Can a target zone safer than Lewinnek's safe zone be defined to prevent instability of total hip arthroplasties? Case-control study of 56 dislocated THA and 93 matched controls.

BACKGROUND: Various factors contribute to instability of total hip arthroplasty (THA), with implant orientation being a major contributor. We performed a case-control study with computed tomography (CT) data to determine whether: 1) orientation contributes to THA instability and 2) a safer target zone for stability than Lewinnek's classic safe zone can be defined. MATERIAL AND METHODS: We included prospectively 363 cases of THA dislocation that occurred during the calendar 2013 year in 24 participating hospitals. Of the 128 dislocations that occurred in patients who underwent THA at these centers, 56 (24 anterior, 32 posterior) had CT scans, thus were included in the analysis. The control group was matched 4:1 based on implant type, year of implantation, age, sex, bearing types and THA indication. Of the 428 matched control THA cases, 93 had CT scans. In all, the CT scans from 149 cases (56 unstable, 93 stable) were analyzed to determine the acetabular cup's inclination and anteversion, and the femoral stem's anteversion. RESULTS: In the unstable THA group, cup inclination was 46.9°±7.4°, cup anteversion was 20.4°±10.8° and stem anteversion was 14.2°±9.9°. In the stable THA group, cup inclination was 44.9°±5.3° (P=0.057), cup anteversion was 22.1°±5.1° (P=0.009) and stem anteversion was 13.4°±4.4° (P=0.362). The optimal total anteversion (cup+stem) of 40-60° was achieved in 16.5% of unstable THA cases and 13.9% of stable THA cases, thus this parameter does not predict stability (odds ratio [OR] of 0.40, P=0.144). The cup was positioned in Lewinnek's safe zone in 44.6% of patients in the unstable group and 68.2% of those in the stable group (OR 3.74, P=0.003). A target zone defined as 40-50° inclination and 15-30° anteversion was better able to distinguish between unstable cases (23.2%) and stable cases (71.6%) resulting in an OR of 13.91 (P<0.001). DISCUSSION: Implant positioning was the only risk factor for instability found in this study. Moreover, our findings reinforce the theory put forward by other authors that Lewinnek's safe zone is not specific enough to differentiate between stable and unstable THA implantations. The target zone for acetabular cups proposed here (40-50° inclination and 15°-30° anteversion) is related to a lower risk of instability. This orientation can be used as a guide, but must be combined with other technical elements to optimize stability. By balancing stability and biomechanics, the 40-50° inclination and 15°-30° anteversion target zone redefines the optimal positioning window. LEVEL OF EVIDENCE: III case-control study.

Postoperative infections after limb-sparing surgery for primary bone tumors of the pelvis: Incidence, characterization and functional impact.

INTRODUCTION: Surgical site infections (SSI) represent the most common postoperative complication after limb sparing surgery for primary malignant bone tumors, with incidence ranging from 10 to 47%. There is no consensus concerning about the optimal surgical strategy, or the adequate antibiotic prophylaxis in pelvic resections. A greater knowledge of these infections and their surgical trajectories seem essential to obtain. MATERIALS AND METHODS: We retrospectively studied 45 cases of pelvic resection, including at least the periacetabular zone 2 of Enneking, performed between 1989 and 2013 in the same center. Infection rate, risk factors and surgical trajectories were analyzed. The impact of a postoperative infection on the quality of life and functional recovery was evaluated by the Musculoskeletal Tumor Society scoring system (MSTS). RESULTS: Sixteen patients presented a SSI in the first post-operative year (35.6%). We found as risk factors the pre-operative ASA score, the age at surgery and the number of packed red cells transfused during surgery. In case of failure of an initial washout, an iterative procedure is responsible for a high failure rate of 88.9%. Irrespective of the type of reconstruction, our functional results show that this surgery is often a source of handicap with a MSTS score of 13.77 in infected patients versus 17.70 in non-infected patients, at two-year follow-up. DISCUSSION: In case of failure of an initial wash, prosthetic material must be removed and a hip transposition procedure should be preferred to a second-look surgery. Concerning prophylactic antibiotherapy, a dual therapy for at least 48 h after surgery should probably be preferred.

Critical study of resection margins in adult soft-tissue sarcoma surgery.

INTRODUCTION: Resection margins constitute a recognized risk factor for local recurrence, but their impact on survival is less clear. HYPOTHESIS: Infiltrative proliferation and satellite nodules are prognostic factors for local and systemic aggressiveness. TYPE OF STUDY: Retrospective cohort study. PATIENTS AND METHODS: In 105 patients under curative treatment, resection quality was assessed on UICC criteria (R0/R1) and on a modified version (R0M/R1M) taking account of proliferation contours and satellite nodules for narrow margins (<1mm). Uni- and multi-variate analysis was performed, and Kaplan-Meier survival curves were compared on log-rank. RESULTS: Mean 5-year local recurrence-free survival (LRFS) was 0.64 [0.52-0.76] after R1 surgery, 0.9 [0.85-0.95] after R0, 0.64 [0.519-0.751] after R1M and 0.92 [0.87-0.96] after R0M. Resection type according to R classification correlated with disease-free survival (DFS) (P=0.028), but not with metastasis-free survival (MFS) (P=0.156). Resection type according to RM classification correlated with DFS and MFS. Multivariate analysis disclosed correlations between LRFS rate and RM resection type (HR 6.77 [1.78-25.7], P=0.005), DFS rate and RM resection type (HR 2.83 [1.47-5.43], P=0.001) and grade (HR=3.17 [1.38-7.27], P=0.003), and MFS and grade (HR=3.96 [1.50-10.5], P=0.006). DISCUSSION: The microscopic aspect of the proliferation contours and presence of satellite nodules were confirmed as prognostic factors for local and systemic aggressiveness. They impact both disease-free survival and metastasis-free survival in case of margins less than 1mm. Their systematic consideration may help identify patients with elevated systemic risk. LEVEL OF EVIDENCE: IV.

Open wedge high tibial osteotomies: Calcium-phosphate ceramic spacer versus autologous bonegraft.

INTRODUCTION: Valgus tibial osteotomy (VTO) is a well-known procedure for the treatment of medial compartment femoro-tibial osteoarthritis. Good and very good results have been reported with calcium phosphate wedges, which avoid the inconveniences of autologous grafts use. The hypothesis of this study is that with equivalent results in the treatment of osteoarthritis of the knee, the use of calcium phosphate wedges (BMCaPh) to fill the bone defect created by osteotomy would result in fewer specific complications and less pain associated with autologous grafts (AUTO) harvesting. PATIENTS AND METHODS: This prospective, controlled, randomised study included one arm that received a macroporous, biphasic calcium phosphate wedge (BMCaPh group) and one arm that received an autologous tricortical graft (AUTO group) for filling. The same plate with locked screws was used for fixation in all cases. All patients underwent at least two years of clinical and radiographic post-operative follow-up. RESULTS: Forty patients were included. Loss of correction occurred in six of the twenty-two patients in the BMCaPh group (27%), resulting in three early surgical revisions, compared to one loss of correction in the AUTO group. Lateral cortical hinge tears were a risk factor for loss of correction for the entire cohort and in the BMCaPh group. (relative risk 13.3 [1.9-92]. Moreover, union took significantly longer and pain lasted significantly longer in the BMCaPh group, although results were comparable at 6 months. DISCUSSION: A significant number of undesirable events (loss of correction) occurred in this study, limiting the number of included patients. Nevertheless, the results show that although there was no difference in the two groups for overall complications, number of revisions all causes combined, or clinical results, filling with BMCaPh was less tolerated and increased the risk of loss of correction when local mechanical conditions of the knee were unfavourable (lateral cortical hinge tears). Moreover, although it is not possible to draw a conclusion because of methodology bias in this study, early weight-bearing resumption on the knee also seemed to favour these complications. LEVEL OF EVIDENCE: Level II. Prospective randomized study.

Dual mobility design use in preventing total hip replacement dislocation following tumor resection.

INTRODUCTION: Total hip replacement (THR) following hip tumor resection incurs a high risk of dislocation. We assessed the incidence of dislocation associated with use of a dual mobility cup,and the functional results achieved. HYPOTHESIS: Use of a dual mobility cup would reduce the risk of THR instability following hip tumor resection. MATERIAL AND METHODS: We analyzed dislocation rates in a retrospective series of 71 dual mobility cup THRs implanted following the resection of a tumor hip condition: 33 primary bone tumors and 38 bone metastases. The presenting pathology was diagnosed anatomically, and surgery classified in terms of adopted abductor system strategy. Functional results were assessed in terms of pain (analgesia on the World Health Organisation [WHO] scale), assisted walking and Musculoskeletal Tumor Society (MSTS) score. RESULTS: An overall rate of 9.8% dislocation was observed, taking into account all etiologies and contexts together. More precisely, this rate resulted from a compound figure of 5.2% in bone metastasis and 15% in primitive bone tumor. Dislocation risk depended lesson etiology than on the surgical management of the abductor system, being 3.5% in the case of abductor conservation, 9.5% in the case of abductor sectioning/reinsertion, and 18%in case of gluteus medius muscle or nerve resection. Functional improvement was consistently observed, especially in bone metastasis. At the maximal follow-up, 32 patients were not using analgesics, six were taking WHO class III analgesics, 10 class II and 23 class I. Mean MSTS score was 68.1% +/- 23.5% in bone metastasis and 59.6% +/- 17.5% in primary bone tumor.Fourteen patients could walk without assistance, 33 with a single cane, 15 with two canes and eight with a walker; one patient had not been able to resume walking. DISCUSSION: In these indications, dual mobility cups use lead to lower dislocation rates than those reported in the literature. It proved especially effective in the case of bone metastasis and consolidation surgery. In the case of primary bone tumor, it failed to prevent dislocation following acetabular resection, especially when involving the abductor muscles and/or abductor innervation, although it provided lower dislocation rates, comparable to those experienced with other techniques, when applied to limited resection. LEVEL OF EVIDENCE: IV. Retrospective therapeutic study.

Long bones giant cells tumors: treatment by curretage and cavity filling cementation.

OBJECTIVE: Giant cell tumors (GCT) of bone are benign tumors with local aggressiveness that most of the time occur around the metaphyseal area of long bones, often in contact with the articular cartilage. Their treatment remains controversial because of their high recurrence rate. The authors report a retrospective series of 30 cases treated using curettage followed by cementation. They suggest demonstrating the mechanical and functional benefit of this technique, its benefit controlling the risk of recurrence, and of osteoarthritis potential. MATERIAL AND METHODS: Between 1992 and 2005, 30 patients with GCT were treated using curettage and cementation. Twenty-six of these tumors were present around the knee: 14 at the distal femur and 12 at the proximal tibia. Preoperative radiological evaluation with standard X-rays showed that the tumor measured a mean 71x45mm, for a mean volume of 78cm(3). Seventy-three percent of these GCT were in direct contact with the articular cartilage and 40% extended to the soft tissues as seen on the CAT scan and/or MRI. All patients were treated with curettage and cementation, 16 additional internal fixation procedures were performed. The mean follow-up of this series was 6 years and 4 months. All patients continue to be monitored, with none lost to follow-up. RESULTS: In all our cases, nine recurrences (30%) were observed during the first 2 years. Six patients were treated with a new curettage and cementation procedure and three underwent a total knee arthroplasty. None of these lesions had recurred at the last follow-up. The MSTS score, reflecting the function of the operated limb was a mean 93.33% (28 + or - 2/30). Standard radiological assessment showed a thin scalable border on four patients and was normal for the all-total arthroplasty cases. Two cases of minor osteoarthritis progression were noted (one less than 50% and a simple densification of subchondral bone), requiring no specific treatment. Three complications were noted: one leg deep venous thrombosis, one hematoma, and one deep infection without impacting the initial treatment outcome over the long term. DISCUSSION: The curettage and cementation technique is usual practice in GCT treatment. Simple and reproducible, this technique has a lower rate of complication than other treatment options such as cryotherapy. It produces a lower rate of recurrence with the dual benefit of excellent mechanical and functional qualities. Diagnosis of recurrence can be made earlier because of the thin scalable border at the bone-cement interface. This technique does not generally cause osteoarthritis, which was found in only two cases with no evidence of the cement having a direct effect. The 30% recurrence rate observed in this series shows that the benefit provided by the cement as an adjuvant preservative remains modest. CONCLUSION: The cement mechanical and cytotoxic properties as well as its innocuity and its ease of handling make curettage and cementation one of the top-ranking GCT treatment options. An even lower rate of recurrence may be obtained through development of additional adjuvant treatments such as calcitonin and bisphosphonates. LEVEL OF EVIDENCE: Level IV; Therapeutic study.

[Pertrochanteric fractures in elderly subjects aged over 75]. / Les fractures du massif trochantérien chez les sujets âgés de plus de 75 ans.

Pertrochanteric fractures constitute a major public health concern. This retrospective multicentric study evaluated outcome after treatment in patients aged over 75 years hospitalized for pertrochanteric fractures over a one year period (May 2004-May 2005). Five University Hospitals in the cities of Angers, Brest, Rennes, Tours, Nantes participated in this evaluation. The quality of the reduction and the position of the osteosynthesis were the two main criteria for good outcome. The type of material implanted had little effect on outcome. The results emphasized the importance of preventing osteoporosis. Fracture prevention and treatment of osteoporosis are crucial, even after fracture.

[The serratus anterior free flap in limb reconstruction. About 30 cases]. / Le lambeau de serratus anterior en chirurgie reconstructrice du membre inférieur. A propos de 30 cas.

Between 2001 and 2003, 30 serratus anterior free flaps have been realized in our unit for reconstruction of lower limb. The flaps were indicated for repair of traumatic soft tissue defect in 19 cases, for chronic wound in six cases, for purpura fulminans in two cases, for pressure sore in one case and after tumor resection in 1 case. There were 29 patients: 25 males and four females. They ranged in age from 5 to 64 years. The size of the soft tissue defects ranged between 15 and 180 cm(2). Four different types of serratus anterior flaps were used: 20 muscle flaps ; four myocutaneous flaps ; five costo-osteomuscular flap ; one costo-osteomyocutaneous flap . In all cases we used osteo flap (8 th rib) in order to restore bone defect, which ranged from 9 to 15 cm. Necrosis occurred in two flaps because of venous thrombosis. The functional outcome was good for all patients and the aesthetic sequelae at the donor site were considered as minor. The serratus anterior flap can be used in many different ways: different kinds of flaps (osteo-cutaneous-muscle); very variable size of flap (15 to 180 cm(2) in our series) , different length of pedicle possible. Because of his versatility and his absence of major functional or aesthetic sequelae the serratus anterior free flap has become day by day our favourite option in limb reconstruction.