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).

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.

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.

Local and systemic control in Ewing's sarcoma of the femur treated with chemotherapy, and locally by radiotherapy and/or surgery.

The role of radiotherapy and/or surgery in the local treatment of Ewing's sarcoma has still to be determined. The outcome of Ewing's sarcoma may differ according to its location and a selection bias towards surgery limits the ability to compare methods of local treatment. We have carried out a retrospective review of 91 consecutive patients treated for non-metastatic Ewing's sarcoma of the femur. They received chemotherapy according to four different protocols. The primary lesion was treated by surgery alone (54 patients), surgery and radiotherapy (13) and radiotherapy alone (23). One was treated by chemotherapy alone. At a median follow-up of ten years, 48 patients (53%) remain free from disease, 39 (43%) have relapsed, two (2%) have died from chemotherapeutic toxicity and two (2%) have developed a radio-induced second tumour. The probability of survival without local recurrence was significantly (p = 0.01) higher in patients who were treated by surgery with or without radiotherapy (88%) than for patients who received radiotherapy alone (59%). The five- and ten-year overall survival rates were 64% and 57%, respectively. Patients who were treated by surgery, with or without radiotherapy, had a five- and ten-year overall survival of 64%. Patients who received only radiotherapy had a five- and ten-year survival of 57% and 44%, respectively. Our results indicate that in patients with Ewing's sarcoma of the femur, better local control is achieved by surgical treatment (with or without radiotherapy) compared with the use of radiotherapy alone. Further studies are needed to verify the impact of this strategy on overall survival.

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.

Primary osteogenic sarcoma of the clavicle. Case report.

The clavicle is an unusual site for any primary bone tumor, including osteogenic sarcoma. The authors report the case of a young girl aged 13 years who was affected with primary osteogenic sarcoma of the right clavicle, and who was treated by preoperative and postoperative chemotherapy and radical clavicle excision, including the acromioclavicular and the sternoclavicular joints.

[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.

Patellar height after high tibial osteotomy.

We analysed two series of patients affected by unicompartmental arthrosis or axial malalignment of the knee treated with two different techniques of high tibial osteotomy. Forty-seven knees were treated with a closing wedge osteotomy (CWO) and 40 with an opening wedge osteotomy (OWO). The two groups were comparable with respect to age, gender and deformity. For each patient the patellar height was measured by Caton's method before surgery, and at the latest assessment (at least 1 year after operation). The correction rate for the two series was analysed to assess any possible correlation between the variation of the patellar height and the degree of correction of the knee axis. We concluded that a high tibial osteotomy modifies the patellar height and that this depends on the technique employed. Patellar 'lowering' occurred more often with OWO than with CWO and the latter also produced a high degree of patellar elevation.

Intramedullary osteosynthesis after external fixation.

The authors report the results of a retrospective study conducted on 30 cases of fracture of the tibia and femur submitted to external fixation and subsequently to intramedullary osteosynthesis, treated between 1991 and 1999. Intramedullary osteosynthesis was used in 24 cases (5 in the femur and 19 in the tibia) as treatment subsequent to external fixation for nonunion or delays in consolidation. Sequential nailing was used as planned treatment in the remaining 6 cases. In 83.3% of cases the fracture was open (Gustilo Anderson type I (30%), type II (20%), type III (33.3%). The mean duration of external fixation was 13.24 weeks, and infection occurred in 4 cases (13.33%) during that time. Removal of the external fixator and intramedullary osteosynthesis were carried out during the same surgical session in 40% of the cases, while nailing was preceded by a period in plaster lasting an average of 4 weeks in the remaining 60% of cases. All of the cases achieved consolidation an average of 31 weeks after trauma, and 14.7 weeks after intramedullary synthesis. We observed the occurrence of infection in 3 cases (10%), but this did not keep consolidation from occurring.

Free microvascular flaps in oncological surgery of the limbs.

Surgery plays a role of primary importance in the treatment of sarcomas of the soft tissues. The first objective of surgical treatment is the local control of the disease. Local recurrence is a serious event, that often requires amputation, and favors metastatic progression of the disease. Currently, except in very rare cases, conservative treatment is the treatment of choice, as it has by now been demonstrated that its results are equivalent to those obtained when demolitive surgery is used. In the distal sites of the limbs, superficial localization of the tendons, ligaments, and joints, the absence of anatomical compartments, make it difficult to perform wide conservative surgery. To this must be added that patients are often sent to see a specialist after a previous inadequate operation, and the presence of a contaminated surgical scar often requires exeresis of a wide area of the skin, sufficient to obstruct healing by primary intention. The use of revascularized free flaps allows for oncologically adequate conservative surgery to be performed, even in anatomical sites where amputation alone traditionally provided a safe surgical margin.

Osteoid osteoma of the lumbar spine. A case report.

The authors report the case of a patient aged 10 years with late diagnosis of osteoid osteoma localized in the right pedicle of L1 due to a paucisymptomatic and aspecific clinical onset, characterized only by the occurrence of left-convex wide-range scoliosis that was completely solved after surgical excision of the neoformation.

[Computerized tomography assessment of femoral and tibial rotation in total knee prosthesis]. / Valutazione con Tomografia Computerizzata della rotazione delle componenti femorale e tibiale nell'artroprotesi totale del ginocchio.

PURPOSE: CT assessment of the axial deviation of the femoral and tibial prosthetic components in total knee arthroplasty. MATERIAL AND METHODS: January to July 1999, seventeen patients, 10 males and 7 females, mean age 66 years (standard deviation +/- 4) were examined after total knee arthroplasty. Exclusion criteria were prosthesis loosening and severe (equal or superior to 7 degrees) varus or valgus deviation. All patients were examined with knee radiography in the standing position completed by axial projections of patella and by CT scanning. We used a modification of Berger technique and carried out comparative CT scans extended lower limbs and acquisitions perpendicular to the mechanical axis of the knee, from the femoral supracondylar region down to the plane crossing the distal end of the tibial prosthetic component. Reference lines were then drawn electronically on given scanning planes to reckon the axial deviation of the femoral and tibial prosthetic components. RESULTS: Six patients, one female and 5 males, with normal rotational values of femoral and tibial prosthetic components presented no clinical symptoms. Eight patients, 4 females and 4 males, with abnormal values presented the following clinical symptoms: medial impingement, (incomplete) dislocation patella, and lateral instability. One female patient with a normal rotational value of femoral prosthetic component and an altered value of tibial prosthetic component presented medial impingement. Finally two patients, one female and one male, were absolutely asymptomatic although the rotational values of the two prosthetic components were beyond the normal range. CONCLUSIONS: Total knee arthroplasty is presently a standard treatment for many conditions involving this joint. There are several possible postoperative complications, namely fractures, dislocations (a)septic loosening and femoropatellar instability. The latter condition is the most frequent complication among implant failures and is caused by bad orientation of the femoral and tibial components on frontal and axial planes. We measured the orientation of the prosthetic components introducing a CT procedure which modifies the uniarticular with four scans introduced by Berger. The new method uses Berger's parameters and the CT study of both joints by means of Helical CT. With a single examination lasting less than 4 minutes and with the patient in a more comfortable position, we can obtain: 1) comparative and simultaneous assessment of the contralateral joint; 2) several scans to better define Berger's parameters and to accomplish measurement of the rotational deviation with higher precision and markedly decreasing the error margin. The analysis of the results confirms the international literature findings and especially the fundamental importance in positioning both prosthetic components within normal values, as emphasized by the relationship between the clinical symptoms and the rotational degree of the femoral and tibial prosthetic components.

Supracondylar fracture of the femur following total knee arthroplasty. Description of two clinical cases.

The authors describe two cases of supracondylar fracture of the femur occurring following total knee arthroplasty. By reviewing the literature, they analyze causal factors indicating the constant presence, observed also in the cases presented, of an erroneous resection of the anterior cortex of the femur. In association with other predisposing factors, this condition favors an anomalous distribution of the load forces in this site, reducing torsion resistance of the femur by about 30%: what results is greater susceptibility for the risk of fracture for a long period of time, even for trauma of moderate entity.