Aims. Iliopsoas pathology is a relatively uncommon cause of pain following total hip arthroplasty (THA), typically presenting with symptoms of groin pain on active flexion and/or extension of the hip. A variety of conservative and surgical treatment options have been reported. In this retrospective cohort study, we report the incidence of iliopsoas pathology and treatment outcomes. Methods. A retrospective review of 1,000 patients who underwent THA over a five-year period was conducted, to determine the incidence of patients diagnosed with iliopsoas pathology. Outcome following non-surgical and surgical management was assessed. Results. In all, 24 patients were diagnosed as having developed symptomatic iliopsoas pathology giving an incidence of 2.4%. While the mean age for receiving a THA was 65 years, the mean age for developing iliopsoas pathology was 54 years (28 to 67). Younger patients and those receiving THA for conditions other than primary osteoarthritis were at a higher risk of developing this complication. Ultrasound-guided steroid injection/physiotherapy resulted in complete resolution of symptoms in 61% of cases, partial resolution in 13%, and no benefit in 26%. Eight out of 24 patients (who initially responded to injection) subsequently underwent surgical intervention including
We have reviewed a group of patients with iliopsoas impingement after total hip replacement with radiological evidence of a well-fixed malpositioned or oversized acetabular component. A consecutive series of 29 patients (30 hips) was assessed. All had undergone a trial of conservative management with no improvement in their symptoms. Eight patients (eight hips) preferred continued conservative management (group 1), and 22 hips had either an iliopsoas
Iliopsoas impingement occurs in 4% to 30% of patients after undergoing total hip arthroplasty (THA). Despite a relatively high incidence, there are few attempts at modelling impingement between the iliopsoas and acetabular component, and no attempts at modelling this in a representative cohort of subjects. The purpose of this study was to develop a novel computational model for quantifying the impingement between the iliopsoas and acetabular component and validate its utility in a case-controlled investigation. This was a retrospective cohort study of patients who underwent THA surgery that included 23 symptomatic patients diagnosed with iliopsoas tendonitis, and 23 patients not diagnosed with iliopsoas tendonitis. All patients received postoperative CT imaging, postoperative standing radiography, and had minimum six months’ follow-up. 3D models of each patient’s prosthetic and bony anatomy were generated, landmarked, and simulated in a novel iliopsoas impingement detection model in supine and standing pelvic positions. Logistic regression models were implemented to determine if the probability of pain could be significantly predicted. Receiver operating characteristic curves were generated to determine the model’s sensitivity, specificity, and area under the curve (AUC).Aims
Methods
Dislocation remains a leading cause of failure following revision total hip arthroplasty (THA). While dual-mobility (DM) bearings have been shown to mitigate this risk, options are limited when retaining or implanting an uncemented shell without modular DM options. In these circumstances, a monoblock DM cup, designed for cementing, can be cemented into an uncemented acetabular shell. The goal of this study was to describe the implant survival, complications, and radiological outcomes of this construct. We identified 64 patients (65 hips) who had a single-design cemented DM cup cemented into an uncemented acetabular shell during revision THA between 2018 and 2020 at our institution. Cups were cemented into either uncemented cups designed for liner cementing (n = 48; 74%) or retained (n = 17; 26%) acetabular components. Median outer head diameter was 42 mm. Mean age was 69 years (SD 11), mean BMI was 32 kg/m2 (SD 8), and 52% (n = 34) were female. Survival was assessed using Kaplan-Meier methods. Mean follow-up was two years (SD 0.97).Aims
Methods
Hip arthroscopy has gained prominence as a primary surgical intervention for symptomatic femoroacetabular impingement (FAI). This study aimed to identify radiological features, and their combinations, that predict the outcome of hip arthroscopy for FAI. A prognostic cross-sectional cohort study was conducted involving patients from a single centre who underwent hip arthroscopy between January 2013 and April 2021. Radiological metrics measured on conventional radiographs and magnetic resonance arthrography were systematically assessed. The study analyzed the relationship between these metrics and complication rates, revision rates, and patient-reported outcomes.Aims
Methods
Total hip arthroplasty (THA) in patients with post-polio residual paralysis (PPRP) is challenging. Despite relief in pain after THA, pre-existing muscle imbalance and altered gait may cause persistence of difficulty in walking. The associated soft tissue contractures not only imbalances the pelvis, but also poses the risk of dislocation, accelerated polyethylene liner wear, and early loosening. In all, ten hips in ten patients with PPRP with fixed pelvic obliquity who underwent THA as per an algorithmic approach in two centres from January 2014 to March 2018 were followed-up for a minimum of two years (2 to 6). All patients required one or more additional soft tissue procedures in a pre-determined sequence to correct the pelvic obliquity. All were invited for the latest clinical and radiological assessment.Aims
Methods
Adult patients with history of childhood infection pose a surgical challenge for total hip arthroplasty (THA) due to distorted bony anatomy, soft-tissue contractures, risk of reinfection, and relatively younger age. Therefore, the purpose of the present study was to determine clinical outcome, reinfection rate, and complications in patients with septic sequelae after THA. A retrospective analysis was conducted of 91 cementless THAs (57 male and 34 female) performed between 2008 and 2017 in patients who had history of hip infection during childhood. Clinical outcome was measured using Harris Hip Score (HHS) and Modified Merle d’Aubigne and Postel (MAP) score, and quality of life (QOL) using 12-Item Short Form Health Survey Questionnaire (SF-12) components: Physical Component Score (PCS) and Mental Component Score (MCS); limb length discrepancy (LLD) and radiological assessment of the prosthesis was performed at the latest follow-up. Reinfection and revision surgery after THA for any reason was documented.Aims
Methods
Persistent groin pain after seemingly successful
total hip replacement (THR) appears to have become more common.
Recent studies have indicated a high incidence after metal-on-polyethylene
and metal-on-metal conventional THR and it has been documented in
up to 18% of patients after metal-on-metal resurfacing. There are many
causes, including acetabular loosening, stress fracture, and iliopsoas
tendonitis and impingement. The evaluation of this problem requires
a careful history and examination, plain radiographs and an algorithmic approach
to special diagnostic imaging and tests. Non-operative treatment
is not usually successful. Specific operative treatment depending
on the cause of the pain usually involves revision of the acetabular
component, iliopsoas
Despite advances in the treatment of paediatric hip disease, adolescent and young adult patients can develop early onset end-stage osteoarthritis. The aims of this study were to address the indications and medium-term outcomes for total hip arthroplasty (THA) with ceramic bearings for teenage patients. Surgery was performed by a single surgeon working in the paediatric orthopaedic unit of a tertiary referral hospital. Databases were interrogated from 2003 to 2017 for all teenage patients undergoing THA with a minimum 2.3 year follow-up. Data capture included patient demographics, the underlying hip pathology, number of previous surgeries, and THA prostheses used. Institutional ethical approval was granted to contact patients for prospective clinical outcomes and obtain up-to-date radiographs. In total, 60 primary hips were implanted in 51 patients (35 female, 16 male) with nine bilateral cases. The mean age was 16.7 years (12 to 19) and mean follow-up was 9.3 years (2.3 to 16.8).Aims
Methods
Complex total hip arthroplasty (THA) with subtrochanteric shortening osteotomy is necessary in conditions other than developmental dysplasia of the hip (DDH) and septic arthritis sequelae with significant proximal femur migration. Our aim was to evaluate the hip centre restoration with THAs in these hips. In all, 27 THAs in 25 patients requiring THA with femoral shortening between 2012 and 2019 were assessed. Bilateral shortening was required in two patients. Subtrochanteric shortening was required in 14 out of 27 hips (51.9%) with aetiology other than DDH or septic arthritis. Vertical centre of rotation (VCOR), horizontal centre of rotation, offset, and functional outcome was calculated. The mean followup was 24.4 months (5 to 92 months).Aims
Methods
Patients with neuromuscular imbalance who require
total hip arthroplasty (THA) present particular technical problems
due to altered anatomy, abnormal bone stock, muscular imbalance
and problems of rehabilitation. In this systematic review, we studied articles dealing with THA
in patients with neuromuscular imbalance, published before April
2017. We recorded the demographics of the patients and the type
of neuromuscular pathology, the indication for surgery, surgical
approach, concomitant soft-tissue releases, the type of implant
and bearing, pain and functional outcome as well as complications
and survival. Recent advances in THA technology allow for successful outcomes
in these patients. Our review suggests excellent benefits for pain
relief and good functional outcome might be expected with a modest
risk of complication. Cite this article:
Hip and groin injuries are common in athletes
who take part in high level sports. Adductor muscle tendon injuries represent
a small but important number of these injuries. Avulsion of the
tendons attached to the symphysis pubis has previously been described:
these can be managed both operatively and non-operatively. We describe
an uncommon variant of this injury, namely complete avulsion of
the adductor sleeve complex: this includes adductor longus, pectineus
and rectus abdominis. We go on to describe a surgical technique
which promotes a full return to the pre-injury level of sporting
activity. Over a period of ten years, 15 high-level athletes with an MRI-confirmed
acute adductor complex avulsion injury (six to 34 days old) underwent
surgical repair. The operative procedure consisted of anatomical
re-attachment of the avulsed tissues in each case and mesh reinforcement
of the posterior inguinal wall in seven patients. All underwent a
standardised rehabilitation programme, which was then individualised
to be sport-specific. One patient developed a superficial wound infection, which was
successfully treated with antibiotics. Of the 15 patients, four
complained of transient local numbness which resolved in all cases.
All patients (including seven elite athletes) returned to their
previous level of participation in sport. Cite this article:
Vascular injuries during total hip arthroplasty
(THA) are rare but when they occur, have serious consequences. These have
traditionally been managed with open exploration and repair, but
more recently there has been a trend towards percutaneous endovascular
management. We performed a systematic review of the literature to assess
if this change in trend has led to an improvement in the overall
reported rates of morbidity and mortality during the last 22 years
in comparison with the reviews of the literature published previously. We found a total of 61 articles describing 138 vascular injuries
in 124 patients. Injuries because of a laceration were the most
prevalent (n = 51, 44%) and the most common presenting feature,
when recorded, was bleeding (n = 41, 53.3%). Delay in diagnosis
was associated with the type of vascular lesion (p <
0.001) and
the clinical presentation (p = 0.002). Open exploration and repair was the most common form of management,
however percutaneous endovascular intervention was used in one third
of the injuries and more constantly during the last 13 years. The main overall reported complications included death (n = 9,
7.3%), amputation (n = 2, 1.6%), and persistent ischaemia (n = 9,
7.3%). When compared with previous reviews there was a similar rate
of mortality but lower rates of amputation and permanent disability,
especially in patients managed by endovascular strategies. Cite this article:
The aim of this cadaver study was to identify
the change in position of the sciatic nerve during arthroplasty
using the posterior surgical approach to the hip. We investigated
the position of the nerve during this procedure by dissecting 11
formalin-treated cadavers (22 hips: 12 male, ten female). The distance
between the sciatic nerve and the femoral neck was measured before
and after dislocation of the hip, and in positions used during the
preparation of the femur. The nerve moves closer to the femoral
neck when the hip is flexed to >
30° and internally rotated to 90° (90°
IR). The mean distance between the nerve and femoral neck was 43.1
mm (standard deviation ( This study demonstrates that the sciatic nerve becomes closer
to the operative field during hip arthroplasty using the posterior
approach with progressive flexion of the hip. Cite this article:
Degenerative problems of the hip in patients
with childhood and adult onset neuromuscular disorders can be challenging
to treat. Many orthopaedic surgeons are reluctant to recommend total
hip replacement (THR) for patients with underlying neuromuscular
disorders due to the perceived increased risks of dislocation, implant loosening,
and lack of information about the functional outcomes and potential
benefits of these procedures in these patients. Modular femoral
components and alternative bearings which facilitate the use of
large femoral heads, constrained acetabular components and perhaps
more importantly, a better understanding about the complications
and outcomes of THR in the patient with neuromuscular disorders,
make this option viable. This paper will review the current literature
and our experience with THR in the more frequently encountered neuromuscular
disorders. Cite this article:
In this retrospective study, we investigated
the results of revision total hip replacement (THR) using a cemented long-stemmed
Exeter femoral component, with a minimum length of 205 mm in patients
with extensive femoral bone defects. The study included 37 consecutive
patients with a mean age of 76 years (39 to 93) and a mean follow-up
of nine years (5 to 16). A total of 26 patients (70%) had a pre-operative
Endo-Klinik score of 3 or 4. Impaction bone grafting was used in
24 patients (65%). At the time of evaluation, 22 patients (59%)
were still alive and were evaluated clinically and radiologically.
A total of 14 patients died during follow-up and their data were
included until the time of their death. One reconstruction failed
after five years and five months owing to recurrent dislocation:
the hip was converted to an excision arthroplasty. Intra-operative
fractures or fissures were encountered in nine patients (24%), but
none occurred during impaction of the bone graft. Post-operative
peri-prosthetic fractures occurred in two patients (5%); both were
treated with plate fixation. At nine years, survival with the endpoint
of all-cause re-revision was 96.3% (95% CI 76.4 to 99.5); including
re-operations for any reason, it was 80.7% (95% CI 56.3 to 92.3%).
There were no re-revisions for aseptic loosening. The survival of long stem cemented femoral components following
revision THR is satisfactory in a fragile population with extensive
femoral defects. Cite this article:
Total hip replacement (THR) still is a rare intervention
in many African countries. In Burkina Faso it is not performed on
a regular basis. A visiting programme for THR was started in a district
hospital with no previous relevant experience. In this paper we
present an analysis of the surgical technical problems and peri-operative
complications of 152 THRs in 136 patients and three bipolar hemiarthroplasties
in three patients undertaken in this new programme with limited
orthopaedic equipment. There were 86 male and 53 female patients
with a mean age of 49 years (21 to 78). We identified 77 intra-operative
technical problems in 51 operations. There were 24 peri-operative complications
in 21 patients, 17 of which were bony in nature. So far, ten revision
THRs have been performed in nine patients. Regular analysis of the technical problems and complications
was used to improve quality, and we identified patient selection
adapted to the local circumstances as important to avoid complications.
Our reflections on the problems encountered in initiating such a
programme may be of help to other teams planning similar projects. Cite this article:
There are few reports describing the technique
of managing acetabular protrusio in primary total hip replacement. Most
are small series with different methods of addressing the challenges
of significant medial and proximal migration of the joint centre,
deficient medial bone and reduced peripheral bony support to the
acetabular component. We describe our technique and the clinical
and radiological outcome of using impacted morsellised autograft
with a porous-coated cementless cup in 30 primary THRs with mild
(n = 8), moderate (n = 10) and severe (n = 12) grades of acetabular
protrusio. The mean Harris hip score had improved from 52 pre-operatively
to 85 at a mean follow-up of 4.2 years (2 to 10). At final follow-up,
27 hips (90%) had a good or excellent result, two (7%) had a fair
result and one (3%) had a poor result. All bone grafts had united
by the sixth post-operative month and none of the hips showed any
radiological evidence of recurrence of protrusio, osteolysis or
loosening. By using impacted morsellised autograft and cementless
acetabular components it was possible to achieve restoration of
hip mechanics, provide a biological solution to bone deficiency
and ensure long-term fixation without recurrence in arthritic hips
with protrusio undergoing THR. Cite this article:
Total hip replacement for developmental hip dysplasia
is challenging. The anatomical deformities on the acetabular and
femoral sides are difficult to predict. The Crowe classification
is usually used to describe these cases – however, it is not a very
helpful tool for pre-operative planning. Small acetabular components,
acetabular augments, and modular femoral components should be available
for all cases. Regardless of the Crowe classification, the surgeon must
be prepared to perform a femoral osteotomy for shortening, or to
correct rotation, and/or angulation. Cite this article:
The aim of this review is to evaluate the current
available literature evidencing on peri-articular hip endoscopy
(the third compartment). A comprehensive approach has been set on
reports dealing with endoscopic surgery for recalcitrant trochanteric
bursitis, snapping hip (or coxa-saltans; external and internal),
gluteus medius and minimus tears and endoscopy (or arthroscopy)
after total hip arthroplasty. This information can be used to trigger
further research, innovation and education in extra-articular hip
endoscopy.
When performing total hip replacement (THR) in high dislocated hips, the presence of soft-tissue contractures means that most surgeons prefer to use a femoral shortening osteotomy in order to avoid the risk of neurovascular damage. However, this technique will sacrifice femoral length and reduce the extent of any leg-length equalisation. We report our experience of 74 THRs performed between 2000 and 2008 in 65 patients with a high dislocated hip without a femoral shortening osteotomy. The mean age of the patients was 55 years (46 to 72) and the mean follow-up was 42 months (12 to 78). All implants were cementless except for one resurfacing hip implant. We attempted to place the acetabular component in the anatomical position in each hip. The mean Harris hip score improved from 53 points (34 to 74) pre-operatively to 86 points (78 to 95) at final follow-up. The mean radiologically determined leg lengthening was 42 mm (30 to 66), and the mean leg-length discrepancy decreased from 36 mm (5 to 56) pre-operatively to 8.5 mm (0 to 18) postoperatively. Although there were four (5%) post-operative femoral nerve palsies, three had fully resolved by six months after the operation. No loosening of the implant was observed, and no dislocations or infections were encountered. Total hip replacement without a femoral shortening osteotomy proved to be a safe and effective surgical treatment for high dislocated hips.
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.
We evaluated all cases involving the combined use of a subtrochanteric derotational femoral shortening osteotomy with a cemented Exeter stem performed at our institution. With severe developmental dysplasia of the hip an osteotomy is often necessary to achieve shortening and derotation of the proximal femur. Reduction can be maintained with a 3.5 mm compression plate while the implant is cemented into place. Such a plate was used to stabilise the osteotomy in all cases. Intramedullary autograft helps to prevent cement interposition at the osteotomy site and promotes healing. There were 15 female patients (18 hips) with a mean age of 51 years (33 to 75) who had a Crowe IV dysplasia of the hip and were followed up for a mean of 114 months (52 to 168). None was lost to follow-up. All clinical scores were collected prospectively. The Charnley modification of the Merle D’Aubigné-Postel scores for pain, function and range of movement showed a statistically significant improvement from a mean of 2.4 (1 to 4), 2.3 (1 to 4), 3.4 (1 to 6) to 5.2 (3 to 6), 4.4 (3 to 6), 5.2 (4 to 6), respectively. Three acetabular revisions were required for aseptic loosening; one required femoral revision for access. One osteotomy failed to unite at 14 months and was revised successfully. No other case required a femoral revision. No postoperative sciatic nerve palsy was observed. Cemented Exeter femoral components perform well in the treatment of Crowe IV dysplasia with this procedure.
We undertook a prospective pilot study to determine whether arthroscopic surgery through the central compartment of the hip was effective in the management of a snapping iliopsoas tendon. Seven patients were assessed pre-operatively and at three, six, 12 and 24 months after operation. This included the assessment of pain on a visual analogue scale (VAS) and function using the modified Harris hip score. All the patients had resolution of snapping post-operatively and this persisted at follow-up at two years. The mean VAS score for pain fell from 7.7 (6 to 10) pre-operatively to 4.3 (0 to 10) by three months (p = 0.051), and to 3.6 (1 to 8) (p = 0.015), 2.4 (0 to 8) (p = 0.011) and 2.4 (0 to 8) (p = 0.011) by six, 12 and 24 months, respectively. The mean modified Harris hip score increased from 56.1 (13.2 to 84.7) pre-operatively to 88.4 (57.2 to 100) at one year (p = 0.018) and to 87.9 (49.5 to 100) at two years (p = 0.02). There were no complications and no weakness occurred in the musculature around the hip. Our findings suggest that this treatment is effective and would support the undertaking of a larger study comparing this procedure with other methods of treatment.
Between November 1997 and December 2000 we performed 27 total hip replacements in 22 patients with high congenital dislocation of the hip using porous tantalum monoblock acetabular components implanted in the true acetabular bed. Clinical and radiological evaluation was performed at regular intervals for a mean of 10.2 years (8.5 to 12). The mean Harris Hip Score improved from 48.3 (15 to 65) pre-operatively to 89.5 (56 to 100) at the final follow-up. The mean Oxford Hip Score was 49.5 (35 to 59) pre-operatively and decreased to 21.2 (12 to 48) at one year and 15.2 (10 to 28) at final follow-up. Migration of the acetabular component was assessed with the EBRA software system. There was a mean migration of 0.68 mm (0.49 to 0.8) in the first year and a mean 0.89 mm (0.6 to 0.98) in the second year, after excluding one initial excessive migration. No revision was necessary for any reason, no acetabular component became loose, and no radiolucent lines were observed at the final follow-up. The porous tantalum monoblock acetabular component is an implant offering adequate initial stability in conjunction with a modulus of elasticity and porosity close to that of cancellous bone. It favours bone ingrowth, leading to good mid-term results.
Implantation of a large-diameter femoral head prosthesis with a metal-on-metal bearing surface reduces the risk of dislocation, increases the range of movement, minimises the risk of impingement and, in theory, results in little wear. Between February 2004 and March 2007 we implanted 100 consecutive total hip replacements with a metal-on-metal bearing and a large femoral head into 92 patients. There were 51 men and 41 women with a mean age of 50 years (18 to 70) at the time of surgery. Outcome was assessed using the Western Ontario McMaster University osteoarthritis index and the Harris hip score as well as the Devane activity score. These all improved significantly (p <
0.0001). At the last follow-up there were no cases of dislocation, no impingement, a good range of movement and no osteolysis, but seven revisions, two for infection and five for aseptic loosening. The probability of groin pain increased if the other acetabular component inclination exceeded 50° (p = 0.0007). At 4.8 years of follow-up, the projected survival of the Durom acetabular component, with revision for any reason, was 92.4% ( The design of the component made it difficult both to orientate and seat, which when combined with a poor porous coating, produced unpredictable fixation and a low survival at five years.
We have reviewed 54 patients who had undergone 61 total hip replacements using bulk femoral autografts to augment a congenitally dysplastic acetabulum. There were 52 women and two men with a mean age of 42.4 years (29 to 76) at the time of the index operation. A variety of different prostheses was used: 28 (45.9%) were cemented and 33 (54.1%) uncemented. The graft technique remained unchanged throughout the series. Follow-up was at a mean of 8.3 years (3 to 20). The Hospital for Special Surgery hip score improved from a mean of 10.7 (4 to 18) pre-operatively to a mean of 35 (28 to 38) at follow-up. The position of the acetabular component was anatomical in 37 hips (60.7%), displaced less than 1 cm in 20 (32.7%) and displaced more than 1 cm in four (6.6%). Its cover was between 50% and 75% in 34 hips (55.7%) and less than 50% in 25 (41%). In two cases (3.3%), it was more than 75%. There was no graft resorption in 36 hips (59%), mild resorption in 21 (34%) and severe resorption in four (6%). Six hips (9.8%) were revised for aseptic loosening. The overall rate of loosening and revision was 14.8%. Overall survival at 8.3 years was 93.4%. The only significant factor which predicted failure was the implantation of the acetabular component more than 1 cm from the anatomical centre of rotation of the hip.
A clinical and radiological study was conducted on 97 total hip replacements performed for congenital hip dislocation in 79 patients between 1989 and 1998 using a three-dimensional custom-made cementless stem. The mean age at operation was 48 years (17 to 72) and the mean follow-up was for 123 months (83 to 182). According to the Crowe classification, there were 37 class I, 28 class II, 13 class III and 19 class IV hips. The mean leg lengthening was 25 mm (5 to 58), the mean pre-operative femoral anteversion was 38.6° (2° to 86°) and the mean correction in the prosthetic neck was −23.6° (−71° to 13°). The mean Harris hip score improved from 58 (15 to 84) to 93 (40 to 100) points. A revision was required in six hips (6.2%). The overall survival rate was 89.5% (95% confidence interval 89.2 to 89.8) at 13 years when two hips were at risk. This custom-made cementless femoral component, which can be accommodated in the abnormal proximal femur and will correct the anteversion and frontal offset, provided good results without recourse to proximal femoral corrective osteotomy.