Introduction

Primary hip replacement in young active patients is on the increase. Due to the demands set by the patient, implants used in this patient group should have a proven long-term clinical and radiological outcome. We report our results in patients under the age of 50 using the C-Stem femoral component – a cemented triple tapered polished stem.

Introduction

Large acetabular bone defects caused by aseptic loosening are common. Reconstruction of large segmental defects can be challenging. Various implants and operative techniques have been developed to allow further acetabular revision in cases where bone stock is poor. Reconstitution of bone stock is desirable especially in younger patients. The aim of the study was to review the clinical and radiological results of hip revision with structural acetabular bone grafts using fresh frozen allograft and cemented components.

Introduction

Cross linked polyethylene (XLPE) has gained popularity as a bearing surface of choice for younger patients despite only medium term results being available for wear rates. Concern remains regarding the long-term stability and durability of these materials. In order to address these issues we present the longest radiological and clinical follow-up of XLPE.

Introduction

Severe osteolysis of the femur secondary to aseptic loosening in hip arthroplasty, remains a difficult revision scenario. Multiple techniques have been developed to aid the surgeon, including restoration of bone stock with impaction bone grafting or strut allografts, various distal fixation prostheses and mega-prostheses. Cemented femoral components, with integration of the cement into the cavitations, has largely fallen out of favour. We examined the long-term outcomes with this technique.

The C-Stem in its design as a triple tapered stem, is the logical development of the original Charnley flat-back polished stem. The concept, design and the surgical technique cater for a limited slip of the stem within the cement mantle transferring the load more proximally.

Five thousand two hundred and thirty three primary procedures using a C-stem have been carried out since 1993. We reviewed all 621 cases that had their total hip arthroplasty before 1998.

Sixty nine patients (70 hips) had died and 101 hips had not reached a ten-year clinical and radiological follow-up and had not been revised. Thirty-two hips had been revised before 10 years, none were revised for aseptic stem loosening and no stems. The indications for revision were Infection in 4, dislocation in 3, aseptic cup loosening in 24 and unexplained pain in 1.

The remaining 418 hips had a mean follow-up of 12 years (range 10–15 years). There were 216 women and 173 men, and 34 patients had bilateral LFAs. The patients' mean age at surgery was 53 years (range 16–83 years). Thirty four hips had been revised at the time of review. The reasons for revision were infection in 5, dislocation in 2, aseptic cup loosening in 24 and 1 for neuralgia paraesthetica where the stem was well fixed. Two hips were revised for stem fracture.

There were no revisions for stem loosening but 2 stems were revised for fracture - both with a defective cement mantle proximally. The clinical results are very encouraging and they support the concept of the Charnley cemented low friction arthroplasty, but place a demand on the understanding of the technique and its execution at surgery.

Introduction: Leg length discrepancy in general and leg lengthening in particular has emerged as a topic of interest and a common cause for litigation

Theoretical considerations: Painful mobile hip functions in abduction. The load on the hip is reduced by pelvic tilt to the symptomatic side. For this to be possible the proximal lever - the head neck and the acetabulum - must be relatively intact.

Methods: A method to identify patients at risk for limb lengthening after total hip arthroplasty by establishing the aetiology of abduction deformity of the osteoar-thritic hip.

Clinically: by pelvic tilt to the symptomatic side apparent limb lengthening, restriction of adduction.

Radiologically: by a relatively well preserved geometry of the hip and infero-medial femoral “head –drop” osteophyte.

Results: In a group of 5000 patients presenting for primary Charnley low-frictional torque arthroplasty: 182 (3.64%) 80 males, 102 females, mean age 63 (20–80) were identified as being at risk for post-operative limb lengthening.

Aetiology – Primary: Unilateral 130, Bilateral 10.

– Secondary: Post-surgery 23, post-trauma 10, spinal 6, mixed 3.

122 (67%) had apparent limb lengthening – mean 3.2% and in 43 (24%) limb lengths were equal, 91% had a well preserved architecture and the proximal lever system.

Discussion: The tell tale signs in patients at risk for limb lengthening after total hip arthroplasty are: pelvic tilt to the symptomatic side with apparent limb lengthening, restricted adduction, history of backache, well preserved hip structure and normal contralateral hip.

Conclusion: Awareness of the pattern identifying patients at risk, detailed pre-operative assessment, avoidance of capsule excision and tight hip reduction are essential.

With an increasing number of primary total hip arthroplasties being carried out worldwide, and a lack or inadequate follow-up leading to delays in revision surgery, more complex problems including periprosthetic fracture have to be dealt with at revision surgery.

Unawareness, that clinical results do not reflect the mechanical state of the arthroplasty, together with strain shielding in the femur, progressive endosteal cavitation and stem migration may result in deterioration of the periprosthetic bone stock and femoral fracture.

Acute onset due to the fracture, severe symptoms and poor medical status of the patient usually demands immediate surgical intervention.

We have developed a modular cemented femoral component for revisions where deficiency of the proximal femur, or the femoral fracture, demands a variable extra-femoral portion of the stem. The shaft of the stem is 200mm or longer allowing the extra-medullary position to vary up to 15cm. It has a double polished taper

Between 1985 and 2007 the stem has been used in 79 revisions where there was a periprosthetic fracture. The mean age at surgery was 70 years (37–93) and the mean follow-up was 4 years (0–14 years 10 months). In 86% the primary surgery had been performed at another hospital. In 80% the fracture had united at one year. The main post-operative problem was dislocation in 10 cases between 7 days and 9 years after revision and was most common where the abductors were absent. 2 patients died in the post-operative period. Five hips have been re-revised, 3 for dislocation, 1 for Infection and 1 stem loosening.

Overall revision for periprosthetic fracture using this implant has given good results.

Although the results of this type of surgery are encouraging, this must not be considered as an alternative to regular follow-up and early intervention in cases where progressive loosening and deteriorating bone stock are likely to lead to a more demanding surgery.

Introduction: The triple tapered polished cemented C-stem has evolved from the study on long-term results of the Charnley design, when first fractures of the stem and then proximal strain shielding of the femur and stem loosening were identified as the continuation of the same process. The design utilises the common engineering principle of male (stem) and female (cement) tapers engaging under load, loading the proximal femur.

Methods and Results: The C-stem was tested extensively and introduced into clinical practice in December 1993. Up to the end of October 2007, 4558 have been implanted in primary operations.

None of the 4558 stems have been revised for aseptic loosening or fracture.

The patient’s mean age at surgery was 48 years (range 15–76), and 171 hips with a mean follow-up of 11 years (range 10–13.7) have now passed 10 years. There were 97 females and 64 males in this group with 10 patients having bilateral C-stems. The main underlying pathologies were Primary Osteoarthritis 30%, Developmental Dysplasia of the hip 27% and Avascular Necrosis of the hip 19%.

Clinical outcome graded according to d’aubigne and postel for pain, function and movement has improved from 3.1, 3.1 and 2.9 to 5.9, 5.7 and 5.6 respectively.

A good quality proximal femur had been maintained in 47.1% and improved in a further 29.9%.

Discussion: The results achieved with the C-Stem design and technique are encouraging and support the concept of loading the proximal femur, but place a demand on the understanding of the technique and its execution at surgery.

Introduction. Presentation of results by survivorship analysis method offers uniformity of terminology and comparability of results, an essential aspect of scientific communication. The Swedish National Total Hip Arthroplasty Register (SNTHAR) has set the standards with revision as the failure endpoint.

We set out to examine the survivorship after primary Charnley low-frictional torque arthroplasty (LFA) with revision as the end point, but documenting all the operative findings.

Methods & Results. Between November 1962 and June 2005, 22,066 primary operations in 17409 patients had been carried out at the author’s hospital by over 330 surgeons. By June 2006, 1001 (4.5%) hips have been revised.

Survivorship with revision as the end point was: infection 95%, dislocation 98%, fractured stem 88.6%, loose stem 72.5%, loose cup 53,7%.

Infection and dislocation are early problems. With improved cementing techniques stem loosening does not become a problem until 11 years after the primary. Loosening and wear of the ultra high molecular weight polyethylene cup is a significant long-term problem.

Discussion. Since revision is an event interrupting a process, its timing will influence the survivorship analysis pattern and indications and detailed operative findings will become important issues. Since clinical results do not reflect the mechanical state of the arthroplasty to await symptoms would invariably mean that revisions are likely to be carried out late and as such the complexity of complications are likely to increase. Furthermore, if information gathered is of a single “indication for revision”, and not of the operative findings at revision, the information would be of limited value.

Our conclusion is that regular follow-up after hip replacement is essential. The frequency, judged from the revision patterns, would suggest that every two years would not be unreasonable. Recording of all operative findings at revision is essential.

Introduction: Bone stock and cement-bone interface in revision total hip replacement (THR) for deep infection have never been investigated in the literature, while they are known to be important for aseptic loosening. The purpose of this study was to assess preoperative bone stock and immediate postoperative cement-bone interface as factors affecting infection control and mechanical outcome after revision THR for deep infection.

Methods: This study included 115 cases in which revision THR with antibiotic-loaded cement was operated for infected hip replacement by a single surgeon with minimal follow-up of five years (range 5–27 years). Preoperative bone stock was classified into four grades (Grade 0: No bone loss, Grade 1: Demarcation, Grade 2: Localized cavitation, Grade 3: Extensive bone loss). The immediate postoperative cement-bone interface was also graded into four categories (Grade A: White-out, obscure interface, Grade B: Clear line, no measurable gap, Grade C: Gap> 1mm, Grade D< 1mm). These two factors were analysed with regard to infection control and mechanical survival of implants after surgery.

Results: Bone stock did not have significant influence on infection control while it affected mechanical outcome. The cement-bone interface was an affecting factor for not only the mechanical survival of implants but also the cure of infection.

Discussion: There was a good chance of curing the infection even with extensive bone loss. Good cement fixation was an important factor with regard to infection control as well as the mechanical survival of implants. The results suggested that it might be important to shield the medullary space from the infected joint space with antibiotic-loaded cement.

Introduction: We describe the association between postoperative femoral stem radiological appearances and aseptic failure of THA (total hip arthroplasty).

Methods: A retrospective review of records and radiographs of all patients attending for follow-up between August 2002 and August 2003 who had a cemented Charnley femoral stem and either a cemented polyethylene acetabular cup inserted. Femoral stem aseptic loosening was defined either by findings at revision surgery, the definite radiographic loosening criteria of Harris or progressive endosteal cavitation across zones as described by Gruen. Well-fixed control THA’s were defined as those that demonstrated none of the radiographic features of aseptic loosening or ‘at risk’ signs as described by Wroblewski. Parameters measured were: Alignment, Barrack grade of cementation, cement mantle width of the cement mantle and the presence and width of any radiolucent lines

Results: 63 hips were entered into the aseptic failure group and 138 into the control group. The alignment of the femoral stem was not associated with failure (p=0.283). Thickness of the cement mantle was statistically associated with failure in Gruen zones 6 (p=0.040) and Gruen zone 7 (p=0.003). A significant association for the presence of radiolucent lines was found for Gruen zones 3 (p=0.0001) and 5 (p=0.0001). The grade of cementation as measured by the Barrack grade was strongly associated with failure for grades C (p=0.001) and D (p=0.001).

Discussion and conclusion: This study has demonstrated that easily applied radiological criteria can be used to identify ‘at risk’ Charnley THA’s from the immediate post-operative AP radiograph.

Introduction. Preoperative bone stock and cement-bone interface in revision total hip replacement (THR) for deep infection have never been investigated while they are both well known to be important for mechanical outcome after revision THR for aseptic loosening.

Purpose. The purpose of this study was to assess pre-operative bone stock and immediate postoperative cement-bone interface as factors affecting infection control after one stage revision THR for deep infection.

Material and methods. This study included 115 cases which satisfied following conditions; a) One stage revision THRs for deep infection were carried out by a single surgeon. b) Follow-up of more than five years was done. Preoperative bone stock was classified into four grades (Grade 0: No bone loss, Grade 1: Demarcation, Grade 2: Localized cavitation, Grade 3: Extensive bone loss). Immediate postoperative cement-bone interface was also graded into four categories (Grade A: White-out, obscure interface, Grade B: Clear line, no measurable gap, Grade C: Gap within 1mm, Grade D: Gap more than 1mm). These two factors were analyzed in view of infection control after surgery.

Results. Preoperative bone stock did not show significant influence on infection control. Immediate postoperative cement-bone interface was an affecting factor for cure of infection.

Conclusion. There was a good chance of cure of infection even in cases with significant bone loss. Good cement fixation appeared to be important in view of infection control. The results suggested the importance of shielding of medullary space with antibiotic-loaded cement from infected joint space in revision THR for infection.

A single dislocation after total hip arthroplasty may not be a problem, once it becomes recurrent it rapidly undermines patients’ confidence. With an increasing number of revisions the problem of dislocations is likely to increase. The study and development of methods of prevention and management must proceed in pace with revision surgery.

We have designed a new cup: the angle-bore cup – to simulate both the structure and the function of the natural acetabulum with freedom of flexion, adduction, internal rotation and stability in the opposite direction. In its manufacture the centre of the hemisphere of the plastic is approached at an acute, less than 90 degrees angle, to the face of the cup creating a chamfer anteriorly and a recess postero-superiorly. The cup is side specific and cannot be reversed.

The angle-core cup was used in conjunction with a 22.225mm diameter head of the Charnley design with the exposure by trochanteric osteotomy. One thousand and thirty nine revisions were carried out: 505 were males and 534 females, mean age 65 (22.2 – 93.3): 66% were referred from other units. The indications for revision were: loose and worn cup 740, loose stem 553, deep infection 212, dislocation 65, fractured stem 51, bent stem 3, unexplained pain 17. There were 30 post-operative dislocations 2.9%; 22 (2.1%) had to be revised for recurrent dislocation. Of the 65 cases where dislocation was the original indication for revision 7 (10.8%) had to have further revision for dislocation.

(In 2330 primary Charnley low frictional torque arthroplasty with 22.225 mm diameter head and the angle-bore cup, there were 17 dislocations (0.73%); seven having to have revision for dislocation – a revision rate of 0.3% with a mean follow-up of 6.2 years.)

Full exposure, preservation of soft tissues, correct placement of components ensures stability in primary total hip arthroplasty. The same principles apply to revisions where the first attempt produces best results.

Dislocation after revision of 2.9% and re-revision for dislocation of 2.1% has been achieved with the 22.225 mm head and angle-bore cup. Advantages of the low-frictional torque can be maintained and low rate of dislocation achieved, even in revision surgery, using a 22.225 mm diameter head and the angle-bore cup.

We describe the association between immediate postoperative radiological appearances and early aseptic failure of THA having compensated for the methodological flaws in previous similar studies. 63 hips were entered into the aseptic failure group and 138 into the control group. Alignment of the femoral stem was not associated with failure (p=0.283). Thickness of the cement mantle was associated with failure in Gruen zones 6 (p=0.040) and 7 (p=0.003). A significant association for the presence of radiolucent lines was found for Gruen zones 3 (p=0.0001) and 5 (p=0.0001). Grade of cementation was associated with failure for Barrack grades C (p=0.001) and D (p=0.001). This study has demonstrated that easily applied radiological criteria can be used to identify at risk THAs from the immediate post-operative AP radiograph.

Introduction and Aims: The aim of this study was to evaluate the efficacy of one stage revision THA for deep infection with a long-term follow-up.

Method: One stage revision THA for deep infection was carried out in 273 joints on 262 patients by the senior author between 1974 and 2000. All infected hip replacements were primarily treated with one stage revision THA, regardless of microorganisms at the authors’ unit unless bone stock in the hips was too poor for implant fixation. This study included 162 revisions in 154 patients for which a minimum follow-up of five years (range 5.1 to 27.6 years; average 12.3 years) had been done. Fifty-two cases (32.1 %) had had discharging sinus by the time of revision surgery for infection.

Results: One hundred and thirty eight (85.2 %) hips were free of infection at the time of the latest follow-up. Twenty cases (12.3 %) had reoperation for recurrent infection. Four hips (2.5%) maintained their implants with the evidence of infection. Twenty-two cases (13.6 %) showed radiological loosening. Thirteen cases (8.0 %) were revised again for reasons other than infection (12 for aseptic loosening and one for dislocation).

Conclusion: Deep infection is one of the most serious complications after total hip arthroplasty (THA). This study presented the longest follow-up, with a large number of cases in revision THA for deep infection. The results suggested that one stage revision was an effective treatment for deep infection of hip arthroplasty.

Introduction and Aims: The purpose of this study was to assess pre-operative bone stock and immediate postoperative cement-bone interface as factors affecting infection control and mechanical outcome after one stage revision THR for deep infection.

Method: This study included 115 cases which satisfied the following conditions: 1) One stage revision THR for deep infection was the primary intervention for infected hip replacement by a single surgeon (BMW) unless the bone stock was too poor for fixing implants; 2) follow-up of more than five years; 3) A complete series of radiographs was available for radiological study including pre-operative and immediate post-operative ones. Pre-operative bone stock was classified into four grades (Grade 0: No bone loss, Grade 1: Demarcation, Grade 2: Localised cavitation, Grade 3: Extensive bone loss). The immediate post-operative cement-bone interface was also graded into four categories (Grade A: White-out, obscure interface, Grade B: Clear line, no measurable gap, Grade C: Gap> 1mm, Grade D< 1mm). These two factors were analysed with regard to infection control and the mechanical survival of implants after surgery.

Results: Bone stock did not have significant influence on infection control, while it did affect mechanical outcome. The cement-bone interface was an affecting factor for not only the mechanical survival of implants but also the cure of infection.

Conclusion: There was a good chance of curing the infection even with extensive bone loss. Good cement fixation was an important factor with regard to infection control, as well as the mechanical survival of implants. The results suggested that it was important to shield the medullary space from the infected joint space with antibiotic-loaded cement in revision THR for deep infection.

We explored the association of post-operative pyrexia following hip arthroplasty and the development of deep infection Method: The postoperative temperature records of 80 patient’s following primary hip replacement were retrospectively analysed. Thirty-one patients had revision surgery at a mean time interval of 37.2 months (range 5–74 months) for confirmed deep prosthetic infection. The control group of patients were asymptomatic at a mean follow-up of 31.5 months. There were 28 patients with an uneventful clinical outcome following surgery and 21 patients who had developed a systemic infection during their stay in hospital. The maximum daily temperature of each patient was recorded. Results: The mean peak temperature of patients with deep prosthetic infection was significantly lower then patients with a systemic infection or a normal clinical recovery following surgery (p=0.01). The difference between the peak post-operative temperature and the preoperative temperature was also significantly lower in patients who subsequently required revision surgery for prosthetic infection (p=0.007). Conclusion: Patients with deep prosthetic infection have a lower pyrexia response then patients with either an uneventful clinical recovery or the development of a systemic infection following total hip replacement. Pyrexia is part of the acute phase response following surgery is mediated by cytokines including IL-1 and IL-6, which are also involved in activation of the patients cellular and humoral immune response. A low pyrexia response following surgery may therefore also be suggestive of reduced acute phase response to the potential wound contamination produced during surgery with a consequence of subsequent prosthetic infection.

Pyrexia in the post-operative setting has often been associated with a possible systemic or wound infection. We assessed whether there is any justification for our concern regarding post-operative pyrexia following hip arthroplasty and subsequent deep prosthetic infection.

We undertook an assessment of the clinical outcome of 97 sequential patients who underwent 103 primary hip arthroplasty for primary osteoarthritis replacements. Daily temperature and systemic complications in the post-operative period were recorded. Clinical outcome was measured using an Oxford hip questionnaire.

Patients had a mean follow-up of 5.2 years (range 3.5–7.2years)

We reviewed the postoperative temperature records of 80 patients who had undergone primary total hip replacement. Thirty-one patients had required revision surgery at a mean time interval of 37.2 months (range 5–74 months) for confirmed deep prosthetic infection. The remaining Forty-nine patients were asymptomatic at a mean follow-up of 31.5 months.

Study 1

Post-operative pyrexia of 38 degrees Celsius was present in 51% of patients undergoing primary hip replacement in the first post-operative week but in 21.1% no etiological cause could be identified. Clinical outcome measured by an Oxford hip questionnaire was not influenced by the post-operative temperature pattern.

Study 2

The mean peak temperature on the first post-operative day was significantly lower in patients with deep prosthetic infection then patients with a clinically normal outcome (p=0.01).

Post-operative pyrexia is clearly not uncommon following primary arthroplasty and its presence should not be regarded as detrimental. Pyrexia in the postoperative setting is a component of the acute phase response to trauma and study 2 demonstrates patients who develop a low-grade infection following arthroplasty may have a diminished febrile response to surgical trauma which may be an indirect representation of a diminished immune response to surgical trauma or infection

Deep infection is one of the most serious complications after total hip replacement (THR). The aim of this study is to evaluate the efficacy of one stage revision THR for deep infection with a long-term follow-up.

One stage revision THR for deep infection was carried out in 285 joints on 274 patients by a single surgeon (BMW) between 1974 and 2001. All infected hip replacements are primarily treated with one stage revision THR at the authors’ unit unless bone stock is extremely poor. This study included a review of 162 revisions in 154 for which a minimum follow-up of five years had been done. The mean duration of follow-up was 12.3 years.

Trochanteric osteotomy was done for extensive resection of infected tissue and removal of cement. Both cups and stems were revised with bone cement. Antibiotic-loaded cement was used in 152 cases (93.8%). Further antibiotics were commenced systemically for 6–12 weeks postoperatively.

Failure of infection control was defined as a) reoperation for recurrent infection or b) clinically persistent infection. Infection control. One hundred and thirty eight hips (85.2%) were free of infection at the time of the latest follow-up. 1) No sinus group (N=110): Success rate was 82.7 %. 2) Sinus group (N=52): Success rate was 90.4 %.

This study presents the longest follow-up with a large number of cases in revision THR for deep infection. At least, history of discharging sinus was not considered as a contraindication. The results suggested that one stage revision was an effective treatment for deep infection of hip replacement in the long term.

Ultra high molecular weight polyethylene (UHMWPE) was introduced into clinical practice by Charnley in November 1962 and has remained the standard material for the hip and other total joint arthroplasties.

Wear of the UHMWPE cup, although studied from the beginning, did not appear to be a clinical problem although Charnley suspected that this would be so in the long term.

A review of the outcome of the Charnley low-friction arthroplasty in patients under the age of 40 years at the time of the operation has shown that the incidence of cup migration was exponentially related to the depth of cup penetration. A prospective study using 22.225 mm alumina ceramic (Al 20 3 ) head articulating with cross linked polyethylene was set up with the initial penetration of 0.2 – 0.4 mm in about 2.5 years with no further penetration. The clinical results mirrored closely the experimental results obtained with the identical set of materials and design. The clinical results have now reached 14 year follow-up and the initial total penetration of 0.2 – 0.4mm has remained unchanged.

Review of long term results of the Charnley LFA has shown a mean penetration rate of 0.1 mm/year (0.02 – 0.6). With a mean penetration rate of 0.1 mm/year, the revision rate for cup wear and loosening in patients under the age of 50 at the time of the LFA, and with a follow-up to 32 years, is in the region of 10%. If the penetration rate remained at 0.02 mm/year or less then no cups have been revised for aseptic loosening. Ceramic / UHMWPE articulation is the next stage of evolution of the Charnley LFA. A prospective study using zirconia 22.225 mm head is approaching 7 year follow-up in over 1000 cases.