Differential effects of oxidised and non-oxidised polyethylene particles on human monocyte/macrophages in vitro

Immediate cementless hemiarthroplasty for severe destructive glenohumeral tuberculous arthritis

The glenohumeral joint tuberculosis (TB) is rare as compared with other joints. Plaster immobilization, arthrodesis, and resection arthroplasty have been proposed as the additional treatments with anti-TB medications in severe destructive arthritis. To our knowledge, however, the surgical treatment with shoulder arthroplasty has never been reported. We present two cases of active TB with unsalvageable glenohumeral joint. The cementless hemishoulder arthroplasties were performed immediately following the radical debridement. Anti-TB medications were given for 12 months after the surgery. Postoperatively, the patients were satisfied with the rapid symptomatic relief and significant functional recovery. With the follow-up period of 5 years, the operative results were still satisfactory and the reactivation of the infection was not detected.

Long-term outcome of shoulder arthrodesis performed with plate fixation: 18 patients examined after 3-15 years

BACKGROUND AND PURPOSE

There have been few reports on the long-term function after shoulder arthrodesis. We report the outcome after shoulder arthrodesis with plate fixation in 18 patients who were followed for 3-15 years.

METHODS

25 patients with a median age of 64 (19-75) years were operated with a shoulder arthrodesis between 1982 and 2003. Standard AO surgical technique with plating was used in all patients. 18 of the patients were examined retrospectively after a mean of 8 (3-15) years. 6 of the other patients had died and 1 refused examination.

RESULTS

Radiologically, all but two arthrodeses fused completely. The remaining two were partially fused, within the glenohumeral joint or between humerus and acromion. The mean Oxford shoulder score was 32 and the mean ASES shoulder index was 59. Nine patients had intermittent or continuous pain; their mean pain score on a visual analog scale was 3. One patient had been re-operated after 4 months because of severe pain and 1 was operated due to a humeral shaft fracture after 8 months. 1 patient suffered from a complex regional pain syndrome. No infections occurred.

INTERPRETATION

In this patient series there were few complications after shoulder arthrodesis, and the longterm functional results were acceptable.

Arthrodesis of the shoulder

Shoulder arthrodesis is an end-stage salvage option for the failing, painful joint that cannot undergo or has failed reconstruction. It is indicated for irreversible and nonreconstructible massive rotator cuff tears and deltoid muscle denervation as well as for detachment of the deltoid from its origin. Rarely, arthrodesis is done to stabilize the glenohumeral joint after many failed attempts at shoulder reconstruction. Arthrodesis for failed prosthetic arthroplasty or tumor resection presents additional challenges because of the associated bone loss on the humeral and/or glenoid side of the joint. Primary arthrodesis requires rigid internal plate fixation and both an extra- and an intra-articular site of fusion. Depending on bone volume and quality needed, the patient may require bracing for 8 to 10 weeks, autogenous or allograft bone grafting, or a vascularized fibular bone graft to reconstruct the bone deficiency, along with prolonged spica cast immobilization. The optimal position for arthrodesis is 20 degrees of forward flexion, 20 degrees of abduction, and 40 degrees of internal rotation, with modifications based on patient body size or other patient-specific factors. Bone fusion is attained in nearly all patients, with marked pain reduction and improved function. Postoperatively, the patient should be able to lift the arm to near shoulder height and to reach the top of the head, the mouth, the ipsilateral back pocket, and the groin. Complications include nonunion, malposition, pain associated with prominent hardware, and periarticular fractures.

Chemokine gene activation in human bone marrow-derived osteoblasts following exposure to particulate wear debris

Particulate wear debris induces the expression of pro-inflammatory cytokine and chemokine genes in various cell types of the periprosthetic region. We have previously reported that titanium particles stimulate the selective induction of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) chemokines in human osteoblast-like osteosarcoma cells. In this study, we characterize the human bone marrow-derived osteoblast chemokine response to titanium particles. We demonstrate that titanium particles result in enhanced IL-8 and MCP-1 protein secretion as well as differential chemokine gene activation. Osteoblast chemokine expression was regulated at the level of gene transcription, with a time-dependent induction of NF-kappaB activation. Inhibition studies with N-acetyl-L-cysteine (Nac) and MG-132 suggest that titanium particle activation of NF-kappaB activity and IL-8 chemokine expression involves oxidant signaling and IkappaBalpha-proteasomal degradation. Activation of the NF-kappaB transcription factor, as well as the IL-8 gene, are redox-regulated. We also demonstrate that while cytochalasin D, a potent inhibitor of phagocytosis, suppressed the titanium particle effect on IL-8 protein release in human bone marrow-derived osteoblasts, the inhibitor had no effect on IL-8 expression in MG-63 osteoblast-like cells. Collectively, these results provide insight into the potential mechanisms responsible for the particulate activation of osteoblast chemokine expression and suggest an important role for the osteoblast in the pathogenesis of periprosthetic osteolysis.

Significance of shoulder function in the reconstruction of prehension with double free-muscle transfer after complete paralysis of the brachial plexus

Reconstruction of shoulder stability and movement in cases with complete paralysis of the brachial plexus was performed to improve the outcomes for universal function of prehension after double free-muscle transfer (Doi's procedure). In cases in which the C5 or C6 nerve root was available as a donor, neurotization of the supra-scapular nerve was performed with a nerve graft. If the C5 or C6 nerve root was not available, then the contralateral C7 nerve root was chosen as the donor motor nerve and was transferred to the suprascapular nerve by using a vascularized ulnar nerve graft. Seven cases with ipsilateral C4, C5, or C6 nerve root transfer to the suprascapular nerve and one with contralateral C7 transfer were evaluated, and the functional outcomes for the range of shoulder motion were compared with those for patients who had undergone arthrodesis of the humeroscapular joint or had undergone no procedures for shoulder function reconstruction. The patients who underwent supra-scapular nerve repair demonstrated statistically significantly better ranges of motion for flexion and abduction of the shoulder, compared with the other two groups. Shoulder function is important for achieving prehensile function among patients with complete paralysis of brachial function, when they undergo double free-muscle transfer.

Effect of pamidronate on the stimulation of macrophage TNF-alpha release by ultra-high-molecular-weight polyethylene particles: a role for apoptosis

The demonstration that one of the mechanisms of action of bisphosphonates (BPs) is the induction of osteoclast and macrophage apoptosis, suggests a potent therapeutic role for the BPs and other apoptosis-modulating agents in the management of periprosthetic osteolysis. The purpose of this study was to improve our understanding of the basic underlying molecular events leading to the inhibitory effect of pamidronate on the macrophage response to ultra-high-molecular-weight polyethylene (UHMWPE) particles. Murine J774 macrophages were incubated for 0-72 h in the presence of UHMWPE particles and/or pamidronate. TNF-alpha release was measured by ELISA while poly(ADP-ribose)polymerase (PARP) expression was measured by Western blot. DNA was analyzed on agarose. The appearance of PARP fragment and the fragmentation of DNA were used as markers of apoptosis. We observed a dose-dependent response to UHMWPE particles with TNF-alpha release reaching 4, 10, and 19 times control with 10, 25, and 125 particles/macrophage, respectively. UHMWPE particles (25 particles/macrophage) stimulate TNF-alpha release by a factor of 10, 7, and 6 after 24, 48, and 72 h, respectively, indicating a rapid stimulating effect of UHMWPE particles on TNF-alpha release. Our results also showed that at 10 particles/macrophage, pamidronate inhibits UHMWPE-induced TNF-alpha release by 12%, 14%, and 23% respectively after 24, 48, and 72 h (p<0.05 vs. 24 and 48 h). With 25 particles/macrophage, the inhibition of TNF-alpha reached 9%, 12%, and 15% after 24, 48, and 72 h (p<0.05 vs. 24 h), respectively. There is no significant difference between the inhibition by pamidronate of TNF-alpha release induced by 125 particles/macrophages at 24, 48, and 72 h. When cells are pre-incubated for 48 h with pamidronate prior to addition of UHMWPE particles for 24 h, we observed an increased inhibition of TNF-alpha compared to the co-incubation protocol. The inhibiting effect of pamidronate reaches 56% when pre-incubated with macrophages prior to incubation with 10 particles of UHMWPE/macrophage (p<0.05 vs. co-incubation).Co-incubation of pamidronate with UHMWPE particles also led to the appearance of the proteolytic PARP fragment after 24 h incubation. We also demonstrated the stimulation of DNA fragmentation (DNA laddering) after 48-72 h with pamidronate. The proteolytic cleavage of PARP, an early event in the induction of apoptosis, precedes the inhibition of UHMWPE particle-induced TNF-alpha release by pamidronate whereas the fragmentation of DNA, a late apoptotic event, parallels this inhibition. Our results suggest the induction of macrophage apoptosis is associated with the inhibitory effect of pamidronate on TNF-alpha release. There is a need for the development of medical management of periprosthetic osteolysis. The demonstration that drugs such as pamidronate induce specific apoptosis-related pathways in macrophages contributes data for a rational approach in the treatment and/or prevention of periprosthetic osteolysis.