Jonathan Miles

Bizarre parosteal osteochondromatous proliferation of bone: CLINICAL MANAGEMENT OF A SERIES OF 22 CASES

We describe 22 cases of bizarre parosteal osteochondromatous proliferation, or Noras lesion. These are surface-based osteocartilaginous lesions typically affecting the hands and feet. All patients were identified from the records of a regional bone tumour unit and were treated between 1985 and 2009. Nine lesions involved the metacarpals, seven the metatarsals, one originated from a sesamoid bone of the foot and five from long bones (radius, ulna, tibia, and femur in two). The mean age of the patients was 31.8 years (6 to 66), with 14 men and eight women. Diagnosis was based on the radiological and histological features. The initial surgical treatment was excision in 21 cases and amputation of a toe in one. The mean follow-up was for 32 months (12 to 162). Recurrence occurred in six patients (27.3%), with a mean time to recurrence of 49 months (10 to 120). Two of the eight patients with complete resection margins developed a recurrence (25.0%), compared with four of 14 with a marginal or incomplete resection (28.6%). Given the potential surgical morbidity inherent in resection, our data suggest that there may be a role for a relatively tissue-conserving approach to the excision of these lesions.

Outcomes of infected revision knee arthroplasty managed by two-stage revision in a tertiary referral centre.

BACKGROUND A two-stage revision remains the gold standard to eradicate deep infection in total knee arthroplasty. Higher failure rates are associated with a number of factors including poly-microbial infections, multiresistant organisms and previous operations. The aims are to investigate [1] the overall success rate of a two-stage revision for infections in TKA, [2] the outcome of repeat two-stage revisions in recurrent infections and [3] the factors affecting the outcomes of such cases. METHODS We present the outcomes of a consecutive, retrospective case series of 51 periprosthetic joint infections managed with a two-stage revision knee arthroplasty over a three year period. RESULTS Forty-six (90%) of 51 were referred from other hospitals. Infection was successfully eradicated in 24 (65%) of 37 patients undergoing an initial two-stage procedure. Following a failed two-stage revision, a repeat two-stage revision was performed in 19 patients eradicating infection in 8 (42%). A third two-stage was performed in five of these patients eradicating infection in three with an average follow-up of 43 months. Multidrug resistance was present in 69%, and 47% of the patients were infected with multiple organisms. All unsuccessful outcomes involved at least one multidrug-resistant organism compared to 43% in the successful cohort (P=0.0002). Serological markers prior to a second-stage procedure were not significantly different between successful and unsuccessful outcome groups. CONCLUSION Single or multiple two-stage revisions can eradicate infection despite previous failed attempts. In this series, failure is associated with multidrug resistance, previous failed attempts to eradicate infection and a less favourable host response.

A new approach to managing patients with problematic metal hip implants: the use of an Internet-enhanced multidisciplinary team meeting: AAOS exhibit selection.

BACKGROUND Over one million patients worldwide are estimated to have a metal-on-metal hip arthroplasty. To improve the management of these patients and reduce surgeon uncertainty regarding decision-making, we designed an Internet-enhanced multidisciplinary team (iMDT) working approach. METHODS From August 2012 to April 2014, the iMDT discussed 215 patients with 266 metal-on-metal hip arthroplasties. Of these, 236 primary arthroplasties (132 hip resurfacing and 104 total hip) were analyzed. The remaining thirty cases involved problematic revised hips and were therefore excluded. The possible recommendations of the iMDT were monitoring, further investigation, or surgery. The concordance between the recommendation and the actual management was used to assess the usefulness of this approach in reducing uncertainty in surgeon-level decision-making. RESULTS The median Oxford Hip Score was 35 (range, 4 to 48), and median cobalt and chromium levels in whole blood were 3.54 ppb (range, 0.18 to 161.46 ppb) and 3.17 ppb (range, 0.20 to 100.67 ppb), respectively. Magnetic resonance imaging revealed abductor muscle atrophy in ninety-two (39%) of the hips and a pseudotumor in eighty (34%). The iMDT recommended monitoring of 146 (61.9%) of the hips, further investigation of thirty (12.7%), and surgery in sixty (25.4%). The actual outcome was concordant with the recommendation in 211 (91.7%) of the hips. CONCLUSIONS Our iMDT approach to the metal-on-metal hip burden combines the tacit knowledge of an expert panel, regulatory guidance, and up-to-date evidence to improve decision-making among surgeons. The high level of concordance between the recommendation and the actual outcome, combined with the feasibility of the methods used, suggest that this method effectively reduces uncertainty among surgeons and may lead to improved patient outcomes.This article was updated on March 27, 2015, because of a previous error. In Table IV, the heading that had previously read “High risk” now reads “Low risk” and vice versa. An erratum has been published: J Bone Joint Surg Am. 2015;97(9):e42. Background: Over one million patients worldwide are estimated to have a metal-on-metal hip arthroplasty. To improve the management of these patients and reduce surgeon uncertainty regarding decision-making, we designed an Internet-enhanced multidisciplinary team (iMDT) working approach. Methods: From August 2012 to April 2014, the iMDT discussed 215 patients with 266 metal-on-metal hip arthroplasties. Of these, 236 primary arthroplasties (132 hip resurfacing and 104 total hip) were analyzed. The remaining thirty cases involved problematic revised hips and were therefore excluded. The possible recommendations of the iMDT were monitoring, further investigation, or surgery. The concordance between the recommendation and the actual management was used to assess the usefulness of this approach in reducing uncertainty in surgeon-level decision-making. Results: The median Oxford Hip Score was 35 (range, 4 to 48), and median cobalt and chromium levels in whole blood were 3.54 ppb (range, 0.18 to 161.46 ppb) and 3.17 ppb (range, 0.20 to 100.67 ppb), respectively. Magnetic resonance imaging revealed abductor muscle atrophy in ninety-two (39%) of the hips and a pseudotumor in eighty (34%). The iMDT recommended monitoring of 146 (61.9%) of the hips, further investigation of thirty (12.7%), and surgery in sixty (25.4%). The actual outcome was concordant with the recommendation in 211 (91.7%) of the hips. Conclusions: Our iMDT approach to the metal-on-metal hip burden combines the tacit knowledge of an expert panel, regulatory guidance, and up-to-date evidence to improve decision-making among surgeons. The high level of concordance between the recommendation and the actual outcome, combined with the feasibility of the methods used, suggest that this method effectively reduces uncertainty among surgeons and may lead to improved patient outcomes.

Evidence from Raman Spectroscopy of a Putative Link Between Inherent Bone Matrix Chemistry and Degenerative Joint Disease

Osteoarthritis (OA) is a common debilitating disease that results in degeneration of cartilage and bone in the synovial joints. Subtle changes in the molecular structure of the subchondral bone matrix occur and may be associated with cartilage changes. The aim of this study was to explore whether the abnormal molecular changes observed in the matrix of OA subchondral bone can be identified with Raman spectroscopy.

Primary and revision total hip arthroplasty in osteogenesis imperfecta.

Due to an increasing lifespan, patients with osteogenesis imperfecta have a high incidence of hip osteoarthritis. The presence of recurrent fractures and deformities make primary and particularly revision total hip arthroplasty challenging. We present a series of patients with osteogenesis imperfecta undergoing total hip arthroplasty at a tertiary referral centre with a median follow-up of 7.6 years (4 to 35 years). There were four primary total hip arthroplasties and eight revision total hip arthroplasties performed in four patients. Three femoral components were custom computer assisted design computer assisted manufactured. The survival rate of the primary total hip arthroplasty was 16% and there were ten complications: five intraoperative fractures, one case of septic loosening and four cases of aseptic loosening. Patients with pre-operative acetabular protrusio were significantly more likely to require revision surgery (p = 0.02). At latest follow-up, the median Oxford hip score was 41 (37 to 46). As the largest series of primary and revision total hip arthroplasty performed in patients with osteogenesis imperfecta, we report good medium to long-term outcomes. Pre-Operative planning and consideration of custom made prostheses have an important role in these complex cases.

Muscle atrophy and metal-on-metal hip implants A serial MRI study of 74 hips

Background and purpose — Muscle atrophy is seen in patients with metal-on-metal (MOM) hip implants, probably because of inflammatory destruction of the musculo-tendon junction. However, like pseudotumors, it is unclear when atrophy occurs and whether it progresses with time. Our objective was to determine whether muscle atrophy associated with MOM hip implants progresses with time. Patients and methods — We retrospectively reviewed 74 hips in 56 patients (32 of them women) using serial MRI. Median age was 59 (23–83) years. The median time post-implantation was 83 (35–142) months, and the median interval between scans was 11 months. Hip muscles were scored using the Pfirrmann system. The mean scores for muscle atrophy were compared between the first and second MRI scans. Blood cobalt and chromium concentrations were determined. Results — The median blood cobalt was 6.84 (0.24–90) ppb and median chromium level was 4.42 (0.20–45) ppb. The median Oxford hip score was 34 (5–48). The change in the gluteus minimus mean atrophy score between first and second MRI was 0.12 (p = 0.002). Mean change in the gluteus medius posterior portion (unaffected by surgical approach) was 0.08 (p = 0.01) and mean change in the inferior portion was 0.10 (p = 0.05). Mean pseudotumor grade increased by 0.18 (p = 0.02). Interpretation — Worsening muscle atrophy and worsening pseudotumor grade occur over a 1-year period in a substantial proportion of patients with MOM hip implants. Serial MRI helps to identify those patients who are at risk of developing worsening soft-tissue pathology. These patients should be considered for revision surgery before irreversible muscle destruction occurs.

Custom rotating-hinge primary total knee arthroplasty in patients with skeletal dysplasia

Patients with skeletal dysplasia are prone to developing advanced osteoarthritis of the knee requiring total knee replacement (TKR) at a younger age than the general population. TKR in this unique group of patients is a technically demanding procedure owing to the deformity, flexion contracture, generalised hypotonia and ligamentous laxity. We retrospectively reviewed the outcome of 11 TKRs performed in eight patients with skeletal dysplasia at our institution using the Stanmore Modular Individualised Lower Extremity System (SMILES) custom-made rotating-hinge TKR. There were three men and five women with mean age of 57 years (41 to 79). Patients were followed clinically and radiologically for a mean of seven years (3 to 11.5). The mean Knee Society clinical and function scores improved from 24 (14 to 36) and 20 (5 to 40) pre-operatively, respectively, to 68 (28 to 80) and 50 (22 to 74), respectively, at final follow-up. Four complications were recorded, including a patellar fracture following a fall, a tibial peri-prosthetic fracture, persistent anterior knee pain, and aseptic loosening of a femoral component requiring revision. Our results demonstrate that custom primary rotating-hinge TKR in patients with skeletal dysplasia is effective at relieving pain, with a satisfactory range of movement and improved function. It compensates for bony deformity and ligament deficiency and reduces the likelihood of corrective osteotomy. Patellofemoral joint complications are frequent and functional outcome is worse than with primary TKR in the general population.

Custom-Made Cement-Linked Mega Prostheses: A Salvage Solution For Complex Periprosthetic Femoral Fractures

Periprosthetic femoral fractures with long stem implants, poor bone stock and loosening pose a considerable surgical challenge. We describe a reconstruction technique using a custom-made mega-prosthesis, cement-linked to the femoral stem of a well-fixed existing implant. Clinical and radiological outcomes were assessed at our tertiary referral centre. There were 15 patients with a periprosthetic femoral fracture: 5 proximal and 10 distal femoral arthroplasties linked to existing femoral stems. The survival rate was 93.3% at a mean follow-up of 5.3 years (0.5-19.3) with 1 revision. We present a salvage technique with good intermediate-term outcomes for highly selected patients with complex periprosthetic femoral fractures, as another option to conventional fixation methods. Specifically, it allows immediate weight bearing and avoids some of the morbidity of total femoral arthroplasty or amputation.

Use of metal proximal radial endoprostheses for treatment of non-traumatic disorders: A CASE SERIES

We have reviewed five adult patients treated with endoprosthetic reconstruction of the proximal radius following resection of non-traumatic lesions. The patients had a mean age of 33.4 years (20 to 60) at the time of surgery and the mean follow-up was 7.6 years (0.8 to 16). Following surgery, all elbows were clinically stable and there was 100% survivorship of the prosthesis. Evaluation of function was assessed clinically and by the Mayo Elbow Performance Score, achieving a mean of 86% (70 to 100). Results at medium-term follow-up are encouraging with regards to elbow stability, implant survivorship and functional outcome.

The effect of femoral head size on functional outcome in primary total hip arthroplasty: a single-blinded randomised controlled trial

We conducted a prospective single-blinded randomised controlled trial to compare the functional and quality of life outcomes in two groups of patients between 60 and 80 years of age undergoing THR; the first receiving a small head (28–32 mm) metal on polyethylene (MoP) articulation, and the second receiving a large head (44–54 mm) metal on metal (MoM) articulation. We recruited 49 patients and randomised them into one of the two groups (22 MoP and 27 MoM). The results demonstrated no statistical difference in any of the assessed functional outcomes at any follow-up point (p>0.05). There were no dislocations or revisions in either group. Although it has been suggested that large head MoM articulations in THA offer superior stability and function, our results suggest that small head MoP articulations can achieve comparable ROM, function and quality of life at short-term follow-up.