Introduction

Autologous chondrocyte implantation (ACI) is contra-indicated in a joint rendered unstable by a ruptured anterior cruciate ligament (ACL). We present our experience of ACI repair with ACL reconstruction

It is known that excessive varus alignment of the femoral stem in total hip replacement (THR) creates a sub-optimal biomechanical environment which is associated with increased rates of revision surgery and component wear. Little is known regarding the effect of femoral stem alignment on patient functional outcome.

Hyaline cartilage defects are a significant clinical problem for which a plethora of cartilage repair techniques are used. One such technique is cartilage replacement therapy using autologous chondrocyte or mesenchymal stem cell (MSC) implantation (ACI). Mesenchymal stem cells are increasingly being used for these types of repair technique because they are relatively easy to obtain and can be expanded to generate millions of cells. However, implanted MSCs can terminally differentiate and produce osteogenic tissue which is highly undesirable, also, MSCs generally only produce fibrocartilage which does not make biomechanically resilient repair tissue, an attribute that is crucial in high weight-bearing areas. Tissue-specific adult stem cells would be ideal candidates to fill the void, and as we have shown previously in animal model systems [Dowthwaite et al, 2004, J Cell Sci 117;889], they can be expanded to generate hundreds of millions of cells, produce hyaline cartilage and they have a restricted differential potential. Articular chondroprogenitors do not readily terminally differentiate down the osteogenic lineage.

At present, research focused on isolating tissue-specific stem cells from articular cartilage has met with modest success. Our results demonstrate that using differential adhesion it is possible to easily isolate articular cartilage progenitor populations from human hyaline cartilage and that these cells can be subsequently expanded in vitro to a high population doubling whilst maintaining a normal karyotype. Articular cartilage progenitors maintain telomerase activity and telomere length that are a characteristic of progenitor/stem cells and differentiate to produce hyaline cartilage.

In conclusion, we propose the identification and characterisation of a novel articular cartilage progenitor population, resident in human cartilage, which will greatly benefit future cell-based cartilage repair therapies.

Articular cartilage implantation (ACI) and associated procedures (MACI = Matrix-assisted cartilage implantation) are now established treatments for osteochondral defects in the knee. The quality of repair in terms of histological appearance is frequently not known, whilst the correlation of histology results with functional outcomes remains undefined. Histological data of the quality of the repair tissue is sparse and a precise classification proved difficult.

This was a single-centre, prospective study. Over 12 years (1998-2010) 406 patients that underwent articular cartilage implantation procedures at our institution (ACI = 170, MACI = 205) had biopsies taken at the 1-2 year interval, in order to assess whether these contained ‘hyaline-like’ cartilage, ‘mixed hyaline-like with fibrocartilage’, fibrocartilage or fibrous tissue alone.

Histological sections of the biopsies were prepared and stained with haematoxylin, eosin and proteoglycan stains and viewed under polarised light. All biopsies were studied by a single histopathologist in a specialist, dedicated musculoskeletal laboratory.

All patients were assessed by the Cincinnati, Bentley and Visual Analogue scores both pre-operatively and at the time of the review.

The findings revealed that 56 patients healed with ‘hyaline-like’ cartilage (14.9%), 103 with ‘mixed’ (27.5%), 179 with fibrocartilage (47.7%) and 37 with fibrous tissue (9.9%).

These findings showed that 42.4% of defects were filled with ‘hyaline-like’ or ‘mixed’ cartilage, with 70% of these achieving a ‘fair’ to ‘excellent’ functional outcome. This was also observed in the fibrocartilage group, where 72% achieved similar results. Predictably 89% of the patients that healed by fibrous tissue had a poor functional outcome.

This study shows that 71% of patients whose osteochondral defects healed by either ‘hyaline-like’, ‘mixed’ or fibrocartilage experienced an improvement in the function. In contrast, only 11% of the patients whose defects filled with fibrous tissue, showed some functional improvement. Additionally, this data indicates the advantage of biopsies in assessing the overall results of cartilage implantation procedures.

Introduction

Following bone tumour resection, lower limb reconstruction results in leg-length discrepancy in skeletally immature patients. Previously, minimally invasive endoprostheses have been associated with a high risk of complications including joint stiffness, nerve injury, aseptic loosening and infection. The purpose of this study was to examine the outcome of the Stanmore non-invasive extendible endoprostheses used in our institution between 2002 and 2009 and compare them with implants used in the past.

Introduction

The proximity of the superior tibiofibular articulation to neurovascular structures makes the management of extraosseous tumours of the proximal fibula challenging in bone tumour surgery. The aim of study is to establish whether the recurrence rates are higher in this anatomical area compared to data that already exists in publication for bone tumours throughout the appendicular skeleton.

It is generally accepted that there is a high rate of local recurrence following surgical excision of chordoma of the sacrum, even if the margins of excision appear clear. There is uncertainty as to whether the addition of postoperative radiotherapy may decrease the risk of local recurrence, particularly if there are close or involved margins. We aimed to determine the effect of conventional radiotherapy, in the post-operative setting, on the effect of local recurrence, metastases and patient survival in a multi-centre study.

Sixty eight consecutive patients underwent proximal humeral replacement with a fixed fulcrum massive endoprosthesis for tumour between 1997 and 2007. The mean age was 46 years (7-87). Ten patients were lost to follow up and 16 patients died. The 42 surviving patients were assessed using the Musculoskeletal Tumour Society (MSTS) Score and the Toronto Extremity Salvage Score (TESS). The mean MSTS score was 72.3 % and the mean TESS was 77.2 %.

Four of 42 patients received a new constrained humeral liner to reduce the risk of dislocation. This sub group of 4 patients had a mean MSTS score of 77.7 % and a mean TESS of 80.0%.

Endoprosthetic replacement for tumour of the proximal humerus using this prosthesis is a reliable operation yielding good functional results without the documented problems of unconstrained prostheses. The performance of this prosthesis is expected to improve further with the new constrained humeral liner.

Introduction

Primary bone tumours of the distal radius are rare, while it remains the third commonest site for primary lesions and recurrences of Giant Cell Tumours (GCT). The functional demands on the hand make reconstruction of the wrist joint following the excision of distal radius, particularly challenging.

Hyaline cartilage defects are a significant clinical problem for which a plethora of cartilage repair techniques are used. One such technique is cartilage replacement therapy using autologous chondrocyte or mesenchymal stem cell (MSC) implantation (ACI). Mesenchymal stem cells are increasingly being used for these types of repair technique because they are relatively easy to obtain and can be expanded to generate millions of cells. However, implanted MSCs can terminally differentiate and produce osteogenic tissue which is highly undesirable, also, MSCs generally only produce fibrocartilage which does not make biomechanically resilient repair tissue, an attribute that is crucial in high weight-bearing areas. Tissue-specific adult stem cells would be ideal candidates to fill the void, and as we have shown previously in animal model systems [Dowthwaite et al, 2004, J Cell Sci 117;889], they can be expanded to generate hundreds of millions of cells, produce hyaline cartilage and they have a restricted differential potential. Articular chondroprogenitors do not readily terminally differentiate down the osteogenic lineage.

At present, research focused on isolating tissue-specific stem cells from articular cartilage has met with modest success. Our results demonstrate that using differential adhesion it is possible to easily isolate articular cartilage progenitor populations from human hyaline cartilage and that these cells can be subsequently expanded in vitro to a high population doubling whilst maintaining a normal karyotype. Articular cartilage progenitors maintain telomerase activity and telomere length that are a characteristic of progenitor/stem cells and differentiate to produce hyaline cartilage.

In conclusion, we propose the identification and characterisation of a novel articular cartilage progenitor population, resident in human cartilage, which will greatly benefit future cell-based cartilage repair therapies.

Orthopaedic problems are common in patients with Ehlers-Danlos Syndrome (EDS). Articular hypermobility can be particularly disabling leading to instability in the appendicular skeleton. We present a case of an EDS patient presenting with knee pain and instability. It highlights important lessons to be learned when considering joint replacement in this patient group.

A 51 year old lady with EDS underwent a posterior cruciate retaining total knee replacement for pain and instability. She dislocated her knee replacement three months post-operatively after a fall. Her knee was reduced at her local emergency department causing injury to the popliteal artery. She required urgent popliteal artery repair and fasciotomies. The common peroneal nerve was also irreversibly damaged by the dislocation. She has since had one further dislocation and is now awaiting revision surgery. When considering total knee replacement (TKR) in EDS, the patient must be warned of the inferior results compared to TKR for other causes. The increased risk of complications must be explained and a more constrained TKR design considered to address the inherent joint laxity. The potential consequences of a dislocated TKR can be disastrous and therefore relocation must be performed in a controlled environment in the operating theatre.

Patients with osteochondrodysplasia frequently require Total Hip Arthroplasty at a younger age, as a result of early degenerative disease of the hip joint. The outcome of Modular Total Hip Arthroplasty in this group of patients has been reported previously. In this retrospective study we evaluated the outcome of custom made (CADCAM) Total Hip Arthroplasty in patients with osteochondrodysplasia.

Between 1974 and 2009, twenty one CADCAM Total Hip Arthroplasty procedures were performed in fourteen patients in our institution. There were eight female and six male patients, with the mean age at time of surgery of 40.95 years (20 to 78). The patients were followed up clinically and with the Harris hip score for a mean of 7.12 years (0.5 to 17 years).

Four of the twenty-one hips (23.8%) required revision surgery at a mean of 11.54 years (6.5 to 17 years); one required it for aseptic loosening of the femoral component; one required complete revision of the acetabular component; one required exchange of acetabular liner; and one was for symptomatic non-union of a lesser trochanter avulsion.

This study shows encouraging clinical outcomes of custom made (CADCAM) Total Hip Arthroplasty in patients with osteochondrodysplasia,

Non-invasive expandable prostheses for limb salvage tumour surgery were first used in 2002. These implants allow ongoing lengthening of the operated limb to maintain limb-length equality and function while avoiding unnecessary repeat surgeries and the phenomenon of anniversary operations.

A large series of skeletally immature patients have been treated with these implants at the two leading orthopaedic oncology centres in England (Royal National Orthopaedic Hospital, Stanmore, and Royal Orthopaedic Hospital, Birmingham).

An up to date review of these patients has been made, documenting the relevant diagnoses, sites of tumour and types of implant used. 87 patients were assessed, with an age range of 5 to 17 years and follow up range of up to 88 months.

Primary diagnosis was osteosarcoma, followed by Ewing's sarcoma. We implanted distal femoral, proximal femoral, total femoral and proximal tibial prostheses. All implants involving the knee joint used a rotating hinge knee. 6 implants reached maximum length and were revised. 8 implants had issues with lengthening but only 4 of these were identified as being due to failure of the lengthening mechanism and were revised successfully. Deep infection was limited to 5% of patients.

Overall satisfaction was high with the patients avoiding operative lengthening and tolerating the non-invasive lengthenings well. Combined with satisfactory survivorship and functional outcome, we commend its use in the immature population of long bone tumour cases.

There is very limited literature available on the use of prosthetic replacement in the treatment of primary and secondary tumours of the radius. In the past these were treated with vascularised and non-vascularised autografts which had associated donor site morbidity, problems of non union, graft or junctional fractures and delayed return to function. Our study is a mid to long term follow-up of implant survivorship and the functional outcome of metal prosthetic replacement used for primary and metastatic lesions of radius. We had 15 patients (8 males:7 females) with a mean age of 53 years. 8 patients underwent proximal radial replacement, 2 with mid-shaft radial replacement and 6 patients had distal radial replacements with wrist arthrodesis. The indications for replacement included metastatic lesions from renal cell carcinoma, primary giant cell tumours, ewings' sarcoma, chondroblastoma, radio-ulnar synostosis and benign fibrous histiocytoma. The average follow up was 5 years and 6 months (range 3 months - 18 years). Four patients died as a result of dissemination of renal cell carcinoma and two patients were lost to follow-up. There were no complications with the prosthesis or infection. Clinically and radiographically there was no loosening demonstrated at 18 years with secure fixation of implants. Two patients developed interossoeus nerve palsies which partially recovered. Functional outcomes of the elbow were assessed using the Mayo performance score with patients achieving a mean score of 85 postoperatively (range 65-95). All but one patient had full range of motion of the elbow. The patient with radio-ulnar synostosis had a 25 degree fixed flexion pot-operatively. Although the distal radial replacements had decreased range of movements of the wrist due to arthrodesis, they had excellent functional outcomes. Only one patient required revision surgery due to post-traumatic loosening of the implant. Our results of the use of endoprosthetic replacement of radius in the treatment of tumours are encouraging with regards to survivorship of the implant and functional outcome. This type of treatment results in an early return to daily routine activties, good functional outcome and patient satisfaction.

Purpose

The rate of arthroplasty or osteotomy in patients who had undergone autologous chondrocyte implantation (ACI) for osteochondral defects in the knee was determined. Furthermore, we investigated whether any radiographic evidence of osteoarthritis (OA) prior to ACI was associated with poorer outcome following surgery.

The aim of this study is to investigate whether Metal-on-Metal (MoM) implants result in more chromosome aberrations and increased blood metal ions post-operatively when compared to Metal-on-Polyethylene (MoP) implants. Metal-on-metal arthroplasties are being inserted in increasing numbers of younger patients due to the increased durability and reduced requirement for revision in these implants. Recent studies have raised many concerns over possible genotoxicity of MoM implants. This is a prospective study of patients who have undergone elective total hip replacement, they were selected and then randomised into two groups. Group A received a MoP implant and group B received a MoM implant. Patients are reviewed pre-operatively (control group), at 3 months, 6 months, 1 year and 2 years post-operatively. On each occasion blood tests are taken to quantify metal ion levels (chromium, cobalt, titanium, nickel and vanadium) using HR-ICPMS method and chromosome aberrations in T lymphocytes using 24 colour fluorescent in situ hybridisation (FISH). 53 patients have been recruited to date. 24 of whom had MoP prosthesis and 29 a MoM. 37 of these have had their one year follow-up with blood analysis and 14 have had 2 year follow up. Cobalt and chromium concentration increased during the first 6 months in both MoM and MoP groups, in the MoM group the chromium levels were twice that of MoP group and 12x that of the preoperative samples. Chromosome aberrations occurred in both groups. At 6 months both the MoM and MoP groups showed increase frequency of aneuploidy aberrations with further increases after one year. Structural damage in the form of translocations occurred in the MoM group after one year, but not in the MoP group, by two years there was a profound increase in translocations Preliminary results of this study show that the levels of chromium and cobalt are significantly higher in the MoM group compared to the MoP group. This corresponds to increases in chromosome aberrations in the groups with increases in structural chromosome damage after two years.

Polymethyl methacrylate spacers are commonly used during staged revision knee arthroplasty for infection. In cases with extensive bone loss and ligament instability, such spacers may not preserve limb length, joint stability and motion.

We report a retrospective case series of 19 consecutive patients using a custom-made cobalt chrome hinged spacer with antibiotic-loaded cement. The “SMILES spacer” was used at first-stage revision knee arthroplasty for chronic infection associated with a significant bone loss due to failed revision total knee replacement in 11 patients (58%), tumour endoprosthesis in four patients (21%), primary knee replacement in two patients (11%) and infected metalwork following fracture or osteotomy in a further two patients (11%). Mean follow-up was 38 months (range 24–70). In 12 (63%) patients, infection was eradicated, three patients (16%) had persistent infection and four (21%) developed further infection after initially successful second-stage surgery. Above knee amputation for persistent infection was performed in two patients.

In this particularly difficult to treat population, the SMILES spacer two-stage technique has demonstrated encouraging results and presents an attractive alternative to arthrodesis or amputation.

Introduction

We report the initial 2 and 3 year follow-up results of this randomised controlled trial of autologous chondrocyte implantation (ACI) using porcine-derived collagen membrane as a cover (ACI-C) versus matrix-carried autologous chondrocyte implantation (MACI) for the treatment of osteochondral defects of the knee.

Introduction

We discuss the use of the SMILES (Stanmore Modular Individualised Lower Extremity System) in salvage revision knee surgery and review the medium-long term results of 42 cases.

We performed a retrospective review of 98 patients with malignant tumours of the periacetabular region, treated by resection and endoprosthetic reconstruction between 1971 and 2005 at the Royal National Orthopaedic Hospital, Stanmore and The Royal Orthopaedic Hospital, Birmingham.

The mean age of the patients was 43.6 years (10 to 76). 53 patients (54%) were male. The age distribution demonstrated peaks in the 2nd and 6th decades. The mean follow up was 65 months (2 to 405. The overall 10-year survival rate was 56% (determined by the Kaplan-Meier method).

54 patients (58.1%) had one or more complications. Infection was the most common (30%) with the majority occurring in the first 2 years. Dislocation occurred in 19 (20%) of our patients all in the first year following surgery. All were recurrent with a mean of 2.9 (2 to 6) episodes. Operations performed before 1994 were associated with a dislocation rate of 40.5% and after 1996 the rate was only 3.9% (p < 0.001).

Function was assessed according the Toronto Extremity Salvage Sore (TESS). The overall TESS was 59.4. In patients that had a major complication the TESS was 37.1 but in the group that did not the TESS was 70.3 (p < 0.001).

Men experienced higher rates of death, infection and revision than women (p < 0.05). The local recurrence rate was 31% with high grade tumours associated with higher recurrence rates (p < 0.05). Tumour resection in the ilium is associated with higher rates of infection than tumours located in the periacetabular region alone (p < 0.05).

This method of reconstruction is still associated with high complication rates. Function is good if a major complication can be avoided. The lower dislocation rate more recently is probably the result of improved surgical technique and the use of larger femoral heads.