Background

Disruption of the normal relationship between the proximal tibia and fibula is seen in a number of different conditions such as skeletal dysplasias and post-infective deformity, as well as the consequence of lengthening procedures. Radiographic indices for the tibio-fibular relationship at the ankle have been described, but no similar measures have been reported for the proximal articulation.

Patients with DDH are known to be at risk of early degenerative changes to their hips. To date, no consensus exists as to the most appropriate management of this group, with many surgical options being associated with specific complications such as dislocation and early wear. In addition, modern resurfacing methods are considered by many to be contra-indicated in patients with DDH due to the technical difficulty of the procedure.

This prospective study analyses a single surgeon series of known DDH hips that underwent metal on metal resurfacing from November 1999 to July 2004 inclusive.

There were 31 resurfacings carried out on 28 patients (11 males, 17 females). The mean age of the study group at the time of surgery was 43.9+/−9.1 years. No patient was lost to follow up. Pre-operatively, 23 hips were classified as Crowe I (n=9), II (n=5), III (n=5) and IV (n=4). Patients were followed up to a mean of 46.4+/−18.1 months. The mean Harris Hip scores were 54.9+/−9.3 pre-operatively and 98.1+/−4.9 post-operatively (p< 0.001, Student’s t-test). Using the UCLA activity profile, the mean scores were 3.2+/−1.0 pre-operatively and 6.4+/−1.8 post-operatively (p< 0.001, Student’s t-test).

Although the management of young patients with early degenerative changes secondary to DDH remains controversial, the results of this study suggest that not only is resurfacing technically possible even in advanced cases, it also offers excellent functional outcomes and should be considered in appropriate cases.

Heterotopic ossification (HO) is a common complication following total hip replacement with a number of papers reporting an incidence of greater than 40%. In an effort to reduce the degree of contamination of the abductor muscle bed with osteoprogenitor cells, we used a plastic protective shield during the preparation and reaming of the femoral head in the hope that this would result in a decreased incidence of HO.

One hundred and forty consecutive metal-on-metal resurfacing procedures (mean age 52.3 years) utilizing the Birmingham hip prosthesis were performed between March 1999 and May 2002. Pre-operative diagnosis included osteoarthritis (105), Dysplasia (19), AVN (8), Inflammatory arthropathy (8). In the first 70 cases wet swabs packed around the femoral head were used in an attempt to reduce bone contamination. For all subsequent cases, bone contamination was controlled by the use of the plastic shield. Patients were reviewed clinically and radiologically at a mean of 36.1 (range 24–62) months post operatively. Pre-operative and follow up radiographs were assessed for presence of HO according to the Brooker classification. Harris hip and UCLA activity scores were recorded pre- and post-operatively on all patients. Three patients were lost to follow up.

Eighteen patients (12.9%) were noted to have HO on follow up radiographs. Sixteen patients in the initial group when no shield was used developed HO (Brooker I [10], II [2] & III [1]). Only two patients developed HO (Brooker I) following introduction of the protective shield. This modification in surgical technique was statistically significant in decreasing incidence of HO. All patients with radiological abnormalities were asymptomatic. We propose that this protective shield should be used during resurfacing hip arthroplasty as prophylaxis against ectopic new bone formation.

Introduction: There is a general conception in the orthopaedic community that blood loss/transfusion rate in hip resurfacing procedures is greater than that conventional Total Hip Arthroplasty (THA). The theoretical basis is that uncemented procedures leave large bleeding bone surfaces and that resurfacing arthroplasty needs larger incisions, greater exposure and more extensive soft tissue releases. Although this theory has gained informal

Acceptance in orthopaedic practice, there is little evidence in the literature to support this.

Background The purpose of this study was to determine the actual blood loss and transfusion rate (including hidden blood loss) in a consecutive cohort of patients undergoing hip re-surfacing by a single surgeon using the Articular Surface Replacement (ASR – DePuy).

Materials and Methods: The cohort consisted of 58 patients who were followed prospectively. All patients underwent a standardized surgical procedure performed by one senior surgeon. Hypotensive anaesthesia was used in all cases and surgery was via a standard posterior approach. Drains were not routinely placed, but if used, were removed within 24 hours. Low Molecular Weight Heparin was given 24 hours post procedure until discharge. Surgical blood loss was calculated in a standard fashion (suction volume plus swab weight). Drain volume (if used) was added after removal at 24 hours. Unseen loss of blood in soft tissues, joint space, as well as loss due to haemolysis, is calculated by the modified formula of Kallos¹:

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[MABL=\ EBV\ x\ (\underline{Hct\ pt\ -\ Hct\ min})\] \end{document}

Hct pt, Where is

MABL = Maximum allowable blood loss

EBV =Estimated blood volume, 70 ml/kg

Hct pt= Pre operative haematocrit of patient

Hct min=Minimum allowable haematocrit

This was modified to

\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(ABL=\ EBV\ {\times}\ \frac{(Hct\ pre\ op\ {-}\ Hct\ post\ opD2)}{Hct\ pre\ op}\) \end{document} where is

ABL= Actual blood loss, Unseen loss = ABL – Visible loss (Loss in OT + Drain)

Results: 58 Patients undergoing ASR, the aeitology was Osteoarthritis in 50 Patients, Dysplasia in 3, Inflammatory Arthritis in 1 and in 1 patient the aetiology was arthrosis secondary to trauma. The average blood loss during the procedure was 221 mls. After 24 hours this had risen to 377 ml, Mean Unseen blood loss was 787.6 ml, Mean Total actual blood loss was 1385.6 ml. There was a mean drop in haemoglobin of 3.6 g/dl and mean drop of Hematocrit was 10.33%. Only 3 patients required blood transfusion.

Conclusion: The mean blood loss in this study was 598 ml and actual blood loss was 1385.60. This is considerably lower than expected for resurfacing arthroplasty and results in a low transfusion rate of only 5% patients undergoing the procedure. Meticulous haemostasis combined with hypotensive anaesthesia reduced the perioperative blood loss and transfusion rate

We undertook this study to determine whether the concerns regarding early complications following hip resurfacing were justified. One hundred and twenty-nine consecutive resurfacing procedures (118 patients, mean age 52.3 years) utilising the Birmingham hip prosthesis were reviewed at a mean of 36.1 (range 24–62) months. Pre-operative diagnosis included osteoarthritis (94), Dysplasia (19), AVN (8), Inflammatory arthropathy (8). Immediate post-operative x-rays were analysed for prosthesis placement and interface gaps. Follow up films were assessed for lucent lines, osteolysis, bone resorption and component migration. Harris hip and UCLA activity scores were recorded pre and post operatively on all patients. Three patients were lost to follow up. Five cases were revised. Three cases due to femoral neck fracture. One patient developed late infection and subsequently fractured. All four patients underwent successful revision to an uncemented stem. One patient required revision of the acetabular component due to migration following a fall three years postop. Five cases of osteolysis were seen (Acetabulum (3), Femur (2)). Four cases of bone resorption at the femoral neck were noted. Two patients developed significant heterotopic ossification (Brooker II & III). All patients with radiological abnormalities were asymptomatic. The mean Harris hip score pre-operatively was 56.4 increasing to 97.5 post-operatively. The mean UCLA activity score pre-operatively was 3.3 increasing to 7.4 post-operatively. Kaplan-Meier survivorship was 94.7% at 5 years. Surface replacement gives excellent clinical results and offers significant advantages over conventional hip replacement. Long-term results are awaited to fully evaluate the effects of resurfacing arthroplasty.