)-muscle-derived cells (MDCs) and unfractioned bone marrow stromal cells (BMSCs). Method. Primary rat MDCs and unfractioned rat BMSCs were transduced with a retrovirus to express BMP4. A 7-mm, critical-sized femur defect was created in adult rats, and 5x10(6) transduced cells were implanted into the femoral defect. Bone healing was monitored radiographically and histologically at 4, 8, and 12 weeks post-implantation. Results. All specimens in the MDC-BMP4 group and BMSC-BMP4 group showed a bridging callus at 8 and 12 weeks. At 12 weeks post-implantation the calluses of the MDC-BMP4 femora displayed significantly higher bone photodensity than the BMSC-BMP4 femora (P<0.05). Histomorphometry revealed no difference between the two treatment groups. However, non-union between newly formed and original bone was observed in none of the MDC femora but in six femora from the BMSC-BMP4 group. Conclusion. Both MDCs and unfractioned BMSCs can improve healing of a critical-sized bone defect following transduction of the cells with retroBMP4. However, MDCs appear to yield superior results when compared with BMSCs in terms of improved healing of segmental defects.

Background Ex vivo gene therapy can induce bone formation when delivery cells carrying the bone morphogenetic protein (BMP) gene are used. The hypothesis for this study was that the cell-mediated gene therapy could improve the healing of bony lesions with severe soft tissue damage. Method An animal model with a femoral osteotomy lesion associated with soft tissue damage was developed in rats. Muscle-derived cells, genetically engineered to express BMP4, were inserted within the osteotomy gap. Cells genetically engineered to express LacZ were used for the control group. The groups were subdivided with regard to the fixation method: stable and unstable fixation. The rats were killed for histological and radiographic evaluation 3 and 6 weeks post-surgery. Results No callus formation was found in the control group at any time point, whereas sufficient callus formation appeared in the treatment group after 6 weeks. A bridging callus with woven bone and hypertrophic chondrocytes was achieved in the treatment group when a stable fixation was used, but failed to appear in unstable fixation. Conclusion The combination of muscle-derived cells expressing BMP4 and a stable fixation were able to bridge the bone defect within 6 weeks, but with prolonged osteochondral ossification. Therefore, the ex vivo gene therapy could be an efficient biological approach to improve the treatment of bone lesions with severe soft tissue damage.

Cell-mediated gene therapy to deliver bone morphogenetic proteins (BMPs) offers several theoretical advantages over direct administration of the recombinant protein [1]. However, the ideal cellular vehicle to enhance bone healing in an immunocompetent animal have not yet been identified [2]. The purpose of the study was to evaluate the effect of muscle-derived cells transduced with retroBMP4 (MDC-BMP4) in comparison to the effect of unfractioned bone marrow cells transduced with retroBMP4 (BM-BMP4) in healing of a long bone defect in immunocompetent rats.

The anterosuperior labrum lesion of the shoulder without biceps anchor involvement is a rare injury, and it is unclear whether the refixation has advantages over resection. We describe the pathophysiology and treatment, and compare the functional outcome of these procedures of refixation and resection in 21 patients (median follow-up 6 months, range 5–16). The labrum was refixated in 11 cases. Clinical evaluation used the Constant score. Synovialitis in the area of the labral tear was detected in all cases. In refixation patients there was a significant postoperative improvement in Constant score (91.5 vs. 70). Débridement showed a greater increase in the Constant score range (92 vs. 48). An anterosuperior labrum lesion without involvement of the biceps anchor is a separate entity. The pathology is the consequence of degenerative labral lesions without loss of stability in the glenohumeral joint. In view of this background and the results of this study refixation of loose labral tears in anterosuperior labral lesions without loss of stability should not considered.