Aims

The prevalence of osteoarthritis (OA) associated with instability of the shoulder ranges between 4% and 60%. Articular cartilage is, however, routinely assessed in these patients using radiographs or scans (2D or 3D), with little opportunity to record early signs of cartilage damage. The aim of this study was to assess the prevalence and localization of chondral lesions and synovial damage in patients undergoing arthroscopic surgery for instablility of the shoulder, in order to classify them and to identify risk factors for the development of glenohumeral OA.

Objective of the study. To determine if the location and pattern of knee pain as described by the patients using the knee pain map was comparable with the intra articular pathology found on arthroscopy as well as to facilitate diagnosis based on pain. Methods. There were Sixty consecutive patients with acute and chronic knee pain participating in the study and they subsequently underwent arthroscopy of the knee joint as therapeutic or diagnostic procedure in day surgery. Those patients with extra articular pathologies, referred pain hip, back and foot were excluded from the study. All the participants were consented for the study; subjective data was recorded on the standardised knee pain map that included visual analogue pain scale preoperatively on the day of admission for arthroscopy. The findings of the arthroscopy including EUA were recorded on the on standard arthroscopy forms used in our department by the operating surgeon. Results. Patients on the knee pain map most often recorded sharp/stabbing pain (72%), followed by diffuse dull pain (14.5%), mixed dull and sharp pain (10 %) and burning pain (3.5%). 78 % of the localising pain pattern recorded on the knee pain map by the patients corresponded to the intra articular lesion found during knee arthroscopy. 18 % of the pain mapping location and pattern were not very specific to the intrarticular arthroscopic lesions and the rest were non specific. Conclusions. The majority of the patients could map the knee pain location and pattern correlating to the knee arthroscopic findings. The results from our study indicate that knee pain mapping can be used as a reliable tool to assist the clinician to determine the specific knee pain patterns correlating with discrete pathologic findings knee intra articular lesion

The August 2014 Shoulder & Elbow Roundup. 360 . looks at: Myofibroblasts perhaps not implicated in post-traumatic elbow stiffness; olecranon tip biomechanically sound for coranoid reconstruction; obesity and elbow replacement don’t mix; single column plating successful for extra-articular distal humeral fractures; satisfaction not predictable in frozen shoulder; tenodesis and repair both acceptable in Grade II SLAP tears; glenoid bone grafting is effective and glenohumeral articular lesions best seen with an arthroscope

Purpose: Hyaline cartilage lesion in a large weight bearing joint can lead, if not treated, to damage of the subchondral bone. Since cartilage tissue does not heal spontaneously, nor can it regenerate, joint functional restitution is based on temporary biological solutions. The only promising approach for recovering damaged joint and avoid its eventual deterioration is to restore the genuine surfacing of hyaline cartilage. Methods: We have developed a novel primary chondrocytes culture based on a unique source of cartilage cells whereby a gradual collagenase separation yield a homogenous chondrocyte population, which unlike other cartilage source-derived cells preserve the capability of spontaneous differentiation into cartilage forming cells. Results: Following a short period of intensive proliferation, the cells start to differentiate into polygonal shaped cells, expressing Cbfa1-the skeletal tissues specific transcription factor, type II collagen and cartilage proteoglycan; thus producing a genuine hyaline cartilage. The cultured chondrocytes also preserve their responsiveness toward local and systemic factors such as growth hormone, insulin, PTH and IGF1. Since, cartilage is an immuno-privileged tissue; non- autologous cartilage sources may also be successfully transplanted. We have shown that mourine and porcine-derived cells injected into rats afflicted (AIA) joints replenish the articular lesion with no signs of WBC infiltration. Since, prior to differentiation, these cells undergo an intensive proliferation phase they can also be transfected. We have also shown that osteoprotegerin (OPG)-firstly known for its activity as RANK ligand decoy receptor, has direct ameliorative effects on cartilage development. We have shown that OPG transfected chondrocytes preserve their typical morphological and functional features. Conclusions: This model of primary chondrocyte culture, develop authentic resemblance to hyaline (surfacing) cartilage with similar physical and mechanical properties of the original tissue. These cells can be successfully transplanted into damaged joint of a foreign host. Hence, we propose that these primary spontaneously-differentiating chondrocytes, from non autologous source- can be suitable for replenishment of articular lesions as well as vehicle for local application of beneficial cytokines like OPG

Surgical reconstruction of articular surfaces by transplantation of osteochondral autografts has shown considerable promise in the treatment of focal articular lesions. During mosaicplasty, each cylindrical osteochondral graft is centred over the recipient hole and delivered by impacting the articular surface. Impact loading of articular cartilage has been associated with structural damage, loss of the viability of chondrocytes and subsequent degeneration of the articular cartilage. We have examined the relationship between single-impact loading and chondrocyte death for the specific confined-compression boundary conditions of mosaicplasty and the effect of repetitive impact loading which occurs during implantation of the graft on the resulting viability of the chondrocytes. Fresh bovine and porcine femoral condyles were used in this experiment. The percentage of chondrocyte death was found to vary logarithmically with single-impact energy and was predicted more strongly by the mean force of the impact rather than by the number of impacts required during placement of the graft. The significance of these results in regard to the surgical technique and design features of instruments for osteochondral transplantation is discussed

Aims

The study aimed to assess the clinical outcomes of arthroscopic debridement and partial excision in patients with traumatic central tears of the triangular fibrocartilage complex (TFCC), and to identify prognostic factors associated with unfavourable clinical outcomes.

Aim. To determine if the location and pattern of knee pain as described by the patients using the knee pain map was comparable with the intra articular pathology found on arthroscopy as well as to facilitate diagnosis based on pain. Methods. There were fifty five consecutive patients with acute and chronic knee pain participating in the study and they subsequently underwent arthroscopy of the knee joint as therapeutic or diagnostic procedure in day surgery. Those patients with extra articular pathologies, referred pain hip, back and foot were excluded from the study. All the participants were consented for the study; subjective data was recorded on the standardised knee pain map that included visual analogue pain scale preoperatively on the day of admission for arthroscopy. The findings of the arthroscopy including EUA were recorded on the on standard arthroscopy forms used in our department by the operating surgeon. Results. Patients on the knee pain map most often recorded sharp/stabbing pain (72%), followed by diffuse dull pain (14.5%), mixed dull and sharp pain (10 %) and burning pain (3.5%). 82% of the localising pain pattern recorded on the knee pain map by the patients corresponded to the intra articular lesion found during knee arthroscopy. 18 % of the pain mapping location and pattern was not very specific to the intrarticular arthroscopic lesions. Conclusions. The results from our study indicate, majority of the patients could map the knee pain location and pattern correlating to the knee arthroscopic findings. Furthermore, the knee pain mapping can be used as a reliable tool to assist the clinician to determine the specific knee pain patterns correlating with intra-articular lesion

A prospective study was made of 100 knees which had been operated on for various kinds of internal derangement. An observer, who did not know the clinical condition of the knee, recorded whether or not there were articular lesions of the femoral condyles. Lesions were found to be localised to a triangular area on the medial condyle and to a strip on the lateral condyle. Similar lesions have been described in association with flexion deformities in rheumatoid and osteoarthritic knees. Lesions were found in 49 out of 50 knees which had been locked for more than three days. They were also found in 29 knees in which there appeared to be full extension before operation, but where there was either a torn meniscus with a history of intermittent locking or serious anterolateral instability. In these cases it was considered that the final "screw-home" mechanism of full extension had been lost. Lesions were not present in 10 knees which appeared locked, but in nine of these the interval between injury and operation was less than three days. Lesions were not found in eight knees where there was full extension and no history of locking or instability. In four knees with a plica syndrome similar lesions were present

INTRODUCTION. Loss of joint function is only exploited in osteoarthritis (OA) once severe impairment is apparent. Animal models allow for lesion induction and serial OA progression measures. We recently described an adjustable non-surgical loading model for generating focal cartilage lesions in only the lateral femur joint compartment, in which regimes can be adjusted so that these either do or do not progress spontaneously. Herein, we use ventral plane videographic treadmill gait analysis to determine whether gait changes can be used to discriminate between stable and spontaneously progressing lesions, induced by these two loading regimes. METHODS. Animals encountered normal conditions, except during loading (9N, 40 cycles, 0.1 Hz, 10 sec/ cycle) which was applied to right knees in two groups (n=8) of 8-week-old male CBA mice: i) loaded once; ii) loaded 3 times/week for 2 weeks. Gait (including: brake, propel, stance, stride, stride length, stride frequency, steps and paw area) was assessed 3 times/week for 2 weeks in each mouse using a DigigaitTM treadmill. Thereafter, mice received 5mg/kg carprofen for analgesia and gait analysis repeated on 3 further alternate days. RESULTS. The two loading regimes produced virtually identical gait modifications with delayed onset (apparent on day 3) which remained unchanged for 2 weeks; mice loaded once only showed modified contralateral limb use, but those loaded multiply exhibited additional ipsilateral front limb modifications; no changes in gait were observed in loaded limbs. Intriguingly, the two regimes produced distinct responses to analgesia. Load-induced gait changes were completely rescued by carprofen in mice loaded only once, whilst those in mice loaded repetitively persisted. CONCLUSION. Our findings reveal specific and reproducible, compensatory changes in contralateral, non-loaded limb gait induced by any joint loading which produces focal articular lesions, and modified ipsilateral front limb use only when progressing lesions are induced by repetitive loading. We find that pain relief completely alleviates all gait modifications associated with stable lesions induced by single loading, but not those induced by repetitive loading. Differing responses in mice with stable and progressive articular cartilage load-induced lesions suggests that gait behaviour in a mechanical loading model of OA may predict joint degeneration

Purpose: Lower extremity articular fracture treatment requires acccurate diagnosis and anatomic reduction and fixation. As articular injuries, posterior malleolus (PM) fractures are still poorly defined: for example the incidence of associated PM marginal impaction and of free articular fragments is unknown. The purposes of this study were:. to define the articular injuries of PM fractures into clincially relevant groups, as complex articular injuries could require specific surgical steps;. to identify clinical and radiographic parameters which would alert the surgeon to the presence of complex injuries. Method: Our prospectively-collected orthopaedic trauma database (OTDB) query identified 796 ankle fractures treated operatively between 2003–2007. Of these 147 cases involved the posterior malleolus. Four were misclassified leaving 143 cases. We obtained demographic and injury data from the OTDB, and validated the OTDB coded mechanisms of injury by an individual chart review. We reviewed all radiographs to describe the PM injuries (fracture patterns and dimensions) and to identify the associated injuries. Results: Of the 143 cases: Mean age was 50 years (sd=19), 68.5% were female, 51% were right sided injuries, and the median ISS=4 (in fact, 97.5% had ISS=4, most therefore being isolated trauma). The mean post malleolus AP size=11mm (sd=5). We identified recurrent patterns and classified the PM fracture as SIMPLE or COMPLEX (to include marginal impaction or free comminuted fragment, which should be anatomically reduced), 42% of cases (60/143) were COMPLEX (18 were impaction, 42 were free fragment). To help clinicians identify which cases could be COMPLEX we correlated (Chi-sq) the presence of a COMPLEX PM fracture to common clinical and radiographic variables. COMPLEX PM were statistically significantly associated with (p values). an axial loading injury mechanism (.000),. a radiographically captured dislocation (.006),. posteromedial comminution [as defined Tor-netta] (.005). the size of the fragment (.000). For example, axial loading would result in a complex fracture in > 85% of cases. In contrast, there was a statistically significant association between a Weber C fracture and older age and the presence of a SIMPLE PM fracture. These factors being potentially “protective” from joint comminution. Conclusion: We have defined and quantified the PM articular lesions which require anatomic reduction and fixation, beyond what has been published. We have defined clinical and radiographic criteria which, because higly associated with COMPLEX lesions, could. prompt surgeons to order further imaging (CT) to better delineate the lesion, and. draw his/her attention to potentially malaligned fragments at the time surgery

Purpose: To describe functional results following revision ACL reconstruction surgery. Methods: Patients more than 2 years post-operative from revision ACL surgery by the same surgeon were asked to participate. Patient-based evaluation was determined by ACL Quality of Life(QOL) and Lysholm scores while clinical evaluation was based on IKDC and KT1000 Arthrometer scoring. Surgical information and radiographs were reviewed to identify associated pathologies and surgical technique. Results: Of 18 eligible patients, 15 were available for review(10 male, 5 female). Average age was 29 years(24–52); average follow-up time was 45.6 months(24–120). Primary ACL reconstructions failed due to surgical technique in 3 patients(20%), while trauma led to failure in 11 patients (73%). One patient failed due to previously unrecognized posterolateral instability and required an osteotomy at revision surgery. During revision surgery, 12 patients received a hamstring graft (10 contralateral, 2 ipsilateral) and 3 patients received a tibial posterior allograft. The most frequent concomitant procedures were a partial medial meniscectomy(3) and chondroplasty (5). Based on latest follow-ups, 7 patients had +2 grade on Lachman’s test, 4 patients had +1 grade and 4 patients had a negative grade. IKDC evaluation classified 3 patients as ‘normal’, 4 as ‘nearly normal’, 3 as ‘abnormal’ and 1 as ‘severely abnormal’. Autograft patients had a mean side-to-side difference of 2.8mm while allograft patients had a mean difference of 4.5 mm. Patient-rated Lysholm scores indicated that 4 patients received a ‘good’ score (84–94), 5 patients a ‘fair’ score (65–83) and 3 patients a ‘poor’ score (0–64). The average QOL score was 58.2%(12–96%). Patients characterized as having poor clinical and patient-rated results also had significant articular lesions identified during surgery. Conclusions: Results of revision surgery do not appear to be as good as previously published reports of primary reconstructions. Consideration must be given to the status of the articular cartilage, as it appears to be an important factor in determining the overall functional result

We report our experience of four initial cases of mosaicplasty using large plugs in four cases and subsequently fourteen cases using the OATS technique and large grafts. The average size of the articular lesion was 1.7 sq cm with a range of 1–3 sq cm. The average number of grafts used was 2.3 with a range of 1.5. The average size was 9 mm with a range of 4–10 mm. Including a poor result due to infection, pain was only found in three patients on activity (17%). The Tegner score and the IKDC score improved significantly. The initial four cases of mosaicplasty resulted in two cases having donor site pain and crepitus which required a lateral release. Using the OATS technique reconstructing the donor site no further cases of pain and crepitus occurred. On MRI imaging, the recipient site was congruous, intact and appeared functional and only one patient demonstrated protuberance of the articular cartilage (1mm). Recipient site marrow oedema, fluid accumulation or kissing tibial signals were not significant features. The donor site articular cartilage was congruent in 5 patients and homogeneously isointense in 6 out of 7 patients. We have modified the technique and used osteochondral transplantation to treat isolated articular cartilage defects of 1–3 sq cm in area, using a mini open technique and multiple large grafts, avoiding graft impaction and with reconstruction of the donor site. This technique has resulted in an 89% success rate at an average of 2.5 years post operatively. Eighty three per cent of patients were able to return to recreational sports. MRI follow up has shown no cause for concern and demonstrates incorporation of all the grafts. The success reported in this study is higher than reported elsewhere but this may reflect the use of the modified technique

The cancellous bone adjacent to major load-bearing joints such as the hip and knee has complex architecture. The loading patterns across these joints influence the architecture of the cancellous bone, which varies according to the magnitude and direction of these forces. Articular lesions are associated with alterations in the loading patterns and hence change to the cancellous architecture. The fractal dimension, as a numerical descriptor of complex shapes, enables these changes to be quantitated. The fractal analysis was performed by a box counting method. The perimeter of binary profiles of cancellous bone samples was measured for different box sizes. The fractal dimension is 1-D (where D is the slope of the straight-line segments from the plot of log of perimeter versus of log box size). Samples of cancellous bone were taken at autopsy from three subchondral regions, superior to the fovea in the femoral head (n=56) and the tibial (n=25) and femoral (n=25) condyles of the knee. There were three straight-line segments identified on the log-log plot, for each subject, indicating a fractal dimension over three different ranges of scale. Fractal 1 describes the complexity of bone surface detail influenced by osteoclast and osteoblast activity, fractal 2 describes the shape or form of individual trabeculae and fractal 3 describes the overall spatial complexity of the cancellous structure. The results show that for fractal 1, all three regions are the same. For fractal 2, the femoral head is greater than the condyles (1.40±0.07 versus 1.36±0.05 and 1.36±0.05) and for fractal 3, the femoral head is significantly greater than the condyles (1.76±0.06 versus 1.73±0.04 and 1.70±0.05). These data show that cancellous bone architecture differs between skeletal sites. In particular, the fine surface detail influenced by bone cell activity and described by fractal 1 is the same in each region, while the shape of individual trabeculae as described by fractal 2 is more complex in the femoral head. The overall spatial complexity of the cancellous structure as described by fractal 3 is the same in each condyle of the knee while in the femoral head it is significantly greater. The fractal dimension, as a descriptor of complexity, enables the effect of differences in the mechanical micro-environment on cancellous bone architecture to be quantified so that pathology affecting these regions can be studied

Purpose: There is still debate on classification, pathogenesis, and treatment of partial non-full thickness tears of the rotator cuff. We assessed mid-term outcome after arthroscopic repair. Material and methods: Between 1990 and 1998, 208 partial tears of the rotator cuffs were treated in our unit. Eighty patients were reviewed by an examiner different and independent from the surgery team. The review included a physical examination, Constant score and radiography. The series included 42 men and 38 women, mean age 52 years (23–73) who were seen at a mean follow-up of 59 months (17–118). We identified four groups: group 1 included lesions of the deep articular aspect of the supraspinatus: 34 cases; group 2 included tears of the superficial aspect: 27 cases; group 3 included tears involving both the deep and superficial aspect without full-thickness tear on the preoperative arthrogram; and group 4 included lesions involving a partial tear of the supraspinatus associated with another articular lesion. Acromioplasty was performed in all cases associated with section of the acromiocoracoid ligament. Results: Absolute Constant score progressed from 53 points preoperatively to 80 points at last follow-up. Mean Constant score of the contralateral shoulder was 87 points. There was a significant difference between outcome in the first three groups where the mean age was 50 years and the fourth group (trauma context) where the mean age was 36 years. Constant score was 84.7, 92, 92, and 73 for groups 1, 2, 3 and 4 respectively. There was no statistically significant improvement compared with the preoperative Constant score (67 points). Radiographically, there was no change in the subacromial space. Superficial lesions were more frequently associated with type 3 acromial impingement. Discussion: Globally, we observed a deterioration of outcome with time compared with the first review, with 76% satisfactory results at five years. The same outcome was obtained with superficial and deep lesions. We are in agreement with others that it is necessary to identify a subgroup of patients under 40 years of age with a partial tear of the rotator cuff in a trauma context. For these patients, arthroscopic acromioplasty is not a satisfactory therapeutic approach. The causal lesion (posterosuperior impingement, rim injury or instability) should be treated

It is recognised that as the severity of hallux valgus (HV) worsens, so do the clinical and radiological signs of arthritis in the first metatarsophalangeal joint. However, few studies specifically document the degenerate changes. The purpose of this study is to determine if intraoperative mapping of articular erosive lesions of the first MTP joint can be correlated to clinical and/or radiographic parameters used during the preoperative assessment of the HV deformity. Materials & Methods. We prospectively analysed 50 patients who underwent surgery between Jan 2009 & Jan 2010. Patients with a known history of previous first metatarsophalangeal joint surgical intervention, trauma, or systemic arthritis were excluded from analysis. Preoperative demographics and AOFAS scores were recorded. Radiographic measurements were obtained from weight bearing radiographs. Intraoperative evaluation of the first metatarsal head, base of the proximal phalanx, and sesamoid articular cartilage erosion was performed. Cartilage wear was documented using International Cartilage Research Society grading. Results. three patients did not have scoring or cartilage wear documentation carried out and were excluded. The mean age was 56 years. The mean hallux valgus angle was 31 degrees. The mean IMA was 15 degrees. The mean AOFAS score was 62. Patients with no inferomedial (IM) and inferolateral (IL) wear had significantly better AOFAS score than patients who had IM & IL wear (p < 0.05). Patients who had IM & IL wear had a significantly higher HVA (p < 0.05). There was a significant positive correlation between hallux valgus angle and AOFAS score. We also found correlation between sesamoid wear and AOFAS score and HV angle. Conclusion. we conclude that preoperative clinical and radiographic measurements can be used to predict the incidence and location of articular erosions in the 1st MTPJ and are helpful in the preoperative assessment of the HV deformity

A review of 100 consecutive patients who underwent knee arthroscopy within 1 month of Magnetic Resonance Imaging (MRI) of the knee took place to assess the role of Magnetic Resonance Imaging in regard to assessment of intra articular pathology. The study period was from 15th April 1998 to 19th September 2000. The study compared the MRI report with the operative findings of one surgeon documented with average of 20 photos per patient. The enclosed tables document the sensitivity and specificity in regard to articular cartilage of the patella, trochlearand medial femoral condyle. Medial meniscal and lateral meniscal pathology was reviewed as was anterior cruciate ligament. The study would suggest that whilst MRI is useful for assessment of meniscal pathology it is not highly accurate for assessment of articular surface lesions and anterior cruciate ligament pathology

Purpose: The confirmation of clinical findings as well as the accurate preoperative evaluation of patients with shoulder instability and rupture of the glenoid labrum. Material-Method: 180 patients with shoulder instability or suspected labral lesions were examined with MR arthrography. Results: The MR arthrography findings were the following: lesions of the labrum, SLAP lesions, redundant articular capsule, lesions of the capsule, lesions of the glenohumeral ligaments. In particular, we present: a) The spectrum of labral ruptures: Bankart lesions, SLAP, HAGL, ALPSA, GLAD lesions), b) various lesions of the labrum: degenerative changes, discoid labrum. In a few cases with MDI the MR arthrography was negative. Fifty (50) patients of these were operated upon. We report the results and compare the MR arthrography findings with those of the operation. SLAP type II lesions are difficult to be distinguished from normal conditions. Conclusions: MR arthrography is a reliable method in the study of shoulder instability and offers significantly in the treatment of this group of patients

Heterotopic ossification (HO) of the hip after injury to the central nervous system can lead to joint ankylosis. Surgery is usually delayed to avoid recurrence, even if the functional status is affected. We report a consecutive series of patients with HO of the hip after injury to the central nervous system who required surgery in a single, specialised tertiary referral unit. As was usual practice, they all underwent CT to determine the location of the HO and to evaluate the density of the femoral head and articular surface. The outcome of surgery was correlated with the pre-, peri- and post-operative findings.

In all, 183 hips (143 patients) were included of which 70 were ankylosed. A total of 25 peri-operative fractures of the femoral neck occurred, all of which arose in patients with ankylosed hips and were associated with intra-articular lesions in 18 and severe osteopenia of the femoral head in seven. All the intra-articular lesions were predicted by CT and strongly associated with post-operative complications.

The loss of the range of movement before ankylosis is a more important factor than the maturity of the HO in deciding the timing of surgery. Early surgical intervention minimises the development of intra-articular pathology, osteoporosis and the resultant complications without increasing the risk of recurrence of HO.

The repair of chondral lesions associated with femoroacetabular impingement requires specific treatment in addition to that of the impingement. In this single-centre retrospective analysis of a consecutive series of patients we compared treatment with microfracture (MFx) with a technique of enhanced microfracture autologous matrix-induced chondrogenesis (AMIC).

Acetabular grade III and IV chondral lesions measuring between 2 cm² and 8 cm² in 147 patients were treated by MFx in 77 and AMIC in 70. The outcome was assessed using the modified Harris hip score at six months and one, two, three, four and five years post-operatively. The outcome in both groups was significantly improved at six months and one year post-operatively. During the subsequent four years the outcome in the MFx group slowly deteriorated, whereas that in the AMIC group remained stable. Six patients in the MFx group subsequently required total hip arthroplasty, compared with none in the AMIC group

We conclude that the short-term clinical outcome improves in patients with acetabular chondral damage following both MFx and AMIC. However, the AMIC group had better and more durable improvement, particularly in patients with large (≥ 4 cm²) lesions.

Cite this article: Bone Joint J 2015; 97-B:628–35.

The cam-type deformity in femoroacetabular impingement is a 3D deformity. Single measurements using radiographs, CT or MRI may not provide a true estimate of the magnitude of the deformity. We performed an analysis of the size and location of measurements of the alpha angle (α°) using a CT technique which could be applied to the 3D reconstructions of the hip. Analysis was undertaken in 42 patients (57 hips; 24 men and 18 women; mean age 38 years (16 to 58)) who had symptoms of femoroacetabular impingement related to a cam-type abnormality. An α° of > 50° was considered a significant indicator of cam-type impingement. Measurements of the α° were made at different points around the femoral head/neck junction at intervals of 30°: starting at the nine o’clock (posterior), ten, eleven and twelve o’clock (superior), one, two and ending at three o’clock (anterior) position.

The mean maximum increased α° was 64.6° (50.8° to 86°). The two o’clock position was the most common point to find an increased α° (53 hips; 93%), followed by one o’clock (48 hips; 84%). The largest α° for each hip was found most frequently at the two o’clock position (46%), followed by the one o’clock position (39%). Generally, raised α angles extend over three segments of the clock face.

Single measurements of the α°, whether pre- or post-operative, should be viewed with caution as they may not be representative of the true size of the deformity and not define whether adequate correction has been achieved following surgery.

Cite this article: Bone Joint J 2014;96-B:1167–71.