The Avantage ® dual mobility cup in primary total hip arthroplasty: A registry study.

Background: Avantage Cup has been widely used in dual mobility implants. However, in Swedish Registry, the outcome of the Avantage Cup is reported with higher implants revision compared to control. The aim of our study was to verify if the same results are present in the Registry of Prosthetic Orthopedic Implants (RIPO) of Emilia Romagna (ER, Italy), as the Avantage cup was the most implanted dual mobility cup for a long follow-up reported in this Registry (2000-2012). Furthermore, we assessed the survival rate of the implant over the time. Methods: We included all patients that underwent a primary THA using the Avantage cup during the period 2000-2020 in RIPO Registry. The survivorship of the primary THA implants was calculated and plotted according to Kaplan-Meier method. Results: 886 Avantage cups were included in the analysis. During the observational period 44 hips were revised. The most common reasons for revision were: periprosthetic fractures (PPF) (n = 7, 0.8 %), deep infection (n = 7, 0.8 %), and cup aseptic loosening (n = 13, 1.5 %).The survival rate of the implant was 96.8 % (95.3-97.8) at 5 years, 95.7 at 10 years (94.0-97.0) and 92.1 at 15 years (88.5-94.6). Conclusion: In conclusion, this study has demonstrated that the Avantage cup in primary hip arthroplasty implanted with a "friendly" femoral stem granted satisfactory long-term survival. Therefore, in the Swedish Registry, the cause of the poor results presented for Avantage Cup could be the thick, rough neck stem of the widely used Lubinus stem.

How evolution of the nailing system improves results and reduces orthopedic complications: more than 2000 cases of trochanteric fractures treated with the Gamma Nail System.

PURPOSE: The incidence of trochanteric fractures has increased significantly during the last few decades, especially in elderly patients with osteoporosis. The dynamic/sliding hip screw and the cephalomedullary nail are the most commonly used fixation methods to treat trochanteric fractures. The improvements in the Gamma Nail System (GNS) associated with a correct surgical technique reduced the postoperative orthopedic complications. The purpose of this study was to compare the results of the different Gamma Nails. METHODS: The present study is a retrospective analysis of 2144 patients treated with GNS between January 1997 and December 2011 for trochanteric fractures, classified according to AO classification method. The patients were divided into three groups according to the nailing system: 525 were treated with Standard Gamma Nail (SGN), 422 with Trochanteric Gamma Nail (TGN) and 1197 with Gamma3 Nail. RESULTS: The overall incidence of intra-operative complications was 1.21 %; the incidence of intra-operative complications for each group was 1.71 % for SGN group, 0.47 % for TGN group and 1.25 % for Gamma3 Nail group. The overall incidence of postoperative complications was 5.48 %, and the incidence for each group was 10.73 % for SGN group, 9.92 % for TGN group and 2.92 % for Gamma3 Nail group. CONCLUSION: The GNS is a safe device with a low rate of intra-operative complications. The evolution of this nail system reduces postoperative complications, thus improving the results at follow-up and confirming that the Gamma3 Nail is a safe and predictable device to fix trochanteric fracture.

Two-stage reimplantation for periprosthetic knee infection: Influence of host health status and infecting microorganism.

BACKGROUND: Two-stage revision is the gold standard treatment of TKA infection; nevertheless various factors may influence the success rate. The aim of our study was to assess the impact of the number of patient comorbidities together with virulence of infectious organism on prognosis of two-stage revision procedure in chronic peri-prosthetic knee infection; moreover we tried to demonstrate correlation between the presence of positive culture during re-implantation and re-infection rate. METHODS: Thirty-eight cases of two-staged revision procedures for infected total knee arthroplasty were prospectively followed. The presence of high virulence microorganisms on the culture result and the number (more than three) of comorbidities were used as major risk factors. All cases were divided into three groups: Group 1 (10 patients without major risk factors), Group 2 (18 patients with only one major risk factor), Group 3 (10 patients with both of major risk factors). RESULTS: After a mean follow-up of 65months (range 24-139months), there was infection recurrence in nine cases: four re-infections occurred with the same organism while five patients had re-infection with a different organism. Recurrence was higher in Group 3 (33% of the cases), lower in Group 2 (12% of the cases), whereas no infection occurred in Group 1. Finally in case of positive intraoperative cultures recurrence rate was 83%, whereas when specimens were negative we had only 12.5% of re-infections. CONCLUSIONS: Even if standard protocol of two-stage revision has demonstrated good results when treating low-virulence infections or patients without associated risk factors, its application to more challenging condition cannot be assumed. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of level of evidence.

Total knee arthroplasty for post-traumatic proximal tibial bone defect: three cases report.

Bone stock deficiency in primary as well as in revision total knee arthroplasty (TKA) represents a difficult problem to surgeon with regard to maintaining proper alignment of the implant components and in establishing a stable bone-implant interface. Different surgical procedures are available in these situations, for instances the use of bone cement, prosthetic augments, custom implant, and wire mesh with morsellized bone grafting and structural bone allograft. Structural allograft offers a numerous advantages as easy remodeling and felling cavitary or segmental defects, excellent biocompatibility, bone stock restoration and potential for ligamentous reattachment. In this article we report a short term result of three cases affected by severe segmental medial post/traumatic tibial plateau defect in arthritic knee, for which massive structural allograft reconstruction and primary total knee replacement were carried. The heights of the bone defect were between 27-33 mm and with moderate medio-lateral knee instability. Pre-operative AKS score in three cases was 30, 34 and 51 points consecutively and improved at the last follow-up to 83, 78 and 85 consecutively. No acute or chronic complication was observed. Last radiological exam referred no signs of prosthetic loosening, no secondary resorption of bone graft and well integrated graft to host bone. These results achieved in our similar three cases have confirmed that the structural bone allograft is a successful biological material to restore hemi-condylar segmental tibial bone defect when total knee replacement is indicated.

Total knee arthroplasty in stiff knee compared with flexible knees.

This retrospective study was done to evaluate the results of total knee arthroplasty performed on 32 patients with stiff knee, having a preoperative arc of movement between 0° and 50° (average 30°). This group of patients were matched with a group of 32 flexible knees, randomly selected from the same cohort of patients who underwent knee arthroplasty in our ward. At a mean follow-up of 4.5 years (min 2, max 11 years), seven patients of the stiff group reported complications (21.8% overall): four prosthetic infection that successively underwent removal of the implant, one skin necrosis 4 months after the intervention, one early contracture and one late stiffness of the knee. In the control group, in two cases, there was substitution of the implant due to periprosthetic infection. At the end of the study period, the clinical evaluation was not possible in four patients of the stiff and in two patients of the control group who underwent revision of the prosthetic components. An excellent or good clinical result was obtained in 92% of stiff group and in 96% of the control group patients. Although the final results achieved in these patients are worse than those of patients with flexible knee due to disadvantageous preoperative conditions and high complication rate, our results demonstrate the efficacy of the arthroplasty procedure as treatment of stiff knee.

Gap balancing versus measured resection technique using a mobile-bearing prosthesis in computer-assisted surgery.

Navigation has been developed to help surgeons install implants more accurately and reproducibly; at the same time, this tool is able to record quantitative information such as joint range of motion, laxity and kinematics intra-operatively. As for standard surgery, two strategies are possible to achieve either femoral component rotation or overall prosthetic alignment: a measured gap resection approach, in which bone landmarks are used to guide resections equal to the distal and posterior thickness of the femoral component, or a gap-balancing technique, in which equal collateral ligament tension in flexion and extension is tried to find before as a guide to final bone cuts. The purpose of this paper is to compare the two different methods in a 67 patients group submitted to the same procedure using mobile-bearing (MB) prosthesis in order to analyse the effect of both techniques on joint line maintenance, axial limb restoration and components position. The gap group (GG) consists of 31 patients in whom the arthroplasty was performed using a navigated gap-balancing technique. The measured group (MG) consists of 36 patients in whom a computer-assisted measured resection technique was used. The results of imaging and the number of outliers were not statistically different (P = 0.56) for the mechanical axis and prosthetic positioning between the two groups. The gap technique showed a statistically significant alteration of the post-operative value when compared with the measured resection technique, (P = 0.036). The mean elevation of the joint line was 4.09 mm for the GG and 3.50 mm in the MG.

Three-dimensional analysis of image-free navigation system for total knee arthroplasty.

Malalignment causes abnormal forces that may lead to loosening after knee replacement. Whether a computer-assisted technique can improve the precision of implant positioning guaranteeing good long-term results in total knee arthroplasty, this is a matter of discussion. The authors evaluate the alignment accuracy of 20 primary total knee arthroplasties, performed using an image-free computer navigation systems, with standardized CT protocol and three-dimensional digital model reconstruction. The results of this study demonstrate that the image-free navigation system is able to improve accuracy in axial limb alignment and positioning of the components in the majority of cases; moreover, the difference between the mean mechanical axis value of the navigation system (179.7° ± 1.7°) and the median mean value obtained during the post-operative evaluation (180.3° ± 1.9°) is not statistically significant (P = 0.28).

The potential role of metal ion release as a marker of loosening in patients with total knee replacement: a cohort study.

We investigated the role of ion release in the assessment of fixation of the implant after total knee replacement and hypothesised that ion monitoring could be a useful parameter in the diagnosis of prosthetic loosening. We enrolled 59 patients with unilateral procedures and measured their serum aluminium, titanium, chromium and cobalt ion levels, blinded to the clinical and radiological outcome which was considered to be the reference standard. The cut-off levels for detection of the ions were obtained by measuring the levels in 41 healthy blood donors who had no implants. Based on the clinical and radiological evaluation the patients were divided into two groups with either stable (n = 24) or loosened (n = 35) implants. A significant increase in the mean level of Cr ions was seen in the group with failed implants (p = 0.001). The diagnostic accuracy was 71% providing strong evidence of failure when the level of Cr ions exceeded the cut-off value. The possibility of distinguishing loosening from other causes of failure was demonstrated by the higher diagnostic accuracy of 83%, when considering only patients with failure attributable to loosening. Measurement of the serum level of Cr ions may be of value for detecting failure due to loosening when the diagnosis is in doubt. The other metal ions studies did not have any diagnostic value.

Early aseptic loosening of a porous tantalum knee prosthesis.

Porous tantalum represents a relatively new solution for primary and revision total knee arthroplasty, offering several unmatched properties. Tantalum is a transition metal, with excellent biocompatibility and bioactivity due to its intrinsic physical and structural characteristics. A widespread clinical use of porous tantalum tibial components for primary total knee arthroplasty has been partly hindered by the difficulty in removing this type of implant after bone in growth, often leading to a significant bone defect. On the contrary, in the case here reported, removal of the trabecular metal tibial component was unexpectedly easy at a 7-month follow-up due to the absence of bone ingrowth but with a complete preservation of the tibial plate bone stock. Causes for the lack of bone ingrowth are discussed.

Total knee arthroplasty in patients with poliomyelitis.

We performed a retrospective chart and radiograph review of 10 patients with a history of poliomyelitis involving a limb that subsequently underwent primary total knee arthroplasty between 2000 and 2008. One posterior stabilized (PS), two condylar constrained (CCK), and seven rotating hinge (RHK) prostheses belonging to the same system were implanted. Eight patients were followed for a minimum of 2 years (mean 4.3 years, range 2 to 8.5 years); one patient required revision for prosthesis infection. The last patient was followed for just six months reporting excellent pain relief, and without complications. American Knee Society Score (AKSS) improved postoperatively in all eight patients with at least 2 years follow-up. The improvement was more marked for the knee score, which increased from a mean of 37 points preoperatively (range 20 to 51) to 75.7 points postoperatively (range 50 to 92); for the functional score the mean increase was only 15.8 points, from a mean of 38.5 points (range 20 to 70) to 54.3 points (range 20 to 80) after the intervention. One patient had a recurrence of the recurvatum deformity after implanting a CCK prosthesis. We found that a rotating hinge prosthesis that allowed hyperextension was suitable treatment for patients with knee osteoarthritis and polio as this compensated for loss of quadriceps power.

Preliminary experience with electromagnetic navigation system in TKA.

Accuracy of implant positioning and precise reconstruction of leg alignment offers the best way to achieve good long-term results in total knee arthroplasty. Computer instrumentation was developed to improve the final position of the component and restore the mechanical axis. Current navigation systems use either optical or electromagnetic tracking. The advantage of the Electromagnetic (EM) navigation system is that no line-of-sight issues are present. However, special iron-free instruments are required. This report analyzes the postoperative radiological results of 32 knees treated using an EM system. All the measurements were recorded using software able to subtend angles automatically by five physicians, three radiologist and two orthopedic residents not involved with the surgery. Each radiograph was measured three times, in random order, and at delayed intervals. We found an ideal alignment for the mechanical axis (180+/-3 degrees ) in 30 out of 32 cases, whereas all the patients achieved a value of 90 degrees +/-3 degrees for both femoral and tibial frontal component angles. An apparently over-corrected implant position for the sagittal femoral component was reported, with a mean value of 11.2 degrees +/-3.6. The mean position of the tibial component was 90.6 degrees +/-2.8; just four measurements were outside of the +/-3 degrees of the desired value. EM is safe and there were no complications related to this system. An almost perfect correlation was found between the mechanical axis value of the EM navigation system (179.8 degrees +/-1.8) and the median value of the all reviewers (180.3 degrees +/-1.9) with a difference of 0.5 degrees .

Trabecular metal patella in total knee arthroplasty with patella bone deficiency.

This study evaluates results following patellar resurfacing using trabecular metal (TM) patella in marked deficiency or weakness of patellar bone that precludes patellar resurfacing with a standard cemented patellar button. Ten consecutive patients undergoing primary (3 cases) or revision (7 cases) total knee arthroplasty with patella augmentation were evaluated at a mean follow-up of 45 months (range 18-65). Nine patients had marked patellar bone deficiency and one had had previous patellectomy. No intra-operative complications occurred. There was no displacement of the patellar component and no patellar fractures when at least 50% of bone contact was possible. We observed loosening of the patella augmentation 17 months after the index procedure only in the case of previous patellectomy. When bone was present the fixation appeared excellent by radiographic evaluation already at 3 to 6 months after surgery; afterward bone contact was uniform in the peripheral regions in both lateral and Merchant radiographic views without signs of loosening. Finally, the mean Knee Society scores improved in all patients.

Long-term implant-bone fixation of the femoral component in total knee replacement.

Success of total knee replacement (TKR) depends on the prosthetic design. Aseptic loosening of the femoral component is a significant failure mode that has received little attention. Despite the clinical relevance of failures, no protocol is available to test long-term implant-bone fixation of TKR in vitro. The scope of this work was to develop and validate a protocol to assess pre-clinically the fixation of TKR femoral components. An in vitro protocol was designed to apply a simplified but relevant loading profile using a 6-degrees-of-freedom knee simulator for 1,000000 cycles. Implant-bone inducible micromotions and permanent migrations were measured at three locations throughout the test. After test completion, fatigue damage in the cement was quantified. The developed protocol was successfully applied to a commercial TKR. Additional tests were performed to exclude artefacts due to swelling or creep of the composite femur models. The components migrated distally; they tilted towards valgus in the frontal plane and in extension in the sagittal plane. The migration patterns were consistent with clinical roentgen-stereophotogrammetric recordings with TKR. Additional indicators were proposed that could quantify the tendency to loosen/stabilize. The type and amount of damage found in the cement, as well as the migration patterns, were consistent with clinical experience with the specific TKR investigated. The proposed pre-clinical test yielded repeatable results, which were consistent with the clinical literature. Therefore, its relevance and reliability was proved.

Interlocking nail for femoral shaft fractures: is dynamization always necessary?

A series of 179 closed femoral fractures treated by static interlocking nailing (Grosse-Kempf nail) was reviewed to evaluate the effect of dynamization on the time to bony union. In 75 patients, dynamization was performed whereas in 104 the implant was left static. Union occurred in 178 patients. We observed one infection. Time to union was significantly shorter in the static group (103 days) compared to the dynamized group (126 days).

The treatment of bone defects in primary arthroplasty of the knee.

The authors reviewed the literature as well as their own cases in order to discuss the indications, advantages and disadvantages relative to the methods used to treat bone defects in primary knee arthroplasty. An analysis shows that the use of cement represents the most unfavorable method from a mechanical point of view and it should thus be limited to defects that are not too deep and extensive. Bone grafts, both homoplastic and autoplastic, are preferred in younger patients. The former in lesions that are smaller, the latter in those that are larger. Currently, modular prostheses are diffusedly used because of their versatility and relatively low cost if we compare them with prostheses that are custom made. Finally, the authors emphasize the need to use intramedullary stems in bone defect with the purpose of reducing stress in the metaphyseal region.

Heterotopic ossifications subsequent to knee arthroplasty.

The occurrence of heterotopic ossifications constitutes a rare but possible complication in knee arthroplasty surgery. The authors retrospectively reviewed data for more than 250 patients submitted to knee arthroplasty with the purpose of ascertaining the incidence of the occurrence of heterotopic ossifications after surgery and of understanding any clinical repercussions and possible risk factors. A total of 14 cases of heterotopic ossifications were observed out of 276 knee arthroplasties (4.7%). Lesions were grade 1: 4, grade II: 3, grade III: 7. The authors stress the importance of local factors as compared to general ones and the need to adopt a respectful surgical method, avoiding notching or excessive trauma to the periosteum, as well as the need to define parameters in order to single out subjects at risk and in whom prophylaxis should be administered.

Closed-wedge tibial osteotomy: conventional technique versus a new system of compression-dynamic fixation.

Two groups of patients treated with different techniques of closed wedge tibial osteotomy were analyzed. Twenty-eight patients underwent the conventional technique and 31 patients underwent a closed-wedge osteotomy using a new osteotomy cutting jig and compression-dynamic fixation. The groups were comparable with respect to age, gender, and deformity. Using the conventional technique, only 68% of knees had an optimal postoperative femorotibial angle between 167 degrees and 175 degrees, compared to 88% using the new device (P=.02). High tibial osteotomy with an osteotomy jig provides a more accurate correction of deformity than the conventional technique.

Conjoined fracture-dislocation of the forearm at the elbow.

Conjoined fracture-dislocation of the elbow were first described by Marotte in 1982. In this study, a total of 41 patients treated between 1975 and 1995 at the Rizzoli Orthopaedic Institute and 4 patients treated between 1997 and 2000 at the Division of Orthopaedics at the Maggiore Hospital are evaluated. Based on the Marotte classification, the patients are divided into 4 groups, by site of dislocation of the radial capitellum and amount of comminution of the fracture of the ulna. A clinical and radiographic evaluation was made after a mean follow-up of 5.3 years based on Anderson criteria. The results obtained were excellent in 17 patients (37.8%) satisfactory in 13 (28.9%), dissatisfactory in 12 (26.7%); 3 patients were considered to be failures (6.7%), the best results were obtained in type I anterior dislocations.

Low-power diode laser stimulation of surgical osteochondral defects: results after 24 weeks.

The purpose of this study was to evaluate osteochondral lesions of the knee, treated intraoperatively with low-power laser stimulation, and assess results at 24 weeks. Surgery was performed under general anesthesia on six rabbits; a bilateral osteochondral lesion was created in the femoral medial condyles with a drill. All of the left lesions underwent immediate stimulation using the diode Ga-Al-As laser (780nm), whereas the right knees were left untreated as control group. After 24 weeks, the explants from the femoral condyles, either treated employing laser energy or left untreated, were examined histomorphometrically. Results obtained on the lased condyles showed good cell morphology and a regular aspect of the repaired osteocartilaginous tissue.

[Computerized tomography guided biopsy in the diagnosis of neoplastic and inflammatory lesions of the pelvis]. / La biopsia guidata con Tomografia Computerizzata nella diagnosi delle lesioni neoplastiche e infiammatorie del bacino.

PURPOSE: To assess the efficacy of percutaneous CT-guided biopsy in the diagnosis and therapeutic planning of neoplastic and flogistic diseases of the pelvis. MATERIAL AND METHODS: From July 1990 to December 1999 193 patients (113 males, 80 females: mean age 49, standard deviation 16) were submitted to CT-guided percutaneous biopsy of the pelvic region; 117 biopsies (61%) were performed at iliac, pubic and ischial segments and 76 (39%) at sacral region; 107 patients were admitted to the hospital and 86 were in clinic. Needles were 8 G (4 mm), 10 to 15 cm long. Approach to pelvic lesions was performed according to the specific site. Lesions of the lateral pelvic region have always been approached through the lateral surgical incision according to Enneking. Lesions of the posterior pelvic region have always been approached by the introduction of the needle along the posterior surgical incision according to Enneking. Lesions of the anterior region have always been approached through the anterior surgical incision according to Enneking. From July 1990 to May 1997 pelvic percutaneous biopsies have been carried out with a CT Sytec 3000. From May 1997 to December 1999 the device was replaced by a High Speed CTi. The introduction of spiral CT allowed reduction of performance mean time from 45 minutes (standard deviation 15) to 30 minutes (standard deviation 10). RESULTS: In 154 patients (80%) we observed a neoplastic, inflammatory or not classified degeneration. In 8 patients (4%) the retrieved material ended to be inadequate for a diagnosis. In 31 patients (16%) no disease was revealed at the histological examination. Such patients with negative histological examination have been kept under clinical and radiological control in the following period in order to verify the manifestation or the presence of an alteration previously not observed. On 31-3-2000 none of them had been submitted to a new percutaneous biopsy of the pelvic region. The overall mean accuracy has been 96% considering the negative patients as really negative. In 5 cases (2.6%) we have had complications represented by pain at the introduction and penetration site of the needle. DISCUSSION AND CONCLUSIONS: The choice of the needle, the approach to the lesion and the position of the patient are conditioned by the site of the tumor, its extension, the distance skin-neoplastic disease and by the respect of the incision lines of Enneking, in order not to complicate the job of the orthopaedic surgeon spreading tumoral cells outside the chosen surgical approach. The mean time of the procedure is 30 minutes (standard deviation 10). There are no absolute contraindications to percutaneous biopsy except the suspect or the presence of an hydatideal cyst. The risks have to be compared with those correlated with alternative methods or with the more concerning risk of a missed diagnosis. Complications in the literature range from 0% to 10%, the incidence varying according to the location; pain is the most frequent complication. Altogether the most negative event, although not a true complication, is the retrieval of an inadequate sample: the only drawback of percutaneous biopsy in comparison with incisional biopsy. The accuracy rate of percutaneous biopsy varies in relation to the involved anatomical region, to the pathological process, to the experience of the user, to the amount of the retrieved tissue and to the cooperation of the patient. Our experience shows that, in selected patients, percutaneous biopsy is a virtually safe and almost painless procedure which saves the patient from a surgical procedure in regional or general anestesia as for an incisional biopsy, and allows immediate planning and scheduling of a correct therapy for primitive or secondary neoplastic lesions.