Highly cross-linked polyethylene (HXLPE) greatly reduces wear in total hip arthroplasty, compared to conventional polyethylene (CPE). Cross-linking is commonly achieved by irradiation. This study aimed to compare the degree of cross-linking and in vitro wear rates across a cohort of retrieved and unused polyethylene cups/liners from various brands. Polyethylene acetabular cups/liners were collected at one centre from 1 April 2021 to 30 April 2022. The trans-vinylene index (TVI) and oxidation index (OI) were determined by Fourier-transform infrared spectrometry. Wear was measured using a pin-on-disk test.Aims
Methods
Hyaline cartilage has a low capacity for regeneration. Untreated osteochondral lesions of the femoral head can lead to progressive and symptomatic osteoarthritis of the hip. The purpose of this study is to analyze the clinical and radiological long-term outcome of patients treated with osteochondral autograft transfer. To our knowledge, this study represents a series of osteochondral autograft transfer of the hip with the longest follow-up. We retrospectively evaluated 11 hips in 11 patients who underwent osteochondral autograft transfer in our institution between 1996 and 2012. The mean age at the time of surgery was 28.6 years (8 to 45). Outcome measurement included standardized scores and conventional radiographs. Kaplan-Meier survival curve was used to determine the failure of the procedures, with conversion to total hip arthroplasty (THA) defined as the endpoint.Aims
Methods
There is a considerable challenge in treating bone infections and orthopaedic device-associated infection (ODAI), partly due to impaired penetration of systemically administrated antibiotics at the site of infection. This may be circumvented by local drug administration. Knowledge of the release kinetics from any carrier material is essential for proper application. Ceftriaxone shows a particular constant release from calcium sulphate (CaSO4) in vitro, and is particularly effective against streptococci and a large portion of Gram-negative bacteria. We present the clinical release kinetics of ceftriaxone-loaded CaSO4 applied locally to treat ODAI. A total of 30 operations with ceftriaxone-loaded CaSO4 had been performed in 28 patients. Ceftriaxone was applied as a single local antibiotic in 21 operations and combined with vancomycin in eight operations, and in an additional operation with vancomycin and amphotericin B. Sampling of wound fluid was performed from drains or aspirations. Ceftriaxone concentrations were measured by liquid chromatography with tandem mass spectrometry (LC-MS/MS).Aims
Methods
Implant-associated infection usually require prolonged treatment or even removal of the implant. Local application of antibiotics is used commonly in orthopaedic and trauma surgery, as it allows reaching higher concentration in the affected compartment, while at the same time reducing systematic side effects. Ceftriaxone release from calcium sulphate has a particularly interesting, near-constant release profile in vitro, making it an interesting drug for clinical application. Purpose of the present study was to investigate the potential cytotoxicity of different ceftriaxone concentrations and their influence on osteogenic differentiation of human pre-osteoblasts. Human pre-osteoblasts were cultured up to 28 days in different ceftriaxone concentrations, ranging between 0 mg/L and 50’000 mg/L. Cytotoxicity was determined quantitatively by measuring lactate dehydrogenase release, metabolic activity, and cell proliferation. Gene expression analysis of bone-specific markers as well as mineralization and protein expression of collagen-I (Col-I) were investigated to assess osteogenic differentiation.Aim
Method
In orthopaedic and trauma surgery, implant-associated infections are increasingly treated with local application of antibiotics, which allows a high local drug concentration to be reached without eliciting systematic adverse effects. While ceftriaxone is a widely used antibiotic agent that has been shown to be effective against musculoskeletal infections, high local concentrations may harm the surrounding tissue. This study investigates the acute and subacute cytotoxicity of increasing ceftriaxone concentrations as well as their influence on the osteogenic differentiation of human bone progenitor cells. Human preosteoblasts were cultured in presence of different concentrations of ceftriaxone for up to 28 days and potential cytotoxic effects, cell death, metabolic activity, cell proliferation, and osteogenic differentiation were studied.Aims
Methods
Our retrospective analysis reports the outcome of patients operated for slipped capital femoral epiphysis using the modified Dunn procedure. Results, complications, and the need for revision surgery are compared with the recent literature. We retrospectively evaluated 17 patients (18 hips) who underwent the modified Dunn procedure for the treatment of slipped capital femoral epiphysis. Outcome measurement included standardized scores. Clinical assessment included ambulation, leg length discrepancy, and hip mobility. Radiographically, the quality of epiphyseal reduction was evaluated using the Southwick and Alpha-angles. Avascular necrosis, heterotopic ossifications, and osteoarthritis were documented at follow-up.Aims
Methods
Calcium sulphate (CaSO4) is a resorbable material
that can be used simultaneously as filler of a dead space and as
a carrier for the local application of antibiotics. Our aim was
to describe the systemic exposure and the wound fluid concentrations
of vancomycin in patients treated with vancomycin-loaded CaSO4 as
an adjunct to the routine therapy of bone and joint infections. A total of 680 post-operative blood and 233 wound fluid samples
were available for analysis from 94 implantations performed in 87
patients for various infective indications. Up to 6 g of vancomycin
were used. Non-compartmental pharmacokinetic analysis was performed
on the data from 37 patients treated for an infection of the hip.Aims
Patients and Methods
Thermal stability is a key property in determining the suitability of an antibiotic agent for local application in the treatment of orthopaedic infections. Despite the fact that long-term therapy is a stated goal of novel local delivery carriers, data describing thermal stability over a long period are scarce, and studies that avoid interference from specific carrier materials are absent from the orthopaedic literature. In this study, a total of 38 frequently used antibiotic agents were maintained at 37°C in saline solution, and degradation and antibacterial activity assessed over six weeks. The impact of an initial supplementary heat exposure mimicking exothermically curing bone cement was also tested as this material is commonly used as a local delivery vehicle. Antibiotic degradation was assessed by liquid chromatography coupled to mass spectrometry, or by immunoassays, as appropriate. Antibacterial activity over time was determined by the Kirby-Bauer disk diffusion assay.Objectives
Methods
Thermal stability is a key property determining the suitability of an antibiotic agent for local application. Long-term data describing thermal stability without interference from carrier materials are scarce. In this study, a total of 38 common antibiotic agents have been maintained at 37 °C in saline solution, and degradation and antibacterial activity assessed over 6 weeks. The impact of an initial supplementary heat exposure mimicking exothermically-curing bone cement has also been tested. Antibiotic degradation was assessed by chromatography coupled to mass spectrometry or immunoassays, as appropriate. Antibacterial activity was determined by Kirby-Bauer disk diffusion assay.Aim
Method
Calcium sulphate is a resorbable void filler that can be used for local antibiotic delivery. Results from clinical studies on chronic osteomyelitis thus treated with local vancomycin have already been published. Despite significant exposure to this drug, there are no pharmacokinetic studies published so far. Based on observations in our patients, a model predicting vancomycin serum and wound fluid levels and toxicity potential is presented. Following implantation of Osteoset® added with vancomycin, serum and wound fluid concentrations of this antibiotic have been monitored systematically. The pharmacokinetic analysis was performed using a non-linear mixed-effects model based on a one-compartment model with first-degree absorption.Introduction
Methods
We investigated the role of a functional brace worn for four months in the treatment of patients with an acute isolated tear of the posterior cruciate ligament to determine whether reduction of the posterior tibial translation during the healing period would give an improved final position of the tibia. The initial and follow-up stability was tested by Rolimeter arthrometry and radiography. The clinical outcome was evaluated using the Lysholm score, the Tegner score and the International Knee Documentation Committee scoring system at follow-up at one and two years. In all, 21 patients were studied, 21 of whom had completed one-year and 17 a two-year follow-up. The initial mean posterior sag (Rolimeter measurement) of 7.1 mm (5 to 10) was significantly reduced after 12 months to a mean of 2.3 mm (0 to 6, p <
0.001) and to a mean of 3.2 mm (2 to 7, p = 0.001) after 24 months. Radiological measurement gave similar results. The mean pre-injury Lysholm score was normal at 98 (95 to 100). At follow-up, a slight decrease in the mean values was observed to 94.0 (79 to 100, p = 0.001) at one year and 94.0 (88 to 100, p = 0.027, at two years). We concluded that the posterior cruciate ligament has an intrinsic healing capacity and, if the posteriorly translated tibia is reduced to a physiological position, it can heal with less attentuation. The applied treatment produces a good to excellent functional result.
We assessed differences in the incidence and appearance of the radiological signs of loosening of the cup for various types of design. This was an observational study based on hip registry data of 15 340 patients with 17 951 total hip arthroplasties collected over a period of 33 years in 49 hospitals in Central Europe. The threaded and the press-fit titanium cups showed significantly less aseptic loosening than the other systems. The direction of migration and the frequency of the radiological signs of loosening differed between the cup systems and were time-dependent. Our findings indicate the superiority of uncemented threaded cups and press-fit titanium cups over other designs of cup.
Osteotomies around the knee are still utilized a lot in Europe and in Asia while in US unicompartmental and total arthroplasty for the same indications have more and more taken over, partially due to fear of complications. We think that with careful planning and technique the indications can be maintained. Furthermore with modern methods of cartilage repair it is of utmost importance to unload overloaded compartments. Also many young patients having suffered ligamentous tears of the knee and having been reconstructed are in need of OT’s later on. Many of the poor results are due to absent or poor planning and to poor OT technique and fixation. Not every knee needs to be operated to an overcorrected position. While opening wedge OT has become trendy because of fewer neurological complications we think there are definite indications for closing wedge technique. In this lecture we would like to summarize the principles and the steps which are very personal and that are based on 20 years of practice. Indications for osteotomies around the knee Varus Knee Opening wedge osteotomy: Advantages: Rapid surgery, small incision, fast healing, precise correction. Indicated when:
Degree of OA moderate and angular correction of not >
8° Useful in associated MCL Instability Useful when open surgery on medial femoral condyle needed (Mosaicplasty) In case of associated ACL instability when tibial slope is not >
10° Patella alta
Has a tendency to increase the tibial slope. We use tricortical grafts from the iliac crest where the base of the wedges in mm corresponds to the degrees of correction. A cervical spine AO plate with for screws is used for fixation. Creates less deformity of the proximal tibia which is an advantage for a later total knee. Increases the intraarticular pressure even when the MCL is cut or detached distally, without us knowing the effect on the degree of OA, no long term studies being known to us. Closing wedge osteotomy: Advantages: Allows higher degrees of correction
Degree of OA advanced, need for higher corrections Useful when open surgery on lateral femoral condyle needed In ACL instability when tibial slope must be corrected, because of need to break the medial cortical hinge a heavier implant is needed may be enforced by a sagital Ex.Fix. Patella baja Corrections over 5 degrees need an OT of the proximal or distal fibula. We perform the resecting OT in the fibular neck, the proximal cut is incomplete removing only the anterior and lateral cortex, the distal cut is complete. This allows to shift the distal fragment proximally and in front of the proximal cortical shelf allowing nerve protection. For fixation of the tibial OT we use the 90° angled cannulated AO osteotomy plate, that is inserted over a 2,0 K wire using a specific “transporteur” in relation to the amount of correction. The OT is done using the precise AO osteotomy jig, cutting along 2,5 mm K wires inserted through the jig. The two cuts meet 5–10 mm short of the opposite cortex. The closing wedge OT creates more deformity, carries a certain risk of peroneal nerve injury and of compartment syndrome. Surgery must therefore been done very skilfully and demands expertise. All the studies about long term effect of HTO have been done one using closing wedge technique. Double Osteotomy Indications:
For deformities of over 12° to avoid obliquity of the joint line otherwise created by tibial or femoral OT alone. When sagital deformity needs to be corrected together with frontal plane deformity, eg a flexum of 20° and a varus of 10°. Valgus knee Closing wedge Osteotomy of the distal femur: Advantages are the potent fixation using the same plate as on the tibia leading to rapid healing. Approach is rather extensive. Indicated:
When deformity of valgus and sagital plane ( flexion contracture) need to be addressed. When valgus is marked ( in small deformities the OT can also be performed in the tibia). Opening wedge Osteotomy of the distal femur. Indicated:
When the deformity is small. When cartilage gestures need to be performed on the lateral femoral condyle. Planning of Osteotomies: We use one leg standing films in ap, pa 45° flexion, and lateral projection, varusvalgus stress films with 15 kp (Telos) and Orthoradiogramm (hip-ankle). A potential contralateral opening on the standing film is compensated on the drawing by a push orthoradiogram which virtually brings both compartments into contact. For the varus knee the ideal crossing point of the mechanical xis sits at 30% in the lateral compartment, the centre between the tibial eminences being 0% the medial or lateral border of the tibia being 100%. This is the displacement corresponds to the classical 3° over-correction that is useful when the medial compartment is down to bone. This would be an overcorrection for the less damaged medial joint lines where however an OT may already be indicated. We therefore have prospectively studied and validated a more balanced approach. If the medial compartment in a varus knee has lost up to one third of his cartilage the axis is calculated to pass at 10% in the lateral compartment. If is down by two thirds it is meant to pass at 20% laterally. If it is totally worn it passes at 30%. The drawing for the high tibial OT on the orthoradiogram is simple:
Connect the centre of the femoral head with the point at 10, rsp. 20, rsp. 30% in the lateral compartment and prolong this new axis of the leg distally to a point lateral of the ankle joint. Now select the hinge joint for the opening or closing wedge OT 2–3 cm distal to the joint line and connect this point with the old and the new centre of the ankle. Measure the angle between the t line which corresponds to the amount of correction and the angle to open or resect. The planning for the varus OT of the distal femur in valgus deformity is somewhat more complicated but should aim at a correction which leaves a femorotibial valgus of 1–2°. Using these rules one is able to reach adequate correction.
Minimally invasive plate osteosynthesis is a technically feasible surgical alternative to treat displaced diaphyseal fractures of the tibia. In recent years, this technique has evolved in response to the poor results following tibial fracture stabilization using the traditional open method of plate fixation. Devascularisation with periosteal stripping of bone fragments using open reduction and internal fixation to ensure adequate fracture visualisation led to a substantial percentage of complications including deep infection, delayed union or non union, and refractures after plate removal. Using the technique of minimally invasive plate osteosynthesis, fracture management is achieved with closed reduction followed by stabilisation using a subcutaneous epiperiosteal LC-DC-plate. Twenty-four patients with 25 tibial fractures were treated by minimally invasive plate osteosynthesis at the Kantonsspital, Fribourg, Switzerland, between 1997 and 1999. These cases were retrospectively reviewed. There were 11 male and 13 female patients with a mean age of 41 years (range 16 -64). Nineteen tibial diaphyseal fractures (7 type A, 11 type B, and 1 type C) and six tibial epiphyseal-metaphyseal fractures (4 type A, 1 type B, and 1 type C) were surgically treated. Three fractures were open (grade I). Twenty-four fractures were treated using a 4.5 mm titanium LC-DC-plate, and in one fracture a 4.5 mm stainless steel DC-plate was used for tibial fixation. Open reduction and internal fixation of the fibula was necessary in eleven fractures, nine of which were stabilized with a one-third tubular plate and two with a 3.5 mm LC-DC-plate. The postoperative regimen included partial weight bearing for eight weeks followed by progressive and protected weight bearing until fracture union was achieved. Fracture union was confirmed with radiographs obtained at six to eight weeks, twelve to sixteen weeks, and at final follow-up. The mean time to final follow-up was eighteen months. All fractures had solidly united within four months postoperatively. Radiographically, healing was characterised by callus formation located on the lateral and posterior aspects of the tibial diaphysis, and was similar to that which is usually seen after stabilisation of tibial fractures using an intramedullary rod. Both ankle and knee range of motion were similar to the uninjured side by final follow-up. There were eight cases of residual valgus malalignment of less than five degrees, and were associated with distal third tibial diaphyseal fractures with concomitant fibula fractures which were not rigidly stabilised. Postoperative complications included two deep wound infections and one postoperative compartment syndrome. Overall good results were obtained by using minimally invasive plate osteosynthesis of diaphyseal fractures of the tibia. Although this technique is more technically demanding than standard open reduction and internal fixation of tibial diaphyseal fractures, preservation of the soft tissue envelope and periosteal blood supply is beneficial for fracture healing. Surgical indications for minimally invasive plate osteosynthesis of the tibial diaphysis include a narrow tibial medullary canal as well as distal and proximal metaphyseal fractures not suitable for intramedullary rodding, and associated intra-articular tibial fractures. Minimally invasive plate osteosynthesis should be considered as a surgical alternative for the treatment of displaced diaphyseal fractures of the tibia.
We reviewed retrospectively 11 patients who had been treated surgically by open autologous osteochondral grafting for symptomatic chondral or osteochondral defects of the dome of the talus between 1996 and 1999. The mean ages of the eight men and three women were 34.2 and 25.9 years, respectively, with a mean time to follow-up of 24 months. The results of functional outcome were prospectively obtained using the MODEMS AAOS foot and ankle follow-up questionnaire, the AOFAS ankle-hindfoot scale and the Hannover scores for the ankle. The grafts were harvested from the ipsilateral knee. Good to excellent results were obtained for the ankle without adverse effects on the knee. We believe that autologous osteochondral grafting should be considered for the patient with a symptomatic osteochondral defect of the talus.
Surgical dislocation of the hip is rarely undertaken. The potential danger to the vascularity of the femoral head has been emphasised, but there is little information as to how this danger can be avoided. We describe a technique for operative dislocation of the hip, based on detailed anatomical studies of the blood supply. It combines aspects of approaches which have been reported previously and consists of an anterior dislocation through a posterior approach with a ‘trochanteric flip’ osteotomy. The external rotator muscles are not divided and the medial femoral circumflex artery is protected by the intact obturator externus. We report our experience using this approach in 213 hips over a period of seven years and include 19 patients who underwent simultaneous intertrochanteric osteotomy. The perfusion of the femoral head was verified intraoperatively and, to date, none has subsequently developed avascular necrosis. There is little morbidity associated with the technique and it allows the treatment of a variety of conditions, which may not respond well to other methods including arthroscopy. Surgical dislocation gives new insight into the pathogenesis of some hip disorders and the possibility of preserving the hip with techniques such as transplantation of cartilage.
The primary source for the blood supply of the head of the femur is the deep branch of the medial femoral circumflex artery (MFCA). In posterior approaches to the hip and pelvis the short external rotators are often divided. This can damage the deep branch and interfere with perfusion of the head. We describe the anatomy of the MFCA and its branches based on dissections of 24 cadaver hips after injection of neoprene-latex into the femoral or internal iliac arteries. The course of the deep branch of the MFCA was constant in its extracapsular segment. In all cases there was a trochanteric branch at the proximal border of quadratus femoris spreading on to the lateral aspect of the greater trochanter. This branch marks the level of the tendon of obturator externus, which is crossed posteriorly by the deep branch of the MFCA. As the deep branch travels superiorly, it crosses anterior to the conjoint tendon of gemellus inferior, obturator internus and gemellus superior. It then perforates the joint capsule at the level of gemellus superior. In its intracapsular segment it runs along the posterosuperior aspect of the neck of the femur dividing into two to four subsynovial retinacular vessels. We demonstrated that obturator externus protected the deep branch of the MFCA from being disrupted or stretched during dislocation of the hip in any direction after serial release of all other soft-tissue attachments of the proximal femur, including a complete circumferential capsulotomy. Precise knowledge of the extracapsular anatomy of the MFCA and its surrounding structures will help to avoid iatrogenic avascular necrosis of the head of the femur in reconstructive surgery of the hip and fixation of acetabular fractures through the posterior approach.
In order to investigate the functional anatomy of gluteus minimus we dissected 16 hips in fresh cadavers. The muscle originates from the external aspect of the ilium, between the anterior and inferior gluteal lines, and also at the sciatic notch from the inside of the pelvis where it protects the superior gluteal nerve and artery. It inserts anterosuperiorly into the capsule of the hip and continues to its main insertion on the greater trochanter. Based on these anatomical findings, a model was developed using plastic bones. A study of its mechanics showed that gluteus minimus acts as a flexor, an abductor and an internal or external rotator, depending on the position of the femur and which part of the muscle is active. It follows that one of its functions is to stabilise the head of the femur in the acetabulum by tightening the capsule and applying pressure on the head. Careful preservation or reattachment of the tendon of gluteus minimus during surgery on the hip is strongly recommended.
