Hydroxyapatite-coated collars reduce radiolucent line progression in cemented distal femoral bone tumor implants.

BACKGROUND: Aseptic loosening of massive bone tumor implants is a major cause of prosthesis failure. Evidence suggests that an osteointegrated hydroxyapatite (HA)-coated collar would reduce the incidence of aseptic loosening around the cemented intramedullary stem in distal femoral bone tumor prostheses. Because these implants often are used in young patients with a tumor, such treatment might extend the longevity of tumor implants. Questions/purposes We asked whether (1) HA-coated collars were more likely to osteointegrate; (2) HA collars were associated with fewer progressive radiolucent lines around the stem-cement interface; and (3) HA-coated collars were associated with less bone loss at the bone-shoulder implant junction? METHODS: Twenty-two patients were pair-matched to one of two groups--either (1) implants with a HA-coated ingrowth collar (HA Collar Group); or (2) implants without an ingrowth collar (Noncollar Group). Age, sex, and length of followup were similar in both groups. HA-coated collars were developed and used at our institution from 1992 to address the high failure rate attributable to aseptic loosening in patients with massive bone tumor implants. Before this, smooth titanium shafts were used routinely adjacent to bone at the transection site. The minimum followup was 2 years (mean, 7 years; range, 2-12 years). Radiographs obtained throughout the followup period were analyzed and osteointegration at the shaft of the implant quantified. Radiolucent line progression around the cemented stem was semi-quantitatively assessed and cortical bone loss at the bone-shoulder implant junction was measured during the followup period. RESULTS: Comparison of the most recent radiographs showed nine of 11 patients had osteointegrated HA collars, whereas only one patient in the Noncollar Group had osteointegration (p > 0.001). The radiolucent line score quantified around the cemented stem was lower in the HA Collar Group when compared with the Noncollar Group (p = 0.001). Results showed an increase in cortical bone loss at the bone-shoulder implant junction in the Noncollar Group when compared with the HA Collar Group (p < 0.001). CONCLUSIONS: Osteointegration at the implant collar resulted in fewer radiolucent lines adjacent to the intramedullary cemented stem and decreased cortical bone loss immediately adjacent to the transection site. These results suggest that the HA collar may help reduce the risk of aseptic loosening in patients with this type of implant, but longer followup and a larger prospective comparison series are necessary to prove this more definitively.

Proximal ulna endoprosthetic replacement for bone tumours in young patients.

PURPOSE: The optimal reconstructive method after resection of malignant bone tumours of the proximal ulna is unknown.We report the outcome of endoprosthetic replacement in a young patient population. METHODS: This was a retrospective review of four patients[three males and one female; mean age 17.5 (range 11­31)years] who underwent limb salvage with a proximal ulnar endoprosthetic replacement following excision of malignant bone tumour. Mean follow-up was 85 (range 14­194) months. RESULTS: All patients were alive at final follow-up and reported an improvement in pain. One patient required transhumeral amputation for intralesional excision complicating a local recurrence at one month. Two patients developed fixed flexion deformities of the elbow, one of whom required radial-head excision. Mean Musculoskeletal Tumour Society (MSTS)score and Toronto Extremity Salvage Score (TESS) were 27(range 25­28) and 81 (73­88), respectively. CONCLUSIONS: Custom-made proximal ulna endoprosthetic replacement following resection of malignant bone tumours in young patients provides a stable reconstruction option with satisfactory function and without apparent compromise in patient survival.

Custom cementless THA in patients with skeletal dysplasia results in lower apparent revision rates than other types of femoral fixation.

BACKGROUND: Patients with skeletal dysplasia are prone to degenerative hip disease thus requiring THA at a younger age than the general population. This is a technically demanding procedure with high complication and revision rates. Achieving good femoral fixation can be challenging because of the abnormal features of the hip. QUESTIONS/PURPOSES: We therefore determined: (1) survivorship, (2) function, (3) radiographic findings, and (4) complications associated with a cementless custom-made femoral component used in THAs for patients with skeletal dysplasia and compared these parameters with those from other types of femoral fixation. PATIENTS AND METHODS: Between 1992 and 2005, 40 THAs were performed in 25 patients with skeletal dysplasia using custom-made cementless femoral components. There were 15 men and 10 women with a mean age of 37.5 years (range, 18-61 years) and a mean height of 145 cm (range, 120-173 cm). Patients were followed clinically and radiographically for a minimum of 4.3 years (mean, 10.1 years; range, 4.3-18.2 years). RESULTS: The survivorship rates for the femoral and acetabular components were 92% and 70%, respectively, at 220 months. Revision arthroplasty was performed in four of 40 hips (10%). In two, the acetabular component was revised for aseptic loosening, one had both components revised for aseptic loosening, and one had an isolated femoral component revision for deep infection. The mean Harris hip score improved from 41 (range, 27-57) preoperatively to 80 (range, 51-94) at final followup. There were two intraoperative proximal femoral fractures and one dislocation. CONCLUSIONS: When compared with studies with equal followup, custom-made cementless components in THAs for patients with skeletal dysplasia apparently had lower revision and complication rates with comparable function and higher midterm survival.

The use of a novel "conservative hip replacement" to reconstruct an osteoarthritic hip with an occluded femoral canal.

This case report describes the successful use of a novel "conservative hip replacement" in conditions precluding the use of a standard total hip arthroplasty in a 70-year-old man. The femoral canal was occluded because of previous surgery for a bone tumor in the subtrochanteric region. The patient continues to do well at 4 years with minimal discomfort. At this interval, the Oxford Hip Score was 35. This conservative hip replacement has been developed to preserve bone stock and produce more physiologic loading of the proximal femur. Its design has been produced, using plain radiographs and computed tomography, to maximize "fit and fill" of the femur. The neck supports standard modular heads, allowing the use of any bearing surface. The prosthesis has been rigorously laboratory tested.

Custom endoprosthetic reconstruction for malignant bone disease in the humeral diaphysis.

The optimal reconstructive method following segmental resection of malignant tumours in the humeral diaphysis is unknown as there are no prospective long-term studies comparing biologic with endoprosthetic reconstruction. This is a retrospective review of 13 patients who, between 1995 and 2010, had undergone limb salvage at our institution using a custom-made humeral diaphyseal endoprosthetic replacement following excision of malignant bone disease. There were 9 males and 4 females with a mean age of 35 years at the time of surgery (range: 10 to 78). Mean follow-up was 56.8 months (range: 5 to 148). Cumulative patient survival was 75% at 10 years. Implant survival, with removal of the endoprosthesis or part of it for any reason as an end point, was 47% at 10 years. Seven patients required revision (54%). Complications included metastases in four, aseptic loosening in four, peri-prosthetic fracture in two and local recurrence in two. Mean MSTS and TESS scores were 23 (18 to 27) and 67% (52-80) respectively. Custom-made humeral diaphyseal replacement following resection of malignant bone tumours provided functional results superior to amputation, without an obvious compromise in patient survival. There was a relatively high revision rate for aseptic loosening and peri-prosthetic fracture and patients should be counselled about this preoperatively.

Proximal femoral replacements for metastatic bone disease: financial implications for sarcoma units.

Metastatic pathological fractures of the proximal femur are increasingly treated by endoprosthetic proximal femoral replacement. We report the results and the costs incurred performing these procedures at our supra-regional sarcoma unit. Sixty-two patients underwent 63 proximal femoral replacements for metastatic bone disease over a seven-year period. Breast cancer was the most common primary pathology. One patient underwent a revision procedure for infection. Twenty-two patients suffered dislocations, most commonly those undergoing a conventional arthroplasty articulation. The estimated cost of a proximal femoral replacement is 18,002 pounds at our centre. Less than half of this is reimbursed under Payment by Results. Endoprosthetic replacement of the proximal femur is an effective treatment of metastases, but is poorly reimbursed under current funding arrangements.

Modular proximal femoral replacement in salvage hip surgery for non-neoplastic conditions.

Addressing severe proximal femoral bone loss in revision hip surgery is a challenging reconstructive problem. The use of modular proximal femoral megaprostheses is one of many available options to address this. This is a retrospective review of 15 patients who had undergone limb salvage at our institution using a modular proximal femoral replacement. There were 8 males and 7 females with a mean age of 67 years (34 to 85) and a mean follow-up of 60 months (1 to 99). Indications included re-implantation for deep infection in nine patients, aseptic loosening in three, periprosthetic fracture in two and painful excision arthroplasty in one. Mean Harris hip score increased from 28 (13 to 49) pre-operatively to 69 (39 to 85) at final follow-up (paired t-test, p < 0.0001) and mean Toronto Extremity Salvage score increased from 26% (14 to 40) to 71% (35 to 82) (paired t-test, p < 0.0001). Prosthesis survival with revision as the endpoint was 87% at 5 years. There were two dislocations (14%) and there was failure to eradicate deep infection in two. Modular proximal femoral replacement provided good function and versatility with an acceptable complication rate for patients with severe proximal femoral bone loss with or without infection.

Immune responses in patients with metal-on-metal hip articulations: a long-term follow-up.

Metal-on-metal (MoM) hip bearings are being inserted into ever-younger patients. The effects on the immune system of chronic exposure are unknown. We investigated the immune response of patients with MoM hip bearings. In patients with MoM implants, the expression of antigen-presenting cell (APC) surface molecules (CD86 and HLA-DR) was seen to be significantly higher (P < .05) than control group. High levels of APC surface molecules suggest an activated state and attempts to propagate an immune response. However, in the same group, the expression of T-cell markers (CD3 and CD28) was low, indicating a small T-cell population. This suggests, despite the activation of APCs, that T cells down-regulate immune responses in MoM articulations. Conversely, in metal-on-polyethylene articulations, expression of T-cell molecules was elevated and expression of APC molecules lowered.

Custom-made endoprosthetic reconstruction of the distal humerus for non-tumorous pathology.

Eight patients underwent custom-made endoprosthetic elbow reconstruction between 1989 and 2006 either for failed primary total elbow replacements or following complex fracture complications. A functional assessment using the Toronto Extremity Salvage (TES) score was performed. Patients were followed for a mean of 46.1 months (range : 25 to 88). One patient who presented with an infected periprosthetic fracture around a total elbow replacement, failed two-stage reconstruction and underwent excision arthroplasty. The remaining seven patients were available for functional follow-up. Average flexion deformity was 15 degrees (range: 7 to 35) and average flexion arc was 85 degrees (range : 70 to 130). The mean TES score was 67.3 (range: 36.6 to 95.9). Custom made endoprosthetic reconstruction allowed for a satisfactory outcome in all but one of these eight patients with severe bony destruction around the elbow in the absence of tumour infiltration.

Use of a novel bone graft substitute in peri-articular bone tumours of the knee.

We treated three patients with aneurysmal bone cysts and seven with giant cell tumours who presented with a large osteolytic lesion in peri-articular areas of the knee. The patients age ranged from 8 to 49 years (mean 25 years). The average tumour volume was measured at 39.8 cm(3) (range 18 to 65 cm(3)). The tumour cavities were treated with curettage, phenolisation and application of a composite bone graft substitute containing 35% calcium-sulphate hemihydrate and 65% hydroxyapatite granules. All patients were followed up for 4.0 to 5.2 years (mean 4.5 years). Tumour recurrence was noted in two cases. In the remaining patients consolidation of the lesion was considered complete at a mean of 4.5 months (3-6.5 months). During follow-up no deformities developed and no radiological signs of joint degeneration were noted. All patients regained close to normal function, with a mean Musculoskeletal Tumour Society Rating Score of 95.1%. Due to their good osteoconductive abilities, composite synthetic bone graft substitute combining porous hydroxyapatite with calcium-sulphate appears to be an effective alternative to autologous cancellous bone graft in the treatment of large osteolytic lesions in peri-articular areas around the knee joint. They bear major advantages through ubiquitous availability and the avoidance of morbidity associated with iliac crest harvest. Concerns remain as the radio-opaque appearance of the bone graft substitute may potentially delay the detection of tumour recurrence.

The tactics and technique of musculoskeletal biopsy.

The treatment of musculoskeletal neoplasms and infection is usually based on an initial diagnostic biopsy.Prior to biopsy, a hypothesis should be formed about the most likely diagnosis and a differential diagnosis. These deliberations should consider whether the lesion is a primary benign or malignant tumour, a metastasis, a haematological problem or an infection.A tactical plan should be developed which evaluates the necessity, the risk, the approach and finally defines the technique of biopsy most likely to achieve a representative result in the clinical case.In developing this technical approach, the pitfalls should be anticipated, i.e. inadequate sampling, difficulty of pathological interpretation and contamination.The tactical approach should be developed in conjunction with a multi-disciplinary team together with appropriate pre-biopsy imaging. Cite this article: EFORT Open Rev 2017;2:51-57. DOI: 10.1302/2058-5241.2.160065.

Characterisation of cryopreserved cells freshly isolated from human bone marrow.

Osteoblast progenitor cells (OBPCs) isolated from bone marrow have the ability to differentiate into osteoblasts and thus potential therapeutic use to tissue-engineer bone. In order for OBPCs to be available for clinical use a means of storing viable cells is necessary. The aim of this study was to determine whether a simple method of cryopreservation had an effect on osteogenic differentiation or growth of OBPCs isolated from fresh human bone marrow. Stro-1 was used to identify the isolated OBPCs. The osteoblastic potential of the marrow cells was confirmed as culture with osteogenic supplements (OS) significantly increased osteoblastic protein production (alkaline phosphatase (ALP), osteopontin and osteocalcin) compared with standard conditions (P less than 0.05). Ten further marrow aspirates were harvested; each was halved for either cryopreservation or control culture. Primary cultures from both populations formed colonies with recognised OBPC morphology. OS stimulated both cryopreserved and control populations to produce significantly more osteoblastic proteins (P less than 0.05) and there was no significant difference between the increase in osteogenic proteins when cultured with OS (P great than 0.2). The proliferation rate after 5 days in culture was not significantly affected by cryopreservation (P greater than 0.05). It has been suggested that OBPCs are immuno-privileged; so allogenic cells could be implanted into patients for tissue engineering bone without causing a hypersensitivity reaction. Our study demonstrates a method of storage, which allows OBPCs to be available for use without affecting osteoblastic potential or viability.

Periosteal osteosarcoma--a European review of outcome.

Periosteal osteosarcoma is a rare primary malignant bone tumour. Treatment is by surgical excision, but controversy remains about the value of chemotherapy. The members of the European Musculo Skeletal Oncology Society (EMSOS) collaborated to produce a dataset of 119 patients. The predominant site for the tumour was the femur, followed by the tibia. All but 2 patients underwent surgery, with 9 requiring amputation and the others having limb salvage. A total of 81 patients had chemotherapy, of whom 50 had neoadjuvant chemotherapy. There was no standard chemotherapy regime, but all patients receiving chemotherapy were given doxorubicin combined with at least one other agent. The overall survival was 89% at 5 years and 83% at 10 years. Eight patients developed local recurrence, of whom 5 died. Survival was related to appearance of local recurrence (P < 0.0001) but no other single factor. The use of chemotherapy was not shown to be a prognostic factor, but was used in two-thirds of the patients in this study.

The octogenarian total knee arthroplasty.

Sixty-five patients aged > 80 years were compared to 65 patients aged between 60 and 70 years to assess total knee arthroplasty (TKA) outcome using the octogenarian postoperative Knee Society knee and function scores. Knee Society knee scores showed excellent outcomes with no statistically significant difference in the younger cohort (preoperative score, P = .7156; 5-year score, P = -.0677). Knee Society function scores also showed good outcomes with no statistically significant difference between the groups (preoperative score, P = .1147; 5-year score, P = .1348). Average length of stay increased by 3 days for octogenarians. Octogenarians had more pre-existing medical conditions and suffered more postoperative confusion. All but 1 patient rated the result as good/excellent. Patients maintained their independence for approximately 3.5 years before requiring more social input. With careful preoperative planning and counseling, TKA is recommended for the octogenarian.

Long-term survival of cemented distal femoral endoprostheses with a hydroxyapatite-coated collar: a histological study and a radiographic follow-up.

BACKGROUND: The objective of this study was to examine the degree of osteointegration into a hydroxyapatite-coated collar and relate this finding to aseptic loosening in patients with a distal femoral replacement used to treat primary bone cancer. Our hypothesis was that the implant collar would increase osteointegration and reduce the rate of aseptic implant loosening. METHODS: Sixty-one patients treated with a primary cemented distal femoral prosthesis between 1992 and 2001 were included in this study. The mean duration of follow-up was 8.5 years (range, two to eighteen years). Extracortical bone growth into the grooved hydroxyapatite-coated collar was quantified radiographically. Histological sections through four hydroxyapatite-coated collars and four implants with no collar, retrieved following amputation due to local recurrence or at autopsy at a mean of 3.5 years (range, 1.4 to 6.1 years) after implantation, were evaluated as well. RESULTS: Five (8%) of the implants were revised because of aseptic loosening, 3% of the implants fractured, and 3% were revised because of infection. Six limbs (10%) required amputation because of local tumor recurrence. On radiographs, osteointegration into the collar was seen to have occurred in 70% of the patients and did not correlate with sex, age, diagnosis, or length of time postoperatively. Histological analysis showed mature lamellar bone within the grooves of the hydroxyapatite-coated collar, and bone was observed in direct contact with the hydroxyapatite coating. Extracortical bone failed to make direct contact with the surface of the implants manufactured without a collar. CONCLUSIONS: The use of cemented distal femoral massive bone tumor prostheses with a hydroxyapatite-coated collar located at the shoulder of the implant was followed by a low (8%) rate of revision due to aseptic loosening. The use of hydroxyapatite grooved collars may lead to osteointegration of the implant shoulder (collar) and may reduce the rate of aseptic loosening.

Delayed sciatic nerve palsy following resurfacing hip arthroplasty caused by metal debris.

The rapid rise in the incidence of failed metal-on-metal hip articulations in recent years has led to many patients requiring complex revision surgery. These failed metal prostheses may produce local metallic debris, which promotes both local and systemic adverse effects. We report an unusual case of failed metal-on-metal resurfacing hip arthroplasty presenting with ipsilateral buttock pain and foot drop 6 months after surgery. After thorough investigations, the metal-on-metal bearing was revised to a metal-on-polyethylene total hip replacement. This resulted in marked improvement in the systemic symptoms, inflammatory marke and metal ion levels postoperatively. However, neither clinical nor neurophysiological sciatic nerve recovery followed. The patient eventually required tendon transfer surgery for her persistent foot drop.

A common single-nucleotide variant in T is strongly associated with chordoma.

Chordoma is a rare malignant bone tumor that expresses the transcription factor T. We conducted an association study of 40 individuals with chordoma and 358 ancestry-matched controls, with replication in an independent cohort. Whole-exome and Sanger sequencing of T exons showed strong association of the common nonsynonymous SNP rs2305089 with chordoma risk (allelic odds ratio (OR) = 6.1, 95% confidence interval (CI) = 3.1-12.1; P = 4.4 × 10(-9)), a finding that is exceptional in cancers with a non-Mendelian mode of inheritance.

Use of irradiated autologous bone in joint sparing endoprosthetic femoral replacement tumor surgery.

BACKGROUND: Joint preservation is usually attempted in cases of bone tumors, though insufficient bone following tumour resection may prevent fixation of conventional joint sparing prosthesis. To preserve the hip joint in skeletally immature patients, we have combined autologous proximal femoral irradiation and intercalary re-implantation with custom made distal femoral replacements. MATERIALS AND METHODS: A retrospective cohort study of four patients (aged 4-12 years); in whom irradiated autologous bone was combined with an extendable distal femoral endoprostheses was performed. There were three cases of osteosarcoma and one case of Ewing's sarcoma. RESULTS: At a mean follow-up of 70.5 months (range 26-185 months), all four patients were alive without evidence of local recurrence. There was no evidence of metastatic disease in three patients while one patient showed chest metastatic disease at presentation. In all cases, the irradiated segment of bone united with the proximal femur and demonstrated bone ongrowth at the prosthetic collar. There were no cases of loosening or peri-prosthetic fracture. One implant was revised after 14 years following fracture of the extending component of the endoprosthesis. CONCLUSIONS: We report encouraging results utilizing irradiated autologous proximal femoral bone combined with distal femoral replacement in skeletally immature patients.

Synovial chondromatosis of the foot presenting with Lisfranc dislocation.

Primary synovial chondromatosis is rare in the foot. We report a case of synovial chondromatosis affecting multiple sites of the foot and causing bone erosions in a 44-year-old woman. Radiographs demonstrated erosions of multiple metatarsals including the tarsometatarsal joints, resulting in Lisfranc tarsometatarsal dislocation. Magnetic resonance imaging showed the widespread synovial proliferation and soft tissue masses affecting the foot and helped in arriving at a differential diagnosis and plan for needle biopsy. Diagnosis was made initially by needle biopsy under computed tomography guidance and was subsequently confirmed by histopathological assessment of the surgically excised synovial masses. To our knowledge, multifocal synovial chondromatosis causing Lisfranc dislocation in the foot has not been reported previously.