Corrective osteotomies of the radius: Grafting or not?

Abstract

AIM: To review the current literature regarding corrective osteotomies to provide the best evidence of the rule of bone grafting.

METHODS: Our MEDLINE literature search included 280 studies using the following key words “Malunited distal radius fracture” and 150 studies using key words “Corrective osteotomy of the distal radius”. Inclusion criteria were: Malunited distal radial, extra articular fracture, volar locking plate, use of iliac bone graft (cancellous or corticocancellous), non-use of bone graft. Twelve studies met the inclusion criteria.

RESULTS: Seven of the 12 studies considered, described the use of a graft; the remaining five studies didn’t use any graft. Type of malunion was dorsal in most of the studies. The healing time was comparable using the graft or not (mean 12.5 wk), ranging from 7.5 to 16 wk. The mean disabilities of the arm, shoulder and hand score improvement was 23 points both in the studies that used the graft and in those not using the graft.

CONCLUSION: This review demonstrated that corrective osteotomy of extra-articular malunited fractures of the distal radius treated by volar locking plate does not necessarily require bone graft.

Key Words: Radial fracture; Osteotomy; Graft; Volar plate; Malunion

Core tip: The aim of this study was to review the current literature regarding corrective osteotomies in malunion of the distal radius to provide the best evidence of the rule of bone graft. The results of this review demonstrated that corrective osteotomy of extra-articular malunited fractures of the distal radius treated by volar locking plate does not necessarily require bone graft. Rate of union and functional outcomes were comparable.

INTRODUCTION

Distal radius fractures represent the 10%-12% of all fractures[1-3]. One of the most common complication following distal radial fractures is malunion, especially when treated with close reduction and cast immobilization[4]. Patients with symptomatic malunions of the distal radius usually present with wrist pain; restricted wrist range of motion (ROM), especially supination; reduced grip strength; unsightly appearance; late neuropathy especially of the median nerve, with compression at the carpal tunnel[5-7]. Corrective osteotomy aims to restore anatomic configuration and improve function in unsatisfied patients.

Over the last few years, various corrective osteotomy techniques have been characterized[1,6,8]. Although opening wedge osteotomy through a dorsal approach, using bone graft and non-locking plates has been in the past years the most widely recommended technique for treating distal radius malunion, this procedure requires an extensive dorsal approach and often determines extensor tendons irritation. Recently, with the introduction of fixed-angle plates, interest in performing these osteotomies through a volar approach has increased[9,10]. According to the opening wedge treatment of a fracture united in a position of abnormality or deformity, a 3-D structural defect is produced by the surgeon in the distal radial metaphysis. The defect will then be filled with 3 different approaches: bone grafting, using a structural o non-structural autogenous corticocancellous bone graft; synthetic material [Norian, bone morphogenic proteins (BMP), osteogenic protein-1 (OP-1)]; no bone graft[11,12].

Bone graft

Corticocancellous bone can be derived from the iliac crest, distal femur, proximal tibia, fibula, distal radius and olecranon. Generally, the most used kind of bone graft is the autograft. Defects of a length smaller than 5 to 6 cm are well managed by nonvascularized iliac crest bone grafts, if in presence of well-perfused soft tissues and in absence of any active infection. Therefore they usually represent the first choice treatment of the defect created by the osteotomy. Bone graft helps to maintain the surgical corrections but with possible donor site morbidity: Persistent and chronic pain, serious discharge, nerve injury with meralgia, paresthesia, infection, fractures, pelvic instability, hematoma, cosmetic defects, hernia, ureteral injuries, arterial injuries[12]. Moreover, sometimes it is not always feasible to shape a structural bone graft based on the dimensions of the defect precisely[13]. Studies have demonstrated that osteotomies filled with cancellous or corticocancellous grafts give comparable results[14]. Anyway, cancellous is recognised to have three advantages over corticocancellous graft: first, it has no need for a specific anatomic configuration, since it can be totally compressed to stuff the defect, it gives the possibility to bypass the long procedure to prepare a structural graft, and lastly, it is not that difficult to applicate plate and screws (no displacement during the fixation) (Figures 1 and 2).

Figure 1 Preoperative X-rays and 3D-computed tomography evaluation showing an extra-articular dorsal malunion in a 36 years old man.

Figure 2 Intraoperative view and post-operative X-rays of the surgical procedure using a volar locking plate and cancellous bone graft.

Synthetic graft

Autologous bone grafts can be replaced by bone substitute to elude donor site morbidity. Hydroxyapatite (HA) and calcium-sulphate (CS) are mineral-based substitutes for osteoconductive bone grafts. Osteotomies of malunited distal radial fractures[15] and surgery of distal radial fractures[16] has seen the use of HA as a substitute. Even tough the time lapse of resorbing graft is of years, it should have the strength necessary to absorb stress until the bone has formed. Although CS has been shown to be highly biocompatible, the resorption rate it is too rapid to be used in fracture treatment. Indeed the CS resorption is faster than the new bone formation; potentially causing hardware failure that can be avoided by maintaining a cortical contact across the osteotomy site[16,17].

Osteoconductive bone graft substitutes

Extensive research has been conducted on osteoconductive alternatives, associated with growth factors and proteins such as BMPs. Mesenchymal stem cells have been seen to differentiate into chondrocytes and osteoblasts driven by the primitive induction of the BMPs, which are members of the transforming growth factor-β. Preclinical effectiveness investigation on BMPs took to subsequent clinical introduction of the most powerful BMPs, BMP-2 and BMP-7[18,19]. OP-1, which also goes under the name of recombinant BMP-7, has been known for its osteoinductive properties. Animal and clinical trials showed therapeutic potential in more than a study. Demonstration of the efficacy of this grafts has been documented in spinal fusion, fibular defects, tibial non-union, and most recently also in pelvic girdle non-union[19,20]. According to Ekrol et al[20], OP-1 substitute has been shown not to elicit the same stability and stress absorption as bone graft across the osteotomy site; furthermore using the combination of a plate with OP-1 resulted in healing of the osteotomy but with a slower rate than autogenous bone graft.

No bone graft

Bone graft seems to be not always necessary when the distal malunion is extra articular and it’s treated with a locking plate: The absence of bone graft seems not to adversely affect time to union and functional outcome.

In this case correction should be achieved in the coronal and sagittal planes by having the distal radius conform to the tilt of the plate. It can be useful to maintain a volar cortical contact following corrective osteotomy, to ensure the physiological transmission of the force vector through the synthesis, from the distal to the proximal segment of the radius[21] (Figures 3-5).

Figure 3 Preoperative X-rays showing an extra-articular dorsal malunion in a 51 years old man.

Figure 4 Intraoperative X-rays showing corrective osteotomy of extra-articular dorsally displaced malunion of the distal radius treated by volar locking plate without bone graft, and maintaining volar cortical contact.

Figure 5 X-rays performed 3 mo post-operatively showing the healing process in progress.

MATERIALS AND METHODS

Our MEDLINE literature search included 280 studies using the following key words “Malunited distal radius fracture” and 150 studies using key words “Corrective osteotomy of the distal radius”. Inclusion criteria were: Malunited distal radial, extra articular fracture, volar locking plate, use of iliac bone graft (cancellous or corticocancellous), non use of bone graft. Twelve studies met the inclusion criteria. Although important, time of healing and clinical outcome, were not reported in all the studies included in the review.

RESULTS

For each study the number of evaluated patients, surgical technique (graft or not), number of patients enrolled, type of malunion, time of healing and functional recovery regarded as disabilities of the arm, shoulder and hand (DASH) score, pain improvement [visual analogue scale (VAS) and any eventual post-surgical complication (Table 1) were reported. In 7 out of the 12 studies included the graft was used: Iliac crest corticocancellous bone graft in 4 studies and iliac crest cancellous bone graft in 3. Moreover Malone et al[22] used crushed cancellous allograft in 1 case and Wada et al[23] tricalcium phosphate. In the remaining five studies grafting was not described. Despite this, the number of patients of all studies treated with graft was inferior to the number of those treated without graft (97 vs 104). Type of malunion was dorsal in most of the studies. The healing time was comparable using the graft or not (mean 12.5 wk), ranging from 7.5[24] to 16[25,26] wk. The mean DASH score improvement was 23 points both in the studies describing the use of the graft (range, 11-46)[22-24,27-29], and in those not using the graft (range, 13-28)[25,30-32]. Finally, few studies reported postoperative complications[11,22,23,26,29,32]. Among the majority of the studies neither complications nor significative correction loss were indicated after surgery, even in elderly people. The results of the main evaluated literature are summarized in Table 1.

Table 1 Results of the main evaluated literature.

Ref.	No. of patients	Graft	Type of malunion	Time to healing	Clinical outcome (DASH)	Pain (VAS)	Complications
Gradl et al[27]	14	ICCCBG in all cases	Dorsal in 7 cases; volar in 4 cases	Not reported	36	4.2 ± 2.9	None
Malone et al[22]	3	ICCCBG in 2 cases; CCA in 1 case	Dorsal in all cases	9 wk	12	3.3	1 post-traumatic fracture
Peterson et al[28]	8	ICCCBG in all cases	Dorsal in 6 cases; volar in 2 cases	Not reported	10.8	Not reported	None
Rothenfluh et al[29]	14	ICCBG in all cases	Dorsal in all cases	12 wk	17.3	3.59	Secondary dislocation of the distal fragment was observed 21 d after surgery in 1 case
Wada et al[23]	16	ICCBG or tricalcium phosphate bone substitute	Dorsal and volar	13 wk	14	Significant improvement	2 delayed unions
Sato et al[24]	28	ICCCBG in all cases	Volar in all cases	7.5 wk	46	4.2	None
Miyake et al[26]	10	ICCBG in all cases	Dorsal in all cases	16 wk	Not reported	Significant improvement	Early postoperative screw loosening in 2 cases
Farshad et al[11]	28	None	Not specified	Not reported	Not reported	Not reported	Plate bending in 6 cases
Mahmoud et al[32]	22	None	Dorsal in all cases	10.4 wk	21.6 ± 13.5	3.4 ± 1.5	Intraoperative split in the shaft of the radius in 1 case
							CRPS in 1 case
							Residual pain in 2 cases
Opel et al[30]	20	None	Not specified	12 wk	13.4	Not reported	None
Ozer et al[31]	14	None	Dorsal in all cases	11 wk	28	Not reported	None
Tarallo et al[25]	20	None	Dorsal in all cases	16 wk	28.5	0.8	None

VAS: Vidual analogue scale; DASH: Disabilities of the arm, shoulder and hand; ICCCBG: Iliac crest cortico cancellous bone graft; CCA: Crushed cancellous allograft; ICCBG: Iliac crest cancellous bone graft; CRPS: Complex regional pain syndrome.

DISCUSSION

The majority of the examined literature used the bone graft to fix the remaining defect with corticocancellous or cancellous autogenous bone from the iliac crest. Gradl et al[27] employed iliac crest corticocancellous bone graft in all case of malunion. He included in his study 18 patients treated using a palmar approach in 14 cases and a combined approach (palmar + dorsal) in 4 cases. There were 7 palmar and 11 dorsal malunions, and remaining defects were fixed with corticocancellous autogenous bone graft from the iliac crest in 14 patients, and cancellous bone graft from the radius in one patient. At a mean 7 years of follow-up wrist ROM improved significantly in all cases and the DASH score decreased significantly from 59 to 23 points.

Treatment with transverse opening wedge osteotomy with oblique iliac bone graft of volarly malunited distal radius fractures led to a significative improvement in DASH score as reported by Sato et al[24] in 2009. All patients were analyzed at a mean 25 mo of follow-up. Mean preoperative VAS scale was 45, improving significantly to 3 postoperatively. Range of wrist motion improved in all 28 patients, with supination range improving from 16° preoperatively to 80° postoperatively. Mean DASH score improvement from 55 to 9 postoperatively. X-rays evaluation showed an improvement of the volar tilt from 32° preoperatively to 10° postoperatively, and radial inclination increased from 17° to 21°. Preoperative ulnar variance of 5.9 mm was corrected to -0.1 mm postoperatively. Fifty-two days was the average time for bony union at osteotomy site (young patients, 51 d; older patients, 54 d).

Many authors described complications following the surgical treatment of dorsal malunion: Extensor tenosynovitis and, sometimes, tendon ruptures connected with the use of dorsal plates[20,33,34]. Keller et al[35] evaluated a series of 49 cases that underwent dorsal plating of the distal radius, reporting, at 32 mo follow-up, an average DASH score of 14.4 with good motion and grip strength. To be noted that 37 of the 49 patients required plate removal and of the 12 patients who did not undergo plate removal, one patient suffered a rupture of the extensor indicis proprius. It’s common opinion among the authors that extensor tendon complications are the result of the profile of the dorsal plate[21,27], but more recent studies claim that this complication can occur even with low-profile plates. Moreover screw placement is important: Gradl et al[27] reported in one case the development of symptomatic tendinitis of the extensor pollicis longus tendon due to dorsal protrusion of screw tips after corrective osteotomy with a palmar locking plate and autogenous bone grafting. Malone et al[22] emphasized the role of the volar plate including structural bone grafting: Four corrective osteotomies has been performed using the volar approach for dorsally angulated malunion of distal radius fracture with a volar plate; two patients received autologous iliac crest bone graft, 1 patient received crushed cancellous allograft, and 1 patient had a distal ulna resection for ulnar impaction symptoms and the distal ulna was used as a source for the bone graft. The authors came to the concept that the stiff characteristics of fixed angle volar plates could provide an alternative to the traditional techniques of distal radius osteotomy including structural bone grafting and dorsal plate fixation or external fixation. Comparable results in terms of anatomic restoration of the distal radius, ROM improvement in the radiocarpal joint, and restoration of the anatomic relationships of the distal radioulnar join were obtained by Rothenfluh et al[29], Wada et al[23], and Peterson et al[28]. All these authors used bone graft from the iliac crest with a comparable DASH scores and no complications. Only Rothenfluh et al[29] reported in one case a secondary dislocation of the distal fragment observed 21 d after volar osteotomy. In his study Rothenfluh et al[29] compared the results of dorsal approach plus structural trapezoidal bone graft stabilized using a thin round-hole mini-fragment plate, with palmar approach plus nonstructural cancellous bone chips and a palmar fixed-angle plate, suggesting comparable results to those achieved with dorsal osteotomy and the interposition of cortico-cancellous bone graft. However, the palmar approach determined a more favorable effect on wrist flexion, entailing lower complication rates, mainly represented by extensor tendonitis and hardware removal.

Several articles treated corrective osteotomy without bone graft and the first reports concerning this topic dates back to 1930s[36]. In recent literature, Mahmoud et al[32] described the results of 22 corrective osteotomies of extra-articular dorsally-angulated malunited fractures of the distal radius fixed by a volar locked plate without the use of bone graft. Radiological healing was achieved in all patients at a mean of 10.4 wk (8 to 14). At a mean of 18 (12 to 25) mo of follow-up the DASH score improved from 34.5 points to 12.9; improvements in the VAS score and grip strength were respectively 3.4 points and 17.4 kg; radiological correction of the deformity and ROM improvement were achieved in all cases. Complications occurred in six cases (27%): an intraoperative longitudinal split occurred in the shaft of the radius in one patient, requiring an interfragmentary compression screw; one patient suffered a transient median nerve neuritis; another patient suffered from CRPS, which was healed by physiotherapy; a prominent screw determined tendon impingement and required removal; residual pain on the ulnar side of the wrist due to ulnar impaction was encountered in two patients, requiring ulnar shortening. Tarallo et al[25] treated 20 patients for symptomatic dorsally malunited extra-articular fractures of the distal radius with osteotomy and a volar locking plate without additional bone graft. The authors reported, at a mean 50 mo of follow-up, a significant improvement in pain level, ROM, grip strength, and DASH score.

An important factor to consider is that bone healing is determined by several factors, including cell differentiation, compromise of vascularity, and mechanical stability[37]. Sheer et al[37], in a recent study, concluded that although there are few data on metaphyseal bone healing, there are some indications that it adheres to the same biomechanical principles as diaphyseal bone healing, with some differences concerning bone formation, which may follow different paths. The cortical contact between the osteotomy fragments represents an important factor, too. Ozer et al[31], investigated this aspect underlining the importance to maintain a volar cortical contact following the placement of the volar locking plate in order to obtain a better outcome, especially in extra-articular malunited fractures of the distal radius. They state that in such cases, it would not be necessarily required the use of bone graft.

The use of autogenous bone grafts has been reported to have high complication rates, with associated morbidity of up to 73%, and an additional operative time averaging 20 min[31]. The most important complication reported by several authors is donor site morbidity, especially at the iliac crest. Minor complications, occurring in 7.1%-39% of patients, include persistent pain at the harvest site, sensory nerve injury, hematoma or seroma, and superficial infection[38,39]. Concerning the use of a synthetic material, such products come with an inherent advantage of no donor site morbidity; however their use also come with a high cost of production and sometimes a potentially low, but real, risk of disease transmission. Abramo et al[18] evaluated 25 consecutive patients with a dorsal malunion after a distal radius fracture treated with corrective osteotomy using a dorsal approach. A TriMed buttress pin and a radial pin plate were used, and calcium phosphate mixture (Norian SRS) as bone substitute. At a 1-year follow-up grip strength increased from 62% of the contralateral hand to 82%, with a DASH score improvement of 12 points. Minor complications involving transient tingling and numbness from the radial nerve branches were reported initially in 6 cases, but disappeared by the last follow-up. One major complication occurred: The bone substitute fragmented before osseous union and the plate and screws broke 2 mo postoperatively. The patient was re-operated using conventional bone grafting and fixation with a dorsal AO plate.

Jepegnanam et al[40] reported on early mechanical failure of injectable calcium sulfate, leading to implant failure in 2 elderly patients who had corrective osteotomies for malunited distal radius fractures. Faster resorption might have specific advantages under certain conditions but might also be disadvantageous if it is required to contribute to mechanical support for many weeks or months. The authors hypothesized that the failures occurred because new bone formation did not occur rapidly enough to replace resorption of the grafted material.

Jepegnanam et al[40], suggest that graft substitutes with a faster resorption rate should be used with caution in patients with expected slow bone healing. The major stability of bone graft compared with synthetic material is also emphasized by Ekrol et al[20]. They compared the OP-1 and autogenous graft for metaphyseal defects after osteotomy of the distal radius, concluding that OP-1 does not confer the same stability as bone graft, reducing the capacity for healing and resulting in osteolysis.

Conclusion

The results of this review demonstrate that corrective osteotomy of extra-articular malunited distal radius fractures treated by volar locking plate does not necessarily require the use of bone graft. Rate of union and functional outcomes are comparable to the use of bone graft. We suggest maintaining a volar cortical contact following corrective osteotomy, to ensure the physiological transmission of the force vector through the synthesis, from the distal segment of the radio to the proximal one.

Bone grafts however, remain a valuable support in this type of surgery, especially to fill gaps when a large defect is created. Synthetic materials come with an inherent advantage of no donor site morbidity but it seems that they do not confer the same stability as bone graft. Their use is limited by faster resorption rate than bone graft, so they should be used with caution in patients with expected slow bone healing rate.

COMMENTS

Background

Different techniques for corrective osteotomy have been described in recent years; although opening wedge osteotomy through a dorsal approach, using bone graft and non-locking plates has been in the past years the most widely recommended technique for treating distal radius malunion, this procedure requires an extensive dorsal approach and often determines extensor tendons irritation. Recently, with the introduction of fixed-angle plates, interest in performing these osteotomies through a volar approach has increased.

Research frontiers

According to the opening wedge treatment of a malunited fracture, the surgeon creates a 3-dimensional structural defect in the distal radial metaphysis, which will be filled with 3 different approaches: Bone grafting, using a structural o non-structural autogenous corticocancellous bone graft; synthetic material (Norian, bone morphogenic proteins, osteogenic protein-1); no bone graft.

Innovations and breakthroughs

Current publication is the first systematic review, which summarize published data concerning the use of bone graft in corrective osteotomy of extra-articular malunited fractures of the distal radius treated by volar locking plate. The results of this review demonstrate that corrective osteotomy of extra-articular malunited fractures of the distal radius treated by volar locking plate does not necessarily require the use of bone graft. Rate of union and functional outcomes are comparable to the use of bone graft. However bone graft still represents a valuable solution in this type of surgery, especially to fill the gap when a large osteotomy is performed.

Applications

Given similar rates of union, functional outcomes and complications occurrence, the authors suggest that when a volar cortical contact is maintained following corrective osteotomy the use of bone graft is not necessarily required.

Terminology

Cancellous bone is the meshwork of spongy tissue (trabeculae) of mature adult bone. The most common harvesting site for autogenous cancellous bone graft is the iliac crest, tibial crest, humeral greater tubercle and greater trochanter of femur. Cancellous bone autograft offers the considerable amounts of viable cells that boost the osteogenesis, matrix protein that promotes the osteoinduction and bone matrix that encourage the osteoinduction. Cancellous bone grafts lack biomechanical strength and do not supply structural support. Corticocancellous grafts yield significant mechanical strength and can be used to either replace bone losses or to augment the mechanical stability of the fixation. The most common sites for harvesting corticocancellous bone autograft are ribs, the anterosuperior iliac crest and the posterior iliac crest.

Peer-review

This is a good study.