Introduction

Osteolysis causing proximal femoral deficiency is a major problem in revision hip arthroplasty. Various methods including impaction bone grafting and bone allografts have been used to address this issue. We have analysed bone reformation using extended trochanteric osteotomy and distally fixed proximal hydroxyapatite-coated modular revision hip system (Stryker Restoration System) in 100 consecutive revisions by a single surgeon.

Introduction: In a climate of tightening budgets and rising cost the pressure on those performing complex and expensive surgery is ever increasing.

Patients requiring revision hip surgery are a particular burden on such limited resources.

Hospital trusts are dependent upon adequate remuneration for such complex procedures, a process reliant on accurate coding.

Methods: We performed a retrospective audit of our coding for revision hip surgery. This highlighted significant shortfalls in the coding process. We implemented necessary changes prior to a further prospective audit.

Results: The primary procedure was correctly coded in all our cases throughout, creating a standard tariff (mean £6,897).

However certain procedures enable an additional tariff uplift of up to 70%. Yet these additional procedures (performed in 81% of our procedures) had not been coded; loosing these additional tariff uplifts of 70%.

We involved and educated our coding staff, creating a ‘tick box’ sticker to be placed on every revision hip operation-record and completed by the operating surgeon.

Our subsequent tariff uplifts for these procedures have been significant.

Discussion: Joint replacement surgery is being performed in an ever younger and more active population. Patients are increasingly likely to outlive their prosthesis and peri-prosthetic fracture rates are set to continue rising.

In the modern NHS, surgeons must have a good understanding of complex tariffs. Coding staff are a notoriously poorly paid and undervalued component of any Hospital Trust, and invariably lack the surgical experience to interpret complex procedures.

Trusts must take measures to ensure such large tariff uplifts are not missed for complex procedures.

We explain the tariff process and discuss how improvements can easily be achieved by individual trusts.

Introduction and Aims: We describe the survival at 10 years of 134 consecutive JRI Furlong H.A.-coated uncemented total hip replacements.

Method: The follow-up was a minimum of 10 years (10.5–12 years). Patients were assessed by clinical and radiological means. We used Merle d’Aubigné and Postel (MDP) clinical score.

Radiological assessments identified radio-lucent lines, spot welding, pedestal formation and migration in order to assess fixation and stability of the femoral stem according to Engh’s criteria. DeLee and Charnley zones were used to assess loosening of the ace tabular cup. Subsidence, migration and cup-angle were also measured. The criteria for failure was revision or impending revision due to either pain, septic or aseptic loosening.

Results: The mean results of the MDP score were 7.4 pre-operation, and 15.9 post-operation. None of the acetabular cups in this series were revised. No femoral stem was revised for loosening. Six patients were lost to follow-up. Of the 128 femoral stems reviewed, only one was revised for periprosthetic fracture following a fall.

The success of uncemented arthroplasty depends on the achievement and maintenance of implant stability. Despite the use of modern instrumentation to obtain an accurate implant fit during total knee replacement, small gaps often remain visible at the bone-prosthesis interface on high quality fluroscopically-assisted radiographs. Although the clinical significance of these gaps is unclear, their presence delays bony fixation of the implant.

In uncemented total hip arthroplasty, hydroxyapatite costing has been used to enhance early stability of the implant: bony apposition has been shown to occur rapidly even in the presence of a small gap between the implant and the bone. In addition, recent RSA (Radio-stereo-photogrammateric analysis) studies have shown reduced micromotion and enhanced implant stability with hydroxyapatite coating of both hip and knee prostheses.

The following study was designed to observe and investigate the phenomenon of ‘gap-healing’ around hydroxyapatite coated uncemented total knee prostheses.

Over a 15-month period a hydroxyapatite coated uncemented total knee prosthesis was implanted in 99 patients undergoing 108 primary knee arthroplasties. The patients were prospectively reviewed at regular intervals with an average follow up of 18 months and a minimum of 12 months. The implant-bone interface was evaluated by obtaining serial fluroscopically-assisted radiographs.

On the immediate postoperative radiographs, small gaps between the implant and bone were seen in most knee. These gaps were visible on average in 2.16 AKS (American Knee Society)zones per knee. Most of the gaps were seen in Femoral zones 2,3,5 and Tibial zones 1 & 4. The majority of the gaps were under 1mm depth. Gaps> 2mm were seen only in 6 patients. Healing of the gaps was first seen at 3 months postoperatively, the average number of zones involved per knee dropping to 1.54. There was good evidence of ‘gap healing’ occurring at all the bone-implant interface zones. At the end of the first postoperative year, only 0.8 zones per knee were involved.2mm gaps remained visible in 3 patients.

In animal experiments, hydroxyapatitie coated porous surfaces have shown an increased the rate of bone ingrowth for as many as 52 weeks after implantation. In our study, progressive bone ingrowth and gap-healing has been observed beyond this period, the average involved zones on 2 –year radiographs being 0.4 per knee.

During the study period, the American knee score improved from 39.52 preoperatively to 89.97 at 1 year postoperatively. No relation was found between the clinical scores and the presence or absence of gaps on follow-up radiographs.

This study demonstrates the phenomenon of ‘gap-healing’ following uncemented hydroxyapatitie coated primary total knee arthroplasty in an unselected group of patients. Gaps under 1 mm at the implant –bone interface heal readily. Healing of gaps> 2mm is less predictable.

Certain cases of patello-femoral maltracking can lead to articular surface wear. Though most can be treated non-operatively, where there is increasing wear surgical intervention may be necessary. Patellar tracking is difficult to assess and though several different types of maltracking or loading have been described, each case warrants precise assessment of the wear patterns. Without this knowledge a logical approach to realignment surgery is impossible.

60 consecutive cases (age range 18–50 years) presenting with anterior knee pain were arthroscoped over a 4 year period. These patients all had been selected with either patellar instability or surface wear indicated either clinically, a positive radiograph, bone scan or MRI.

All patients were arthroscoped through standard anterolateral and antero-medial portals and also a superolateral and occasionally a supero-medial approach. The areas of articular damage were mapped on diagrams and recorded photographically. Patella views were taken in flexion and extension, and on passively stretching the patella medially and laterally.

We found 6 distinct patterns of wear which appear to indicate 6 different maltracking abnormalities. The largest group, 46 patients, consisted of lateral trackers, with 21 patients demonstrating medial facet and lateral femoral condylar wear.

Assessment of the articular surface of the patello-femoral groove from inferior portals is highly misleading and superior portals are needed for proper assessment. Medial facet wear can occur in lateral instability or medial compression. Lateral maltracking at engagement or distally are the commonest patterns.