Aims

Reconstruction of the acetabulum after failed total hip arthroplasty (THA) can be a surgical challenge in the presence of severe bone loss. We report the long-term survival of a porous tantalum revision acetabular component, its radiological appearance and quality of life outcomes.

There is increasing global awareness of adverse reactions to metal debris and elevated serum metal ion concentrations following the use of second generation metal-on-metal total hip arthroplasties. The high incidence of these complications can be largely attributed to corrosion at the head-neck interface. Severe corrosion of the taper is identified most commonly in association with larger diameter femoral heads. However, there is emerging evidence of varying levels of corrosion observed in retrieved components with smaller diameter femoral heads. This same mechanism of galvanic and mechanically-assisted crevice corrosion has been observed in metal-on-polyethylene and ceramic components, suggesting an inherent biomechanical problem with current designs of the head-neck interface.

We provide a review of the fundamental questions and answers clinicians and researchers must understand regarding corrosion of the taper, and its relevance to current orthopaedic practice.

Cite this article: Bone Joint J 2016;98-B:579–84.

Revision total hip arthroplasty (THA) is challenging when there is severe loss of bone in the proximal femur. The purpose of this study was to evaluate the clinical and radiographic outcomes of revision THA in patients with severe proximal femoral bone loss treated with a fluted, tapered, modular femoral component. Between January 1998 and December 2004, 92 revision THAs were performed in 92 patients using a single fluted, tapered, modular femoral stem design. Pre-operative diagnoses included aseptic loosening, infection and peri-prosthetic fracture. Bone loss was categorised pre-operatively as Paprosky types III-IV, or Vancouver B3 in patients with a peri-prosthetic fracture. The mean clinical follow-up was 6.4 years (2 to 12). A total of 47 patients had peri-operative complications, 27 of whom required further surgery. However, most of these further operations involved retention of a well-fixed femoral stem, and 88/92 femoral components (97%) remained in situ. Of the four components requiring revision, three were revised for infection and were well fixed at the time of revision; only one (1%) was revised for aseptic loosening. The most common complications were post-operative instability (17 hips, 19%) and intra-operative femoral fracture during insertion of the stem (11 hips, 12%). Diaphyseal stress shielding was noted in 20 hips (22%). There were no fractures of the femoral component. At the final follow-up 78% of patients had minimal or no pain.

Revision THA in patients with extensive proximal femoral bone loss using the Link MP fluted, tapered, modular stem led to a high rate of osseointegration of the stem at mid-term follow-up.

Cite this article: Bone Joint J 2015; 97-B:312–17.

Aims

In order to prevent dislocation of the hip after total hip arthroplasty (THA), patients have to adhere to precautions in the early post-operative period. The hypothesis of this study was that a protocol with minimal precautions after primary THA using the posterolateral approach would not increase the short-term (less than three months) risk of dislocation.

A moderator and panel of five experts led an interactive session in discussing five challenging and interesting patient case presentations involving surgery of the hip. The hip pathologies reviewed included failed open reduction internal fixation of subcapital femoral neck fracture, bilateral hip disease, evaluation of pain after metal-on-metal hip arthroplasty, avascular necrosis, aseptic loosening secondary to osteolysis and polyethylene wear, and management of ceramic femoral head fracture.

Aims

The primary aim of this study was to analyse the position of the acetabular and femoral components in total hip arthroplasty undertaken using an anterior surgical approach.

Aims

This retrospective cohort study compared the results of vascularised and non-vascularised anterior sliding tibial grafts for the treatment of osteoarthritis (OA)of the ankle secondary to osteonecrosis of the talus.

We describe our technique and rationale using hybrid fixation for primary total hip arthroplasty (THA) at the Hospital for Special Surgery. Modern uncemented acetabular components have few screw holes, or no holes, polished inner surfaces, improved locking mechanisms, and maximised thickness and shell-liner conformity. Uncemented sockets can be combined with highly cross-linked polyethylene liners, which have demonstrated very low wear and osteolysis rates after ten to 15 years of implantation. The results of cement fixation with a smooth or polished surface finished stem have been excellent, virtually eliminating complications seen with cementless fixation like peri-operative femoral fractures and thigh pain. Although mid-term results of modern cementless stems are encouraging, the long-term data do not show reduced revision rates for cementless stems compared with cemented smooth stems. In this paper we review the conduct of a hybrid THA, with emphasis on pre-operative planning, surgical technique, hypotensive epidural anaesthesia, and intra-operative physiology.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):54–9.

Bactericidal levels of antibiotics are difficult to achieve in infected total joint arthroplasty when intravenous antibiotics or antibiotic-loaded cement spacers are used, but intra-articular (IA) delivery of antibiotics has been effective in several studies. This paper describes a protocol for IA delivery of antibiotics in infected knee arthroplasty, and summarises the results of a pharmacokinetic study and two clinical follow-up studies of especially difficult groups: methicillin-resistant Staphylococcus aureus and failed two-stage revision. In the pharmacokinetic study, the mean synovial vancomycin peak level was 9242 (3956 to 32 150; sd 7608 μg/mL) among the 11 patients studied. Serum trough level ranged from 4.2 to 25.2 μg/mL (mean, 12.3 μg/mL; average of 9.6% of the joint trough value), which exceeded minimal inhibitory concentration. The success rate exceeded 95% in the two clinical groups. IA delivery of antibiotics is shown to be safe and effective, and is now the first option for treatment of infected total joint arthroplasty in our institution.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):31–6.

Aims

There are many guidelines that help direct the management of patients with metal-on-metal (MOM) hip arthroplasties. We have undertaken a study to compare the management of patients with MOM hip arthroplasties in different countries.

The traditional techniques involving an oblique tunnel or triangular wedge resection to approach a central or mixed-type physeal bar are hindered by poor visualisation of the bar. This may be overcome by a complete transverse osteotomy at the metaphysis near the growth plate or a direct vertical approach to the bar. Ilizarov external fixation using small wires allows firm fixation of the short physis-bearing fragment, and can also correct an associated angular deformity and permit limb lengthening.

We accurately approached and successfully excised ten central- or mixed-type bars; six in the distal femur, two in the proximal tibia and two in the distal tibia, without damaging the uninvolved physis, and corrected the associated angular deformity and leg-length discrepancy. Callus formation was slightly delayed because of periosteal elevation and stretching during resection of the bar. The resultant resection of the bar was satisfactory in seven patients and fair in three as assessed using a by a modified Williamson–Staheli classification.

Cite this article: Bone Joint J 2015;97-B:1726–31.

Tibial nonunion represents a spectrum of conditions which are challenging to treat, and optimal management remains unclear despite its high rate of incidence. We present 44 consecutive patients with 46 stiff tibial nonunions, treated with hexapod external fixators and distraction to achieve union and gradual deformity correction. There were 31 men and 13 women with a mean age of 35 years (18 to 68) and a mean follow-up of 12 months (6 to 40). No tibial osteotomies or bone graft procedures were performed. Bony union was achieved after the initial surgery in 41 (89.1%) tibias. Four persistent nonunions united after repeat treatment with closed hexapod distraction, resulting in bony union in 45 (97.8%) patients. The mean time to union was 23 weeks (11 to 49). Leg-length was restored to within 1 cm of the contralateral side in all tibias. Mechanical alignment was restored to within 5° of normal in 42 (91.3%) tibias. Closed distraction of stiff tibial nonunions can predictably lead to union without further surgery or bone graft. In addition to generating the required distraction to achieve union, hexapod circular external fixators can accurately correct concurrent deformities and limb-length discrepancies.

Cite this article: Bone Joint J 2015;97-B:1417–22.

The use of robotics in arthroplasty surgery is expanding rapidly as improvements in the technology evolve. This article examines current evidence to justify the usage of robotics, as well as the future potential in this emerging field.

There is a North Atlantic divide, with cementless femoral stems being used more frequently in the USA and cemented stems being used more frequently in many countries in Europe. This is primarily because different cemented stems have been used on different sides of the Atlantic and the results of the cemented stems in the US have often been poor, whereas the results of the stems used in Europe have been good. In the National registers in Europe, cemented stems have tended to achieve better results than cementless.

Cite this article: Bone Joint J 2013;95-B, Supple A:51–2.

Pelvic obliquity is a common finding in adolescents with cerebral palsy, however, there is little agreement on its measurement or relationship with hip development at different gross motor function classification system (GMFCS) levels.

The purpose of this investigation was to study these issues in a large, population-based cohort of adolescents with cerebral palsy at transition into adult services.

The cohort were a subset of a three year birth cohort (n = 98, 65M: 33F, with a mean age of 18.8 years (14.8 to 23.63) at their last radiological review) with the common features of a migration percentage greater than 30% and a history of adductor release surgery.

Different radiological methods of measuring pelvic obliquity were investigated in 40 patients and the angle between the acetabular tear drops (ITDL) and the horizontal reference frame of the radiograph was found to be reliable, with good face validity. This was selected for further study in all 98 patients.

The median pelvic obliquity was 4° (interquartile range 2° to 8°). There was a strong correlation between hip morphology and the presence of pelvic obliquity (effect of ITDL on Sharpe’s angle in the higher hip; rho 7.20 (5% confidence interval 5.59 to 8.81, p < 0.001). This was particularly true in non-ambulant adolescents (GMFCS IV and V) with severe pelvic obliquity, but was also easily detectable and clinically relevant in ambulant adolescents with mild pelvic obliquity.

The identification of pelvic obliquity and its management deserves closer scrutiny in children and adolescents with cerebral palsy.

Cite this article: Bone Joint J 2015;97-B:1435–40.

Following the recall of modular neck hip stems in July 2012, research into femoral modularity will intensify over the next few years. This review aims to provide surgeons with an up-to-date summary of the clinically relevant evidence. The development of femoral modularity, and a classification system, is described. The theoretical rationale for modularity is summarised and the clinical outcomes are explored. The review also examines the clinically relevant problems reported following the use of femoral stems with a modular neck.

Joint replacement registries in the United Kingdom and Australia have provided data on the failure rates of modular devices but cannot identify the mechanism of failure. This information is needed to determine whether modular neck femoral stems will be used in the future, and how we should monitor patients who already have them implanted.

Cite this article: Bone Joint J 2013;95-B:1011–21.

Two-stage exchange remains the gold standard for treatment of peri-prosthetic joint infection after total hip replacement (THR). In the first stage, all components and associated cement if present are removed, an aggressive debridement is undertaken including a complete synovectomy, and an antibiotic-loaded cement spacer is put in place. Patients are then treated with six weeks of parenteral antibiotics, followed by an ‘antibiotic free period’ to help ensure the infection has been eradicated. If the clinical evaluation and serum inflammatory markers suggest the infection has resolved, then the second stage can be completed, which involves removal of the cement spacer, repeat debridement, and placement of a new THR.

Cite this article: Bone Joint J 2013;95-B, Supple A:84–7.

Eighteen hip fusions were converted to total hip replacements. A constrained acetabular liner was used in three hips. Mean follow up was five years (two to 15). Two (11%) hips failed, requiring revision surgery and two patients (11%) had injury to the peroneal nerve. Heterotopic ossification developed in seven (39%) hips, in one case resulting in joint ankylosis. No hips dislocated.

Conversion of hip fusion to hip replacement carries an increased risk of heterotopic ossification and neurological injury. We advise prophylaxis against heterotropic ossification. When there is concern about hip stability we suggest that the use of a constrained acetabular liner is considered. Despite the potential for complications, this procedure had a high success rate and was effective in restoring hip function.

Tribocorrosion at the head–neck taper interface – so-called ‘taperosis’ – may be a source of metal ions and particulate debris in metal-on-polyethylene total hip arthroplasty (THA).

We examined the effect of femoral head length on fretting and corrosion in retrieved head–neck tapers in vivo for a minimum of two years (mean 8.7 years; 2.6 to 15.9). A total of 56 femoral heads ranging from 28 mm to 3 mm to 28 mm + 8 mm, and 17 femoral stems featuring a single taper design were included in the study. Fretting and corrosion were scored in three horizontally oriented concentric zones of each taper by stereomicroscopy.

Head length was observed to affect fretting (p = 0.03), with 28 mm + 8 mm femoral heads showing greater total fretting scores than all other head lengths. The central zone of the femoral head bore taper was subject to increased fretting damage (p = 0.01), regardless of head length or stem offset. High-offset femoral stems were associated with greater total fretting of the bore taper (p = 0.04).

Increased fretting damage is seen with longer head lengths and high-offset femoral stems, and occurs within a central concentric zone of the femoral head bore taper. Further investigation is required to determine the effect of increased head size, and variations in head–neck taper design.

Cite this article: Bone Joint J 2015; 97-B:911–16.