Cell-free cartilage repair in large defects of the knee: increased failure rate 5 years after implantation of a collagen type I scaffold

INTRODUCTION

Cartilage defects of the knee remain a challenging problem in orthopedic surgery despite the ongoing improvements in regenerative procedures such as the autologous chondrocyte transplantation. Due to the lack of donor-site morbidity and the single-stage procedure cell-free scaffolds are an interesting alternative to cell-based procedures. But as currently mid- and long-term data are lacking, the aim of the present study was to present mid-term clinical, radiological and histological results of a cell-free collagen type I scaffolds for cartilage repair.

MATERIALS AND METHODS

Twenty-eight patients were followed prospectively. Clinical evaluation using patient-reported outcome measures (KOOS, IKDC; VAS for pain, Tegner score for activity) as well as radiologic evaluation of the repair tissue (MOCART) was performed at 1 year, 2 years and 5 years. Histologic evaluation of the repair tissue was done in case of revision surgery using the ICRS II score for human cartilage repair.

RESULTS

In these large cartilage defects with a mean defect size of 3.7 ± 1.9 cm², clinical failure necessitating revision surgery was seen in 5 of 28 patients (18%). While the remaining patients showed good-to-excellent clinical results (KOOS, IKDC, VAS, Tegner), the radiologic appearance of the repair tissue showed a reduction of the MOCART score between the 2- and 5-year follow-up. Histologic evaluation of the repair tissue showed a cartilage-like appearance with no signs of inflammation or cell death but an overall medium tissue quality according to the ICRS II Score.

CONCLUSION

The use of this cell-free collagen type I scaffold for large defects showed increased wear of the repair tissue and clinical failure in 18% of cases at 5-year follow-up.

Femoral tunnel widening is associated with tunnel malposition but not with clinical failure after medial patellofemoral ligament reconstruction with a free gracilis tendon graft

INTRODUCTION

MPFL reconstruction is widely and successfully used for treating patella instability, either as a standalone procedure or in combination. Although different techniques allow for MPFL reconstruction, the use of a free tendon graft is one of the most commonly used. The phenomenon of tunnel widening or tunnel enlargement is well described in ACL reconstruction, but so far only little effort has been put into evaluating this phenomenon after MPFL reconstruction.

MATERIALS AND METHODS

Patients who received an MPFL reconstruction with a free gracilis tendon graft were identified by review of patient files. Additional clinical examination and magnetic resonance imaging were performed to assess tunnel enlargement and clinical outcome.

RESULTS

Fifty-one knees of 49 patients (34 female, 17 male) with a mean follow-up of 3.0 ± 1.4 years were included in this study. Mean age at the time of surgery was 22.6 ± 8.5 years. Mean Tegner score decreased from preoperative 5.3 ± 2.0 to 4.0 ± 1.4 postoperative. Postoperative IKDC and Kujala scores were 74 ± 16 and 80 ± 15, respectively. Twenty-three patients showed a tunnel enlargement at follow-up examination. Of these 23 patients, 20 showed a tunnel that was positioned too proximal, whereas only 13 of the 28 patients showing no enlargement had a tunnel that was positioned too proximal (p = 0.0033). Interestingly, patients showing a tunnel enlargement at follow-up examination also showed significantly better Kujala (84 ± 12 vs. 75 ± 16; p = 0.03) and IKDC scores (80 ± 7 vs. 70 ± 19; p = 0.02) when compared to the non-enlarged group.

CONCLUSION

Tunnel enlargement after MPFL reconstruction with a free gracilis tendon graft seems to be connected to mechanical overload due to a proximal malposition of the femoral tunnel. Interestingly, this did not influence clinical outcome as patients with tunnel enlargement showed better Kujala and IKDC scores.

Oxidised zirconium versus cobalt alloy bearing surfaces in total knee arthroplasty: 3D laser scanning of retrieved polyethylene inserts

AIMS

We sought to establish whether an oxidised zirconium (OxZr) femoral component causes less loss of polyethylene volume than a cobalt alloy (CoCr) femoral component in total knee arthroplasty.

MATERIALS AND METHODS

A total of 20 retrieved tibial inserts that had articulated with OxZr components were matched with 20 inserts from CoCr articulations for patient age, body mass index, length of implantation, and revision diagnosis. Changes in dimensions of the articular surfaces were compared with those of pristine inserts using laser scanning. The differences in volume between the retrieved and pristine surfaces of the two groups were calculated and compared.

RESULTS

The loss of polyethylene volume was 122 mm³ (standard deviation (sd) 87) in the OxZr group and 170 mm³ (sd 96) in the CoCr group (p = 0.033). The volume loss in the OxZr group was also lower in the medial (72 mm³ (sd 67) versus 92 mm³ (sd 60); p = 0.096) and lateral (49 mm³ (sd 36) versus 79 mm³ (sd 61); p = 0.096) compartments separately, but these differences were not significant.

CONCLUSION

Our results corroborate earlier findings from in vitro testing and visual retrieval analysis which suggest that polyethylene volume loss is lower with OxZr femoral components. Since both OxZr and CoCr are hard surfaces that would be expected to create comparable amounts of polyethylene creep, the differences in volume loss may reflect differences in the in vivo wear of these inserts. Cite this article: Bone Joint J 2017;99-B:793-8.

[Current Diagnostics and Treatment of FAI in Germany]

AIM

Femoroacetabular impingement (FAI) is a recently proposed mechanical concept for the development of osteoarthritis of the hip. Aim of this nationwide survey is the description of the current status of diagnostics and therapy of FAI in Germany.

MATERIAL AND METHODS

All orthopedic and traumatological hospitals listed in the "list of German hospitals 2006" were invited via e-mail to take part in this anonymous survey.

RESULTS

The questionnaire was answered by 682 departments (50.5 %). 98 (14.3 %) of these departments treated FAI in 2007.

CONCLUSION

In Germany, diagnostics and treatment of FAI were performed inconsistently in a small number of specialized hospitals.

[Primary hip and knee replacement: time required for surgical training]

BACKGROUND

The aim of the present study is to analyse the increased surgical time required due to supervised surgery as an element of costs of education.

MATERIAL AND METHODS

Incision to closure times of 353 primary hip and knee prostheses were evaluated according to educational level. Differences between planned and real operation times were recorded, and the mean DRG proceeds per minute of surgical time were determined.

RESULTS

The difference between incision to closure times of the board certified surgeons for the respective surgical interventions and that of the supervised surgery is statistically significant (p<0.01) and clinically relevant (+15 min for THA, +13 min for TKA). The correlation between planned and real operation time was significantly lower in the category of supervised surgery.

CONCLUSION

There is an increased surgical time required for surgical training. It is the responsibility of health care policy to ensure an appropriate financial compensation.

CD44: survival and metastasis in chondrosarcoma

OBJECTIVE

Recent studies have shown abnormal expression of CD44s and some of its isoforms in many human malignancies, but little is known about the presence of CD44 in chondrosarcoma. In this study the expression of CD44s and two variant isoforms was evaluated. It was assumed that abnormalities in these receptor proteins may be associated with clinical outcome of the patients.

METHOD

Thirty paraffin-embedded chondrosarcoma samples were immunostained with monoclonal antibodies for CD44s, CD44v5 and CD44v6. Two independent examiners who were unaware of the clinical status of the patients evaluated the immunohistochemical results. The percentage of CD44-positive cells was scored semiquantitatively. A rate of higher than 10% was considered as overexpression.

RESULTS

Among the 30 patients (median age 50 years) there were 22 conventional chondrosarcomas, two dedifferentiated chondrosarcomas, two extraskeletal chondrosarcomas, and one periostal, mesenchymal, clear cell and myxoid chondrosarcoma each. In the immunochemistry staining overexpression (>10% of cells) of CD44s was shown in 56.7% (17 of 30), of CD44v5 in 43.3% (13 of 30) and of CD44v6 in 6.7% (two of 30) of the tumors. Four grade III chondrosarcomas (80%) and 10 (71.4%) grade II chondrosarcomas showed overexpression for CD44s, whereas CD44s was overexpressed in only three (27.3%) grade I chondrosarcomas. Cox regression suggests overexpression of CD44s to be an additional prognostic marker for chondroid bone tumors independent of grading and other covariates.

CONCLUSIONS

Overexpression of CD44s correlated significantly with metastatic potential and with poorer survival in patients with chondrosarcoma. CD44s might be an independent additional marker, but small sample size remains to be considered.

[Anterior shoulder instability--the current situation]

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<0.001).

CONCLUSION

The operative shoulder stabilisation is most frequently carried out as arthroscopic Bankart repair. A standardised, subsequent treatment is well established.

[Modular noncemented femoral stem system in revision total hip arthroplasty]

BACKGROUND

In most cases, loosening of a prosthesis stem is accompanied by periprosthetic osteolysis. This article presents the short-term clinical and radiological results after revision of total hip arthroplasty (THA) with bone substance deficiencies using a modular noncemented femoral stem system (LINK MP).

PATIENTS AND METHODS

Between March 2003 and November 2005, 91 LINK MP modular revision stems were implanted in 90 patients. Eighty-one patients (51 stem revisions, 24 revisions of stem and shell, and six reimplantations after a Girdlestone situation) were available for prospective clinical and radiological evaluation at an average follow-up time of 16.7+/-6.5 (6-36) months. The average patient age at revision was 67.2+/-10.5 (31-87) years.

RESULTS

Bone defects in the proximal femur were evaluated according to the Paprosky classification and showed type 2 in five cases, type 3A in 73 cases, and type 3B in three cases. The Merle d'Aubigné score increased significantly from 10.4+/-2.3 (4-15) preoperatively to 14.7+/-2.2 (9-18) at the latest follow-up (p<0.001). Migration analysis in conventional radiographs revealed an average stem subsidence of 3.4 mm. Thirty-one intraoperative and postoperative complications were noted in 28 (34.5%) patients.

CONCLUSION

After a short-term follow-up, the modular noncemented femoral stem system LINK MP was shown to be a reliable tool for revision of THA with bony defects of the proximal femur. Our results are comparable to those for other modular noncemented revision stems. As expected, complication rates were higher than with primary THA.

[Matched pair analysis: Innex FIXUC vs. NexGen LPS]

AIM

The aim of the present retrospective matched pair study was to compare the clinical results of patients undergoing total knee arthroplasty (TKA) with 2 different operation strategies: tibia first vs. femur first for ligament balancing and rotational alignment of the femoral component.

METHODS

In this study 30 patients underwent TKA with the fixed bearing prosthesis Innex FIXUC between 2003 and 2005. In the same period of time the posterior stabilised prosthesis NexGen LPS was implanted in 123 patients. Out of these, 30 patients were matched to the 30 patients of the Innex group based on the parameters age, gender, height, weight and BMI. All implants were cemented. Clinical examination was rated using UCLA score, Knee Society score, Lequesne score for knees, a visual analogue scale (VAS) for pain and the Feller patellar score. Three patients in the Innex group were lost to follow-up, and 27 matched pairs could finally be analysed.

RESULTS

At a mean follow-up of 25 months (Innex) and 3 years (NexGen) statistically significant differences (p < 0.05) with advantages for the NexGen were found in the UCLA activity score (4.9 vs. 5.9, p = 0.013), in part A (knee score) of the Knee Society score (78.9 vs. 91.0, p = 0.002) as well as the total score (153.9 vs. 173.2, p = 0.012), VAS (2.1 vs. 0.6, p = 0.003) and in the Lequesne knee score (5.7 vs. 3.6, p = 0.024). No statistically significant differences (p < 0.05) were found in the function score of the Knee Society score and the patellar score (Feller).

CONCLUSION

In the described setting there were functional advantages for the NexGen prosthesis (femur first) at a comparable revision rate. However, satisfactory results with the Innex FIXUC are possible, too.

The inhibitory effect of bupivacaine on prostaglandin E(2) (EP(1)) receptor functioning: mechanism of action

Prostaglandin E(2) receptors, subtype EP(1) (PGE(2)EP(1)) have been linked to several physiologic responses, such as fever, inflammation, and mechanical hyperalgesia. Local anesthetics modulate these responses, which may be due to direct interaction of local anesthetics with PGE(2)EP(1) receptor signaling. We sought to characterize the local anesthetic effects on PGE(2)EP(1) signaling and elucidate mechanisms of anesthetic action. In Xenopus laevis oocytes, recombinant expressed PGE(2)EP(1) receptors were functional (half maximal effect concentration, 2.09 +/- 0.98 x 10(-6) M). Bupivacaine, after incubation for 10 min, inhibited concentration-dependent PGE(2)EP(1) receptor functioning (half-maximal inhibitory effect concentration, 3.06 +/- 1.26 x 10(-6) M). Prolonged incubation in bupivacaine (24 h) inhibited PGE(2)-induced calcium-dependent chloride currents (I(Cl(Ca))) even more. Intracellular pathways were not significantly inhibited after 10 min of incubation in bupivacaine. But I(Cl(Ca)) activated by intracellular injection of GTPgammaS (a nonhydrolyzable guanosine triphosphate [GTP] analog that activates G proteins, irreversible because it cannot be dephosphorylated by the intrinsic GTPase activity of the alpha subunit of the G protein) was reduced after 24 h of incubation in bupivacaine, indicating a G protein-dependent effect. However, inositol 1,4,5-trisphosphate- and CaCl(2)- induced I(Cl(Ca)) were unaffected by bupivacaine at any time points tested. Therefore, bupivacaine's effect is at phospholipase C or at the G protein or the PGE(2)EP(1) receptor. All inhibitory effects were reversible. We conclude that bupivacaine inhibited PGE(2)EP(1) receptor signaling at clinically relevant concentrations. These effects could, at least in part, explain how local anesthetics affect physiologic responses such as fever, inflammation, and hyperalgesia during the perioperative period.