Hip stability after ligamentum teres resection during surgical dislocation for cam impingement.

PURPOSE: The purpose of this study was to investigate whether patients who have undergone surgical hip dislocation with excision of the ligamentum teres exhibited symptoms of a Type I ligamentum teres rupture. METHOD: A questionnaire was designed to enquire about specific symptoms attributed to Type I injuries (complete rupture) in the literature: gross instability, incomplete reduction, inability to bear weight and mechanical symptoms. 217 consecutive patients were surveyed and 161 patients (75%) returned 168 questionnaires (75%). Mean age was 34 and median follow-up was 51 months (35 to 97). RESULTS: All patients were able to fully weight bear after surgery while 77% experienced no groin pain and 61% experienced no pain on exercise. 35% of patients experienced popping and locking in their operated hip and 24% had subjective feeling of their hip giving way. CONCLUSION: Patients who have had surgical excision of the ligamentum teres during open osteochondroplasty for cam deformities do not exhibit symptoms of a Type I ligamentum teres rupture. Our results show that minor instability symptoms may be present but symptoms present more like to Type II (partial) injuries. We propose that Type II injuries be divided into Type IIa; partial tear and Type IIb; iatrogenic rupture.

Hip resurfacing arthroplasty in patients with varus deformity of the femoral neck-shaft angle.

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, but there were no femoral neck fractures, early failures or revisions. The '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 and 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. We have not yet experienced any femoral neck fractures, which we believe is in part due to the use of an uncemented femoral component and preservation of blood supply.

Non-union following bilateral simultaneos Ganz trochanteric osteotomy.

Between January 2003 and December 2004, 13 patients underwent bilateral resurfacing arthroplasty via a Ganz trochanteric osteotomy. This bilateral group was mobilised fully weight-bearing with crutches. During the same period 139 Ganz trochanteric osteotomies were performed for unilateral hip resurfacing. These patients were mobilised with crutches, weight-bearing up to 10 kg on the operated leg. Nine osteotomies (32%) in the bilateral group subsequently developed a symptomatic non-union requiring revision of fixation. This compares with 10 patients (7%) in the unilateral group. Applying the Fisher's exact test, the difference reached significance (P=0.0004). In two patients a second revision was required to achieve union. In one patient, revision of trochanteric fixation precipitated a deep infection. Protected weight-bearing following a Ganz trochanteric osteotomy is important to the success of the procedure. Simultaneous bilateral hip arthroplasty through a Ganz approach should be avoided. If it is undertaken, we recommend that patients should be non weight-bearing for 6 weeks following surgery. Non-union following a Ganz trochanteric osteotomy for arthroplasty carries a significant morbidity.

Femoral oxygenation during hip resurfacing through the trochanteric flip approach.

Femoral neck fracture is one of the most common complications of hip resurfacing and considered by some to be related to reduced blood flow as a consequence of the surgical approach. We measured oxygen concentration during hip resurfacing through the trochanteric flip approach (n = 15 patients) and compared this approach with previous data for the posterior and anterolateral approaches. With the trochanteric flip the average femoral oxygenation decreased during the procedure to approximately 50% of that at the start, however it recovered to starting level by the end of the procedure. Preservation of oxygenation with the trochanteric flip was similar to that observed with the anterolateral approach, but with less variation during the procedure. Both of these approaches were superior in terms of oxygenation preservation to the posterior approach which resulted in a dramatic reduction in oxygenation.