In a rabbit model we investigated the efficacy of a silk fibroin/hydroxyapatite (SF/HA) composite on the repair of a segmental bone defect. Four types of porous SF/HA composites (SF/HA-1, SF/HA-2, SF/HA-3, SF/HA-4) with different material ratios, pore sizes, porosity and additives were implanted subcutaneously into Sprague-Dawley rats to observe biodegradation. SF/HA-3, which had characteristics more suitable for a bone substitite based on strength and resorption was selected as a scaffold and co-cultured with rabbit bone-marrow stromal cells (BMSCs). A segmental bone defect was created in the rabbit radius. The animals were randomised into group 1 (SF/HA-3 combined with BMSCs implanted into the bone defect), group 2 (SF/HA implanted alone) and group 3 (nothing implanted). They were killed at four, eight and 12 weeks for visual, radiological and histological study.

The bone defects had complete union for group 1 and partial union in group 2, 12 weeks after operation. There was no formation of new bone in group 3. We conclude that SF/HA-3 combined with BMSCs supports bone healing and offers potential as a bone-graft substitute.

Focal femoral inlay resurfacing has been developed for the treatment of full-thickness chondral defects of the knee. This technique involves implanting a defect-sized metallic or ceramic cap that is anchored to the subchondral bone through a screw or pin. The use of these experimental caps has been advocated in middle-aged patients who have failed non-operative methods or biological repair techniques and are deemed unsuitable for conventional arthroplasty because of their age. This paper outlines the implant design, surgical technique and biomechanical principles underlying their use. Outcomes following implantation in both animal and human studies are also reviewed.

Cite this article: Bone Joint J 2013;95-B:301–4.

McFarland fractures of the medial malleolus in children, also classified as Salter–Harris Type III and IV fractures, are associated with a high incidence of premature growth plate arrest. In order to identify prognostic factors for the development of complications we reviewed 20 children with a McFarland fracture that was treated surgically, at a mean follow-up of 8.9 years (3.5 to 17.4). Seven children (35%) developed premature growth arrest with angular deformity. The mean American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale for all patients was 98.3 (87 to 100) and the mean modified Weber protocol was 1.15 (0 to 5). There was a significant correlation between initial displacement (p = 0.004) and operative delay (p = 0.007) with premature growth arrest. Both risk factors act independently and additively, such that all children with both risk factors developed premature arrest whereas children with no risk factor did not. We recommend that fractures of the medial malleolus in children should be treated by anatomical reduction and screw fixation within one day of injury.

Cite this article: Bone Joint J 2013;95-B:419–23.

Stem cells are a key component of regenerative medicine strategies. Particular areas of musculoskeletal application include cartilage and bone regeneration in arthritis and trauma. There are several types of stem cell and this article will focus on the adult derived cells. The review includes current issues and future developments.

Disorders of the pisotriquetral joint are well recognised as the cause of pain on the ulnar side of the wrist. The joint is not usually examined during routine arthroscopy because it is assumed to have a separate joint cavity to the radiocarpal joint, although there is often a connection between the two.

We explored this connection during arthroscopy and in fresh-frozen cadaver wrists and found that in about half of the cases the pisotriquetral joint could be visualised through standard wrist portals. Four different types of connection were observed between the radiocarpal joint and the pisotriquetral joint. They ranged from a complete membrane separating the two, to no membrane at all, with various other types of connection in between.

We recommend that inspection of the pisotriquetral joint should be a part of the protocol for routine arthroscopy of the wrist.

The February 2013 Knee Roundup³⁶⁰ looks at: mobile-bearing TKRs; arthroscopic ACL reconstruction; the use of chondrocytes for osteochondral defects; ACL reconstruction and the return to pivoting sports; ACLs and the MOON study; the benefit of knee navigation; and trabecular metal.

Advances in hip arthroscopy have renewed interest in the ligamentum teres. Considered by many to be a developmental vestige, it is now recognised as a significant potential source of pain and mechanical symptoms arising from the hip joint. Despite improvements in imaging, arthroscopy remains the optimum method of diagnosing lesions of the ligamentum teres. Several biological or mechanical roles have been proposed for the ligament. Unless these are disproved, the use of surgical procedures that sacrifice the ligamentum teres, as in surgical dislocation of the hip, should be carefully considered. This paper provides an update on the development, structure and function of the ligamentum teres, and discusses associated clinical implications.

The October 2012 Wrist & Hand Roundup³⁶⁰ looks at: osteoarticular flaps to the PIPJ; prognosis after wrist arthroscopy; adipofascial flaps and post-traumatic adhesions; the torn TFCC alone; ulna-shortening osteotomy for ulnar impaction syndrome; Dupuytren’s disease; when a wrist sprain is not a sprain; and shrinking the torn intercarpal ligament.

We evaluated the efficacy of Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E-BMP-2) in a mini-pig model of spinal anterior interbody fusion. A total of 14 male mini-pigs underwent three-level anterior lumbar interbody fusion using polyether etherketone (PEEK) cages containing porous hydroxyapatite (HA). Four groups of cages were prepared: 1) control (n = 10 segments); 2) 50 μg E-BMP-2 (n = 9); 3) 200 μg E-BMP-2 (n = 10); and 4) 800 μg E-BMP-2 (n = 9). At eight weeks after surgery the mini-pigs were killed and the specimens were evaluated by gross inspection and manual palpation, radiological evaluation including plain radiographs and micro-CT scans, and histological analysis. Rates of fusion within PEEK cages and overall union rates were calculated, and bone formation outside vertebrae was evaluated. One animal died post-operatively and was excluded, and one section was lost and also excluded, leaving 38 sites for assessment. This rate of fusion within cages was 30.0% (three of ten) in the control group, 44.4% (four of nine) in the 50 μg E-BMP-2 group, 60.0% (six of ten) in the 200 μg E-BMP-2 group, and 77.8% (seven of nine) in the 800 μg E-BMP-2 group. Fusion rate was significantly increased by the addition of E-BMP-2 and with increasing E-BMP-2 dose (p = 0.046). In a mini-pig spinal anterior interbody fusion model using porous HA as a carrier, the implantation of E-BMP-2-loaded PEEK cages improved the fusion rate compared with PEEK cages alone, an effect that was significantly increased with increasing E-BMP-2 dosage.

Cite this article: Bone Joint J 2013;95-B:217–23.

Hyaline articular cartilage has been known to be a troublesome tissue to repair once damaged. Since the introduction of autologous chondrocyte implantation (ACI) in 1994, a renewed interest in the field of cartilage repair with new repair techniques and the hope for products that are regenerative have blossomed. This article reviews the basic science structure and function of articular cartilage, and techniques that are presently available to effect repair and their expected outcomes.

The August 2012 Research Roundup³⁶⁰ looks at: PRP and chondrogenic differentiation; basic fibroblast growth factor; whether glucosamine works; randomised trials; ossification of the ligamentum flavum; treadmill running; inhibiting BMP antagonists; and whether NSAIDs delay union after all.

Deformity of the forearm due to growth disturbance of the ulna occurs in a number of conditions such as ulnar deficiency, multiple exostoses, and neurofibromatosis. We report a previously unrecognised form, caused by focal cortical indentation.

We have treated five children with this condition, three girls and two boys; the mean age at presentation was 5 years (2 to 8). The deformity was first recognised about the age of two years, and progressed gradually. The radiological findings were the same in all cases. The focal cortical indentation was seen at the distal end of the ulna with anteromedial bowing and dysplasia. The radial head was dislocated posterolaterally. In one patient the histological findings at the site of indentation were of a fold of tissue resembling periosteum, which interfered with enchondral ossification. Treatment by ulnar lengthening using an external fixator and osteotomy which corrected both the ulnar deformity and reduced the dislocated radial head in two cases gave the best results.

The August 2012 Wrist & Hand Roundup³⁶⁰ looks at: the Herbert ulnar head prosthesis; the five-year outcome for wrist arthroscopic surgery; four-corner arthrodesis with headless screws; balloon kyphoplasty for Kienböck's disease; Mason Type 2 radial head fractures; local infiltration and intravenous regional anaesthesia for endoscopic carpal tunnel release; perilunate injuries; and replanting the amputated fingertip.

The August 2012 Children’s orthopaedics Roundup³⁶⁰ looks at: whether 3D-CT gives a better idea of coverage than plain radiographs; forearm fractures after trampolining accidents; forearm fractures and the Rush pin; the fractured distal radius; elastic stable intramedullary nailing for long-bone fractures; aponeurotic recession for the equinus foot; the torn medial patellofemoral ligament and the adductor tubercle; slipped capital femoral epiphysis; paediatric wrist arthroscopy; and Pirani scores and clubfoot.

Most fractures of the radial head are stable undisplaced or minimally displaced partial fractures without an associated fracture of the elbow or forearm or ligament injury, where stiffness following non-operative management is the primary concern. Displaced unstable fractures of the radial head are usually associated with other fractures or ligament injuries, and restoration of radiocapitellar contact by reconstruction or prosthetic replacement of the fractured head is necessary to prevent subluxation or dislocation of the elbow and forearm. In fractures with three or fewer fragments (two articular fragments and the neck) and little or no metaphyseal comminution, open reduction and internal fixation may give good results. However, fragmented unstable fractures of the radial head are prone to early failure of fixation and nonunion when fixed. Excision of the radial head is associated with good long-term results, but in patients with instability of the elbow or forearm, prosthetic replacement is preferred.

This review considers the characteristics of stable and unstable fractures of the radial head, as well as discussing the debatable aspects of management, in light of the current best evidence.

Cite this article: Bone Joint J 2013;95-B:151–9.

The April 2012 Wrist & Hand Roundup³⁶⁰ looks at releasing the trigger finger, function in the osteoarthritic hand, complex regional pain syndrome, arthroscopic ligamentoplasty for the injured scapholunate ligament, self-concept and upper limb deformities in children, wrist arthroscopy in children, internal or external fixation for the fractured distal radius, nerve grafting, splinting the PIPJ contracture, and finding the stalk of a dorsal wrist ganglion

Acetabular dysplasia was produced in 24 immature white rabbits. A rotational acetabular osteotomy was then carried out and radiological and histological studies of the articular cartilage were made.

In the hips which did not undergo osteotomy, radiographs at 26 weeks showed that residual subluxation remained and arthritic changes such as narrowing of the joint space or dislocation were still seen. However, in the operated group there was a remarkable increase in cover, but arthritic changes were not observed. After 24 weeks, the Mankin grading score in the operated group was significantly lower than that in the non-operated group. The latter hips showed an irregular surface of the cartilage, exfoliation and proliferation of synovial tissue. In those undergoing osteotomy, primary cloning of chondrocytes or hypercellularity was seen and at 24 weeks after operation and metaplasia of the cartilage in the fibrous tissue was observed in the boundary between the medial area of the acetabulum and the acetabular fossa.

The purpose of this study was to evaluate the long-term functional and radiological outcomes of arthroscopic removal of unstable osteochondral lesions with subchondral drilling in the lateral femoral condyle. We reviewed the outcome of 23 patients (28 knees) with stage III or IV osteochondritis dissecans lesions of the lateral femoral condyle at a mean follow-up of 14 years (10 to 19). The functional clinical outcomes were assessed using the Lysholm score, which improved from a mean of 38.1 (sd 3.5) pre-operatively to a mean of 87.3 (sd 5.4) at the most recent review (p = 0.034), and the Tegner activity score, which improved from a pre-operative median of 2 (0 to 3) to a median of 5 (3 to 7) at final follow-up (p = 0.021). The radiological degenerative changes were evaluated according to Tapper and Hoover’s classification and when compared with the pre-operative findings, one knee had grade 1, 22 knees had grade 2 and five knees had grade 3 degenerative changes. The overall outcomes were assessed using Hughston’s rating scale, where 19 knees were rated as good, four as fair and five as poor.

We found radiological evidence of degenerative changes in the third or fourth decade of life at a mean of 14 years after arthroscopic excision of the loose body and subchondral drilling for an unstable osteochondral lesion of the lateral femoral condyle. Clinical and functional results were more satisfactory.

There have been very few reports in the literature of gout and pseudogout of the spine. We describe six patients who presented with acute sciatica attributable to spinal stenosis with cyst formation in the facet joints. Cytopathological studies confirmed the diagnosis of crystal arthropathy in each case.

Specific formation of a synovial cyst was identified pre-operatively by MRI in five patients. In the sixth, the diagnosis was made incidentally during decompressive surgery. Surgical decompression alone was undertaken in four patients. In one with an associated degenerative spondylolisthesis, an additional intertransverse fusion was performed. Another patient had previously undergone a spinal fusion adjacent to the involved spinal segment, and spinal stabilisation was undertaken as well as a decompression.

In addition to standard histological examination material was sent for examination under polarised light which revealed deposition of urate or calcium pyrophosphate dihydrate crystals in all cases.

It is not possible to diagnose gout and pseudogout of the spine by standard examination of a fixed specimen. However, examining dry specimens under polarised light suggests that crystal arthropathy is a significant aetiological factor in the development of symptomatic spinal stenosis associated with cyst formation in a facet joint.

Ovine articular chondrocytes were isolated from cartilage biopsy and culture expanded in vitro. Approximately 30 million cells per ml of cultured chondrocytes were incorporated with autologous plasma-derived fibrin to form a three-dimensional construct. Full-thickness punch hole defects were created in the lateral and medial femoral condyles. The defects were implanted with either an autologous ‘chondrocyte-fibrin’ construct (ACFC), autologous chondrocytes (ACI) or fibrin blanks (AF) as controls. Animals were killed after 12 weeks. The gross appearance of the treated defects was inspected and photographed. The repaired tissues were studied histologically and by scanning electron microscopy analysis.

All defects were assessed using the International Cartilage Repair Society (ICRS) classification. Those treated with ACFC, ACI and AF exhibited median scores which correspond to a nearly-normal appearance. On the basis of the modified O’Driscoll histological scoring scale, ACFC implantation significantly enhanced cartilage repair compared to ACI and AF. Using scanning electron microscopy, ACFC and ACI showed characteristic organisation of chondrocytes and matrices, which were relatively similar to the surrounding adjacent cartilage.

Implantation of ACFC resulted in superior hyaline-like cartilage regeneration when compared with ACI. If this result is applicable to humans, a better outcome would be obtained than by using conventional ACI.