Aim

The demonstration of the in vivo bactericidal efficacy of a new bone cement with rifampicin contained in microcapsules and its intra-articular release profile.

35 patients with an infected total knee arthroplasty were operated with a two-stage revision protocol including the use of custom hand-made antibiotic loaded articulating spacers.

Spacers were built intraoperatively, without specific tools, regarless the defect being considered cavitary or segmentary.

Patients were allowed to walk with an orthosis. Range of motion (ROM) with the articulating spacer averaged 80° and after reimplantation 106.5°. All but two patients in our series were treated with a combination of antibiotics including rifampicin and the antibiotics used in the spacers constituted from 7.5% of its final weight.

Reimplantation was successfully performed in 33 out of 35 cases at an average time of 10.2 weeks, excluding a patient were we had to wait 2.5 years. An extended exposure at reimplantation was necessary in 21% of the patients (five “Q-snip” and two anterior tibial tuberosity osteotomies).

According to the Knee Society Score (KSS) the results were considered excellent or good in 27 patients (84.8%), and fair or poor in 6 patients (14.2%) out of the 33 reimplantated. No significant differences related to the micro-organism or the time elapsed until reimplantation, as compared for ROM and functional and clinical KSS were found but early infections had significant worst ROM than late or sub-acute infections. Intercondylar constrained designs had better functional, clinic KSS and ROM that posterostabilised designs or hinge designs without significant differences.

Our modified technique for custom made spacers can be applied in any surgical theatre with a minimum cost. Our results are comparable to those reported in the literature, demonstrating the consistency of the two-stage reimplantation protocol despite multiple modifications and different dosages of antibiotic used in the cement spacers.

Objective: Exogenous hyaluronic acid (HA) acts as a lubricant and shock absorber, and is considered to have many other beneficial effects in the joint. Several studies have shown that HA is able to provide pain relief and promote the synthesis of endogenous HA and protect the cartilage and synovia by covering joint surfaces. The objective of this study is to investigate wheter an isotonic solution of hyaluronan reduces post-arthroscopic symptoms in the knee such as joint pain, swelling and impairment of function when injected into the joint following arthroscopic surgery.

Material and Methods: A total of 93 patients (66 men, 27 women) were assessed in a multicentre, controlled study conducted by several investigators from different orthopedic surgery departments in Spain. All investigators were highly skilled in arthroscopy. Patients were allocated into two groups, control group (45 patients) or treatment group (48 patients). The treatment group received an injection of 10ml of isotonyc solution of hyaluronan (ISH) 0.5% with a physiological pH value at the end of the knee arthroscopy after final lavage with normal irrigating solution. Untreated patients underwent standard arthroscopic surgery (meniscectomy or articular lavage) and did not receive any further treatment on completion of the procedure. Pain in patientes were assessed using a 100mm visual analog scale (VAS). Between-group comparative analyses were performed before surgery and 1 and 4 weeks after surgery using a Mann-Whitney U-test.

Results: One week after surgery, a significant reduction in pain (up to 17%) was observed for patientes treated versus control patients (p< 0.01). This improvement was maintained until week 4, although the difference between control group and treated group decreased over time. The area under the curve of VAS was 39% lower for treated patients versus untreated patients. On comparing both groups, there was a significant 8% difference in the reduction of other functional symptoms at 1 week after surgery but no difference at 4 weeks after surgery. No adverse events were reported.

Conclusions: The results show that there were was a significant decrease in pain in the first week after surgery, accompanied by a significant reduction in sum of symptom scores. These results suggest that ISH accelerates post-arthroscopy recovery during this important period by reducing pain and discomfort, and increasing the mobility of the affected knee.

Introduction and purpose: Two-stage reimplantation of a hip replacement is the treatment of choice for deep periprosthetic infections. The purpose of this study is to analyse the survival of the femoral component in two-stage hip replacement reimplantations and compare the results of cemented and cementless components.

Materials and methods: Between 1988 and 1998 our hospital carried out 169 two-stage reimplantations for treatment of first episodes of deep infection. The femoral component was cemented in 121 cases and cementless in 48. All patients were followed up clinically and radiologically for at least five years.

Results: The two-stage revision was associated with a significant clinical improvement. The reinfection rate was 9% (16/169), of which 11 patients underwent revision surgery and five received chronic suppressive antibiotic treatment. Eight patients required revision due to aseptic loosening and two for periprosthetic fracture. With the numbers available, fixation with or without cement showed no significant differences.

Conclusions: The two-stage revision of an infected hip prosthesis resolved the infection in 91% of the cases. An additional 5% required revision due to aseptic loosening. The surgical outcomes seem to be independent of the femoral component fixation (cemented or cementless).

Introduction: Osteoarthritis is the most common joint disease in the world. Biochemical and genetic factors as well as mechanical stress contribute to lesions in the cartilage. The present study analyses the effect of b-Endorphin on the cells of articular cartilage.

Materials and methods: We used rat articular cartilage for the study. After tripsinizing the cartilage and isolating the chondrocytes the cells were cultured in a culture medium. B-Endorphin was dissolved in the culture medium at concentrations of 1 and 10 mM. Only the culture medium was added to the control wells. Naloxone 1 mM was added for co-treatment with b-Endorphin and naloxone. Thirty minutes later, b-Endorphin was added, thus blocking its receptors.

Results: We studied the effect of this procedure on chondrocytes’ proliferating activity and on the proteoglycan synthesis of the extracellular matrix. An increase was observed in the incorporation of 3H-Thymidine, which in turn reflected an increase in the chondrocytes’ proliferating activity. In addition, 35S incorporation analyses were made of cultures which assessed proteoglycan synthesis which showed an increase in the extracellular-matrix forming activity. Differences between the groups with b-endorphin, b-endorphin + naloxone and the control group were found to be highly significant (p< 0.01).

Conclusions: B-endorphin has a stimulating effect upon chondrocytes and proteoglycans present in the extracellular matrix in culture. These stimulating effects are mediated by the interaction with a specific opioid receptor, present in the articular cartilage cells. It may be conceived that trophic stimulation of cartilage cells in the early stages of the disease might partly mitigate the loss of joint surface.

Introduction and Objectives: The increase in hip replacement surgery in recent years as a consequence of the aging population and a greater demand placed on joints by our current lifestyle has caused an increase in related complications. The rate of intraoperative periprosthetic fractures is between 0.8 and 2.3%, and postoperative fracture rates reach 0.1% in some studies. This type of fracture is usually complex, and treatment is almost always quite difficult.

Materials and Methods: This study concentrates on peri-prosthetic hip fracture as a postoperative complication examining cases treated during the last 5 years. We have included cases of cemented and cementless partial and total arthroplasty. In this study, we did not include intra-operative fractures (secondary to surgical manipulation, as a result of reaming, cementing, or impaction of prosthetic components) because an irregular clinical history was associated with such cases, only reflecting those which required some type of synthesis, particularly cer-clage. The Johanson scale and the AAOS classification were used to classify fractures.

Results: Of 30 periprosthetic fractures recorded during the study period, 11 patients (36.7%) were males and 63.3% were female. Of fractures of the femoral diaphysis, more than half were Johanson Type II. Only one case involved the acetabulum. Nearly 17% required revision of some prosthetic component, and about one-third could be resolved orthopaedically. Of cases treated surgically, most complications were related to the surgical wound.

Discussion and Conclusions: The type of treatment used depends on various factors, such as type of fracture and fracture line, patient age, prosthetic loosening, etc. Individualised treatment is therefore the standard. We have observed no abnormalities in bone healing. Although this type of fracture is fortunately rare, we consider good preoperative planning and a thorough postoperative follow-up to be very important for the correct resolution of this difficult problem.