Medial opening wedge valgus intertrochanteric osteotomy for femoral neck nonunion: a femoral anatomy-preserving surgical approach

Introduction

Valgus intertrochanteric osteotomy (VITO) is a femoral head-preserving surgical intervention performed in cases of femoral neck nonunion to realign and stabilise the femoral neck. ¹ This management technique is usually preferred for younger, active patients. It is regarded as one of the most effective head salvage procedures for femoral neck nonunion, whether resulting from a failed fixation or a neglected non-union of femoral neck fracture.^2,3 VITO aims to improve fracture biomechanics by converting shear into compressive forces and restoring blood flow to the femoral head by correcting alignment. ¹

Displacement osteotomies, such as McMurray’s osteotomy, are primarily considered salvage procedures that have largely fallen out of favour due to their considerable distortion of the proximal femoral anatomy and the resultant limb shortening. ⁴ The angular osteotomies (intertrochanteric or subtrochanteric) alter the head-shaft relationship, compromise the contact at the osteotomy surface and result in significant medialisation of the shaft to support the femoral head, thus altering the proximal femur anatomy during valgisation.^5,6 Despite improving the biomechanics, the altered proximal femoral anatomy complicates revision to hip arthroplasty when head osteosynthesis fails. Our innovative approach addresses the shortcomings of conventional methods through a no-wedge technique that opens the medial side, facilitating equal limb length and minimal alterations to the proximal femoral anatomy. However, the use of blade plate requires precise surgical technique and limited flexibility during the operation. An incorrect blade trajectory can jeopardise alignment and contact at the osteotomy site.

This study aims to describe the surgical technique of medial opening wedge valgus intertrochanteric osteotomy (VITO) and evaluate the changes in neck-shaft angle, duration until radiographic union, functional outcomes measured by the Harris Hip Score (HHS), and incidence of complications among patients who have undergone this innovative approach. It emphasises the restoration of hip biomechanics and union rates.

Patients and methods

This study included a consecutive series of 18 patients treated at a level 1 trauma centre between January 2007 and January 2022. We included all patients with untreated or previously operated neck of femur nonunion who were deemed to benefit from head osteosynthesis.

Surgical technique

Patient positioning, anaesthesia and reduction

The patient is positioned on a traction table with the opposite leg in a boot, flexed and abducted. General or regional anaesthesia is administered, depending on the patient’s overall health; however, we prefer general anaesthesia, especially when using a traction table. The neck-shaft angle (NSA) of long-standing nonunion or failed femoral neck fixations is templated preoperatively and/or intraoperatively after the implants are removed, and traction is applied to achieve the most anatomical reduction possible (usually matched to the neck shaft angle of the opposite side). We have been using the TraumaCad software (Brainlab, Germany) since 2019, and the AO Templates prior to 2019. Excessive traction is avoided as it may cause valgus at the fracture site, although it could help reduce Pauwels’s angle at the fracture site. Open reduction is not performed as it may further compromise the blood supply.

Surgical approach

A lateral incision is made from the tip of the greater trochanter, extending down the femoral shaft. The fascia is dissected in line with the incision. The vastus lateralis tendon is detached from its proximal origin and posterior attachment, and the muscle is retracted anteromedially. The guide wire is inserted from the lateral wall towards the Ward’s triangle. The seating chisel is carefully inserted using the guide wire, alternating the image intensifier between anteroposterior (AP) and lateral views to prepare the channel for the blade (Figure 1(a)–(c)).

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Figure 1.

(a) Preoperative AP (anteroposterior) radiograph of the right hip with non-union of neck of femur; (b) Intraoperative figure shows guide wire and seating chisel inserted (Inset image- AP image intensifier (II) view); (c) Intraoperative image with osteotome before completion of medial cortex break; (d) Intraoperative image of insertion of double-angled 120° blade plate (Inset image – AP image intensifier shows the plate off the lateral cortex); (e) Intraoperative image with the plate clamped down with 2 Verbrugge clamps to the lateral cortex (Inset image – AP image intensifier view of the Verbrugge clamps. Note the medial opening of the osteotomy); (f) and (g) Final AP and lateral II views.

Osteotomy, realignment and fixation

The intertrochanteric osteotomy begins on the lateral cortex at the level of the inferior angle of the plate, is directed superiorly, and exits closer to the neck medially (Figure 1(d)). The osteotomy is typically parallel to the chisel (Figure 1(e)). This is performed with an oscillating saw, ensuring that the medial hinge remains intact. The chisel is removed. With 10° or 20° corrections, a 110° or 120° angled 4-hole osteotomy is generally sufficient. The lateral cortex of the femur is reduced to the plate with a Verbrugge clamp, which frequently breaks the medial hinge, completing the osteotomy (Figure 1(e)). The proximal fragment may have an inferior spike that could hinder reduction. If necessary, this spike can be osteotomised to achieve an acceptable alignment. Finally, screws are inserted to secure fixation. (Figure 1(f) and (g)).

Closure and postoperative care

The layers of muscle and fascia are meticulously closed, and the skin incision is sutured. Postoperatively, range of motion exercises for the hip, knee, and upper body conditioning for crutch use are started. The patient can bear partial weight using crutches or a walker frame for 6 weeks and progress to protected weight-bearing for an additional 6 weeks. Progression to full weight-bearing is allowed 3 months after radiographic confirmation of osteotomy healing.

Outcomes

Patient demographics and fracture-related details, including previous treatment, duration of injury, and associated injuries (nonunion/ malunion), were also acquired from the hospital records. The neck-shaft angle (NSA) for both hips and the corrected valgus angle was measured for all the patients. All patients were followed until either fracture healing or conversion to total hip arthroplasty (THA). Bony union was defined radiologically as bony trabeculae bridging the defect and increased density at either one or both sides of the fracture line, assessed by 2 authors. ⁷ The clinical outcome was evaluated based on the HHS. ⁸ Complications such as fixation failure, wound complications, and conversion to THA were also recorded.

Results

There were 14 male and 4 female patients in this study. 8 patients had neglected nonunion, and 10 patients had developed nonunion after fixation with either cannulated screws or dynamic hip screws (DHS). The average age of these patients was 39 years (range: 16–51). The average duration of nonunion was 10.7 months (range: 1–60).

16 out of 18 patients with at least 24 months of follow-up were included for outcome analysis. 1 patient died in the immediate postoperative period, and 1 with only 6 months of follow-up was excluded. The average duration of follow-up was 64 months (range: 24–140). The average NSA correction achieved was 16° (range: 10–25°). The difference in the NSA in patients with over-correction (valgus) (12/16) was 12° (range: 3–24°), and in patients with under-correction (varus) (4/16), was 7° (range: 5–10°). There was loss of NSA in 3 patients at final follow-up (Table 1).

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Table 1.

Patient list with demographics and results.

Sl No	Age in years	Sex	NU reason	NU duration in months	NSA uninjured side in degrees	Pre-op NSA on the injured side in degrees	Post-op NSA in degrees	Correction angle (pre- and post-surgery) in degrees	NSA difference in degrees between normal/operated side	NSA at final follow up in months	Follow-up in months	Pre-op HHS	Post-op HHS	HHS grade	Complications
1	46	M	NEGLECTED	2	135	124	139	15	4	139	120	40	92	EXCELLENT	Nil
2	29	F	NEGLECTED	12	134	99	124	25	−10	124	96	56	96	EXCELLENT	Nil
3	51	M	Failed cannulated screws	2.5	135	130	142	12	7	125	24	28	0		THA - 24 months
4	49	F	NEGLECTED	1	132	137	153	16	21	110	140	56	0		THA - 6 months (Blade plate cut out)
5	48	F	NEGLECTED	1	126	124	139	15	13	139	88	52	92	EXCELLENT	Nil
6	47	M	NEGLECTED	20	122	109	135	26	13	135	85	26	94	EXCELLENT	Nil
7	31	M	Failed cannulated screws	60	128	99	139	40	11	139	60	39	86	GOOD	Nil
8	51	M	Failed DHS	3	126	113	143	30	17	90	9	52	0		THA - 9 months (Broken plate)
9	44	M	CANN SCREWS	24	135	115	127	12	−8	127	72	55	90	EXCELLENT	AVN no collapse at 16 months
10	25	M	Failed DHS	1	134	114	129	15/15	−5	129	36	41	89	GOOD	Implant failure revised to CBP
11	43	M	Failed cannulated screws	7	130	134	154	20	24	154	48	55	86	GOOD	AVN at 6 months no collapse
12	43	M	Failed DHS	6	132	112	135	23	3	135	48	57	92	EXCELLENT	AVN with collapse at 6 months
13	19	M	NEGLECTED	24	125	123	148	25	23	148	72	55	94	EXCELLENT	Nil
14	36	M	Failed cannulated screws	8	130	116	140	24	10	140	48	42	94	EXCELLENT	Nil
15	39	M	Failed cannulated screws	3	130	111	133	22	3	133	48	54	100	EXCELLENT	Nil
16	33	FM	Failed DHS	7	140	125	135	10	−5	135	25	26.6	99	EXCELLENT	Nil
17	49	M	Failed cannulated screws	5	138	120		14			0	46	0		Postop death
18	16	M	NEGLECTED	6	132	135	160	25	28	160	6	57	94	EXCELLENT	Nil

NU, non-union; NSA, neck shaft angle, NA, not applicable; HHS, Harris Hip Score; DHS, dynamic hip screw; THA, total hip arthroplasty; AVN, avascular necrosis; ABP, angled blade plate.

All patients achieved a union of both the femoral neck and osteotomy site. The average preoperative HHS was 46 (range: 26–57), which improved to a postoperative score of 92 (range: 89–100) in the patients who had successful VITO. The HHS was excellent in 10 patients (62%) and good in 3 (19%). 3 patients (19%) were revised to THR using primary stems at 6, 9, and 24 months secondary to implant cut-out, implant breakage, and AVN, respectively. All 3 patients had no immediate or delayed complications at the time of conversion to hip arthroplasty (Figure 2). 1 patient (6%, 1/17) had implant breakage 6 months after the valgus osteotomy and had to undergo redo fixation with an angled blade plate (ABP). At the final follow-up, all these patients remained free of complications. (Figures 3 and 4).

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Figure 2.

(a) AP radiograph of 1 month neglected neck of femur in a 49-year-old female; (b) Immediate postoperative AP radiograph after valgus osteotomy; (c) 6 months follow-up shows a superior cutout of blade plate; (d) AP radiograph after conversion to total hip arthroplasty. Please note the well-preserved femoral shaft anatomy.

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Figure 3.

(a) AP radiograph of 20 months neglected neck of femur non-union in a 47-year-old male; (b) Immediate postoperative AP radiograph after valgus osteotomy; (c) and (d) AP and lateral radiograph at 7 years with good union and excellent Harris Hip Score (94).

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Figure 4.

(a) AP template radiograph of 39-year-old male with varus collapse and non-union of right neck of femur; (b) Intraoperative AP image intensifier view; (c) and (d) AP and lateral radiograph at 4 years with good union and excellent Harris Hip Score (100).

3 patients (18%) had AVN (avascular necrosis) with femoral head collapse in 2 patients and 1 without collapse. These 3 patients had femoral head perforation with failed neck osteosynthesis (cannulated screws – 2; DHS – 1). All 3 patients were mobile and had good to excellent HHS.

Discussion

Our described technique of medial opening wedge valgus intertrochanteric osteotomy (VITO) restores hip biomechanics and demonstrates excellent union rates comparable to previous techniques. ¹ In our series, 81% (13/16) had united at the latest follow-up. Of these 13 patients, 3 patients had developed avascular necrosis (AVN) of the femoral head on follow-up but remained pain-free. 3 patients had failed osteosynthesis and were converted to total hip replacement surgery.

Valgus osteotomy for femoral neck nonunion is a technically demanding procedure that requires careful planning and precise execution. The experience of the surgical team and the patient’s overall health are crucial factors for achieving a successful outcome. The two main types of osteotomy are displacement and angular osteotomies. Displacement osteotomies are currently unpopular because they distort the proximal femur, shorten the limb, and do not aim to heal fractures.^9,10 Valgus osteotomies can be classified as either intertrochanteric or subtrochanteric. Valgus lateral closing wedge osteotomy alters the forces acting at the fracture site by redistributing the mechanical stress, reducing the shear and increasing the compressive ones. ¹ However, previous techniques result in medialisation of the distal fragment during valgisation, which leads to alteration in the anatomy of the femoral canal.^{6,11 –14}

The advantages of our medial opening wedge valgus intertrochanteric osteotomy include minimal alteration of femoral anatomy, good bone healing, and minimal blood supply damage. The oblique osteotomy creates a larger surface area in cancellous bone, facilitating greater angular correction and promoting effective bone healing. The medial open wedge osteotomy provides better control of valgisation at the proximal hip, while maintaining the alignment of the lateral cortex. We used double-angled blade plates, as they remove less bone, prevent medialisation of the distal segment, and provide rotational stability to the proximal segment.^2,3 Preserving the femoral anatomy allowed for subsequent easy placement of femoral components during hip arthroplasty in our patients. Improving the neck-shaft angle by applying pre-operative traction also reduces the degree of deformity correction.

Our series had no cases of nonunion, despite creating an open wedge medially. All osteotomies and neck fractures healed. Based on experience and reports, we did not aim for excessive valgus correction, as overcorrection or excessive valgus can result in AVN of the femoral heads due to increased joint reaction forces. ³ Adequate correction to match the contralateral neck shaft angle should suffice, and even with an under-correction, the healing rate is as high as 97%. ¹⁵ There is a natural lateralisation of the distal segment as the wedge is opened, making the conversion to THA less complex. It is important to note that in our series, the 3 patients who subsequently developed AVN were those who had experienced failed fixation of their femoral neck fractures, with head penetration likely contributing to the AVN. (Supplemental Figures 1–3).

THR after proximal femur osteotomies can be challenging.^4,16 Compared to primary arthroplasty for hip osteoarthritis, the results are less predictable, with higher complication rates following THR for failed femoral neck fractures.^17,18 If the anatomy of the proximal femur is altered, as in intertrochanteric and subtrochanteric valgus osteotomies, it can increase intraoperative complications such as perforations. ¹⁹ Additionally, these procedures are associated with a higher incidence of complications, including femoral fractures, nerve palsies and dislocation. ¹⁶

The limitations of this study include the relatively rare condition of neck of femur nonunions, a small sample size, a lack of comparative data, and the technical skills required to perform both the lateral closing wedge intertrochanteric osteotomy and our novel medial opening wedge osteotomy. This osteotomy may also be ineffective for childhood deformities such as post-dysplasia, as the entire proximal femur anatomy is altered by deformities in all planes, especially when more extensive corrections are needed. Correcting a dysplastic hip with deformity in the femoral neck (transcervical or subcapital) is challenging. In cases of large angular corrections, authors have noted the practice of leaving the blade plate less seated in the proximal fragment to facilitate alignment of the shaft with the anatomical axis. ²⁰

In conclusion, the medial open wedge valgus intertrochanteric osteotomy has a high union rate for both the fracture neck nonunion and the osteotomy performed. It preserves the proximal femoral anatomy, facilitating subsequent conversion to a less complex THA.

Supplemental Material

Supplemental Material

Supplemental Material