Introduction

Bi-compartmental knee arthroplasty (BKA) is an alternative to total knee arthroplasty (TKA) for degenerative joint disease when present in only two compartments. BKA spares the cruciate ligaments and preserves bone in the healthy compartment, possibly leading to better knee kinematics and clinical outcomes when compared to TKA. While BKA is a technically demanding procedure when performed with manual instrumentation, robotic assistance allows for accurate implant placement and soft tissue balancing of the joint. Robotic unicompartmental knee arthroplasty (UKA) has shown favourable clinical outcomes and survivorship at short term (2 year) follow up compared to manual UKA. The purpose of this study is to evaluate the short term functional outcomes and survivorship of patients undergoing robotically assisted BKA.

INTRODUCTION

Bicompartmental knee arthroplasty (BKA) is an alternative to total knee arthroplasty (TKA) for degenerative joint disease when present in only two compartments. BKA spares the cruciate ligaments and preserves bone in the healthy compartment, possibly leading to better knee kinematics and clinical outcomes when compared to TKA. While BKA is a technically demanding procedure when performed with manual instrumentation, robotic assistance allows for accurate implant placement and soft tissue balancing of the joint. Robotic unicompartmental knee arthroplasty (UKA) has shown favorable clinical outcomes and survivorship at short term (2 year) follow up compared to manual UKA. The purpose of this study is to evaluate the short term functional outcomes and survivorship of patients undergoing robotically assisted BKA.

The purpose of the study was to compare prospectively and randomly two ACL reconstruction single bundle techniques, one referred to as traditional and the other referred to as anatomical, where the coronal angulation of the femoral tunnel aimed a more horizontal position at 2 and 10 o'clock. Orthopilot® System (Aesculap, Tuttlingen, Germany) was used to assist tunnel positioning in order to obtain and register translational and rotational stability.

Eighteen patients (14 men and 4 women), average age 33.8 years (range 18 to 49), with isolated ACL lesion were randomized in two groups, A (Conventional) and B (Anatomical). All patients were submitted to ACL navigated arthroscopic reconstruction with quadruple hamstrings grafts. Anteromedial portal access for femoral tunnel drilling was used in all patients. The tibial and femoral tunnels drillings were monitored by the Aesculap® Orthopilot Navigation System. In Group A, the femoral tunnel positioning aimed isometricity. In Group B, femoral tunnel was drilled at 25% of Blumensaat's line length from the posterior cortex, and 30° orientation in coronal plane. Initial and final Maximum Anterior tibial Displacement (MATD), Internal Tibial Rotation (ITR) and External Tibial Rotation (ETR) at 30° knee flexion data were recorded intra operatively by the navigation system.

No horizontal or rotational stability differences were found for MATD (p = 0.68), ITR (p = 014) and ETR (0.13). This study did not support the hypothesis that a more anatomical positioning leads to better rotational or anterior stability.

Purpose: The objective of this study was to analyze and compare the results obtained after 2 types of treatment, surgical and conservative, for acute patellar dislocations.

Methods: We divided 33 patients with acute patellar dislocations into 2 groups. One group with 16 patients underwent conservative treatment (immobilization and subsequent physiotherapy), and the other group with 17 patients underwent surgical treatment. A radiographic examination was performed in the evaluation of the patients to verify predisposing factors for patellofemoral instability, and the Kujala questionnaire was applied with the intention of analyzing the improvement of pain and quality of life. The 2 test, t test, and Fisher test were used in the statistical evaluation. A significance level of P.05 was adopted.

Results: The groups were considered parametric in relation to age and sex. The conservative treatment group exhibited a higher number of recurrent dislocations (8 patients) than the surgical treatment group, which did not have any relapses. In addition, the surgical treatment group obtained a better mean score on the Kujala test (92) than the conservative treatment group (69).

Conclusions: We conclude that surgical treatment afforded better results. There were no recurrences in the surgical treatment group, but there were 8 recurrences in the conservative treatment group. The mean Kujala score was 92 in the surgical treatment group and 69 in the conservative treatment group. Level of Evidence: Level II, lesser-quality therapeutic randomized controlled trial. Key Words: Patellofemoral— Dislocation—Recurrences—Medial patellofemoral ligament—Knee.

Introduction: Papers about high-virulence infections are not usual, results contradictory, and orthopaedic outcomes not described.

Purpose: to compare infectious and orthopaedic results after late arthroplasty infections by single vs. polymicrobial isolates, low vs. high-virulence, and Gram-positive vs. Gram-negative organisms, when treated by exchange surgery plus long cycles of combined oral antibiotics.

Patients and Methods: A late arthroplasty infection was diagnosed in 68 consecutive patients (48 female) of 72.2(+/−10.2) years (37 hips/31 knees).

Cultures were polymicrobial in 22 cases and by Gram-positive in 55 (80.9%). Highly-resistant organisms: methicillin-resistant Staphylococcus (36 patients) and ESBL-producing Enterobacteriaceae (2 patients). “Problematic-treatment”: Enterococcus (6 patients), Pseudomonas (3 patients), non-fermenting Gram-negative (2), moulds (1).

Oral antibiotic selection: according to bacterial sensitivity, biofilm and intracellular effectiveness. Protocolized surgery: two-stage exchange. Average follow-up: 4.7+/−2.7 years (1–11).

Healing of infection is diagnosed if absence of clinical, serological and radiological signs of infection during the whole follow-up. Orthopaedic outcome is evaluated by HHS for hips and by KSCRS for knees.

Results: Surgery was not possible in 7 infections (rejected by patients), and reimplantation in 17 additional cases (patients died shortly after first surgery, rejected 2nd surgery, or was contraindicated because of medical reasons).

Healing of infection: 59/68 patients (86.8%), 32/37 hips (86.5%) and 27/31 knees (87.1%). Infection not healed: 7/68 cases (10.3%) (4/37 hips, 3/31 knees) (5 by highly-resistant and 1 by “problematic-treatment” bacteria). There are no differences between hips and knees (p=0.55).

Orthopaedic Results: HHS averages 80.5+/−16.2 (81+/−16 in healed infection, 56+/−23.5 in persistent infection). KSCRS averages 77.2/58.1 +/− 19.8/24.5 in healed infections, 32.6/0+/−25.8/0 in persistent infections. Infective and orthopaedic results present a strong statistical correlation in hips (p=0.016) and knees (p=0.0001).

Statistically significant differences are not found when comparing subgroups according to Gram stain (p=0.43), multiple vs single bacteria (p=0.47 infective, p=0.71 orthopaedic), highly-resistant bacteria (p=0.2 infective, p=0.1/0.5 orthopaedic), or “problematic-treatment” (p=0.68).

Conclusions:

A strong statistical correlation appears between infective and orthopedic results after late arthroplasty infections.

Introduction: Influence of beta-blockers against fracture is controversial. Role of beta-blockers in fracture treatment not explored.

Objective: to analyze influence of propranolol, a beta-blocker, on fracture healing in a mouse model.

Materials and Methods: Fracture and intramedullary nailing on right femur of 8 week, male C57BL/6 mice. Daily propranolol in drinking water: 0 (control), 4 (low dose) and 20 (high dose) mg/kg 3 week: microcomputed tomography (microCT), histological analyses 6 week: microCT, mechanical testing N = 5 üC 9/group Statistics: two-way ANOVA. Á = 0.05.

Results: From 3 to 6 weeks, callus volume and bone mineral content (BMC) decreased, and tissue mineral density increased significantly in control groups. Callus volume and BMC decreased significantly in low dose groups. No significance in high dose groups. No significance with treatment. At 3 weeks, callus area and woven bone percentage not different with treatment. At 6 weeks, ultimate torque not different with treatment or fracture. Within the control groups, twist at ultimate torque significantly lower in fractured bones. Torsional rigidity increased significantly in fractured bones, but not different with treatment.

Discussion: Most studies based on population observation or manipulation of sympathetic signaling using intact animal bones. The current fracture model may have created neural damage, thereby interrupting the sympathetic pathway and negating its regulation of bone metabolism. Whether neural signaling is compromised by fracture treatment requires further study and may be critical to the action of beta-blockers in bone.

Introduction: Fusion of the knee joint should be the last option for salvage of infected total knee arthroplasty (TKA). Although knee arthrodesis implies lost of function, it is a successful treatment in eradicating the infection and in decreasing pain.

External fixation compression devices have been an excellent method for gaining fusion but, there is no documentation about its ability for obtaining adequate limb alignment with a stable fusion of the knee joint.

Material and Methods: We have retrospectively reviewed the results of knee arthrodesis after infection of TKA using an anteriorly placed unilateral external fixator. In addition, we have assessed patient self-satisfaction.

Postoperative radiographs have been evaluated to digitally measure loss of femoral and tibial bone stock using Engh radiological classification. Moreover, we have quantified tibiofemoral alignment and the section of bony fusion. Fusion of the knee joint was assessed with CT. Patients were interviewed and pain was graded using a Visual Analog Scale (VAS) and self-satisfaction as well as current health status using the 12-item social function survey form (SF12).

Results: From 1992 to 2003, 52 arthrodeses were done for treatment of infected TKA. The average age was 71 years (range, 37–83 years). Type III bone defect according with Engh classification, in femur and/or in tibia, was present in 50% of the patients. The average postoperative tibiofemoral alignment was 1.2° (SD 3.79). The mean time to fusion was 11.26 months (range, 3–30 months). Time to fusion was statistical related with severe bone loss and with the tibiofemoral contact section. The average score according VAS was 1.6 (SD 2.60).

Conclusions: Knee arthrodesis using a monolateral external fixator for infected TKA is an effective method to control infection as well as to obtain knee fusion and pain relief. Severe bone loss, frequently present in infected TKA, was found to be the most relevant factor in achieving tibiofemoral union. The individual clinical result according to SF12 shows a lower quality of life both for physical and mental components compare with general population.