Citations

Abstract: We previously compared the 15-year survivorship of total knee arthroplasty (TKA) implants that were mechanically aligned (0° ± 3° relative to the mechanical axis) compared with those that were outside that range and considered outliers. The original publication included 398 TKAs (292 in the aligned group and 106 in the outlier group) performed from 1985 to 1990. At the time of follow-up in the previous study, 138 patients (155 TKAs) had died and 59 knees had been revised. Since that publication, 49 additional patients (87 knees) have died. At 20 years, 57 (19.5%) of the 292 knees in the mechanically aligned group had been revised compared with 16 (15.1%) of the 106 knees in the outlier group (p = 0.97). Postoperative alignment within 0° ± 3° of the mechanical axis did not provide a functional advantage at 1, 5, 10, 15, and/or 20 years postoperatively as demonstrated by the Knee Society scores being similar between the groups (p ≥ 0.2 at all intervals). At 20 years, we once again did not find that neutral mechanical alignment provided better implant survivorship than that found in the outlier group. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

AbstractYoung hip surgeons are often faced with the decision to either perform arthroscopic surgery or a periacetabular osteotomy (PAO) in patients with symptomatic mild hip dysplasia (MHD). There is, however, a paucity of data on the results of PAO in this group. The aim of this paper is to report the results of PAOs in patients with MHD and compare those to hips with more severe forms of hip dysplasia (SHD). This data can then be used to compare emerging data reporting the results of hip arthroscopy for MHD. From January, 1996 to May, 2009, 299 hips in 268 patients were identified that underwent PAO at one institution. After removing those with <2 years of follow-up, 182 hips were followed up. The average age of the cohort was 31 years, and 85% were female. Nineteen hips with lateral center edge (LCE) angle from 18 to 25° and a Tönnis angle (TA) between 10 and 15° were considered to have MHD. This group was compared with the rest of the cohort (SHD). The mean clinical follow-up for the MHD group was 121 months. There was no significant difference in demographic variables between the groups. There were no complications in the MHD cohort. Surgical correction resulted in significant improvements in all radiographic measurements consistent with hip dysplasia in both groups. The Harris Hip Score (HHS) improved significantly in both groups ([MHD: 52–92] [SHD: 66–89]). Two hips (10.5%) in the MHD group and 15 hips (9.2%) in the SHD group underwent future THA (p = 0.69). The survivorship free from THA was 100%, 100%, and 86% at 3, 5, and 10 years, respectively, in the MHD group. The corresponding rates for hips in the control group at 3, 5, and 10 years, respectively, were 99%, 95%, and 81%. PAO in patients with MHD provides predictable improvements in pain, function, and results that are durable and comparable to hips with SHD. This data should be used to compare the early and midterm results of arthroscopic surgery performed in mildly dysplastic hips.

Obesity is a risk factor for complications following many orthopaedic procedures. The purpose of this study was to investigate whether obesity was an independent risk factor increasing the rate of complications following periacetabular osteotomy (PAO) and to determine whether radiographic correction after PAO was affected by obesity.We retrospectively collected demographic, clinical and radiographic data on 280 patients (231 women; 82.5% and 49 men; 17.5%) who were followed for a mean of 48 months (12 to 60) after PAO. A total of 65 patients (23.2%) were obese (body mass index (BMI) > 30 kg/m2). Univariate and multivariate analysis demonstrated that BMI was an independent risk factor associated with the severity of the complications. The average probability of a patient developing a major complication was 22% (95% confidence interval (CI) 11.78 to 38.21) for an obese patient compared with 3% (95% CI 1.39 to 6.58) for a non-obese patient The odds of a patient developing a major complication were 11 times higher (95% CI 4.71 to 17.60, p < 0.0001) for an obese compared with a non-obese patient.Following PAO surgery, there was no difference in radiographic correction between obese and non-obese patients. PAO procedures in obese patients correct the deformity effectively but are associated with an increased rate of complications.Cite this article: Bone Joint J 2015;97-B:29–34.

We surveyed 343 young women with 420 total hip arthroplasties (THAs) regarding pregnancy and childbirth after THA. The mean age at surgery was 35 years (18 to 45). The mean length of follow-up after the initial arthroplasty was 16 years (6 to 27).Of these 343 women, 47 (13.7%) had a successful pregnancy after their primary THA. The first baby after a THA was delivered vaginally in 30 patients and by Caesarean section in 17. Of the 343 patients, 138 underwent a revision. For the entire series, the risk of revision at five years was 5%, at ten years 24%, and at 20 years 50%. After adjusting for age at surgical intervention, the risk of revision was not significantly associated with childbirth. Of the 47 patients who had a successful pregnancy, 28 (60%) noted an increase in pain in the hip during pregnancy and ten of these patients had persistent pain after their pregnancy. Seven patients complained of pain in the groin in the replaced hip after childbirth. At the time of this survey, five of these patients (70%) had had revision THA.Childbirth is not affected by the presence of a THA. Pregnancy after THA is not associated with decreased survival of the prosthesis. Pain in the hip is common during pregnancy in these patients. Pain in the groin which persists after delivery commonly leads to revision of the THA.

The anterior centre-edge (VCA) angle quantifies the anterior cover of the femoral head, and angles of less than 20° are considered abnormal. We have measured the VCA angles in hips without osteoarthritic changes. We took bilateral false-profile radiographs of nine female and 30 male cadavers without signs of osteoarthritis. The mean age at the time of death was 72 years (46 to 92). The mean VCA angle was 32.8° (17.7 to 53.6). The SD was 7.9°. Our findings suggest that the threshold of abnormality of the VCA angle may be slightly lower than previously thought. This information may be useful in counselling patients with asymptomatic acetabular dysplasia.

Purpose To determine the contribution of the ligamentum teres (LT) to hip stability in the presence of an intact capsule with special attention to the change in range of motion and femoral head translation. Methods Seven fresh‐frozen cadaveric pelvises were used. Following visual inspection of the LT at different hip positions, internal rotation angles were measured at 10° of extension and at 0° of flexion, while external rotation was measured at 60°, 90°, and 110° of flexion with different hip abduction angles using electromagnetic motion tracking sensor. Femoral head translations were measured simultaneously. The tests were repeated after resection of the LT. The capsule was left intact for all test conditions. The results were compared between intact and LT resected conditions when torque of 2 and 4 Nm was applied. Results Compared with the intact hip, the LT resected hip showed no significant difference when 2 Nm torque was applied in all scenarios. With 4 Nm torque application, significant increase in external rotation was found at 60° and at 90° of flexion (1.7° ± 0.8° and 2.1° ± 1.0°, respectively). Significant difference was also noted at 60°, 90°, and 110° of flexion when the hip was in the adducted position while at 90° in the abducted hip. However, LT resection did not show significant change in internal rotation. There was no significant difference in the translation distance of the femoral head in the intact hip compared with the LT resected hip (0.77‐1.11 mm vs 0.79‐1.29 mm). Conclusions Our results indicate that within the physiologic range of motion, LT can minimally limit external rotation when the hip is in the flexed position but does not contribute to translation stability. Clinical Relevance In the hip with intact capsule, LT deficiency can result in a slight increase in range of motion, but its contribution to stability is questionable.

Background: Arthroplasty implants commonly contain elemental metal that may undergo wear-related release. Recently, cases of hip implant-associated myocardial injury have been reported. However, we are not aware of any previous study that has systematically measured myocardial metal levels or examined the relationship with total hip arthroplasty (THA). Methods: Archives of our institution were queried for autopsies of individuals who had undergone THA between 1990 and 2013. Myocardial tissue samples were analyzed for cobalt (Co) and chromium (Cr) levels with inductively coupled plasma mass spectroscopy. Seventy-five Co/Cr-on-polyethylene THA cases were included (mean age at time of death = 77.4 years; 49% women) as were 73 non-arthroplasty controls matched for age, sex, and history of hypertension and diabetes mellitus. Results: Significantly higher median myocardial concentrations of Co were observed in individuals with THA compared with controls (0.12 versus 0.06 μg/g, p < 0.0001). The median Co concentration was 69% higher in patients who had undergone THA revision (0.169 μg/g) than in those who underwent primary THA (0.100 μg/g; p = 0.004). In general, higher Co levels were observed in those with multiple replaced joints, although this finding only trended toward significance. Cardiomegaly, interstitial fibrosis, and decreased ejection fraction were observed more frequently in the postmortem samples of patients with implants than in those of controls (p = 0.0002, 0.044, and 0.0039, respectively). Conclusions: We believe this to be the first study to quantify metal levels in cardiac tissue in patients with and without joint replacement. The elevated Co levels, in concert with cardiomegaly and increased interstitial fibrosis found during autopsy, in the arthroplasty cohort are novel, important findings. Although Co levels were significantly elevated above those in controls, the majority were below those seen in clinical case reports of death from Co cardiotoxicity associated with metal-on-metal prostheses. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: The success of hip surgery in treating acetabular retroversion depends on the severity of the structural deformity and on selecting the correct patient for open or arthroscopic procedures. Purpose: To compare a group of patients with retroverted hips treated successfully with hip arthroscopy with a group of patients with retroverted hips that failed arthroscopic surgery, with special emphasis on (1) patient characteristics, (2) perioperative radiographic parameters, (3) intraoperative findings and concomitant procedures, and (4) patient sex. Study Design: Case-control study; Level of evidence, 3. Methods: We retrospectively reviewed the charts of 47 adult patients (47 hips) with acetabular retroversion who had undergone hip arthroscopy. Retroversion was based on the presence of an ischial spine sign in addition to either a crossover or posterior wall sign on a well-positioned anteroposterior pelvic radiograph. A total of 24 hips (50%) (16 females, 8 males; mean patient age, 31 years) had failed arthroscopy, defined as modified Harris Hip Score (mHHS) <80 or need for subsequent procedure. Twenty-three hips (8 females, 15 males; mean patient age, 29 years) were considered successful, defined as having no subsequent procedures and an mHHS >80 at the time of most recent follow-up. Perioperative variables, radiographic characteristics, and intraoperative findings were compared between the groups, in addition to a subgroup analysis based on sex. Results: The mean follow-up for successful hips was 30 months (SD, 11 months), with a mean mHHS of 95. In the failure group, 6 patients required subsequent procedures (4 anteverting periacetabular osteotomies and 2 total hip arthroplasties). The mean overall time to failure was 21 months, and the mean time to a second procedure was 24 months (total hip arthroplasty, 29.5 months; periacetabular osteotomy, 21.2 months); 18 hips failed on the basis of a low mHHS (mean, 65; range, 27-79) at last follow-up. Factors significantly different between the success and failure groups included patient sex, with males being more likely than females to have a successful outcome ( P < .02), as well as undergoing femoral osteoplasty ( P < .02). Intraoperative variables that were associated with worse outcome included isolated labral debridement ( P < .002). In a subgroup analysis, males were more likely than their female counterparts to have a successful outcome with both isolated cam and combined cam-pincer resection ( P < .05). Level of crossover correction on postoperative radiographs had no correlation with outcome. Conclusion: Acetabular retroversion remains a challenging pathoanatomy to treat arthroscopically. If hip arthroscopy is to be considered in select cases, we recommend labral preservation when possible. Male patients with correction of cam deformities did well, while females with significant retroversion appeared to be at greater risk for failure of arthroscopic treatment.