Hip resurfacing arthroplasty (HRA) in patients with a varus deformity of the femoral neck-shaft angle (NSA) is associated with poorer outcomes. Our experience has not reflected this. We examined the Oxford Hip Scores (OHS), Harris Hip Scores (HHS) and outcomes of patients with varus hips against a normal cohort to ascertain any significant difference.

We identified 179 patients. Measurement of the femoral neck-shaft angle was undertaken from antero-posterior radiographs pre-operatively. The mean NSA was 128.5 degrees (SD 6.3). Patients with a NSA of less than 122.2 were deemed varus and those above 134.8 valgus. These parameters were consistent with published anatomical studies.

The varus cohort consisted of 23 patients, mean NSA 118.7 (range 113.6-121.5), mean follow-up 49 months (range 13-74). Mean OHS and HHS were 16 and 93.5 respectively. Complications included 2 cases of trochanteric non-union; no femoral neck fractures, early failures or revisions. Normal cohort consisted of 125 patients, mean NSA 128 degrees, mean follow-up 41 months (range 6-76). The OHS and HSS were 18.8, 88.9 respectively. Complications included 5 trochanteric non-unions and 1 revision due to an acetabular fracture following a fall. Statistical analysis demonstrated no statistical difference between the cohorts OHS (p=0.583) or HHS (p=0.139).

Our experience in patients with a varus femoral neck has been positive. Our analysis has demonstrated no statistical difference in hip scores between the cohorts. We have not yet experienced any femoral neck fractures, which we believe is due to the use of the Ganz trochanteric flip and preservation of blood supply.

Choice of implant for patients aged sixty-five years or younger requiring hip arthroplasty is a topic of current debate, those in favor of resurfacing maintain it offers a greater range of motion and activity. We examined the Oxford Hip Score's (OHS) and Duke Activity Status Index (DASI) of patients undergoing either total hip replacement (THR) using an Elite Plus Stem, or hip resurfacing using a Birmingham Hip Resurfacing (BHR).

The THR cohort comprised 34 implants (4 bilateral), 17 men, 17 women, mean age 56.08 years. The resurfacing cohort comprised 27 implants (3 bilateral), 18 men, 9 women, mean age 50.51 years. The mean difference calculated between pre- and post-operative OHS was 22.08 and 25.33 for the THR and resurfacing cohorts respectively. The mean Duke score was 42.3 and 53 for the cohorts respectively.

Using the pre-operative and post-operative change in Oxford Hip Scores, no statistically significant difference was found between the THR and resurfacing cohorts (p = 0.2891). There was a statistically difference found between the THR and resurfacing cohorts with regards to activity using post-operative Duke scores, (p = 0.0047).

This study has emphasized the use of the DASI, a pure activity score, in hip research. In terms of reducing pain, both prostheses appear equally effective. With regards to activity, as evidenced by utilizing a pure activity score, the resurfacing cohort faired better. Our study suggests at one year post-op, young patients with a resurfacing have a greater activity level than those with a THR.

Hip resurfacing arthroplasty (HRA) in patients with a varus deformity of the femoral neck-shaft angle (NSA) has been cited in the literature as contributory factor towards a poorer outcome. Our experience has not reflected this. We examined the outcomes of patients with varus hips against a normal cohort.

Measurement of the femoral neck-shaft angle was undertaken from standard antero-posterior radiographs pre-operatively. The mean NSA was 128.5 degrees (SD 6.3). Patients less than 122.2 were deemed varus and those above 134.8 valgus. These parameters were consistent with the published literature.

The varus cohort consisted of 23 patients, mean NSA 118.7 (range 113.6-121.5), mean follow-up 49 months (range 13-74), mean OHS & HHS, 16 & 93.5 respectively. Complications included 2 cases of trochanteric non-union; no femoral neck fractures or revisions. The normal cohort consisted of 125 patients, mean NSA 128 degrees, mean follow-up 41 months (range 6-76), mean OHS & HSS, 18.8 & 88.9 respectively. Complications included 5 cases of trochanteric non-union and 1 revision. Statistical analysis demonstrated no difference between the cohorts OHS (p=0.583) or HHS (p=0.139).

Our experience in patients with a varus femoral neck has been positive. Our analysis has demonstrated no difference in outcomes between the cohorts.

The time at which patients should drive following total hip replacement (THR) is dependant upon recovery and the advice they are given. The Driver Vehicle and Licensing Agency (DVLA) in the United Kingdom does not publish recommendations following THR and insurance companies usually rely on medical instruction. Few studies have been performed previously and have reached different conclusions.

Brake reaction times for patients undergoing primary THR were measured pre-operatively and at four, six and eight weeks after surgery using a vehicle driving simulator at a dedicated testing centre. Patients were prospectively recruited. Ethical approval was granted. Participants included eleven males and nine females, mean age 69 years. Side of surgery, frequency of driving and type of car (automatic or manual) were documented. Patients with postoperative complications were excluded. No adverse events occurred during the study.

Statistical analysis using Friedman's test demonstrated a statistically significant difference (P=0.015) in reaction times across the four time periods. Wilcoxon test demonstrated a highly significant difference between initial and six week mean results (P=0.003), and between four and six week results (P=0.001). No significant difference was found between six and eight weeks.

Our data suggests reaction times improve until week six and significantly between week four to six. Patients making an uncomplicated recovery following primary THR may be considered safe to return to driving from week six onwards. We recommend this is clearly documented in the medical notes, and patients should check with their insurance company prior to recommencement.

The role of magnetic resonance arthrography (MRA) in the evaluation of patients with femeroacetabular impingement (FAI) to assess femoral head-neck junction asphericity and labral pathology is well established. However, in our experience the presence of acetabular cysts on MRA, which may signify underlying full thickness articular cartilage delamination and progression towards arthropathy, is also an important feature.

We retrospectively reviewed 142 hips (mean age 32 years, 47 men, 95 women), correlating the findings on MRA with those found at the time of open surgical hip debridement to ascertain the prevalence of acetabular cysts and the association with underlying acetabular changes. Fifteen MRA's demonstrated features consistent with underlying acetabular cystic change. At the time of surgery, this was confirmed in eleven cases that demonstrated a full thickness articular chondral flap (carpet lesion) and an underlying acetabular cyst. The sensitivity, specificity, positive predictive value and negative predictive value of MRA in relation to acetabular cysts was 55%, 96.7%, 73.3% and 92.9% respectively.

We believe acetabular cysts on MRA to be a significant finding. Such patients are likely to have an associated full thickness chondral lesion and features of early degenerative change, influencing outcome and prognosis. Our clinical practise has changed to reflect this finding. For those patients with cysts on MRA, we are less likely to offer open debridement and favour arthroscopic intervention followed by arthroplasty when symptoms dictate. We believe hip preservation surgeons should be aware of the significance of acetabular cysts and be prepared to adjust treatment options accordingly.