Palmitic acid coating of allogeneic cancellous bone for local antibiotic treatment: A porcine impaction bone grafting model

Introduction

The worldwide rising number of joint replacements results in increasing revision surgery including a relevant portion of septic loosening accompanied by bone deficiencies. Loading of allogeneic bone with antibiotics provides high local antibiotic concentrations and might eradicate bacteria which appear resistant to systemic antibiotic application. Hydrophobic palmitic acid was shown to be a suitable carrier for antibiotics and prevents biofilm.

Methods

Cancellous bone derived from 6 to 7 months old piglets was used for a standardized in vitro impaction bone grafting model according to previous studies. The specimens were either thermodisinfected or remained native and palmitic acid with one third and two third partial weight were added and compared with control. Shear force at the interface prosthesis to cement and between cement and bone was measured. The relative micromovements were measured with 6 inductive sensors with a resolution of 0.1 μm at three different measuring heights up to a maximum movement of 150 μm between cement and bone. Taking into account the corresponding applied torque the measured values were normalized in μm/Nm. Statistical analysis was done with SPSS Statistics® Version 26.0 IBM.

Results

Smallest movement was measured for thermodisinfected cancellous bone and a not significant decrease of shear force resistance with addition of palmitic acid was found since supplementing native cancellous bone reduced shear force resistance significantly depending on the weight percentage of palmitic acid.

Conclusion

Supplementation of porcine cancellous bone with palmitic acid did not significantly reduce shear force resistance of thermodisinfected bone since adding palmitic acid to native bone decreased it significantly depending on the volume added. Palmitic acid seems to be a suitable coating for allogeneic cancellous bone to deliver high local antibiotic concentrations and thermodisinfected cancellous bone might be able to store larger volumes of palmitic acid than native bone without relevant influence on shear force resistance.

Effect of synthetic bone replacement material of different size on shear stress resistance within impacted native and thermodisinfected cancellous bone: an in vitro femoral impaction bone grafting model

Antibiotic carrier particles of variable size might influence mechanic properties within impacted thermodisinfected and native cancellous bone different. Herafill®G containing calciumsulfate and calciumcarbonate provides high local concentrations of gentamicin being important for revision surgery in infected joint replacements. Native and thermodisinfected cancellous bone derived from 6 to 7 months old piglets was used for in vitro impaction bone grafting and supplemented each with Herafill®G granules of two different sizes. Micromovement of implants related to shear force was measured in 29 specimens distributed in 6 groups. Thermodisinfected cancellous bone revealed a significant higher shear force resistance than native bone with a mean difference of 423.8 mdeg/Nm (p < 0.001) ranging within 95% confidence interval from 181.5 to 666.0 mdeg/Nm. Adding small granules to thermodisinfected bone did not reduce shear force resistance significantly since adding large granules to native bone improved it by 344.0 mdeg/Nm (p < 0.003). Shear force resistance was found higher at the distal region of the implant compared to a proximal point of measurement throughout all specimens. Less impaction impulses were necessary for thermodisinfected bone. Thermodisinfected cancellous bone might achieve a higher degree of impaction compared with native bone resulting in increased resistance against shear force since impaction was found increased distally. Supplementation of thermodisinfected bone with small granules of Herafill®G might be considered for application of local antibiotics. Large granules appeared more beneficial for supplementation of native bone. Heterogeneity of bone graft and technical aspects of the impaction procedure have to be considered regarding the reproducibility of femoral impaction bone grafting.

Influence of antibiotic pellets on pore size and shear stress resistance of impacted native and thermodisinfected cancellous bone: An in vitro femoral impaction bone grafting model

Introduction

Morphology and mechanic properties of impacted cancellous bone are affected by carrier substances which provide high local concentrations of antibiotics.

Methods

Bone chips were taken from the femoral head of 6-7 months old piglets. One half was thermodisinfected and the other remained native. Ten specimens each were mixed with Herafill® antibiotic pellets and a control group of each 10 specimens respectively was examined. The cancellous bone was impacted according to Exeter technique and the implants were cemented. The distribution of the particles and the pores were defined with three dimensional computertomographic scan and shear force resistance was measured until failure.

Results

Shear force resistance was not measured significantly less for thermodisinfected (2.7 Nm) compared with native bone (3.5 Nm) and addition of antibiotic pellets reduced shear force resistance in both groups since this was significant for the native group. The average pore volume of the native bone specimens appeared significant smaller compared to the thermodisinfected group (p = 0.011) and the pore volume showed a negative correlation with shear force resistance (p = 0.044). Pore volume around the pellets was found significantly increased and it appeared smaller for native bone. The number of pellets located next to the implant showed a negative correlation with shear force resistance (p = 0.034) and the negative correlation increased for pellets below the tip of the shaft model (p = 0.024).

Conclusion

Adding antibiotic pellets to native and thermodisinfected impacted cancellous bone increased pore volume since the area around the pellets showed increased porosity which correlated with reduced shear force resistance. Computertomographic three dimensional measurement of porosity might predict shear force resistance of impacted cancellous bone and improve impaction of bone grafting intraoperatively.

Development and current use of local antibiotic carriers in spondylodiscitis : Pilot study on reduction of duration of systemic treatment

BACKGROUND

The current study situation regarding the duration of systemic antibiotic treatment for spondylodiscitis is inhomogeneous and varies between 4-12 weeks. Due to the many undesirable side effects the aim is to achieve complete healing without recurrence or hematogenous scatter within the shortest possible period of time. The present pilot study investigated whether the additional application of a local antibiotic carrier to the surgically treated intervertebral disc space can contribute to a further reduction of treatment duration.

MATERIAL AND METHODS

In the pilot study 20 patients with acute spondylodiscitis and indications for surgical intervention were included. Surgical treatment was carried out by dorsal instrumentation, radical debridement of the site of infection, and cage interposition in the affected disc space. The remaining disc space was filled with homologous cancellous bone and antibiotic-loaded calcium sulfate hydroxyapatite pellets. A classification into a long-term and a short-term antibiotic group was performed. Both groups initially received a 10-day parenteral antibiotic administration. This was followed by oral antibiotics for 2 or 12 weeks, depending on the group. During the 12-month follow-up inflammation parameters, the local infection situation as well as the bony fusion and antibiotic tolerance were regularly checked.

RESULTS

The average age of the patients was 66.7 ± 11.2 years. Intraoperative detection of pathogens was successful in 65%. In 60% the antibiotic carrier was loaded with gentamicin, in 40% with vancomycin. At follow-up, all patients except one in the short-term antibiotic group had inflammation parameters within the normal range after 3 months. In the long-term antibiosis group, two patients still showed elevated infection values after 3 months, otherwise the values were within the normal range. After 12 months a complete cure of the infection was achieved in all patients. Antibiotic treatment intolerance occurred in 10% of the short-term antibiotic group and in 50% of the long-term group.

CONCLUSION

The results of the present pilot study show that with the additional use of absorbable local antibiotic carriers in the surgical treatment of bacterial spondylodiscitis it is possible to shorten the duration of systemic antibiotic treatment to 3 weeks. This can reduce the side effects and incompatibility of treatment and still achieve similar healing results.

Different injury patterns after snowboard in children and adolescents

Background

Snowboarding is a very common sport especially among young adults. Common injuries are hand, wrist, shoulder and ankle injuries.

Purpose

of this study was to analyze different injury pattern in children and young adults comparing with adults.

Methods

Patients who were admitted for ambulant or stationary treatment as a result of injury practicing snowboard received a questionnaire and were divided into three groups (children, young adults and adults) according to their age. Between october 2002 and may 2007 1929 injured snowboard sportsmen were included in the study. Data such as location, date and time of accident as well as information about the slope were carried out. In addition snowboard skills were classified and patients were questioned whether they wore special protectors.

Results

32.5% of injured patients were female (n = 626) and 67.5% male (n = 1303) with a mean age of patients of 21.9 (7-66) years. 13% of all patients were in group I (children), 19.2% in group II (young adults) and 67.8% in group III (adults).Most common injuries with 60% of all accidents were injuries of the hand wrist especially in children beginning with snowboard sports. Injuries on the regular track were most common followed by jumps in the kicker park and rails in the fun-park. 20.6% in group I, 13.6% in group II and 12.8% group III did not wear any protectors.

Conclusion

Children and adolescents presented different injury patterns than adults. Young participants of up to 14 years of age are endangered especially during the first days of learning this sport. Further development of protectors with regard to biomechanical characteristics is important to achieve an optimal protective effect.

Level of evidence

2b.

[Allogeneic bone transplantation in hip revision surgery : Indications and potential for reconstruction]

The increasing number of people having joint replacements will lead to increasing numbers of revision operations. The transplantation of allogeneic bones might reconstruct bone defects and improve long-term anchorage of the implant. A sufficient primary stability of the implanted construct is necessary to achieve osseous incorporation as well as tight contact between the implanted allogeneic and host bones. Transplantation of bone can contribute to downgrading acetabular defects and so avoid bigger reinforcement implants. An improvement of bone stock due to reconstruction of femoral bony defects might also reduce the size of the stem necessary since the indication might be limited in case of extensive bone defects. According to good longterm results of modular revision stems the Impaction-Bone-Grafting has not yet generally been established.

Instrumented gait analysis in patients with medial osteoarthritis of the knee after mobile-bearing unicompartmental knee arthroplasty

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is an effective treatment for patients with medial osteoarthritis of the knee joint. Instrumented gait analysis provides an objective measure to quantify and qualify postoperative changes of gait. The purpose of this study was to evaluate standardized instrumented gait analysis for functional recovery and gait as an outcome of mobile-bearing UKA in patients with medial osteoarthritis of the knee.

METHODS

Twenty-one patients with isolated medial osteoarthritis of the knee joint received mobile-bearing UKA. They were examined by a gait analysis before surgery and after an average follow-up time of seven months. Gait analysis was performed on a treadmill with six infrared-cameras to identify changes of gait characteristics (e.g., velocity, stride time, stride length, knee adduction and hip abduction).

RESULTS

Mean velocity (chosen by individuals) increased from 0.61 to 0.76m/s and further significant advancements, particularly in the knee adduction and the hip abduction were detected. Time and length of strides improved significantly as well as the clinical scores American Knee Society Score (AKSS), Oxford-12, Hannover Functional Ability Questionnaire for Osteoarthritis (FFbH-OA) Score and Devane Score.

CONCLUSION

Mobile-bearing UKA can restore physiological axis of the leg and improve gait and function of the knee joint. The combination of instrumented gait analysis with clinical scores constitutes an eligible measuring instrument to quantify and qualify changes in patients' gait patterns.

Micro-CT and micro-FE analysis of pedicle screw fixation under different loading conditions

Anchorage of pedicle screw instrumentation in the elderly spine with poor bone quality remains challenging. In this study, micro finite element (µFE) models were used to assess the specific influence of screw design and the relative contribution of local bone density to fixation mechanics. These were created from micro computer tomography (µCT) scans of vertebras implanted with two types of pedicle screws, including a full region-or-interest of 10 mm radius around each screw, as well as submodels for the pedicle and inner trabecular bone of the vertebral body. The local bone volume fraction (BV/TV) calculated from the µCT scans around different regions of the screw (pedicle, inner trabecular region of the vertebral body) were then related to the predicted stiffness in simulated pull-out tests as well as to the experimental pull-out and torsional fixation properties mechanically measured on the corresponding specimens. Results show that predicted stiffness correlated excellently with experimental pull-out strength (R² > 0.92, p < .043), better than regional BV/TV alone (R2 = 0.79, p = .003). They also show that correlations between fixation properties and BV/TV were increased when accounting only for the pedicle zone (R² = 0.66-0.94, p ≤  .032), but with weaker correlations for torsional loads (R² < 0.10). Our analyses highlight the role of local density in the pedicle zone on the fixation stiffness and strength of pedicle screws when pull-out loads are involved, but that local apparent bone density alone may not be sufficient to explain resistance in torsion.

Behandlungsalgorithmus von Wundinfektionen an der Wirbelsäule mit ersten Ergebnissen einer retrospektiven Studie zur Behandlung von postoperativen Wundinfektionen mit Vakuumsystemen

Die postoperative Wundinfektion ist eine der häufigsten Komplikationen in der Wirbelsäulenchirurgie. Sie verlängert den Leidensweg des Patienten und stellt oftmals eine große Herausforderung an das gesamte Behandlungsteam dar. Zahlreiche Risikofaktoren sind in der Literatur bereits beschrieben, die es präoperativ zu optimieren gilt, um Infektionen zu vermeiden. Bezüglich der Therapie von Wundinfektionen gibt es bei mangelnder Studienlage keine einheitlichen Richtlinien. Oftmals sind mehrere Revisionen erforderlich, bis eine Wundinfektion zur Ausheilung kommt. Im vorliegenden Artikel wird ein interner Algorithmus zur Behandlung postoperativer Wundinfektionen vorgestellt. Unter Zuhilfenahme der VAC-Therapie bei tiefen Wundinfektionen zeigt sich eine erfolgreiche Infektsanierung vor allem auch im Hinblick auf den Implantaterhalt. Zukünftige Studien können helfen die Therapie der Wundinfektionen weiter zu optimieren, die Anzahl der Revisionen zu senken und allgemeingültige Standards zu entwickeln.

Transforaminal lumbar interbody fusion using polyetheretherketone oblique cages with and without a titanium coating: a randomised clinical pilot study

AIMS

We compared the clinical and radiological outcomes of using a polyetheretherketone cage with (TiPEEK) and without a titanium coating (PEEK) for instrumented transforaminal lumbar interbody fusion (TLIF).

MATERIALS AND METHODS

We conducted a randomised clinical pilot trial of 40 patients who were scheduled to undergo a TLIF procedure at one or two levels between L2 and L5. The Oswestry disability index (ODI), EuroQoL-5D, and back and leg pain were determined pre-operatively, and at three, six, and 12 months post-operatively. Fusion rates were assessed by thin slice CT at three months and by functional radiography at 12 months.

RESULTS

At final follow-up, one patient in each group had been lost to follow-up. Two patients in each of the PEEK and TiPEEK groups were revised for pseudarthrosis (p = 1.00). The rate of complete or partial fusion at three months was 91.7% in both groups. Overall, there were no significant differences in ODI or in radiological outcomes between the groups.

CONCLUSION

Favourable results with identical clinical outcomes and a high rate of fusion was seen in both groups. The titanium coating appears to have no negative effects on outcome or safety in the short term. A future study to determine the effect of titanium coating is warranted. Cite this article: Bone Joint J 2017;99-B:1366-72.

[Skeletal hemangiomas]

Hemangiomas are benign tumors, which are mainly composed of neoplastic blood vessels. The exact pathogenesis is still unclear. They are the most common benign spinal tumors and also occur less commonly in the bones of the extremities. Hemangiomas are often clinically asymptomatic and are diagnosed as incidental findings. Women are affected more frequently than men (2:1). The X‑ray and computed tomography (CT) diagnostics typically demonstrate the classical honeycombing or vertically orientated lucencies separated by thickened cancellous bone in the affected skeletal section. Vertebral hemangiomas are hyperintense in both T1 and T2-weighted magnetic resonance imaging (MRI). The treatment of vertebral hemangiomas ranges from irradiation, embolization and vertebroplasty to operative decompression, resection of the tumor and instrumented stabilization. In the long bones intralesional curettage and bone grafting with additive osteosynthesis is the main treatment modality. The prognosis for osseous hemangiomas is good.

[History of internal fixators. The subsequent importance for spinal surgery]

BACKGROUND

This article presents a retrospective look at spinal implants of the 1970s and 1980s.

OBJECTIVE

The historical development of internal fixators as the successor to external fixators.

MECHANICAL PRINCIPLE

Pedicled screws are stably anchored in vertebral bodies of the thoracic or lumbar spine or the sacrum using a dorsal approach. They are joined by a rod as a longitudinal support, separated by freely selectable distances and in any desirable and initially modifiable angle. After locking this results in an angular and rotationally stable completely sunken bilateral construction for fixing two or more vertebrae together and the position can be manually adjusted using long lever arms on the pedicled screws.

RESULTS

The first in vivo application in humans was on 22 December 1982 in Basel. The initial indications were unstable spinal fractures. The expectations placed on the new working principle of internal fixation and its realization were confirmed and short stretch fixation exclusively of the neighboring vertebra and immediate mobilization of patients could be routinely achieved. The indications were extended to include instability of the spine for conditions outside the field of traumatology. Further developments of implants and other technical solutions in the coupling system using the same basic principle in the direction of multisegmental applications, ease of operation and titanium-based materials became internationally established and were developed into universal spinal stabilization systems for spinal degeneration, deformities, tumors and olisthesis.

CONCLUSION

The basic principle of spinal fixators (internal and external) is contained in the complete product range of dorsal stabilizing implants from practically all manufacturers worldwide and has become taken for granted.

Comparative lipidomic analysis of synovial fluid in human and canine osteoarthritis

OBJECTIVE

The lipid profile of synovial fluid (SF) is related to the health status of joints. The early stages of human osteoarthritis (OA) are poorly understood, which larger animals are expected to be able to model closely. This study examined whether the canine groove model of OA represents early OA in humans based on the changes in the lipid species profile in SF. Furthermore, the SF lipidomes of humans and dogs were compared to determine how closely canine lipid species profiles reflect the human lipidome.

METHODS

Lipids were extracted from cell- and cellular debris-free knee SF from nine donors with healthy joints, 17 patients with early and 13 patients with late osteoarthritic changes, and nine dogs with knee OA and healthy contralateral joints. Lipid species were quantified by electrospray ionization tandem mass spectrometry (ESI-MS/MS).

RESULTS

Compared with control canine SF most lipid species were elevated in canine OA SF. Moreover, the lipid species profiles in the canine OA model resembled early OA profiles in humans. The SF lipidomes between dog and human were generally similar, with differences in certain lipid species in the phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and sphingomyelin (SM) classes.

CONCLUSIONS

Our lipidomic analysis demonstrates that SF in the canine OA model closely mimics the early osteoarthritic changes that occur in humans. Further, the canine SF lipidome often reflects normal human lipid metabolism.

[Therapy of scoliosis from a historical perspective]

Scoliosis can be considered as one of the classical orthopedic diseases of the spine. The history of orthopedics is closely connected to the development of the therapy of scoliosis. In the eighteenth and the beginning of the nineteenth centuries the therapy of scoliosis was mainly a conservative corrective orthopedic treatment with a variety of corset forms and extension bed treatment. In the middle of the nineteenth century physiotherapy (movement therapy) became established as an supplementary active treatment. The first operations for treatment of scoliosis were carried out in 1839. The real success with surgical procedures for improvement in corrective options was connected to the introduction of metal spinal implants in the early 1960s.

[Posterior lumbar interbody fusion implants. Software assisted planning--preliminary results]

BACKGROUND

Sagittal imbalance, adjacent segment degeneration, and loss of correction due to cage sintering are the main reasons for revision surgery after lumbar fusion. Based on the experience from hip and knee replacement surgery, preoperative software-assisted planning combined with the corresponding cages is helpful to achieve better long-term results.

OBJECTIVES

Evaluation of the procedure regarding intraoperative application of preoperative planning and examination to what extent the planning was correct.

MATERIALS AND METHODS

In all, 30 patients were included in the period from September 2012 to May 2013 in an observational study, planned preoperatively with the planning software, and treated with the corresponding PLIF cages. The radiological evaluation was performed by thin-layer CT after 3 months.

RESULTS

A total of 24 (80%) patients were followed up after 3 months. In these 24 patients, the preoperative planning actually was correct in 17 cases with the intraoperatively implanted cage, which corresponds to a match of about 71%. The fusion rate for these 24 patients who underwent full examinations was 91.7%.

CONCLUSION

The results of this observational study to evaluate the planning of intervertebral cages show positive experience with this novel therapeutic concept. Despite the limited number of participants, good results were observed for the intraoperative implementation of the planned cages and an adequate fusion rate was obtained. Irrespective of this, a software-based surgical planning must be questioned critically any time. Ultimately, it is the surgeon's responsibility to modify the planned procedure intraoperatively if necessary. Currently, the influence of this planning regarding the long-term course and the important question of adjacent segment instability remains unanswered.

Short-term effects of acupuncture and stretching on myofascial trigger point pain of the neck: a blinded, placebo-controlled RCT

OBJECTIVES

This trial aimed to evaluate the short-term effectiveness of acupuncture plus stretching to reduce pain and improve range of motion in patients afflicted by cervical myofascial pain syndrome.

DESIGN

Randomized, blinded, placebo-controlled crossover study.

INTERVENTION

Nineteen patients (11 females, eight males, 33 ± 14 years) with myofascial neck pain in randomized order received the following treatments with one week washout between: acupuncture, acupuncture plus stretching, and placebo laser acupuncture.

MAIN OUTCOME MEASURES

Mechanical pain threshold (MPT, measured with a pressure algometer) represented the primary outcome. Secondary outcomes were motion-related pain (Visual Analogue Scale, VAS) and cervical range of motion (ROM, recorded by means of an ultrasonic 3D movement analysis system). Outcomes were assessed immediately prior as well as 5, 15 and 30 min post treatment. Friedman tests with post hoc Bonferroni-Holm correction were applied to compare differences between treatments.

RESULTS

Both acupuncture as well as acupuncture plus stretching increased MPT by five, respectively, 11 percent post treatment. However, only acupuncture in combination with stretching was superior to placebo (p<0.05). There were no significant differences between interventions at 15 and 30 min post treatment. VAS did not differ between treatments at any measurement. Five minutes after application of acupuncture plus stretching, ROM was significantly increased in the frontal and the transversal plane compared to placebo (p<0.05).

CONCLUSIONS

The combination of acupuncture and stretching could represent a suitable treatment option to improve cervical movement behavior and reduce trigger point pain in the short-term. However, additional studies further discriminating the placebo effects are still warranted.

74 MHz nonthermal emission from molecular clouds: evidence for a cosmic ray dominated region at the galactic center

We present 74 MHz radio continuum observations of the Galactic center region. These measurements show nonthermal radio emission arising from molecular clouds that is unaffected by free–free absorption along the line of sight. We focus on one cloud, G0.13-0.13, representative of the population of molecular clouds that are spatially correlated with steep spectrum (α(327MHz)(74MHz) = 1.3 ± 0.3) nonthermal emission from the Galactic center region. This cloud lies adjacent to the nonthermal radio filaments of the Arc near l 0.2° and is a strong source of 74 MHz continuum, SiO (2-1), and Fe I Kα 6.4 keV line emission. This three-way correlation provides the most compelling evidence yet that relativistic electrons, here traced by 74 MHz emission, are physically associated with the G0.13-0.13 molecular cloud and that low-energy cosmic ray electrons are responsible for the Fe I Kα line emission. The high cosmic ray ionization rate 10(–1)3 s(–1) H(–1) is responsible for heating the molecular gas to high temperatures and allows the disturbed gas to maintain a high-velocity dispersion. Large velocity gradient (LVG) modeling of multitransition SiO observations of this cloud implies H2 densities 10(4–5) cm(–3) and high temperatures. The lower limit to the temperature of G0.13-0.13 is 100 K, whereas the upper limit is as high as 1000 K. Lastly, we used a time-dependent chemical model in which cosmic rays drive the chemistry of the gas to investigate for molecular line diagnostics of cosmic ray heating. When the cloud reaches chemical equilibrium, the abundance ratios of HCN/HNC and N2H+/HCO+ are consistent with measured values. In addition, significant abundance of SiO is predicted in the cosmic ray dominated region of the Galactic center. We discuss different possibilities to account for the origin of widespread SiO emission detected from Galactic center molecular clouds.

Pressurisation leads to better cement penetration into the glenoid bone: a cadaveric study

The aim of this study was to compare a third-generation cementing procedure for glenoid components with a new technique for cement pressurisation. In 20 pairs of scapulae, 20 keeled and 20 pegged glenoid components were implanted using either a third-generation cementing technique (group 1) or a new pressuriser (group 2). Cement penetration was measured by three-dimensional (3D) analysis of micro-CT scans. The mean 3D depth of penetration of the cement was significantly greater in group 2 (p < 0.001). The mean thickness of the cement mantle for keeled glenoids was 2.50 mm (2.0 to 3.3) in group 1 and 5.18 mm (4.4 to 6.1) in group 2, and for pegged glenoids it was 1.72 mm (0.9 to 2.3) in group 1 and 5.63 mm (3.6 to 6.4) in group 2. A cement mantle < 2 mm was detected less frequently in group 2 (p < 0.001). Using the cement pressuriser the proportion of cement mantles < 2 mm was significantly reduced compared with the third-generation cementing technique.

Humeral surface replacement for the sequelae of fractures of the proximal humerus

Fractures of the proximal humerus can lead to malalignment of the humeral head, necrosis and post-traumatic osteoarthritis. In such cases surface replacement might be a promising option. A total of 28 shoulders with glenohumeral arthritis subsequent to a fracture underwent surface replacement arthroplasty of the humeral head in patients with a mean age of 60 years (35 to 83). On the basis of the inclination of the impacted head, post-traumatic arthritis was divided into three types: type 1, an impacted fracture of the head in an anatomical position (seven cases); type 2, a valgus impacted fracture (13 cases); type 3, a varus impacted fracture (eight cases). The outcome was measured by means of the Constant score. According to the Boileau classification of the sequelae of fractures of the proximal humerus, all 28 patients had a final result of intra-capsular category 1. The mean Constant score for the 28 shoulders increased from 23.2 points (2 to 45) pre-operatively to 55.1 points (20 to 89) at a mean of 31 months (24 to 66) post-operatively. Valgus impacted fractures had significantly better results (p < 0.039). Surface replacement arthroplasty can provide good results for patients with post-traumatic osteoarthritis of the shoulder. Their use avoids post-operative complications of the humeral shaft, such as peri-prosthetic fractures. Further surgery can be undertaken more easily as the bone stock is preserved.

[Significance of bone mineral density and modern cementing technique for in vitro cement penetration in total shoulder arthroplasty]

AIM

Loosening of the glenoid component is one of the major causes of failure in total shoulder arthroplasty. Possible risk factors for loosening of cemented components include an eccentric loading, poor bone quality, inadequate cementing technique and insufficient cement penetration. The application of a modern cementing technique has become an established procedure in total hip arthroplasty. The goal of modern cementing techniques in general is to improve the cement-penetration into the cancellous bone. Modern cementing techniques include the cement vacuum-mixing technique, retrograde filling of the cement under pressurisation and the use of a pulsatile lavage system. The main purpose of this study was to analyse cement penetration into the glenoid bone by using modern cement techniques and to investigate the relationship between the bone mineral density (BMD) and the cement penetration. Furthermore we measured the temperature at the glenoid surface before and after jet-lavage of different patients during total shoulder arthroplasty. It is known that the surrounding temperature of the bone has an effect on the polymerisation of the cement. Data from this experiment provide the temperature setting for the in-vitro study.

METHOD

The glenoid surface temperature was measured in 10 patients with a hand-held non-contact temperature measurement device. The bone mineral density was measured by DEXA. Eight paired cadaver scapulae were allocated (n = 16). Each pair comprised two scapulae from one donor (matched-pair design). Two different glenoid components were used, one with pegs and the other with a keel. The glenoids for the in-vitro study were prepared with the bone compaction technique by the same surgeon in all cases. Pulsatile lavage was used to clean the glenoid of blood and bone fragments. Low viscosity bone cement was applied retrogradely into the glenoid by using a syringe. A constant pressure was applied with a modified force sensor impactor. Micro-computed tomography scans were applied to analyse the cement penetration into the cancellous bone.

RESULTS

The mean temperature during the in-vivo arthroplasty of the glenoid was 29.4 °C (27.2-31 °C) before and 26.2 °C (25-27.5 °C) after jet-lavage. The overall peak BMD was 0.59 (range 0.33-0.99) g/cm (2). Mean cement penetration was 107.9 (range 67.6-142.3) mm (2) in the peg group and 128.3 (range 102.6-170.8) mm (2) in the keel group. The thickness of the cement layer varied from 0 to 2.1 mm in the pegged group and from 0 to 2.4 mm in the keeled group. A strong negative correlation between BMD and mean cement penetration was found for the peg group (r (2) = -0.834; p < 0.01) and for the keel group (r (2) = -0.727; p < 0.041). Micro-CT shows an inhomogenous dispersion of the cement into the cancellous bone.

CONCLUSIONS

Data from the in-vivo temperature measurement indicate that the temperature at the glenohumeral surface under operation differs from the body core temperature and should be considered in further in-vitro studies with human specimens. Bone mineral density is negatively correlated to cement penetration in the glenoid. The application of a modern cementing technique in the glenoid provides sufficient cementing penetration although there is an inhomogenous dispersion of the cement. The findings of this study should be considered in further discussions about cementing technique and cement penetration into the cancellous bone of the glenoid.

[Cementless humeral surface replacement arthroplasty in patients less than 55 years of age]

BACKGROUND

Cementless humeral surface replacement arthroplasty is a viable treatment option for degenerative diseases of the shoulder joint. The aim of this prospective study was to analyse the results of this treatment option in patients younger than 55 years of age with different pathologies of the shoulder.

PATIENTS AND METHODS

Twenty-three patients (26 implants) treated with cementless humeral surface replacement arthroplasty were included in this study. Mean follow-up was 2.5 years (1-6 years). Ten patients had posttraumatic osteoarthritis, seven had primary osteoarthritis, and six had osteonecrosis. Patients were evaluated using the Constant score, shoulder motion, and subjective satisfaction.

RESULTS

The mean Constant score increased significantly from 33 points preoperatively (8-69 points) to 61 points postoperatively (25-83 points; p<0.0001), adjusted to age and gender from 38% (8-86%) to 70% (28-114%; p<0.0001). Significant improvement for the whole cohort was found regarding patients' pain, activity, mobility, shoulder flexion and abduction, and internal and external rotation (p<0.001). In one case, reoperation was necessary due to a superficial wound infection, and in another case, implant revision to a total shoulder replacement was performed because of glenoid erosion.

CONCLUSION

Cementless humeral surface replacement arthroplasty is a viable bone-preserving treatment option for young and active patients. Later conversion to total shoulder replacement is possible. Good clinical results, a low complication rate, and high patient satisfaction were found in the short and mid term. Long-term investigations are necessary to confirm these observations.

Mid-term survivorship analysis of a shoulder replacement with a keeled glenoid and a modern cementing technique

We have investigated the mid-term outcome of total shoulder replacement using a keeled cemented glenoid component and a modern cementing technique with regard to the causes of failure and loosening of the components. Between 1997 and 2003 we performed 96 total shoulder replacements on 88 patients, 24 men and 64 women with a mean age of 69.7 years (31 to 82). The minimum follow-up was five years and at the time of review 87 shoulders (77 patients) were examined at a mean follow-up of 89.1 months (60 to 127). Cumulative survival curves were generated with re-operations (accomplished and planned), survivorship of the proshesis, loosening of the glenoid (defined as tilt > 5 degrees or subsidence > 5 mm), the presence of radiolucent lines and a Constant score of < 30 as the endpoints. There were two re-operations not involving revision of the implants and the survival rate of the prosthesis was 100.0% for the follow-up period, with an absolute Constant score of > 30 as the endpoint the survival rate was 98%. Radiological glenoid loosening was 9% after five years, and 33% after nine years. There was an incidence of 8% of radiolucent lines in more than three of six zones in the immediate post-operative period, of 37.0% after the first year which increased to 87.0% after nine years. There was no correlation between the score of Boileau and the total Constant score at the latest follow-up, but there was correlation between glenoid loosening and pain (p = 0.001). We found that total shoulder replacement had an excellent mid-term survivorship and clinical outcome. The surgical and cementing techniques were related to the decrease in radiolucent lines around the glenoid compared with earlier studies. One concern, however, was the fact that radiolucent lines increased over time and there was a rate of glenoid loosening of 9% after five years and 33% after nine years. This suggests that the design of the glenoid component, and the implantation and cementing techniques may need further improvement.

Total shoulder replacement in young and middle-aged patients with glenohumeral osteoarthritis

Our aim in this prospective study was to evaluate the outcome of total shoulder replacement in the treatment of young and middle-aged active patients with primary glenohumeral osteoarthritis. We reviewed 21 patients (21 shoulders) with a mean age of 55 years (37 to 60). The mean follow-up was seven years (5 to 9). The same anatomical, third-generation, cemented implant had been used in all patients. All the patients were evaluated radiologically and clinically using the Constant and Murley score.

No patients required revision. In one a tear of the supraspinatus tendon occurred. Overall, 20 patients (95%) were either very satisfied (n = 18) or satisfied (n = 2) with the outcome. Significant differences (p < 0.0001) were found for all categories of the Constant and Murley score pre- and post-operatively. The mean Constant and Murley score increased from 24.1 points (10 to 45) to 64.5 points (39 to 93), and the relative score from 30.4% (11% to 50%) to 83% (54% to 116%). No clinical or radiological signs of loosening of the implant were seen.

For young and middle-aged patients with osteoarthritis, third-generation total shoulder replacement is a viable method of treatment with a low rate of complications and excellent results in the mid-term.

Key pinch in healthy adults: normative values

Intra-individual and inter-individual variations of key pinch strength were analysed in a standardised manner for healthy Caucasian adults (female n = 403; male n = 366) aged between 20 and 95 years. The mean strength was less in women (right 6.6 kg; left 6.1 kg) than in men (right 10.4 kg; left 9.7 kg). Independently of hand dominance or gender, the right side was about 7% stronger. Constitutional variables such as forearm length, forearm circumference and hand size showed a positive correlation with key pinch strength. Since the correlation between age and key pinch was similar in both genders, showing a continuous decrease of strength from the fifth decade of life on, key pinch seems independent from gender-specific hormonal changes. In conclusion, we recommend to side adjust measured values and to include information regarding constitutional characteristics for intra-individual comparison.

[Hemiarthroplasty or total shoulder replacement in glenohumeral osteoarthritis?]

Shoulder arthroplasty has proven to be a successful option in the treatment of glenohumeral osteoarthritis. Although introduced in the 1970s by Ch. Neer, resurfacing of the glenoid remains controversial. With regard to some single prospective studies total shoulder replacement (TSR) seems to be superior to humeral head replacement (HHR) in the treatment of concentric osteoarthritis. The current literature shows that TSR leads to a better shoulder function and less pain. The decision on whether to perform a TSR or HHR should be guided by the individual pathology. The final treatment should be reliable in terms of a better shoulder function, reduced pain, and good strength. The role of glenoid loosening in TSR and its impact on shoulder function in the long term remains uncertain and has to be clarified in the future.

Humeral head resurfacing for fixed anterior glenohumeral dislocation

The purpose of this prospective study was to describe cementless humeral surface replacement arthroplasty (CHSRA) as a bone preserving treatment option for patients with fixed anterior glenohumeral dislocation. Ten patients with post-traumatic fixed anterior glenohumeral dislocation underwent CHSRA with a mean follow-up of 24 months. All patients were evaluated clinically using the Constant score and with radiographs in two planes. There were two reoperations: one patient developed glenoid erosion and was revised and in another case redislocation occurred. Clinical or radiographical signs of implant loosening were not found. The humeral head centred in the glenoid in nine out of ten cases radiographically. The Constant score increased from 20 points preoperatively to 61 points postoperatively (p < 0.007). CHSRA is a viable treatment option for elderly patients with fixed anterior glenohumeral dislocation and bone defects of the humeral head. Good clinical results and a moderate complication rate were found in the short term.

Endoprothetik bei der Rotatorenmanschetten

The treatment of cuff tear arthropathy (CTA) of the shoulder is based on the patient's subjective complaints, functional deficits, and the treatment goals that result from both. Only in the second line is the radiologic morphology of joint destruction important for the surgeon's decision. Based on these aspects it is possible to discriminate three types of CTA that obviously have similar functional deficits and radiological characteristics. This symptom-based classification can offer decision guidelines for the choice of an appropriate joint replacement.For the most frequent, stable, and osteoarthritic type with pain during motion and a tolerably restricted active and passive range of motion (ROM) surface replacement or hemiarthroplasty can lead to reasonable results. In the unstable type with only minimal radiological changes of the humeral head and the chief complaint of severe restriction of active ROM and in some cases recurrent shoulder dislocations, hemiarthroplasty with a glenoid reconstruction shell or reversed prosthesis are promising. A reverse prosthesis is the implant of choice for the necrotic type of CTA with extensive destruction of the humeral head, the glenoid, and the adjacent bony structures.

Die Beugefähigkeit im Daumengrundgelenk des gesunden Erwachsenen

Metacarpophalangeal flexion of the thumb is known to be highly variable. To obtain normative values, active metacarpophalangeal flexion of the thumb was measured bilaterally in healthy Caucasian adults (female n = 403; male n = 366) in a standardized manner. Independent of gender, inter-individual variation was high, ranging between 16 degrees and 90 degrees and showing a continuous decrease with increasing age. Women showed a bigger range of motion than men but in both range of motion was higher on the left thumb (mean 1.4 degrees in women and mean 1.1 degrees in men). No influence of hand dominance was observed. Thus, the healthy contralateral side should be used as parameter of comparison.

[Long-term results of the anatomic stem "Euroform"]

PURPOSE

To date there is a lack of long-term results of anatomic hip stems in the literature. In this context we present our 10-year results with the hip stem "Euroform".

METHODS

In a retrospective cohort study 90% of the 51 stems implanted in our institute in the years 1993/94 51 stems were reexamined. Of them 39 were implanted cement-free while 11 were cemented.

RESULTS

After 10 to 12 years no revision surgery of the cement-free stems was necessary or performed because of stem problems, in one case of a cemented stem revision was done because of cup problems. The survival rate for the complete prostheses was 97.5% after 10 years and 92% after 12 years. The revision surgery was done for cup problems. The satisfaction rate was "1.9" (according to the German school ranking system), the Merle d'Aubigné score was "good" (>10 points). However, one problem was the high rate of PE deterioration which depended on the inclination.

CONCLUSION

Both the cemented and the cement-free forms of the "Euroform" stem gives good long-term results. The longevity of the prostheses is limited by polyethylene wear.

Influence of the design of the prosthesis on the outcome after hemiarthroplasty of the shoulder in displaced fractures of the head of the humerus

We reviewed 39 patients with displaced three- and four-part fractures of the humerus. In 21 patients (group A) we had used an anatomical prosthesis for the humeral head and in 18 (group B) an implant designed for fractures.

When followed up at a mean of 29.3 months after surgery the overall Constant score was 51.9 points; in group A it was 51.5 and in group B 52.4 points. The subjective satisfaction of the patients was assessed using a numerical rating scale and was similar in both groups. In group A complete healing of the tuberosities was found in 29% and 50% in group B. Partial integration was seen in 29% of group A and in only one patient in group B, while resorption was noted in 43% of group A and 44% of group B. The functional outcome was significantly better in patients with complete or partial healing of the tuberosities (p = 0.022). The specific trauma prosthesis did not lead to better healing of the tuberosities. The difference in clinical outcome obtained by the two designs did not reach statistical significance.