The December 2012 Hip & Pelvis Roundup. 360 . looks at: swimming against the tide with resurfacing; hip impingement surgery; the relationship between obesity and co-morbidities and joint replacement infection; cemented hips; cross-linked polyethylene notching; whether cement is necessary in oncological arthroplasty; and how total hip replacement may result in weight gain

Aims

This study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH).

We have analysed from the Finnish Arthroplasty Register the long-term survivorship of the 12 most commonly-used cemented implants between 1980 and 2005 in patients aged 55 years or older with osteoarthritis. Only two designs of femoral component, the Exeter Universal and the Müller Straight femoral component had a survivorship of over 95% at ten years with revision for aseptic loosening as the endpoint. At 15 years of the femoral and acetabular component combinations, only the Exeter Universal/Exeter All-poly implant had a survival rate of over 90% with revision for aseptic loosening as the endpoint. In the subgroup of patients aged between 55 and 64 years, survivorship overall was less than 90% at ten years. The variation in the long-term rates of survival of different cemented hip implants was considerable in patients aged 55 years or older. In those aged between 55 and 64 years, none of the cemented prostheses studied yielded excellent long-term survival rates (≥ 90% at 15 years)

Interfacial defects between the cement mantle and a hip implant may arise from constrained shrinkage of the cement or from air introduced during insertion of the stem. Shrinkage-induced interfacial porosity consists of small pores randomly located around the stem, whereas introduced interfacial gaps are large, individual and less uniformly distributed areas of stem-cement separation. Using a validated CT-based technique, we investigated the extent, morphology and distribution of interfacial gaps for two types of stem, the Charnley-Kerboul and the Lubinus SPII, and for two techniques of implantation, line-to-line and undersized. The interfacial gaps were variable and involved a mean of 6.43% (. sd. 8.99) of the surface of the stem. Neither the type of implant nor the technique of implantation had a significant effect on the regions of the gaps, which occurred more often over the flat areas of the implant than along the corners of the stems, and were more common proximally than distally for Charnley-Kerboul stems cemented line-to-line. Interfacial defects could have a major effect on the stability and survival of the implant

Aims

We wanted to evaluate the effects of a bone anabolic agent (bone morphogenetic protein 2 (BMP-2)) on an anti-catabolic background (systemic or local zoledronate) on fixation of allografted revision implants.

Aims

Improvements in functional results and long-term survival are variable following conversion of hip fusion to total hip arthroplasty (THA) and complications are high. The aim of the study was to analyze the clinical and functional results in patients who underwent conversion of hip fusion to THA using a consistent technique and uncemented implants.

The treatment of bony defects of the tibia at the time of revision total knee replacement is controversial. The place of compacted morsellised bone graft is becoming established, particularly in contained defects. It has previously been shown that the initial stability of impaction-grafted trays in the contained defects is equivalent to that of an uncemented primary knee replacement. However, there is little biomechanical evidence on which to base a decision in the treatment of uncontained defects. We undertook a laboratory-based biomechanical study comparing three methods of graft containment in segmental medial tibial defects and compared them with the use of a modular metal augment to bypass the defect. Using resin models of the proximal tibia with medial defects representing either 46% or 65% of the medial cortical rim, repair of the defect was accomplished using mesh, cement or a novel bag technique, after which impaction bone grafting was used to fill the contained defects and a tibial component was cemented in place. As a control, a cemented tibial component with modular metal augments was used in identical defects. All specimens were submitted to cyclical mechanical loading, during which cyclical and permanent tray displacement were determined. The results showed satisfactory stability with all the techniques except the bone bag method. Using metal augments gave the highest initial stability, but obviously lacked any potential for bone restoration

Aims

The prevalence of ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) is rising in concert with life expectancy, putting more patients at risk for interprosthetic femur fractures (IPFFs). Our study aimed to assess treatment methodologies, implant survivorship, and IPFF clinical outcomes.

Aims

Infection complicating primary total knee arthroplasty (TKA) is a common reason for revision surgery, hospital readmission, patient morbidity, and mortality. Increasing incidence of methicillin-resistant Staphylococcus aureus (MRSA) is a particular concern. The use of vancomycin as prophylactic agent alone or in combination with cephalosporin has not demonstrated lower periprosthetic joint infection (PJI) rates, partly due to timing and dosing of intravenous (IV) vancomycin administration, which have proven important factors in effectiveness. This is a retrospective review of a consecutive series of primary TKAs examining incidence of PJI, adverse reactions, and complications using IV versus intraosseous (IO) vancomycin at 30-day, 90-day, and one-year follow-up.

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° 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

Aims

Proximal femoral endoprosthetic replacements (PFEPRs) are the most common reconstruction option for osseous defects following primary and metastatic tumour resection. This study aimed to compare the rate of implant failure between PFEPRs with monopolar and bipolar hemiarthroplasties and acetabular arthroplasties, and determine the optimum articulation for revision PFEPRs.

Aims

Metal allergy in knee arthroplasty patients is a controversial topic. We aimed to conduct a scoping review to clarify the management of metal allergy in primary and revision total knee arthroplasty (TKA).

Aims

Robotic-assisted total knee arthroplasty (RA-TKA) is theoretically more accurate for component positioning than TKA performed with mechanical instruments (M-TKA). Furthermore, the ability to incorporate soft-tissue laxity data into the plan prior to bone resection should reduce variability between the planned polyethylene thickness and the final implanted polyethylene. The purpose of this study was to compare accuracy to plan for component positioning and precision, as demonstrated by deviation from plan for polyethylene insert thickness in measured-resection RA-TKA versus M-TKA.

Objectives. The objective of this study was to compare the early migration characteristics and functional outcome of the Triathlon cemented knee prosthesis with its predecessor, the Duracon cemented knee prosthesis (both Stryker). Methods. A total 60 patients were prospectively randomised and tibial component migration was measured by radiostereometric analysis (RSA) at three months, one year and two years; clinical outcome was measured by the American Knee Society score and the Knee Osteoarthritis and Injury Outcome Score. Results. There were no statistically significant differences in rotation or translation around or along the three coordinal axes, or in the maximum total point motion (MTPM) during the two-year follow-up. Conclusions. The Triathlon cemented knee prosthesis has similar early stability and is likely to perform at least as well as the Duracon cemented knee prosthesis over the longer term

In a prospective study between August 2002 and August 2005, we studied the quantitative clinical and radiological outcome 36 months after percutaneous vertebroplasty for intractable type-II osteoporotic vertebral compression fractures which had been unresponsive to conservative treatment for at least eight weeks. We also examined the quality of life (QoL). The clinical follow-up involved the use of a pain intensity numerical rating scale (PI-NRS, 0 to 10), the Short-Form 36 (SF-36) QoL questionnaire and an anamnestic questionnaire before and at seven days (PI-NRS only), and one, three, 12 and 36 months post-operatively. A total of 30 consecutive patients received percutaneous vertebroplasty for 62 vertebral compression fractures with a mean time between fracture and treatment of 7.7 months (2.2 to 39). An immediate, significant and lasting reduction in the average and worst back pain was found, represented by a decrease of 3.1 and 2.7 points after seven days and 3.1 and 2.8 points after 36 months, respectively (p < 0.00). Comparison of the pre- and post-vertebroplasty scores on the various SF-36 domains showed an ultimate significant increase in six of eight domains and both summary scores. Asymptomatic leakage of cement was found in 47 of 58 (81%) of treated vertebrae. Two minor complications occurred, an asymptomatic pulmonary cement embolism and a cement spur along the needle track. Percutaneous vertebroplasty in the treatment of chronic vertebral compression fractures results in an immediate, significant and lasting reduction in back pain, and overall improvement in physical and mental health

Pathological fractures due to metastasis with destruction of the acetabulum and central dislocation of the hip present a difficult surgical challenge. We describe a series using a single technique in which a stable and long-lasting reconstruction was obtained using standard primary hip replacement implants augmented by strong, fully-threaded steel rods with cement and steel mesh, where required. Between 1997 and 2006, 19 patients with a mean age of 66 years (48 to 83) were treated using a modified Harrington technique. Acetabular destruction was graded as Harrington class II in six cases and class III in 13. Reconstruction was achieved using three 6.5 mm rods inserted through a separate incision in the iliac crest followed by augmentation with cement and a conventional cemented Charnley or Exeter primary hip replacement. There were no peri-operative deaths. At the final follow-up (mean 25 months (5 to 110)) one rod had fractured and one construct required revision. Of the 18 patients who did not require revision, 13 had died. The mean time to death was 16 months (5 to 55). The mean follow-up of the five survivors was 31 months (18 to 47). There were no cases of dislocation, deep infection or injury to a nerve, the blood vessels or the bladder

Aims

Many surgeons choose to perform total knee arthroplasty (TKA) surgery with the aid of a tourniquet. A tourniquet is a device that fits around the leg and restricts blood flow to the limb. There is a need to understand whether tourniquets are safe, and if they benefit, or harm, patients. The aim of this study was to determine the benefits and harms of tourniquet use in TKA surgery.

We reviewed nine patients at a mean period of 11 years (6 to 16) after curettage and cementing of a giant-cell tumour around the knee to determine if there were any long-term adverse effects on the cartilage. Plain radiography, MRI, delayed gadolinium-enhanced MRI of the cartilage and measurement of the serum level of cartilage oligomeric matrix protein were carried out. The functional outcome was evaluated using the Lysholm knee score. Each patient was physically active and had returned to their previous occupation. Most participated in recreational sports or exercise. The mean Lysholm knee score was 92 (83 to 100). Only one patient was found to have cartilage damage adjacent to the cement. This patient had a history of intra-articular fracture and local recurrence, leading to degenerative changes. Interpretation of the data obtained from delayed gadolinium-enhanced MRI of the cartilage was difficult, with variation in the T1 values which did not correlate with the clinical or radiological findings. We did not find it helpful in the early diagnosis of degeneration of cartilage. We also found no obvious correlation between the serum cartilage oligomeric matrix protein level and the radiological and MR findings, function, time after surgery and the age of the patient. In summary, we found no evidence that the long-term presence of cement close to the knee joint was associated with the development of degenerative osteoarthritis

Aims

Debridement, antibiotics, and implant retention (DAIR) remains one option for the treatment of acute periprosthetic joint infection (PJI) despite imperfect success rates. Intraosseous (IO) administration of vancomycin results in significantly increased local bone and tissue concentrations compared to systemic antibiotics alone. The purpose of this study was to evaluate if the addition of a single dose of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes.