This pilot study analysed the outcome of open versus endoscopic curettage and bone grafting for the treatment of simple calcaneal bone cysts. A total of 26 patients were evaluated into two equal groups: group 1 was treated with traditional open curettage and bone grafting and group 2 was treated with endoscopic curettage and percutaneous bone grafting. Cyst size, operating time, length of stay, time to healing, complications, further surgery and radiological healing were recorded and differences were statistically compared. The mean age of the patients was 22.9 years (18 to 28) and the mean follow-up was 28.7 months (24 to 36). There were no statistically significant differences in regard to age of patients, cyst size and the follow-up periods in the two groups. The operating time and mean length of stay of group 2 patients was significantly shorter than group 1 patients (p <  0.001). The time to healing was similar in the two groups. The overall success rates for groups 1 and 2 were 92.3% (12 of 13) and 100% (13 of 13), respectively, and there were no statistically significant differences regarding radiological healing. This pilot study suggests that endoscopic curettage and percutaneous grafting is a simple and safe form of treatment, with similar results to those following open treatment

Aims. The purpose of this study was to assess the success rate and functional outcomes of bone grafting for periprosthetic bone cysts following total ankle arthroplasty (TAA). Additionally, we evaluated the rate of graft incorporation and identified associated predisposing factors using CT scan. Methods. We reviewed a total of 37 ankles (34 patients) that had undergone bone grafting for periprosthetic bone cysts. A CT scan was performed one year after bone grafting to check the status of graft incorporation. For accurate analysis of cyst volumes and their postoperative changes, 3D-reconstructed CT scan processed with 3D software was used. For functional outcomes, variables such as the Ankle Osteoarthritis Scale score and the visual analogue scale for pain were measured. Results. Out of 37 ankles, graft incorporation was successful in 30 cases. Among the remaining seven cases, four (10.8%) exhibited cyst re-progression, so secondary bone grafting was needed. After secondary bone grafting, no further progression has been noted, resulting in an overall 91.9% success rate (34 of 37) at a mean follow-up period of 47.5 months (24 to 120). The remaining three cases (8.1%) showed implant loosening, so tibiotalocalcaneal arthrodesis was performed. Functional outcomes were also improved after bone grafting in all variables at the latest follow-up (p < 0.05). The mean incorporation rate of the grafts according to the location of the cysts was 84.8% (55.2% to 96.1%) at the medial malleolus, 65.1% (27.6% to 97.1%) at the tibia, and 81.2% (42.8% to 98.7%) at the talus. Smoking was identified as a significant predisposing factor adversely affecting graft incorporation (p = 0.001). Conclusion. Bone grafting for periprosthetic bone cysts following primary TAA is a reliable procedure with a satisfactory success rate and functional outcomes. Regular follow-up, including CT scan, is important for the detection of cyst re-progression to prevent implant loosening after bone grafting. Cite this article: Bone Joint J 2024;106-B(5):475–481

Aims. We report the natural course of Baker’s cysts following total knee arthroplasty (TKA) at short- and mid-term follow-up. Methods. In this prospective case series, 105 TKA patients were included. All patients who received surgery had a diagnosis of primary osteoarthritis and had preoperatively presented with a Baker’s cyst. Sonography and MRI were performed to evaluate the existence and the gross size of the cyst before TKA, and sonography was repeated at a mean follow-up time of 1.0 years (0.8 to 1.3; short-term) and 4.9 years (4.0 to 5.6; mid-term) after TKA. Symptoms potentially attributable to the Baker’s cyst were recorded at each assessment. Results. At the one-year follow-up analysis, 102 patients were available. Of those, 91 patients were available for the 4.9-year assessment (with an 86.7% follow-up rate (91/105)). At the short- and mid-term follow-up, a Baker’s cyst was still present in 87 (85.3%) and 30 (33.0%) patients, respectively. Of those patients who retained a Baker’s cyst at the short-term follow-up, 31 patients (35.6%) had popliteal symptoms. Of those patients who continued to have a Baker’s cyst at the mid-term follow-up, 17 patients (56.7%) were still symptomatic. The mean preoperative cyst size was 14.5 cm. 2. (13.1 to 15.8). At the short- and mid-term follow-up, the mean cyst size was 9.7 cm. 2. (8.3 to 11.0) and 10.4 cm. 2. (9.8 to 11.4), respectively. A significant association was found between the size of the cyst at peroperatively and the probability of resolution, with lesions smaller than the median having an 83.7% (36/43) probability of resolution, and larger lesions having a 52.1% (25/48) probability of resolution (p < 0.001). At the mid-term follow-up, no association between cyst size and popliteal symptoms was found. Conclusion. At a mean follow-up of 4.9 years (4.0 to 5.6) after TKA, the majority (67.0%, 61/91) of the Baker’s cysts that were present preoperatively had disappeared. The probability of cyst resolution was dependent on the size of the Baker’s cyst at baseline, with an 83.7% (36/43) probability of resolution for smaller cysts and 52.1% (25/48) probability for larger cysts. Cite this article: Bone Joint J. 2020;102-B(1):132–136

Aims. The aim of this study is to evaluate the surgical treatment with the best healing rate for patients with proximal femoral unicameral bone cysts (UBCs) after initial surgery, and to determine which procedure has the lowest adverse event burden during follow-up. Methods. This multicentre retrospective study was conducted in 20 tertiary paediatric hospitals in France, Belgium, and Switzerland, and included patients aged < 16 years admitted for UBC treatment in the proximal femur from January 1995 to December 2017. UBCs were divided into seven groups based on the index treatment, which included elastic stable intramedullary nail (ESIN) insertion with or without percutaneous injection or grafting, percutaneous injection alone, curettage and grafting alone, and insertion of other orthopaedic hardware with or without curettage. Results. A total of 201 patients were included in the study. The mean age at diagnosis was 8.7 years (SD 3.9); 77% (n = 156) were male. The mean follow-up was 9.4 years (SD 3.9). ESIN insertion without complementary procedure had a 67% UBC healing rate after the first operation (vs 30% with percutaneous injection alone (p = 0.027), 43% with curettage and grafting (p = 0.064), and 21% with insertion of other hardware combined with curettage (p < 0.001) or 36% alone (p = 0.014)). ESIN insertion with percutaneous injection presented a 79% healing rate, higher than percutaneous injection alone (p = 0.017), curettage and grafting (p = 0.028), and insertion of other hardware combined with curettage (p < 0.001) or alone (p = 0.014). Patients who underwent ESIN insertion with curettage had a 53% healing rate, higher than insertion of other hardware combined with curettage (p = 0.009). The overall rate of postoperative complications was 25% and did not differ between groups (p = 0.228). A total of 32 limb length discrepancies were identified. Conclusion. ESIN insertion, either alone or combined with percutaneous injection or curettage and grafting, may offer higher healing rates than other operative procedures. Limb length discrepancy remains a major concern, and might be partly explained by the cyst’s location and the consequence of surgery. Therefore, providing information about this risk is crucial. Cite this article: Bone Joint J 2024;106-B(5):508–514

Aims. It is widely held that most Baker’s cysts resolve after treatment of the intra-articular knee pathology. The present study aimed to evaluate the fate of Baker’s cysts and their associated symptoms after total knee arthroplasty (TKA). Patients and Methods. In this prospective cohort study, 102 patients with (105 were included, however three were lost to follow-up) an MRI-verified Baker’s cyst, primary osteoarthritis and scheduled for TKA were included. Ultrasound was performed to evaluate the existence and the gross size of the cyst before and at one year after TKA. Additionally, associated symptoms of Baker's cyst were recorded pre- and post-operatively. Results. After one year, a Baker’s cyst was still present in 87 patients (85%). There was a significant reduction in associated symptoms arising from the Baker’s cyst before (71%) to after surgery (31%). No patients developed a new Baker’s cyst associated symptoms. However, of the 72 patients who had reported Baker’s cyst associated symptoms pre-operatively, 32 patients (44%) still complained of such symptoms one year after surgery. Conclusion. Baker’s cysts had resolved in only a small number of patients (15%) one year after TKA and symptoms from the cysts persisted in 31%. Cite this article: Bone Joint J 2016;98-B:1185–8

Aims. The pathogenesis of intraneural ganglion cysts is controversial. Recent reports in the literature described medial plantar intraneural ganglion cysts (mIGC) with articular branches to subtalar joints. The aim of the current study was to provide further support for the principles underlying the articular theory, and to explain the successes and failures of treatment of mICGs. Patients and Methods. Between 2006 and 2017, five patients with five mICGs were retrospectively reviewed. There were five men with a mean age of 50.2 years (33 to 68) and a mean follow-up of 3.8 years (0.8 to 6). Case history, physical examination, imaging, and intraoperative findings were reviewed. The outcomes of interest were ultrasound and/or MRI features of mICG, as well as the clinical outcomes. Results. The five intraneural cysts followed the principles of the unifying articular theory. Connection to the posterior subtalar joint (pSTJ) was identified or suspected in four patients. Re-evaluation of preoperative MRI demonstrated a degenerative pSTJ and denervation changes in the abductor hallucis in all patients. Cyst excision with resection of the articular branch (four), cyst incision and drainage (one), and percutaneous aspiration/steroid injection (two) were performed. Removing the connection to the pSTJ prevented recurrence of mIGC, whereas medial plantar nerves remained cystic and symptomatic when resection of the communicating articular branch was not performed. Conclusion. Our findings support a standardized treatment algorithm for mIGC in the presence of degenerative disease at the pSTJ. By understanding the pathoanatomic mechanism for every cyst, we can improve treatment that must address the articular branch to avoid the recurrence of intraneural ganglion cysts, as well as the degenerative pSTJ to avoid extraneural cyst formation or recurrence. Cite this article: Bone Joint J 2018;100-B:183–9

Aims. The aim of this study was to analyze the complications and outcomes of treatment in a series of previously untreated patients with a primary aneurysmal bone cyst (ABC) who had been treated by percutaneous sclerosant therapy using polidocanol. Methods. Between January 2010 and December 2016, 56 patients were treated primarily with serial intralesional sclerosant injections. Their mean age was 20 years (1 to 54). The sites involved were clavicle (n = 3), humeri (n = 11), radius (n = 1), ulna (n = 3), hand (n = 2), pelvis (n = 12), femur (n = 7), tibia (n = 13), fibula (n = 3), and foot (n = 1). After histopathological confirmation of the diagnosis, 3% polidocanol (hydroxypolyaethoxydodecan) was injected into the lesion under image intensifier guidance. Patients were evaluated clinically and radiologically every six to eight weeks. In the absence of clinical and/or radiological response, a repeat sclerosant injection was given after eight to 12 weeks and repeated at similar intervals if necessary. Results. There were no complications of treatment. One patient was lost to follow-up. Overall, 46/55 (84%) of lesions healed after one or more injections of polidocanol: 24/55 (44%) patients healed with a single injection, and 43/55 (78%) within two injections. Of these 46, four (9%) patients developed local recurrence, two of whom healed with a repeat sclerosant injection. Thus, 44/55 (80%) patients of primary ABC healed with sclerotherapy. The mean follow-up was 62 months (20 to 111). The local recurrence free survival (LRFS) with percutaneous sclerosant therapy with polidocanol was 100%, 98% (95% confidence interval (CI) 85 to 100) and 93% (95% CI 78 to 98) at two, three, and five years, respectively. Conclusion. Percutaneous sclerotherapy using polidocanol is a safe, effective, minimally invasive and inexpensive method of treating a primary ABC of the limbs or pelvis. Cite this article: Bone Joint J 2020;102-B(2):186–190

Aims. The aim of this study was to evaluate antegrade autologous bone grafting with the preservation of articular cartilage in the treatment of symptomatic osteochondral lesions of the talus with subchondral cysts. Patients and Methods. The study involved seven men and five women; their mean age was 35.9 years (14 to 70). All lesions included full-thickness articular cartilage extending through subchondral bone and were associated with subchondral cysts. Medial lesions were exposed through an oblique medial malleolar osteotomy, and one lateral lesion was exposed by expanding an anterolateral arthroscopic portal. After refreshing the subchondral cyst, it was grafted with autologous cancellous bone from the distal tibial metaphysis. The fragments of cartilage were fixed with 5-0 nylon sutures to the surrounding cartilage. Function was assessed at a mean follow-up of 25.3 months (15 to 50), using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot outcome score. The radiological outcome was assessed using MRI and CT scans. Results. The mean AOFAS score improved from 65.7 (47 to 81) preoperatively to 92 (90 to 100) at final follow-up, with 100% patient satisfaction. The radiolucent area of the cysts almost disappeared on plain radiographs in all patients immediately after surgery, and there were no recurrences at the most recent follow-up. The medial malleolar screws were removed in seven patients, although none had symptoms. At this time, further arthroscopy was undertaken, when it was found that the mean International Cartilage Repair Society (ICRS) arthroscopic score represented near-normal cartilage. Conclusion. Autologous bone grafting with fixation of chondral fragments preserves the original cartilage in the short term, and could be considered in the treatment for adult patients with symptomatic osteochondral defect and subchondral cysts. Cite this article: Bone Joint J 2018;100-B:590–5

Aims. Aneurysmal bone cysts (ABCs) are locally aggressive lesions typically found in the long bones of children and adolescents. A variety of management strategies have been reported to be effective in the treatment of these lesions. The purpose of this review was to assess the effectiveness of current strategies for the management of primary ABCs of the long bones. Methods. A systematic review of the published literature was performed to identify all articles relating to the management of primary ABCs. Studies required a minimum 12-month follow-up and case series reporting on under ten participants were not included. Results. A total of 28 articles meeting the eligibility criteria were included in this review, and all but one were retrospective in design. Due to heterogeneity in study design, treatment, and outcome reporting, data synthesis and group comparison was not possible. The most common treatment option reported on was surgical curettage with or without a form of adjuvant therapy, followed by injection-based therapies. Of the 594 patients treated with curettage across 17 studies, 86 (14.4%) failed to heal or experienced a recurrence. Similar outcomes were reported for 57 (14.70%) of the 387 patients treated with injection therapy across 12 studies. Only one study directly compared curettage with injection therapy (polidocanol), randomizing 94 patients into both treatment groups. This study was at risk of bias and provided low-quality evidence of a lack of difference between the two interventions, reporting success rates of 93.3% and 84.8% for injection and surgical treatment groups, respectively. Conclusion. While both surgery and sclerotherapy are widely implemented for treatment of ABCs, there is currently no good quality evidence to support the use of one option over the other. There is a need for prospective multicentre randomized controlled trials (RCTs) on interventions for the treatment of ABCs. Cite this article: Bone Jt Open 2021;2(2):125–133

We report the results of the treatment of nine children with an aneurysmal bone cyst of the distal fibula (seven cysts were juxtaphyseal, and two metaphyseal). The mean age of the children was 10 years and 3 months (7 years and 4 months to 12 years and 9 months). All had open physes. All cysts were active and in seven cases substituted and expanded the entire width of the bone (type-2 lesions). The mean longitudinal extension was 5.7 cm (3 to 10). The presenting symptoms were pain, swelling and pathological fracture. Moderate fibular shortening was evident in one patient. In six patients curettage was performed, using phenol as adjuvant in three. Three with juxtaphyseal lesions underwent resection. A graft from the contralateral fibula (one case) and allografts (two cases) were positioned at the edge of the physis for reconstruction. The mean follow-up was 11.6 years (3.1 to 27.5). There was no recurrence. At the final follow-up there was no significant difference in the American Orthopaedic Foot and Ankle Society scores (excellent/good in all cases) and in growth disturbance, alignment, stability and bone reconstitution, but in the resection group the number of operations, including removal of hardware, complications (two minor) and time of immobilisation/orthosis, were increased. Movement of the ankle was restricted in one patient. The potential risks in the management of these lesions include recurrence, physeal injury, instability of the ankle and hardware and graft complications. Although resection is effective it should be reserved for aggressive or recurrent juxtaphyseal lesions

Open surgery is rarely justified for the initial treatment of a unicameral bone cyst, but there is some debate concerning the relative effectiveness of closed methods. This study compared the results of steroid injection with those of autologous bone marrow grafting for the treatment of unicameral bone cysts. Between 1990 and 2001, 30 patients were treated by steroid injection and 28 by grafting with autologous bone marrow. The overall success rates were 86.7% and 92.0%, respectively (p > 0.05). The success rate after the initial procedure was 23.3% in the steroid group and 52.0% in those receiving autologous bone marrow (p < 0.05), and the respective cumulative success rates after second injections were 63.3% and 80.0% (p > 0.05). The mean number of procedures required was 2.19 (1 to 5) and 1.57 (1 to 3) (p < 0.05), the mean interval to healing was 12.5 months (4 to 32) and 14.3 months (7 to 36) (p > 0.05), and the rate of recurrence after the initial procedure was 41.7% and 13.3% in the steroid and in the autologous bone marrow groups, respectively (p < 0.05). Although the overall rates of success of both methods were similar, the steroid group had higher recurrence after a single procedure and required more injections to achieve healing

From a total of 1571 surgically excised menisci, 112 (7.1 per cent) were found by gross and microscopic examination to contain one or more cysts. All of these cysts were associated with tears, either primarily horizontal or with a horizontal component. Tracks were often demonstrable leading from the tear to the cysts, and in some cases of osteoarthritis, detritus of bone could be found in their periphery. It is concluded that the cysts are fuelled by synovial fluid. The relationship of cysts to "myxoid" change of the meniscus is discussed

1. The cause of cyst formation lies in the major overloading of certain regions caused by the unevenness of the articular surface produced by the arthritic process. 2. Photoelasticity investigations disclose an overburdening of the bone beneath the surface of the joint, which in turn markedly resembles the shapes of actual cysts. 3. The results of this investigation fit organically into the logical sequence of processes in accordance with our theory. 4. This theory is further borne out by the successful formation of cyst phenomena in healthy joints by overloading (Trias 1961). 5. Our theory has no immediate practical bearing on the treatment of arthritic cysts. However, it uncovers certain interesting aspects of the behaviour of bone tissues under mechanical overloading above the limits of biological, though below those of mechanical bearing capacity. Conclusions arising therefrom might in many respects be useful in research into the physiology of bone

The internal pressure of simple bone cysts was found to be slightly higher than the normal pressure of the bone marrow in the contralateral limb. The pressure within the cyst was measured during drilling with a Kirschner wire; it gradually decreased as the number of drill-holes increased. The PO2 of the cyst fluid was markedly lower than that of either venous or arterial blood measured synchronously. It is suggested that venous obstruction in the bone is the likely cause of these cysts. Seven patients with simple bone cysts were treated by the multiple drill-hole method, and the clinical outcome was excellent. Multiple drilling may prove to be the treatment of choice for simple bone cysts in the younger patient, as it presents fewer hazards than other procedures

Aneurysmal bone cyst is a rare tumour-like lesion which develops during growth. Our aim was to determine the efficacy of the administration of percutaneous intralesional 3% polidocanol (hydroxypolyaethoxydodecan) as sclerotherapy. Between July 1997 and December 2004 we treated 72 patients (46 males, 26 females) with a histologically-proven diagnosis of aneurysmal bone cyst, at various skeletal sites using this method. The sclerotherapy was performed under fluoroscopic guidance and general anaesthesia or sedation and local anaesthesia. The mean follow-up period was 34 months (26.5 to 80). The patients were evaluated using the Enneking system for functional assessment and all the lesions were radiologically quantified into four grades. The mean age of patients was 15.6 years (3 to 38) and the mean number of injections was three (1 to 5). Ten patients were cured by a single injection. The mean reduction in size of the lesion (radiological healing) was found to be 76.6% (61.9% to 93.2%) with a mean clinical response of 84.5% (73.4% to 100%). Recurrence was seen in two patients (2.8%) within two years of treatment and both were treated successfully by further sclerotherapy. Percutaneous sclerotherapy with polidocanol is a safe alternative to conventional surgery for the treatment of an aneurysmal bone cyst. It can be used at surgically-inaccessible sites and treatment can be performed on an out-patient basis

A total of 254 cases of synovial cysts of the spine have been reported in the English literature, but only eight have been associated with haemorrhagie. We describe a 55-year-old man with acute radiculopathy resulting from haemorrhage involving a synovial cyst at a lumbar facet joint. Traumatic factors could have caused bleeding around or into the synovial cyst. Treatment by resection of the cyst and evacuation of the haematoma led to complete neurological recovery

1. Anterior synovectomy was undertaken in sixteen knees of fourteen patients with rheumatoid arthritis associated with popliteal or calf cysts. Subsequent changes in the knees and cysts were observed clinically and by arthrography. 2. In all instances there was alleviation of symptoms and in fourteen cases the cysts disappeared. 3. It is suggested that anterior synovectomy is the logical treatment of a posterior cyst associated with rheumatoid arthritis of the knee

In a series of 1160 arthroscopies we found 16 meniscal cysts; 12 involved the lateral joint line and two the medial, and two were intra-articular. In all but two cases, arthroscopy showed meniscal tears. We recommend arthroscopy of all cases to correct the meniscal lesion, and to evacuate the cyst into the joint by opening the joint capsule. This was successful in 12 cases, with no recurrence after an average follow-up of 18 months. Only two patients with no meniscal lesion on arthroscopy required an additional external incision for cyst removal

Old calcified fibrin coagula are frequently found in simple bone cysts. They provide a scaffold on which new bone is laid down, in a process analogous to endochondral ossification. It is suggested that these coagula are derived in substantial part from the plasma-like contents of the cyst, after the release of plasma-clotting factors as the result of injury. Major haemorrhage is not involved and in many cases there is no antecedent fracture. The phenomenon is not seen in other common cystic conditions of bone and its recognition is thus helpful in the histological diagnosis of simple bone cyst. Cystic bone infarcts and their possible confusion with simple bone cysts are also briefly discussed

We report a case of local compression-induced transient femoral nerve palsy in a 46-year-old man. He had previously undergone surgical release of the soft tissues anterior to both hip joints because of contractures following spinal injury. An MRI scan confirmed a synovial cyst originating from the left hip joint, lying adjacent to the femoral nerve. The cyst expanded on standing, causing a transient femoral nerve palsy. The symptoms resolved after excision of the cyst