Purposes

To compare the acetabular component size relative to the patient's native femoral head size between conventional THA (CTHA) approach and robotic-guided THA (RGTHA) to infer which of these techniques preserves more acetabular bone.

Introduction

Accurate component placement in total hip arthroplasty (THA) improves post-operative stability and reduces wear and aseptic loosening. Methods for achieving accurate stem placement have not been as extensively studied as cup placement.

We present to you a match-controlled study assessing co-existing arthroscopic findings during hip arthroscopy in patients with an intraoperative diagnosis of a central acetabular osteophyte (CAO). We feel that this manuscript is both pertinent and timely.

Recent literature has described the entity of central acetabular impingement, in which an osteophyte of the cotyloid fossa impinges against the superomedial femoral head and fovea. The technique for central acetabular decompression has also been described to treat this entity. The primary purpose of this study was to report the prevalence of femoral head articular damage in a matched cohort of patients with and without central acetabular osteophyte (CAO) that was identified during hip arthroscopy. A secondary purpose was to identify the rates of co-existing intraarticular pathology in both patient groups.

Intraoperative data was collected prospectively on all patients undergoing hip arthroscopy at our institution between February 2008 to March 2015,. The inclusion criteria for this study were the presence of a CAO identified during hip arthroscopy for a labral tear and/or femoroacetabular impingement (FAI). Exclusion criteria were revision surgeries, Tönnis grade 1 and higher, and previous hip conditions such as Legg-Calves-Perthes disease, avascular necrosis, and prior surgical intervention. The matched cohort control group was selected based on gender, age within 5 years, body mass index (BMI), and workers' compensation claim, on a 1:3 ratio to patients who underwent hip arthroscopy for a labral tear and/or FAI and did not have a CAO.

The CAO group consisted of 126 patients, which were matched to 378 patients in the control group. The grades of femoral and acetabular chondral damage were significantly different between the two groups (p<0.01).

This study showed that patients with CAO had a significantly higher prevalence of femoral and acetabular chondral damage, size of articular defects on both surfaces and the prevalence of LT tears compared to matched controls.

We present a prospective two-year follow-up study of 1038 hip arthroscopies performed at a high volume tertiary referral centre for hip preservation. We feel that this manuscript is both pertinent and timely due to the advances in the field of hip preservation.

We used four validated patient-reported outcome (PRO) scores along with the visual analog scale (VAS) and patient satisfaction scores to assess preoperative and postoperative outcomes in all patients undergoing hip arthroscopy. We divided the entire cohort into patients undergoing primary and revision hip arthroscopies. We found a statistically significant improvement from preoperative to two-year postoperative PRO scores in the two subgroups. We also found a significant difference in the PRO scores at three months, one year, and two years postoperatively between the primary and revision subgroups. The revision subgroup had inferior VAS and patient satisfaction compared to the primary subgroup, however these results were not significant. The conversion to total hip arthroplasty/hip resurfacing (THA/HR) was 5.6% and 11.2% in the primary and revision subgroups, respectively. This resulted in a relative risk of 2.0 for conversion to THA/HR in the revision subgroup. We had a complication rate of 5.3 (only 0.5% of which were considered major) which was similar to that reported in the literature for hip arthroscopy.

The primary purpose was to perform a survival analysis in a large mixed cohort of patients undergoing hip arthroscopy at a high volume tertiary referral centre for hip preservation with minimum two-year follow-up. The secondary purpose was to compare clinical outcomes of primary versus revision hip arthroscopy.

From February 2008 to June 2012, data were prospectively collected on all patients undergoing primary or revision hip arthroscopy. Patients were assessed pre- and post-operatively with modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), and Hip Outcome Score-Sport Specific Subscales (HOS-SSS). Pain was estimated on the visual analog scale (VAS). Patient satisfaction was measured on a scale from 0 to 10.

There were a total of 1155 arthroscopies performed, including 1040 primary arthroscopies (926 patients) and 115 revision arthroscopies (106 patients). Of these, 931 primary arthroscopies (89.5%) in 824 patients (89.0%) and 107 revision arthroscopies (93.0%) in 97 patients (91.5%), were available for follow-up and included in our study. The mean change in patient reported outcome (PRO) scores at two-year follow-up in the primary subgroup was 17.4 for mHHS, 19.7 for HOS-ADL, 23.8 for HOS-SSS, 21.3 for NAHS, and −3.0 for VAS. The mean change in PRO scores at two-year follow-up in the revision subgroup was 13.4, 10.9, 16.1, 15.4, and −2.7, respectively. All scores improved significantly compared to pre-operatively (p<0.001). PRO scores were higher at all time points for the primary subgroup compared to the revision subgroup (p<0.05). Satisfaction was 7.7 and 7.2 for primary and revision subgroups, respectively. Of 931 primary arthroscopies, 52 (5.6%) underwent THA/HR. Of 107 revision arthroscopies, 12 (11.2%) underwent THA/HR. The relative risk of a THA/HR was 2.0 after revision procedures compared to primary procedures. The overall complication rate was 5.3%.

Hip arthroscopy showed significant improvement in all PRO, VAS, and satisfaction scores at two years postoperatively. Primary arthroscopy patients showed greater PRO scores and a trend towards greater VAS compared to the revision subgroup. The relative risk of a THA/HR was 2.0 after revision procedures compared to primary procedures.

Background

Preservation of acetabular bone during primary total hip arthroplasty (THA) is important, because proper stability of cementless acetabular cup during primary THA depends largely on the amount of bone stock left after acetabular reaming. Eccentric or excessive acetabular reaming can cause soft tissue impingement, loosening, altered center of rotation, bone-to-bone impingement, intraoperative periprosthetic fracture, and other complications. Furthermore, loss of bone stock during primary THA may adversely affect subsequent revision THA.

Background

Preservation of acetabular bone during primary total hip arthroplasty (THA) is important, because proper stability of cementless acetabular cup during primary THA depends largely on the amount of bone stock left after acetabular reaming. Eccentric or excessive acetabular reaming can cause soft tissue impingement, loosening, altered centre of rotation, bone-to-bone impingement, intra-operative periprosthetic fracture, and other complications. Furthermore, loss of bone stock during primary THA may adversely affect subsequent revision THA.

Background: The combination of imageless computer aided navigation and minimally invasive surgery for total knee arthroplasty (TKA) has not been reported. Computer Aided Surgery (CAS) of the knee has demonstrated more reproducible component alignment compared to standard instrumentation. Minimally Invasive Surgery (MIS) for total knee arthroplasty allows for quicker rehabilitation and less post-operative pain. However, MIS has been associated with a higher complication rate, including component malalignment, compared to a conventional operative approach. Both MIS and CAS have been demonstrated to have a learning curve.

Aims: This study presents the initial 30 procedures in which imageless CAS was combined with MIS for TKA by the senior author. Specifically, we examined the accuracy of coronal alignment and the learning curve associated with the combined technique.

Between 6 and 12 weeks full length weight bearing radiographs were taken when patients could achieve full extension. Coronal alignments of the tibial and femoral components were calculated relative to the mechanical axis. The goal for both femoral and tibial component alignment was within 30 of 900 to the mechanical axis. The results were verified by an independent observer. Analysis of sequential tourniquet times, complication rates and component alignment were used as measure of the learning curve for the technique.

Component position was acceptable for all implants. The mean coronal tibial alignment was 90.35 degrees (range 88 to 92 degrees) and the mean coronal femoral alignment 90.10 degrees (range 88 to 93 degrees) to the mechanical axis. Tourniquet time averaged 90 minutes (range 60 to 118 minutes). There was no significant reduction in tourniquet time with increasing familiarity with the technique. Our results demonstrate that CAS combined with MIS for TKA maintains the accuracy of component alignment despite the minimally invasive approach. These initial results demonstrate no significant learning curve associated with the technique.

Background: Both chemical and mechanical methods of prophylaxis have reduced the the incidence of thromboembolic complications following Total Knee Replacement (TKR). Only a few studies have shown that mobilisation on the first post operative day further reduces the incidence of thromboembolic phenomena.

Aims: We conducted a prospective study to verify not only if early mobilisation but also whether the distance mobilised on the first post-operative day after TKR reduced the incidence of thromboembolic complications.

Methodology: The incidence of deep venous thrombosis and pulmonary embolism were compared in 50 consecutive patients who underwent TKR from July 2006 following a change in the mobilisation protocol with 50 consecutive patients who underwent TKR before the protocol was instigated. The mobilisation protocol changed from strict bed rest the first post operative day to mobilisation on the first post operative day. Mobilisation was defined as sitting out of bed or walking for at least 15–30 minutes twice a day. The distance mobilised was accurately recorded by the physiotherapists. All patients underwent duplex scans of both lower limbs on the fourth post operative day.

Results: There was a Significant reduction in the incidence of thromboembolic complications in the mobilisation group (7 in total) compared to the control group (16 in total) (p=0.03). Furthermore in the mobilisation group the odds of developing a thromboemobloic complication was Significantly reduced the greater the distance the patient mobilised, (Chi squared linear trend=8.009, p =0.0047).

Early mobilisation in the first 24 hours post TKR is a cheap and effective way to reduce the incidence of post-operative DVT.