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The Journal of Bone & Joint Surgery British Volume
Vol. 93-B, Issue 5 | Pages 580 - 586
1 May 2011
Hartofilakidis G Bardakos NV Babis GC Georgiades G

We retrospectively examined the long-term outcome of 96 asymptomatic hips in 96 patients with a mean age of 49.3 years (16 to 65) who had radiological evidence of femoroacetabular impingement. When surveillance commenced there were 17, 34, and 45 hips with cam, pincer, and mixed impingement, respectively. Overall, 79 hips (82.3%) remained free of osteoarthritis for a mean of 18.5 years (10 to 40). In contrast, 17 hips (17.7%) developed osteoarthritis at a mean of 12 years (2 to 28). No statistically significant difference was found in the rates of development of osteoarthritis among the three groups (p = 0.43). Regression analysis showed that only the presence of idiopathic osteoarthritis of the contralateral diseased hip was predictive of development of osteoarthritis on the asymptomatic side (p = 0.039).

We conclude that a substantial proportion of hips with femoroacetabular impingement may not develop osteoarthritis in the long-term. Accordingly, in the absence of symptoms, prophylactic surgical treatment is not warranted.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 11 | Pages 1540 - 1545
1 Nov 2012
Reigstad O Lütken T Grimsgaard C Bolstad B Thorkildsen R Røkkum M

The Motec cementless modular metal-on-metal ball-and-socket wrist arthroplasty was implanted in 16 wrists with scaphoid nonunion advanced collapse (SNAC; grades 3 or 4) and 14 wrists with scapholunate advanced collapse (SLAC) in 30 patients (20 men) with severe (grades 3 or 4) post-traumatic osteoarthritis of the wrist. The mean age of the patients was 52 years (31 to 71). All prostheses integrated well radiologically. At a mean follow-up of 3.2 years (1.1 to 6.1) no luxation or implant breakage occurred. Two wrists were converted to an arthrodesis for persistent pain. Loosening occurred in one further wrist at five years post-operatively. The remainder demonstrated close bone–implant contact. The clinical results were good, with markedly decreased Disabilities of the Arm Shoulder and Hand (DASH) and pain scores, and increased movement and grip strength. No patient used analgesics and most had returned to work.

Good short-term function was achieved using this wrist arthroplasty in a high-demand group of patients with post-traumatic osteoarthritis.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 12 | Pages 1690 - 1694
1 Dec 2010
Scoccianti G Campanacci DA Beltrami G Caldora P Capanna R

Several techniques have been described to reconstruct a mobile wrist joint after resection of the distal radius for tumour. We reviewed our experience of using an osteo-articular allograft to do this in 17 patients with a mean follow-up of 58.9 months (28 to 119).

The mean range of movement at the wrist was 56° flexion, 58° extension, 84° supination and 80° pronation. The mean ISOLS-MSTS score was 86% (63% to 97%) and the mean patient-rated wrist evaluation score was 16.5 (3 to 34). There was no local recurrence or distant metastases. The procedure failed in one patient with a fracture of the graft and an arthrodesis was finally required. Union was achieved at the host-graft interface in all except two cases. No patient reported more than modest non-disabling pain and six reported no pain at all. Radiographs showed early degenerative changes at the radiocarpal joint in every patient.

A functional pain-free wrist can be restored with an osteo-articular allograft after resection of the distal radius for bone tumour, thereby avoiding the donor site morbidity associated with an autograft. These results may deteriorate with time.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 12 | Pages 1611 - 1617
1 Dec 2012
Jameson SS Baker PN Mason J Gregg PJ Brewster N Deehan DJ Reed MR

Despite excellent results, the use of cemented total hip replacement (THR) is declining. This retrospective cohort study records survival time to revision following primary cemented THR using the most common combination of components that accounted for almost a quarter of all cemented THRs, exploring risk factors independently associated with failure. All patients with osteoarthritis who had an Exeter V40/Contemporary THR (Stryker) implanted before 31 December 2010 and recorded in the National Joint Registry for England and Wales were included in the analysis. Cox’s proportional hazard models were used to analyse the extent to which risk of revision was related to patient, surgeon and implant covariates, with a significance threshold of p < 0.01. A total of 34 721 THRs were included in the study. The overall seven-year rate of revision for any reason was 1.70% (99% confidence interval (CI) 1.28 to 2.12). In the final adjusted model the risk of revision was significantly higher in THRs with the Contemporary hooded component (hazard ratio (HR) 1.88, p < 0.001) than with the flanged version, and in smaller head sizes (< 28 mm) compared with 28 mm diameter heads (HR 1.50, p = 0.005). The seven-year revision rate was 1.16% (99% CI 0.69 to 1.63) with a 28 mm diameter head and flanged component. The overall risk of revision was independent of age, gender, American Society of Anesthesiologists grade, body mass index, surgeon volume, surgical approach, brand of cement/presence of antibiotic, femoral head material (stainless steel/alumina) and stem taper size/offset. However, the risk of revision for dislocation was significantly higher with a ‘plus’ offset head (HR 2.05, p = 0.003) and a hooded acetabular component (HR 2.34, p < 0.001).

In summary, we found that there were significant differences in failure between different designs of acetabular component and sizes of femoral head after adjustment for a range of covariates.


The Journal of Bone & Joint Surgery British Volume
Vol. 89-B, Issue 11 | Pages 1482 - 1487
1 Nov 2007
Gupta A

We describe a series of 20 patients with ununited fractures of the femoral neck following neglected trauma or failed primary internal fixation who were seen at a mean of 7.5 months (2 to 18) following injury. Open reduction and internal fixation of the fracture was performed in all patients, together with a myoperiosteal flap on the quadratus femoris muscle pedicle.

Union occurred at a mean of 4.9 months (2 to 10) in all patients. The mean follow-up was for 70 months (14 to 144). There was no further progression in six of seven patients with pre-operative radiological evidence of osteonecrosis of the femoral head. One patient had delayed collapse and flattening of the femoral head ten years after union of the fracture, but remained asymptomatic.

This study demonstrates the orthopaedic application of myoperiosteal grafting for inducing osteogenesis in a difficult clinical situation.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 10 | Pages 1403 - 1408
1 Oct 2012
Hannemann PFW Göttgens KWA van Wely BJ Kolkman KA Werre AJ Poeze M Brink PRG

The use of pulsed electromagnetic fields (PEMF) to stimulate bone growth has been recommended as an alternative to the surgical treatment of ununited scaphoid fractures, but has never been examined in acute fractures. We hypothesised that the use of PEMF in acute scaphoid fractures would accelerate the time to union by 30% in a randomised, double-blind, placebo-controlled, multicentre trial. A total of 53 patients in three different medical centres with a unilateral undisplaced acute scaphoid fracture were randomly assigned to receive either treatment with PEMF (n = 24) or a placebo (n = 29). The clinical and radiological outcomes were assessed at four, six, nine, 12, 24 and 52 weeks.

A log-rank analysis showed that neither time to clinical and radiological union nor the functional outcome differed significantly between the groups. The clinical assessment of union indicated that at six weeks tenderness in the anatomic snuffbox (p = 0.03) as well as tenderness on longitudinal compression of the scaphoid (p = 0.008) differed significantly in favour of the placebo group.

We conclude that stimulation of bone growth by PEMF has no additional value in the conservative treatment of acute scaphoid fractures.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 1 | Pages 28 - 37
1 Jan 2010
Jameson SS Langton DJ Nargol AVF

We present the early clinical and radiological results of Articular Surface Replacement (ASR) resurfacings in 214 hips (192 patients) with a mean follow-up of 43 months (30 to 57). The mean age of the patients was 56 years (28 to 74) and 85 hips (40%) were in 78 women.

The mean Harris hip score improved from 52 (11 to 81) to 95 (27 to 100) at two years and the mean University of California, Los Angeles activity score from 3.9 (1 to 10) to 7.4 (2 to 10) in the same period. Narrowing of the neck (to a maximum of 9%) was noted in 124 of 209 hips (60%). There were 12 revisions (5.6%) involving four (1.9%) early fractures of the femoral neck and two (0.9%) episodes of collapse of the femoral head secondary to avascular necrosis. Six patients (2.8%) had failure related to metal wear debris. The overall survival for our series was 93% (95% confidence interval 80 to 98) and 89% (95% confidence interval 82 to 96) for hips with acetabular components smaller than 56 mm in diameter.

The ASR implant has a lower diametrical clearance and a subhemispherical acetabular component when compared with other more frequently implanted metal-on-metal hip resurfacings. These changes may contribute to the higher failure rate than in other series, compared with other designs. Given our poor results with the small components we are no longer implanting the smaller size.


The Journal of Bone & Joint Surgery British Volume
Vol. 93-B, Issue 1 | Pages 102 - 107
1 Jan 2011
Di Mascio L Chin K Fox M Sinisi M

We describe the early results of glenoplasty as part of the technique of operative reduction of posterior dislocation of the shoulder in 29 children with obstetric brachial plexus palsy. The mean age at operation was five years (1 to 18) and they were followed up for a mean of 34 months (12 to 67).

The mean Mallet score increased from 8 (5 to 13) to 12 (8 to 15) at final follow-up (p < 0.001). The mean passive forward flexion was increased by 18° (p = 0.017) and the mean passive abduction by 24° (p = 0.001). The mean passive lateral rotation also increased by 54° (p < 0.001), but passive medial rotation was reduced by a mean of only 7°. One patient required two further operations. Glenohumeral stability was achieved in all cases.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 11 | Pages 1509 - 1514
1 Nov 2010
Smolders JMH Hol A Rijnders T van Susante JLC

We undertook a randomised prospective follow-up study of changes in peri-prosthetic bone mineral density (BMD) after hip resurfacing and compared them with the results after total hip replacement. A total of 59 patients were allocated to receive a hip resurfacing (n = 29) or an uncemented distally fixed total hip replacement (n = 30). The BMD was prospectively determined in four separate regions of interest of the femoral neck and in the calcar region corresponding to Gruen zone 7 for the hip resurfacing group and compared only to the calcar region in the total hip replacement group. Standardised measurements were performed pre-operatively and after three, six and 12 months. The groups were well matched in terms of gender distribution and mean age.

The mean BMD in the calcar region increased after one year to 105.2% of baseline levels in the resurfaced group compared with a significant decrease to 82.1% in the total hip replacement group (p < 0.001) by 12 months. For the resurfaced group, there was a decrease in bone density in all four regions of the femoral neck at three months which did not reach statistical significance and was followed by recovery to baseline levels after 12 months.

Hip resurfacing did indeed preserve BMD in the inferior femoral neck. In contrast, a decrease in the mean BMD in Gruen zone 7 followed uncemented distally fixed total hip replacement. Long term follow-up studies are necessary to see whether this benefit in preservation of BMD will be clinically relevant at future revision surgery.


The Journal of Bone & Joint Surgery British Volume
Vol. 91-B, Issue 6 | Pages 713 - 719
1 Jun 2009
Denaro V Papalia R Denaro L Di Martino A Maffulli N

Cervical spinal disc replacement is used in the management of degenerative cervical disc disease in an attempt to preserve cervical spinal movement and to prevent adjacent disc overload and subsequent degeneration. A large number of patients have undergone cervical spinal disc replacement, but the effectiveness of these implants is still uncertain. In most instances, degenerative change at adjacent levels represents the physiological progression of the natural history of the arthritic disc, and is unrelated to the surgeon. Complications of cervical disc replacement include loss of movement from periprosthetic ankylosis and ossification, neurological deficit, loosening and failure of the device, and worsening of any cervical kyphosis. Strict selection criteria and adherence to scientific evidence are necessary. Only prospective, randomised clinical trials with long-term follow-up will establish any real advantage of cervical spinal disc replacement over fusion.


The Journal of Bone & Joint Surgery British Volume
Vol. 89-B, Issue 2 | Pages 169 - 173
1 Feb 2007
Daniel J Ziaee H Pradhan C Pynsent PB McMinn DJW

This is a longitudinal study of the daily urinary output and the concentrations in whole blood of cobalt and chromium in patients with metal-on-metal resurfacings over a period of four years.

Twelve-hour urine collections and whole blood specimens were collected before and periodically after a Birmingham hip resurfacing in 26 patients. All ion analyses were carried out using a high-resolution inductively-coupled plasma mass spectrometer. Clinical and radiological assessment, hip function scoring and activity level assessment revealed excellent hip function.

There was a significant early increase in urinary metal output, reaching a peak at six months for cobalt and one year for chromium post-operatively. There was thereafter a steady decrease in the median urinary output of cobalt over the following three years, although the differences are not statistically significant. The mean whole blood levels of cobalt and chromium also showed a significant increase between the pre-operative and one-year post-operative periods. The blood levels then decreased to a lower level at four years, compared with the one-year levels. This late reduction was statistically significant for chromium but not for cobalt.

The effects of systemic metal ion exposure in patients with metal-on-metal resurfacing arthroplasties continue to be a matter of concern. The levels in this study provide a baseline against which the in vivo wear performance of newer bearings can be compared.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 9 | Pages 1180 - 1186
1 Sep 2012
Murray DW Grammatopoulos G Pandit H Gundle R Gill HS McLardy-Smith P

Recent events have highlighted the importance of implant design for survival and wear-related complications following metal-on-metal hip resurfacing arthroplasty. The mid-term survival of the most widely used implant, the Birmingham Hip Resurfacing (BHR), has been described by its designers. The aim of this study was to report the ten-year survival and patient-reported functional outcome of the BHR from an independent centre.

In this cohort of 554 patients (646 BHRs) with a mean age of 51.9 years (16.5 to 81.5) followed for a mean of eight years (1 to 12), the survival and patient-reported functional outcome depended on gender and the size of the implant. In female hips (n = 267) the ten-year survival was 74% (95% confidence interval (CI) 83 to 91), the ten-year revision rate for pseudotumour was 7%, the mean Oxford hip score (OHS) was 43 (sd 8) and the mean UCLA activity score was 6.4 (sd 2). In male hips (n = 379) the ten-year survival was 95% (95% CI 92.0 to 97.4), the ten-year revision rate for pseudotumour was 1.7%, the mean OHS was 45 (sd 6) and the mean UCLA score was 7.6 (sd 2). In the most demanding subgroup, comprising male patients aged < 50 years treated for primary osteoarthritis, the survival was 99% (95% CI 97 to 100).

This study supports the ongoing use of resurfacing in young active men, who are a subgroup of patients who tend to have problems with conventional THR. In contrast, the results in women have been poor and we do not recommend metal-on-metal resurfacing in women. Continuous follow-up is recommended because of the increasing incidence of pseudotumour with the passage of time.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 9 | Pages 1231 - 1237
1 Sep 2010
Santori FS Santori N

Bone preservation and physiological distribution of forces on the proximal femur are key elements in introducing a successful uncemented total hip replacement. In order to achieve this, in the mid 1990s, we developed an ultra short proximal loading custom-made component with a lateral flare, a high femoral neck osteotomy and without a diaphyseal stem.

We report the outcome of 129 custom-made hydroxyapatite-coated uncemented short femoral components inserted into 109 patients between June 1995 and May 2004. The mean age of the patients was 51 years (21 to 71) and the mean follow-up was eight years (4.9 to 14.1). Bone behaviour around the implant was studied on the post-operative radiographs. The mean Harris hip score improved from 44 (8 to 66) pre-operatively to 95 (76 to 100) at final follow-up. The Western Ontario MacMaster University Osteoarthritis index was 93 of 100 at final review. None of the patients reported thigh pain. A total of five hips were revised, three for polyethylene liner exchange and two for complete revision of the acetabular component. No femoral components were revised. The radiological changes in the proximal femur were generally good, as evidenced by spot welds both on the medial and lateral aspects of the femur. No component migrated. The presence of a lateral flare and use of a high osteotomy of the femoral neck provided good clinical and radiological results. The absence of a diaphyseal portion of the stem did not impair stability.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 5 | Pages 663 - 667
1 May 2012
Ortiz C Wagner E Mocoçain P Labarca G Keller A Del Buono A Maffulli N

We tested four types of surgical repair for load to failure and distraction in a bovine model of Achilles tendon repair. A total of 20 fresh bovine Achilles tendons were divided transversely 4 cm proximal to the calcaneal insertion and randomly repaired using the Dresden technique, a Krackow suture, a triple-strand Dresden technique or a modified oblique Dresden technique, all using a Fiberwire suture. Each tendon was loaded to failure. The force applied when a 5 mm gap was formed, peak load to failure, and mechanism of failure were recorded. The resistance to distraction was significantly greater for the triple technique (mean 246.1 N (205 to 309) to initial gapping) than for the Dresden (mean 180 N (152 to 208); p = 0.012) and the Krackow repairs (mean 101 N (78 to 112; p < 0.001). Peak load to failure was significantly greater for the triple-strand repair (mean 675 N (453 to 749)) than for the Dresden (mean 327.8 N (238 to 406); p < 0.001), Krackow (mean 223.6 N (210 to 252); p <  0.001) and oblique repairs (mean 437.2 N (372 to 526); p < 0.001). Failure of the tendon was the mechanism of failure for all specimens except for the tendons sutured using the Krackow technique, where the failure occurred at the knot.

The triple-strand technique significantly increased the tensile strength (p = 0.0001) and gap resistance (p = 0.01) of bovine tendon repairs, and might have advantages in human application for accelerated post-operative rehabilitation.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 10 | Pages 1422 - 1428
1 Oct 2010
van den Bekerom MPJ Hilverdink EF Sierevelt IN Reuling EMBP Schnater JM Bonke H Goslings JC van Dijk CN Raaymakers ELFB

The aim of this study was to analyse the functional outcome after a displaced intracapsular fracture of the femoral neck in active patients aged over 70 years without osteoarthritis or rheumatoid arthritis of the hip, randomised to receive either a hemiarthroplasty or a total hip replacement (THR). We studied 252 patients of whom 47 (19%) were men, with a mean age of 81.1 years (70.2 to 95.6). They were randomly allocated to be treated with either a cemented hemiarthroplasty (137 patients) or cemented THR (115 patients). At one- and five-year follow-up no differences were observed in the modified Harris hip score, revision rate of the prosthesis, local and general complications, or mortality. The intra-operative blood loss was lower in the hemiarthroplasty group (7% > 500 ml) than in the THR group (26% > 500 ml) and the duration of surgery was longer in the THR group (28% > 1.5 hours versus 12% > 1.5 hours). There were no dislocations of any bipolar hemiarthroplasty and eight dislocations of a THR during follow-up.

Because of a higher intra-operative blood loss (p < 0.001), an increased duration of the operation (p < 0.001) and a higher number of early and late dislocations (p = 0.002), we do not recommend THR as the treatment of choice in patients aged ≥ 70 years with a fracture of the femoral neck in the absence of advanced radiological osteoarthritis or rheumatoid arthritis of the hip.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 10 | Pages 1363 - 1369
1 Oct 2010
Garcia-Cimbrelo E Garcia-Rey E Cruz-Pardos A Madero R

Revision surgery of the hip was performed on 114 hips using an extensively porous-coated femoral component. Of these, 95 hips (94 patients) had a mean follow-up of 10.2 years (5 to 17). No cortical struts were used and the cortical index and the femoral cortical width were measured at different levels.

There were two revisions for aseptic loosening. Survivorship at 12 years for all causes of failure was 96.9% (95% confidence interval 93.5 to 100) in the best-case scenario. Fibrous or unstable fixation was associated with major bone defects. The cortical index (p = 0.045) and the lateral cortical thickness (p = 0.008) decreased at the proximal level over time while the medial cortex increased (p = 0.001) at the proximal and distal levels. An increase in the proximal medial cortex was found in patients with an extended transtrochanteric osteotomy (p = 0.026) and in those with components shorter than 25 cm (p = 0.008).

The use of the extensively porous-coated femoral component can provide a solution for difficult cases in revision surgery. Radiological bony ingrowth is common. Although without clinical relevance at the end of follow-up, the thickness of the medial femoral cortex often increased while that of the lateral cortex decreased. In cases in which a shorter component was used and in those undertaken using an extended trochanteric osteotomy, there was a greater increase in thickness of the femoral cortex over time.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 10 | Pages 1435 - 1441
1 Oct 2010
Bischel OE Böhm PM

Endoprosthetic reconstruction following resection of 31 tumours of the proximal femur in 30 patients was performed using a Wagner SL femoral revision stem. The mean follow-up was 25.6 months (0.6 to 130.0). Of the 28 patients with a metastasis, 27 died within a mean follow-up period of 18.1 months (0.6 to 56.3) after the operation, and the remaining patient was excluded from the study 44.4 months post-operatively when the stem was removed. The two patients with primary bone tumours were still alive at the latest follow-up of 81.0 and 130.0 months, respectively. One stem only was removed for suspected low-grade infection 44.4 months post-operatively. The worst-case survival rate with removal of the stem for any cause and/or loss to follow-up was 80.0% (95% confidence interval 44.9 to 100) at 130.0 months. The mean Karnofsky index increased from 44.2% (20% to 70%) pre-operatively to 59.7% (0% to 100%) post-operatively, and the mean Merle d’Aubigné score improved from 4.5 (0 to 15) to 12.0 (0 to 18). The mean post-operative Musculoskeletal Tumour Society score was 62.4% (3.3% to 100%).

The Wagner SL femoral revision stem offers an alternative to special tumour prostheses for the treatment of primary and secondary tumours of the proximal femur. The mid-term results are very promising, but long-term experience is necessary.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 2 | Pages 163 - 166
1 Feb 2012
Zahos K Mehendale S Ward AJ Smith EJ Nichols M

We report the use of a 15° face-changing cementless acetabular component in patients undergoing total hip replacement for osteoarthritis secondary to developmental dysplasia of the hip. The rationale behind its design and the surgical technique used for its implantation are described. It is distinctly different from a standard cementless hemispherical component as it is designed to position the bearing surface at the optimal angle of inclination, that is, < 45°, while maximising the cover of the component by host bone.


The Journal of Bone & Joint Surgery British Volume
Vol. 89-B, Issue 5 | Pages 599 - 603
1 May 2007
Robertsson O Stefánsdòttir A Lidgren L Ranstam J

Patients with osteoarthritis undergoing knee replacement have been reported to have an overall reduced mortality compared with that of the general population. This has been attributed to the selection of healthier patients for surgery. However, previous studies have had a maximum follow-up time of ten years. We have used information from the Swedish Knee Arthroplasty Register to study the mortality of a large national series of patients with total knee replacement for up to 28 years after surgery and compared their mortality with that of the normal population. In addition, for a subgroup of patients operated on between 1980 and 2002 we analysed their registered causes of death to determine if they differed from those expected.

We found a reduced overall mortality during the first 12 post-operative years after which it increased and became significantly higher than that of the general population. Age-specific analysis indicated an inverse correlation between age and mortality, where the younger the patients were, the higher their mortality. The shift at 12 years was caused by a relative over-representation of younger patients with a longer follow-up. Analysis of specific causes of death showed a higher mortality for cardiovascular, gastrointestinal and urogenital diseases. The observation that early onset of osteoarthritis of the knee which has been treated by total knee replacement is linked to an increased mortality should be a reason for increased general awareness of health problems in these patients.


The Journal of Bone & Joint Surgery British Volume
Vol. 92-B, Issue 3 | Pages 337 - 341
1 Mar 2010
Yamasaki T Yasunaga Y Ishikawa M Hamaki T Ochi M

We have investigated the effectiveness of the transplantation of bone-marrow-derived mononuclear cells (BMMNCs) with interconnected porous calcium hydroxyapatite (IP-CHA) on early bone repair for osteonecrosis of the femoral head. We studied 22 patients (30 hips) who had osteonecrosis with a minimum follow-up of one year after implantation of BMMNCs. The mean age at surgery was 41 years (18 to 64) and the mean period of follow-up was 29 months (19 to 48). In a control group, cell-free IP-CHA was implanted into a further eight patients (9 hips) with osteonecrosis of the femoral head and the outcomes were compared.

A reduction in the size of the osteonecrotic lesion was observed subsequent to hypertrophy of the bone in the transition zone in the BMMNC group. In three patients in the treatment group progression to extensive collapse was detected. In the control group subtle bone hypertrophy was observed, but severe collapse of the femoral head occurred in six of eight hips.

In this limited study the implantation of BMMNCs and IP-CHA appears to confer benefit in the repair of osteonecrosis and in the prevention of collapse.