Patient specific instrumentation (PSI) for total knee arthroplasty (TKA) may improve component position and sizing. However, little has been reported about the accuracy of the default plan created by the manufacturer. The purpose of the study was to evaluate the reliability of the manufacturer plan and the impact of surgeon's changes on the final accuracy of the cutting guide sizes.

The planned sizes of 45 TKAs were prospectively recorded from the in the initial manufacturer's proposal and from the final plan modified after surgeon's evaluation and compared to the actually implanted sizes.

The manufacturer's initial proposal differed from the final implant in 20% of the femoral and 51.11% of the tibial components, while the surgeon's plan in 13.33% of the femoral and 26.67% of the tibial components. Surgeon's modifications in the pre-operative were carried out for 11.11% of the femoral components and 51.11% of the tibial ones (p = 0.0299). Appropriate modification occurred in of 88% and 76% of femoral and tibial changes respectively.

The surgeon's accuracy to predict the final component size was significantly different from that of the manufacturer and changes on the manufacturer's plan were necessary to get an accurate preoperative plan of the implant sizes. Careful evaluation by an experienced knee surgeon is mandatory when planning TKA with PSI. Collaboration between surgeons and manufacturers may help obtain improved accuracy in PSI size planning.

Introduction

The dual mobility cup was introduced in the 1970s to allow extensive range of motion associated with great stability thanks to double articulation; the first between the head and polyethylene, the second between the polyethylene and the cup.

The original plan was to install a stainless-steel uncemented cup coated with a thin layer of alumina and a metal head of 22,2 mm with a polyethylene liner of first generation.

Long term follow-up case studies are cited in the literature showing excellent results in reducing dislocations; however wearing and aseptic loosening are noted.

The new dual-mobility cups, with reticular polyethylene and titanium and hydroxyapatite coating are proving as reliable as the older ones in terms of stability whilst they appear to be more durable.

Furthermore, cemented dual-mobility cups are available, these are the topic of this study. One of the most frequent complications in the major revisions of hip replacement is dislocation. This study summarises our experience gathered in the use of dual-mobility cups during revisions of complex cases (GIR III-IV femoral or acetabular).

Introduction

Periprosthetic joint infection (PJI) is considered one of the most feared causes of implant failure, due to the difficulty in formulating a proper and timely diagnosis. In the diagnostic workup are often used test with a low specificity, such as the dosage of ESR and CRP, or sensitivity, such as cultures or the leukocyte count of the synovial fluid. Radiological investigations are expensive and unreliable to play a direct role in the diagnosis of PJI. The alpha-defensin is an antimicrobial peptide released by neutrophils in response to pathogens and it is an ideal biomarker for the diagnosis of PJI. It is now possible to verify the presence of alpha-defensin in periprosthetic synovial fluid with an ELISA (Synovasure® PJI, Zimmer) that provides results in 10 minutes, with a sensitivity of 97% and a specificity of 96%, without being affected by systemic inflammatory diseases or by the assumption of antibiotics. The purpose of this study is to assess the applicability and reliability of Synovasure® PJI, correlating its results with microbiological analyzes, laboratory tests and imaging studies of the patient.

Dislocation is the most relevant early complication after primary total hip replacement (THR) in literature. Many factors have been advocated for dislocation, either surgeon-related either patient-related. Component positioning seems to be of major importance in determining dislocation. We evaluated 152 randomised THR with a CT study between 985 THR done at our Institute since november 2004 to november 2006.

152 randomised primary THR on a total of 985. The same prosthetic pattern (head size, stem, cup). Lateral approach with total capsulectomy and external rotator tendon resection. All 152 patients underwent a post operative standardized CT study assessing cup antiverion and inclination angles and stem antiversion angle. Dislocated patients where furthermore analysed for any detail concerning their procedure and follow-up. A safe zone was then deduced for safer positioning.

During the follow-up period dislocation occurred in 5 hips (only one in the randomised group) assessing our rate of dislocation at 0.5%. All dislocation were managed with closed reduction and an articulated hip brace. No open reduction or revision surgery were further needed. The mean cup abduction was 47° in the dislocated hips and 49° in the control group. Mean cup anteversion was 29° in both groups. The mean stem anteversion was 8.2° in the dislocated group and 3.1° in the control group. No statistical difference could be reached between dislocation and cup positioning. A correlation between hip dyspalsia (Crowe II) as primitive diagnosis and dislocation could be reached considering all the THR procedures.

In THR inappropriate cup and stem positioning is considered an important risk factor of postoperative dislocation. Accurate and reproducible measurement is mandatory for implant positioning evaluation. Conventional radiographs cannot provide accurate and reproducible measurement. CT can provide a precise measurement of prosthetic components. Several studies failed to demonstrate a correlation between component positioning and dislocation often because of small number of patients and many bias. We tried to reduce bias using the same prosthetic pattern and the same surgical approach. Notwithstanding we could not reach a statistical difference in term of prosthetic positioning between dislocated and control group. Perhaps the dislocated group was too small to have a statistical meaning. We could determine a Safe Zone of cup and stem positioning for our patients: cup anteversion between 24° and 33°, cup inclination between 42° and 50°, stem anteversion between −3° and 10°.

Dislocation is the main early complication after THR. Its etiology depends on many factors. Sometimes the cause can’t be identified. Orientation of prosthetic components may be responsable for dislocation but its truly correlation can be hard to be assessed. In this study we found no correlation between implant positioning and occurrence of dislocation, but we defined a tighter Safe Zone than previous reported, in which the risk of dislocation is nought. A correlation between hip dyspalsia (Crowe II) as primitive diagnosis and dislocation could be reached.

Metal on Metal coupling in total hip replacement has been widely used since many years. After the rebirth of resurfacing a new trend to use very large diameter metal-metal coupling with standard stem prostheses has been started. New prostheses, old and new problems. We analyze first failures with new large diameter metal on metal coupling.

The analysis focused on seven early failures of large diameter metal-metal prostheses (two resurfacing and five cementless prosthesis with XL head) over the first series of 350 cases (100 resurfacing and 250 cementless) in the first year. Synovial fluid aspiration have been performed in all failed patients searching for metal ions and bacterial proliferation. Moreover, prosthetic component positioning was also studied as a possible primum movens of these failures. Some failed patients underwent epicutaneous patch test for skin reaction to metal.

One resurface prosthesis failed as a result of an vascular necrosis and conseguent fracture of the femoral neck and revealed a moderate increment in metal ion concentration in blood and synovial fluid obtained at time of revision.

One resurface prosthesis failed as a result of an infected metallosis with a huge intraabdominal mass and revealed a huge increment in metal ion concentration in blood, addominal and synovial fluid. This patient underwent a lumbotomy to evacuate the abdominal retroperitoenal mass before prosthesis removal for a two step procedure.

Out of the five failures of metal on metal cementless prosthesis with XL head four were the result of aseptic loosening and one was the result of a low grade infection discovered at coltures after revision surgery. Three showed clear metallosis caused by wrong positioning (more than 50° of cup inclination). All of these three presented an articular noise and elevated blood and sinovial fluid metal ion concentration. The fourth patient with aseptic loosening had a good component positioning but demonstrated an epicutanous allergic reaction to Cobalt. Also one of the three patients with metallosis resulted allergic to Cobalt. The blood and sinovial metal ion values were always elevated but particularly high in patients with cup inclination over 50°.

Large head metal on metal prostheses demonstrated a higher percentage of early failure in our experience. They are very sensible to positioning. Blood and sinovial metal ion determination helps to promptly diagnose a bad metal on metal prosthetic functioning. A more accurate analysis about the different metals available on the market and their resistance to edge wear should not be delayed any further.

Aims: Healing of the rotator cuff after surgical repair continues to be one of the most challenging areas of shoulder surgery. Autologous Platelet Derived Grow Factors (PDGF) have been shown to positively affect the tissue healing, but their effect have not been studied in relation to tendon healing. The purpose of this study is to evaluate if the use of PDGF in rotator cuff surgery could lead to a better and faster healing of the repair.

Materials e Methods: We treated two groups (A,B) of 14 shoulders in 14 patients (mean age 66 and 63.4) with a full thickness rotator cuff tear. The group A and B were treated with a full arthroscopic repair of the cuff. In the group A, at the end of the procedure, the PDGF have been injected at the level of the lesion, between the tendon and the bone and over the tendon repair without irrigation and after the removal of all the cannulas. The group B, repaired in the same fashion, without PDGF, has been used as control.

In the group A the patients had an accelerated postop. rehabilitation. The group B received a standard rehabilitation protocol. Each group has been evaluated prospectively with VAS, UCLA and Constant scores pre-op and during follow-up.

Results: Both group showed an increase of the scores, compared to the pre-op. value (tab.1).

The VAS score of group A (PDGF) was pre-op. 5.6 and at 1 year 1.4. The VAS score of group B (no PDGF) was pre-op. 5.2 and at 1 year 1.4. The UCLA score of group A was pre-op. 16 and at 1 year 33.8. The UCLA score of group B was pre-op. 16.7 and at 1 year 32.9. The Constant score of group A was pre-op. 53 and at 1 year 90.7. The Constant score of group B was pre-op. 54.2 and at 1 year 90.1.

The complete statistical analysis of the data showed no significant differences in the results of the two groups (p< 0,01), with every kind of scores, VAS, UCLA and Constant, at the final follow-up of 1 year.

Conclusions: Our data suggest that the use of PDGF, compared to a standard repair, does not affect the quality of the rotator cuff repair at 1 year. Moreover the study suggest that the use of PDGF allows an accelerated rehabilitation program with ten days of immobilization compared to four weeks as usually prescribed. Further studies should clarify the real effect of PDGF about the acceleration of the first phase of the cuff healing.

Aims: Traditionally in surgery, and this is especially true in orthopaedic foot surgery, is not paid much attention to patient’s emotions, not considering how specific personality traits could affect pre and post surgical management. Following the guidelines of WHO about the treatment of pain and in order to optimize the clinical management of patients who complain of painful foot disorders such as hallux valgus, we studied the relation between level of anxiety, perception of pain and memory pain before and after the surgical procedure.

Methods: In the period 2000 and 2004 we studied 88 patients who were treated with distal metatarsal osteotomy for correction of hallux valgus. In order to evaluate anxiety trait level we selected one of the most frequently employed tests in clinical medicine (S.T.A.I. Y2). To quantify the amount of pain, due to such pathology in the pre and post surgical period, FFI test (visual analogous) and a questionnaire on pain memory, were employed. Pain was studied longitudinally, in the following steps: presurgery, immediately postsurgery, daily in the first four days, and at one and two weeks interval after the procedure. The use of analgesic drugs in the first two weeks was recorded. Two years later the same patient were recalled in order to collect data related to the clinical outcome and pain memory persistence.

Results: A subgroup of 33 patients showed an high anxiety trait level (score > 43), the remaining 50 patients had a score in the normal range.

The statistical analysis of the data shows a direct correlation between anxiety level and pain perception in the pre surgical period. Furthermore, patients with higher level of anxiety showed an increased use of analgesic drugs in the post surgical period (the higher dosage prescribed on demand). The unpleasant memory persistence is however mitigated in the same group, possibly due to much drug assumption.

Conclusions: A correct management of patients with painful diseases candidated to surgical procedures should include a comprehensive psychological evaluation in order to identify their emotional state. Especially in clinical situations requiring bilateral surgical approaches is mandatory to avoid that pain could become a traumatic experience.

Total Hip Replacement (THR) in proximal, posterior iliac dislocation of the hip often represents a problematic issue. Reviewing their selected cases (70 patients between 3700 THR from 1986 to 2001), authors focalized some key points for this demanding surgery. The most important steps are acetabular positioning, implant decisioning and surgical approach (exposure and release).

Acetabular cup positioning. The natural site (Paleoacetabulum), the ideal place to restore biomechanical and dynamic properties of the joint, many times gives few chances to achieve primary stability. So one site, at least the nearest possible to the natural site must be reached. A CT or MRI study is necessary to assess preoperative planning for cup positioning. We used two different cups, the Zweymuller and the Wagner cup, with good primary stability. A Conus stem (Wagner) or an Alloclassic stem (in less displastic femoral shape) was used.

We always performed this surgery as a one step procedure. No preventing traction or release surgery was performed. An anatomic and wide (medial and lateral) exposure of the joint must be performed. We used the Smith-Petersen approach modified by Wagner. A meticulous periarticular release of soft tissue was performed. In same cases a shortening femoral osteotomy was performed to allow refractory reduction. Possible complications are discussed. Good clinical outcomes at more than ten years are shown.