The direct anterior approach (DAA) is a popular minimally invasive approach for total hip arthroplasty (THA). It usually involves ligation of the lateral femoral circumflex artery's ascending branch (a-LFCA), which contributes to the perfusion of the tensor fasciae latae (TFL) muscle. Periarticular muscle status and clinical outcome were assessed after DAA-THA after a-LFCA preservation versus ligation.

We evaluated surgical records of 161 patients undergoing DAA-THA with tentative preservation of the a-LFCA by the senior author between May and November 2021. Among 92 eligible patients, 33 (35 hips) featured successful preservation, of which 20 (22 hips, 13 female) participated in the study. From 59 patients with ligated a-LFCA, 26 (27 hips, 15 female) were enrolled, constituting the control group. MRI and clinical examinations were performed at 17–26 months to analyze volume and fatty infiltration of the TFL, gluteus medius and gluteus minimus muscles relative to the contralateral non-THA hip (15 preserved, 18 ligated). Clinical and radiographic data was retrospectively extracted from patient files. Patient-reported outcomes (PROMs) were added from the THA registry.

There was a relative difference in TFL muscle volume of -6.27 cm³ (−9.89%, p=0.018) after a-LFCA preservation versus -8.6 cm³ (=11.62%, p=0.002) after ligation, without group differences (p>0.340). a-LFCA preservation showed lower relative TFL fatty infiltration (p=0.10). Gluteal muscle status was similar between sides and groups. Coxa valga morphology was more frequent in a-LFCA preservation (83%) than ligation (17%). Clinical outcomes showed high patient satisfaction in both groups, without difference in PROMs, but less anterolateral soft-tissue swelling after a-LFCA preservation (p<0.001).

Despite excellent clinical results in both groups, preservation of the a-LFCA was associated with less TFL fatty infiltration and soft tissue swelling. Provided there is no compromise of intraoperative access we recommend a-LFCA preservation for DAA-THA.

The Bernese periacetabular osteotomy (PAO) is not indicated for growing hips as it crosses the triradiate cartilage in its posterior branch, and experimental work has shown this can induce substantial deformations, similar to posttraumatic dysplasia, which is observed after pelvis crash injuries in childhood.

Upon examination, all injuries in the 19 cases of posttraumatic dysplasia described in literature plus 16 hips of our personal collection took place before the age of 6, which is striking as pelvic injuries in children increase with age.

Based on this observation, we started to extend the PAO indication to severe dysplasias in children with open growth plate, initially aged 9 years and older. Following the positive results, it was extended further, our youngest patient being 5 years old.

We retrospectively examined radiographic outcomes of 23 hips (20 patients), aged 10.6±1.8 years [range 5.0 – 13.2], operated by us in four centers. Pre- and 3-months postoperative, and the latest FUP radiograph at growth plate closure were measured. We evaluated the acetabular index (AI), lateral center-edge (LCE), ACM-value and compared them with reference values adjusted for age. The age at triradiate cartilage closure was compared with the non-operated side.

The follow-up time was 5.4±3.7 years [0.8 - 12.7]. In 5 hips, growth plate closure was delayed by a few months. All angles significantly normalized after PAO (LCE: 14±8° → 38±11°, AI: 20±8° → 7±4°, ACM: 53±5° → 48±4°), with >80% of them severe pathological pre-PAO, none afterwards. Acetabular molding was normal. Only few complications occurred; one had signs of coxarthosis, one sciatic nerve pain, one interfering osteosynthesis material that was removed, one had an additional valgus osteotomy, and all resolved.

Based on 20 cases with follow-up until complete triradiate cartilage closure, we believe to have sufficient information to extend the PAO indication to growing hips of 9 years and older.

Aims

The purpose of this study was to evaluate the mid-term outcomes of autologous matrix-induced chondrogenesis (AMIC) for the treatment of larger cartilage lesions and deformity correction in hips suffering from symptomatic femoroacetabular impingement (FAI).

Femoroacetabular impingement is a prearthritic deformity frequently associated with early chondral damage. Several techniques exist for restoring larger cartilage defects. While AMIC proved to be an effective treatment in knee and ankle, there are only short-term data available in hip. This study aimed to investigate the mid-term clinical outcome of patients with chondral lesions treated by AMIC and evaluate the quality of repair tissue via MRI.

This retrospective, single center study includes 18 patients undergoing surgical hip dislocation for FAI between 2013 and 2016. Inclusion criteria were: cam or pincer-type FAI, femoral or acetabular chondral lesions > 1 cm², (IRCS III-IV). Due to exclusion criteria and loss-to-follow-up 9 patients (10 hips) could be included. Patient reported outcome measures included Oxford Hip Score (OHS) & Core Outcome Measure Index (COMI)). MRIs were evaluated using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score.

None of the patients underwent revision surgery except screw removals from the greater trochanter. Followup data indicate a satisfactory to good hip function at 5 years: PROMS improved from pre- to postop at 5 years: OHS from 38.1 to 43.4, COMI from to 1.8 and UCLA from 4 to 8.1 respectively. MOCART score was 67.5 postoperatively. Subgrouping showed slightly better results for acetabular defects (Ø 69.4) compared femoral defects (Ø 60).

Based on the reported mid-term results, we consider AMIC as a valuable treatment option for larger chondral defects of the hip.

Aims

Avascular femoral head necrosis in the context of gymnastics is a rare but serious complication, appearing similar to Perthes’ disease but occurring later during adolescence. Based on 3D CT animations, we propose repetitive impact between the main supplying vessels on the posterolateral femoral neck and the posterior acetabular wall in hyperextension and external rotation as a possible cause of direct vascular damage, and subsequent femoral head necrosis in three adolescent female gymnasts we are reporting on.

Aims

It is not known whether preservation of the capsule of the hip positively affects patient-reported outcome measures (PROMs) in total hip arthroplasty using the direct anterior approach (DAA-THA). A recent randomized controlled trial found no clinically significant difference at one year postoperatively. This study aimed to determine whether preservation of the anterolateral capsule and anatomical closure improve the outcome and revision rate, when compared with resection of the anterolateral capsule, at two years postoperatively.

Until today it is unknown whether preservation of the joint capsule positively affects patient reported outcome (PROs) in DAA-THA. A recent RCT found no clinical difference at 1 year. Since 2015 we preserve the capsule suture it at the end. We here evaluate whether this change had any effect on PROs and revisions, 2 years post-operatively.

Two subsequent cohorts operated by the senior author were compared. The capsule was resected in the first cohort (January 2012 – December 2014) and preserved in the second cohort (July 2015 – December 2017). No other technical changes have been introduced between the two cohorts. Patient demographics, Charlson Comorbidity Index (CCI), and surgical data were collected from our clinical information system. 2-years PROs questionnaires (OHS, COMI Hip) were obtained. Data was analyzed with generalized multiple regression analysis.

430 and 450 patients were included in the resected and preserved cohorts, respectively. Demographics, CCI surgical time and length of stay were equal in both groups. Blood loss was less in the preserved cohort (p<.05). Four patients had a revision (1 vs 3, n.s.). Once corrected for demographics, capsule preservation had significant worse PROs: +0.24 COMI (p<.001) and −1.6 OHS points (p<.05), however, effects were much smaller than the minimal clinically important difference (0.95 and 5 respectively). The date of surgery (i.e. surgeon's age) was not a significant factor.

In this large retrospective study, we observed statistically significant, but probably clinically not relevant, worse PROs with capsule preservation. It might be speculated that the not resected hypertrophied capsule could have caused this difference.

Femoral head necrosis in the context of high impact gymnastics of young adolescents is rare but seems a more serious complication compared to a Perthes like necrosis.

Between 2017 and 2019, three young females aged from12 to 14 years were referred due incapacitating hip pain and severe collapsing femoral head necrosis. The indication of hip preserving surgery was based on the extent of the necrosis, presence of a vital lateral pillar and joint subluxation.

In one of our 3 cases total head involvement made THR necessary, which was performed elsewhere. In the remaining 2 cases, head reduction osteotomy plus periacetabular osteotomy led to a good and a fair result.

Repetitive impact between the main supplying vessels on the posterolateral femoral neck and the posterior acetabular wall in hyperextension/ external rotation could be the cause of severe femoral head necrosis in three adolescent female gymnasts we are reporting on. Supra-selective angiography or sonography may be helpful to improve indication. Targeted adaptation of training methods should be discussed. Due to the severe vascular insult, results have to be considered moderate.

To characterize the quality of flap tissues and the resident cells in order to provide a scientific rationale for reattaching flap tissues during surgery.

11 acetabular chondral flaps and 3 non-delaminated cartilage samples were resected during open hip surgeries and the anatomical orientation was marked. The viability was measured in 7 flaps with Live Dead staining and the distribution of the extracellular matrix components was investigated in 7 oriented flaps by histology. The chondrogenic potential of the residing cells (P2) was investigated via pellets assays (5 flaps). Their capacity to outgrow from flap particles was tested upon encapsulation in 4mm-diameter fibrin glue discs (6 flaps).

The viability in flaps was 49.4 ± 6.5 % compared to 70.6 ± 8.2 % in non-delaminated cartilage, (not significant). Histology showed a progression of fibrillation from the delaminated side towards the site of attachment. This degraded state correlated with the capacity of the cells to outgrow, with 60.6 ± 33 % of the gel area covered by migrating cells after 4 weeks in culture. However, the cells in flaps showed a decreased chondrogenic potential than chondrocytes from non-delaminated cartilage.

Our findings indicate that flaps contain viable cells that can outgrow from the tissue due to the degraded state of the matrix. The poor chondrogenic property of the cells suggests they are unlikely to produce enough matrix to provide a solid attachment of the delaminated tissue upon migration.

Aims

The classical longitudinal incision used for the direct anterior approach (DAA) to the hip does not follow the tension lines of the skin and can lead to impaired wound healing and poor cosmesis. The purpose of this retrospective study was to determine the satisfaction with the scar, and functional and radiographic outcomes comparing the classic longitudinal incision with a modified skin crease ‘bikini’ when the DAA is used for total hip arthroplasty (THA).

Severe femoral head deformities due to Perthes' disease are characterized by limitation of ROM, pain, and early degeneration, eventually becoming intolerable already in early adulthood. Morphological adaptation of the acetabulum is substantial and complex intra- and extraarticular impingement sometimes combined with instability are the underlying pathologies.

Improvement is difficult to achieve with classic femoral and acetabular osteotomies. Since 15 years we have executed a head size reduction. With an experience of more than 50 cases no AVN of the femoral head was recorded. In two hips fracture of the medial column of the neck has been successfully treated with subsequent screw fixation. The clinical mid-term results are characterized by substantial increase of hip motion and pain reduction.

Surgical goal is to obtain a smaller head, well contained in the acetabulum. It should become as spherical as possible and the gliding surface should be covered with best available cartilage. Together, it has to be accomplished under careful consideration of the blood supply to the femoral head. In the majority of cases acetabular reorientation is necessary to optimize joint stability.

Femoral head segment resections without guidance is difficult. Therefore, 3D-simulation for cut direction and segment size including the implementation of the resultant osteotomy configuration was developed using individually manufactured cutting jigs. First experience in five such cases have revealed good results. The forthcoming steps are the improvement of computer algorithm and automation. Goal is that with first cut decision the other cuts are automatically determined resulting in optimal head size and sphericity.

The classical longitudinal incision used for the direct anterior approach (DAA) does not follow the relaxation tension lines of the skin and can lead to impaired wound healing and poor scar cosmesis. The purpose of this study was to determine patient functional and radiographic outcomes of a modified skin crease “bikini” incision used for the DAA in THR.

964 patients (51% female; 59% longitudinal, 41% bikini) completed 2 to 4 years after surgery a follow-up questionnaire including the Oxford Hip Score (OHS), the University of North Carolina 4P scar scale (UNC4P), and two items for assessing aesthetic appearance and symptoms of numbness. Implant position, rates of radiographic heterotopic ossification and required revision were assessed.

UNC4P total (p<0.001) and OHS (p=0.013) scores were better in the bikini compared the longitudinal group. The proportion of aesthetically very satisfied patients was higher (p<0.001) in the bikini group. The proportion of patients reporting numbness in the scar was higher (p<0.001) in the longitudinal (14.5% versus 7.5%, respectively). Radiographic cup abduction angles, stem position and ectopic ossification rates did not differ between the groups. No differences in the revision rates of both groups being 2.1% in the longitudinal and 1.5% in the Bikini group. Although differences were not huge, Bikini incision resulted in better patient-related outcomes and satisfaction related to the scar. Our study showed that a short oblique “bikini” skin crease incision for the DAA can be performed safely without compromising implant positioning or increasing symptoms suggesting lateral femoral cutaneous nerve dysesthesia. As it is less extensile it should be used after having gained significant experience with the classic longitudinal incision.

Dedication to quality has a longstanding tradition within the Schulthess Clinic. Pioneering documentation Maurice E. Müller initiated an International Documentation & Evaluation System (IDES) in the era of hip replacement becoming an increasingly wide spread and standardized procedure. Starting in 1984, IDES was used to document each and every hip replacement and as of 1995 also for every knee arthroplasty performed. Norbert Gschwend became the driving authority in the clinic for standardizing documentation and regular long term follow-up intervals for all patients.

With increasing interest in patient reported outcomes (PROMs) a shift took place in the basic conception and electronic means (iPads) were introduced in 2012 to let patients complete their part of questionnaires, i.e. EQ-5D, OHS, OKS, UCLA & WOMAC while the clinical part was addressed in the same manner using HHS & KSS.

Optimizing user experience while answering routine questions and allowing for the physician to quickly enter required data without the numbing experience of ever same paper forms largely increased the return on information. This approach also guarantees for complete data sets, often a problem when using pen and paper.

Using these modern tools in combination with a refined recall procedure, we today show follow-up rates of well over 90% in the first post-operative years vs rates of 80% or less prior to introduction.

As of late 2012 the Swiss implant registry for knees & hips was introduced and here again we today use iPads with an app specifically designed to quickly document and register all operations on a daily base, reducing the chore of using paper or web based on line options from 3 to 10 minutes per operation to a mere 20 seconds, fully plausibilized and in this way never returned for corrections.

Pooling this data allows not only for generalized and stringent quality control but also facilitates spotting aberrant trends in the sense of an early warning system within our clinic with regard to procedures and implants.

Pioneering this approach to facilitate & perfect all documentation related procedures we aspire towards an elevated quality level in reporting to help sustain & guarantee patient satisfaction despite the high day-by-day volume.

Aims

Several studies have reported the safety and efficacy of subcapital re-alignment for patients with slipped capital femoral epiphysis (SCFE) using surgical dislocation of the hip and an extended retinacular flap. Instability of the hip and dislocation as a consequence of this surgery has only recently gained attention. We discuss this problem with some illustrative cases.

The use of joint-preserving surgery of the hip has been largely abandoned since the introduction of total hip replacement. However, with the modification of such techniques as pelvic osteotomy, and the introduction of intracapsular procedures such as surgical hip dislocation and arthroscopy, previously unexpected options for the surgical treatment of sequelae of childhood conditions, including developmental dysplasia of the hip, slipped upper femoral epiphysis and Perthes’ disease, have become available. Moreover, femoroacetabular impingement has been identified as a significant aetiological factor in the development of osteoarthritis in many hips previously considered to suffer from primary osteoarthritis.

As mechanical causes of degenerative joint disease are now recognised earlier in the disease process, these techniques may be used to decelerate or even prevent progression to osteoarthritis. We review the recent development of these concepts and the associated surgical techniques.

Cite this article: Bone Joint J 2014;96-B:5–18.

Femoroacetabular impingement (FAI) causes pain and chondrolabral damage via mechanical overload during movement of the hip. It is caused by many different types of pathoanatomy, including the cam ‘bump’, decreased head–neck offset, acetabular retroversion, global acetabular overcoverage, prominent anterior–inferior iliac spine, slipped capital femoral epiphysis, and the sequelae of childhood Perthes’ disease.

Both evolutionary and developmental factors may cause FAI. Prevalence studies show that anatomic variations that cause FAI are common in the asymptomatic population. Young athletes may be predisposed to FAI because of the stress on the physis during development. Other factors, including the soft tissues, may also influence symptoms and chondrolabral damage.

FAI and the resultant chondrolabral pathology are often treated arthroscopically. Although the results are favourable, morphologies can be complex, patient expectations are high and the surgery is challenging. The long-term outcomes of hip arthroscopy are still forthcoming and it is unknown if treatment of FAI will prevent arthrosis.

Introduction

Ectopic ossification (EO) at the acetabular rim has been suggested to be associated with pincer impingement and to lead to ossification of the labrum. However, this has never been substantiated with histological, radiographic and MRI findings in large cohorts of patients. We hypothesized that it is more a bone apposition of the acetabular rim and that it occurs more frequently in coxa profunda (CP) hips.

Background

Second-generation high-carbon CoCrMo-alloy metal-on-metal total hip arthroplasty (THA) was introduced in the late 1980s following reports of early loosening, impingement, pronounced wear, and hypersensitivity in the first-generation metal-on-metal articulations. There has been inconsistent data that specifically addresses the clinical performance and longevity of second-generation metal-on-metal THA. The purpose of this study was to evaluate the survival of second-generation metal-on-metal primary THA and to assess the influence of demographic factors on implant survival in a large patient cohort.

Peripheral nerve injury is an uncommon but serious complication of hip surgery that can adversely affect the outcome. Several studies have described the use of electromyography and intra-operative sensory evoked potentials for early warning of nerve injury. We assessed the results of multimodal intra-operative monitoring during complex hip surgery. We retrospectively analysed data collected between 2001 and 2010 from 69 patients who underwent complex hip surgery by a single surgeon using multimodal intra-operative monitoring from a total pool of 7894 patients who underwent hip surgery during this period. In 24 (35%) procedures the surgeon was alerted to a possible lesion to the sciatic and/or femoral nerve. Alerts were observed most frequently during peri-acetabular osteotomy. The surgeon adapted his approach based on interpretation of the neurophysiological changes. From 69 monitored surgical procedures, there was only one true positive case of post-operative nerve injury. There were no false positives or false negatives, and the remaining 68 cases were all true negative. The sensitivity for predicting post-operative nerve injury was 100% and the specificity 100%. We conclude that it is possible and appropriate to use this method during complex hip surgery and it is effective for alerting the surgeon to the possibility of nerve injury.

Concerns recently arose regarding hip resurfacing arthroplasty (HRA), mainly referring to the metal-on-metal articulation that results in increased metal ion concentrations and that may be associated with weird soft tissue reactions. Although a number of short-term reports highlighted excellent and encouraging outcomes after HRA, mid- to long-term follow-up studies are sparse in the current literature. This study aimed to determine the five-year results of HRA using the Durom^® prosthesis in the first consecutive 50 cases. We prospectively assessed clinical and radiographic data for all patients undergoing HRA with this implant. Follow-ups were scheduled at six weeks, one year, two years and five years after surgery. All complications, revisions and failures were noted. Harris Hip Scores (HHS) and the range of motion (ROM) were determined preoperatively and at each follow-up. Oxford Hip Scores (OHS) and University of California at Los Angeles (UCLA) activity levels were determined at the last control. Comparisons were performed using paired t-tests after testing for normal distribution. The cohort comprised 13 women and 36 men (50 hips) with a mean age of 53.3 ± 10.7 years and a mean BMI of 25.9 ± 3.7 kg/m2. After a mean follow-up of 60.5 ± 2.3 months five hips had to be revised, corresponding to a resvision rate of 10%. There occurred two femoral neck fractures (after two and eleven months) and one aseptic loosening of the femoral component (after 68 months). One implant was exchanged to a conventional stem-type design due to persistent hip pain (after eight months), and one hip underwent a femoral offset correction due to a symptomatic impingement between the neck and the cup (after 29 months). There occurred no intra- or other postoperative complications. Clinically, ROM significantly improved after surgery. Hip flexion increased from 91.1 ± 15.8° to 98.9 ± 6.5° (p=0.0007), internal rotation from 5.5 ± 6.9° to 11.1 ± 8.1° (p=0.0005), external rotation from 19.2 ± 12.5° to 28.8 ± 9.1° (p=0.0001), and abduction from 27.3 ± 10.5° to 40.2 ± 11.0° (p< 0.0001). The HHS significantly increased from 55.9 ± 12.3 points to 96.5 ± 8.5 points. The OHS averaged 14.3 ± 3.0 points, and UCLA activity levels averaged 7.7 ± 1.7. The present results demonstrate that despite satisfactory clinical outcomes in terms of patient scores and ROM, the high revision rate of 10% after a mid-term follow-up is disappointing.